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Sample records for charr salvelinus fontinalis

  1. Comparative transcriptomics of anadromous and resident brook charr Salvelinus fontinalis before their first salt water transition

    Directory of Open Access Journals (Sweden)

    Marylène BOULET, Éric NORMANDEAU, Bérénice BOUGAS, Céline AUDET,Louis BERNATCHEZ

    2012-02-01

    Full Text Available Most salmonid taxa have an anadromous life history strategy, whereby fish migrate to saltwater habitats for a growth period before returning to freshwater habitats for spawning. Moreover, several species are characterized by different life history tactics whereby resident and anadromous forms may occur in genetically differentiated populations within a same species, as well as polymorphism within a population. The molecular mechanisms underlying the physiological differences between anadromous and resident forms during the first transition from freshwater to saltwater environments are only partially understood. Insofar research has typically focused on species of the genus Salmo. Here, using a 16,000 cDNA array, we tested the hypothesis that anadromous brook charr Salvelinus fontinalis are characterized by differences in their transcriptome relative to resident brook charr before the anadromous fish migration. Families originating from parapatric populations of anadromous and resident charr were reared in controlled environments mimicking natural temperature and photoperiod, and sampled in spring, while still in fresh water. While anadromous and resident charr showed similar transcriptome profiles in white muscle, they were characterized by striking differences in their gill transcriptome profiles. Genes that were upregulated in the gills of anadromous charr were principally involved in metabolism (mitochondrial electron transport chain, glucose metabolism, and protein synthesis, development (tissue differentiation and innate immunity. We discuss the nature of these transcriptomic differences in relation to molecular mechanisms underlying the expression of anadromous and resident life history tactics and suggest that the anadromous charr express some of the molecular processes present in other migratory salmonids [Current Zoology 58 (1: 158–170, 2012].

  2. Behavioural thermoregulatory tactics in lacustrine brook charr, Salvelinus fontinalis.

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    Andrea Bertolo

    Full Text Available The need to vary body temperature to optimize physiological processes can lead to thermoregulatory behaviours, particularly in ectotherms. Despite some evidence of within-population phenotypic variation in thermal behaviour, the occurrence of alternative tactics of this behaviour is rarely explicitly considered when studying natural populations. The main objective of this study was to determine whether different thermal tactics exist among individuals of the same population. We studied the behavioural thermoregulation of 33 adult brook charr in a stratified lake using thermo-sensitive radio transmitters that measured hourly individual temperature over one month. The observed behavioural thermoregulatory patterns were consistent between years and suggest the existence of four tactics: two "warm" tactics with both crepuscular and finer periodicities, with or without a diel periodicity, and two "cool" tactics, with or without a diel periodicity. Telemetry data support the above findings by showing that the different tactics are associated with different patterns of diel horizontal movements. Taken together, our results show a clear spatio-temporal segregation of individuals displaying different tactics, suggesting a reduction of niche overlap. To our knowledge, this is the first study showing the presence of behavioural thermoregulatory tactics in a vertebrate.

  3. Comparative transcriptomics of anadromous and resident brook charr Salvelinus fontinalis before their first salt water transition

    Institute of Scientific and Technical Information of China (English)

    Marylène BOULET; (E)ric NORMANDEAU; Bérénice BOUGAS; Cé1ine AUDET; Louis BERNATCHEZ

    2012-01-01

    Most salmonid taxa have an anadromous life history strategy,whereby fish migrate to saltwater habitats for a growth period before returning to freshwater habitats for spawning.Moreover,several species are characterized by different life history tactics whereby resident and anadromous forms may occur in genetically differentiated populations within a same species,as well as polymorphism within a population.The molecular mechanisms underlying the physiological differences between anadromous and resident forms during the first transition from freshwater to saltwater environments are only partially understood.Insofar research has typically focused on species of the genus Salmo.Here,using a 16,000 cDNA array,we tested the hypothesis that anadromous brook charr Salvelinus fontinalis are characterized by differences in their transcriptome relative to resident brook charr before the anadromous fish migration.Families originating from parapatric populations of anadromous and resident charr were reared in controlled environments mimicking natural temperature and photoperiod,and sampled in spring,while still in fresh water.While anadromous and resident charr showed similar transcriptome profdes in white muscle,they were characterized by striking differences in their gill transcriptome profiles.Genes that were upregulated in the gills of anadromous charr were principally involved in metabolism (mitochondrial electron transport chain,glucose metabolism,and protein synthesis),development (tissue differentiation) and innate immunity.We discuss the nature of these transcriptomic differences in relation to molecular mechanisms underlying the expression of anadromous and resident life history tactics and suggest that the anadromous chart express some of the molecular processes present in other migratory salmonids [Current Zoology 58 (1):158-170,2012].

  4. Heritability of life-history tactics and genetic correlation with body size in a natural population of brook charr (Salvelinus fontinalis).

    Science.gov (United States)

    Thériault, V; Garant, D; Bernatchez, L; Dodson, J J

    2007-11-01

    A common dimorphism in life-history tactic in salmonids is the presence of an anadromous pathway involving a migration to sea followed by a freshwater reproduction, along with an entirely freshwater resident tactic. Although common, the genetic and environmental influence on the adoption of a particular life-history tactic has rarely been studied under natural conditions. Here, we used sibship-reconstruction based on microsatellite data and an 'animal model' approach to estimate the additive genetic basis of the life-history tactic adopted (anadromy vs. residency) in a natural population of brook charr, Salvelinus fontinalis. We also assess its genetic correlation with phenotypic correlated traits, body size and body shape. Significant heritability was observed for life-history tactic (varying from 0.52 to 0.56 depending on the pedigree scenario adopted) as well as for body size (from 0.44 to 0.50). There was also a significant genetic correlation between these two traits, whereby anadromous fish were genetically associated with bigger size at age 1 (r(G) = -0.52 and -0.61). Our findings thus indicate that life-history tactics in this population have the potential to evolve in response to selection acting on the tactic itself or indirectly via selection on body size. This study is one of the very few to have successfully used sibship-reconstruction to estimate quantitative genetic parameters under wild conditions. PMID:17956389

  5. The influence of gene-environment interactions on GHR and IGF-1 expression and their association with growth in brook charr, Salvelinus fontinalis (Mitchill

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    Blier Pierre

    2007-12-01

    Full Text Available Abstract Background Quantitative reaction norm theory proposes that genotype-by-environment interaction (GxE results from inter-individual differences of expression in adaptive suites of genes in distinct environments. However, environmental norms for actual gene suites are poorly documented. In this study, we investigated the effects of GxE interactions on levels of gene transcription and growth by documenting the impact of rearing environment (freshwater vs. saltwater, sex and genotypic (low vs. high estimated breeding value EBV effects on the transcription level of insulin-like growth factor (IGF-1 and growth hormone receptor (GHR in brook charr (Salvelinus fontinalis. Results Males grew faster than females (μ♀ = 1.20 ± 0.07 g·d-1, μ♂ = 1.46 ± 0.06 g·d-1 and high-EBV fish faster than low-EBV fish (μLOW = 0.97 ± 0.05 g·d-1, μHIGH = 1.58 ± 0.07 g·d-1; p FW = 1.52 ± 0.07 g·d-1, μSW = 1.15 ± 0.06 g·d-1, yet GHR mRNA transcription level was significantly higher in saltwater than in freshwater (μSW = 0.85 ± 0.05, μFW = 0.61 ± 0.05. The ratio of actual growth to units in assayed mRNA ('individual transcript efficiency', iTE; g·d-1·u-1 also differed among EBV groups (μLOW = 2.0 ± 0.24 g·d-1·u-1; μHIGH = 3.7 ± 0.24 g·d-1·u-1 and environments (μSW = 2.0 ± 0.25 g·d-1·u-1; μFW = 3.7 ± 0.25 g·d-1·u-1 for GHR. Males had a lower iTE for GHR than females (μ♂ = 2.4 ± 0.29 g·d-1·u-1; μ♀ = 3.1 ± 0.23 g·d-1·u-1. There was no difference in IGF-1 transcription level between environments (p > 0.7 or EBV groups (p > 0.15 but the level of IGF-1 was four times higher in males than females (μ♂ = 2.4 ± 0.11, μ♀ = 0.58 ± 0.09; p ♂ = 1.3 ± 0.59 g·d-1·u-1; μ♀ = 3.9 ± 0.47 g·d-1·u-1, salinities (μSW = 2.3 ± 0.52 g·d-1·u-1; μFW = 3.7 ± 0.53 g·d-1·u-1 and EBV-groups (μLOW = 2.4 ± 0.49 g·d-1·u-1; μHIGH = 3.8 ± 0.49 g·d-1·u-1. Interaction between EBV-group and environment was detected for

  6. Ecological diversity in the polymorphic fish Arctic charr (Salvelinus alpinus)

    OpenAIRE

    Woods, Pamela J., 1979-

    2011-01-01

    The Arctic charr Salvelinus alpinus is extremely diverse and its differentiation may indicate ecological speciation. This dissertation aims to compare trends in ecological diversity across broad geographical regions and place it within an ecosystem context by comparing study systems in Iceland and Alaska. In the first chapter, gut contents of Arctic charr across ~50 lakes in Iceland were analyzed to form 6 habitat-associated prey categories. Consumption of zooplankton was related to high sili...

  7. Radiocaesium turnover in Arctic charr (Salvelinus alpinus) and brown trout (Salmo trutta) in a Norwegian lake

    International Nuclear Information System (INIS)

    The radioactivity of brown trout (Salmo trutta L.) and Arctic charr (Salvelinus alpinus (L.)) was monitored in a Norwegian lake from 1986 to 1989. A distinct difference was observed between brown trout and Arctic charr in the accumulation of radiocaesium (134Cs and 137Cs) from the Chernobyl fallout, and the study focused on the understanding of this difference. Brown trout had a large food consumption and a corresponding high intake of radiocaesium. Excretion was 20% faster in brown trout than Arctic charr as brown trout lived at high temperatures in epilimnic water. Arctic charr had a lower food consumption (less than one-third of trout) and lived in colder meta-and hypolimnic water. Arctic charr therefore had a lower intake and slower excretion of radiocaesium. Brown trout an Arctic charr had different diets. For brown trout zoobenthos was the dominant food item, whereas Artic charr mainly fed on zooplankton. The radioactivity in the stomach contents of the two species was different in 1986, but similar for the rest of the period. Higher levels of radiocaesium in brown trout than Arctic charr in 1986 were due to a higher food consumption and more radioactive food items in its diet. The parallel development in accumulated radiocaesium through summer 1987 was probably formed by brown trout balancing a higher intake with a faster excretion. The ecological half-lives of radiocaesium in brown trout (357 days) and Arctic charr (550 days) from Lake Hoeysjoeen indicated a slow removal of the isotopes from the food webs. (author)

  8. Landlocked Arctic charr ( Salvelinus alpinus ) population structure and lake morphometry in Greenland - is there a connection?

    DEFF Research Database (Denmark)

    Riget, F.; Jeppesen, E.; Landkildehus, F.;

    2000-01-01

    in lakes with maximum depths >3 m. A dwarf form occurred in all lakes inhabited by Arctic charr and was the only form in lakes with maximum depths 20 m, large-sized charr were more abundant, and the length- frequency distribution of the population was bimodal, with a first mode around 10-12 cm and a second...... correlated with lake volume. Our study indicates that the charr population structure became more complex with increasing lake size. Moreover, the population structure seemed to be influenced by lake-water transparency and the presence or absence of three-spined stickleback (Gasterosteus aculeatus)......Landlocked Arctic charr (Salvelinus alphinus) populations in sub-Arctic and Arctic Greenland lakes were sampled with multi- mesh-sized survey gillnets. The study covered a range of small shallow lakes (0.01 km(2) maximum depth 200 In). Arctic charr were found in one to three different forms...

  9. Endocrine disruption in brook trout (Salvelinus fontinalis) exposed to leachate from a public refuse dump

    NARCIS (Netherlands)

    Noaksson, E.; Linderoth, M.; Bosveld, A.T.C.; Norrgren, L.; Zebühr, Y.; Balk, L.

    2003-01-01

    Lake Molnbyggen was previously found to harbour a large number of sexually immature female perch (Perca fluviatilis) suffering from endocrine disruption. In an attempt to pin-point the source of the endocrine-disrupting substance(s) (EDSs), brook trout (Salvelinus fontinalis) from Vadbacken, a strea

  10. Morphological divergence in a trimorphic population of Arctic charr (Salvelinus alpinus (L.)) in Skogsfjordvatn, northern Norway.

    OpenAIRE

    Skoglund, Sigrid Østrem

    2013-01-01

    Sympatric polymorphisms are found in many freshwater fish taxa, including the salmonid Arctic charr (Salvelinus alpinus (L.)). Polymorphism is often expressed as differences in morphology, behaviour and life-history strategies, and may be driven by alternative phenotypic adaptations to resource use such as habitat and prey preferences. Morphological divergence is usually linked to different functions of the morphological trait. Here, I study the correlations between morphology and ecological ...

  11. The pineal gland of Arctic charr (Salvelinus alpinus L.): a survey of seasonal melatonin production and gland ultrastructure

    OpenAIRE

    Musæus, Fredrikke Johansen

    2009-01-01

    The pineal gland is part of the endocrine system involved with rhythmic activity in e.g. fish. The main product of the pineal gland is the indole hormone melatonin, synthesised from the amino acid tryptophan. Melatonin is mainly synthesized when it is dark, as light inhibit the production. For this reason melatonin is thought to be strongly involved in biological rhythms. Arctic charr (Salvelinus alpinus) is a circumpolar species and anadromous in parts of its distribution area. Arctic charr ...

  12. Cytogenetic and histological studies of the brook trout (Salvelinus fontinalis) x arctic charr (Salvelinus alpinus) hybrids

    OpenAIRE

    Lisboa, Rodrigo

    2012-01-01

    In aquaculture, application of fish hybrids has increased. This technique permits improvement of the fish production by providing specimens showing better growth rate when compared to the parental species. Indeed, sterile individuals are highly demanded because quite frequently parental fish mature before they reach the market size, which impairs their growth and decrease their economic value. Throughout the last years, the commercial and scientific interest in salmonids has increased rapidly...

  13. Land-locked Arctic charr (Salvelinus alpinus) population structure and lake morphometry in Greenland - is there a connection?

    DEFF Research Database (Denmark)

    Riget, F.; Jeppesen, E.; Landkildehus, F.;

    2000-01-01

    in low numbers, the length-frequency distribution being unimodal with a tail towards large sizes. In lakes with a maximum depth >20 m, large-sized charr were more abundant, and the length-frequency distribution of the population was bi- modal, with a ®rst mode around 10±12 cm and a second mode around 26...... with lake volume. Our study indicates that the charr population structure became more complex with increasing lake size. More- over, the population structure seemed to be in¯uenced by lake-water transparency and the presence or absence of three-spined stickleback (Gasterosteus aculeatus).......Landlocked Arctic charr (Salvelinus alpinus) populations in sub-Arctic and Arctic Greenland lakes were sampled with multi-mesh-sized survey gillnets. The study covered a range of small shallow lakes (0.01 km2, maximum depth 200 m). Arctic charr...

  14. Area use of Arctic charr (Salvelinus alpinus) and brown trout (Salmo trutta) in an Arctic fjord system - a two year acoustic telemetry study

    OpenAIRE

    Kirkemoen, Odin Lagerborg

    2016-01-01

    The Arctic charr Salvelinus alpinus (L.) and the brown trout Salmo trutta L. are fish species with complex and comparable life strategies. However, there are also differences between the two species. The migratory behavior of Arctic charr and brown trout at sea is poorly understood compared to their far more studied behavior in fresh water. Because of the declining populations of anadromous Arctic charr the last decades, this species is particularly important to understand in order to mitigat...

  15. Growth and fatty acid composition of two strains of Arctic charr (Salvelinus alpinus) on diets formulated with low fish oil inclusion in a recirculating aquaculture system

    Science.gov (United States)

    Arctic charr (Salvelinus alpinus) is a highly desirable species to culture due to their fast growth, culture conditions and reputation as a sustainably produced fish due to closed containment culture. A study was conducted to evaluate two Arctic charr stocks (one commercial stock and one from the ...

  16. Concomitant Antibiotic and Mercury Resistance Among Gastrointestinal Microflora of Feral Brook Trout, Salvelinus fontinalis

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    Meredith, Matthew M.; Parry, Erin M.; Guay, Justin A.; Markham, Nicholas O.; Danner, G. Russell; Johnson, Keith A.; Barkay, Tamar; Fekete, Frank A.

    2013-01-01

    Twenty-nine bacterial isolates representing eight genera from the gastrointestinal tracts of feral brook trout Salvelinus fontinalis (Mitchell) demonstrated multiple maximal antibiotic resistances and concomitant broad-spectrum mercury (Hg) resistance. Equivalent viable plate counts on tryptic soy agar supplemented with either 0 or 25 μM HgCl2 verified the ubiquity of mercury resistance in this microbial environment. Mercury levels in lake water samples measured 1.5 ng L−1; mercury concentrations in fish filets ranged from 81.8 to 1,080 ng g−1 and correlated with fish length. The presence of similar antibiotic and Hg resistance patterns in multiple genera of gastrointestinal microflora supports a growing body of research that multiple selective genes can be transferred horizontally in the presence of an unrelated individual selective pressure. We present data that bioaccumulation of non-point source Hg pollution could be a selective pressure to accumulate both antibiotic and Hg resistant bacteria. PMID:22850694

  17. Life history strategies of a trimorphic population of Arctic charr (Salvelinus alpinus (L.)) in Skogsfjordvatn, northern-Norway

    OpenAIRE

    Smalås, Aslak

    2013-01-01

    Polymorphisms are widespread throughout many different taxa of vertebrates. Discrete polymorphisms or morphs usually differentiate in morphology, ecology and life history, most likely driven by adaptations to different habitats and resources. For sympatric morphs to be able to maximize fitness in different niches and habitats, they may develop differences in several life history traits. Arctic charr (Salvelinus alpinus (L.)) is a good model species for verifying and understanding ecological d...

  18. Life history differences between fat and lean morphs of lake charr (Salvelinus namaycush) in Great Slave Lake, Northwest Territories, Canada

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    Hansen, Michael J.; Nate, Nancy A.; Chavarie, Louise; Muir, Andrew M.; Zimmerman, Mara S.; Krueger, Charles C.

    2016-01-01

    Life history characteristics (size, age, plumpness, buoyancy, survival, growth, and maturity) were compared between fat and lean morphs of lake charr Salvelinus namaycush in Great Slave Lake, Canada, to determine if differences may reflect effects of resource polymorphism. Lake charr were sampled using graded-mesh gill nets set in three depth strata. Of 236 lake charr captured, 122 were a fat morph and 114 were a lean morph. Males and females did not differ from each other in any attributes for either fat or lean morphs. The fat morph averaged 15 mm longer, 481 g heavier, and 4.7 years older than the lean morph. The fat morph averaged 26% heavier and 48% more buoyant at length than the lean morph. Survival of the fat morph was 1.7% higher than that of the lean morph. The fat morph grew at a slower annual rate to a shorter asymptotic length than the lean morph. Fat and lean morphs matured at similar lengths and ages. We concluded that the connection between resource polymorphism and life histories in lean versus fat lake charr suggests that morph-specific restoration objectives may be needed in lakes where lake charr diversity is considered to be a restoration goal.

  19. Genetic Variability and Structuring of Arctic Charr (Salvelinus alpinus Populations in Northern Fennoscandia.

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    Takahito Shikano

    Full Text Available Variation in presumably neutral genetic markers can inform us about evolvability, historical effective population sizes and phylogeographic history of contemporary populations. We studied genetic variability in 15 microsatellite loci in six native landlocked Arctic charr (Salvelinus alpinus populations in northern Fennoscandia, where this species is considered near threatened. We discovered that all populations were genetically highly (mean FST ≈ 0.26 differentiated and isolated from each other. Evidence was found for historical, but not for recent population size bottlenecks. Estimates of contemporary effective population size (Ne ranged from seven to 228 and were significantly correlated with those of historical Ne but not with lake size. A census size (NC was estimated to be approximately 300 individuals in a pond (0.14 ha, which exhibited the smallest Ne (i.e. Ne/NC = 0.02. Genetic variability in this pond and a connected lake is severely reduced, and both genetic and empirical estimates of migration rates indicate a lack of gene flow between them. Hence, albeit currently thriving, some northern Fennoscandian populations appear to be vulnerable to further loss of genetic variability and are likely to have limited capacity to adapt if selection pressures change.

  20. Understanding environmental DNA detection probabilities: A case study using a stream-dwelling char Salvelinus fontinalis

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    Wilcox, Taylor M; Mckelvey, Kevin S.; Young, Michael K.; Sepulveda, Adam; Shepard, Bradley B.; Jane, Stephen F; Whiteley, Andrew R.; Lowe, Winsor H.; Schwartz, Michael K.

    2016-01-01

    Environmental DNA sampling (eDNA) has emerged as a powerful tool for detecting aquatic animals. Previous research suggests that eDNA methods are substantially more sensitive than traditional sampling. However, the factors influencing eDNA detection and the resulting sampling costs are still not well understood. Here we use multiple experiments to derive independent estimates of eDNA production rates and downstream persistence from brook trout (Salvelinus fontinalis) in streams. We use these estimates to parameterize models comparing the false negative detection rates of eDNA sampling and traditional backpack electrofishing. We find that using the protocols in this study eDNA had reasonable detection probabilities at extremely low animal densities (e.g., probability of detection 0.18 at densities of one fish per stream kilometer) and very high detection probabilities at population-level densities (e.g., probability of detection > 0.99 at densities of ≥ 3 fish per 100 m). This is substantially more sensitive than traditional electrofishing for determining the presence of brook trout and may translate into important cost savings when animals are rare. Our findings are consistent with a growing body of literature showing that eDNA sampling is a powerful tool for the detection of aquatic species, particularly those that are rare and difficult to sample using traditional methods.

  1. Hiding in Plain Sight: A Case for Cryptic Metapopulations in Brook Trout (Salvelinus fontinalis.

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    David C Kazyak

    Full Text Available A fundamental issue in the management and conservation of biodiversity is how to define a population. Spatially contiguous fish occupying a stream network have often been considered to represent a single, homogenous population. However, they may also represent multiple discrete populations, a single population with genetic isolation-by-distance, or a metapopulation. We used microsatellite DNA and a large-scale mark-recapture study to assess population structure in a spatially contiguous sample of Brook Trout (Salvelinus fontinalis, a species of conservation concern. We found evidence for limited genetic exchange across small spatial scales and in the absence of barriers to physical movement. Mark-recapture and stationary passive integrated transponder antenna records demonstrated that fish from two tributaries very seldom moved into the opposite tributary, but movements between the tributaries and mainstem were more common. Using Bayesian genetic clustering, we identified two genetic groups that exhibited significantly different growth rates over three years of study, yet survival rates were very similar. Our study highlights the importance of considering the possibility of multiple genetically distinct populations occurring within spatially contiguous habitats, and suggests the existence of a cryptic metapopulation: a spatially continuous distribution of organisms exhibiting metapopulation-like behaviors.

  2. Impacts of a gape limited Brook Trout, Salvelinus fontinalis, on larval Northwestern salamander, Ambystoma gracile, growth: A field enclosure experiment

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    Currens, C.R.; Liss, W.J.; Hoffman, R.L.

    2007-01-01

    The formation of amphibian population structure is directly affected by predation. Although aquatic predators have been shown to have direct negative effects on larval salamanders in laboratory and field experiments, the potential impacts of gape-limited fish on larval salamander growth has been largely underexplored. We designed an enclosure experiment conducted in situ to quantify the effects of gape-limited Brook Trout (Salvelinus fontinalis) on larval Northwestern Salamander (Ambystoma gracile) growth. We specifically tested whether the presence of fish too small to consume larvae had a negative effect on larval growth. The results of this study indicate that the presence of a gape-limited S. fontinalis can have a negative effect on growth of larval A. gracile salamanders. Copyright 2007 Society for the Study of Amphibians and Reptiles.

  3. Histology and DNA cytophotometry of the pancreas of acid exposed brook trout (Salvelinus fontinalis)

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    Mudge, J.E.

    1970-01-01

    The gross anatomy and histology of the pancreas were studied in untreated and acid exposed brook trout (Salvelinus fontinalis). Also, three fixatives (4% formalin, Zenker-formol, and Bouin's) and four staining procedures (hematoxylin and eosin, phloxine-methylene blue, Mallory-Heidenhain's azan, and chromium-hematoxylin-phloxine) were evaluated in terms of their utility for histological studies of the brook trout pancreas. Finally, the exocrine cells of control and acid exposed trout were examined cytophotometrically to determine feulgen DNA content. Briefly, the major findings were as follows: although pancreatic tissue in the brook trout is diffusely scattered among the pyloric caeca and mesenteries bordering hepatic, splenic and small intestinal areas, and bulk of the gland resides next to the pyloric stomach and its entrance into the small intestine; pancreatic islets are also most numerous and best developed in this region; endocrine islets are composed of two granular cell types: Basophilic beta cells which comprise more than 70% of the islet and alpha cells which are scattered singly throughout each islet; histochemical analysis of F-DNA content of exocrine pancreas under control and experimental conditions indicates that these cells were not influenced by acute acid exposure; no histopathological changes were found in either endocrine or exocrine cells which could be attributed to prior exposure of trout to acid pH; and Mallory-Heidenhain's azan staining of Zenker-formol fixed tissue specimens proved to be an excellent stain for histological studies of both endocrine and exocrine components of the trout pancreas.

  4. Spatial and temporal movement dynamics of brook Salvelinus fontinalis and brown trout Salmo trutta

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    Davis, L.A.; Wagner, Tyler; Barton, Meredith L.

    2015-01-01

    Native eastern brook trout Salvelinus fontinalis and naturalized brown trout Salmo trutta occur sympatrically in many streams across the brook trout’s native range in the eastern United States. Understanding within- among-species variability in movement, including correlates of movement, has implications for management and conservation. We radio tracked 55 brook trout and 45 brown trout in five streams in a north-central Pennsylvania, USA watershed to quantify the movement of brook trout and brown trout during the fall and early winter to (1) evaluate the late-summer, early winter movement patterns of brook trout and brown trout, (2) determine correlates of movement and if movement patterns varied between brook trout and brown trout, and (3) evaluate genetic diversity of brook trout within and among study streams, and relate findings to telemetry-based observations of movement. Average total movement was greater for brown trout (mean ± SD = 2,924 ± 4,187 m) than for brook trout (mean ± SD = 1,769 ± 2,194 m). Although there was a large amount of among-fish variability in the movement of both species, the majority of movement coincided with the onset of the spawning season, and a threshold effect was detected between stream flow and movement: where movement increased abruptly for both species during positive flow events. Microsatellite analysis of brook trout revealed consistent findings to those found using radio-tracking, indicating a moderate to high degree of gene flow among brook trout populations. Seasonal movement patterns and the potential for relatively large movements of brook and brown trout highlight the importance of considering stream connectivity when restoring and protecting fish populations and their habitats.

  5. Quantitative evaluation of macrophage aggregates in brook trout Salvelinus fontinalis and rainbow trout Oncorhynchus mykiss

    Science.gov (United States)

    Schwindt, Adam R.; Truelove, Nathan; Schreck, Carl B.; Fournie, John W.; Landers, Dixon H.; Kent, Michael L.

    2006-01-01

    Macrophage aggregates (MAs) occur in various organs of fishes, especially the kidney, liver and spleen, and contain melanin, ceroid/lipofuscin and hemosiderin pigments. They have been used as indicators of a number of natural and anthropogenic stressors. Macrophage aggregates occur in salmonids but are poorly organized, irregularly shaped, and are generally smaller than those in derived teleosts. These features complicate quantification, and thus these fishes have seldom been used in studies correlating MAs with environmental stressors. To alleviate these complications, we developed color filtering algorithms for use with the software package ImagePro Plus® (Media Cybernetics) that select and quantify pigmented area (i.e. colors ranging from gold to brown to black) in tissue sections. Image analysis results compared well with subjective scoring when tested on brook trout Salvelinus fontinalis and rainbow trout Oncorhynchus mykiss captured from high-elevation lakes or hatcheries. Macrophage aggregate pigments correlated positively with age and negatively with condition factor. Within individual fish, pigmentation correlated positively among organs, suggesting that the kidney, liver or spleen are suitable indicator organs. In age-matched fishes, MA pigments were not different between hatcheries and lakes in the organs examined. Between lakes, differences in pigments were observed in the kidney and spleen, but were not explained by age, condition factor, sex or maturation state. Our results indicate that quantification of the area occupied by MA pigments is an efficient and accurate means of evaluating MAs in salmonid organs and that organ pigmentation correlates with age and condition factor, as seen in studies with more derived fishes. 

  6. Hybridization between native white-spotted charr and nonnative brook trout in the upper Sorachi River, Hokkaido, Japan

    OpenAIRE

    Kitano, Satoshi; Ohdachi, Satoshi; Koizumi, Itsuro; Hasegawa, Koh

    2013-01-01

    Invasion status and impacts of nonnative brook trout (Salvelinus fontinalis) in a Hokkaido stream were investigated with field surveys and genetic analyses. Nonnative brook trout was detected in nine (41 %) of the 22 sampled reaches in three tributaries of the Sorachi River, Hokkaido, Japan. Based on the external pigmentation, twelve putative hybrids between brook trout and native white-spotted charr (Salvelinus leucomaenis) were collected in two reaches. Microsatellite and mitochondrial DNA ...

  7. Seasonal Differences in Relative Gene Expression of Putative Central Appetite Regulators in Arctic Charr (Salvelinus alpinus Do Not Reflect Its Annual Feeding Cycle.

    Directory of Open Access Journals (Sweden)

    Anja Striberny

    Full Text Available The highly seasonal anadromous Arctic charr (Salvelinus alpinus was used to investigate the possible involvement of altered gene expression of brain neuropeptides in seasonal appetite regulation. Pro-opiomelanocortin (POMCA1, POMCA2, Cocaine and amphetamine regulated transcript (CART, Agouti related Peptide (AgRP, Neuropeptide Y (NPY and Melanocortin Receptor 4 (MC4-R genes were examined. The function of centrally expressed Leptin (Lep in fish remains unclear, so Lep (LepA1, LepA2 and Leptin Receptor (LepR genes were included in the investigation. In a ten months study gene expression was analysed in hypothalamus, mesencephalon and telencephalon of immature charr held under natural photoperiod (69°38'N and ambient temperature and given excess feed. From April to the beginning of June the charr did not feed and lost weight, during July and August they were feeding and had a marked increase in weight and condition factor, and from November until the end of the study the charr lost appetite and decreased in weight and condition factor. Brain compartments were sampled from non-feeding charr (May, feeding charr (July, and non-feeding charr (January. Reverse transcription real-time quantitative PCR revealed temporal patterns of gene expression that differed across brain compartments. The non-feeding charr (May, January had a lower expression of the anorexigenic LepA1, MC4-R and LepR in hypothalamus and a higher expression of the orexigenic NPY and AgRP in mesencephalon, than the feeding charr (July. In the telencephalon, LepR was more highly expressed in January and May than in July. These results do not indicate that changes in central gene expression of the neuropeptides investigated here directly induce seasonal changes in feeding in Arctic charr.

  8. Arctic charr (Salvelinus alpinus squeezed in a complex fish community dominated by perch (Perca fluviatilis

    Directory of Open Access Journals (Sweden)

    Odd Terje Sandlund

    2013-12-01

    Full Text Available In the complex fish community of Lake Skasen, southeastern Norway, the relative population density, habitat use and diet of Arctic charr, perch, roach and burbot was studied by a gill net survey during June-September 2010. A marked segregation in habitat use was observed, with Arctic charr and burbot captured in the profundal and deepest part of the pelagic habitat, and perch and roach captured in the littoral and upper part of the pelagic. Perch dominated the total catches, followed by roach. Arctic charr occurred in low numbers in the catches, and also had a low annual growth rate. Even in June, at low water temperatures, Arctic charr were confined to the profundal. Both Arctic charr, roach and perch fed on the same cladocerans, but all size groups of perch had fish as an important part of the diet. Analysis of stable carbon and nitrogen isotopes revealed a narrow trophic niche of Arctic charr, positioned at the extreme pelagic end of the carbon gradient relative to the other fish species. These had a wider span of δ13C signatures, but more positioned towards the littoral end of the carbon gradient. The low growth rate of Arctic charr, despite a low population density, indicates that food is a limiting resource for charr in this lake, probably due to a confinement to the profundal habitat as a result of competition and predator avoidance. Since all age-classes of Arctic charr seem to be enclosed in the profundalhabitat, intraspecific competition and predation may be supplementary stressors resulting in low annual recruitment and low population density, as well as low individual growth rate, i.e. the population is squeezed. The narrow trophic niche of Arctic charr compared to perch, roach and burbot, revealed by stable isostope analysis, supports this conclusion.

  9. Optimal swimming speeds reflect preferred swimming speeds of brook charr (Salvelinus fontinalis Mitchill, 1874)

    OpenAIRE

    Tudorache, Christian; O’Keefe, Robyn A.; Benfey, Tillmann J.

    2011-01-01

    Several measures have been developed to quantify swimming performance to understand various aspects of ecology and behaviour, as well as to help design functional applications for fishways and aquaculture. One of those measures, the optimal swimming speed, is the speed at which the cost of transport (COT) is minimal, where COT is defined as the cost of moving unit mass over unit distance. The experimental protocol to determine the optimal swimming speed involves forced-swimming in a flume or ...

  10. Long-term rearing of Arctic charr Salvelinus alpinus under different salinity regimes at constant temperature.

    Science.gov (United States)

    Arnason, T; Gunnarsson, S; Imsland, A K; Thorarensen, H; Smáradóttir, H; Steinarsson, A; Gústavsson, A; Johansson, M; Björnsson, B Th

    2014-10-01

    Arctic charr Salvelinus alpinus of the Hólar strain (mean ± s.e. body mass = 152·1 ± 3·1 g) were reared at four different salinity regimes at a constant temperature of 7·4° C. Two groups were given a three-month acclimation in salinity 18 before the salinity was increased to either 25 or 29 (groups called A25 and A29), and two groups were reared in salinities 25 or 29 over the full experimental period of 409 days (groups called F25 and F29). In the first 3 months, the A25 and A29 groups had the highest growth rates. By October 2011, there were no significant differences (two-way nested ANOVA, P > 0·05) in the mean body masses among A25, F25 and F29 (c. 1450 g), whereas A29 had a lower mean mass (1282 g). The growth in the last period from October 2011 to January 2012 was reduced by sexual maturation in the highest salinity regimes (A29 and F29), whereas fish in groups A25 and F25 showed high growth throughout the study. Males in all salinity groups had higher growth rates than females for the most part of the study, but the divergence between the sexes was most pronounced in the highest salinity regimes. All salinity groups showed distinct changes in Na(+) , K(+) -ATPase activity, with high activity in spring and summer, and lower activity in the autumn. Plasma sodium (Na(+) ) levels were stable indicating that none of the experimental groups had problems in maintaining hydromineral balance during the study. While plasma leptin levels were not affected by salinity regimes, it was noted that these levels were 13-30% higher in fish with empty guts compared with those having food in their gut at the time of sampling. This suggests a link between leptin levels and food intake, indicating that this hormone may play a role in food intake and energy allocation in fishes. PMID:25053158

  11. Differences in organotin accumulation in relation to life history in the white-spotted charr Salvelinus leucomaenis

    International Nuclear Information System (INIS)

    Research highlights: → Otolith Sr:Ca ratios in sea-run type were higher than those in freshwater-residents. → TBT and TPT concentrations in sea-run type were higher than those in freshwater-residents. → Sea-run type have higher risk of TBT and TPT than freshwater-residents in white-spotted charr. - Abstract: To examine the accumulation pattern of organotins (OTs) in relation to the migration of diadromous fish, tributyltin (TBT) and triphenyltin (TPT) and their derivatives were determined in the muscle tissue of both sea-run (anadromous) and freshwater-resident (nonanadromous) types of the white-spotted charr Salvelinus leucomaenis. Ontogenic changes in otolith strontium (Sr) and calcium (Ca) concentrations were examined along life history transect to discriminate migration type. Mean Sr:Ca ratio from the core to the edge of the otolith in sea-run individuals was significantly higher than those in freshwater-resident one. There were no significant correlations in S. leucomaenis between OT accumulation and various biological characteristics. It is noteworthy that TBT and TPT concentrations in sea-run type were significantly higher than those in freshwater-resident individuals, although they are both of the same species. These results suggest that sea-run S. leucomaenis have a higher ecological risk of OT exposure than freshwater-residents during their life histories.

  12. Preference and avoidance pH of brook trout Salvelinus fontinalis and brown trout Salmo trutta exposed to different holding pH.

    Science.gov (United States)

    Fost, B A; Ferreri, C P

    2015-08-01

    The goal of this study was to determine if short-term exposure of brook trout Salvelinus fontinalis and brown trout Salmo trutta to a lower pH than found in their source stream results in a shift in preference or avoidance pH. The lack of a shift in preference or avoidance pH of adult S. fontinalis and S. trutta suggests that these species can be held at a pH different from the source waterbody for a short period of time without altering preference or avoidance pH behaviour. PMID:26147766

  13. Chromosomal characteristics and distribution of rDNA sequences in the brook trout Salvelinus fontinalis (Mitchill, 1814).

    Science.gov (United States)

    Śliwińska-Jewsiewicka, A; Kuciński, M; Kirtiklis, L; Dobosz, S; Ocalewicz, K; Jankun, Malgorzata

    2015-08-01

    Brook trout Salvelinus fontinalis (Mitchill, 1814) chromosomes have been analyzed using conventional and molecular cytogenetic techniques enabling characteristics and chromosomal location of heterochromatin, nucleolus organizer regions (NORs), ribosomal RNA-encoding genes and telomeric DNA sequences. The C-banding and chromosome digestion with the restriction endonucleases demonstrated distribution and heterogeneity of the heterochromatin in the brook trout genome. DNA sequences of the ribosomal RNA genes, namely the nucleolus-forming 28S (major) and non-nucleolus-forming 5S (minor) rDNAs, were physically mapped using fluorescence in situ hybridization (FISH) and primed in situ labelling. The minor rDNA locus was located on the subtelo-acrocentric chromosome pair No. 9, whereas the major rDNA loci were dispersed on 14 chromosome pairs, showing a considerable inter-individual variation in the number and location. The major and minor rDNA loci were located at different chromosomes. Multichromosomal location (3-6 sites) of the NORs was demonstrated by silver nitrate (AgNO3) impregnation. All Ag-positive i.e. active NORs corresponded to the GC-rich blocks of heterochromatin. FISH with telomeric probe showed the presence of the interstitial telomeric site (ITS) adjacent to the NOR/28S rDNA site on the chromosome 11. This ITS was presumably remnant of the chromosome rearrangement(s) leading to the genomic redistribution of the rDNA sequences. Comparative analysis of the cytogenetic data among several related salmonid species confirmed huge variation in the number and the chromosomal location of rRNA gene clusters in the Salvelinus genome.

  14. A comparison of mercury biomagnification through lacustrine food webs supporting Brook Trout (Salvelinus fontinalis and other salmonid fishes

    Directory of Open Access Journals (Sweden)

    Monica LD Finley

    2016-04-01

    Full Text Available Methyl mercury (MeHg bioaccumulation in lower-trophic-level organisms and its subsequent biomagnification through food webs differs in magnitude among lakes and results in intraspecific variability of MeHg in top predator fishes. Understanding these differences is critical given the reproductive and neurotoxic effects of MeHg on fishes and their predators, including humans. In this study we characterized the food webs of five lakes in New Brunswick, Canada, supporting Brook Trout (Salvelinus fontinalis using measures of relative trophic position (δ15N and carbon sources (δ13C, determined the concentrations of MeHg in invertebrates and total Hg (THg in fishes, and quantified MeHg biomagnification from primary to tertiary consumers. Methyl Hg and THg concentrations were highest in biota from lakes with lower pH. The trophic magnification slopes (TMS; log Hg versus δ15N varied significantly among lakes (0.12-0.20; ANCOVA, p=0.031. When combined with data from other salmonid lakes in temperate and Arctic Canada (n=36, among-system variability in TMS was best, but weakly, positively predicted by aqueous total phosphorous (p = 0.028, R2adj = 0.109. These results suggest that lake productivity directly or indirectly influences the biomagnification of MeHg through diverse food webs supporting salmonids.

  15. Genetic and morphological divergence in three strains of brook trout Salvelinus fontinalis commonly stocked in Lake Superior.

    Directory of Open Access Journals (Sweden)

    Garrett J McKinney

    Full Text Available Fitness related traits often show spatial variation across populations of widely distributed species. Comparisons of genetic variation among populations in putatively neutral DNA markers and in phenotypic traits susceptible to selection (QST FST analysis can be used to determine to what degree differentiation among populations can be attributed to selection or genetic drift. Traditionally, QST FST analyses require a large number of populations to achieve sufficient statistical power; however, new methods have been developed that allow QST FST comparisons to be conducted on as few as two populations if their pedigrees are informative. This study compared genetic and morphological divergence in three strains of brook trout Salvelinus fontinalis that were historically or currently used for stocking in the Lake Superior Basin. Herein we examined if morphological divergence among populations showed temporal variation, and if divergence could be attributed to selection or was indistinguishable from genetic drift. Multivariate QST FST analysis showed evidence for divergent selection between populations. Univariate analyses suggests that the pattern observed in the multivariate analyses was largely driven by divergent selection for length and weight, and moreover by divergence between the Assinica strain and each of the Iron River and Siskiwit strains rather than divergent selection between each population pair. While it could not be determined if divergence was due to natural selection or inadvertent artificial selection in hatcheries, selected differences were consistent with patterns of domestication commonly found in salmonids.

  16. Breaking the speed limit--comparative sprinting performance of brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta)

    Science.gov (United States)

    Castro-Santos, Theodore; Sanz-Ronda, Francisco Javier; Ruiz-Legazpi, Jorge

    2013-01-01

    Sprinting behavior of free-ranging fish has long been thought to exceed that of captive fish. Here we present data from wild-caught brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta), volitionally entering and sprinting against high-velocity flows in an open-channel flume. Performance of the two species was nearly identical, with the species attaining absolute speeds > 25 body lengths·s−1. These speeds far exceed previously published observations for any salmonid species and contribute to the mounting evidence that commonly accepted estimates of swimming performance are low. Brook trout demonstrated two distinct modes in the relationship between swim speed and fatigue time, similar to the shift from prolonged to sprint mode described by other authors, but in this case occurring at speeds > 19 body lengths·s−1. This is the first demonstration of multiple modes of sprint swimming at such high swim speeds. Neither species optimized for distance maximization, however, indicating that physiological limits alone are poor predictors of swimming performance. By combining distributions of volitional swim speeds with endurance, we were able to account for >80% of the variation in distance traversed by both species.

  17. Sibship reconstruction for inferring mating systems, dispersal and effective population size in headwater brook trout (Salvelinus fontinalis) populations

    Science.gov (United States)

    Kanno, Yoichiro; Vokoun, Jason C.; Letcher, Benjamin H.

    2011-01-01

    Brook trout Salvelinus fontinalis populations have declined in much of the native range in eastern North America and populations are typically relegated to small headwater streams in Connecticut, USA. We used sibship reconstruction to infer mating systems, dispersal and effective population size of resident (non-anadromous) brook trout in two headwater stream channel networks in Connecticut. Brook trout were captured via backpack electrofishing using spatially continuous sampling in the two headwaters (channel network lengths of 4.4 and 7.7 km). Eight microsatellite loci were genotyped in a total of 740 individuals (80–140 mm) subsampled in a stratified random design from all 50 m-reaches in which trout were captured. Sibship reconstruction indicated that males and females were both mostly polygamous although single pair matings were also inferred. Breeder sex ratio was inferred to be nearly 1:1. Few large-sized fullsib families (>3 individuals) were inferred and the majority of individuals were inferred to have no fullsibs among those fish genotyped (family size = 1). The median stream channel distance between pairs of individuals belonging to the same large-sized fullsib families (>3 individuals) was 100 m (range: 0–1,850 m) and 250 m (range: 0–2,350 m) in the two study sites, indicating limited dispersal at least for the size class of individuals analyzed. Using a sibship assignment method, the effective population size for the two streams was estimated at 91 (95%CI: 67–123) and 210 (95%CI: 172–259), corresponding to the ratio of effective-to-census population size of 0.06 and 0.12, respectively. Both-sex polygamy, low variation in reproductive success, and a balanced sex ratio may help maintain genetic diversity of brook trout populations with small breeder sizes persisting in headwater channel networks.

  18. Fine-scale population structure and riverscape genetics of brook trout (Salvelinus fontinalis) distributed continuously along headwater channel networks

    Science.gov (United States)

    Kanno, Yoichiro; Vokoun, Jason C.; Letcher, Benjamin H.

    2011-01-01

    Linear and heterogeneous habitat makes headwater stream networks an ideal ecosystem in which to test the influence of environmental factors on spatial genetic patterns of obligatory aquatic species. We investigated fine-scale population structure and influence of stream habitat on individual-level genetic differentiation in brook trout (Salvelinus fontinalis) by genotyping eight microsatellite loci in 740 individuals in two headwater channel networks (7.7 and 4.4 km) in Connecticut, USA. A weak but statistically significant isolation-by-distance pattern was common in both sites. In the field, many tagged individuals were recaptured in the same 50-m reaches within a single field season (summer to fall). One study site was characterized with a hierarchical population structure, where seasonal barriers (natural falls of 1.5–2.5 m in height during summer base-flow condition) greatly reduced gene flow and perceptible spatial patterns emerged because of the presence of tributaries, each with a group of genetically distinguishable individuals. Genetic differentiation increased when pairs of individuals were separated by high stream gradient (steep channel slope) or warm stream temperature in this site, although the evidence of their influence was equivocal. In a second site, evidence for genetic clusters was weak at best, but genetic differentiation between individuals was positively correlated with number of tributary confluences. We concluded that the population-level movement of brook trout was limited in the study headwater stream networks, resulting in the fine-scale population structure (genetic clusters and clines) even at distances of a few kilometres, and gene flow was mitigated by ‘riverscape’ variables, particularly by physical barriers, waterway distance (i.e. isolation-by-distance) and the presence of tributaries.

  19. Effective number of breeders, effective population size and their relationship with census size in an iteroparous species, Salvelinus fontinalis.

    Science.gov (United States)

    Ruzzante, Daniel E; McCracken, Gregory R; Parmelee, Samantha; Hill, Kristen; Corrigan, Amelia; MacMillan, John; Walde, Sandra J

    2016-01-27

    The relationship between the effective number of breeders (Nb) and the generational effective size (Ne) has rarely been examined empirically in species with overlapping generations and iteroparity. Based on a suite of 11 microsatellite markers, we examine the relationship between Nb, Ne and census population size (Nc) in 14 brook trout (Salvelinus fontinalis) populations inhabiting 12 small streams in Nova Scotia and sampled at least twice between 2009 and 2015. Unbiased estimates of Nb obtained with individuals of a single cohort, adjusted on the basis of age at first maturation (α) and adult lifespan (AL), were from 1.66 to 0.24 times the average estimates of Ne obtained with random samples of individuals of mixed ages (i.e. [Formula: see text]). In turn, these differences led to adjusted Ne estimates that were from nearly five to 0.7 times the estimates derived from mixed-aged individuals. These differences translate into the same range of variation in the ratio of effective to census population size [Formula: see text] within populations. Adopting [Formula: see text] as the more precise and unbiased estimates, we found that these brook trout populations differ markedly in their effective to census population sizes (range approx. 0.3 to approx. 0.01). Using AgeNe, we then showed that the variance in reproductive success or reproductive skew varied among populations by a factor of 40, from Vk/k ≈ 5 to 200. These results suggest wide differences in population dynamics, probably resulting from differences in productivity affecting the intensity of competition for access to mates or redds, and thus reproductive skew. Understanding the relationship between Ne, Nb and Nc, and how these relate to population dynamics and fluctuations in population size, are important for the design of robust conservation strategies in small populations with overlapping generations and iteroparity. PMID:26817773

  20. Growth Performance, Food Intake and Feed Converison Ratios in Rainbow (Onchorynchus mykiss) and Brook Trout (Salvelinus fontinalis) Reared as a Single and Mixed Species

    OpenAIRE

    Okumuş, İbrahim; ÇELİKKALE, M. Salih; KURTOĞLU, İ. Zeki; BAŞÇINAR, Nadir

    1998-01-01

    Growth performances, daily food consumption and feed conversion ratios of rainbow (Onchorynchus mykiss) and brook trout (Salvelinus fontinalis) reared as single and mixed species were compared. During the experimental period, which lasted for about a growing season (December - June, 217 days), mean % weight increment of single species brook trout group were maximum (from 18.2 to 165.6 g), followed by mixed rainbow (26.8 to 241.6 g) and brook trout (17.0 to 151.8 g), and single species rainb...

  1. Morphological, ecological and behavioural differentiation of sympatric profundal and pelagic Arctic charr (Salvelinus alpinus) in Loch Dughaill Scotland

    OpenAIRE

    Hooker, O.E.; Barry, J; Van Leeuwen, T. E.; Lyle, A.; Newton, Jason; Cunningham, P.; Adams, C.E.

    2016-01-01

    Phenotypic variation in populations of fishes that inhabit postglacial lakes is often associated with trophic specialisations. A common sympatric foraging divergence seen in Arctic charr is into either plankton or littoral-zoobenthos feeding specialisms. In this study, we report a sympatric polymorphic Arctic charr population which is not centred on this divergence but instead manifests as a plankton (pelagic)—profundal zoobenthos foraging specialisms. The head shape of profundal fish was rou...

  2. Astaxanthin and its metabolites idoxanthin and crustaxanthin in flesh, skin, and gonads of sexually immature and maturing Arctic charr (Salvelinus alpinus (L.)).

    Science.gov (United States)

    Bjerkeng, B; Hatlen, B; Jobling, M

    2000-03-01

    Carotenoid compositions of the flesh, skin, and ovaries were determined in sexually maturing and immature Arctic charr (Salvelinus alpinus) fed diets supplemented with astaxanthin (optical isomer ratio (3S,3'S):(3R,3'S; meso):(3R,3'R); 1:2:1). Astaxanthin comprised 64-79% of the flesh carotenoids, and the 3',4'-cis and 3',4'-trans glycolic isomers of idoxanthin, present in a 1:1 ratio, represented 20-35%. The flesh of the sexually maturing charr contained relatively more idoxanthin than that of sexually immature fish (20 vs 35% of total carotenoids), possibly being indicative of a higher metabolic turnover of astaxanthin in the latter. The relative proportions of flesh carotenoids were unaffected by sex. The relative carotenoid composition of ovaries was similar in sexually maturing and immature females. The 3',4'-cis and 3',4'-trans glycolic isomers of idoxanthin (ratio 0.7:1) were the major carotenoids (56% of total), followed by crustaxanthin (20%), and astaxanthin comprised less than 5% of ovarian carotenoids. Three glycolic isomers of crustaxanthin were detected (3,4,3',4'-di-cis-:3,4-cis-3',4'-trans-:3,4,3',4'-di-trans-glycolic isomer ratio 2.6:3.1:1) in the ovaries. Sex and maturity status had no apparent effect on the relative composition of skin carotenoids. The skin carotenoids consisted mainly of diesters (82-87% of total carotenoids) and monoesters (7-13% of total carotenoids). Saponification revealed that astaxanthin comprised 85% and idoxanthin 10% of total carotenoids, and minor amounts of tunaxanthin-, lutein-, and zeaxanthin-like metabolites were also present. Maturity status seems to be more important than sex in determining the relative carotenoid composition of the tissues of Arctic charr, with astaxanthin and its metabolites being selectively accumulated in different tissues.

  3. Innate and adaptive immune responses of Arctic charr (Salvelinus alpinus, L.) during infection with Aeromonas salmonicida subsp. achromogenes and the effect of the AsaP1 toxin.

    Science.gov (United States)

    Schwenteit, Johanna M; Breithaupt, Angele; Teifke, Jens P; Koppang, Erling O; Bornscheuer, Uwe T; Fischer, Uwe; Gudmundsdottir, Bjarnheidur K

    2013-09-01

    Aeromonas salmonicida subsp. achromogenes, the causative agent of atypical furunculosis in many fish species, secretes the toxic metalloendopeptidase AsaP1. This study aimed to analyze innate and adaptive immune parameters induced in Arctic charr (Salvelinus alpinus, L.) infected with wild type (wt) A. salmonicida subsp. achromogenes and its isogenic asaP1 deletion mutant (AsaP1-deficient). Head-kidney, liver and spleen were obtained from i.p. infected charr (wt, AsaP1-deficient), during a time schedule of 7 d post infection. Reverse transcription quantitative real-time PCR (RT-qPCR) was applied to study the expression of immune parameters: pro-inflammatory cytokines IL-1β and TNF-α; anti-inflammatory cytokine IL-10; chemokines CXCL-8 (IL-8) and CC-chemokine; the cytokines IFN-γ and IL-4/13A as tracers for Th1 and Th2 immune responses, respectively; and the cell markers CD8α and CD83. In addition, lymphoid organs were histopathologically examined at days 3 and 7 post infection, including B (IgM) and T (CD3ε) cell staining. The detected immune responses were initially driven by innate mechanisms represented by the up-regulation of pro-inflammatory cytokines and chemokines and later on by adaptive Th2 related responses cumulating in B-cell recruitment as shown by regulation of immune parameters in spleen and head-kidney, with significant differences between mutant and wt infected fish. Histological sections revealed IgM-positive cells around ellipsoid arterioles in spleen, while CD3ε positive cells were found in clusters scattered all over the section. However, histopathological differences were only detected between infected and non-infected fish, but not between AsaP1-deficient mutant and wt infected fish. This work represents the first study on innate and adaptive immune responses of Arctic charr induced by a bacterial infection. PMID:23811350

  4. Satiation meal and the effects of meal and body sizes on gastric evacuation rate in brook trout Salvelinus fontinalis fed commercial pellets.

    Science.gov (United States)

    Khan, U; Seyhan, K; Başçinar, N; Başçinar, N S

    2016-08-01

    Gastric evacuation (GE) experiments were performed on brook trout Salvelinus fontinalis fed commercial food pellets. The experiments included small fish (36 g; 15 cm total length, LT ) fed meals of 0·2, 0·4 and 0·8 g and large fish (152 g; 23 cm) fed meals of 0·8, 2·0 and 4·0 g at temperatures ranging from 15·1 to 18·2° C. The stomach contents were thereafter sampled and weighed at 3 h intervals until the first empty stomach was observed. The course of GE was examined by use of a general power function of the data that revealed that the square-root function described the GE rate (GER) by the current stomach content mass independently of original meal size. Using the square-root function, the relationship between GER and fish size was described by a power function of fish length, whereas the effect of temperature was described by a simple exponential function. GER of the commercial pellets fed to S. fontinalis could thus be described by dStdt=-0·000464L1·31e0·052TSt (g h(-1) ), where St is stomach mass (g) at time t (h), L is total fish length (cm) and T is temperature (° C). The result of this study should provide a useful tool for planning of feeding regimes in production of S. fontinalis by optimizing growth and minimizing food waste. PMID:27282124

  5. Phenotypic and genetic variation in two North American arctic charr (Salvelinus alpinus) stocks cultured in recirculating aquaculture systems

    Science.gov (United States)

    Arctic charr were obtained as eggs from two North American sources, an eastern (Fraser River, Canada) and a western (Bristol Bay, Alaska) stock. Fish from each family (n=38) were pit tagged at approximately 12 months post-hatch (eastern mean+SE=247+/-13g, western mean+SE=220+/-g) and stocked commun...

  6. Arctic charr farming

    OpenAIRE

    Brännäs, Eva; Larsson, Stefan; Saether, Björn Steinar; Siikavuopio, Sten Ivar; Thorarensen, Helgi; Sigurgeirsson, Ólafur; Jeuthe, Henrik

    2011-01-01

    The Arctic charr (Salvelinus alpinus L.) is a holarctic salmonid fish species with both landlocked and anadromous populations. In Scandinavia it is mainly found in the mountain area, but it also appears in deep and large lake further south, i.e. in the Alps. It is the northernmost freshwater fish and A. charr is generally regarded as the most cold-adapted freshwater fish. A. charr has been commercially farmed since the early 90ths and today, the total production is 3000, 2300 and 700 tonnes/y...

  7. Comparative analysis of total mercury concentrations in anadromous and non-anadromous Arctic charr (Salvelinus alpinus) from eastern Canada

    International Nuclear Information System (INIS)

    Previous research has documented that total mercury concentrations ([THg]) are lower in anadromous Arctic charr than in non-anadromous conspecifics, but the two life-history forms have rarely been studied together. Here, data from nine pairs of closely-located anadromous and non-anadromous Arctic charr populations were used to explore the impact of biological and life-history factors on individual [THg] across a range of latitudes (49–81° N) in eastern Canada. Unadjusted mean [THg] ranged from 20 to 114 ng/g wet weight (ww) in anadromous populations, and was significantly higher in non-anadromous populations, ranging from 111 to 227 ng/g ww. Within-population variations in [THg] were best explained by fish age, and were often positively related to fork-length and δ15N-inferred trophic level. Differences in [THg] were not related to differences in length-at-age (i.e., average somatic growth rate) among populations of either life-history type. Mercury concentrations were not related to site latitude in either the anadromous or non-anadromous fish. We conclude that the difference in Arctic charr [THg] with life-history type could not be explained by differences in fish age, fork-length, trophic position, or length-at-age, and discuss possible factors contributing to low mercury concentrations in anadromous, relative to freshwater, fish. - Highlights: ► Total mercury concentrations ([THg]) were measured in 9 co-located anadromous and non-anadromous Arctic charr populations. ► Mean [THg] in non-anadromous populations exceeded mean [THg] in spatially paired anadromous populations. ► Among-individual variation in [THg] was best explained by fish age. ► The lower [THg] in anadromous fish could not be explained by differences in age, fork-length, trophic level, or growth rate. ► Variations in Arctic charr [THg] were independent of latitude (49–81° N) in eastern Canada

  8. Analysis of trade-offs between threats of invasion by nonnative brook trout (Salvelinus fontinalis) and intentional isolation for native westslope cutthroat trout (Oncorhynchus clarkii lewisi)

    Science.gov (United States)

    Peterson, D.P.; Rieman, B.E.; Dunham, J.B.; Fausch, K.D.; Young, M.K.

    2008-01-01

    Native salmonid fishes often face simultaneous threats from habitat fragmentation and invasion by nonnative trout species. Unfortunately, management actions to address one may create or exacerbate the other. A consistent decision process would include a systematic analysis of when and where intentional use or removal of barriers is the most appropriate action. We developed a Bayesian belief network as a tool for such analyses. We focused on native westslope cutthroat trout (Oncorhynchus clarkii lewisi) and nonnative brook trout (Salvelinus fontinalis) and considered the environmental factors influencing both species, their potential interactions, and the effects of isolation on the persistence of local cutthroat trout populations. The trade-offs between isolation and invasion were strongly influenced by size and habitat quality of the stream network to be isolated and existing demographic linkages within and among populations. An application of the model in several sites in western Montana (USA) showed the process could help clarify management objectives and options and prioritize conservation actions among streams. The approach can also facilitate communication among parties concerned with native salmonids, nonnative fish invasions, barriers and intentional isolation, and management of the associated habitats and populations. ?? 2008 NRC.

  9. Perturbation in protein expression of the sterile salmonid hybrids between female brook trout Salvelinus fontinalis and male masu salmon Oncorhynchus masou during early spermatogenesis.

    Science.gov (United States)

    Zheng, Liang; Senda, Yoshie; Abe, Syuiti

    2013-05-01

    Most males and females of intergeneric hybrid (BM) between female brook trout (Bt) Salvelinus fontinalis and male masu salmon (Ms) Oncorhynchus masou had undeveloped gonads, with abnormal germ cell development shown by histological examination. To understand the cause of this hybrid sterility, expression profiles of testicular proteins in the BM and parental species were examined with 2-DE coupled with MALDI-TOF/TOF MS. Compared with the parental species, more than 60% of differentially expressed protein spots were down-regulated in BM. A total of 16 up-regulated and 48 down-regulated proteins were identified in BM. Up-regulated were transferrin and other somatic cell-predominant proteins, whereas down-regulated were some germ cell-specific proteins such as DEAD box RNA helicase Vasa. Other pronouncedly down-regulated proteins included tubulins and heat shock proteins that are supposed to have roles in spermatogenesis. The present findings suggest direct association of the observed perturbation in protein expression with the failure of spermatogenesis and the sterility in the examined salmonid hybrids.

  10. Influence of o'p-DDD on the physiological response to stress in Arctic charr (Salvelinus alpinus).

    Science.gov (United States)

    Jørgensen, E H; Balm, P H; Christiansen, J S; Plotitsyna, N; Ingebrigtsen, K

    2001-10-01

    Various toxicants have previously been held responsible for an impaired capacity of fish from polluted environments to elevate their cortisol levels in response to stress. In the present study we investigated the responses to stress in o'p-DDD [2-(chlorophenyl)-2-(4-chlorphenyl)-1,1-dichloroethane] exposed (given a single, oral dose of 75 mg o'p-DDD/kg fish) and unexposed Arctic charr. After o'p-DDD administration fish were left undisturbed and without being fed for 28 days, when they were subjected to an acute handling stress. At 1, 3, 7 and 23 h following stress, primary (ACTH and cortisol secretion) and secondary (plasma Cl levels and energy mobilisation) components of the stress response were monitored. As the nutritional state of wild fish may influence this potential biomarker response, the fish had been subjected to a restricted feed ration prior to o'p-DDD administration in order to obtain marked within-group variations in condition factor. No effects of o'p-DDD were observed on post-stress hormone secretion (i.e. peak post-stress plasma ACTH and cortisol levels), nor on plasma chloride levels. However, other results obtained provided evidence for a metabolic depression by o'p-DDD, witnessed by consistently lower plasma glucose levels before and after stress in these contaminated fish. This may be related to the finding that during the 30-day period between o'p-DDD administration and stress treatment, toxicant treated fish lost less weight in comparison to their sham-treated counterparts. Nutritional state did not appear to influence the performance of the charr in the present experiment, as correlations between the parameters measured and condition factor or lipid contents on an individual basis in all cases turned out non significant. Overall, the results contrast with those of previous in vivo and in vitro studies on fish, which concluded that comparable headkidney o'p-DDD levels impaired interrenal steroidogenesis. Although we conclude that the effects

  11. Ontogenetic dynamics of infection with Diphyllobothrium spp. cestodes in sympatric Arctic charr Salvelinus alpinus (L.) and brown trout Salmo trutta L.

    Science.gov (United States)

    Henrickson, Eirik H.; Knudsen, Rune; Kristoffersen, Roar; Kuris, Armand M.; Lafferty, Kevin D.; Siwertsson, Anna; Amundsen, Per-Arne

    2015-01-01

    The trophic niches of Arctic charr and brown trout differ when the species occur in sympatry. Their trophically transmitted parasites are expected to reflect these differences. Here, we investigate how the infections of Diphyllobothrium dendriticum and D. ditremum differ between charr and trout. These tapeworms use copepods as their first intermediate hosts and fish can become infected as second intermediate hosts by consuming either infected copepods or infected fish. We examined 767 charr and 368 trout for Diphyllobothrium plerocercoids in a subarctic lake. The prevalence of D. ditremum was higher in charr (61.5%) than in trout, (39.5%), but the prevalence of D. dendriticum was higher in trout (31.2%) than in charr (19.3%). Diphyllobothrium spp. intensities were elevated in trout compared to charr, particularly for D. dendriticum. Large fish with massive parasite burdens were responsible for the high Diphyllobothrium spp. loads in trout. We hypothesize that fish prey may be the most important source for the Diphyllobothrium spp. infections in trout, whereas charr predominantly acquire Diphyllobothrium spp. by feeding on copepods. Our findings support previous suggestions that the ability to establish in a second piscine host is greater for D. dendriticum than for D. ditremum.

  12. Basal mercury concentrations and biomagnification rates in freshwater and marine food webs: Effects on Arctic charr (Salvelinus alpinus) from eastern Canada

    Energy Technology Data Exchange (ETDEWEB)

    Velden, S. van der, E-mail: sdorn@uwaterloo.ca [Department of Biology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1 (Canada); Dempson, J.B. [Fisheries and Oceans Canada, St. John' s, Newfoundland and Labrador, Canada, A1C 5X1 (Canada); Evans, M.S. [Environment Canada, Saskatoon, Saskatchewan, Canada, S7N 3H5 (Canada); Muir, D.C.G. [Environment Canada, Burlington, Ontario, Canada, L7R 4A6 (Canada); Power, M., E-mail: m3power@uwaterloo.ca [Department of Biology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1 (Canada)

    2013-02-01

    Patterns of total Hg (THg) and methyl Hg (MeHg) biomagnification were investigated in six pairs of co-located lacustrine and marine food webs supporting a common predator, Arctic charr. Mercury biomagnification rates (the slope of log Hg concentration versus δ{sup 15}N-inferred trophic level) did not differ significantly between the two feeding habitats for either THg or MeHg, but THg and MeHg concentrations at the base of the food web were higher in the lacustrine environment than in the marine environment. The proportion of THg as MeHg was related to trophic level, and the relationship was statistically similar in the lacustrine and marine habitats. The biomagnification rate of MeHg exceeded that of THg in both habitats. We conclude that the known difference in Hg concentration between anadromous and non-anadromous Arctic charr is driven by differential Hg concentrations at the base of the lacustrine and marine foodwebs, and not by differential biomagnification rates. - Highlights: ► Concentrations of total mercury ([THg]) and methylmercury ([MeHg]) were measured in 6 paired lacustrine and marine food webs. ► Biomagnification rates (slopes of [THg] or [MeHg] versus δ{sup 15}N-inferred trophic level) were similar in the two habitat types. ► Mercury concentrations at the base of the food web were higher in lacustrine than in marine food webs. ► The percentage of methylated mercury increased with trophic level similarly in the two habitat types. ► The biomagnification rate of MeHg exceeded that of THg in both habitats.

  13. Basal mercury concentrations and biomagnification rates in freshwater and marine food webs: Effects on Arctic charr (Salvelinus alpinus) from eastern Canada

    International Nuclear Information System (INIS)

    Patterns of total Hg (THg) and methyl Hg (MeHg) biomagnification were investigated in six pairs of co-located lacustrine and marine food webs supporting a common predator, Arctic charr. Mercury biomagnification rates (the slope of log Hg concentration versus δ15N-inferred trophic level) did not differ significantly between the two feeding habitats for either THg or MeHg, but THg and MeHg concentrations at the base of the food web were higher in the lacustrine environment than in the marine environment. The proportion of THg as MeHg was related to trophic level, and the relationship was statistically similar in the lacustrine and marine habitats. The biomagnification rate of MeHg exceeded that of THg in both habitats. We conclude that the known difference in Hg concentration between anadromous and non-anadromous Arctic charr is driven by differential Hg concentrations at the base of the lacustrine and marine foodwebs, and not by differential biomagnification rates. - Highlights: ► Concentrations of total mercury ([THg]) and methylmercury ([MeHg]) were measured in 6 paired lacustrine and marine food webs. ► Biomagnification rates (slopes of [THg] or [MeHg] versus δ15N-inferred trophic level) were similar in the two habitat types. ► Mercury concentrations at the base of the food web were higher in lacustrine than in marine food webs. ► The percentage of methylated mercury increased with trophic level similarly in the two habitat types. The biomagnification rate of MeHg exceeded that of THg in both habitats

  14. Incipient speciation through niche expansion: an example from the Arctic charr in a subarctic lake

    OpenAIRE

    Knudsen, Rune; Klemetsen, Anders; Amundsen, Per-Arne; Hermansen, Bjørn

    2006-01-01

    Two reproductive isolated morphs of Arctic charr (Salvelinus alpinus), termed profundal and littoral charr according to their different spawning habitats, co-occur in the postglacial lake Fjellfrøsvatn in North Norway. All profundal charr live in deep water their entire life and have a maximum size of 14 cm, while the littoral charr grow to 40 cm. Some small and young littoral charr move to the profundal zone in an ontogenetic habitat shift in the ice-free season and the rest of the populatio...

  15. Genome evolution in the fish family salmonidae: generation of a brook charr genetic map and comparisons among charrs (Arctic charr and brook charr with rainbow trout

    Directory of Open Access Journals (Sweden)

    Moghadam Hooman K

    2011-07-01

    species of charr (genus Salvelinus and a trout (genus Oncorhynchus have identified that linkage group arm arrangements are largely retained among these species. Previous studies have revealed that up to 7 regions of high duplicate marker retention occur between Salmo species (i.e., Atlantic salmon and brown trout and rainbow trout, with 5 of these regions exhibiting higher levels of pseudolinkage. Pseudolinkage was detected in the charr species (i.e., BC-1/21, AC-12/27, AC-6/23, = RT-2p/29q, RT-12p/16p, and RT-27p/31p, respectively consistent with three of the five 'salmonid-specific' pseudolinkage regions. Chromosome arms with the highest number of duplicated markers in rainbow trout are the linkage group arms with the highest retention of duplicated markers in both charr species.

  16. Aroclor 1254 exposure reduces disease resistance and innate immune responses in fasted arctic charr

    Science.gov (United States)

    Maule, A.G.; Jorgensen, E.H.; Vijayan, M.M.; Killie, J.-E.A.

    2005-01-01

    To examine the immunological impacts of polychlorinated biphenyls (PCBs) in an environmentally relevant way, we orally contaminated Arctic charr (Salvelinus alpinus) with Aroclor 1254. After contamination, fish were either fed (0 and 100 mg Aroclor 1254 kg-1 fish wt) or fasted (0, 1, 10, and 100 mg kg-1) to mimic cycles of feeding-fasting experienced by Arctic animals. After four months, PCB concentrations in muscle were the same in fasted and fed fish; however, PCBs in kidneys of fed fish were 33 to 50% of those in fasted fish. Arctic charr were exposed to Aeromonas salmonicida, the bacteria responsible for furunculosis, by cohabitation with infected conspecifics. Fasted fish had a significant trend toward lower survival with higher dose of PCBs - from 68% in controls to 48% in treatment involving 100 mg kg-1. Independent of PCB contamination, fed fish had the lowest survival; we attribute this to stress associated with establishing and maintaining feeding hierarchies. A significant decrease in the activity of lysozyme was observed in skin mucus, as was hemagglutination ability of a putative rhamnose lectin in fasted, but not in fed, PCB-treated fish. These results demonstrate the immunosuppressive effects of PCBs on Arctic charr, and they illustrate the importance of considering environmentally relevant nutritional status in ecotoxicological studies.

  17. PCB disruption of the hypothalamus-pituitary-interrenal axis involves brain glucocorticoid receptor downregulation in anadromous Arctic charr

    Science.gov (United States)

    Aluru, N.; Jorgensen, E.H.; Maule, A.G.; Vijayan, M.M.

    2004-01-01

    We examined whether brain glucocorticoid receptor (GR) modulation by polychlorinated biphenyls (PCBs) was involved in the abnormal cortisol response to stress seen in anadromous Arctic charr (Salvelinus alpinus). Fish treated with Aroclor 1254 (0, 1, 10, and 100 mg/kg body mass) were maintained for 5 mo without feeding in the winter to mimic their seasonal fasting cycle, whereas a fed group with 0 and 100 mg/kg Aroclor was maintained for comparison. Fasting elevated plasma cortisol levels and brain GR content but depressed heat shock protein 90 (hsp90) and interrenal cortisol production capacity. Exposure of fasted fish to Aroclor 1254 resulted in a dose-dependent increase in brain total PCB content. This accumulation in fish with high PCB dose was threefold higher in fasted fish compared with fed fish. PCBs depressed plasma cortisol levels but did not affect in vitro interrenal cortisol production capacity in fasted charr. At high PCB dose, the brain GR content was significantly lower in the fasted fish and this corresponded with a lower brain hsp70 and hsp90 content. The elevation of plasma cortisol levels and upregulation of brain GR content may be an important adaptation to extended fasting in anadromous Arctic charr, and this response was disrupted by PCBs. Taken together, the hypothalamus-pituitary- interrenal axis is a target for PCB impact during winter emaciation in anadromous Arctic charr.

  18. Quantification of 15 bile acids in lake charr feces by ultra-high performance liquid chromatography–tandem mass spectrometry

    Science.gov (United States)

    Li, Ke; Buchinger, Tyler J.; Bussy, Ugo; Fissette, Skye D; Johnson, Nicholas; Li, Weiming

    2015-01-01

    Many fishes are hypothesized to use bile acids (BAs) as chemical cues, yet quantification of BAs in biological samples and the required methods remain limited. Here, we present an UHPLC–MS/MS method for simultaneous, sensitive, and rapid quantification of 15 BAs, including free, taurine, and glycine conjugated BAs, and application of the method to fecal samples from lake charr (Salvelinus namaycush). The analytes were separated on a C18 column with acetonitrile–water (containing 7.5 mM ammonium acetate and 0.1% formic acid) as mobile phase at a flow rate of 0.25 mL/min for 12 min. BAs were monitored with a negative electrospray triple quadrupole mass spectrometer (Xevo TQ-S™). Calibration curves of 15 BAs were linear over the concentration range of 1.00–5,000 ng/mL. Validation revealed that the method was specific, accurate, and precise. The method was applied to quantitative analysis of feces extract of fry lake charr and the food they were eating. The concentrations of analytes CA, TCDCA, TCA, and CDCA were 242.3, 81.2, 60.7, and 36.2 ng/mg, respectively. However, other taurine conjugated BAs, TUDCA, TDCA, and THDCA, were not detected in feces of lake charr. Interestingly, TCA and TCDCA were detected at high concentrations in food pellets, at 71.9 and 38.2 ng/mg, respectively. Application of the method to feces samples from lake charr supported a role of BAs as chemical cues, and will enhance further investigation of BAs as chemical cues in other fish species.

  19. Biological and life-history factors affecting total mercury concentrations in Arctic charr from Heintzelman Lake, Ellesmere Island, Nunavut

    Energy Technology Data Exchange (ETDEWEB)

    Velden, Shannon van der, E-mail: sdorn@sciborg.uwaterloo.ca [Department of Biology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 (Canada); Reist, James D.; Babaluk, John A. [Freshwater Institute, Fisheries and Oceans Canada, Winnipeg, Manitoba, Canada R3T 2N6 (Canada); Power, Michael, E-mail: m3power@sciborg.uwaterloo.ca [Department of Biology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 (Canada)

    2012-09-01

    A snapshot sample of Arctic charr (Salvelinus alpinus) from Heintzelman Lake (81 Degree-Sign 42 Prime N, 66 Degree-Sign 56 Prime W), Ellesmere Island, Canada was used to elucidate the biological and life-history factors potentially influencing individual total mercury (THg) concentrations. Migratory history was significant, with anadromous fish having a lower mean THg concentration (64 {mu}g/kg ww) than the non-anadromous Arctic charr (117 {mu}g/kg ww). The increase in individual THg concentration with age was shown to be independent of length-at-age when large and small individuals within the same age groups were compared. Similarly, the diets of individual Arctic charr were comparable regardless of size, and there was no apparent ontogenetic shift in diet that could explain differences in length-at-age or THg concentration among fast- and slow-growing groups of fish (i.e., fish of the same age but differing sizes). Maturity state was also not related to THg concentration, but appears to be related to differences in length-at-age, with slow-growing fish allocating more energy to reproduction than fast-growing conspecifics. The differences in THg concentration among individual Arctic charr were best explained by fish age. We suggest that the increase in mercury concentration with age can be altered by a shift in diet (e.g., to piscivory) or habitat (e.g., anadromy), but is otherwise unaffected by changes in size or length-at-age. -- Highlights: Black-Right-Pointing-Pointer Total mercury concentrations ([THg]) were measured in Arctic charr from a single lake in the Canadian high Arctic. Black-Right-Pointing-Pointer Anadromous Arctic charr had a significantly lower mean [THg] (64 {mu}g/kg ww) than the non-anadromous fish (117 {mu}g/kg ww). Black-Right-Pointing-Pointer Length-at-age (i.e., average somatic growth rate) was not related to mean [THg] when same-age groups were compared. Black-Right-Pointing-Pointer Prey resource use, determined by {delta}{sup 13}C and

  20. Biological and life-history factors affecting total mercury concentrations in Arctic charr from Heintzelman Lake, Ellesmere Island, Nunavut

    International Nuclear Information System (INIS)

    A snapshot sample of Arctic charr (Salvelinus alpinus) from Heintzelman Lake (81°42′N, 66°56′W), Ellesmere Island, Canada was used to elucidate the biological and life-history factors potentially influencing individual total mercury (THg) concentrations. Migratory history was significant, with anadromous fish having a lower mean THg concentration (64 μg/kg ww) than the non-anadromous Arctic charr (117 μg/kg ww). The increase in individual THg concentration with age was shown to be independent of length-at-age when large and small individuals within the same age groups were compared. Similarly, the diets of individual Arctic charr were comparable regardless of size, and there was no apparent ontogenetic shift in diet that could explain differences in length-at-age or THg concentration among fast- and slow-growing groups of fish (i.e., fish of the same age but differing sizes). Maturity state was also not related to THg concentration, but appears to be related to differences in length-at-age, with slow-growing fish allocating more energy to reproduction than fast-growing conspecifics. The differences in THg concentration among individual Arctic charr were best explained by fish age. We suggest that the increase in mercury concentration with age can be altered by a shift in diet (e.g., to piscivory) or habitat (e.g., anadromy), but is otherwise unaffected by changes in size or length-at-age. -- Highlights: ► Total mercury concentrations ([THg]) were measured in Arctic charr from a single lake in the Canadian high Arctic. ► Anadromous Arctic charr had a significantly lower mean [THg] (64 μg/kg ww) than the non-anadromous fish (117 μg/kg ww). ► Length-at-age (i.e., average somatic growth rate) was not related to mean [THg] when same-age groups were compared. ► Prey resource use, determined by δ13C and δ15N isotopes and gut contents, was similar among fast- and slow-growing fish. ► Maturity state was not related to [THg], but the slow-growing group

  1. Effect of acidic lake water on survival of aurora trout (Salvelinus fontinalis) embryos and alevins

    Energy Technology Data Exchange (ETDEWEB)

    Snucins, E.J.; Liimatainen, V.A.; Gale, P.A.

    1988-01-01

    During the 1960s the aurora trout, a rare color variant of the brook trout, disappeared from its native waters in northeastern Ontario. Its disappearance was attributed to acidification of the waters by atmospheric deposition of industrial emissions from metal smelters at Sudbury, Ontario. Recently, water quality in the Sudbury area has improved due to emission reductions. These experiments were designed to assess the toxicity of current water quality in the native lakes of aurora trout. During May 1984, hatchery-reared aurora trout alevins were held for 4 days in 3 of their native lakes (Whiligig, Whitepine and Wilderness with pH 4.5-4.8) and a control lake, Regan Lake (pH 6.5), and survival rates were assessed. In a second bioassay, embryos and alevins were buried in the substrate at 3 groundwater upwelling sites, and survival rates were assessed. The final test involved a 14-day exposure of groundwater-reared fish to ambient conditions.

  2. DETECTION OF RENIBACTERIUM SALMONINARUM IN TISSUE OF BROOK TROUT (SALVELINUS FONTINALIS BY NESTED RT–PCR

    Directory of Open Access Journals (Sweden)

    Irena Vardić

    2007-01-01

    Full Text Available Pathogenic bacterium Renibacterium salmoninarum causes kidney disease with high mortality rate and considerable economic losses in salmonid farming. Thus, application of fast and sensitive method for R. salmoninarum diagnosis is of great importance. This paper describes detection of R. salmoninarum in brook trout tissue with gross clinical signs of disease by nested RT–PCR. Determination of partial sequence of bacterial msa gene was done prior to comparison with similar sequences from different R. salmoninarum isolates. Nested RT–PCR proved to be a rapid and valuable diagnostic tool for R. salmoninarum detection, and sequence analysis confirmed previously reported genetic uniformity of this bacteria

  3. Does the introduced brook trout ( Salvelinus fontinalis) affect growth of the native brown trout ( Salmo trutta)?

    Science.gov (United States)

    Korsu, Kai; Huusko, Ari; Muotka, Timo

    2009-03-01

    Non-native brook trout have become widely established in North European streams. We combined evidence from an artificial-stream experiment and drainage-scale field surveys to examine whether brook trout suppressed the growth of the native brown trout (age 0 to age 2). Our experimental results demonstrated that brown trout were unaffected by the presence of brook trout but that brook trout showed reduced growth in the presence of brown trout. However, the growth reduction only appeared in the experimental setting, indicating that the reduced spatial constraint of the experimental system may have forced the fish to unnaturally intense interactions. Indeed, in the field, no effect of either species on the growth of the putative competitor was detected. These results caution against uncritical acceptance of findings from small-scale experiments because they rarely scale up to more complex field situations. This and earlier work suggest that the establishment of brook trout in North European streams has taken place mainly because of the availability of unoccupied (or underutilized) niche space, rather than as a result of species trait combinations or interspecific competition per se.

  4. Mercury and methylmercury concentrations in high altitude lakes and fish (Arctic charr) from the French Alps related to watershed characteristics.

    Science.gov (United States)

    Marusczak, Nicolas; Larose, Catherine; Dommergue, Aurélien; Paquet, Serge; Beaulne, Jean-Sébastien; Maury-Brachet, Régine; Lucotte, Marc; Nedjai, Rachid; Ferrari, Christophe P

    2011-04-15

    Total mercury (THg) and methylmercury (MeHg) concentrations were measured in the muscle of Arctic charr (Salvelinus alpinus) and in the water column of 4 lakes that are located in the French Alps. Watershed characteristics were determined (6 coverage classes) for each lake in order to evaluate the influence of watershed composition on mercury and methylmercury concentrations in fish muscle and in the water column. THg and MeHg concentrations in surface water were relatively low and similar among lakes and watershed characteristics play a major role in determining water column Hg and MeHg levels. THg muscle concentrations for fish with either a standardized length of 220mm, a standardized age of 5 years or for individualuals did not exceed the 0.5mg kg(-1) fish consumption advisory limit established for Hg by the World Health Organization (WHO, 1990). These relatively low THg concentrations can be explained by watershed characteristics, which lead to short Hg residence time in the water column, and also by the short trophic chain that is characteristic of mountain lakes. Growth rate did not seem to influence THg concentrations in fish muscles of these lakes and we observed no relationship between fish Hg concentrations and altitude. This study shows that in the French Alps, high altitude lakes have relatively low THg and MeHg concentrations in both the water column and in Arctic charr populations. Therefore, Hg does not appear to present a danger for local populations and the fishermen of these lakes.

  5. Water quality in recirculating aquaculture systems (ras) for arctic charr (salvelinus alpinus L.) culture.

    OpenAIRE

    Isla Molleda , M.

    2008-01-01

    Recirculating aquaculture systems (RAS) for fish culture have been used for more than three decades. The interest in RAS is due to their have advantages such as greatly reduced land and water requirements in places where the water resources are limited; but the RAS have also disadvantages like the deterioration of the water quality if the water treatment processes within the system are not controlled properly. The water quality problems in RAS were associated with low DO and high fish waste m...

  6. Reproductive behaviour and sex trait allocations in an external fertilizer – the Charr (Salvelinus alpinus)

    OpenAIRE

    Figenschou, Lars

    2010-01-01

    This thesis illuminates several aspects of mate choice and sexual selection in a species with external fertilization and no parental care. At a general level we have contributed to the basic framework within evolutionary biology and ecology and at a more specific level, as the proximate mechanisms controlling the associations between immune response, parasite intensities and traits indicative of sperm quality are not straightforward, we examined the effect of increased immunological activity ...

  7. Differentiation at the MHCIIα and Cath2 loci in sympatric Salvelinus alpinus resource morphs in Lake Thingvallavatn.

    Directory of Open Access Journals (Sweden)

    Kalina H Kapralova

    Full Text Available Northern freshwater fish may be suitable for the genetic dissection of ecological traits because they invaded new habitats after the last ice age (∼10.000 years ago. Arctic charr (Salvelinus alpinus colonizing streams and lakes in Iceland gave rise to multiple populations of small benthic morphotypes, often in sympatry with a pelagic morphotype. Earlier studies have revealed significant, but subtle, genetic differentiation between the three most common morphs in Lake Thingvallavatn. We conducted a population genetic screen on four immunological candidate genes Cathelicidin 2 (Cath2, Hepcidin (Hamp, Liver expressed antimicrobial peptide 2a (Leap-2a, and Major Histocompatibility Complex IIα (MHCIIα and a mitochondrial marker (D-loop among the three most common Lake Thingvallavatn charr morphs. Significant differences in allele frequencies were found between morphs at the Cath2 and MHCIIα loci. No such signal was detected in the D-loop nor in the other two immunological genes. In Cath2 the small benthic morph deviated from the other two (FST  = 0.13, one of the substitutions detected constituting an amino acid replacement polymorphism in the antimicrobial peptide. A more striking difference was found in the MHCIIα. Two haplotypes were very common in the lake, and their frequency differed greatly between the morphotypes (from 22% to 93.5%, FST  = 0.67. We then expanded our study by surveying the variation in Cath2 and MHCIIα in 9 Arctic charr populations from around Iceland. The populations varied greatly in terms of allele frequencies at Cath2, but the variation did not correlate with morphotype. At the MHCIIα locus, the variation was nearly identical to the variation in the two benthic morphs of Lake Thingvallavatn. The results are consistent with a scenario where parts of the immune systems have diverged substantially among Arctic charr populations in Iceland, after colonizing the island ∼10.000 years ago.

  8. Ontogeny, variation, and homology in Salvelinus alpinus caudal skeleton (Teleostei: Salmonidae).

    Science.gov (United States)

    Grünbaum, Thomas; Cloutier, Richard

    2010-01-01

    The ontogeny of the caudal skeleton in the Arctic charr, Salvelinus alpinus was examined using an extensive series of cleared and stained specimens. We demonstrate the presence of skeletal components never reported previously within the Salmonidae. In contrast to the generalized condition for salmonids, seven hypurals (instead of six), and four uroneurals (instead of three) have been found in some specimens. Variation in the number and condition of epurals is documented. New hypotheses are proposed concerning (1) relationships among centra and their associated elements, (2) phylogenetic distribution of caudal characters within the Salmonidae, and (3) homology of caudal components. Using the published phylogenetic hypotheses, we provide evidence, that a seventh hypural and a fourth uroneural are taxic atavism in salmonids. The development of the salmonid homocercal fin is discussed in the light of a polyural scheme based on evidences of a one-to-one relationship among ural centra and their associated elements. PMID:19603412

  9. Do stocked hatchery-reared juveniles ecologically suppress wild juveniles in Salvelinus leucomaenis?

    Science.gov (United States)

    Nakamura, T; Doi, T

    2014-05-01

    The dominancy of semi-wild and hatchery-reared white-spotted charr Salvelinus leucomaenis juveniles was evaluated using pair-wise enclosure tests and field stocking tests. The semi-wild S. leucomaenis originated in a hatchery, being stocked into the test stream as eyed-eggs. In the pair-wise enclosure test, the semi-wild S. leucomaenis dominated the hatchery S. leucomaenis that were of a similar standard length (L(S) ). The semi-wild S. leucomaenis were subordinate to hatchery S. leucomaenis that were > 11% larger in LS . In the field stocking test, the abundance and growth of semi-wild S. leucomaenis was decreased in the presence of larger hatchery S. leucomaenis (14% larger LS ). Taken together, these results suggest that larger hatchery S. leucomaenis ecologically suppress the smaller semi-wild S. leucomaenis. Salvelinus leucomaenis juveniles that are stocked with the intention of supplementing natural populations should be < 10% larger than their wild counterparts at the time of stocking to minimize their competitive advantage. The semi-wild and hatchery S. leucomaenis used in both tests were genetically similar individuals, suggesting that the differences are due to the early rearing environment of either a natural stream or hatchery. The hatchery S. leucomaenis have lower levels of aggression as a result of selection in the hatchery rearing environment. Rearing in a natural stream from the eyed-egg stage is likely to increase their lowered aggression.

  10. Distribution of Po-210 and Pb-210 in Arctic Char (Salvelinus alpinus) from an Arctic freshwater lake

    International Nuclear Information System (INIS)

    There is little information available with regard to the accumulation of Po-210 and Pb-210 by freshwater fish in natural freshwater systems despite the potential for relevant ingestion doses to man. This is maybe of particular pertinence for certain population groups where freshwater fish are an important dietary food item. Equally, it is important to understand the body distributions of these naturally occurring radionuclides to quantify the resulting doses to different tissues and organs of freshwater fish. With regard to the latter, it is important to consider not only the doses arising from bio-accumulated Po-210 and Pb-210 in various body compartments but additionally the internal dose from unabsorbed Po-210 and Pb-210 in the digestive tract. In this study, activity concentrations of Po-210 and Pb-210 were determined in muscle and various internal organs of Arctic Charr (Salvelinus alpinus) sampled from a lake in the Norwegian Arctic (69 deg. 4' N, 19 deg. 20' E). Observed activity concentrations of Po-210 and Pb-210 in different tissues will be discussed in relation to physiological parameters and ambient lake water activity concentrations. Results from this study will be compared to two similar studies conducted in freshwater systems where elevated activity concentrations of these radionuclides have been observed. Ingestion dose rates to man and effective absorbed dose rates to different tissues and organs of Arctic Charr from Po-210 and Pb-210 will be derived and compared to those from observed activity concentrations of the anthropogenic radionuclide Cs-137. (authors)

  11. Environmental contaminants in brook trout (Salvelinus fontinalis) from Cove Brook and two tributaries of the Sheepscot River

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Atlantic salmon (Salmo salar) is a federally-listed endangered species with a Distinct Population Segment (DPS) designated in Maine. In July 2006, thirty-six...

  12. Distribution of Po-210 and Pb-210 in Arctic Char (Salvelinus alpinus) from an Arctic freshwater lake

    Energy Technology Data Exchange (ETDEWEB)

    Gwynn, J.P.; Rudolfsen, G. [Norwegian Radiation Protection Authority, The Fram Centre, Tromsoe (Norway)

    2014-07-01

    There is little information available with regard to the accumulation of Po-210 and Pb-210 by freshwater fish in natural freshwater systems despite the potential for relevant ingestion doses to man. This is maybe of particular pertinence for certain population groups where freshwater fish are an important dietary food item. Equally, it is important to understand the body distributions of these naturally occurring radionuclides to quantify the resulting doses to different tissues and organs of freshwater fish. With regard to the latter, it is important to consider not only the doses arising from bio-accumulated Po-210 and Pb-210 in various body compartments but additionally the internal dose from unabsorbed Po-210 and Pb-210 in the digestive tract. In this study, activity concentrations of Po-210 and Pb-210 were determined in muscle and various internal organs of Arctic Charr (Salvelinus alpinus) sampled from a lake in the Norwegian Arctic (69 deg. 4' N, 19 deg. 20' E). Observed activity concentrations of Po-210 and Pb-210 in different tissues will be discussed in relation to physiological parameters and ambient lake water activity concentrations. Results from this study will be compared to two similar studies conducted in freshwater systems where elevated activity concentrations of these radionuclides have been observed. Ingestion dose rates to man and effective absorbed dose rates to different tissues and organs of Arctic Charr from Po-210 and Pb-210 will be derived and compared to those from observed activity concentrations of the anthropogenic radionuclide Cs-137. (authors)

  13. Genetic Diversity and Hybridisation between Native and Introduced Salmonidae Fishes in a Swedish Alpine Lake.

    Directory of Open Access Journals (Sweden)

    Leanne Faulks

    Full Text Available Understanding the processes underlying diversification can aid in formulating appropriate conservation management plans that help maintain the evolutionary potential of taxa, particularly under human-induced activities and climate change. Here we assessed the microsatellite genetic diversity and structure of three salmonid species, two native (Arctic charr, Salvelinus alpinus and brown trout, Salmo trutta and one introduced (brook charr, Salvelinus fontinalis, from an alpine lake in sub-arctic Sweden, Lake Ånn. The genetic diversity of the three species was similar and sufficiently high from a conservation genetics perspective: corrected total heterozygosity, H'T = 0.54, 0.66, 0.60 and allelic richness, AR = 4.93, 5.53 and 5.26 for Arctic charr, brown trout and brook charr, respectively. There were indications of elevated inbreeding coefficients in brown trout (GIS = 0.144 and brook charr (GIS = 0.129 although sibling relationships were likely a confounding factor, as a high proportion of siblings were observed in all species within and among sampling locations. Overall genetic structure differed between species, Fst = 0.01, 0.02 and 0.04 in Arctic charr, brown trout and brook charr respectively, and there was differentiation at only a few specific locations. There was clear evidence of hybridisation between the native Arctic charr and the introduced brook charr, with 6% of individuals being hybrids, all of which were sampled in tributary streams. The ecological and evolutionary consequences of the observed hybridisation are priorities for further research and the conservation of the evolutionary potential of native salmonid species.

  14. Genetic Diversity and Hybridisation between Native and Introduced Salmonidae Fishes in a Swedish Alpine Lake

    Science.gov (United States)

    Faulks, Leanne; Östman, Örjan

    2016-01-01

    Understanding the processes underlying diversification can aid in formulating appropriate conservation management plans that help maintain the evolutionary potential of taxa, particularly under human-induced activities and climate change. Here we assessed the microsatellite genetic diversity and structure of three salmonid species, two native (Arctic charr, Salvelinus alpinus and brown trout, Salmo trutta) and one introduced (brook charr, Salvelinus fontinalis), from an alpine lake in sub-arctic Sweden, Lake Ånn. The genetic diversity of the three species was similar and sufficiently high from a conservation genetics perspective: corrected total heterozygosity, H’T = 0.54, 0.66, 0.60 and allelic richness, AR = 4.93, 5.53 and 5.26 for Arctic charr, brown trout and brook charr, respectively. There were indications of elevated inbreeding coefficients in brown trout (GIS = 0.144) and brook charr (GIS = 0.129) although sibling relationships were likely a confounding factor, as a high proportion of siblings were observed in all species within and among sampling locations. Overall genetic structure differed between species, Fst = 0.01, 0.02 and 0.04 in Arctic charr, brown trout and brook charr respectively, and there was differentiation at only a few specific locations. There was clear evidence of hybridisation between the native Arctic charr and the introduced brook charr, with 6% of individuals being hybrids, all of which were sampled in tributary streams. The ecological and evolutionary consequences of the observed hybridisation are priorities for further research and the conservation of the evolutionary potential of native salmonid species. PMID:27032100

  15. Ecology and impacts of nonnative salmonids with special reference to brook trout (Salvelinus fontinalis Mitchill) in North Europe

    OpenAIRE

    Korsu, K. (Kai)

    2008-01-01

    Abstract My main objectives in this thesis were to explore general patterns and mechanisms driving salmonid invasions globally and, more specifically, to examine the invasion dynamics and impacts of the North American brook trout in North European stream systems. Non-native salmonids have often spread extensively and caused many harmful impacts on their native counterparts. Among the three globally introduced salmonids, the European brown trout appeared as the 'worst' alien species (st...

  16. Esterification and hydrolysis of vitamin A in the liver of brook trout (Salvelinus fontinalis) and the influence of a coplanar polychlorinated biphenyl

    Energy Technology Data Exchange (ETDEWEB)

    Ndayibagira, A.; Spear, P.A. [Centre de Recherche TOXEN and Departement des Sciences Biologiques, Universite du Quebec a Montreal, C.P. 8888, succursale Centre Ville Montreal (Canada)

    1999-03-01

    Recent reports of extremely low retinoid stores in fish living in contaminated river systems prompted an initial investigation of the mechanisms of hepatic storage and mobilization in brook trout. Enzyme characterization in microsomes revealed a lecithin:retinol acyltransferase activity (LRAT) optimum in the alkaline range (pH 9.0; V{sub max}=0.6 nmol per mg prot. h{sup -1}; K{sub m}=10.2 {mu}M) which is not known to occur in mammals, in addition to a secondary optimum at pH 6.5 typical of mammals. Acyl CoA:retinol acyltransferase (ARAT) kinetic parameters were quite different to those of mammals. The substrate affinity of trout ARAT (K{sub m}=1.6 {mu}M) was approximately 22-fold greater than that of the rat while maximal velocity (V{sub max}=0.2 nmol per mg prot. h{sup -1}) was 18-fold less. Retinyl ester hydrolase activity (REH) was optimal under acid conditions (pH 4.2; V{sub max}=6.6 nmol per mg prot. h{sup -1}; K{sub m}=0.6 mM), was inhibited by a bile salt analogue and was greater in males than females. This REH was tentatively categorized as a bile salt-independent, acid retinyl ester hydrolase (BSI-AREH). REH was inhibited in a dose-dependent manner following in vivo exposure to a representative environmental contaminant the coplanar polychlorinated biphenyl (PCB), 3,3minutes or feet,4,4minutes or feet-tetrachlorobiphenyl (TCBP). Inhibition may be an indirect effect because enzyme activity was not affected by in vitro exposure of control microsomes. REH inhibition in the brook trout may affect the uptake of retinyl esters (REs) from chylomicron remnants as well as the mobilization of stored REs. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  17. KAYNAK ALABALIĞI (SALVELINUS FONTINALIS)’NIN SPERMATOLOJİK ÖZELLİKLERİ VE SPERMANIN KISA SÜRELİ MUHAFAZASI

    OpenAIRE

    Şahin, Temel; Köse, Özay

    2015-01-01

    This study was carried out to determine the spermatologic characteristics and to develop an extender for the short-term storage of semen from brook trout. Four different extenders were tested in the study: a) 8.75 g/l NaCl, 0.20 g/l KCl, 0.20 CaCl2, 0.30 g/l NaHCO3 (S1), b) 8.75 g/l NaCl, 0.20 g/l KCl, 0.20 MgCl2, 0.40 g/l NaHCO3 (S2), c) 7.25 g/l NaCl, 0.40 g/l KCl, 0.80 g/l NaHCO3, 2.0 g/l glucose (S3), d) 8.75 g/l NaCl, 0.20 g/l KCl, 0.10 CaCl2, 0.10 g/l MgCl2, 0.40 g/l NaHCO3 (S4). In the...

  18. 患病北极红点鲑的病原分离与鉴定%Isolation and Identification of Causative Agents of Sick Arctic Charr (Salvelinus alpinus)

    Institute of Scientific and Technical Information of China (English)

    史秀杰; 刘荭; 高隆英; 何俊强; 江育林

    2007-01-01

    对2004年5月四川省某养殖基地养殖的北极红点鲑患病鲑进行了病理学检查和病原分离,从病灶处分离到细菌和真菌.分离到的细菌经API生化鉴定为杀鲑气单胞菌杀鲑亚种(Aeromonas salmonicida subsp.salmonicida).用引物AP1和AP2对纯化后的细菌进行PCR扩增,结果扩增出长度为421 bp的DNA片段,对扩增片段进行克隆、测序,用NCBI-BLASTn在GenBank中搜寻相似序列,结果与杀鲑气单胞菌各株A层蛋白部分编码基因有99%以上的序列同源性.用引物EUS-F和EUS-R对分离到的真菌进行PCR扩增,结果扩增出长度为755 bp的DNA片段,对扩增片段进行克隆、测序,用NCBI-BLASTn在GenBank中搜寻相似序列,结果与水霉属各株的DNA片段(包括18S核糖体RNA基因部分序列、内转录间隔区1全序列、5.8S核糖体RNA基因全序列、内转录间隔区2全序列和28S核糖体RNA部分序列)有93%~100%的同源性;而与属于丝囊霉菌属的EUS各株相对应的DNA片段仅有60%的序列同源性.因此判定所分离的真菌为水霉.杀鲑气单胞菌是引起疖疮病和溃疡病等病的病原菌,而水霉广泛存在于水中,当鱼受伤后,水霉孢子容易从患病部位侵入鱼体,加重感染.因此判断该病主要是由杀鲑气单胞菌引起,而水霉则引起继发感染.

  19. Fine-scale oscillatory banding in otoliths from arctic charr (Salveninus alpinus) and pike (Esox lucius)

    Energy Technology Data Exchange (ETDEWEB)

    Meldrum, A. [Oak Ridge National Lab., TN (United States); Halden, N.M. [Univ. of Manitoba, Winnipeg (Canada). Dept. of Geological Sciences

    1997-12-31

    Transmission electron microscopy of otoliths from the inner ear of arctic charr and pike has revealed the presence of fine banding on the scale of several nanometers. The thickness of the bands was observed to vary in different portions of the sample, and some areas were not banded. EDS analysis could not detect chemical differences within the bands, but electron diffraction showed that the crystallographic orientation of the bands is related by a lattice mismatch. Previously, banding on the scale of 50 to 100 microns was observed by SEM in otoliths from arctic charr and was attributed to seasonal variations in growth. The fine-scale banding observed in this study, however, is unlikely to represent a daily variation. Electron diffraction from the pike samples shows that the material is composed of CaCO{sub 3} having the both the vaterite and aragonite structure, and hydrous CaCO{sub 3} was also observed. The large-scale banding previously identified by SEM was not observed in the TEM despite attempts to intersect the boundaries of the micron-sized layers. The interaction of the electron beam with the sample material was investigated by conducting several electron-irradiation experiments. The electron beam was observed to interact strongly with the sample and caused the precipitation of cubic CaO from the calcium carbonate matrix. Bright-field imaging showed the development of fine grained ({approximately} 5 nm) randomly oriented crystallites which accumulated with increasing electron dose. These initial results suggest that the precipitation of CaO is not driven by electron-beam beating. Previously, a similar phase-change phenomenon has been observed in hydroxyapatite from dental enamel. Other Ca-bearing biominerals may therefore also be expected to be sensitive to electron irradiation.

  20. Expression of miR-199a, lum and ets2 in benthic and pelagic Arctic charr morphs at developmental stage 200τ

    OpenAIRE

    Ligthart, Kate, 1992-

    2014-01-01

    MiRNAs play an important role in development by regulating gene expression. They are recruited to RISC complexes, which bind to target mRNAs. This interaction causes silencing of the target mRNAs by repressing translation or by initiating degradation. In lake Þingvallavatn there are four morphs of Arctic charr that are very different in morphology and their feeding apparatus. The different morphs of Arctic charr have different levels of miRNA gene expression during their embryonic development...

  1. The use of aquatic moss (Fontinalis antipyretica as monitor of contamination in standing and running waters: limits and advantages

    Directory of Open Access Journals (Sweden)

    Roberto M. CENCI

    2001-09-01

    Full Text Available The aim of this work is to verify whether water moss (Fontinalis antipyretica could be used as a monitor of trace element contamination in lotic and lentic waters. The investigation was split up the into three sequential experimental trials. 1 Experiments have been set up in lab in order to evaluate the amount of trace elements (Cd, Pb, Cr, Cu and Hg released by moss during a period of 133 days, under controlled chemical-physical conditions. A release of 64% of Hg, 83% of Cr and 70% of Pb was found, whereas no re lease of Cd and Cu has been observed. 2 Clean moss has successively treated with running water at different pH and then treaded with Cu, Cr, Hg and Pb, in order to evaluate the dynamics of accumulation of trace elements in moss. Specifically, three basins containing 100 liters of Lake Maggiore water were equipped with three distinct pumps (15 l min-1 each ensuring the water circulation into a glass tube were arranged. Afterwards, 105 thallus, equivalent to 4.5 g of Fontinalis antipyretica, were fixed into each glass tube. The accumulation dynamics was calculated by collecting moss and water at the beginning, after 1 h, 6 h, 1 day, 4, 9, 14 and 28 days of the experiment. Results showed that the metals accumulation was significant during the first hour. 3 Samples of clean moss were placed in situ. Nine sites in Lake Orta, characterized by high contents of elements due to the anthropic activities, the Toce River and other minor rivers, have been chosen in order to estimate the ability of moss to accumulate Cu, Cr, Pb and Hg from water, and to localize the metal pollution sources. In three sites the Cu average concentration in Fontinalis antipyretica increased from 167 mg kg-1 dry moss to 2100 mg kg-1 after 14 days and to 2900 mg kg-1 after 28 days. A marked accumulation of Hg was observed in Fontinalis antipyretica located in site no 6 (from an initial concentration of 0.2 mg kg-1 dry moss to 17.7 mg kg-1 after 14 days, and 24.6 mg kg-1

  2. Sprint swimming performance of wild bull trout (Salvelinus confluentus)

    Science.gov (United States)

    Mesa, M.G.; Phelps, J.; Weiland, L.K.

    2008-01-01

    We conducted laboratory experiments to determine the sprint swimming performance of wild juvenile and adult bull trout Salvelinus confluentus. Sprint swimming speeds were estimated using high-speed digital video analysis. Thirty two bull trout were tested in sizes ranging from about 10 to 31 cm. Of these, 14 fish showed at least one motivated, vigorous sprint. When plotted as a function of time, velocity of fish increased rapidly with the relation linear or slightly curvilinear. Their maximum velocity, or Vmax, ranged from 1.3 to 2.3 m/s, was usually achieved within 0.8 to 1.0 s, and was independent of fish size. Distances covered during these sprints ranged from 1.4 to 2.4 m. Our estimates of the sprint swimming performance are the first reported for this species and may be useful for producing or modifying fish passage structures that allow safe and effective passage of fish without overly exhausting them. ?? 2008 by the Northwest Scientific Association. All rights reserved.

  3. Multiscale hydrogeomorphic influences on bull trout (Salvelinus confluentus) spawning habitat

    Science.gov (United States)

    Bean, Jared R; Wilcox, Andrew C.; Woessner, William W; Muhlfeld, Clint C.

    2015-01-01

    We investigated multiscale hydrogeomorphic influences on the distribution and abundance of bull trout (Salvelinus confluentus) spawning in snowmelt-dominated streams of the upper Flathead River basin, northwestern Montana. Within our study reaches, bull trout tended to spawn in the finest available gravel substrates. Analysis of the mobility of these substrates, based on one-dimensional hydraulic modeling and calculation of dimensionless shear stresses, indicated that bed materials in spawning reaches would be mobilized at moderate (i.e., 2-year recurrence interval) high-flow conditions, although the asynchronous timing of the fall–winter egg incubation period and typical late spring – early summer snowmelt high flows in our study area may limit susceptibility to redd scour under current hydrologic regimes. Redd occurrence also tended to be associated with concave-up bedforms (pool tailouts) with downwelling intragravel flows. Streambed temperatures tracked stream water diurnal temperature cycles to a depth of at least 25 cm, averaging 6.1–8.1 °C in different study reaches during the spawning period. Ground water provided thermal moderation of stream water for several high-density spawning reaches. Bull trout redds were more frequent in unconfined alluvial valley reaches (8.5 versus 5.0 redds·km−1 in confined valley reaches), which were strongly influenced by hyporheic and groundwater – stream water exchange. A considerable proportion of redds were patchily distributed in confined valley reaches, however, emphasizing the influence of local physical conditions in supporting bull trout spawning habitat. Moreover, narrowing or “bounding” of these alluvial valley segments did not appear to be important. Our results suggest that geomorphic, thermal, and hydrological factors influence bull trout spawning occurrence at multiple spatial scales.

  4. Fish and crustaceans in northeast Greenland lakes with special emphasis on interactions between Arctic charr (Salvelinus alpinus), Lepidurus arcticus and benthic chydorids

    DEFF Research Database (Denmark)

    Jeppesen, E.; Christoffersen, K.; Landkildehus, F.;

    2001-01-01

    in the sediment of these lakes. No significant differences between lakes with and without fish were found in chlorophyll a, total phosphorus, total nitrogen, conductivity or temperature, suggesting that the observed link between Lepidurus arcticus and the benthic crustacean community is causal. Consequently...

  5. Techniques for Functional Testing of Factors Associated with Arctic charr Polymorphism: phenotypic analysis in zebrafish and in vitro assays in cell culture

    OpenAIRE

    O'Sullivan, Freya Mae, 1996-

    2016-01-01

    Trophic morphology in Teleosts, including the jaw and pharyngeal arches, determines feeding type and performance. Polymorphism in trophic morphology facilitates niche partitioning and the coexistence of morphs within ecosystems. In Lake Thingvallavatn, Iceland, Arctic charr displays four morphs, two benthic; small (SB) and large (LB), and two pelagic; piscivorous (PI) and planktivorous (PL). These ecomorphs show disparity in behaviour, morphology and feeding type, as well as variation in gene...

  6. Chronic toxicity of tributyltin on development and reproduction of the hermaphroditic snail Physa fontinalis: Influence of population density.

    Science.gov (United States)

    Leung, Kenneth M Y; Morley, Neil J; Grist, Eric P M; Morritt, David; Crane, Mark

    2004-01-01

    Tributyltin (TBT) is toxic to aquatic organisms and occurs widely in sediments and surface waters of American and European rivers and lakes. This study investigated TBT effects on development and population growth rate (r) of the common, hermaphroditic European freshwater snail Physa fontinalis. Egg ropes of similar age (1-3 days old) were exposed to a control (solvent only) and nominal concentrations of 0.01, 1.0 and 10 microg TBT l(-1) in triplicate. Hatching and mortality were recorded during 0-40 days of exposure. At day 40, 18 juveniles were randomly selected from each concentration (i.e., six from each test vessel) and individually exposed to the same concentration of TBT in 50 ml beakers. A cohort of 20 juveniles was allowed to continue developing in the original test vessels, so that individual and grouped results could be compared. Mortality and reproduction were recorded at 48-h intervals throughout the study period (110 days). Abnormal embryonic development was observed at 1 and 10 microg TBT l(-1). Although 50% of eggs hatched at 10 microg TBT l(-1), all these hatchlings failed to survive. Survivorship of hatchlings was significantly reduced by TBT at 1 microgl(-1). In general, there was a delay in egg production in isolated snails when compared with the grouped snails. Survival, fecundity and population growth rate (r) were reduced in both individual and grouped P. fontinalis at 1.0 microg TBT l(-1). Only a decline in r was observed in snails exposed individually to 0.01 microg TBT l(-1).

  7. Effects of roads on bull trout (Salvelinus confluentus), a federally threatened species

    OpenAIRE

    Teachout, Emily; Quan, Jennifer

    2001-01-01

    The bull trout (Salvelinus confluentus) is federally listed as threatened under the Endangered Species Act. Bull trout are apex predators requiring a large prey base and a large home range, and are known to move throughout and between basins in search of prey. However, bull trout are dependent upon very cold, clean waters for spawning (below 9 degrees Celsius) and are typically characterized as spawning in the upper-most reaches of watersheds. Bull trout have four life history forms: resident...

  8. Trace elements in the Fontinalis antipyretica from rivers receiving sewage of lignite and glass sand mining industry.

    Science.gov (United States)

    Kosior, Grzegorz; Samecka-Cymerman, Aleksandra; Kolon, Krzysztof; Brudzińska-Kosior, Anna; Bena, Waldemar; Kempers, Alexander J

    2015-07-01

    Intensive lignite and glass sand mining and industrial processing release waste which may contain elements hazardous to the aquatic ecosystem and constitute a potential risk to human health. Therefore, their levels must be carefully controlled. As a result, we examined the effects of sewage on the aquatic Fontinalis antipyretica moss in the Nysa Łużycka (lignite industry) and the Kwisa Rivers (glass sand industry). The Nysa Łużycka and the Kwisa Rivers appeared to be heavily polluted with As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn, which were reflected in the extremely high concentration of these elements in F. antipyretica along the studied watercourses. In the Nysa Łużycka, trace element composition in the moss species is affected by lignite industry with accumulation in its tissues of the highest concentrations of Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn, while samples from the Kwisa sites influenced by glass sand industry revealed the highest concentrations of As, V and Fe. The principal component and classification analysis classifies the concentration of elements in the aquatic F. antipyretica moss, thus enabling the differentiation of sources of water pollution in areas affected by mining industry. PMID:25647494

  9. Substrate selection and seasonal variation in abundance and size composition of isopod Lirceus fontinalis in Ontario streams, Canada

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xiaoxia; Michael G. FOX; David C. LASENBY; Alexis C. ARMIT; Dolly N. KOTHAWALA

    2007-01-01

    The abundance and size composition of stream isopods Lirceus fontinalis were investigated from April 2001 to August 2002 in 3 streams in southern Ontario, Canada. Effects of current speed was released from the analysis by choosing slow flowing water. The effects of substrate, season and water depth on the abundance, distribution and size composition of the isopods were analyzed. It was found that substrate and season influence isopods the most. The rocky substrate with attached filamentous macro-algae contains an isopod abundance 7.05 times that of bare rock substrate and 14.6 times that of fine-sand and mud substrate. There was a large variation with respect to seasonality in both abundance and size composition of the isopods, with the highest abundance occurring in summer and the lowest in winter and spring; individual isopods also tend to be larger in the winter and spring. In all substrates,shallow areas tend to support higher densities of isopods than deeper areas.

  10. Effects of the introduction of Lake Trout (Salvelinus Namaycush) on the Osprey (Pandion Haliaetus) population in Yellowstone National Park

    OpenAIRE

    Søyland, Anders

    2011-01-01

    In recent years the number and reproduction of ospreys (Pandion haliaetus) nesting on Yellowstone Lake in Yellowstone National Park (YNP), USA, has been declining. The main hypothesis is that the decline in nesting ospreys is due to the introduction of the lake trout (Salvelinus namaycush), which is believed to have reduced the cutthroat trout (Oncorhynchus clarki bouvieri) population in Yellowstone Lake substantially. The lake trout inhabit deeper water range than the cutthroat and is theref...

  11. Spawning site fidelity of wild and hatchery lake trout (Salvelinus namaycush) in northern Lake Huron

    Science.gov (United States)

    Binder, Thomas; Riley, Stephen C.; Holbrook, Christopher; Hansen, Michael J.; Bergstedt, Roger A.; Bronte, Charles R.; He, Ji; Krueger, Charles C.

    2016-01-01

    Fidelity to high-quality spawning sites helps ensure that adults repeatedly spawn at sites that maximize reproductive success. Fidelity is also an important behavioural characteristic to consider when hatchery-reared individuals are stocked for species restoration, because artificial rearing environments may interfere with cues that guide appropriate spawning site selection. Acoustic telemetry was used in conjunction with Cormack–Jolly–Seber capture–recapture models to compare degree of spawning site fidelity of wild and hatchery-reared lake trout (Salvelinus namaycush) in northern Lake Huron. Annual survival was estimated to be between 77% and 81% and did not differ among wild and hatchery males and females. Site fidelity estimates were high in both wild and hatchery-reared lake trout (ranging from 0.78 to 0.94, depending on group and time filter), but were slightly lower in hatchery-reared fish than in wild fish. The ecological implication of the small difference in site fidelity between wild and hatchery-reared lake trout is unclear, but similarities in estimates suggest that many hatchery-reared fish use similar spawning sites to wild fish and that most return to those sites annually for spawning.

  12. Allantoinase in lake trout (Salvelinus namaycush): in vitro effects of PCBs, DDT and metals

    Science.gov (United States)

    Passino, Dora R. May; Cotant, Carol A.

    1979-01-01

    1. Allantoinase, an enzyme in the purine-urea cycle, was found in livers of Salvelinus namaycush (Osteichthyes: Salmoniformes). 2. The enzyme was active from pH 6.6 to 8.2 at 37°C and from pH 7.4 to 9.0 at 10°C and had an Arrhenius energy of activation of 11.0 kcal/mol and a temperature quotient of 2.0. The Km of the enzyme homogenate was 8.4 mM allantoin. 3. The concentration of inorganic metals at which 50% inhibition occurred during in vitro exposure were 6.0 mg/l Cu2+, 6.7 mg/l Cd2+, 34 mg/l Hg2+ and 52 mg/l Pb2+. The in vitro sensitivity to PCBs, DDT and DDE and kinetics in the presence of metals were determined. 4. Allantoinase activity was negatively correlated with body length for fish from Lake Michigan but not from Lake Superior or the laboratory.

  13. Dwarf char, a new form of chars (the genus Salvelinus) in Lake Kronotskoe

    Science.gov (United States)

    Pavlov, S.D.; Pivovarov, E.A.; Ostberg, C.O.

    2012-01-01

    Lake Kronotskoe is situated in the Kronotskii State Nature Reserve and is a unique natural heritage of Kamchatka. The lake–river system of the reserve includes numerous springs and small streams and three large inflowing rivers, Listvennichnaya, Unana, and Uzon, which form the main bays of Lake Kronotskoe; one river (Kronotskaya) flows from the lake. This river is characterized by several rapids, which are assumed to be unsurmountable barriers for fish migration. The ichthyofauna of the lake has been isolated for a long time, and some endemic fishes appeared, including char of the genus Salvelinus and the residential form of red salmon Oncorhynchus nerka (the local name is kokanee). These species are perfect model objects to study microevolution processes. Char of Lake Kronotskoe are characterized by significant polymorphism and plasticity [1–3]; therefore, they are extremely valuable for studying the processes of speciation and form development. That is why the populations of char in Lake Kronotskoe are unique and attract special attention of researchers. 

  14. Lake trout (Salvelinus namaycush) populations in Lake Superior and their restoration in 1959-1993

    Science.gov (United States)

    Hansen, Michael J.; Peck, James W.; Schorfhaar, Richard G.; Selgeby, James H.; Schreiner, Donald R.; Schram, Stephen T.; Swanson, Bruce L.; MacCallum, Wayne R.; Burnham-Curtis, Mary K.; Curtis, Gary L.; Heinrich, John W.; Young, Robert J.

    1995-01-01

    Naturally-reproducing populations of lake trout (Salvelinus namaycush) have been reestablished in most of Lake Superior, but have not been restored to 1929-1943 average abundance. Progress toward lake trout restoration in Lake Superior is described, management actions are reviewed, and the effectiveness of those actions is evaluated; especially stocking lake trout as a tool for building spawning stocks, and subsequently, populations of wild recruits. Widespread destruction of lake trout stocks in the 1950s due to an intense fishery and sea lamprey (Petromyzon marinus) predation resulted in lower overall phenotypic diversity than was previously present. Stocking of yearling lake trout, begun in the 1950s, produced high densities of spawners that reproduced wherever inshore spawning habitat was widespread. Sea lampreys were greatly reduced, beginning in 1961, using selective chemical toxicants and barrier dams, but continue to exert substantial mortality. Fishery regulation was least effective in Wisconsin, where excessive gillnet effort caused high by-catch of lake trout until 1991, and in eastern Michigan, where lake trout restoration was deferred in favor of a tribal fishery for lake whitefish (Coregonus clupeaformis) in 1985. Restoration of stocks was quicker in offshore areas where remnant wild lake trout survived and fishing intensity was low, and was slower in inshore areas where stocked lake trout reproduced successfully and fishing intensity was high. Inshore stocks of wild lake trout are currently about 61 % of historic abundance in Michigan and 53% in Wisconsin. Direct comparison of modern and historic abundances of inshore lake trout stocks in Minnesota and Ontario is impossible due to lack of historic stock assessment data. Stocks in Minnesota are less abundant at present than in Michigan or Wisconsin, and stocks in Ontario are similar to those in Michigan. Further progress in stock recovery can only be achieved if sea lampreys are depressed and if

  15. Genetic and phenotypic variation along an ecological gradient in lake trout Salvelinus namaycush

    Science.gov (United States)

    Baillie, Shauna M.; Muir, Andrew M.; Hansen, Michael J.; Krueger, Charles C.; Bentzen, Paul

    2016-01-01

    BackgroundAdaptive radiation involving a colonizing phenotype that rapidly evolves into at least one other ecological variant, or ecotype, has been observed in a variety of freshwater fishes in post-glacial environments. However, few studies consider how phenotypic traits vary with regard to neutral genetic partitioning along ecological gradients. Here, we present the first detailed investigation of lake trout Salvelinus namaycushthat considers variation as a cline rather than discriminatory among ecotypes. Genetic and phenotypic traits organized along common ecological gradients of water depth and geographic distance provide important insights into diversification processes in a lake with high levels of human disturbance from over-fishing.ResultsFour putative lake trout ecotypes could not be distinguished using population genetic methods, despite morphological differences. Neutral genetic partitioning in lake trout was stronger along a gradient of water depth, than by locality or ecotype. Contemporary genetic migration patterns were consistent with isolation-by-depth. Historical gene flow patterns indicated colonization from shallow to deep water. Comparison of phenotypic (Pst) and neutral genetic variation (Fst) revealed that morphological traits related to swimming performance (e.g., buoyancy, pelvic fin length) departed more strongly from neutral expectations along a depth gradient than craniofacial feeding traits. Elevated phenotypic variance with increasing water depth in pelvic fin length indicated possible ongoing character release and diversification. Finally, differences in early growth rate and asymptotic fish length across depth strata may be associated with limiting factors attributable to cold deep-water environments.ConclusionWe provide evidence of reductions in gene flow and divergent natural selection associated with water depth in Lake Superior. Such information is relevant for documenting intraspecific biodiversity in the largest freshwater lake

  16. Temperature, pressure and light data collected by attached Archival Transmitting Tags to Salvelinus malma (Dolly Varden trout) in the Wulik River, Alaska, during 2012-06 to 2013-10 (NODC Accession 0119954)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains data collected by electronic tags (Pop-up Satellite Archival Transmitting) attached to Salvelinus malma (Dolly Varden trout) in the Wulik...

  17. Arctic char - friend or foe?: Climate driven seasonal variation in competitive impact of Arcticchar (Salvelinus alpinus L) on brown trout (Salmo truttaence L)

    OpenAIRE

    Ulvan, Eva Marita

    2010-01-01

    Here I test for climate driven seasonal effects on competition in lakes using brown trout (Salmo trutta L.) and Arctic char (Salvelinus alpinus L.) as model organisms. Winter and summer brown trout consumption rates were estimated by 1374 Cs tracer methodology using brown trout sampled in  allopatric (brown trout) and 10 sympatric (brown trout/Arctic char) lakes, located along an altitudinal gradient in central Scandinavia. Lake catchment area  vegetation properties ranged from southern borea...

  18. Seasonal Variations in Relative Weight of Lake Trout (Salvelinus namaycush), Kokanee Salmon (Oncorhynchus nerka), Rainbow Trout (Onocorhynchus mykiss), and Brown Trout (Salmo trutta) in Blue Mesa Reservoir, Colorado

    OpenAIRE

    Midas, Madeline; Williams, Asia; Cooper, Cindy; Courtney, Michael

    2013-01-01

    Blue Mesa Reservoir is the largest body of water in Colorado and is located on the western slope of the Rocky Mountains at an elevation of 7520 feet. Blue Mesa Reservoir contains recreationally important populations of lake trout (Salvelinus namaycush), kokanee salmon (Oncorhynchus nerka), rainbow trout (Onocorhynchus mykiss), and brown trout (Salmo trutta). A management challenge in recent years has been the overpopulation of lake trout, which has led to a steep decline in abundance of kokan...

  19. Environmental contaminants in brook trout from Aroostook National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — In June 2012, four brook trout (Salvelinus fontinalis) were collected by angling from Chapman Pond and East Loring Lake at Aroostook NWR in northeast Maine. Two...

  20. Great Smoky Mountains National Park Fish Distribution

    Data.gov (United States)

    National Park Service, Department of the Interior — Background and History The brook trout (Salvelinus fontinalis) is the only trout native to the southern Appalachian Mountains. It was once widespread in Great Smoky...

  1. Integrating Traditional and Evolutionary Knowledge in Biodiversity Conservation: a Population Level Case Study

    Directory of Open Access Journals (Sweden)

    Rene Dion

    2006-12-01

    Full Text Available Despite their dual importance in the assessment of endangered/threatened species, there have been few attempts to integrate traditional ecological knowledge (TEK and evolutionary biology knowledge (EBK at the population level. We contrasted long-term aboriginal TEK with previously obtained EBK in the context of seasonal migratory habits and population biology of a salmonid fish, brook charr, (Salvelinus fontinalis inhabiting a large, remote postglacial lake. Compilation of TEK spanning four decades involved analytical workshops, semidirective interviews, and collaborative fieldwork with local aboriginal informants and fishing guides. We found that TEK complemented EBK of brook charr by providing concordant and additional information about (1 population viability; (2 breeding areas and migration patterns of divergent populations; and (3 the behavioral ecology of populations within feeding areas; all of which may ultimately affect the maintenance of population diversity. Aboriginal concerns related to human pressures on this species, not revealed by EBK, also help to focus future conservation initiatives for divergent populations and to encourage restoration of traditional fishing practices. However, relative to EBK, the relevance of TEK to salmonid biodiversity conservation was evident mainly at a smaller spatial scale, for example, that of individual rivers occupied by populations or certain lake sectors. Nevertheless, EBK was only collected over a 4-yr period, so TEK provided an essential long-term temporal window to evaluate population differences and persistence. We concluded that, despite different conceptual underpinnings, spatially and temporally varying TEK and EBK both contribute to the knowledge base required to achieve sustainability and effective biodiversity conservation planning for a given species. Such integration may be particularly relevant in many isolated regions, where intraspecific diversity can go unrecognized due to sparse

  2. New insight into the spawning behavior of lake trout, Salvelinus namaycush, from a recovering population in the Laurentian Great Lakes

    Science.gov (United States)

    Binder, Thomas R.; Thompson, Henry T.; Muir, Andrew M.; Riley, Stephen C.; Marsden, J. Ellen; Bronte, Charles R.; Krueger, Charles C.

    2014-01-01

    Spawning behavior of lake trout, Salvelinus namaycush, is poorly understood, relative to stream-dwelling salmonines. Underwater video records of spawning in a recovering population from the Drummond Island Refuge (Lake Huron) represent the first reported direct observations of lake trout spawning in the Laurentian Great Lakes. These observations provide new insight into lake trout spawning behavior and expand the current conceptual model. Lake trout spawning consisted of at least four distinct behaviors: hovering, traveling, sinking, and gamete release. Hovering is a new courtship behavior that has not been previously described. The apparent concentration of hovering near the margin of the spawning grounds suggests that courtship and mate selection might be isolated from the spawning act (i.e., traveling, sinking, and gamete release). Moreover, we interpret jockeying for position displayed by males during traveling as a unique form of male-male competition that likely evolved in concert with the switch from redd-building to itinerant spawning in lake trout. Unlike previous models, which suggested that intra-sexual competition and mate selection do not occur in lake trout, our model includes both and is therefore consistent with evolutionary theory, given that the sex ratio on spawning grounds is skewed heavily towards males. The model presented in this paper is intended as a working hypothesis, and further revision may become necessary as we gain a more complete understanding of lake trout spawning behavior.

  3. Paenibacillus thiaminolyticus is not the cause of thiamine deficiency impeding lake trout (Salvelinus namaycush) recruitment in the Great Lakes

    Science.gov (United States)

    Richter, Catherine A.; Evans, Allison N.; Wright-Osment, Maureen K.; Zajicek, James L.; Heppell, Scott A.; Riley, Stephen C.; Krueger, Charles C.; Tillitt, Donald E.

    2012-01-01

    Thiamine (vitamin B1) deficiency is a global concern affecting wildlife, livestock, and humans. In Great Lakes salmonines, thiamine deficiency causes embryo mortality and is an impediment to restoration of native lake trout (Salvelinus namaycush) stocks. Thiamine deficiency in fish may result from a diet of prey with high levels of thiaminase I. The discoveries that the bacterial species Paenibacillus thiaminolyticus produces thiaminase I, is found in viscera of thiaminase-containing prey fish, and causes mortality when fed to lake trout in the laboratory provided circumstantial evidence implicating P. thiaminolyticus. This study quantified the contribution of P. thiaminolyticus to the total thiaminase I activity in multiple trophic levels of Great Lakes food webs. Unexpectedly, no relationship between thiaminase activity and either the amount of P. thiaminolyticus thiaminase I protein or the abundance of P. thiaminolyticus cells was found. These results demonstrate that P. thiaminolyticus is not the primary source of thiaminase activity affecting Great Lakes salmonines and calls into question the long-standing assumption that P. thiaminolyticus is the source of thiaminase in other wild and domestic animals.

  4. Subcellular distribution of trace elements and liver histology of landlocked Arctic char (Salvelinus alpinus) sampled along a mercury contamination gradient.

    Science.gov (United States)

    Barst, Benjamin D; Rosabal, Maikel; Campbell, Peter G C; Muir, Derek G C; Wang, Xioawa; Köck, Günter; Drevnick, Paul E

    2016-05-01

    We sampled landlocked Arctic char (Salvelinus alpinus) from four lakes (Small, 9-Mile, North, Amituk) in the Canadian High Arctic that span a gradient of mercury contamination. Metals (Hg, Se, Tl, and Fe) were measured in char tissues to determine their relationships with health indices (relative condition factor and hepatosomatic index), stable nitrogen isotope ratios, and liver histology. A subcellular partitioning procedure was employed to determine how metals were distributed between potentially sensitive and detoxified compartments of Arctic char livers from a low- and high-mercury lake (Small Lake and Amituk Lake, respectively). Differences in health indices and metal concentrations among char populations were likely related to differences in feeding ecology. Concentrations of Hg, Se, and Tl were highest in the livers of Amituk char, whereas concentrations of Fe were highest in Small and 9-Mile char. At the subcellular level we found that although Amituk char had higher concentrations of Tl in whole liver than Small Lake char, they maintained a greater proportion of this metal in detoxified fractions, suggesting an attempt at detoxification. Mercury was found mainly in potentially sensitive fractions of both Small and Amituk Lake char, indicating that Arctic char are not effectively detoxifying this metal. Histological changes in char livers, mainly in the form of melano-macrophage aggregates and hepatic fibrosis, could be linked to the concentrations and subcellular distributions of essential or non-essential metals.

  5. Network analysis highlights complex interactions between pathogen, host and commensal microbiota.

    Directory of Open Access Journals (Sweden)

    Sébastien Boutin

    Full Text Available Interactions between bacteria and their host represent a full continuum from pathogenicity to mutualism. From an evolutionary perspective, host-bacteria relationships are no longer considered a two-component system but rather a complex network. In this study, we focused on the relationship between brook charr (Salvelinus fontinalis and bacterial communities developing on skin mucus. We hypothesized that stressful conditions such as those occurring in aquaculture production induce shifts in the bacterial community of healthy fish, thus allowing pathogens to cause infections. The results showed that fish skin mucus microbiota taxonomical structure is highly specific, its diversity being partly influenced by the surrounding water bacterial community. Two types of taxonomic co-variation patterns emerged across 121 contrasted communities' samples: one encompassing four genera well known for their probiotic properties, the other harboring five genera mostly associated with pathogen species. The homeostasis of fish bacterial community was extensively disturbed by induction of physiological stress in that both: 1 the abundance of probiotic-like bacteria decreased after stress exposure; and 2 pathogenic bacteria increased following stress exposure. This study provides further insights regarding the role of mutualistic bacteria as a primary host protection barrier.

  6. Evolution and origin of sympatric shallow-water morphotypes of Lake Trout, Salvelinus namaycush, in Canada's Great Bear Lake.

    Science.gov (United States)

    Harris, L N; Chavarie, L; Bajno, R; Howland, K L; Wiley, S H; Tonn, W M; Taylor, E B

    2015-01-01

    Range expansion in north-temperate fishes subsequent to the retreat of the Wisconsinan glaciers has resulted in the rapid colonization of previously unexploited, heterogeneous habitats and, in many situations, secondary contact among conspecific lineages that were once previously isolated. Such ecological opportunity coupled with reduced competition likely promoted morphological and genetic differentiation within and among post-glacial fish populations. Discrete morphological forms existing in sympatry, for example, have now been described in many species, yet few studies have directly assessed the association between morphological and genetic variation. Morphotypes of Lake Trout, Salvelinus namaycush, are found in several large-lake systems including Great Bear Lake (GBL), Northwest Territories, Canada, where several shallow-water forms are known. Here, we assess microsatellite and mitochondrial DNA variation among four morphotypes of Lake Trout from the five distinct arms of GBL, and also from locations outside of this system to evaluate several hypotheses concerning the evolution of morphological variation in this species. Our data indicate that morphotypes of Lake Trout from GBL are genetically differentiated from one another, yet the morphotypes are still genetically more similar to one another compared with populations from outside of this system. Furthermore, our data suggest that Lake Trout colonized GBL following dispersal from a single glacial refugium (the Mississippian) and support an intra-lake model of divergence. Overall, our study provides insights into the origins of morphological and genetic variation in post-glacial populations of fishes and provides benchmarks important for monitoring Lake Trout biodiversity in a region thought to be disproportionately susceptible to impacts from climate change. PMID:25204304

  7. Effects of coancestry on accuracy of individual assignments to population of origin: examples using Great Lakes lake trout (Salvelinus namaycush).

    Science.gov (United States)

    Guinand, Bruno; Scribner, Kim T; Page, Kevin S; Filcek, Kristi; Main, Laura; Burnham-Curtis, Mary K

    2006-05-01

    Methods for assigning individuals to population of origin are widely used in ecological genetics, resources management, and forensics. Characteristics of genetic data obtained from putative source populations that enhance accuracy of assignment are well established. How non-independence within and among unknown individuals to be classified [i.e., gene correlations within individual (inbreeding) and gene correlations among individuals within group (coancestry)] affect assignment accuracy is poorly understood. We used empirical data for six microsatellite loci and offspring from full-sib crosses of hatchery strains of lake trout (Salvelinus namaycush; Salmonidae) representing known levels of coancestry (mean theta = 0.006 and 0.06) within families to investigate how gene correlations can affect assignment. Additional simulations were conducted to further investigating the influence of allelic diversity (2, 6 or 10 alleles per locus) and inbreeding (F = 0.00, 0.05, and 0.15) on assignment accuracy for cases of low and high inter-population variance in allele frequency (mean F (st) = 0.01 and 0.1, respectively). Inbreeding had no effect on accuracy of assignments. In contrast, variance in assignment accuracy across replicated simulations, and for each empirical case study increased with increasing coancestry, reflecting non-independence of probabilities of correct assignment among members of kin groups. Empirical estimates of assignment error rates should be interpreted with caution if appreciable levels of coancestry are suspected. Additional emphasis should be placed on sampling designs (spatially and temporally) that define or minimize the potential for sampling related individuals. PMID:16850237

  8. Laboratory Estimation of Net Trophic Transfer Efficiencies of PCB Congeners to Lake Trout (Salvelinus namaycush) from Its Prey

    Science.gov (United States)

    Madenjian, Charles P.; Rediske, Richard R.; O'Keefe, James P.; David, Solomon R.

    2014-01-01

    A technique for laboratory estimation of net trophic transfer efficiency (γ) of polychlorinated biphenyl (PCB) congeners to piscivorous fish from their prey is described herein. During a 135-day laboratory experiment, we fed bloater (Coregonus hoyi) that had been caught in Lake Michigan to lake trout (Salvelinus namaycush) kept in eight laboratory tanks. Bloater is a natural prey for lake trout. In four of the tanks, a relatively high flow rate was used to ensure relatively high activity by the lake trout, whereas a low flow rate was used in the other four tanks, allowing for low lake trout activity. On a tank-by-tank basis, the amount of food eaten by the lake trout on each day of the experiment was recorded. Each lake trout was weighed at the start and end of the experiment. Four to nine lake trout from each of the eight tanks were sacrificed at the start of the experiment, and all 10 lake trout remaining in each of the tanks were euthanized at the end of the experiment. We determined concentrations of 75 PCB congeners in the lake trout at the start of the experiment, in the lake trout at the end of the experiment, and in bloaters fed to the lake trout during the experiment. Based on these measurements, γ was calculated for each of 75 PCB congeners in each of the eight tanks. Mean γ was calculated for each of the 75 PCB congeners for both active and inactive lake trout. Because the experiment was replicated in eight tanks, the standard error about mean γ could be estimated. Results from this type of experiment are useful in risk assessment models to predict future risk to humans and wildlife eating contaminated fish under various scenarios of environmental contamination. PMID:25226430

  9. Estimates of lake trout (Salvelinus namaycush) diet in Lake Ontario using two and three isotope mixing models

    Science.gov (United States)

    Colborne, Scott F.; Rush, Scott A.; Paterson, Gordon; Johnson, Timothy B.; Lantry, Brian F.; Fisk, Aaron T.

    2016-01-01

    Recent development of multi-dimensional stable isotope models for estimating both foraging patterns and niches have presented the analytical tools to further assess the food webs of freshwater populations. One approach to refine predictions from these analyses is to include a third isotope to the more common two-isotope carbon and nitrogen mixing models to increase the power to resolve different prey sources. We compared predictions made with two-isotope carbon and nitrogen mixing models and three-isotope models that also included sulphur (δ34S) for the diets of Lake Ontario lake trout (Salvelinus namaycush). We determined the isotopic compositions of lake trout and potential prey fishes sampled from Lake Ontario and then used quantitative estimates of resource use generated by two- and three-isotope Bayesian mixing models (SIAR) to infer feeding patterns of lake trout. Both two- and three-isotope models indicated that alewife (Alosa pseudoharengus) and round goby (Neogobius melanostomus) were the primary prey items, but the three-isotope models were more consistent with recent measures of prey fish abundances and lake trout diets. The lake trout sampled directly from the hatcheries had isotopic compositions derived from the hatchery food which were distinctively different from those derived from the natural prey sources. Those hatchery signals were retained for months after release, raising the possibility to distinguish hatchery-reared yearlings and similarly sized naturally reproduced lake trout based on isotopic compositions. Addition of a third-isotope resulted in mixing model results that confirmed round goby have become an important component of lake trout diet and may be overtaking alewife as a prey resource.

  10. Sampling large geographic areas for rare species using environmental DNA: a study of bull trout Salvelinus confluentus occupancy in western Montana.

    Science.gov (United States)

    McKelvey, K S; Young, M K; Knotek, W L; Carim, K J; Wilcox, T M; Padgett-Stewart, T M; Schwartz, M K

    2016-03-01

    This study tested the efficacy of environmental DNA (eDNA) sampling to delineate the distribution of bull trout Salvelinus confluentus in headwater streams in western Montana, U.S.A. Surveys proved fast, reliable and sensitive: 124 samples were collected across five basins by a single crew in c. 8 days. Results were largely consistent with past electrofishing, but, in a basin where S. confluentus were known to be scarce, eDNA samples indicated that S. confluentus were more broadly distributed than previously thought.

  11. Fungal and mussel protein sources in fish feed

    OpenAIRE

    Vidaković, Aleksandar

    2015-01-01

    Fungal and mussel protein sources in the diet of Eurasian perch (Perca fluviatilis), Arctic charr (Salvelinus alpinus) and rainbow trout (Oncorhynchus mykiss) and their effect on growth performance, nutrient utilisation, intestinal barrier function and post-prandial profiles of plasma amino acids and whole blood parameters were evaluated in this thesis. Apparent digestibility of dry matter, sum of amino acids and gross energy in experiment with Arctic charr decreased with dietary inclusio...

  12. Extensive feeding on sockeye salmon Oncorhynchus nerka smolts by bull trout Salvelinus confluentus during initial outmigration into a small, unregulated and inland British Columbia river.

    Science.gov (United States)

    Furey, N B; Hinch, S G; Lotto, A G; Beauchamp, D A

    2015-01-01

    Stomach contents were collected and analysed from 22 bull trout Salvelinus confluentus at the edge of the Chilko Lake and Chilko River in British Columbia, Canada, during spring outmigration of sockeye salmon Oncorhynchus nerka smolts. Twenty of the 22 (>90%) stomachs contained prey items, virtually all identifiable prey items were outmigrant O. nerka smolts and stomach contents represented a large portion (0·0-12·6%) of estimated S. confluentus mass. The results demonstrate nearly exclusive and intense feeding by S. confluentus on outmigrant smolts, and support recent telemetry observations of high disappearance rates of O. nerka smolts leaving large natural lake systems prior to entering high-order unregulated river systems. PMID:25494841

  13. Environmental assessment of freshwater ecosystems of the Sava River watershed and Cerkniško Lake, Slovenia, using the bioindicator species Fontinalis antipyretica: insights from stable isotopes and selected elements.

    Science.gov (United States)

    Mechora, Špela; Kanduč, Tjaša

    2016-06-01

    Ten locations in the Notranjska region, Slovenia, with different land use in the catchment (town, village and agricultural areas), including reference points with different geological composition considered as unpolluted sites, were sampled for water and aquatic moss to evaluate environmental assessment in fresh water systems of the Sava River watershed. Samples of fresh water and Fontinalis antipyretica were taken in all four seasons during the years 2010 and 2012. The water chemistry of the investigated locations was dominated by [Formula: see text], while concentrations of [Formula: see text] seasonally ranged from 2.1 to 6.4 mg L(-1) and at one of the reference sites did not exceed 1.3 mg L(-1). δ(13)CDIC values seasonally ranged from -13.3 to -8.1 ‰ and indicated waters dominated by degradation of organic matter and dissolution of carbonates. δ(13)Cplant values of F. antipyretica seasonally ranged from -45 to -32.9 ‰ and of δ(15)Nplant from -0.2 to 6.5 ‰. The higher δ(15)N value of 6.5 ‰ found in F. antipyretica was related to agricultural activity in the watershed. The content of minor and trace elements in F. antipyretica ranged from 4-38 µg g(-1) for Ni, 17-105 µg g(-1) for Zn, 2-28 µg g(-1) for Pb, 0.26-1.95 µg g(-1) for Cd, 4-27 µg g(-1) for Cu, 4-49 µg g(-1) for Cr, 1-6 µg g(-1) for As and 0.33-3.24 µg g(-1) for Se. The most polluted watershed was the Pšata stream (agricultural area, cattle farm with the highest concentration of nitrate in water) also with highest values for Ni, Cr, Pb, Zn and As.

  14. Bull Trout (Salvelinus Confluentus) Population and Habitat Surveys in the McKenzie and Middle Fork Willamette Basins, 2000 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Greg

    2000-11-28

    Prior to 1978, Dolly Varden Salvelinus malma were classified into an anadromous and interior form. Cavender (1978) classified the interior form as a distinct species, Salvelinus confluentus, the bull trout. Bull trout are large char weighing up to 18 kg and growing to over one meter in length (Goetz 1989). They are distinguished by a broad flat head, large downward curving maxillaries that extend beyond the eye, a well developed fleshy knob and a notch in the lower terminus of the snout, and light colored spots normally smaller than the pupil of the eye (Cavender 1978). Bull trout are found throughout northwestern North America from lat. 41{sup o}N to lat. 60{sup o}N. In Oregon, bull trout were once distributed throughout 12 basins in the Klamath and Columbia River systems including the Clackamas, Santiam, McKenzie and Middle Fork Willamette sub-basins west of the Cascades (Buchanan et al. 1997). However, it is believed bull trout have been extirpated from west of the Cascades with the exception of the McKenzie sub-basin. Before 1963, bull trout in the McKenzie sub-basin were a contiguous population from the mouth to Tamolitch Falls. Following the construction of Cougar and Trail Bridge Reservoirs there are three isolated populations: (1) mainstem McKenzie and tributaries from the mouth to Trail Bridge Reservoir. (2) mainstem McKenzie and tributaries above Trail Bridge Reservoir to Tamolitch Falls. (3) South Fork McKenzie and tributaries above Cougar Reservoir. The study area includes the three aforementioned McKenzie populations, and the Middle Fork Willamette and tributaries above Hills Creek Reservoir. We monitored bull trout populations in the McKenzie and Middle Fork Willamette basins using a combination of sampling techniques including: spawning surveys, standard pool counts, juvenile trapping, radio tracking, electronic fish counters, and a modified Hankin and Reeves protocol to estimate juvenile abundance and density. In addition, we continued to

  15. Distinguishing wild vs. stocked lake trout (Salvelinus namaycush) in Lake Ontario: Evidence from carbon and oxygen stable isotope values of otoliths

    Science.gov (United States)

    Schaner, T.; Patterson, W.P.; Lantry, B.F.; O'Gorman, R.

    2007-01-01

    We investigated the potential for using carbon and oxygen isotope values of otolith carbonate as a method to distinguish naturally produced (wild) lake trout (Salvelinus namaycush) from hatchery-reared lake trout in Lake Ontario. We determined δ 13C(CaCO3) and δ 18O(CaCO3) values of otoliths from juvenile fish taken from two hatcheries, and of otoliths from wild yearlings. Clear differences in isotope values were observed between the three groups. Subsequently we examined otoliths from large marked and unmarked fish captured in the lake, determining isotope values for regions of the otolith corresponding to the first year of life. Marked (i.e., stocked) fish showed isotope ratios similar to one of the hatchery groups, whereas unmarked fish, (wild fish or stocked fish that lost the mark) showed isotope ratios similar either to one of the hatchery groups or to the wild group. We interpret these data to suggest that carbon and oxygen isotope values can be used to determine the origin of lake trout in Lake Ontario, if a catalogue of characteristic isotope values from all candidate years and hatcheries is compiled.

  16. An ecological risk assessment of the acute and chronic toxicity of the herbicide picloram to the threatened bull trout (salvelinus confluentus) and the rainbow trout (onchorhyncus mykiss)

    Science.gov (United States)

    Fairchild, J.F.; Feltz, K.P.; Sappington, L.C.; Allert, A.L.; Nelson, K.J.; Valle, J.

    2009-01-01

    We conducted acute and chronic toxicity studies of the effects of picloram acid on the threatened bull trout (Salvelinus confluentus) and the standard coldwater surrogate rainbow trout (Oncorhynchus mykiss). Juvenile fish were chronically exposed for 30 days in a proportional flow-through diluter to measured concentrations of 0, 0.30, 0.60, 1.18, 2.37, and 4.75 mg/L picloram. No mortality of either species was observed at the highest concentration. Bull trout were twofold more sensitive to picloram (30-day maximum acceptable toxic concentration of 0.80 mg/L) compared to rainbow trout (30-day maximum acceptable toxic concentration of 1.67 mg/L) based on the endpoint of growth. Picloram was acutely toxic to rainbow trout at 36 mg/L (96-h ALC50). The acute:chronic ratio for rainbow trout exposed to picloram was 22. The chronic toxicity of picloram was compared to modeled and measured environmental exposure concentrations (EECs) using a four-tiered system. The Tier 1, worst-case exposure estimate, based on a direct application of the current maximum use rate (1.1 kg/ha picloram) to a standardized aquatic ecosystem (water body of 1-ha area and 1-m depth), resulted in an EEC of 0.73 mg/L picloram and chronic risk quotients of 0.91 and 0.44 for bull trout and rainbow trout, respectively. Higher-tiered exposure estimates reduced chronic risk quotients 10-fold. Results of this study indicate that picloram, if properly applied according to the manufacturer's label, poses little risk to the threatened bull trout or rainbow trout in northwestern rangeland environments on either an acute or a chronic basis. ?? 2008 Springer Science+Business Media, LLC.

  17. Investigations of Bull Trout (Salvelinus Confluentus), Steelhead Trout (Oncorhynchus Mykiss), and Spring Chinook Salmon (O. Tshawytscha) Interactions in Southeast Washington Streams. Final Report 1992.

    Energy Technology Data Exchange (ETDEWEB)

    Underwood, Keith D.

    1995-01-01

    The goal of this two year study was to determine if supplementation with hatchery reared steelhead trout (Oncorhynchus mykiss) and spring chinook salmon (O. tshawytscha) negatively impacted wild native bull trout (Salvelinus confluentus) through competitive interactions. Four streams with varying levels of fish supplementation activity were sampled in Southeast Washington. Tasks performed during this study were population density, relative abundance, microhabitat utilization, habitat availability, diet analysis, bull trout spawning ground surveys, radio telemetry of adult bull trout, and growth analysis. Results indicate that bull trout overlapped geographically with the supplemented species in each of the study streams suggesting competition among species was possible. Within a stream, bull trout and the supplemented species utilized dissimilar microhabitats and microhabitat utilization by each species was the same among streams suggesting that there was no shifts in microhabitat utilization among streams. The diet of bull trout and O. mykiss significantly overlapped in each of the study streams. The stream most intensely supplemented contained bull trout with the slowest growth and the non-supplemented stream contained bull trout with the fastest growth. Conversely, the stream most intensely supplemented contain steelhead with the fastest growth and the non-supplemented stream contained steelhead with the slowest growth. Growth indicated that bull trout may have been negatively impacted from supplementation, although other factors may have contributed. At current population levels, and current habitat quantity and quality, no impacts to bull trout as a result of supplementation with hatchery reared steelhead trout and spring chinook salmon were detected. Project limitations and future research recommendations are discussed.

  18. Investigations of bull trout (Salvelinus confluentus), steelhead trout (Oncorhynchus mykiss), and spring chinook salmon (O. tshawytscha) interactions in Southeast Washington streams. Final report 1992

    International Nuclear Information System (INIS)

    The goal of this two year study was to determine if supplementation with hatchery reared steelhead trout (Oncorhynchus mykiss) and spring chinook salmon (O. tshawytscha) negatively impacted wild native bull trout (Salvelinus confluentus) through competitive interactions. Four streams with varying levels of fish supplementation activity were sampled in Southeast Washington. Tasks performed during this study were population density, relative abundance, microhabitat utilization, habitat availability, diet analysis, bull trout spawning ground surveys, radio telemetry of adult bull trout, and growth analysis. Results indicate that bull trout overlapped geographically with the supplemented species in each of the study streams suggesting competition among species was possible. Within a stream, bull trout and the supplemented species utilized dissimilar microhabitats and microhabitat utilization by each species was the same among streams suggesting that there was no shifts in microhabitat utilization among streams. The diet of bull trout and O. mykiss significantly overlapped in each of the study streams. The stream most intensely supplemented contained bull trout with the slowest growth and the non-supplemented stream contained bull trout with the fastest growth. Conversely, the stream most intensely supplemented contain steelhead with the fastest growth and the non-supplemented stream contained steelhead with the slowest growth. Growth indicated that bull trout may have been negatively impacted from supplementation, although other factors may have contributed. At current population levels, and current habitat quantity and quality, no impacts to bull trout as a result of supplementation with hatchery reared steelhead trout and spring chinook salmon were detected. Project limitations and future research recommendations are discussed

  19. Assessing the impacts of river regulation on native bull trout (Salvelinus confluentus) and westslope cutthroat trout (Oncorhynchus clarkii lewisi) habitats in the upper Flathead River, Montana, USA

    Science.gov (United States)

    Muhlfeld, Clint C.; Jones, Leslie A.; Kotter, D.; Miller, William J.; Geise, Doran; Tohtz, Joel; Marotz, Brian

    2012-01-01

    Hungry Horse Dam on the South Fork Flathead River, Montana, USA, has modified the natural flow regimen for power generation, flood risk management and flow augmentation for anadromous fish recovery in the Columbia River. Concern over the detrimental effects of dam operations on native resident fishes prompted research to quantify the impacts of alternative flow management strategies on threatened bull trout (Salvelinus confluentus) and westslope cutthroat trout (Oncorhynchus clarkii lewisi) habitats. Seasonal and life‐stage specific habitat suitability criteria were combined with a two‐dimensional hydrodynamic habitat model to assess discharge effects on usable habitats. Telemetry data used to construct seasonal habitat suitability curves revealed that subadult (fish that emigrated from natal streams to the river system) bull trout move to shallow, low‐velocity shoreline areas at night, which are most sensitive to flow fluctuations. Habitat time series analyses comparing the natural flow regimen (predam, 1929–1952) with five postdam flow management strategies (1953–2008) show that the natural flow conditions optimize the critical bull trout habitats and that the current strategy best resembles the natural flow conditions of all postdam periods. Late summer flow augmentation for anadromous fish recovery, however, produces higher discharges than predam conditions, which reduces the availability of usable habitat during this critical growing season. Our results suggest that past flow management policies that created sporadic streamflow fluctuations were likely detrimental to resident salmonids and that natural flow management strategies will likely improve the chances of protecting key ecosystem processes and help to maintain and restore threatened bull trout and westslope cutthroat trout populations in the upper Columbia River Basin.

  20. On the relative effect of spawning asynchrony, sperm quantity, and sperm quality on paternity under sperm competition in an external fertilizer

    OpenAIRE

    Egeland, Torvald B.; Rudolfsen, Geir; Nordeide, Jarle T.; Folstad, Ivar

    2015-01-01

    How much of a fitness benefit is obtained by dominant males of external fertilizers from releasing ejaculates in synchrony with female egg-release when engaging in sperm competition, and what is the most important sperm trait for paternity in these situations? The Arctic charr (Salvelinus alpinus) is an external fertilizer experiencing intense male-male competition over reproductive opportunities including sperm competition. To compensate for their disadvantage the sneaker male...

  1. On the relative effect of spawning asynchrony, sperm quantity and sperm quality on paternity under sperm competition in an external fertilizer

    OpenAIRE

    Torvald Blikra Egeland; Geir eRudolfsen; Jarle Tryti Nordeide; Ivar eFolstad

    2015-01-01

    How much of a fitness benefit is obtained by dominant males of external fertilizers from releasing ejaculates in synchrony with female egg-release when engaging in sperm competition, and what is the most important sperm trait for paternity in these situations? The Arctic charr (Salvelinus alpinus) is an external fertilizer experiencing intense male-male competition over reproductive opportunities including sperm competition. To compensate for their disadvantage the sneaker males, which often ...

  2. An Evaluation of the Relative Performance of Diploid Versus Triploid Brook Trout with Consideration of the Influence of Lake Characteristics

    OpenAIRE

    Dean, Andy

    2014-01-01

    Triploid (sterile) trout potentially offer a more risk-averse option for stocking popular non-native sport fish; however the relative performance (e.g., survival and growth) of triploid versus diploid fish in natural settings is not well understood. I evaluated the relative performance of triploid versus diploid brook trout (Salvelinus fontinalis) stocked in high mountain Uinta lakes in response to food availability and lake morphology. I chose a set of 9 lakes that included a range of elevat...

  3. Movement Patterns and Multi-Scale Factors That Influence Exotic Brook Trout And Endemic Bonneville Cutthroat Trout Distribution And Abundance In The Mill Creek Drainage, Utah

    OpenAIRE

    Nadolski, Benjamin Keith

    2008-01-01

    Introduced brook trout (Salvelinus fontinalis) are implicated as a primary factor leading to the decline in distribution and abundance of native cutthroat trout (Oncorhynchus clarkii). However, not all introductions are successful, suggesting local conditions influence the success of invasions. Therefore, I sought to determine the multi-scale factor(s) that influence brook trouts’ invasion success of native Bonneville cutthroat trout (Oncorhynchus clarkii utah) habitats in Mill Creek, Utah. I...

  4. Do native brown trout and non-native brook trout interact reproductively?

    OpenAIRE

    Cucherousset, Julien; Aymes, J.-C.; Poulet, Nicolas; Santoul, Frédéric; Céréghino, Régis

    2008-01-01

    International audience Reproductive interactions between native and non-native species of fish have received little attention compared to other types of interactions such as predation or competition for food and habitat. We studied the reproductive interactions between non-native brook trout (Salvelinus fontinalis) and native brown trout (Salmo trutta) in a Pyrenees Mountain stream (SW France). We found evidence of significant interspecific interactions owing to consistent spatial and temp...

  5. Movement and Habitat Use of Bonneville Cutthroat Trout (Oncorhynchus Clarki Utah): A Case Study In the Temple Fork Watershed

    OpenAIRE

    Lokteff, Ryan L.

    2014-01-01

    Movement patterns and habitat use of Bonneville cutthroat trout (Oncorhynchus clarki utah) in tributaries of the Logan River watershed are greatly aected by habitat alterations created by North American Beaver (Castor canadensis). Evaluation of cutthroat trout habitat use in these watersheds is also complicated by biotic interactions with invasive brown trout (Salmo trutta) and brook trout (Salvelinus fontinalis). My objectives in this thesis were to 1.) Evaluate the passage of beaver dams by...

  6. Flodpärlmusslans status i Laxtjärnbäcken : Effekter på flodpärlmusslan av sedimentbelastning och förekomst av bäckröding

    OpenAIRE

    Pålsson, Anders

    2011-01-01

    The aim of this present study was to determine and evaluate whether the presence of brooktrout (Salvelinus fontinalis) and sediment load may be a threat against the reproduction anddistribution of freshwater pearl mussel (Margaritifera margaritifera) in a creek located innorthern Sweden. Freshwater pearl mussel is an endangered species and is dependent ofbrown trout (Salmo trutta) to reproduce. Therefore there are concerns of indirect effects onthe population of pearl mussel by competition be...

  7. The Movements of Ferox Trout, Salmo trutta, in a Scottish Highland Freshwater Loch

    OpenAIRE

    Thorne, Alastair; MacDonald, Alisdair; Thorley, Joseph; Johnstone, Alastair

    2015-01-01

    Ferox trout (Salmo trutta) are the top fish predators in many Scottish lochs feeding on smaller trout and Arctic charr (Salvelinus alpinus) – their main prey species. Although once considered a separate species, ferox trout are brown trout which have switched to a mainly piscivorous diet. The diet switch not only boosts growth (the current UK rod caught record weight is 14.4kg), but also adds to longevity (the oldest confirmed UK ferox was 23 years old). The main aim of the study d...

  8. Lake bathymetry and species occurrence predict the distribution of a lacustrine apex predator.

    Science.gov (United States)

    Hughes, M R; Dodd, J A; Maitland, P S; Adams, C E

    2016-04-01

    This study examined the abiotic and biotic characteristics of ecosystems that allow expression of a life history called ferox trout, the colloquial name given to brown trout Salmo trutta adopting a piscivorous life history strategy, an apex predator in post-glacial lakes in northern Europe. One hundred and ninety-two lakes in Scotland show evidence of currently, or historically, supporting ferox S. trutta; their presence was predicted in logistic models by larger and deeper lakes with a large catchment that also support populations of Arctic charr Salvelinus alpinus. PMID:26899559

  9. Radioactive contamination of fishes in lake and streams impacted by the Fukushima nuclear power plant accident

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimura, Mayumi, E-mail: yoshi887@ffpri.affrc.go.jp [Kansai Research Center, Forestry and Forest Products Research Institute, Nagaikyuutaro 68, Momoyama, Fushimi, Kyoto 612-0855 (Japan); Yokoduka, Tetsuya [Tochigi Prefectural Fisheries Experimental Station, Sarado 2599, Ohtawara, Tochigi 324-0404 (Japan)

    2014-06-01

    The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in March 2011 emitted radioactive substances into the environment, contaminating a wide array of organisms including fishes. We found higher concentrations of radioactive cesium ({sup 137}Cs) in brown trout (Salmo trutta) than in rainbow trout (Oncorhynchus nerka), and {sup 137}Cs concentrations in brown trout were higher in a lake than in a stream. Our analyses indicated that these differences were primarily due to differences in diet, but that habitat also had an effect. Radiocesium concentrations ({sup 137}Cs) in stream charr (Salvelinus leucomaenis) were higher in regions with more concentrated aerial activity and in older fish. These results were also attributed to dietary and habitat differences. Preserving uncontaminated areas by remediating soils and releasing uncontaminated fish would help restore this popular fishing area but would require a significant effort, followed by a waiting period to allow activity concentrations to fall below the threshold limits for consumption. - Highlight: • Concentration of {sup 137}Cs in brown trout was higher than in rainbow trout. • {sup 137}Cs concentration of brown trout in a lake was higher than in a stream. • {sup 137}Cs concentration of stream charr was higher in region with higher aerial activity. • Concentration of {sup 137}Cs in stream charr was higher in older fish. • Difference of contamination among fishes was due to difference in diet and habitat.

  10. Radioactive contamination of fishes in lake and streams impacted by the Fukushima nuclear power plant accident

    International Nuclear Information System (INIS)

    The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in March 2011 emitted radioactive substances into the environment, contaminating a wide array of organisms including fishes. We found higher concentrations of radioactive cesium (137Cs) in brown trout (Salmo trutta) than in rainbow trout (Oncorhynchus nerka), and 137Cs concentrations in brown trout were higher in a lake than in a stream. Our analyses indicated that these differences were primarily due to differences in diet, but that habitat also had an effect. Radiocesium concentrations (137Cs) in stream charr (Salvelinus leucomaenis) were higher in regions with more concentrated aerial activity and in older fish. These results were also attributed to dietary and habitat differences. Preserving uncontaminated areas by remediating soils and releasing uncontaminated fish would help restore this popular fishing area but would require a significant effort, followed by a waiting period to allow activity concentrations to fall below the threshold limits for consumption. - Highlight: • Concentration of 137Cs in brown trout was higher than in rainbow trout. • 137Cs concentration of brown trout in a lake was higher than in a stream. • 137Cs concentration of stream charr was higher in region with higher aerial activity. • Concentration of 137Cs in stream charr was higher in older fish. • Difference of contamination among fishes was due to difference in diet and habitat

  11. 大鳞副泥鳅雄核单倍体的早期发育%OBSERVATION ON THE EARLY DEVELOPMENT OF ANGROGENETIC HAPLOID IN PARAMISGURNUS DABRYANUS

    Institute of Scientific and Technical Information of China (English)

    赵振山; 吴清江; 刘辉宇; 高贵琴

    2000-01-01

    @@ 目前,有关鱼类雄核发育的研究已见于川鲽(Platichthys flesus)、马苏大麻哈鱼(Oncorhynchus masou)、虹鳟(Oncorhynchus mykiss)、红点溪鳟(Salvelinus fontinalis)、鲤鱼(Cyprnus carpio)、尼罗罗非鱼(Oreochromis niloticus)、泥鳅(Misgurnus anguillicaudatus)、斑马鱼(Danio rerio)等(Purdom,1969;Arai et al., 1979; Scheerer et al., 1991; May et al., 1988; Bongers et al., 1994;Grunina et al., 1990; Meyers, 1995; Masaoka et al., 1995; 赵振山等,1998;Corley-Smith et al., 1996).

  12. Vliv alternativních krmiv na růst, výtěžnost a senzorické vlastnosti masa lososovitých ryb.

    OpenAIRE

    PFLUG, Róbert

    2013-01-01

    The bachelor thesis evaluates the impact of alternative feed on growth, yield and sensory evaluation of flesh of salmonids. The technology "finishing feeding" and its impact on these indicators was evaluated by a feeding test conducted in trout farm in Annin (Klatovské rybářství a.s.). The experimental species was brook trout (Salvelinus fontinalis L.) with average weight of 156 ? 4,91 g. The test was carried out for 135 days and there were 2 diets. Diet A (rapeseed oil, RO) or B (fish oil, F...

  13. Handling and Storage Procedures Have Variable Effects on Fatty Acid Content in Fishes with Different Lipid Quantities

    Science.gov (United States)

    Rudy, Martina D.; Kainz, Martin J.; Graeve, Martin; Colombo, Stefanie M.

    2016-01-01

    It is commonly assumed that the most accurate data on fatty acid (FA) contents are obtained when samples are analyzed immediately after collection. For logistical reasons, however, this is not always feasible and samples are often kept on ice or frozen at various temperatures and for diverse time periods. We quantified temporal changes of selected FA (μg FAME per mg tissue dry weight) from 6 fish species subjected to 2 handling and 3 storage methods and compared them to FA contents from muscle tissue samples that were processed immediately. The following species were investigated: Common Carp (Cyprinus carpio), Freshwater Drum (Aplodinotus grunniens), Channel Catfish (Ictalurus punctatus), Antarctic Eelpout (Pachycara brachycephalum), Rainbow Trout (Oncorhynchus mykiss) and Arctic Charr (Salvelinus alpinus). The impact of storage method and duration of storage on FA contents were species-specific, but not FA-specific. There was no advantage in using nitrogen gas for tissue samples held on ice for 1 week; however, holding tissue samples on ice for 1 week resulted in a loss of FA in Charr. In addition, most FA in Trout and Charr decreased in quantity after being stored between 3 and 6 hours on ice. Freezer storage temperature (-80 or -20°C) also had a significant effect on FA contents in some species. Generally, we recommend that species with high total lipid content (e.g. Charr and Trout) should be treated with extra caution to avoid changes in FA contents, with time on ice and time spent in a freezer emerging as significant factors that changed FA contents. PMID:27479304

  14. Geosmin causes off-flavour in arctic charr in recirculating aquaculture systems

    Science.gov (United States)

    The “earthy” and “muddy” off-flavors in pond-reared fish are due to the presence of geosmin or 2-methylisoborneol (MIB) in the flesh of the fish. Similar off-flavors have been reported in fish raised in recirculating aquaculture systems (RAS); however, little information is available regarding the ...

  15. Short-and long term niche segregation and individual specialization of brown trout (Salmo trutta) in species poor Faroese lakes

    DEFF Research Database (Denmark)

    Brodersen, Jakob; Malmquist, Hilmar J.; Landkildehus, Frank;

    2012-01-01

    Trophic niche divergence is considered to be a major process by which species coexistence is facilitated. When studying niche segregation in lake ecosystems, we tend to view the niche on a one-dimensional pelagic-littoral axis. In reality, however, the niche use may be more complex and individual...... living in allopatry or in sympatry with Arctic charr (Salvelinus alpinus). Diet analyses revealed, however, that niche-segregation may be more complex than described on a one-dimensional pelagic-littoral axis. Trout from both littoral and offshore benthic habitats had in the presence of sticklebacks a...... fidelity to a niche may be variable both between and within populations. In order to study this complexity, relative simple systems with few species are needed. In this paper, we study how competitor presence affects the resource use of brown trout (Salmo trutta) in 11 species-poor Faroese lakes by...

  16. Bilan des introductions de salmonidés dans les lacs et ruisseaux d'altitude des Hautes-Pyrénées

    Directory of Open Access Journals (Sweden)

    DELACOSTE M.

    1997-01-01

    Full Text Available Les introductions de Salmonidés ont été importantes au cours des 60 dernières années dans les lacs et ruisseaux d'altitude des Hautes-Pyrénées. Six espèces de Salmonidés ont été introduites dans des milieux qui, pour la plupart, étaient vierges de populations piscicoles : la truite commune (Salmo trutta L., la truite arc-en-ciel (Oncorhynchus mykiss Walbaum, l'omble de fontaine (Salvelinus fontinalis Mitchill, l'omble chevalier (Salvelinus alpinus L., le cristivomer (Salvelinus namaycush Walbaum et le splake (Salvelinus fontinalis x Salvelinus namaycush. Dans de très nombreux cas, ces introductions ont abouti à des acclimatations. En revanche, les naturalisations sont beaucoup plus rares. Seules les espèces lacustres (cristivomer et omble chevalier se sont naturalisées dans la majorité des lacs où elles ont été introduites. Les conditions de reproduction constituent le facteur clé permettant d'expliquer la naturalisation des espèces. En ruisseau, il faut y ajouter la compétition avec l'espèce indigène (la truite commune, la pression halieutique ainsi que les conditions hivernales très rigoureuses. Les incidences écologiques des introductions sur les populations de truites communes indigènes sont faibles. En revanche, elles ne sont pas négligeables pour les populations de batraciens. Cette politique d'introduction a largement participé au développement de l'halieutisme dans ces milieux d'altitude. En cela, les introductions ont parfaitement répondu aux objectifs halieutiques qu'on leur avait fixés. L'acquisition de connaissances sur l'ensemble de la chaîne pyrénéenne constitue aujourd'hui une étape incontournable pour une politique de gestion globale des introductions.

  17. Synchronizace ovulace jikernaček sivena amerického a pstruha duhového

    OpenAIRE

    JANKOVÝCH, Antonín

    2012-01-01

    The effect of GnRH analogue on synchronizing ovulation in the female brook charr and rainbow trout was assessed in 3 experiments (2010- brook charr, 2011-brook charr+rainbow trout). Prior to the onset of the spawning season females of brook charr and rainbow trout were hormonaly stimulated.

  18. Do native brown trout and non-native brook trout interact reproductively?

    Science.gov (United States)

    Cucherousset, J.; Aymes, J. C.; Poulet, N.; Santoul, F.; Céréghino, R.

    2008-07-01

    Reproductive interactions between native and non-native species of fish have received little attention compared to other types of interactions such as predation or competition for food and habitat. We studied the reproductive interactions between non-native brook trout ( Salvelinus fontinalis) and native brown trout ( Salmo trutta) in a Pyrenees Mountain stream (SW France). We found evidence of significant interspecific interactions owing to consistent spatial and temporal overlap in redd localizations and spawning periods. We observed mixed spawning groups composed of the two species, interspecific subordinate males, and presence of natural hybrids (tiger trout). These reproductive interactions could be detrimental to the reproduction success of both species. Our study shows that non-native species might have detrimental effects on native species via subtle hybridization behavior.

  19. Exposure-related effects of Pseudomonas fluorescens, strain CL145A, on coldwater, coolwater, and warmwater fish

    Science.gov (United States)

    Luoma, James A.; Weber, Kerry L.; Denise A. Mayer

    2015-01-01

    The exposure-related effects of a commercially prepared spray-dried powder (SDP) formulation of Pseudomonas fluorescens, strain CL145A, were evaluated on coldwater, coolwater, and warmwater fish endemic to the Great Lakes and Upper Mississippi River Basins. Nine species of young-of-the-year fish were exposed to SDP for 24 hours by using continuous-flow, serial-dilution exposure systems at temperatures of 12 degrees Celsius (°C; 2 species; Oncorhynchus mykiss [rainbow trout] and Salvelinus fontinalis [brook trout]), 17 °C (3 species; Perca flavescens [yellow perch], Sander vitreus [walleye], and Acipenser fulvescens [lake sturgeon]), or 22 °C (4 species; Micropterus salmoides [largemouth bass], Micropterus dolomieu [smallmouth bass], Lepomis macrochirus [bluegill sunfish], and Ictalurus punctatus [channel catfish]).

  20. Component population study of Acanthocephalus tumescens (Acanthocephala) in fishes from Lake Moreno, Argentina.

    Science.gov (United States)

    Rauque, Carlos A; Viozzi, Gustavo P; Semenas, Liliana G

    2003-03-01

    Seasonal samples of all fish species from Lake Moreno were taken in order to determine the presence of paratenia, to evaluate the status of the hosts and to characterise the transmission of Acanthocephalus tumescens (von Linstow, 1896) at the component population level. Prevalence, mean abundance, mean intensity, numbers of gravid females, relative abundance of the different fish species, relative output of eggs and relative flow rates for each host species were computed. Acanthocephalus tumescens showed low host specificity, successfully parasitizing six out of eight fish species present in the lake. No paratenic infection was registered. If prevalence, mean abundance, and number of gravid females are considered, host species can be placed in a continuum from the most to least suitable as follows: Galaxias platei Steindachner, Diplomystes viedmensis (Mac Donagh), Oncorhynchus mykiss (Walbaum), Salvelinus fontinalis (Mitchill), Percichthys trucha (Cuvier et Valenciennes) and Galaxias maculatus (Jenyns). However, when parasite flow rates and egg output were calculated, including relative abundance of each fish species, the continuum was rearranged as follows: P. trucha, O. mykiss, G. platei / G. maculatus, S. fontinalis and D. viedmensis. The first four species would be the main contributors to the population of A. tumescens in this lake, P. trucha being the major one. Different regulatory and non-regulatory mechanisms are suggested. PMID:12735727

  1. Role of climate and invasive species in structuring trout distributions in the interior Columbia River Basin, USA

    Science.gov (United States)

    Wenger, Seth J.; Isaak, Daniel J.; Dunham, Jason B.; Fausch, Kurt D.; Luce, Charles H.; Neville, Helen M.; Rieman, Bruce E.; Young, Michael K.; Nagel, David E.; Horan, Dona L.; Chandler, Gwynne L.

    2011-01-01

    Recent and projected climate warming trends have prompted interest in impacts on coldwater fishes. We examined the role of climate (temperature and flow regime) relative to geomorphology and land use in determining the observed distributions of three trout species in the interior Columbia River Basin, USA. We considered two native species, cutthroat trout (Oncorhynchus clarkii) and bull trout (Salvelinus confluentus), as well as nonnative brook trout (Salvelinus fontinalis). We also examined the response of the native species to the presence of brook trout. Analyses were conducted using multilevel logistic regression applied to a geographically broad database of 4165 fish surveys. The results indicated that bull trout distributions were strongly related to climatic factors, and more weakly related to the presence of brook trout and geomorphic variables. Cutthroat trout distributions were weakly related to climate but strongly related to the presence of brook trout. Brook trout distributions were related to both climate and geomorphic variables, including proximity to unconfined valley bottoms. We conclude that brook trout and bull trout are likely to be adversely affected by climate warming, whereas cutthroat trout may be less sensitive. The results illustrate the importance of considering species interactions and flow regime alongside temperature in understanding climate effects on fish.

  2. Kalispel Resident Fish Project : Annual Report, 1995.

    Energy Technology Data Exchange (ETDEWEB)

    Maroney, Joseph; Donley, Christopher; Scott, Jason; Lockwood, Jr., Neil

    1997-06-01

    In 1995 the Kalispel Natural Resource Department (KNRD) in conjunction with the Washington Department of Fish and Wildlife (WDFW) initiated the implementation of a habitat and population enhancement project for bull trout (Salvelinus confluentus), westslope cutthroat trout (Oncorhynchus clarki lewisi) and largemouth bass (Micropterus salmoides). Habitat and population assessments were conducted in seven tributaries of the Box Canyon reach of the Pend Oreille River. Assessments were used to determine the types and quality of habitat that were limiting to native bull trout and cutthroat trout populations. Assessments were also used to determine the effects of interspecific competition within these streams. A bull trout and brook trout (Salvelinus fontinalis) hybridization assessment was conducted to determine the degree of hybridization between these two species. Analysis of the habitat data indicated high rates of sediment and lack of wintering habitat. The factors that contribute to these conditions have the greatest impact on habitat quality for the tributaries of concern. Population data suggested that brook trout have less stringent habitat requirements; therefore, they have the potential to outcompete the native salmonids in areas of lower quality habitat. No hybrids were found among the samples, which is most likely attributable to the limited number of bull trout. Data collected from these assessments were compiled to develop recommendations for enhancement measures. Recommendations for restoration include riparian planting and fencing, instream structures, as well as, removal of non-native brook trout to reduce interspecific competition with native salmonids in an isolated reach of Cee Cee Ah Creek.

  3. On the relative effect of spawning asynchrony, sperm quantity and sperm quality on paternity under sperm competition in an external fertilizer

    Directory of Open Access Journals (Sweden)

    Torvald Blikra Egeland

    2015-07-01

    Full Text Available How much of a fitness benefit is obtained by dominant males of external fertilizers from releasing ejaculates in synchrony with female egg-release when engaging in sperm competition, and what is the most important sperm trait for paternity in these situations? The Arctic charr (Salvelinus alpinus is an external fertilizer experiencing intense male-male competition over reproductive opportunities including sperm competition. To compensate for their disadvantage the sneaker males, which often spawn out of synchrony with the female, produce more and faster sperm than the guarding males. We used controlled in vitro fertilization trials with experimentally produced dominant and subordinate, sneaker males to test what effect relative synchrony in gamete release, sperm quality (i.e., motility and velocity and sperm quantity have on a male’s fertilization success in pair-wise sperm competitions. When the sneaker males released ejaculates after the guarding male there was no overall difference in fertilization success. The quality (i.e., motility and velocity of a male’s sperm relative to that of the competing male was the best predictor of male fertilization success regardless of their mating tactic and spawning synchrony. The relative number of sperm cells also had an effect on fertilization success, but mainly when the dominant and sneaker male ejaculated synchronously. Our close imitation of natural sperm competition in charr shows that the sneaker males of external fertilizing species may fully compensate for their disadvantaged mating role by producing ejaculates of higher quality - an adjustment strangely not met by dominants.

  4. Plastic resource polymorphism: effects of resource availability on Arctic char ( Salvelinus alpinus ) morphology

    NARCIS (Netherlands)

    J. Andersson; P. Bystrom; L. Persson; A.M. de Roos

    2005-01-01

    6. Abstract (optional): Resource polymorphism has been suggested to be a platform for speciation. In some cases resource polymorphism depends on phenotypic plasticity but in other cases on genetic differences between morphotypes, which in turn has been suggested to be the ongoing development of a sp

  5. Teleost reproduction: Aspects of Arctic char (Salvelinus alpinus) oocyte growth and maturation.

    OpenAIRE

    Berg, Håkan

    2003-01-01

    In all vertebrate species, reproduction is a hormonally controlled process, important for growth and maturation of gonads and germ cells. Production of functional germ cells is of outmost importance to secure the survival of a species. Fish comprises 50% of the known vertebrates and are found in aquatic habitats all over the world. Even though fish have evolved a wide variety of morphological and physiological characteristics, due to large differences in the living environment, the growth an ...

  6. In vitro immune functions in thiamine-replete and -depleted lake trout (Salvelinus namaycush)

    Science.gov (United States)

    Ottinger, Christopher A.; Honeyfield, Dale C.; Densmore, Christine L.; Iwanowicz, Luke R.

    2014-01-01

    In this study we examined the impacts of in vivo thiamine deficiency on lake trout leukocyte function measured in vitro. When compared outside the context of individual-specific thiamine concentrations no significant differences were observed in leukocyte bactericidal activity or in concanavalin A (Con A), and phytohemagglutinin-P (PHA-P) stimulated leukocyte proliferation. Placing immune functions into context with the ratio of in vivo liver thiamine monophosphate (TMP – biologically inactive form) to thiamine pyrophosphate (TPP – biologically active form) proved to be the best indicator of thiamine depletion impacts as determined using regression modeling. These observed relationships indicated differential effects on the immune measures with bactericidal activity exhibiting an inverse relationship with TMP to TPP ratios, Con A stimulated mitogenesis exhibiting a positive relationship with TMP to TPP ratios and PHA-P stimulated mitogenesis exhibiting no significant relationships. In addition, these relationships showed considerable complexity which included the consistent observation of a thiamine-replete subgroup with characteristics similar to those seen in the leukocytes from thiamine-depleted fish. When considered together, our observations indicate that lake trout leukocytes experience cell-type specific impacts as well as an altered physiologic environment when confronted with a thiamine-limited state.

  7. Mercury in the biotic compartments of Northwest Patagonia lakes, Argentina.

    Science.gov (United States)

    Rizzo, A; Arcagni, M; Arribére, M A; Bubach, D; Guevara, S Ribeiro

    2011-06-01

    We report on total mercury (THg) concentrations in the principal components of food webs of selected Northern Patagonia Andean Range ultraoligotrophic lakes, Argentina. The THg contents were determined using Instrumental Neutron Activation Analysis in muscle and liver of four fish species occupying the higher trophic positions (the introduced Salmo trutta, Oncorhynchus mykiss and Salvelinus fontinalis, and the native Percichthys trucha) accounted for eight lakes belonging to Nahuel Huapi and Los Alerces National Parks. We studied the food web components of both the West and East branches of Lake Moreno, including benthic primary producers such as biofilm, mosses, and macrophytes, three plankton fractions, fish, riparian tree leaves, and benthic invertebrates, namely decapods, molluscs, insect larvae, leeches, oligochaetes, and amphipods. Mercury concentrations in fish muscle varied in a wide range, from less than 0.05 to 4 μg g(-1) dry weight (DW), without a distribution pattern among species but showing higher values for P. trucha and S. fontinalis, particularly in Lake Moreno. The THg contents of the food web components of Lake Moreno varied within 4 orders of magnitude, with the lower values ranging from 0.01 to 0.5 μg g(-1) DW in tree leaves, some macrophytes, juvenile salmonids or benthic macroinvertebrates, and reaching concentrations over 200 μg g(-1) DW in the plankton. Juvenile Galaxias maculatus caught in the pelagic area presented the highest THg contents of all fish sampled, reaching 10 μg g(-1) DW, contents that could be associated with the high THg concentrations in plankton since it is their main food source. Although Lake Moreno is a system without local point sources of contamination, situated in a protected area, some benthic organisms presented high THg contents when compared with those from polluted ecosystems. PMID:21421254

  8. Fontinalis antipyretica as a bioindicator of environmental conditions in freshwater ecosystem from Sava River watershed and Cerknişko Lake, Slovenia

    Science.gov (United States)

    Kanduč, Tjaša; Mechora, Špela; Stibilj, Vekoslava

    2014-05-01

    Polluted waters recharging from agriculture water systems into watersheds have influence on water quality and living habitat. Stable isotopes of carbon and nitrogen in combination with other minor and trace elements are often used to trace biogeochemical processes and contamination of water systems. The aim of the study was to assess state of environment with minor and trace elements and stable isotopes of C and N in selected Slovenian streams. Ten locations in Notranjska region, Slovenia, with different land use in the catchment (town, village, agricultural areas, farms, dairy farms), including reference point considered as non-polluted site, were sampled. Samples of water and aquatic moss F. antipyretica in Slovenian fresh waters were taken in all four seasons during years 2010 and 2012, but for stable isotope analyses of C and N only in three seasons during years 2010 and 2011. The water chemistry of investigated locations is dominated by hydrogen carbonate - calcium - magnesium, concentrations of nitrate seasonally range from 2.07 mg/l to 6.4 mg/l and at reference site does not exceed 1.3 mg/l. Total alkalinity of water at investigated locations ranges from 2.9 to 6.02 mM. The pH of investigated water range from 7.2 to 8.5, waters are saturated with oxygen (up to 134%) and conductivity ranges from 295 to 525 mikroS/cm, while at reference site conductivity is up to 180 mikroS/cm. The content of minor and trace elements in F. antipyretica ranged for Ni 4-38 mikrog/g, Zn 17-105 mikrog/g, Pb 2-28 mikrog/g, Cd 220-1953 ng/g, Cu 4-27 mikrog/g, Cr 4-49 mikrog/g, As 1-6 mikrog/g and Se 0.33-3.24 mikrog/g. The most polluted watershed was Pšata stream (agricultural areas, cattle farm) with highest values for Ni, Cr, Pb, Zn and As. The highest content of Se, was found in village (dairy farms) in Žerovniščica stream. The highest values were measured in February and October. Isotopic composition of dissolved inorganic carbon seasonally range from -13.3 to -8.1‰, and indicate waters dominated by degradation of organic matter and dissolution of carbonates. At the reference point average measured isotopic composition of dissolved inorganic carbon value is -2.7‰ which confirmed that this is a non-polluted site. Isotopic composition of carbon of F. antipyretica seasonally ranges from -45 to -32.9‰ and isotopic composition of nitrogen from -0.2‰ to 6.5‰, respectively. In comparison to C3 terrestrial plants F. antipyretica has more negative isotopic composition of carbon value, which is probably related with the difference in CO2 plant fixation and depends on isotopic composition of dissolved inorganic carbon in water, which is primarily controlled by geological composition and soil thickness in the watershed. Higher isotopic composition of nitrogen value found in F. antipyretica is related to agricultural activity in watershed, while at the reference site measured isotopic composition of nitrogen value is -4.1 ‰. From our study it is evident that isotopic composition of carbon and nitrogen is useful tracer of natural and anthropogenic inputs from terrestrial (fertilizing, sewage sludge) to water system.

  9. Flavobacterium psychrophilum Infections in Salmonid Broodstock and Hatchery-Propagated Stocks of the Great Lakes Basin.

    Science.gov (United States)

    Van Vliet, Danielle; Loch, Thomas P; Faisal, Mohamed

    2015-12-01

    Bacterial coldwater disease (BCWD), caused by Flavobacterium psychrophilum, threatens wild and propagated salmonids worldwide and leads to substantial economic losses. In addition to being horizontally transmitted, F. psychrophilum can be passed from infected parents to their progeny, furthering the negative impacts of this pathogen. In Michigan, both feral and captive salmonid broodstocks are the gamete sources used in fishery propagation efforts. A 5-year study was initiated to follow the prevalence of systemic F. psychrophilum infections in feral broodstocks of four species (steelhead Oncorhynchus mykiss [potadromous Rainbow Trout]; Coho Salmon O. kisutch; Chinook Salmon O. tshawytscha; and Atlantic Salmon Salmo salar) residing in three Great Lakes watersheds. Additionally, captive broodstocks of four species (Rainbow Trout, Brown Trout Salmo trutta, Lake Trout Salvelinus namaycush, and Brook Trout Salvelinus fontinalis) maintained at two facilities were assessed for the presence of F. psychrophilum. The resultant offspring from each broodstock population were sampled for F. psychrophilum infections multiple times throughout hatchery residency. Using selective flavobacterial culture and PCR confirmation, F. psychrophilum was detected in all broodstocks except the captive Lake Trout and Brook Trout. Logistic regression analysis demonstrated that among the infected feral broodstocks, Chinook Salmon from the Lake Michigan watershed had the highest prevalence of systemic F. psychrophilum infection (mean = 63.2%). Among the captive broodstocks, the Gilchrist Creek strain of Brown Trout had the highest infection prevalence (mean = 5%). Collectively, the captive broodstocks were found to have significantly lower infection prevalence than the feral broodstocks. Despite the high prevalence of systemic F. psychrophilum infections in many broodstock populations, the bacterium was rarely detected in their progeny during hatchery rearing. However, heavy losses associated

  10. Thermal regimes, nonnative trout, and their influences on native Bull Trout in the Upper Klamath River Basin, Oregon

    Science.gov (United States)

    Benjamin, Joseph R.; Heltzel, Jeannie; Dunham, Jason; Heck, Michael; Banish, Nolan P.

    2016-01-01

    The occurrence of fish species may be strongly influenced by a stream’s thermal regime (magnitude, frequency, variation, and timing). For instance, magnitude and frequency provide information about sublethal temperatures, variability in temperature can affect behavioral thermoregulation and bioenergetics, and timing of thermal events may cue life history events, such as spawning and migration. We explored the relationship between thermal regimes and the occurrences of native Bull Trout Salvelinus confluentus and nonnative Brook Trout Salvelinus fontinalis and Brown Trout Salmo trutta across 87 sites in the upper Klamath River basin, Oregon. Our objectives were to associate descriptors of the thermal regime with trout occurrence, predict the probability of Bull Trout occurrence, and estimate upper thermal tolerances of the trout species. We found that each species was associated with a different suite of thermal regime descriptors. Bull Trout were present at sites that were cooler, had fewer high-temperature events, had less variability, and took longer to warm. Brook Trout were also observed at cooler sites with fewer high-temperature events, but the sites were more variable and Brook Trout occurrence was not associated with a timing descriptor. In contrast, Brown Trout were present at sites that were warmer and reached higher temperatures faster, but they were not associated with frequency or variability descriptors. Among the descriptors considered, magnitude (specifically June degree-days) was the most important in predicting the probability of Bull Trout occurrence, and model predictions were strengthened by including Brook Trout occurrence. Last, all three trout species exhibited contrasting patterns of tolerating longer exposures to lower temperatures. Tolerance limits for Bull Trout were lower than those for Brook Trout and Brown Trout, with contrasts especially evident for thermal maxima. Our results confirm the value of exploring a suite of thermal

  11. Congruence between muscle activity and kinematics in a convergently derived prey-processing behavior.

    Science.gov (United States)

    Konow, Nicolai; Camp, Ariel L; Sanford, Christopher P J

    2008-08-01

    Quantification of anatomical and physiological characteristics of the function of a musculoskeletal system may yield a detailed understanding of how the organizational levels of morphology, biomechanics, kinematics, and muscle activity patterns (MAPs) influence behavioral diversity. Using separate analyses of these organizational levels in representative study taxa, we sought patterns of congruence in how organizational levels drive behavioral modulation in a novel raking prey-processing behavior found in teleosts belonging to two evolutionarily distinct lineages. Biomechanically divergent prey (elusive, robust goldfish and sedentary, malleable earthworms) were fed to knifefish, Chitala ornata (Osteoglossomorpha) and brook trout, Salvelinus fontinalis (Salmoniformes). Electromyography recorded MAPs from the hyoid protractor, jaw adductor, sternohyoideus, epaxialis, and hypaxialis musculature, while sonomicrometry sampled deep basihyal kinesis and contractile length dynamics in the basihyal protractor and retractor muscles. Syntheses of our results with recent analyses of cranial morphology and raking kinematics showed that raking in Salvelinus relies on an elongated cranial out lever, extensive cranial elevation and a curved cleithrobranchial ligament (CBL), and that both raking MAPs and kinematics remain entirely unmodulated-a highly unusual trait, particularly among feeding generalists. Chitala had a shorter CBL and a raking power stroke involving increased retraction of the elongated pectoral girdle during raking on goldfish. The raking MAP was also modulated in Chitala, involving an extensive overlap between muscle activity of the preparatory and power stroke phases, driven by shifts in hypaxial timing and recruitment of the hyoid protractor muscle. Sonomicrometry revealed that the protractor hyoideus muscle stored energy from retraction of the pectoral girdle for ca. 5-20 ms after onset of the power stroke and then hyper-extended. This mechanism of elastic

  12. Adaptive Management of Bull Trout Populations in the Lemhi Basin

    Science.gov (United States)

    Peterson, James T.; Tyre, Andrew J.; Converse, Sarah J.; Bogich, Tiffany L.; Miller, Damien; Post van der Burg, Max; Thomas, Carmen; Thompson, Ralph J.; Wood, Jeri; Brewer, Donna; Runge, Michael C.

    2011-01-01

    The bull trout Salvelinus confluentus, a stream-living salmonid distributed in drainages of the northwestern United States, is listed as threatened under the Endangered Species Act because of rangewide declines. One proposed recovery action is the reconnection of tributaries in the Lemhi Basin. Past water use policies in this core area disconnected headwater spawning sites from downstream habitat and have led to the loss of migratory life history forms. We developed an adaptive management framework to analyze which types of streams should be prioritized for reconnection under a proposed Habitat Conservation Plan. We developed a Stochastic Dynamic Program that identified optimal policies over time under four different assumptions about the nature of the migratory behavior and the effects of brook trout Salvelinus fontinalis on subpopulations of bull trout. In general, given the current state of the system and the uncertainties about the dynamics, the optimal policy would be to connect streams that are currently occupied by bull trout. We also estimated the value of information as the difference between absolute certainty about which of our four assumptions were correct, and a model averaged optimization assuming no knowledge. Overall there is little to be gained by learning about the dynamics of the system in its current state, although in other parts of the state space reducing uncertainties about the system would be very valuable. We also conducted a sensitivity analysis; the optimal decision at the current state does not change even when parameter values are changed up to 75% of the baseline values. Overall, the exercise demonstrates that it is possible to apply adaptive management principles to threatened and endangered species, but logistical and data availability constraints make detailed analyses difficult.

  13. Flavobacterium psychrophilum Infections in Salmonid Broodstock and Hatchery-Propagated Stocks of the Great Lakes Basin.

    Science.gov (United States)

    Van Vliet, Danielle; Loch, Thomas P; Faisal, Mohamed

    2015-12-01

    Bacterial coldwater disease (BCWD), caused by Flavobacterium psychrophilum, threatens wild and propagated salmonids worldwide and leads to substantial economic losses. In addition to being horizontally transmitted, F. psychrophilum can be passed from infected parents to their progeny, furthering the negative impacts of this pathogen. In Michigan, both feral and captive salmonid broodstocks are the gamete sources used in fishery propagation efforts. A 5-year study was initiated to follow the prevalence of systemic F. psychrophilum infections in feral broodstocks of four species (steelhead Oncorhynchus mykiss [potadromous Rainbow Trout]; Coho Salmon O. kisutch; Chinook Salmon O. tshawytscha; and Atlantic Salmon Salmo salar) residing in three Great Lakes watersheds. Additionally, captive broodstocks of four species (Rainbow Trout, Brown Trout Salmo trutta, Lake Trout Salvelinus namaycush, and Brook Trout Salvelinus fontinalis) maintained at two facilities were assessed for the presence of F. psychrophilum. The resultant offspring from each broodstock population were sampled for F. psychrophilum infections multiple times throughout hatchery residency. Using selective flavobacterial culture and PCR confirmation, F. psychrophilum was detected in all broodstocks except the captive Lake Trout and Brook Trout. Logistic regression analysis demonstrated that among the infected feral broodstocks, Chinook Salmon from the Lake Michigan watershed had the highest prevalence of systemic F. psychrophilum infection (mean = 63.2%). Among the captive broodstocks, the Gilchrist Creek strain of Brown Trout had the highest infection prevalence (mean = 5%). Collectively, the captive broodstocks were found to have significantly lower infection prevalence than the feral broodstocks. Despite the high prevalence of systemic F. psychrophilum infections in many broodstock populations, the bacterium was rarely detected in their progeny during hatchery rearing. However, heavy losses associated

  14. The effects of inbreeding on sperm quality traits in captive‐bred lake trout, Salvelinus namaycush (Walbaum, 1972)

    DEFF Research Database (Denmark)

    Johnson, K.; Butts, I. A. E.; Smith, J. L.;

    2015-01-01

    The effects of inbreeding in both captive and wild‐caught species and populations have been reported to affect a wide variety of life history traits. Recently, the effects of inbreeding on reproductive traits such as sperm quality have become a subject of particular interest for conservation...

  15. Biomagnification of mercury through lake trout (Salvelinus namaycush) food webs of lakes with different physical, chemical and biological characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Kidd, Karen A., E-mail: kiddk@unbsj.ca [Canadian Rivers Institute and Biology Department, University of New Brunswick, Saint John, NB, Canada E2L 4L5 (Canada); Muir, Derek C.G., E-mail: derek.muir@ec.gc.ca [Aquatic Contaminants Research Division, Environment Canada, Burlington, ON, Canada L7R 4A6 (Canada); Evans, Marlene S., E-mail: marlene.evans@ec.gc.ca [Aquatic Contaminants Research Division, Environment Canada, Saskatoon, SK, Canada S7N 3H5 (Canada); Wang, Xioawa, E-mail: xiaowa.wang@ec.gc.ca [Aquatic Contaminants Research Division, Environment Canada, Burlington, ON, Canada L7R 4A6 (Canada); Whittle, Mike [Aquatic Contaminants Research Division, Environment Canada, Burlington, ON, Canada L7R 4A6 (Canada); Swanson, Heidi K., E-mail: heidikswanson@yahoo.ca [Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada T6G 2E9 (Canada); Johnston, Tom, E-mail: tjohnston@laurentian.ca [Cooperative Freshwater Ecology Unit, Ontario Ministry of Natural Resources, and Biology Department, Laurentian University, Sudbury, ON, Canada P3E 2C6 (Canada); Guildford, Stephanie, E-mail: sguildfo@d.umn.edu [Department of Biology and Large Lakes Observatory, University of Minnesota Duluth, 2205 5th St., Duluth, MN, 55812 (United States)

    2012-11-01

    Mercury (Hg) biomagnification in aquatic ecosystems remains a concern because this pollutant is known to affect the health of fish-eating wildlife and humans, and the fish themselves. The 'rate' of mercury biomagnification is being assessed more frequently using stable nitrogen isotope ratios ({delta}{sup 15}N), a measure of relative trophic position of biota within a food web. Within food webs and across diverse systems, log-transformed Hg concentrations are significantly and positively related to {delta}{sup 15}N and the slopes of these models vary from one study to another for reasons that are not yet understood. Here we compared the rates of Hg biomagnification in 14 lake trout lakes from three provinces in Canada to understand whether any characteristics of the ecosystems explained this among-system variability. Several fish species, zooplankton and benthic invertebrates were collected from these lakes and analyzed for total Hg (fish only), methyl Hg (invertebrates) and stable isotopes ({delta}{sup 15}N; {delta}{sup 13}C to assess energy sources). Mercury biomagnification rates varied significantly across systems and were higher for food webs of larger (surface area), higher nutrient lakes. However, the slopes were not predictive of among-lake differences in Hg in the lake trout. Results indicate that among-system differences in the rates of Hg biomagnification seen in the literature may be due, in part, to differences in ecosystem characteristics although the mechanisms for this variability are not yet understood. -- Highlights: Black-Right-Pointing-Pointer Mercury biomagnifies through aquatic food webs to toxic levels in top predator fishes. Black-Right-Pointing-Pointer Among-system differences in mercury transfer through food webs occur but have not been explained. Black-Right-Pointing-Pointer Diverse lakes supporting lake trout were compared to understand the ecosystem processes that affect mercury biomagnification. Black-Right-Pointing-Pointer Higher biomagnification of mercury was found in larger, higher nutrient lakes. Black-Right-Pointing-Pointer Results show that the food web processing of mercury is related to ecosystem properties.

  16. Identification of lake trout Salvelinus namaycush spawning habitat in northern Lake Huron using high-resolution satellite imagery

    Science.gov (United States)

    Grimm, Amanda G.; Brooks, Colin N.; Binder, Thomas R.; Riley, Stephen C.; Farha, Steve A.; Shuchman, Robert A.; Krueger, Charles C.

    2016-01-01

    The availability and quality of spawning habitat may limit lake trout recovery in the Great Lakes, but little is known about the location and characteristics of current spawning habitats. Current methods used to identify lake trout spawning locations are time- and labor-intensive and spatially limited. Due to the observation that some lake trout spawning sites are relatively clean of overlaying algae compared to areas not used for spawning, we suspected that spawning sites could be identified using satellite imagery. Satellite imagery collected just before and after the spawning season in 2013 was used to assess whether lake trout spawning habitat could be identified based on its spectral characteristics. Results indicated that Pléiades high-resolution multispectral satellite imagery can be successfully used to estimate algal coverage of substrates and temporal changes in algal coverage, and that models developed from processed imagery can be used to identify potential lake trout spawning sites based on comparison of sites where lake trout eggs were and were not observed after spawning. Satellite imagery is a potential new tool for identifying lake trout spawning habitat at large scales in shallow nearshore areas of the Great Lakes.

  17. Evolution and origin of sympatric shallow-water morphotypes of Lake Trout, Salvelinus namaycush, in Canada's Great Bear Lake

    OpenAIRE

    Harris, L N; Chavarie, L; Bajno, R; Howland, K L; Wiley, S H; Tonn, W M; Taylor, E B

    2014-01-01

    Range expansion in north-temperate fishes subsequent to the retreat of the Wisconsinan glaciers has resulted in the rapid colonization of previously unexploited, heterogeneous habitats and, in many situations, secondary contact among conspecific lineages that were once previously isolated. Such ecological opportunity coupled with reduced competition likely promoted morphological and genetic differentiation within and among post-glacial fish populations. Discrete morphological forms existing i...

  18. Biomagnification of mercury through lake trout (Salvelinus namaycush) food webs of lakes with different physical, chemical and biological characteristics.

    Science.gov (United States)

    Kidd, Karen A; Muir, Derek C G; Evans, Marlene S; Wang, Xioawa; Whittle, Mike; Swanson, Heidi K; Johnston, Tom; Guildford, Stephanie

    2012-11-01

    Mercury (Hg) biomagnification in aquatic ecosystems remains a concern because this pollutant is known to affect the health of fish-eating wildlife and humans, and the fish themselves. The "rate" of mercury biomagnification is being assessed more frequently using stable nitrogen isotope ratios (δ(15)N), a measure of relative trophic position of biota within a food web. Within food webs and across diverse systems, log-transformed Hg concentrations are significantly and positively related to δ(15)N and the slopes of these models vary from one study to another for reasons that are not yet understood. Here we compared the rates of Hg biomagnification in 14 lake trout lakes from three provinces in Canada to understand whether any characteristics of the ecosystems explained this among-system variability. Several fish species, zooplankton and benthic invertebrates were collected from these lakes and analyzed for total Hg (fish only), methyl Hg (invertebrates) and stable isotopes (δ(15)N; δ(13)C to assess energy sources). Mercury biomagnification rates varied significantly across systems and were higher for food webs of larger (surface area), higher nutrient lakes. However, the slopes were not predictive of among-lake differences in Hg in the lake trout. Results indicate that among-system differences in the rates of Hg biomagnification seen in the literature may be due, in part, to differences in ecosystem characteristics although the mechanisms for this variability are not yet understood. PMID:22982939

  19. Biomagnification of mercury through lake trout (Salvelinus namaycush) food webs of lakes with different physical, chemical and biological characteristics

    International Nuclear Information System (INIS)

    Mercury (Hg) biomagnification in aquatic ecosystems remains a concern because this pollutant is known to affect the health of fish-eating wildlife and humans, and the fish themselves. The “rate” of mercury biomagnification is being assessed more frequently using stable nitrogen isotope ratios (δ15N), a measure of relative trophic position of biota within a food web. Within food webs and across diverse systems, log-transformed Hg concentrations are significantly and positively related to δ15N and the slopes of these models vary from one study to another for reasons that are not yet understood. Here we compared the rates of Hg biomagnification in 14 lake trout lakes from three provinces in Canada to understand whether any characteristics of the ecosystems explained this among-system variability. Several fish species, zooplankton and benthic invertebrates were collected from these lakes and analyzed for total Hg (fish only), methyl Hg (invertebrates) and stable isotopes (δ15N; δ13C to assess energy sources). Mercury biomagnification rates varied significantly across systems and were higher for food webs of larger (surface area), higher nutrient lakes. However, the slopes were not predictive of among-lake differences in Hg in the lake trout. Results indicate that among-system differences in the rates of Hg biomagnification seen in the literature may be due, in part, to differences in ecosystem characteristics although the mechanisms for this variability are not yet understood. -- Highlights: ► Mercury biomagnifies through aquatic food webs to toxic levels in top predator fishes. ► Among-system differences in mercury transfer through food webs occur but have not been explained. ► Diverse lakes supporting lake trout were compared to understand the ecosystem processes that affect mercury biomagnification. ► Higher biomagnification of mercury was found in larger, higher nutrient lakes. ► Results show that the food web processing of mercury is related to ecosystem properties.

  20. Are brook trout streams in Western Virginia and Shenandoah National Park recovering from acidification?

    Energy Technology Data Exchange (ETDEWEB)

    James R. Webb; Bernard J. Cosby; Frank A. Deviney, Jr.; James N. Galloway; Suzanne W. Maben; Arthur J. Bulger [University of Virginia, Charlottesville, VA (United States). Department of Environmental Sciences

    2004-08-01

    Streamwater composition data obtained through periodic sampling of streams that support brook trout (Salvelinus fontinalis) in the mountains of western Virginia were examined for evidence of recovery from acidification during the 1988-2001 period. Measurements of sulfate deposition in precipitation indicate that sulfate deposition in the region declined approximately 40% between 1985 and 2000. While no significant regional trends in acid-base constituents were observed for the set (n = 65) of western Virginia study streams, significant regional trends were observed for a subset (n = 14) of streams in Shenandoah National Park (SNP). For the subset of SNP streams, the median increase in acid-neutralizing capacity (ANC) was 0.168 {mu} equiv L{sup -1} year{sup -1} and the median decrease in sulfate concentration was -0.229 {mu}equiv L{sup -1} year{sup -1}. Although these trends are consistent with recovery from acidification, the degree of apparent recovery is small compared to estimates of historic acidification in SNP streams and much less than observed in other, more northern regions in the United States. Correlation between sulfate concentration trends and current sulfate concentrations in streamwater suggests that recovery from stream acidification in the western Virginia region is determined by sulfur retention processes in watershed soils. A transient increase in nitrate concentrations that occurred among some western Virginia streams following forest defoliation by the gypsy moth (Lymantria dispar) complicates interpretation of the observed patterns of change in acid-base status. 28 refs., 6 figs., 1 tab.

  1. Maintenance of phenotypic variation: Repeatability, heritability and size-dependent processes in a wild brook trout population

    Science.gov (United States)

    Letcher, B.H.; Coombs, J.A.; Nislow, K.H.

    2011-01-01

    Phenotypic variation in body size can result from within-cohort variation in birth dates, among-individual growth variation and size-selective processes. We explore the relative effects of these processes on the maintenance of wide observed body size variation in stream-dwelling brook trout (Salvelinus fontinalis). Based on the analyses of multiple recaptures of individual fish, it appears that size distributions are largely determined by the maintenance of early size variation. We found no evidence for size-dependent compensatory growth (which would reduce size variation) and found no indication that size-dependent survival substantially influenced body size distributions. Depensatory growth (faster growth by larger individuals) reinforced early size variation, but was relatively strong only during the first sampling interval (age-0, fall). Maternal decisions on the timing and location of spawning could have a major influence on early, and as our results suggest, later (>age-0) size distributions. If this is the case, our estimates of heritability of body size (body length=0.25) will be dominated by processes that generate and maintain early size differences. As a result, evolutionary responses to environmental change that are mediated by body size may be largely expressed via changes in the timing and location of reproduction. Published 2011. This article is a US Government work and is in the public domain in the USA.

  2. Heritability of morphology in brook trout with variable life histories.

    Directory of Open Access Journals (Sweden)

    Anna Varian

    Full Text Available Distinct morphological variation is often associated with variation in life histories within and among populations of both plants and animals. In this study, we examined the heritability of morphology in three hatchery strains of brook trout (Salvelinus fontinalis, which were historically or are currently used for stocking and supplementation of both migratory and resident ecotypes in the upper Great Lakes region. In a common garden experiment, significant variation in body morphology was observed within and across populations sampled at three time periods. The most notable differences among strains were differences in dorso-ventral body depth and the shape of the caudal peduncle, with some differences in the anterior-posterior placement of the dorsal and ventral fins. Variation with and among 70 half-sib families indicates that heritabilities of morphology and body size were significant at most developmental time points both within and across strains. Heritabilities for morphological characters within strains ranged from 0 to 0.95 across time points. Significant within-strain heritabilities for length ranged from 0 to 0.93 across time points and for weight ranged from 0 to 0.88. Significant additive genetic variation exists within and across hatchery brook trout strains for morphology and size, indicating that these traits are capable of responding to natural or artificial selection.

  3. Species replacement by a nonnative salmonid alters ecosystem function by reducing prey subsidies that support riparian spiders.

    Science.gov (United States)

    Benjamin, Joseph R; Fausch, Kurt D; Baxter, Colden V

    2011-10-01

    Replacement of a native species by a nonnative can have strong effects on ecosystem function, such as altering nutrient cycling or disturbance frequency. Replacements may cause shifts in ecosystem function because nonnatives establish at different biomass, or because they differ from native species in traits like foraging behavior. However, no studies have compared effects of wholesale replacement of a native by a nonnative species on subsidies that support consumers in adjacent habitats, nor quantified the magnitude of these effects. We examined whether streams invaded by nonnative brook trout (Salvelinus fontinalis) in two regions of the Rocky Mountains, USA, produced fewer emerging adult aquatic insects compared to paired streams with native cutthroat trout (Oncorhynchus clarkii), and whether riparian spiders that depend on these prey were less abundant along streams with lower total insect emergence. As predicted, emergence density was 36% lower from streams with the nonnative fish. Biomass of brook trout was higher than the cutthroat trout they replaced, but even after accounting for this difference, emergence was 24% lower from brook trout streams. More riparian spiders were counted along streams with greater total emergence across the water surface. Based on these results, we predicted that brook trout replacement would result in 6-20% fewer spiders in the two regions. When brook trout replace cutthroat trout, they reduce cross-habitat resource subsidies and alter ecosystem function in stream-riparian food webs, not only owing to increased biomass but also because traits apparently differ from native cutthroat trout.

  4. Movement patterns of Brook Trout in a restored coastal stream system in southern Massachusetts

    Science.gov (United States)

    Snook, Erin L.; Letcher, Benjamin H.; Dubreuil, Todd L.; Zydlewski, Joseph; O'Donnell, Matthew J.; Whiteley, Andrew R.; Hurley, Stephen T.; Danylchuk, Andy J.

    2016-01-01

    Coastal Brook Trout (Salvelinus fontinalis) populations are found from northern Canada to New England. The extent of anadromy generally decreases with latitude, but the ecology and movements of more southern populations are poorly understood. We conducted a 33-month acoustic telemetry study of Brook Trout in Red Brook, MA, and adjacent Buttermilk Bay (marine system) using 16 fixed acoustic receivers and surgically implanting acoustic transmitters in 84 individuals. Tagged Brook Trout used the stream, estuary (50% of individuals) and bay (10% of individuals). Movements into full sea water were brief when occurring. GAMM models revealed that transitions between habitat areas occurred most often in spring and fall. Environmental data suggest that use of the saline environment is limited by summer temperatures in the bay. Movements may also be related to moon phase. Compared to more northern coastal populations of Brook Trout, the Red Brook population appears to be less anadromous overall, yet the estuarine segment of the system may have considerable ecological importance as a food resource.

  5. Water striders (family Gerridae): mercury sentinels in small freshwater ecosystems

    International Nuclear Information System (INIS)

    To circumvent some of the previous limitations associated with contaminant-monitoring programs, we tested the suitability of the water strider (Hemiptera: Gerridae) as a mercury sentinel by comparing total mercury concentrations in water striders and brook trout (Salvelinus fontinalis) from a variety of stream sites in New Brunswick, Canada. There was a strong association between the two variables across sites (r2 = 0.81, P < 0.001) in systems where both atmospheric deposition and a point source (an abandoned gold mine) were likely contributing to ambient mercury levels. In a small stream draining the gold mine tailings pile, water striders had mercury concentrations an order of magnitude higher than those from reference locations. Temporal variation at three southern New Brunswick stream sites was non-significant. These results suggest that water strider mercury levels accurately quantify food chain entry of the element. The use of sentinel species holds great potential for expanding contaminant-monitoring programs. - Water striders accurately reflect the entry of mercury in food chains of small freshwater systems

  6. Growth rate differences between resident native brook trout and non-native brown trout

    Science.gov (United States)

    Carlson, S.M.; Hendry, A.P.; Letcher, B.H.

    2007-01-01

    Between species and across season variation in growth was examined by tagging and recapturing individual brook trout Salvelinus fontinalis and brown trout Salmo trutta across seasons in a small stream (West Brook, Massachusetts, U.S.A.). Detailed information on body size and growth are presented to (1) test whether the two species differed in growth within seasons and (2) characterize the seasonal growth patterns for two age classes of each species. Growth differed between species in nearly half of the season- and age-specific comparisons. When growth differed, non-native brown trout grew faster than native brook trout in all but one comparison. Moreover, species differences were most pronounced when overall growth was high during the spring and early summer. These growth differences resulted in size asymmetries that were sustained over the duration of the study. A literature survey also indicated that non-native salmonids typically grow faster than native salmonids when the two occur in sympatry. Taken together, these results suggest that differences in growth are not uncommon for coexisting native and non-native salmonids. ?? 2007 The Authors.

  7. Water quality trends in the Blackwater River watershed, West Virginia

    Science.gov (United States)

    Smith, Jessica; Welsh, Stuart; Anderson, James T.; Fortney, Ronald H.

    2015-01-01

    An understanding of historic and current water quality is needed to manage and improve aquatic communities within the Blackwater River watershed, WV. The Blackwater River, which historically offered an excellent Salvelinus fontinalis (Brook Trout) fishery, has been affected by logging, coal mining, use of off-road vehicles, and land development. Using information-theoretic methods, we examined trends in water quality at 12 sites in the watershed for the 14 years of 1980–1993. Except for Beaver Creek, downward trends in acidity and upward trends in alkalinity, conductivity, and hardness were consistent with decreases in hydrogen ion concentration. Water-quality trends for Beaver Creek were inconsistent with the other sites and reflect ongoing coal-mining influences. Dissolved oxygen trended downward, possibly due to natural conditions, but remained above thresholds that would be detrimental to aquatic life. Water quality changed only slightly within the watershed from 1980–1993, possibly reflecting few changes in development and land uses during this time. These data serve as a baseline for future water-quality studies and may help to inform management planning.

  8. Species replacement by a nonnative salmonid alters ecosystem function by reducing prey subsidies that support riparian spiders.

    Science.gov (United States)

    Benjamin, Joseph R; Fausch, Kurt D; Baxter, Colden V

    2011-10-01

    Replacement of a native species by a nonnative can have strong effects on ecosystem function, such as altering nutrient cycling or disturbance frequency. Replacements may cause shifts in ecosystem function because nonnatives establish at different biomass, or because they differ from native species in traits like foraging behavior. However, no studies have compared effects of wholesale replacement of a native by a nonnative species on subsidies that support consumers in adjacent habitats, nor quantified the magnitude of these effects. We examined whether streams invaded by nonnative brook trout (Salvelinus fontinalis) in two regions of the Rocky Mountains, USA, produced fewer emerging adult aquatic insects compared to paired streams with native cutthroat trout (Oncorhynchus clarkii), and whether riparian spiders that depend on these prey were less abundant along streams with lower total insect emergence. As predicted, emergence density was 36% lower from streams with the nonnative fish. Biomass of brook trout was higher than the cutthroat trout they replaced, but even after accounting for this difference, emergence was 24% lower from brook trout streams. More riparian spiders were counted along streams with greater total emergence across the water surface. Based on these results, we predicted that brook trout replacement would result in 6-20% fewer spiders in the two regions. When brook trout replace cutthroat trout, they reduce cross-habitat resource subsidies and alter ecosystem function in stream-riparian food webs, not only owing to increased biomass but also because traits apparently differ from native cutthroat trout. PMID:21688160

  9. Characterizing the thermal suitability of instream habitat for salmonids: A cautionary example from the Rocky Mountains

    Science.gov (United States)

    Al-Chokhachy, Robert K.; Wegner, Seth J.; Isaak, Daniel J.; Kershner, Jeffrey L.

    2013-01-01

    Understanding a species’ thermal niche is becoming increasingly important for management and conservation within the context of global climate change, yet there have been surprisingly few efforts to compare assessments of a species’ thermal niche across methods. To address this uncertainty, we evaluated the differences in model performance and interpretations of a species’ thermal niche when using different measures of stream temperature and surrogates for stream temperature. Specifically, we used a logistic regression modeling framework with three different indicators of stream thermal conditions (elevation, air temperature, and stream temperature) referenced to a common set of Brook Trout Salvelinus fontinalis distribution data from the Boise River basin, Idaho. We hypothesized that stream temperature predictions that were contemporaneous with fish distribution data would have stronger predictive performance than composite measures of stream temperature or any surrogates for stream temperature. Across the different indicators of thermal conditions, the highest measure of accuracy was found for the model based on stream temperature predictions that were contemporaneous with fish distribution data (percent correctly classified = 71%). We found considerable differences in inferences across models, with up to 43% disagreement in the amount of stream habitat that was predicted to be suitable. The differences in performance between models support the growing efforts in many areas to develop accurate stream temperature models for investigations of species’ thermal niches.

  10. Fish dispersal in fragmented landscapes: a modeling framework for quantifying the permeability of structural barriers.

    Science.gov (United States)

    Pépino, Marc; Rodríguez, Marco A; Magnan, Pierre

    2012-07-01

    Dispersal is a key determinant of the spatial distribution and abundance of populations, but human-made fragmentation can create barriers that hinder dispersal and reduce population viability. This study presents a modeling framework based on dispersal kernels (modified Laplace distributions) that describe stream fish dispersal in the presence of obstacles to passage. We used mark-recapture trials to quantify summer dispersal of brook trout (Salvelinus fontinalis) in four streams crossed by a highway. The analysis identified population heterogeneity in dispersal behavior, as revealed by the presence of a dominant sedentary component (48-72% of all individuals) characterized by short mean dispersal distance (dispersal distance (56-1086 m). We did not detect evidence of barrier effects on dispersal through highway crossings. Simulation of various plausible scenarios indicated that detectability of barrier effects was strongly dependent on features of sampling design, such as spatial configuration of the sampling area, barrier extent, and sample size. The proposed modeling framework extends conventional dispersal kernels by incorporating structural barriers. A major strength of the approach is that ecological process (dispersal model) and sampling design (observation model) are incorporated simultaneously into the analysis. This feature can facilitate the use of prior knowledge to improve sampling efficiency of mark-recapture trials in movement studies. Model-based estimation of barrier permeability and its associated uncertainty provides a rigorous approach for quantifying the effect of barriers on stream fish dispersal and assessing population dynamics of stream fish in fragmented landscapes.

  11. Genetic identity of brook trout in Lake Superior south shore streams: Potential for genetic monitoring of stocking and rehabilitation efforts

    Science.gov (United States)

    Sloss, Brian L.; Jennings, Martin J.; Franckowiak, R.; Pratt, D.M.

    2008-01-01

    Rehabilitation of migratory ('coaster') brook trout Salvelinus fontinalis along Lake Superior's south shore is a topic of high interest among resource stakeholders and management agencies. Proposed strategies for rehabilitation of this brook trout life history variant in Wisconsin include supplemental stocking, watershed management, habitat rehabilitation, harvest regulations, or a combination thereof. In an effort to evaluate the success of coaster brook trout rehabilitation efforts, we collected genetic data from four populations of interest (Whittlesey Creek, Bois Brule River, Bark River, and Graveyard Creek) and the hatchery sources used in the Whittlesey Creek supplementation experiment. We characterized the genetic diversity of 30 individuals from each of four populations using 13 microsatellite DNA loci. Levels of genetic variation were consistent with those in similar studies conducted throughout the basin. Significant genetic variation among the populations was observed, enabling adequate population delineation through assignment tests. Overall, 208 of the 211 sampled fish (98.6%) were correctly assigned to their population of origin. Simulated F1 hybrids between two hatchery strains and the Whittlesey Creek population were identifiable in the majority of attempts (90.5-100% accuracy with 0-2.5% error). The genetic markers and analytical techniques described provide the ability to monitor the concurrent coaster brook trout rehabilitation efforts along Wisconsin's Lake Superior south shore, including the detection of hybridization between hatchery and native populations. ?? Copyright by the American Fisheries Society 2008.

  12. Brook trout passage performance through culverts

    Science.gov (United States)

    Goerig, Elsa; Castro-Santos, Theodore R.; Bergeron, Normand

    2016-01-01

    Culverts can restrict access to habitat for stream-dwelling fishes. We used passive integrated transponder telemetry to quantify passage performance of >1000 wild brook trout (Salvelinus fontinalis) attempting to pass 13 culverts in Quebec under a range of hydraulic and environmental conditions. Several variables influenced passage success, including complex interactions between physiology and behavior, hydraulics, and structural characteristics. The probability of successful passage was greater through corrugated metal culverts than through smooth ones, particularly among smaller fish. Trout were also more likely to pass at warmer temperatures, but this effect diminished above 15 °C. Passage was impeded at higher flows, through culverts with steep slopes, and those with deep downstream pools. This study provides insight on factors influencing brook trout capacity to pass culverts as well as a model to estimate passage success under various conditions, with an improved resolution and accuracy over existing approaches. It also presents methods that could be used to investigate passage success of other species, with implications for connectivity of the riverscape.

  13. Conservation genetics of Lake Superior brook trout: Issues, questions, and directions

    Science.gov (United States)

    Wilson, C.C.; Stott, W.; Miller, L.; D'Amelio, S.; Jennings, Martin J.; Cooper, A.M.

    2008-01-01

    Parallel efforts by several genetic research groups have tackled common themes relating to management concerns about and recent rehabilitation opportunities for coaster brook trout Salvelinus fontinalis in Lake Superior. The questions that have been addressed include the evolutionary and genetic status of coaster brook trout, the degree of relatedness among coaster populations and their relationship to riverine tributary brook trout populations, and the role and effectiveness of stocking in maintaining and restoring coasters to Lake Superior. Congruent genetic results indicate that coasters are an ecotype (life history variant) rather than an evolutionarily significant unit or genetically distinct strain. Regional structure exists among brook trout stocks, coasters being produced from local populations. Introgression of hatchery genes into wild populations appears to vary regionally and may relate to local population size, habitat integrity, and anthropogenic pressures. Tracking the genetic diversity and integrity associated with captive breeding programs is helping to ensure that the fish used for stocking are representative of their source populations and appropriate for rehabilitation efforts. Comparative analysis of shared samples among collaborating laboratories is enabling standardization of genotype scoring and interpretation as well as the development of a common toolkit for assessing genetic structure and diversity. Incorporation of genetic data into rehabilitation projects will facilitate monitoring efforts and subsequent adaptive management. Together, these multifaceted efforts provide comprehensive insights into the biology of coaster brook trout and enhance restoration options. ?? Copyright by the American Fisheries Society 2008.

  14. Episodic acidification of small streams in the northeastern united states: Effects on fish populations

    Science.gov (United States)

    Baker, J.P.; Van Sickle, J.; Gagen, C.J.; DeWalle, David R.; Sharpe, W.E.; Carline, R.F.; Baldigo, Barry P.; Murdoch, Peter S.; Bath, D.W.; Kretser, W.A.; Simonin, H.A.; Wigington, P.J.

    1996-01-01

    As part of the Episodic Response Project (ERP), we studied the effects of episodic acidification on fish in 13 small streams in the northeastern United States: four streams in the Adirondack region of New York, four streams in the Catskills, New York, and five streams in the northern Appalachian Plateau, Pennsylvania. In situ bioassays with brook trout (Salvelinus fontinalis) and a forage fish species (blacknose dace (Rhinichthys atratulus], mottled sculpin (Cottus bairdi), or slimy sculpin (Cottus cognatus), depending on the region) measured direct toxicity. Movements of individual brook trout, in relation to stream chemistry, were monitored using radiotelemetry. Electrofishing surveys assessed fish community status and the density and biomass of brook trout in each stream. During low flow, all streams except one had chemical conditions considered suitable for the survival and reproduction of most fish species (median pH 6.0-7.2 during low flow; inorganic Al 100-200 ??g/L. We conclude that episodic acidification can have long-term effects on fish communities in small streams.

  15. Stable isotope evaluation of population- and individual-level diet variability in a large, oligotrophic lake with non-native lake trout

    Science.gov (United States)

    Ng, Elizabeth L.; Fredericks, Jim P.; Quist, Michael C.

    2016-01-01

    Non-native piscivores can alter food web dynamics; therefore, evaluating interspecific relationships is vital for conservation and management of ecosystems with introduced fishes. Priest Lake, Idaho, supports a number of introduced species, including lake troutSalvelinus namaycush, brook trout S. fontinalis and opossum shrimp Mysis diluviana. In this study, we used stable isotopes (δ13C and δ15N) to describe the food web structure of Priest Lake and to test hypotheses about apparent patterns in lake trout growth. We found that isotopic niches of species using pelagic-origin carbon did not overlap with those using more littoral-origin carbon. Species using more littoral-origin carbon, such as brook trout and westslope cutthroat trout Oncorhynchus clarki lewisi, exhibited a high degree of isotopic niche overlap and high intrapopulation variability in resource use. Although we hypothesised that lake trout would experience an ontogenetic diet shift, no such patterns were apparent in isotopic signatures. Lake trout growth rates were not associated with patterns in δ15N, indicating that variation in adult body composition may not be related to adult diet. Understanding trophic relationships at both the individual and species levels provides a more complete understanding of food webs altered by non-native species.

  16. Aquatic and terrestrial organic matter in the diet of stream consumers: implications for mercury bioaccumulation.

    Science.gov (United States)

    Jardine, Timothy D; Kidd, Karen A; Rasmussen, Joseph B

    2012-04-01

    The relative contribution of aquatic vs. terrestrial organic matter to the diet of consumers in fluvial environments and its effects on bioaccumulation of contaminants such as mercury (Hg) remain poorly understood. We used stable isotopes of carbon and nitrogen in a gradient approach (consumer isotope ratio vs. periphyton isotope ratio) across temperate streams that range in their pH to assess consumer reliance on aquatic (periphyton) vs. terrestrial (riparian vegetation) organic matter, and whether Hg concentrations in fish and their prey were related to these energy sources. Taxa varied in their use of the two sources, with grazing mayflies (Heptageniidae), predatory stoneflies (Perlidae), one species of water strider (Metrobates hesperius), and the fish blacknose dace (Rhinichthys atratulus) showing strong connections to aquatic sources, while Aquarius remigis water striders and brook trout (Salvelinus fontinalis) showed a weak link to in-stream production. The aquatic food source for consumers, periphyton, had higher Hg concentrations in low-pH waters, and pH was a much better predictor of Hg in predatory invertebrates that relied mainly on this food source vs. those that used terrestrial C. These findings suggest that stream biota relying mainly on dietary inputs from the riparian zone will be partially insulated from the effects of water chemistry on Hg availability. This has implications for the development of a whole-system understanding of nutrient and material cycling in streams, the choice of taxa in contaminant monitoring studies, and in understanding the fate of Hg in stream food webs. PMID:22645815

  17. Community structure influences species' abundance along environmental gradients.

    Science.gov (United States)

    Eloranta, Antti P; Helland, Ingeborg P; Sandlund, Odd T; Hesthagen, Trygve; Ugedal, Ola; Finstad, Anders G

    2016-01-01

    Species' response to abiotic environmental variation can be influenced by local community structure and interspecific interactions, particularly in restricted habitats such as islands and lakes. In temperate lakes, future increase in water temperature and run-off of terrestrial (allochthonous) dissolved organic carbon (DOC) are predicted to alter community composition and the overall ecosystem productivity. However, little is known about how the present community structure and abiotic environmental variation interact to affect the abundance of native fish populations. We used a space-for-time approach to study how local community structure interact with lake morphometric and climatic characteristics (i.e. temperature and catchment productivity) to affect brown trout (Salmo trutta L.) yield in 283 Norwegian lakes located in different biogeographical regions. Brown trout yield (based on data from standardized survey gill net fishing; g 100 m(-2) gill net night(-1)) was generally lower in lakes where other fish species were present than in lakes with brown trout only. The yield showed an overall negative relationship with increasing temperature and a positive relationship with lake shoreline complexity. Brown trout yield was also negatively correlated with DOC load (measured using Normalized Difference Vegetation Index as a proxy) and lake size and depth (measured using terrain slope as a proxy), but only in lakes where other fish species were present. The observed negative response of brown trout yield to increasing DOC load and proportion of the pelagic open-water area is likely due to restricted (littoral) niche availability and competitive dominance of more pelagic fishes such as Arctic charr (Salvelinus alpinus (L.)). Our study highlights that, through competitive interactions, the local community structure can influence the response of a species' abundance to variation in abiotic conditions. Changes in biomass and niche use of top predators (such as the brown

  18. Virulence of Renibacterium salmoninarum to salmonids

    Science.gov (United States)

    Starliper, C.E.; Smith, D.R.; Shatzer, T.

    1997-01-01

    Virulence of Renibacterium salmoninarum isolates representing five origins was evaluated in eight salmonid hosts; four origins were of Lake Michigan and the fifth was of the Pacific Northwest. The species type strain, ATCC (American Type Culture Collection) 33209, was also included. Each isolate was grown in a kidney disease medium (KDM2) supplemented with 1 % ATCC 33209 culture metabolite; serial 10-fold dilutions were prepared, and groups of fish were challenged by intraperitoneal injection with 0.1 mL of each dilution. A 70-d observation period followed, and bacterial kidney disease (BKD) was diagnosed by the fluorescent antibody technique. Virulence of isolates was quantified as a dose lethal to 50% of fish (LD50) for each host–isolate challenge. In the first set of experiments, 23 isolates were used to challenge groups of brook trout Salvelinus fontinalis. The mean LD50 was 1.087 x 106 colony-forming units per milliliter (cfu/mL; SD = 2.022 x 106), and the LD50 values ranged from 8.457 x 106 to 2.227 x 104 cfu/mL. Analysis of variance to evaluate the effect of isolate origin on virulence in brook trout revealed no significant difference (F = 1.502; P = 0.243). Susceptibilities of the other salmonid hosts were evaluated by challenge with six isolates of R. salmoninarum representing each origin and the species type strain. For many of the host–isolate challenge combinations, time to death was highly dependent on the dilution (number of bacteria) injected. In general, the isolates MCO4M, B26, and A34 (all of Lake Michigan origin) tended to be more virulent. Also, LD50 values were dispersed throughout a wider range among the more susceptible hosts. Lake trout Salvelinus namaycush, rainbow trout Oncorhynchus mykiss, and brook trout were relatively resistant to challenge with the strains, whereas coho salmon O. kisutch, domestic Atlantic salmon Saltno salar, and chinook salmon O. tshawytscha were relatively susceptible. Another challenge evaluated the effect of

  19. Kalispel Non-Native Fish Suppression Project 2007 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Wingert, Michele; Andersen, Todd [Kalispel Natural Resource Department

    2008-11-18

    Non-native salmonids are impacting native salmonid populations throughout the Pend Oreille Subbasin. Competition, hybridization, and predation by non-native fish have been identified as primary factors in the decline of some native bull trout (Salvelinus confluentus) and westslope cutthroat trout (Oncorhynchus clarki lewisi) populations. In 2007, the Kalispel Natural Resource Department (KNRD) initiated the Kalispel Nonnative Fish Suppression Project. The goal of this project is to implement actions to suppress or eradicate non-native fish in areas where native populations are declining or have been extirpated. These projects have previously been identified as critical to recovering native bull trout and westslope cutthroat trout (WCT). Lower Graham Creek was invaded by non-native rainbow (Oncorhynchus mykiss) and brook trout (Salvelinus fontinalis) after a small dam failed in 1991. By 2003, no genetically pure WCT remained in the lower 700 m of Graham Creek. Further invasion upstream is currently precluded by a relatively short section of steep, cascade-pool stepped channel section that will likely be breached in the near future. In 2008, a fish management structure (barrier) was constructed at the mouth of Graham Creek to preclude further invasion of non-native fish into Graham Creek. The construction of the barrier was preceded by intensive electrofishing in the lower 700 m to remove and relocate all captured fish. Westslope cutthroat trout have recently been extirpated in Cee Cee Ah Creek due to displacement by brook trout. We propose treating Cee Cee Ah Creek with a piscicide to eradicate brook trout. Once eradication is complete, cutthroat trout will be translocated from nearby watersheds. In 2004, the Washington Department of Fish and Wildlife (WDFW) proposed an antimycin treatment within the subbasin; the project encountered significant public opposition and was eventually abandoned. However, over the course of planning this 2004 project, little public

  20. Do low-mercury terrestrial resources subsidize low-mercury growth of stream fish? Differences between species along a productivity gradient.

    Directory of Open Access Journals (Sweden)

    Darren M Ward

    Full Text Available Low productivity in aquatic ecosystems is associated with reduced individual growth of fish and increased concentrations of methylmercury (MeHg in fish and their prey. However, many stream-dwelling fish species can use terrestrially-derived food resources, potentially subsidizing growth at low-productivity sites, and, because terrestrial resources have lower MeHg concentrations than aquatic resources, preventing an increase in diet-borne MeHg accumulation. We used a large-scale field study to evaluate relationships among terrestrial subsidy use, growth, and MeHg concentrations in two stream-dwelling fish species across an in-stream productivity gradient. We sampled young-of-the-year brook trout (Salvelinus fontinalis and Atlantic salmon (Salmo salar, potential competitors with similar foraging habits, from 20 study sites in streams in New Hampshire and Massachusetts that encompassed a wide range of aquatic prey biomass. Stable isotope analysis showed that brook trout used more terrestrial resources than Atlantic salmon. Over their first growing season, Atlantic salmon tended to grow larger than brook trout at sites with high aquatic prey biomass, but brook grew two-fold larger than Atlantic salmon at sites with low aquatic prey biomass. The MeHg concentrations of brook trout and Atlantic salmon were similar at sites with high aquatic prey biomass and the MeHg concentrations of both species increased at sites with low prey biomass and high MeHg in aquatic prey. However, brook trout had three-fold lower MeHg concentrations than Atlantic salmon at low-productivity, high-MeHg sites. These results suggest that differential use of terrestrial resource subsidies reversed the growth asymmetry between potential competitors across a productivity gradient and, for one species, moderated the effect of low in-stream productivity on MeHg accumulation.

  1. Congener Patterns of Persistent Organic Pollutants Establish the Extent of Contaminant Biotransport by Pacific Salmon in the Great Lakes.

    Science.gov (United States)

    Gerig, Brandon S; Chaloner, Dominic T; Janetski, David J; Rediske, Richard R; O'Keefe, James P; Moerke, Ashley H; Lamberti, Gary A

    2016-01-19

    In the Great Lakes, introduced Pacific salmon (Oncorhynchus spp.) can transport persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), to new environments during their spawning migrations. To explore the nature and extent of POP biotransport by salmon, we compared 58 PCB and 6 PBDE congeners found in spawning salmon directly to those in resident stream fish. We hypothesized that stream fish exposed to salmon spawners would have congener patterns similar to those of salmon, the presumed contaminant source. Using permutational multivariate analysis of variance (PERMANOVA) and nonmetric multidimensional scaling (NMDS), we found that POP congener patterns of Pacific salmon varied among regions in the Great Lakes basin (i.e., Lake Huron, Lake Michigan, or Lake Superior), tissue type (whole fish or eggs), and contaminant type (PCB or PBDE). For stream-resident fish, POP congener pattern was influenced by the presence of salmon, location (i.e., Great Lakes Basin), and species identity (i.e., brook trout [Salvelinus fontinalis] or mottled sculpin [Cottus bairdii]). Similarity in congener patterns indicated that salmon are a source of POPs to brook trout in stream reaches receiving salmon spawners from Lake Michigan and Lake Huron but not from Lake Superior. Congener patterns of mottled sculpin differed from those of brook trout and salmon, suggesting that brook trout and mottled sculpin either use salmon tissue to differing degrees, acquire POPs from different dietary sources, or bioaccumulate or metabolize POPs differently. Overall, our analyses identified the important role of salmon in contaminant biotransport but also demonstrated that the extent of salmon-mediated POP transfer and uptake in Great Lakes tributaries is location- and species-specific.

  2. Physiological response of some economically important freshwater salmonids to catch-and-release fishing

    Science.gov (United States)

    Wedemeyer, G.A.; Wydoski, R.S.

    2008-01-01

    Catch-and-release fishing regulations are widely used by fishery resource managers to maintain both the quantity and quality of sport fish populations. We evaluated blood chemistry disturbances in wild brook trout Salvelinus fontinalis, brown trout Salmo trutta, cutthroat trout Oncorhynchus clarkii, and Arctic grayling Thymallus arcticus that had been hooked and played for 1-5 min in waters of the intermountain western United States. A hatchery stock of brown trout was included for comparison. To assess time needed for recovery, additional test groups were played for 5 min and then released into net-pens, where they were held for up to 72 h. The osmoregulatory and metabolic disturbances associated with catch-and-release fishing under the conditions we tested were minimal and judged to be well within normal physiological tolerance limits. In fish that were held for recovery, the blood chemistry alterations that did occur appeared to be related to stress from confinement in the net-pens. Our results confirm the results of previous studies, showing that prerelease air exposure and handling cause more physiological stress than does either hooking per se or playing time. Fishery managers must be aware of the differences in the perceptions, attitudes, and values of different societal groups, some of which feel that catch-and-release fishing should be banned because it is cruel to the animals. On the basis of brain anatomy, it seems highly unlikely that fish experience pain in the same manner as humans experience it, because fish lack a neocortex, the brain structure that enables the sensation of pain in higher vertebrates. However, independent of the neurobiological argument, our results indicate that under conditions similar to those tested, fish subjected to catch and release are neither suffering nor particularly stressed. Improved education programs about the relatively benign physiological effects of catch-and-release fishing as a fishery management practice would

  3. Assessment of Native Salmonids Above Hells Canyon Dam, Idaho, 2002-2003 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Kevin A.; Lamansky, Jr., James A. (Idaho Department of Fish and Game, Boise, ID)

    2004-03-01

    We assessed the relationships between specific stream attributes and Yellowstone cutthroat trout Oncorhynchus clarki bouvieri distribution and biomass at 773 stream reaches (averaging 100 m in length) throughout the Upper Snake River Basin in Idaho, in an effort to identify possible limiting factors. Because limiting factors were expected to vary across the range of cutthroat trout distribution in Idaho, separate logistic and multiple regression models were developed for each of the nine major river drainages to relate stream conditions to occurrence and biomass of cutthroat trout. Adequate stream flow to measure fish and habitat existed at 566 sites, and of those, Yellowstone cutthroat trout were present at 322 sites, while rainbow trout O. mykiss (or rainbow x cutthroat hybrids) and brook trout Salvelinus fontinalis occurred at 108 and 181 sites, respectively. In general, cutthroat trout presence at a specific site within a drainage was associated with a higher percentage of public property, higher elevation, more gravel and less fine substrate, and more upright riparian vegetation. However, there was much variation between drainages in the direction and magnitude of the relationships between stream characteristics and Yellowstone cutthroat trout occurrence and biomass, and in model strength. This was especially true for biomass models, in which we were able to develop models for only five drainages that explained more than 50% of the variation in cutthroat trout biomass. Sample size appeared to affect the strength of the biomass models, with a higher explanation of biomass variation in drainages with lower sample sizes. The occurrence of nonnative salmonids was not strongly related to cutthroat trout occurrence, but their widespread distribution and apparent ability to displace native cutthroat trout suggest they may nevertheless pose the largest threat to long-term cutthroat trout persistence in the Upper Snake River Basin.

  4. Persistent mortality of brook trout in episodically acidified streams of the Southwestern Adirondack Mountains, New York

    Science.gov (United States)

    Baldigo, Barry P.; Lawrence, G.; Simonin, H.

    2007-01-01

    Water chemistry, discharge, and mortality of caged brook trout Salvelinus fontinalis were characterized in six headwater streams in the southwestern Adirondack Mountains of New York during spring 2001-2003. Results were compared with mortality recorded during similar tests during 1984-1985, 1988-1990, and 1997 to assess contemporary relations between stream acidification and brook trout mortality, the effects of exposure duration on mortality, and the effects of decreased rates of acidic deposition on water quality and fish mortality. Water quality and mortality of caged, young-of-the-year brook trout were evaluated during 30-d exposure periods from mid-April to late May during the most recent tests. In 2001-2003, mortality ranged from 0% to 100% and varied among streams and years, depending on the timing of toxicity tests in relation to the annual snowmelt and on the ability of each watershed to neutralize acids and prevent acutely toxic concentrations of inorganic monomeric aluminum (Alim) during high-flow events. Mortality rates in 2001-2003 tests were highly variable but similar to those observed during earlier tests. This similarity suggests that stream water quality in the southwestern Adirondack Mountains has not changed appreciably over the past 20 years. Concentrations of Alim greater than 2.0 and 4.0 ??mol/L were closely correlated with low and high mortality rates, respectively, and accounted for 83% of the variation in mortality. Two to four days of exposure to Alim concentrations greater than 4.0 ??mol/L resulted in 50-100% mortality. The extended periods (as long as 6 months) during which Alim concentrations exceeded 2.0 and 4.0 ??mol/L in one or more streams, combined with the low tolerance of many other fish species to acid and elevated Al concentrations, indicate a high potential for damage to fish communities in these and other poorly buffered streams of the Northeast. ?? Copyright by the American Fisheries Society 2007.

  5. Shale Gas Development and Brook Trout: Scaling Best Management Practices to Anticipate Cumulative Effects

    Science.gov (United States)

    Smith, David; Snyder, Craig D.; Hitt, Nathaniel P.; Young, John A.; Faulkner, Stephen P.

    2012-01-01

    Shale gas development may involve trade-offs between energy development and benefits provided by natural ecosystems. However, current best management practices (BMPs) focus on mitigating localized ecological degradation. We review evidence for cumulative effects of natural gas development on brook trout (Salvelinus fontinalis) and conclude that BMPs should account for potential watershed-scale effects in addition to localized influences. The challenge is to develop BMPs in the face of uncertainty in the predicted response of brook trout to landscape-scale disturbance caused by gas extraction. We propose a decision-analysis approach to formulating BMPs in the specific case of relatively undisturbed watersheds where there is consensus to maintain brook trout populations during gas development. The decision analysis was informed by existing empirical models that describe brook trout occupancy responses to landscape disturbance and set bounds on the uncertainty in the predicted responses to shale gas development. The decision analysis showed that a high efficiency of gas development (e.g., 1 well pad per square mile and 7 acres per pad) was critical to achieving a win-win solution characterized by maintaining brook trout and maximizing extraction of available gas. This finding was invariant to uncertainty in predicted response of brook trout to watershed-level disturbance. However, as the efficiency of gas development decreased, the optimal BMP depended on the predicted response, and there was considerable potential value in discriminating among predictive models through adaptive management or research. The proposed decision-analysis framework provides an opportunity to anticipate the cumulative effects of shale gas development, account for uncertainty, and inform management decisions at the appropriate spatial scales.

  6. Evaluation of an Unsuccessful Brook Trout Electrofishing Removal Project in a Small Rocky Mountain Stream.

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Kevin A.; Lamansky, Jr., James A.; Schill, Daniel J.

    2006-01-26

    In the western United States, exotic brook trout Salvelinus fontinalis frequently have a deleterious effect on native salmonids, and biologists often attempt to remove brook trout from streams by means of electrofishing. Although the success of such projects typically is low, few studies have assessed the underlying mechanisms of failure, especially in terms of compensatory responses. A multiagency watershed advisory group (WAG) conducted a 3-year removal project to reduce brook trout and enhance native salmonids in 7.8 km of a southwestern Idaho stream. We evaluated the costs and success of their project in suppressing brook trout and looked for brook trout compensatory responses, such as decreased natural mortality, increased growth, increased fecundity at length, and earlier maturation. The total number of brook trout removed was 1,401 in 1998, 1,241 in 1999, and 890 in 2000; removal constituted an estimated 88% of the total number of brook trout in the stream in 1999 and 79% in 2000. Although abundance of age-1 and older brook trout declined slightly during and after the removals, abundance of age-0 brook trout increased 789% in the entire stream 2 years after the removals ceased. Total annual survival rate for age-2 and older brook trout did not decrease during the removals, and the removals failed to produce an increase in the abundance of native redband trout Oncorhynchus mykiss gairdneri. Lack of a meaningful decline and unchanged total mortality for older brook trout during the removals suggest that a compensatory response occurred in the brook trout population via reduced natural mortality, which offset the removal of large numbers of brook trout. Although we applaud WAG personnel for their goal of enhancing native salmonids by suppressing brook trout via electrofishing removal, we conclude that their efforts were unsuccessful and suggest that similar future projects elsewhere over such large stream lengths would be costly, quixotic enterprises.

  7. Exploring crowded trophic niche space in a novel reservoir fish assemblage: how many predators is too many?

    Science.gov (United States)

    Winters, Lisa K.; Budy, Phaedra

    2015-01-01

    In highly managed reservoir systems, species interactions within novel fish assemblages can be difficult to predict. In high-elevation Scofield Reservoir in Utah the unintentional introduction of Utah Chub Gila atraria and subsequent population expansion prompted a shift from stocking exclusively Rainbow Trout Oncorhynchus mykiss to include tiger trout (female Brown Trout Salmo trutta × male Brook Trout Salvelinus fontinalis) and Bonneville Cutthroat Trout O. clarkii utah, which composed a novel suite of top predators and potential competitors. We examined the interspecific interactions among Scofield Reservoir piscivores using a multifaceted approach including gut analyses, stable isotopes, and gape limitation. Large Cutthroat Trout consumed 50–100% Utah Chub and tiger trout consumed 45–80%. In contrast, small and large Rainbow Trout consumed primarily invertebrate prey and exhibited significant overlap with small tiger trout, Cutthroat Trout, and Utah Chub. Large Cutthroat Trout and tiger trout occupy a top piscivore trophic niche and are more littoral, while Rainbow Trout occupy an omnivore niche space and are more pelagic. Both Cutthroat and tiger trout varied in niche space with respect to size-class, demonstrating an ontogenetic shift to piscivory at approximately 350 mm TL. Cutthroat Trout and tiger trout are capable of consuming prey up to 50% of their own size, which is larger than predicted based on their theoretical gape limit. Because it appears food resources (Utah Chub) are not limited, and performance metrics are high, competition is unlikely between Cutthroat Trout and tiger trout. In contrast, apparent survival of Rainbow Trout has recently declined significantly, potentially due to shared food resources with Utah Chub or negative behavioral interactions with other members of the community. Collectively, this research aids in understanding biotic interactions within a top-heavy and novel fish community and assists towards developing

  8. Phylogeny of Salmonidae family inffered from D-loop mitochondrial marker

    Directory of Open Access Journals (Sweden)

    Miad Khalaf

    2014-05-01

    Full Text Available Normal 0 false false false MicrosoftInternetExplorer4 Salmonids are a heterogeneous group of fish classified in one family – Salmonidae. These species are natives of the northern hemisphere, but currently have been introduced in many countries all over the world for sport fishing and aquaculture. Despite the considerable importance of salmonids, their evolutive history is still a controversial issue. The aim of the current study is to infer the phylogeny within the Salmonidae family using as phylogenetic marker the D-loop region. For this purpose, an PCR amplification of D-loop region, followed by direct sequencing and phylogenetic analysis have been performed in four salmonids species from Romanian fauna - Salmo trutta fario, Salvelinus fontinalis, Thymallus thymallus and Oncorhynchus mykiss. For a more accurate phylogenetic classification of these species within Salmonidae family the analysis included similar sequences from GenBank belonging to 17 salmonid species and an osmerid species used as outgroup. The the phylogenetic trees illustrating the evolutive relationships within Salmonidae were constructed by using Neighbor Joining and Maximum Parsimony methodologies implemented in MEGA5.The phylogenetic analysis using mitochondrial control region as marker has allowed an overview about the positions occupied by Romanian salmonids within the Salmonidae family. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;}

  9. Description of Gyrodactylus mediotorus n. sp. (Monogenea: Gyrodactylidae) infecting spottail shiner (Notropis hudsonius) from the St. Lawrence River, Canada.

    Science.gov (United States)

    King, Stanley D; Marcogliese, David J; Forest, Jonathon J H; McLaughlin, J Daniel; Bentzen, Paul

    2013-12-01

    Gyrodactylus mediotorus n. sp. is described from the body, fins, and buccal cavity of the spottail shiner, Notropis hudsonius (Cyprinidae) from the St. Lawrence River, Quebec, Canada. Gyrodactylus mediotorus n. sp. is the first species of Gyrodactylus Nordmann, 1832 described from N. hudsonius and is characterized by large hamuli, large medial process of the ventral bar, narrow linguiform ventral bar membrane, large anterolateral processes, and marginal hooks with long shafts and distinctly shaped sickle. The species that most resembles Gyrodactylus mediotorus n. sp. is Gyrodactylus protuberus Rogers and Wellborn, 1965 described from the stargazing shiner, Notropis uranoscopus Suttkus, 1959. The 2 species can be differentiated based on the larger hamuli (68.4 vs. 64) and ventral bar (38.4 vs. 24) of Gyrodactylus mediotorus n. sp. and the shape of the marginal hooks which for Gyrodactylus mediotorus n. sp. has a slightly larger toe and a point which is not as angled. The morphological description is supplemented with 436 sequenced base pairs of the 18S gene (including the V4 region) as well as 1,041 sequenced base pairs spanning the complete ITS-1, 5.8S, and ITS-2 regions. BLAST (Basic Local Alignment Search Tool) searches failed to provide any close matches for either regions of DNA, with Gyrodactylus colemanensis infecting Salvelinus fontinalis being the most genetically similar for both the 18S (∼91%, JF836090) and ITS (∼84%, JF836142) rDNA regions. Gyrodactylus mediotorus n. sp. has been found infecting spottail shiners in the St. Lawrence River in low prevalence and intensities periodically over the last 15 yr. PMID:23883192

  10. A comparative and experimental evaluation of performance of stocked diploid and triploid brook trout

    Science.gov (United States)

    Budy, Phaedra E.; Thiede, G.P.; Dean, A.; Olsen, D.; Rowley, G.

    2012-01-01

    Despite numerous negative impacts, nonnative trout are still being stocked to provide economically and socially valuable sport fisheries in western mountain lakes. We evaluated relative performance and potential differences in feeding strategy and competitive ability of triploid versus diploid brook trout Salvelinus fontinalis in alpine lakes, as well as behavioral and performance differences of diploid and triploid brook trout in two controlled experimental settings: behavioral experiments in the laboratory and performance evaluations in ponds. Across lakes, catch per unit effort (CPUE) and relative weight (Wr ) were not significantly different between ploidy levels. Mean sizes were also similar between ploidy levels except in two of the larger lakes where diploids attained slightly larger sizes (approximately 20 mm longer). We observed no significant differences between diploids and triploids in diet, diet preference, or trophic structure. Similarly, growth and condition did not differ between ploidy levels in smaller-scale pond experiments, and aggressive behavior did not differ between ploidy levels (fed or unfed fish trials) in the laboratory. Independent of ploidy level, the relative performance of brook trout varied widely among lakes, a pattern that appeared to be a function of lake size or a factor that covaries with lake size such as temperature regime or carrying capacity. In summary, we observed no significant differences in the relative performance of brook trout from either ploidy level across a number of indices, systems, and environmental conditions, nor any indication that one group is more aggressive or a superior competitor than the other. Collectively, these results suggest that triploid brook trout will offer a more risk-averse and promising management opportunity when they are stocked to these lakes and elsewhere to simultaneously meet the needs for the sport fishery and conservation objectives.

  11. Impact of Forest Harvesting on Trophic Structure of Eastern Canadian Boreal Shield Lakes: Insights from Stable Isotope Analyses

    Science.gov (United States)

    Glaz, Patricia; Sirois, Pascal; Archambault, Philippe; Nozais, Christian

    2014-01-01

    Perturbations on ecosystems can have profound immediate effects and can, accordingly, greatly alter the natural community. Land-use such as forestry activities in the Canadian Boreal region have increased in the last decades, raising concerns about their potential impact on aquatic ecosystems. The objective of this study was to evaluate the impact of forest harvesting on trophic structure in eastern Canadian Boreal Shield lakes. We measured carbon and nitrogen stable isotopes values for aquatic primary producers, terrestrial detritus, benthic macroinvertebrates, zooplankton and brook trout (Salvelinus fontinalis) over a three-year period in eight eastern Boreal Shield lakes. Four lakes were studied before, one and two years after forest harvesting (perturbed lakes) and compared with four undisturbed reference lakes (unperturbed lakes) sampled at the same time. Stable isotope mixing models showed leaf-litter to be the main food source for benthic primary consumers in both perturbed and unperturbed lakes, suggesting no logging impact on allochthonous subsidies to the littoral food web. Brook trout derived their food mainly from benthic predatory macroinvertebrates in unperturbed lakes. However, in perturbed lakes one year after harvesting, zooplankton appeared to be the main contributor to brook trout diet. This change in brook trout diet was mitigated two years after harvesting. Size-related diet shift were also observed for brook trout, indicating a diet shift related to size. Our study suggests that carbon from terrestrial habitat may be a significant contribution to the food web of oligotrophic Canadian Boreal Shield lakes. Forest harvesting did not have an impact on the diet of benthic primary consumers. On the other hand, brook trout diet composition was affected by logging with greater zooplankton contribution in perturbed lakes, possibly induced by darker-colored environment in these lakes one year after logging. PMID:24763366

  12. The effects of varied densities on the growth and emigration of adult cutthroat trout and brook trout in fenced stream enclosures

    Science.gov (United States)

    Buys, D.J.; Hilderbrand, R.H.; Kershner, J.L.

    2009-01-01

    We evaluated the effects of various density treatments on adult fish growth and emigration rates between Bonneville cutthroat trout Oncorhynchus clarki utah and brook trout Salvelinus fontinalis in stream enclosures in Beaver Creek, Idaho, We used 3 density treatments (low, ambient, and high fish densities) to evaluate density-related effects and to ensure a response. Intraspecific ambient-density tests using cutthroat trout only were also performed. Results indicated an absence of cage effects in the stream enclosures and no differences in fish growth between ambient-density stream-enclosure fish and free-range fish. Brook trout outgrew and moved less than cutthroat trout in the stream enclosures, especially as density increased, In all 3 density treatments, brook trout gained more weight than cutthroat trout, with brook trout gaining weight in each density treatment and cutthroat trout losing weight at the highest density. At high densities, cutthroat trout attempted to emigrate more frequently than brook trout in sympatry and allopatry. We observed a negative correlation between growth and emigration for interspecific cutthroat trout, indicating a possible competitive response due to the presence of brook trout. We observed similar responses for weight and emigration in trials of allopatric cutthroat trout, indicating strong intraspecific effects as density increased. While cutthroat trout showed a response to experimental manipulation with brook trout at different densities, there has been long-term coexistence between these species in Beaver Creek, This system presents a unique opportunity to study the mechanisms that lead cutthroat trout to coexist with rather than be replaced by nonnative brook trout.

  13. Evaluation of Infrasound and Strobe Lights to Elicit Avoidance Behavior in Juvenile Salmon and Char.

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Robert, P.; Neitzel, Duane A.; Amidan, Brett G.

    1999-02-01

    Experimental tests were conducted using hatchery reared and wild juvenile chinook salmon Oncorhynchus tshawytscha, eastern brook trout Salvelinus fontinalis, and rainbow trout O. mykiss to determine specific behavior responses to infrasound (<20 Hz) and flashing strobe lights. Caged fish were acclimated in a static test tank and their behavior was recorded using low light cameras. Species specific behavior was characterized by measuring movements of the fish within the cage as well as observing startle and habituation responses. Wild chinook salmon (40-45 mm) and hatchery reared chinook salmon (45-50mm) exhibited avoidance responses when initially exposed to a 10 Hz volume displacement source. Rainbow and eastern brook trout (25-100 mm) did not respond with avoidance or other behaviors to infrasound. Habituation to the infrasound source was evident for chinook salmon during repeated exposures. Wild and hatchery chinook displayed a higher proportion of movement during the initial exposures to infrasound when the acclimation period in the test tank was 2-3 h as compared to a 12-15 h acclimation period. A flashing strobe light produced higher and more consistent movement rates in wild chinook (60% of the tests); hatchery reared chinook salmon (50%) and rainbow trout (80%). No measurable movement or other responses was observed for eastern brook trout. Little if any habituation was observed during repeated exposures to strobe lights. Results from this study indicate that consistent repeatable responses can be elicited from some fish using high intensity strobe lights under a controlled laboratory testing. The specific behaviors observed in these experiments might be used to predict how fish might react to low frequency sound and strobe lights in a screening facility. Because sub-yearling salmonids and resident species are susceptible from becoming entrained at water diversion structures we conducted tests in conjunction with our evaluation of juvenile fish screening

  14. An evaluation of the precision of fin ray, otolith, and scale age determinations for brook trout

    Science.gov (United States)

    Stolarski, J.T.; Hartman, K.J.

    2008-01-01

    The ages of brook trout Salvelinus fontinalis are typically estimated using scales despite a lack of research documenting the effectiveness of this technique. The use of scales is often preferred because it is nonlethal and is believed to require less effort than alternative methods. To evaluate the relative effectiveness of different age estimation methodologies for brook trout, we measured the precision and processing times of scale, sagittal otolith, and pectoral fin ray age estimation techniques. Three independent readers, age bias plots, coefficients of variation (CV = 100 x SD/mean), and percent agreement (PA) were used to measure within-reader, among-structure bias and within-structure, among-reader precision. Bias was generally minimal; however, the age estimates derived from scales tended to be lower than those derived from otoliths within older (age > 2) cohorts. Otolith, fin ray, and scale age estimates were within 1 year of each other for 95% of the comparisons. The measures of precision for scales (CV = 6.59; PA = 82.30) and otoliths (CV = 7.45; PA = 81.48) suggest higher agreement between these structures than with fin rays (CV = 11.30; PA = 65.84). The mean per-sample processing times were lower for scale (13.88 min) and otolith techniques (12.23 min) than for fin ray techniques (22.68 min). The comparable processing times of scales and otoliths contradict popular belief and are probably a result of the high proportion of regenerated scales within samples and the ability to infer age from whole (as opposed to sectioned) otoliths. This research suggests that while scales produce age estimates rivaling those of otoliths for younger (age > 3) cohorts, they may be biased within older cohorts and therefore should be used with caution. ?? Copyright by the American Fisheries Society 2008.

  15. Broad-scale patterns of Brook Trout responses to introduced Brown Trout in New York

    Science.gov (United States)

    McKenna Jr, James E.; Slattery, Michael T.; Kean M. Clifford

    2013-01-01

    Brook Trout Salvelinus fontinalis and Brown Trout Salmo trutta are valuable sport fish that coexist in many parts of the world due to stocking introductions. Causes for the decline of Brook Trout within their native range are not clear but include competition with Brown Trout, habitat alteration, and repetitive stocking practices. New York State contains a large portion of the Brook Trout's native range, where both species are maintained by stocking and other management actions. We used artificial neural network models, regression, principal components analysis, and simulation to evaluate the effects of Brown Trout, environmental conditions, and stocking on the distribution of Brook Trout in the center of their native range. We found evidence for the decline of Brook Trout in the presence of Brown Trout across many watersheds; 22% of sampled reaches where both species were expected to occur contained only Brown Trout. However, a model of the direct relationship between Brook Trout and Brown Trout abundance explained less than 1% of data variation. Ordination showed extensive overlap of Brook Trout and Brown Trout habitat conditions, with only small components of the hypervolume (multidimensional space) being distinctive. Subsequent analysis indicated higher abundances of Brook Trout in highly forested areas, while Brown Trout were more abundant in areas with relatively high proportions of agriculture. Simulation results indicated that direct interactions and habitat conditions were relatively minor factors compared with the effects of repeated stocking of Brown Trout into Brook Trout habitat. Intensive annual stocking of Brown Trout could eliminate resident Brook Trout in less than a decade. Ecological differences, harvest behavior, and other habitat changes can exacerbate Brook Trout losses. Custom stocking scenarios with Brown Trout introductions at relatively low proportions of resident Brook Trout populations may be able to sustain healthy populations of both

  16. Brown trout and food web interactions in a Minnesota stream

    Science.gov (United States)

    Zimmerman, J.K.H.; Vondracek, B.

    2007-01-01

    1. We examined indirect, community-level interactions in a stream that contained non-native brown trout (Salmo trutta Linnaeus), native brook trout (Salvelinus fontinalis Mitchill) and native slimy sculpin (Cottus cognatus Richardson). Our objectives were to examine benthic invertebrate composition and prey selection of fishes (measured by total invertebrate dry mass, dry mass of individual invertebrate taxa and relative proportion of invertebrate taxa in the benthos and diet) among treatments (no fish, juvenile brook trout alone, juvenile brown trout alone, sculpin with brook trout and sculpin with brown trout). 2. We assigned treatments to 1 m2 enclosures/exclosures placed in riffles in Valley Creek, Minnesota, and conducted six experimental trials. We used three designs of fish densities (addition of trout to a constant number of sculpin with unequal numbers of trout and sculpin; addition of trout to a constant number of sculpin with equal numbers of trout and sculpin; and replacement of half the sculpin with an equal number of trout) to investigate the relative strength of interspecific versus intraspecific interactions. 3. Presence of fish (all three species, alone or in combined-species treatments) was not associated with changes in total dry mass of benthic invertebrates or shifts in relative abundance of benthic invertebrate taxa, regardless of fish density design. 4. Brook trout and sculpin diets did not change when each species was alone compared with treatments of both species together. Likewise, we did not find evidence for shifts in brown trout or sculpin diets when each species was alone or together. 5. We suggest that native brook trout and non-native brown trout fill similar niches in Valley Creek. We did not find evidence that either species had an effect on stream communities, potentially due to high invertebrate productivity in Valley Creek. ?? 2007 Blackwell Publishing Ltd.

  17. Landscape-scale evaluation of asymmetric interactions between Brown Trout and Brook Trout using two-species occupancy models

    Science.gov (United States)

    Wagner, Tyler; Jefferson T. Deweber; Jason Detar; John A. Sweka

    2013-01-01

    Predicting the distribution of native stream fishes is fundamental to the management and conservation of many species. Modeling species distributions often consists of quantifying relationships between species occurrence and abundance data at known locations with environmental data at those locations. However, it is well documented that native stream fish distributions can be altered as a result of asymmetric interactions between dominant exotic and subordinate native species. For example, the naturalized exotic Brown Trout Salmo trutta has been identified as a threat to native Brook Trout Salvelinus fontinalis in the eastern United States. To evaluate large-scale patterns of co-occurrence and to quantify the potential effects of Brown Trout presence on Brook Trout occupancy, we used data from 624 stream sites to fit two-species occupancy models. These models assumed that asymmetric interactions occurred between the two species. In addition, we examined natural and anthropogenic landscape characteristics we hypothesized would be important predictors of occurrence of both species. Estimated occupancy for Brook Trout, from a co-occurrence model with no landscape covariates, at sites with Brown Trout present was substantially lower than sites where Brown Trout were absent. We also observed opposing patterns for Brook and Brown Trout occurrence in relation to percentage forest, impervious surface, and agriculture within the network catchment. Our results are consistent with other studies and suggest that alterations to the landscape, and specifically the transition from a forested catchment to one that contains impervious surface or agriculture, reduces the occurrence probability of wild Brook Trout. Our results, however, also suggest that the presence of Brown Trout results in lower occurrence probability of Brook Trout over a range of anthropogenic landscape characteristics, compared with streams where Brown Trout were absent.

  18. Changes in seasonal climate outpace compensatory density-dependence in eastern brook trout

    Science.gov (United States)

    Bassar, Ronald D.; Letcher, Benjamin H.; Nislow, Keith H.; Whiteley, Andrew R.

    2016-01-01

    Understanding how multiple extrinsic (density-independent) factors and intrinsic (density-dependent) mechanisms influence population dynamics has become increasingly urgent in the face of rapidly changing climates. It is particularly unclear how multiple extrinsic factors with contrasting effects among seasons are related to declines in population numbers and changes in mean body size and whether there is a strong role for density-dependence. The primary goal of this study was to identify the roles of seasonal variation in climate driven environmental direct effects (mean stream flow and temperature) versus density-dependence on population size and mean body size in eastern brook trout (Salvelinus fontinalis). We use data from a 10-year capture-mark-recapture study of eastern brook trout in four streams in Western Massachusetts, USA to parameterize a discrete-time population projection model. The model integrates matrix modeling techniques used to characterize discrete population structures (age, habitat type and season) with integral projection models (IPMs) that characterize demographic rates as continuous functions of organismal traits (in this case body size). Using both stochastic and deterministic analyses we show that decreases in population size are due to changes in stream flow and temperature and that these changes are larger than what can be compensated for through density-dependent responses. We also show that the declines are due mostly to increasing mean stream temperatures decreasing the survival of the youngest age class. In contrast, increases in mean body size over the same period are the result of indirect changes in density with a lesser direct role of climate-driven environmental change.

  19. Robust detection of rare species using environmental DNA: the importance of primer specificity.

    Directory of Open Access Journals (Sweden)

    Taylor M Wilcox

    Full Text Available Environmental DNA (eDNA is being rapidly adopted as a tool to detect rare animals. Quantitative PCR (qPCR using probe-based chemistries may represent a particularly powerful tool because of the method's sensitivity, specificity, and potential to quantify target DNA. However, there has been little work understanding the performance of these assays in the presence of closely related, sympatric taxa. If related species cause any cross-amplification or interference, false positives and negatives may be generated. These errors can be disastrous if false positives lead to overestimate the abundance of an endangered species or if false negatives prevent detection of an invasive species. In this study we test factors that influence the specificity and sensitivity of TaqMan MGB assays using co-occurring, closely related brook trout (Salvelinus fontinalis and bull trout (S. confluentus as a case study. We found qPCR to be substantially more sensitive than traditional PCR, with a high probability of detection at concentrations as low as 0.5 target copies/µl. We also found that number and placement of base pair mismatches between the Taqman MGB assay and non-target templates was important to target specificity, and that specificity was most influenced by base pair mismatches in the primers, rather than in the probe. We found that insufficient specificity can result in both false positive and false negative results, particularly in the presence of abundant related species. Our results highlight the utility of qPCR as a highly sensitive eDNA tool, and underscore the importance of careful assay design.

  20. Frequency and Severity of Trauma in Fishes Subjected to Multiple-pass Depletion Electrofishing

    Science.gov (United States)

    Panek, Frank; Densmore, Christine L.

    2013-01-01

    The incidence and severity of trauma associated with multiple-pass electrofishing and the effects on short-term (30-d) survival and growth of Rainbow Trout Oncorhynchus mykiss, Brook Trout Salvelinus fontinalis, and five representative co-inhabiting nontarget or bycatch species were examined. Fish were held in four rectangular fiberglass tanks (190 × 66 cm) equipped with electrodes, a gravel–cobble stream substrate, and continuous water flow. Fish were exposed to one, two, or three electroshocks (100-V, 60-Hz pulsed DC) spaced 1 h apart or were held as a control. The heterogeneous field produced a mean (±SD) voltage gradient of 0.23 ± 0.024 V/cm (range = 0.20–0.30 V/cm) with a duty cycle of 30% and a 5-s exposure. Radiographs of 355 fish were examined for evidence of spinal injuries, and necropsies were performed on 303 fish to assess hemorrhagic trauma in soft tissue. Using linear regression, we demonstrated significant relationships between the number of electrical shocks and the frequency and severity of hemorrhagic and spinal trauma in each of the nontarget species (Potomac Sculpin Cottus girardi, Channel Catfish Ictalurus punctatus, Fathead Minnow Pimephales promelas, Green Sunfish Lepomis cyanellus, and Largemouth Bass Micropterus salmoides). Most of the injuries in these species were either minor or moderate. Rainbow Trout and Brook Trout generally sustained the highest incidence and severity of injuries, but those injuries were generally independent of the number of treatments. The 30-d postshock survival for the trout species was greater than 94%; survival for the bycatch species ranged from 80% (Fathead Minnow) to 100% (Green Sunfish and Channel Catfish). There were no significant differences in 30-d postshock condition factors despite observations of altered feeding behavior lasting several days to 1 week posttreatment in several of the study species.

  1. Bull Trout life History, Genetics, Habitat Needs, and Limiting Factors in Central and Northeast Oregon, Annual Report 1995.

    Energy Technology Data Exchange (ETDEWEB)

    Hemmingsen, Alan R.; Buchanan, David V.; Howell, Philip J.

    1996-03-01

    To fulfill one objective of the present study, genetic characteristics of Oregon bull trout will be determined by analysis of mitochondrial and nuclear DNA. During 1995, the authors collected and sampled a total of 1,217 bull trout from 46 streams in the Columbia River Basin. DNA analysis of those samples will be conducted at University of Montana. They primarily sampled juvenile fish near natal areas to increase the likelihood of identifying discrete populations while minimizing risk of injury to large spawners. Fork lengths of all fish sampled ranged from 2.6 to 60.5 cm with a median of 12 cm. Eighty-four percent of all bull trout sampled were less than 19 cm while two percent were larger than 27 cm. Bull trout were collected by several methods, mostly by electrofishing. Eighty-six percent of all bull trout sampled were collected by electrofishing with a programmable waveform electrofisher. They observed injuries caused by electrofishing to 8% of that proportion. Based on preliminary analysis, no waveform combination used appeared less injurious than others. Highest voltages appeared less injurious than some that were lower. Frequency of electrofishing injury was significantly correlated to fork length over the range-from 4 to 26 cm. There were indications for substantial risk for such injury to bull trout larger than 26 cm. Other species found in association with bull trout included chinook salmon Oncorhynchus tshawytscha, mountain whitefish Prosopium williamsoni, rainbow trout Oncorhynchus mykiss, sculpins Cottus spp., cutthroat trout Oncorhynchus clarki, non-native brook trout Salvelinus fontinalis, and tailed frogs Ascaphus truei. Rainbow trout was the species most frequently associated with bull trout. No injury or mortality was observed for any of the associated species captured.

  2. Stochastic life history modeling for managing regional-scale freshwater fisheries: an experimental study of brook trout.

    Science.gov (United States)

    Adams, Blair K; Cote, David; Fleming, Ian A

    2016-04-01

    Environmental heterogeneity can combine with evolutionary responses to create very dynamic and often locally independent populations across a landscape. Such complexity creates difficulties for managers trying to conserve populations across large areas. This study develops, applies, and tests the use of stochastic life history modeling and Monte Carlo simulation to assess management scenarios related to the realities of regional fisheries management and conservation. We apply this approach to the management of recreational brook trout (Salvelinus fontinalis) fishing; an activity that can severely impact species balance, abundance, and the size structure of fish communities. Specifically, the model incorporates population-specific life-history information (e.g., growth rate, reproductive effort, and survival) to allow forecasts of the impact of various management strategies and/or changes to environmental conditions on a population's ecological characteristics (e.g., size structure, abundance, and probability of persistence). Sampling was carried out in 16 water bodies spread across four sites in Atlantic Canada. Each water body was sampled in 2005 and reassessed in 2008. This sampling had two primary objectives: (1) define a significant proportion of life-history variation of brook trout in Atlantic Canada, and (2) to test the precision and accuracy of model predictions of population responses to experimental exploitation and management changes. The model successfully predicted population responses to changes in adult survival in 12 of 13 populations having sufficient data for validation testing, while also proving to be a useful tool when engaging stakeholders regarding management options and their associated risk. We suggest that such models are cost-effective and have great potential for informing proactive management of jurisdictions with numerous and diverse populations. PMID:27411259

  3. Spatial structure of morphological and neutral genetic variation in Brook Trout

    Science.gov (United States)

    Kazyak, David C.; Hilderbrand, Robert H.; Keller, Stephen R.; Colaw, Mark C.; Holloway, Amanda E.; Morgan, Raymond P.; King, Timothy L.

    2015-01-01

    Brook Trout Salvelinus fontinalis exhibit exceptional levels of life history variation, remarkable genetic variability, and fine-scale population structure. In many cases, neighboring populations may be highly differentiated from one another to an extent that is comparable with species-level distinctions in other taxa. Although genetic samples have been collected from hundreds of populations and tens of thousands of individuals, little is known about whether differentiation at neutral markers reflects phenotypic differences among Brook Trout populations. We compared differentiation in morphology and neutral molecular markers among populations from four geographically proximate locations (all within 24 km) to examine how genetic diversity covaries with morphology. We found significant differences among and/or within streams for all three morphological axes examined and identified the source stream of many individuals based on morphology (52.3% classification efficiency). Although molecular and morphological differentiation among streams ranged considerably (mean pairwise FST: 0.023–0.264; pairwise PST: 0.000–0.339), the two measures were not significantly correlated. While in some cases morphological characters appear to have diverged to a greater extent than expected by neutral genetic drift, many traits were conserved to a greater extent than were neutral genetic markers. Thus, while Brook Trout exhibit fine-scale spatial patterns in both morphology and neutral genetic diversity, these types of biological variabilities are being structured by different ecological and evolutionary processes. The relative influences of genetic drift versus selection and phenotypic plasticity in shaping morphology appear to vary among populations occupying nearby streams.

  4. Seasonal Change in Trophic Niche of Adfluvial Arctic Grayling (Thymallus arcticus) and Coexisting Fishes in a High-Elevation Lake System

    Science.gov (United States)

    Cutting, Kyle A.; Cross, Wyatt F.; Anderson, Michelle L.; Reese, Elizabeth G.

    2016-01-01

    Introduction of non-native species is a leading threat to global aquatic biodiversity. Competition between native and non-native species is often influenced by changes in suitable habitat or food availability. We investigated diet breadth and degree of trophic niche overlap for a fish assemblage of native and non-native species inhabiting a shallow, high elevation lake system. This assemblage includes one of the last remaining post-glacial endemic populations of adfluvial Arctic grayling (Thymallus arcticus) in the contiguous United States. We examined gut contents and stable isotope values of fish taxa in fall and spring to assess both short- (days) and long-term (few months) changes in trophic niches. We incorporate these short-term (gut contents) data into a secondary isotope analysis using a Bayesian statistical framework to estimate long-term trophic niche. Our data suggest that in this system, Arctic grayling share both a short- and long-term common food base with non-native trout of cutthroat x rainbow hybrid species (Oncorhynchus clarkia bouvieri x Oncorhynchus mykiss) and brook trout (Salvelinus fontinalis). In addition, trophic niche overlap among Arctic grayling, hybrid trout, and brook trout appeared to be stronger during spring than fall. In contrast, the native species of Arctic grayling, burbot (Lota lota), and suckers (Catostomus spp.) largely consumed different prey items. Our results suggest strong seasonal differences in trophic niche overlap among Arctic grayling and non-native trout, with a potential for greatest competition for food during spring. We suggest that conservation of endemic Arctic grayling in high-elevation lakes will require recognition of the potential for coexisting non-native taxa to impede well-intentioned recovery efforts. PMID:27205901

  5. Identifying trout refuges in the Indian and Hudson Rivers in northern New York through airborne thermal infrared remote sensing

    Science.gov (United States)

    Ernst, Anne G.; Baldigo, Barry P.; Calef, Fred J.; Freehafer, Douglas A.; Kremens, Robert L.

    2015-10-09

    The locations and sizes of potential cold-water refuges for trout were examined in 2005 along a 27-kilometer segment of the Indian and Hudson Rivers in northern New York to evaluate the extent of refuges, the effects of routine flow releases from an impoundment, and how these refuges and releases might influence trout survival in reaches that otherwise would be thermally stressed. This river segment supports small populations of brook trout (Salvelinus fontinalis), brown trout (Salmo trutta), and rainbow trout (Oncorhynchus mykiss) and also receives regular releases of reservoir-surface waters to support rafting during the summer, when water temperatures in both the reservoir and the river frequently exceed thermal thresholds for trout survival. Airborne thermal infrared imaging was supplemented with continuous, in-stream temperature loggers to identify potential refuges that may be associated with tributary inflows or groundwater seeps and to define the extent to which the release flows decrease the size of existing refuges. In general, the release flows overwhelmed the refuge areas and greatly decreased the size and number of the areas. Mean water temperatures were unaffected by the releases, but small-scale heterogeneity was diminished. At a larger scale, water temperatures in the upper and lower segments of the reach were consistently warmer than in the middle segment, even during passage of release waters. The inability of remote thermal infrared images to consistently distinguish land from water (in shaded areas) and to detect groundwater seeps (away from the shallow edges of the stream) limited data analysis and the ability to identify potential thermal refuge areas.

  6. Impacts of climatic variation on trout: A global synthesis and path forward

    Science.gov (United States)

    Kovach, Ryan; Muhlfeld, Clint C.; Al-Chokhachy, Robert K.; Dunham, Jason; Letcher, Benjamin; Kershner, Jeffrey L.

    2016-01-01

    Despite increasing concern that climate change may negatively impact trout—a globally distributed group of fish with major economic, ecological, and cultural value—a synthetic assessment of empirical data quantifying relationships between climatic variation and trout ecology does not exist. We conducted a systematic review to describe how temporal variation in temperature and streamflow influences trout ecology in freshwater ecosystems. Few studies (n = 42) have quantified relationships between temperature or streamflow and trout demography, growth, or phenology, and nearly all estimates (96 %) were for Salvelinus fontinalis and Salmo trutta. Only seven studies used temporal data to quantify climate-driven changes in trout ecology. Results from these studies were beset with limitations that prohibited quantitatively rigorous meta-analysis, a concerning inadequacy given major investment in trout conservation and management worldwide. Nevertheless, consistent patterns emerged from our synthesis, particularly a positive effect of summer streamflow on trout demography and growth; 64 % of estimates were positive and significant across studies, age classes, species, and locations, highlighting that climate-induced changes in hydrology may have numerous consequences for trout. To a lesser degree, summer and fall temperatures were negatively related to population demography (51 and 53 % of estimates, respectively), but temperature was rarely related to growth. To address limitations and uncertainties, we recommend: (1) systematically improving data collection, description, and sharing; (2) appropriately integrating climate impacts with other intrinsic and extrinsic drivers over the entire lifecycle; (3) describing indirect consequences of climate change; and (4) acknowledging and describing intrinsic resiliency.

  7. Current status, between-year comparisons and maternal transfer of organohalogenated compounds (OHCs) in Arctic char (Salvelinus alpinus) from Bjørnøya, Svalbard (Norway)

    Energy Technology Data Exchange (ETDEWEB)

    Bytingsvik, J., E-mail: jenny.bytingsvik@akvaplan.niva.no [Akvaplan-niva AS, The Fram Centre, N-9296 Tromsø Norway (Norway); Frantzen, M. [Akvaplan-niva AS, The Fram Centre, N-9296 Tromsø Norway (Norway); Götsch, A.; Heimstad, E.S. [NILU (Norwegian Institute for Air Research), The Fram Centre, N-9296 Tromsø Norway (Norway); Christensen, G. [Akvaplan-niva AS, The Fram Centre, N-9296 Tromsø Norway (Norway); Evenset, A. [Akvaplan-niva AS, The Fram Centre, N-9296 Tromsø Norway (Norway); University of Tromsø, The Arctic University of Norway, Pb 6050 Langnes, N-9037 Tromsø (Norway)

    2015-07-15

    High levels of organohalogenated compounds (OHCs) have been found in Arctic char from Lake Ellasjøen at Bjørnøya (Svalbard, Norway) compared to char from other arctic lakes. The first aim of the study was to investigate the OHC status, contaminant profile, and partitioning of OHCs between muscle and ovary tissue in spawning female char from the high-polluted Lake Ellasjøen and the low-polluted Lake Laksvatn. The second aim was to investigate if OHC levels in muscle tissue have changed over time. Between-lake comparisons show that the muscle levels (lipid weight) of hexachlorobenzene (HCB), chlordanes (∑ CHLs), mirex, dichlorodiphenyltrichloroethanes (∑ DDTs) and polychlorinated biphenyls (∑ PCBs) were up to 36 times higher in char from Ellasjøen than in Laksvatn, and confirm that the char from Ellasjøen are still heavily exposed compared to char from neighboring lake. A higher proportion of persistent OHCs were found in Ellasjøen compared to Laksvatn, while the proportion of the less persistent OHCs was highest in Laksvatn. A between-year comparison of OHC levels (i.e., HCB, DDTs, PCBs) in female and male char shows higher levels of HCB in female char from Ellasjøen in 2009/2012 compared to in 1999/2001. No other between-year differences in OHC levels were found. Due to small study groups, findings associated with between-year differences in OHC levels should be interpreted with caution. OHCs accumulate in the lipid rich ovaries of spawning females, resulting in up to six times higher levels of OHCs in ovaries compared to in muscle (wet weight). The toxic equivalent (TEQ)-value for the dioxin-like PCBs (PCB-105 and -118) in ovaries of the Ellasjøen char exceeded levels associated with increased egg mortality in rainbow trout (Oncorhynchus mykiss). Hence, we suggest that future studies should focus on the reproductive health and performance abilities of the high-exposed population of char inhabiting Lake Ellasjøen. - Highlights: • Examine levels, profile, time-trends and maternal transfer of OHCs in Arctic char • Char from Lake Ellasjøen (Bjørnøya, Norway) are known to be highly contaminated. • PCB-levels (2012): 36 times higher in char from Ellasjøen than in Laksvatn (ref.) • Higher HCB levels in female char from Ellasjøen in 2009/2012 than in 1999/2001 • OHC-levels were up to six times higher in ovaries than in muscle tissue.

  8. Current status, between-year comparisons and maternal transfer of organohalogenated compounds (OHCs) in Arctic char (Salvelinus alpinus) from Bjørnøya, Svalbard (Norway).

    Science.gov (United States)

    Bytingsvik, J; Frantzen, M; Götsch, A; Heimstad, E S; Christensen, G; Evenset, A

    2015-07-15

    High levels of organohalogenated compounds (OHCs) have been found in Arctic char from Lake Ellasjøen at Bjørnøya (Svalbard, Norway) compared to char from other arctic lakes. The first aim of the study was to investigate the OHC status, contaminant profile, and partitioning of OHCs between muscle and ovary tissue in spawning female char from the high-polluted Lake Ellasjøen and the low-polluted Lake Laksvatn. The second aim was to investigate if OHC levels in muscle tissue have changed over time. Between-lake comparisons show that the muscle levels (lipid weight) of hexachlorobenzene (HCB), chlordanes (∑CHLs), mirex, dichlorodiphenyltrichloroethanes (∑DDTs) and polychlorinated biphenyls (∑PCBs) were up to 36 times higher in char from Ellasjøen than in Laksvatn, and confirm that the char from Ellasjøen are still heavily exposed compared to char from neighboring lake. A higher proportion of persistent OHCs were found in Ellasjøen compared to Laksvatn, while the proportion of the less persistent OHCs was highest in Laksvatn. A between-year comparison of OHC levels (i.e., HCB, DDTs, PCBs) in female and male char shows higher levels of HCB in female char from Ellasjøen in 2009/2012 compared to in 1999/2001. No other between-year differences in OHC levels were found. Due to small study groups, findings associated with between-year differences in OHC levels should be interpreted with caution. OHCs accumulate in the lipid rich ovaries of spawning females, resulting in up to six times higher levels of OHCs in ovaries compared to in muscle (wet weight). The toxic equivalent (TEQ)-value for the dioxin-like PCBs (PCB-105 and -118) in ovaries of the Ellasjøen char exceeded levels associated with increased egg mortality in rainbow trout (Oncorhynchus mykiss). Hence, we suggest that future studies should focus on the reproductive health and performance abilities of the high-exposed population of char inhabiting Lake Ellasjøen. PMID:25864154

  9. A salmonid EST genomic study: genes, duplications, phylogeny and microarrays

    Directory of Open Access Journals (Sweden)

    Brahmbhatt Sonal

    2008-11-01

    Full Text Available Abstract Background Salmonids are of interest because of their relatively recent genome duplication, and their extensive use in wild fisheries and aquaculture. A comprehensive gene list and a comparison of genes in some of the different species provide valuable genomic information for one of the most widely studied groups of fish. Results 298,304 expressed sequence tags (ESTs from Atlantic salmon (69% of the total, 11,664 chinook, 10,813 sockeye, 10,051 brook trout, 10,975 grayling, 8,630 lake whitefish, and 3,624 northern pike ESTs were obtained in this study and have been deposited into the public databases. Contigs were built and putative full-length Atlantic salmon clones have been identified. A database containing ESTs, assemblies, consensus sequences, open reading frames, gene predictions and putative annotation is available. The overall similarity between Atlantic salmon ESTs and those of rainbow trout, chinook, sockeye, brook trout, grayling, lake whitefish, northern pike and rainbow smelt is 93.4, 94.2, 94.6, 94.4, 92.5, 91.7, 89.6, and 86.2% respectively. An analysis of 78 transcript sets show Salmo as a sister group to Oncorhynchus and Salvelinus within Salmoninae, and Thymallinae as a sister group to Salmoninae and Coregoninae within Salmonidae. Extensive gene duplication is consistent with a genome duplication in the common ancestor of salmonids. Using all of the available EST data, a new expanded salmonid cDNA microarray of 32,000 features was created. Cross-species hybridizations to this cDNA microarray indicate that this resource will be useful for studies of all 68 salmonid species. Conclusion An extensive collection and analysis of salmonid RNA putative transcripts indicate that Pacific salmon, Atlantic salmon and charr are 94–96% similar while the more distant whitefish, grayling, pike and smelt are 93, 92, 89 and 86% similar to salmon. The salmonid transcriptome reveals a complex history of gene duplication that is

  10. Clock genes and their genomic distributions in three species of salmonid fishes: Associations with genes regulating sexual maturation and cell cycling

    Directory of Open Access Journals (Sweden)

    Ferguson Moira M

    2010-07-01

    Full Text Available Abstract Background Clock family genes encode transcription factors that regulate clock-controlled genes and thus regulate many physiological mechanisms/processes in a circadian fashion. Clock1 duplicates and copies of Clock3 and NPAS2-like genes were partially characterized (genomic sequencing and mapped using family-based indels/SNPs in rainbow trout (RT(Oncorhynchus mykiss, Arctic charr (AC(Salvelinus alpinus, and Atlantic salmon (AS(Salmo salar mapping panels. Results Clock1 duplicates mapped to linkage groups RT-8/-24, AC-16/-13 and AS-2/-18. Clock3/NPAS2-like genes mapped to RT-9/-20, AC-20/-43, and AS-5. Most of these linkage group regions containing the Clock gene duplicates were derived from the most recent 4R whole genome duplication event specific to the salmonids. These linkage groups contain quantitative trait loci (QTL for life history and growth traits (i.e., reproduction and cell cycling. Comparative synteny analyses with other model teleost species reveal a high degree of conservation for genes in these chromosomal regions suggesting that functionally related or co-regulated genes are clustered in syntenic blocks. For example, anti-müllerian hormone (amh, regulating sexual maturation, and ornithine decarboxylase antizymes (oaz1 and oaz2, regulating cell cycling, are contained within these syntenic blocks. Conclusions Synteny analyses indicate that regions homologous to major life-history QTL regions in salmonids contain many candidate genes that are likely to influence reproduction and cell cycling. The order of these genes is highly conserved across the vertebrate species examined, and as such, these genes may make up a functional cluster of genes that are likely co-regulated. CLOCK, as a transcription factor, is found within this block and therefore has the potential to cis-regulate the processes influenced by these genes. Additionally, clock-controlled genes (CCGs are located in other life-history QTL regions within

  11. Episodic acidification of small streams in the northeastern united states: Fish mortality in field bioassays

    Science.gov (United States)

    Van Sickle, J.; Baker, J.P.; Simonin, H.A.; Baldigo, Barry P.; Kretser, W.A.; Sharpe, W.E.

    1996-01-01

    In situ bioassays were performed as part of the Episodic Response Project, to evaluate the effects of episodic stream acidification on mortality of brook trout (Salvelinus fontinalis) and forage fish species. We report the results of 122 bioassays in 13 streams of the three study regions: the Adirondack mountains of New York, the Catskill mountains of New York, and the Northern Appalachian Plateau of Pennsylvania. Bioassays during acidic episodes had significantly higher mortality than did bioassays conducted under nonacidic conditions, but there was little difference in mortality rates in bioassays experiencing acidic episodes and those experiencing acidic conditions throughout the test period. Multiple logistic regression models were used to relate bioassay mortality rates to summary statistics of time-varying stream chemistry (inorganic monomeric aluminum, calcium, pH, and dissolved organic carbon) estimated for the 20-d bioassay periods. The large suite of candidate regressors also included biological, regional, and seasonal factors, as well as several statistics summarizing various features of aluminum exposure duration and magnitude. Regressor variable selection and model assessment were complicated by multicol-linearity and overdispersion. For the target fish species, brook trout, bioassay mortality was most closely related to time-weighted median inorganic aluminum. Median Ca and minimum pH offered additional explanatory power, as did stream-specific aluminum responses. Due to high multicollinearity, the relative importance of different aluminum exposure duration and magnitude variables was difficult to assess, but these variables taken together added no significant explanatory power to models already containing median aluminum. Between 59 and 79% of the variation in brook trout mortality was explained by models employing between one and five regressors. Simpler models were developed for smaller sets of bioassays that tested slimy and mottled sculpin

  12. Context-specific influence of water temperature on brook trout growth rates in the field

    Science.gov (United States)

    Xu, C.; Letcher, B.H.; Nislow, K.H.

    2010-01-01

    1. Modelling the effects of climate change on freshwater fishes requires robust field-based estimates accounting for interactions among multiple factors.2. We used data from an 8-year individual-based study of a wild brook trout (Salvelinus fontinalis) population to test the influence of water temperature on season-specific growth in the context of variation in other environmental (i.e. season, stream flow) or biotic factors (local brook trout biomass density and fish age and size) in West Brook, a third-order stream in western Massachusetts, U.S.A.3. Changes in ambient temperature influenced individual growth rates. In general, higher temperatures were associated with higher growth rates in winter and spring and lower growth rates in summer and autumn. However, the effect of temperature on growth was strongly context-dependent, differing in both magnitude and direction as a function of season, stream flow and fish biomass density.4. We found that stream flow and temperature had strong and complex interactive effects on trout growth. At the coldest temperatures (in winter), high stream flows were associated with reduced trout growth rates. During spring and autumn and in typical summers (when water temperatures were close to growth optima), higher flows were associated with increased growth rates. In addition, the effect of flow at a given temperature (the flow-temperature interaction) differed among seasons.5. Trout density negatively affected growth rate and had strong interactions with temperature in two of four seasons (i.e. spring and summer) with greater negative effects at high temperatures.6. Our study provided robust, integrative field-based estimates of the effects of temperature on growth rates for a species which serves as a model organism for cold-water adapted ectotherms facing the consequences of environmental change. Results of the study strongly suggest that failure to derive season-specific estimates, or to explicitly consider interactions with

  13. Biological Agents Influencing Physical Process in a Stream: A Case Study in Response to Human-Induced Alteration

    Science.gov (United States)

    Sondossi, H. A.; Bienz, C.

    2013-12-01

    ample depth variability. Water quality has improved to the point that it supports a healthy and expanding population of redband trout alongside introduced eastern brook trout (Salvelinus fontinalis). There have been no sightings of Oregon spotted frog yet, but the habitat is deemed suitable.

  14. Assessment of Native Salmonids Above Hells Canyon Dam, Idaho, 2004-2005 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Kevin A.; Lamansky, Jr., James A. (Idaho Department of Fish and Game, Boise, ID)

    2005-08-01

    In the western United States, exotic brook trout Salvelinus fontinalis frequently have a deleterious effect on native salmonids, and biologists often attempt to remove brook trout in streams using electrofishing. Although the success of electrofishing removal projects typically is low, few studies have assessed the underlying mechanisms of failure, especially in terms of compensatory responses. We evaluated the effectiveness of a three-year removal project in reducing brook trout and enhancing native salmonids in 7.8 km of an Idaho stream and looked for brook trout compensatory responses such as decreased natural mortality, increased growth, increased fecundity at length, or earlier maturation. Due to underestimates of the distribution of brook trout in the first year and personnel shortages in the third year, the multiagency watershed advisory group that performed the project fully treated the stream (i.e. multipass removals over the entire stream) in only one year. In 1998, 1999, and 2000, a total of 1,401, 1,241, and 890 brook trout were removed, respectively. For 1999 and 2000, an estimated 88 and 79% of the total number of brook trout in the stream were removed. For the section of stream that was treated in all years, the abundance of age-1 and older brook trout decreased by 85% from 1998 to 2003. In the same area, the abundance of age-0 brook trout decreased 86% from 1998 to 1999 but by 2003 had rebounded to near the original abundance. Abundance of native redband trout Oncorhynchus mykiss decreased for age-1 and older fish but did not change significantly for age-0 fish. Despite high rates of removal, total annual survival rate for brook trout increased from 0.08 {+-} 0.02 in 1998 to 0.20 {+-} 0.04 in 1999 and 0.21 {+-} 0.04 in 2000. Growth of age-0 brook trout was significantly higher in 2000 (the year after their abundance was lowest) compared to other years, and growth of age-1 and age-2 brook trout was significantly lower following the initial removal

  15. A regional neural network model for predicting mean daily river water temperature

    Science.gov (United States)

    Wagner, Tyler; DeWeber, Jefferson Tyrell

    2014-01-01

    Water temperature is a fundamental property of river habitat and often a key aspect of river resource management, but measurements to characterize thermal regimes are not available for most streams and rivers. As such, we developed an artificial neural network (ANN) ensemble model to predict mean daily water temperature in 197,402 individual stream reaches during the warm season (May–October) throughout the native range of brook trout Salvelinus fontinalis in the eastern U.S. We compared four models with different groups of predictors to determine how well water temperature could be predicted by climatic, landform, and land cover attributes, and used the median prediction from an ensemble of 100 ANNs as our final prediction for each model. The final model included air temperature, landform attributes and forested land cover and predicted mean daily water temperatures with moderate accuracy as determined by root mean squared error (RMSE) at 886 training sites with data from 1980 to 2009 (RMSE = 1.91 °C). Based on validation at 96 sites (RMSE = 1.82) and separately for data from 2010 (RMSE = 1.93), a year with relatively warmer conditions, the model was able to generalize to new stream reaches and years. The most important predictors were mean daily air temperature, prior 7 day mean air temperature, and network catchment area according to sensitivity analyses. Forest land cover at both riparian and catchment extents had relatively weak but clear negative effects. Predicted daily water temperature averaged for the month of July matched expected spatial trends with cooler temperatures in headwaters and at higher elevations and latitudes. Our ANN ensemble is unique in predicting daily temperatures throughout a large region, while other regional efforts have predicted at relatively coarse time steps. The model may prove a useful tool for predicting water temperatures in sampled and unsampled rivers under current conditions and future projections of climate

  16. 基于细胞色素b基因序列分析我国鲑亚科鱼类系统发育关系和不同虹鳟养殖群体遗传变异%Phylogenetic Relationships among Members in Salmoninae and Genetic Variation amongDifferent Populationsof Rainbow Trout Farmedin China Basedon Cytb Sequence

    Institute of Scientific and Technical Information of China (English)

    王伟伟

    2015-01-01

    采用PCR技术扩增了中国不同虹鳟群体的细胞色素b基因,对虹鳟不同养殖群体进行了遗传多样性分析,并与鲑亚科中其他5属11个物种的细胞色素b基因进行同源性比较,建立了主要养殖鲑亚科鱼类的系统关系。试验结果显示,虹鳟种内本地虹鳟群体遗传距离最小(0.001),道氏群体最高(0.004)。种间遗传距离以哲罗鲑与马苏大麻哈鱼的遗传距离最大(0.127),其次为哲罗鲑与银大麻哈鱼(0.123),以远东红点鲑和美洲红点鲑的最近(0.003)。聚类分析表明,同属的鱼均能单独聚类,哲罗鱼属和细鳞鱼属聚在一起,鲑属与红点鲑属聚在一起。虹鳟不同群体间并没有单独聚类,提示不同虹鳟群体间没有发生明显的遗传分化。%The Cytb sequences were amplified by PCR technique ,and genetic diversity was analyzed in different populations of rainbow trout Oncorhynchus mykiss farmed in China . The phylogenetic relationships among members in Salmoninae were established by comparing with the sequences from eleven other species representing five genera in subfamily Salmoninae .The results showed that the local rainbow trout population (0 .001 ) had the minimal intraspecies genetic distance ,and Donaldsons population the maximal (0 .004) .In the interspecies ,however ,there was the maximal genetic distance (0 .127) between taimen Hucho taimen and masou salmon O . masou ,followed by between taimen and coho salmon O . kisutch(0 .123)and the minimal genetic distances between Siberian char Salvelinus leucomaenis and brook trout S .fontinalis (0 .003) .Clustering analysis revealed that fish in the same genus was separately clustered ,lenok Brachymystax and H ucho being clustered together ,and Oncorhynchus and Salvelinus being clustered together .No clustering was observed in the individuals of different rainbow trout populations ,indicating that different populations of rainbow

  17. Phylogenetic Relationships among Members in Salmoninae and Genetic Variation amongDifferent Populationsof Rainbow Trout Farmedin China Basedon Cytb Sequence%基于细胞色素b基因序列分析我国鲑亚科鱼类系统发育关系和不同虹鳟养殖群体遗传变异

    Institute of Scientific and Technical Information of China (English)

    王伟伟

    2015-01-01

    采用PCR技术扩增了中国不同虹鳟群体的细胞色素b基因,对虹鳟不同养殖群体进行了遗传多样性分析,并与鲑亚科中其他5属11个物种的细胞色素b基因进行同源性比较,建立了主要养殖鲑亚科鱼类的系统关系。试验结果显示,虹鳟种内本地虹鳟群体遗传距离最小(0.001),道氏群体最高(0.004)。种间遗传距离以哲罗鲑与马苏大麻哈鱼的遗传距离最大(0.127),其次为哲罗鲑与银大麻哈鱼(0.123),以远东红点鲑和美洲红点鲑的最近(0.003)。聚类分析表明,同属的鱼均能单独聚类,哲罗鱼属和细鳞鱼属聚在一起,鲑属与红点鲑属聚在一起。虹鳟不同群体间并没有单独聚类,提示不同虹鳟群体间没有发生明显的遗传分化。%The Cytb sequences were amplified by PCR technique ,and genetic diversity was analyzed in different populations of rainbow trout Oncorhynchus mykiss farmed in China . The phylogenetic relationships among members in Salmoninae were established by comparing with the sequences from eleven other species representing five genera in subfamily Salmoninae .The results showed that the local rainbow trout population (0 .001 ) had the minimal intraspecies genetic distance ,and Donaldsons population the maximal (0 .004) .In the interspecies ,however ,there was the maximal genetic distance (0 .127) between taimen Hucho taimen and masou salmon O . masou ,followed by between taimen and coho salmon O . kisutch(0 .123)and the minimal genetic distances between Siberian char Salvelinus leucomaenis and brook trout S .fontinalis (0 .003) .Clustering analysis revealed that fish in the same genus was separately clustered ,lenok Brachymystax and H ucho being clustered together ,and Oncorhynchus and Salvelinus being clustered together .No clustering was observed in the individuals of different rainbow trout populations ,indicating that different populations of rainbow

  18. Effets du conditionnement en jours longs à la fin du cycle reproducteur sur la période d'ovulation et sur les sécrétions gonadotropes chez l'omble chevalier (Salvelinus alpinus

    Directory of Open Access Journals (Sweden)

    GILLET C.

    1998-07-01

    Full Text Available Les ombles chevaliers originaires du Léman se reproduisent à la fin de l'automne. En élevage, il est intéressant de retarder de quelques mois la période des ovulations car ce poisson a besoin d'une température inférieure à 6°C pendant l'ovulation. Il est plus facile de fournir une eau à cette température aux géniteurs retardés qui ovulent en hiver qu'à ceux qui ovulent naturellement en automne. Le conditionnement des ombles chevaliers en jours longs (17L-7N pendant l'automne permet de retarder de plusieurs mois la période des ovulations. Cette méthode a l'inconvénient de provoquer un étalement des ovulations sur plus de 3 mois. Le reconditionnement des géniteurs en jours courts en décembre supprime ce problème. L'efficacité du traitement en jours longs ne semble pas dépendre de la durée de son application pourvu que celle-ci dépasse 1,5 mois. Chez les femelles conditionnées en jours longs en automne et en hiver, les concentrations en gonadotropine plasmatique (GTH II sont très faibles. Le niveau de la GTH II plasmatique augmente trois semaines après un transfert en jours courts en janvier. Les concentrations de la GTH II plasmatique au cours de l'ovulation sont significativement plus faibles chez les femelles conditionnées en jours longs en janvier que chez les animaux reconditionnés en jours courts. A ce stade du cycle reproducteur, la GTH I plasmatique reste toujours à un niveau très faible, quel que soit le régime photopériodique. La pose d'implant de mélatonine chez les poissons ne modifie pas les sécrétions gonadotropes en jours longs comme en jours courts. La réceptivité hypophysaire des femelles à une stimulation de la sécrétion gonadotrope par une injection de GnRH n'est pas modifiée par le conditionnement des poissons en jours longs. Aucun effet du pimozide sur la sécrétion de la GTH II n'a pu être mis en évidence chez les géniteurs conditionnés en jours longs. Ces résultats permettent de supposer que l'action inhibitrice des jours longs sur l'ovulation n'est pas la conséquence d'un blocage de type dopaminergique de la sécrétion gonadotrope. Ce type d'inhibition mettrait en oeuvre des mécanismes différents de ceux impliqués dans le blocage de l'ovulation par des températures élevées. L'effet inhibiteur des jours longs à ce stade du cycle reproducteur passe par une diminution de la sécrétion gonadotrope de la GTH II, probablement en relation avec des modifications du contrôle hypothalamique de la sécrétion de la gonadotropine hypophysaire (GTH II.

  19. Knowing for controlling: ecological effects of invasive vertebrates in Tierra del Fuego Conocer para controlar: efectos ecológicos de vertebrados invasores en Tierra del Fuego

    Directory of Open Access Journals (Sweden)

    CLAUDIA A SILVA

    2008-03-01

    Full Text Available The Tierra del Fuego (TDF archipelago is recognized as part o the last places on Earth that may still be considered wild. However, this condition may be threatened by the large number of invasive species present on the archipelago. These species can have significant effects on the ecology of the invaded ecosystems, at the genetic as well as at population, community and ecosystem levels. The aim of this study is to, by a bibliographic review, systematize existing information on the ecological impacts these species would be having on the TDF archipelago and detect information gaps in order to orient future research and effective management programs on these species. We restricted our review to vertebrate, non-marine invaders. We determined which species have invaded TDF, described their impacts on the archipelago and evaluated their potential impacts; this last issue was determined by reviewing some of the impacts these species have had in other geographic areas. Our findings indicate that at least nine vertebrate species (Salmo trutta, Salvelinus fontinalis, Oncorhynchus mykiss, Castor canadensis, Ondatra zibethicus, Oryctolagus cuniculus, Pseudalopex griseus, Mustela vison and Sus seroja have wild populations established away from human settlements in TDF. There is some scientific evidence on ecological impacts on the area for only five of these invaders, with the American beaver (Castor canadensis being the species monopolizing the greatest number of studies. These results contrast with the recognition, both in TDF and worldwide, of the potential of most of these species to cause significant ecological impacts, which makes it unlikely that the lack of verified impacts on TDF reflects an absence of significant effects of these invaders on the archipelago. We suggest that future research should focus on determining population density and distribution of these and other (i.e., feral species invasive vertebrates, as well as their impacts mainly on

  20. Cloning and Tissue Expression Analysis ofPAX7 Gene in Grass Carp (Ctenopharyngodon idellus)%草鱼PAX7基因的克隆、序列分析及组织表达

    Institute of Scientific and Technical Information of China (English)

    甘甜; 冷向军; 郭婷; 胡静; 魏静; 李小勤

    2014-01-01

    Paired box gene 7(PAX7)is crucially important to the cellular renewal, differentiation and apoptosis, especially in neural crest development, gastrulation, and muscle self-renewal. ThePAX7 domains sequence is conserved among several species, such as zebrafish, apteronotidae, and rainbow trout, and the conserved sequence zebrafish was used to design degenerate primers for reverse-transcription PCR(RT-PCR). A partial sequence ofPAX7 from grass carp was obtained for a 645 bp segment encoding a 214 amino acid peptide, containing a paired box domain with 128 amino acids. The deduced protein showed homology to zebrafish(Danio rerio), apteronotidae(Sternopygus macrurus), Japanese Medaka(Oryzias latipes), gilthead bream(Sparus aurata), rainbow trout(Oncorhynchus mykiss), Atlantic salmon(Salmo salar), Arctic charr(Salvelinus alpinus), human(Homo sapiens), wild yak(Bos grunniens mutus), brown rat(Rattus norvegicus), and mouse(Mus musculus)with 90%-97% identities. Analysis of the PAX7 phylogenetic tree revealed that the grass carp joined with zebrafish, and there was a confluence of Japanese medaka, Arctic charr, Atlantic salmon, rainbow trout, apteronotidae and gilthead bream. The other branch was consisted of mouse, brown rat, wild yak and human. These results conformed to the traditional species classification evolution status. The expression in tissues was detected by Real-time quantitative PCR, which indicated that the highest level ofPAX7 gene expression was found in muscle, a lower expression level was found in foregut and skin, and the lowest detectable level was found in heart, brain, kidney and liver. The results are in agreement with the function of the gene.%配对盒基因7(Paired box 7 gene,PAX7)在神经嵴发育及原肠胚形成、肌肉自主更新与再生中扮演着重要角色,对细胞更新、分化、凋亡等起着十分重要的调控作用。参照GenBank中斑马鱼、线鳍电鳗和虹鳟等物种PAX7序列的保守区域设计简并引

  1. Centralizing Automorphisms of Lie Ideals in Prime Rings of Characteristic 2

    Institute of Scientific and Technical Information of China (English)

    王宇; 段学新

    2005-01-01

    Let R be a prime ring with an automorphism σ≠1, an identity map. Let L be a noncentral Lie ideal of R such that [xσ,x] E Z for all x ∈ L, where Z is the center of R. Then L is contained in the center of R, unless char(R)=2 and dimc RC = 4.

  2. Acid rain publications by the U.S. Fish and Wildlife Service, 1979-1989

    Science.gov (United States)

    Villella, Rita F.

    1989-01-01

    Pollution of aquatic and terrestrial ecosystems has been a concern to society since the burning of fossil fuels began in the industrial revolution. In the past decade or so, this concern has been heightened by evidence that chemical transformation in the atmosphere of combustion by-products and subsequent long-range transport can cause environmental damage in remote areas. The extent of this damage and the rates of ecological recovery were largely unknown. "Acid rain" became the environmental issue of the 1980's. To address the increasing concerns of the public, in 1980 the Federal government initiated a 10-year interagency research program to develop information that could be used by the President and the Congress in making decisions for emission controls. The U.S. Fish and Wildlife Service has been an active participant in acid precipitation research. The Service provided support to a number of scientific conferences and forums, including the Action Seminar on Acid Precipitation held in Toronto, Canada, in 1979, an international symposium on Acidic Precipitation and Fishery Impacts in Northeastern North America in 1981, and a symposium on Acidic Precipitation and Atmospheric Deposition: A Western Perspective in 1982. These meetings as well as the growing involvement with the government's National Acidic Precipitation Assessment Program placed the Service in the lead in research on the biological effects of acidic deposition. Research projects have encompassed water chemistry, aquatic invertebrates, amphibians, fish, and waterfowl. Water quality surveys have been conducted to help determine the extent of acid precipitation effects in the northeast, Middle Atlantic, and Rocky Mountain regions. In addition to lake and stream studies, research in wetland and some terrestrial habitats has also been conducted. Specific projects have addressed important sport species such as brook trout (Salvelinus fontinalis), Atlantic salmon (Salmo salar), and striped bass (Morone

  3. Synthesis and interpretation of surface-water quality and aquatic biota data collected in Shenandoah National Park, Virginia, 1979-2009

    Science.gov (United States)

    Jastram, John D.; Snyder, Craig D.; Hitt, Nathaniel P.; Rice, Karen C.

    2013-01-01

    ABSTRACT Shenandoah National Park in northern and central Virginia protects 777 square kilometers of mountain terrain in the Blue Ridge physiographic province and more than 90 streams containing diverse aquatic biota. Park managers and visitors are interested in the water quality of park streams and its ability to support healthy coldwater communities and species, such as the native brook trout (Salvelinus fontinalis), that are at risk in the eastern United States. Despite protection from local stressors, however, the water quality of streams in the park is at risk from many regional stressors, including atmospheric pollution, decline in the health of the surrounding forests because of invasive forest pests, and global climate change. In 2010, the U.S. Geological Survey, in cooperation with the National Park Service, undertook a study to compile, analyze, and synthesize available data on water quality, aquatic macroinvertebrates, and fish within Shenandoah National Park. Specifically, the effort focused on creating a comprehensive water-resources database for the park that can be used to evaluate temporal trends and spatial patterns in the available data, and characterizing those data to better understand interrelations among water quality, aquatic macroinvertebrates, fish, and the landscape. Data from three primary sources, namely the Shenandoah Watershed Study, the Shenandoah National Park Aquatic Macroinvertebrate Monitoring Program, and the Springs and Headwater Streams Study, were compiled and loaded into the National Park Service’s NPSTORET database. This effort yielded a comprehensive database containing nearly 1.3 million measurements of habitat characteristics, approximately 442,000 measurements of water-quality characteristics, and over 438,000 measurements of biological taxa (fish and aquatic macroinvertebrates), collected across 673 sites over a period of more than 30 years. Temporal trends in water quality indicate conflicting patterns in terms of

  4. Assessment of Native Salmonids Above Hells Canyon Dam, Idaho, 2003-2004 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Kevin A.; Lamansky, Jr., James A. (Idaho Department of Fish and Game, Boise, ID)

    2004-08-01

    Despite the substantial declines in distribution and abundance that the Yellowstone cutthroat trout Oncorhynchus clarkii bouvieri has experienced over the past century, quantitative evaluations of existing population sizes over broad portions of its historical range have not been made. In this study, we estimate trout abundance throughout the Upper Snake River basin in Idaho (and portions of adjacent states), based on stratified sample extrapolations of electrofishing surveys conducted at 961 study sites, the vast majority of which (84%) were selected randomly. Yellowstone cutthroat trout were the most widely distributed species of trout (caught at 457 study sites), followed by brook trout Salvelinus fontinalis (242 sites), rainbow trout O. mykiss and rainbow x cutthroat hybrids (136 sites), and brown trout Salmo trutta (70 sites). Of the sites that contained cutthroat trout, more than half did not contain any other species of trout. Where nonnative trout were sympatric with cutthroat trout, brook trout were most commonly present. In the 11 Geographic Management Units (GMUs) where sample size permitted abundance estimates, there were about 2.2 million trout {ge}100 mm, and of these, about one-half were cutthroat trout. Similarly, we estimated that about 2.0 million trout <100 mm were present, of which about 1.2 million were cutthroat trout. The latter estimate is biased low because our inability to estimate abundance of trout <100 mm in larger-order rivers negated our ability to account for them at all. Cutthroat trout were divided into approximately 70 subpopulations but estimates could be made for only 55 subpopulations; of these, 44 subpopulations contained more than 1,000 cutthroat trout and 28 contained more than 2,500 cutthroat trout. Using a logistic regression model to predict the number of spawning cutthroat trout at a given study site, we estimate that an average of about 30% of the cutthroat trout {ge}100 mm are spawners. We compared visually

  5. What are the toxicological effects of mercury in Arctic biota?

    DEFF Research Database (Denmark)

    Dietz, Rune; Sonne, Christian; Basu, Niladri;

    2013-01-01

    effects. Species whose concentrations exceed threshold values include the polar bears (Ursus maritimus), beluga whale (Delphinapterus leucas), pilot whale (Globicephala melas), hooded seal (Cystophora cristata), a few seabird species, and landlocked Arctic char (Salvelinus alpinus). Toothed whales appear...

  6. Migration studies and stock structure of dolly varden in the Chiniak Bay area of Kodiak Island, Alaska: Draft

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — From 1984 through 1989 a total of 31,374 Dolly Varden (Salvelinus malma) in the Chiniak Bay area of Kodiak Island, Alaska were tagged with numbered anchor tags....

  7. The Gastropods of Lake Eğirdir

    OpenAIRE

    YILDIRIM, Mehmet Zeki

    2004-01-01

    The Gastropoda species and its distribution was investigated in Lake Eğirdir. It was determined that 5 species belonging to Gastropoda, order Prosobranchia (Theodoxus heldreichi, Valvata naticina, Graecoanatolica lacustristurca, Falsipyrgula pfeiferi and Bithynia pseudemmericia) and 7 species belonging to the order Pulmonata (Radix peregra, Stagnicola palustris, Physa fontinalis, Physa acuta, Planorbis planorbis, Planorbis carinatus and Gyraulus albus) were present. Gastropoda species from 9 ...

  8. Centralizing Automorphisms of Lie Ideals in Prime Rings of Characteristic 2%特征为2的素环的Lie理想上中心化自同构

    Institute of Scientific and Technical Information of China (English)

    王宇; 段学新

    2005-01-01

    Let R be a prime ring with an automorphism σ≠ 1, an identity map.Let L be a noncentral Lie ideal of R such that [xσ, x] ∈ Z for all x ∈ L, where Z is the center of R. Then L is contained in the center of R, unless char(R) = 2 and dimCRC=4.

  9. Effects of lake warming on behavioural thermoregulatory tactics in a cold-water stenothermic fish.

    Directory of Open Access Journals (Sweden)

    Katerine Goyer

    Full Text Available Despite some evidence of within-population phenotypic variation in fish thermal behaviour, the occurrence of alternative tactics of this behaviour is rarely explicitly considered when studying natural populations. Brook charr provide an example of within-population variability in behavioural thermoregulation as revealed by a recent study on a lacustrine population of this species. The objectives of the present study were (i to determine the influence of natural variability in the lake's thermal profiles on the expression of thermoregulatory tactics, and (ii to determine the vertical and horizontal movements of individuals at different periods of the day to better understand the spatio-temporal behaviour associated with each thermoregulatory tactic. During summer 2010, 30 adult brook charr were equipped with thermo-sensitive radio transmitters to monitor their selected temperatures and daily movements. These individuals exhibited the same four behavioural thermoregulatory tactics observed in 2003 and 2005, but the expression of two of these was weaker in 2010. This result was associated with lake warming, which constrained the expression of two thermoregulatory tactics: brook charr significantly decreased their selected temperatures and daily movements when the mean daily epilimnion temperature was above 22.4°C. This study shows for the first time that the expression of behavioural thermoregulatory tactics is related to the lake's thermal regime and that the tactics are plastic through time.

  10. Aquatic biological communities and associated habitats at selected sites in the Big Wood River Watershed, south-central Idaho, 2014

    Science.gov (United States)

    MacCoy, Dorene E.; Short, Terry M.

    2016-09-28

    limited at BW Stanton, where shallow-water habitat conditions prevailed.Macroinvertebrate community diversity was high at all sites except for BW Stanton, where low community diversity was attributed to low species richness and high abundances of a few tolerant taxa. Presence of low species diversity and high macroinvertebrate tolerance values at BW Stanton indicates that benthic community condition and stream health were reduced at that location.Fish surveys done in September 2014 did not indicate any significant reductions in native fish communities in the Big Wood River or its tributaries. Native rainbow trout (Oncorhynchus mykiss) and Wood River sculpin (Cottus leiopomus) were the dominant fish species in the drainage and were found at all tributary and main-stem sites. Non-native brown (Salmo trutta) and brook trout (Salvelinus fontinalis) were limited to lower drainage sites on the Big Wood River (BW Hailey and BW Stanton), and occurred in relatively low numbers.

  11. Methods for processing aquatic mosses used as monitors of heavy metals

    Energy Technology Data Exchange (ETDEWEB)

    Wehr, J.D.; Empain, A.; Mouvet, C.; Say, P.J.; Whitton, B.A.

    1983-01-01

    An evaluation is reported of methods used to prepare mosses for analysis when required for monitoring metal pollution. Fontinalis antipyretica and Rhynchostegium riparioides taken from the River Hoegne, Belgium, were used for the study. The stages in preparation studied critically were the storage of the moss after it had been collected from the river, washing, choice of which particular fraction to use and the conditions for final drying prior to digestion. For any one particular treatment, the concentrations of metals analysed (Ca, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb) were usually lower in Fontinalis than Rhynchostegium. Metal concentrations found as a result of the various treatments differed markedly for some metals, including Zn, Cd and Pb. However not one sequence of methods is ideal for all purposes. Criteria that need to be considered when selecting methods include the time and facilities available and whether the moss is to be used for monitoring long-term or short-term pollution.

  12. Los pronombres demostrativos de la lengua chaná (Entre Ríos, Argentina)

    OpenAIRE

    Viegas Barros, J. Pedro

    2012-01-01

    La categoría de los pronombres demostrativos es universal en las lenguas naturales, pero las características funcionales, formales, sintácticas y pragmáticas de estos elementos varían considerablemente de una a otra lengua. El propósito de este trabajo es describir las características funcionales, formales, sintácticas y pragmáticas de los demostrativos en la lengua indígena obsolescente chaná, perteneciente a la familia charrúa, que cuenta actualmente con un último semi-hablante terminal res...

  13. The rhesus monkey (Macaca mulatta) as a flight candidate

    Science.gov (United States)

    Debourne, M. N. G.; Bourne, G. H.; Mcclure, H. M.

    1977-01-01

    The intelligence and ruggedness of rhesus monkeys, as well as the abundance of normative data on their anatomy, physiology, and biochemistry, and the availability of captive bred animals qualify them for selection as candidates for orbital flight and weightlessness studies. Baseline data discussed include: physical characteristics, auditory thresholds, visual accuity, blood, serological taxomony, immunogenetics, cytogenics, circadian rhythms, respiration, cardiovascular values, corticosteroid response to charr restraint, microscopy of tissues, pathology, nutrition, and learning skills. Results from various tests used to establish the baseline data are presented in tables.

  14. Kalispel Resident Fish Project, 2004-2005 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Olson, Jason; Andersen, Todd

    2005-06-01

    In 2004 the Kalispel Natural Resource Department (KNRD) implemented a new enhancement monitoring project for bull trout (Salvelinus confluentus) and westslope cutthroat trout (Oncorhynchus clarki lewisi). Largemouth bass (Micropterus salmoides) enhancement projects were also monitored. Additional baseline fish population and habitat assessments were conducted, in tributaries to the Pend Oreille River.

  15. Kalispel Resident Fish Project, 2005-2006 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Olson, Jason; Andersen, Todd (Kalispel Natural Resource Department, Usk, WA)

    2006-07-01

    In 2005 the Kalispel Natural Resource Department (KNRD) monitored its current enhancement projects for bull trout (Salvelinus confluentus) and westslope cutthroat trout (Oncorhynchus clarki lewisi). Largemouth Bass (Micropterus salmoides) enhancement projects were also monitored. Additional baseline fish population and habitat assessments were conducted, in East River and several of its tributaries.

  16. Kalispel Resident Fish Project : Annual Report, 2002.

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, Todd; Olson, Jason

    2003-03-01

    In 2002 the Kalispel Natural Resource Department (KNRD) continued monitoring enhancement projects (implemented from 1996 to 1998) for bull trout (Salvelinus confluentus), westslope cutthroat (Oncorhynchus clarki lewisi) and largemouth bass (Micropterus salmoides). Additional baseline fish population and habitat assessments were conducted, in 2002, in tributaries to the Pend Oreille River. Further habitat and fish population enhancement projects were also implemented in 2002.

  17. Salmon returns and consumer fitness: growth and energy storage in stream-dwelling salmonids increases with spawning salmon abundance

    Science.gov (United States)

    We examined how biomass of marine-derived nutrients (MDN), in the form of spawning Pacific salmon, influenced the nutritional status and nitrogen stable isotope ratios (d15N) of stream-dwelling fishes. We sampled coho salmon (Oncorhynchus kisutch) parr and juvenile Dolly Varden (Salvelinus malma) d...

  18. An Engel Condition with Derivation for Multilinear Polynomials in Prime Rings

    Institute of Scientific and Technical Information of China (English)

    Vincenzo De Filippis; Onofrio Mario Di Vincenzo

    2002-01-01

    Let R be a prime algebra without non-zero nil right ideals over a commutative ring K, f(x1,..., xn) a multilinear polynomial in n variables over K, and d a non-zero derivation of R such that for any r1,..., rn ∈ R, there exists k = k(r1, ... ,rn)≥1 such that [d(f(r1,...,rn)),f(r1,... ,rn)]k = 0. If char(R)= 0, then f(x1,..., xn) is a polynomial central-valued on R. If char(R) = p > 2and f(x1,..., xn) is not a polynomial identity in p × p matrices of characteristic p, then R satisfies Sn+2(x1,... ,xn+2), and for any r1,... ,rn ∈ R, there exists t = t(r1,...,rn) ≥1 such that fpt (r1,...,rn) ∈ Z(R). Moreover, if Z(R) is finite, then f(x1,...., xn) is central-valued on R.

  19. Synthesis and interpretation of surface-water quality and aquatic biota data collected in Shenandoah National Park, Virginia, 1979-2009

    Science.gov (United States)

    Jastram, John D.; Snyder, Craig D.; Hitt, Nathaniel P.; Rice, Karen C.

    2013-01-01

    ABSTRACT Shenandoah National Park in northern and central Virginia protects 777 square kilometers of mountain terrain in the Blue Ridge physiographic province and more than 90 streams containing diverse aquatic biota. Park managers and visitors are interested in the water quality of park streams and its ability to support healthy coldwater communities and species, such as the native brook trout (Salvelinus fontinalis), that are at risk in the eastern United States. Despite protection from local stressors, however, the water quality of streams in the park is at risk from many regional stressors, including atmospheric pollution, decline in the health of the surrounding forests because of invasive forest pests, and global climate change. In 2010, the U.S. Geological Survey, in cooperation with the National Park Service, undertook a study to compile, analyze, and synthesize available data on water quality, aquatic macroinvertebrates, and fish within Shenandoah National Park. Specifically, the effort focused on creating a comprehensive water-resources database for the park that can be used to evaluate temporal trends and spatial patterns in the available data, and characterizing those data to better understand interrelations among water quality, aquatic macroinvertebrates, fish, and the landscape. Data from three primary sources, namely the Shenandoah Watershed Study, the Shenandoah National Park Aquatic Macroinvertebrate Monitoring Program, and the Springs and Headwater Streams Study, were compiled and loaded into the National Park Service’s NPSTORET database. This effort yielded a comprehensive database containing nearly 1.3 million measurements of habitat characteristics, approximately 442,000 measurements of water-quality characteristics, and over 438,000 measurements of biological taxa (fish and aquatic macroinvertebrates), collected across 673 sites over a period of more than 30 years. Temporal trends in water quality indicate conflicting patterns in terms of

  20. Aporte indígena a la población uruguaya: ¿Charruas o Guaranies?

    Directory of Open Access Journals (Sweden)

    Sans, Mónica

    2005-01-01

    Full Text Available Durante el siglo XIX, las reiteradas matanzas da indígenas llevaron a forjar la identidad de los uruguayos como de "país de inmigrantes", sin continuidad entre los habitantes históricos y los actuales. Sin embargo, diversos historiadores plantean un aparte de varios miles de guaraníes, mientras que Re hace referencia al reparto da algunos cientos de mujeres y niños charrúas. Ej la década de 1980, el análisis de marcadores genéticos mostró contribución indígena a la población en distintas regiones del país, y posteriormente, que este aporte era mayor al considerar linajes maternos. Para investigar el origen de estas indígenas, y la posible continuidad genética desde tiempos prehistóricos, se analiza ADNmt de habitantes prehistóricos, históricos y actuales dal territorio uruguayo. Se compara la frecuencia de los haplogrupos indígenas y secuencias de la región hiparvariable I de población actual (con 7 individuos inhumados en "cerritos", un charrúa histórico, y grupos indígenas de América del Sur. La población uruguaya presenta mayoría de haplogrupos B y C (ambos 35, al igual que los sitios prehistóricos. Estos dos haplogrupos son comunes en Patagonia, mientras qua los guaraníes carecen casi totalmente del C, lo cual podría indicar un mayor aporte pampeano-Patagónico (macro-etnia charrúa que guaraní, contrariamente a lo esperado. Además, se pudo establecer continuidad poblacional desde la prehistoria, marcada por la presencia de una mutación rara asociada ah haplogrupo C (Transición en 1688.

  1. Differences between white and red muscle fibers diameter in three salmon fish species

    OpenAIRE

    Karahmet E.; Vileš A.; Katica A.; Mlaćo N.; Toroman A.

    2014-01-01

    Because of skeletal muscle is the main contributor to body weight in most fish, it is probable that the species of the fish is limited by the growth of this tissue. Several aspects of both somatic size and skeletal muscle growth was investigated in this research work included a total of 20 brown trout (Salmo truta m. fario Lineus), 20 brook trout (Salvelinus alpinus) and 20 rainbow trout (Oncorynchus mykkis Walbaum), the average weight of 200 grams. Gathere...

  2. Kalispel Resident Fish Project : Annual Report, 2001.

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, Todd

    2002-01-01

    In 2001 the Kalispel Natural Resource Department (KNRD) continued assessing habitat and population enhancement projects for bull trout (Salvelinus confluentus), westslope cutthroat (Oncorhynchus clarki lewisi) and largemouth bass (Micropterus salmoides). Habitat enhancement measures, as outlined in recommendations from the 1996, 1997, and 1998 annual reports, were monitored during field season 1999, 2000, and 2001. Post assessments were used to evaluate habitat quality, stream morphology and fish populations where enhancement projects were implemented.

  3. First evidence of successful natural reproduction by planted lake trout in Lake Huron

    Science.gov (United States)

    Nester, Robert T.; Poe, Thomas P.

    1984-01-01

    Twenty-two lake trout (Salvelinus namaycush) swim-up fry, 24-27 mm long, were captured with emergent fry traps and a tow net in northwestern Lake Huron on a small nearshore reef off Alpena, Michigan, between May 10 and June 1, 1982. These catches represent the first evidence of successful production of swim-up fry by planted, hatchery-reared lake trout in Lake Huron since the lake trout rehabilitation program began in 1973.

  4. A review of fish lectins.

    Science.gov (United States)

    Ng, Tzi Bun; Fai Cheung, Randy Chi; Wing Ng, Charlene Cheuk; Fang, Evandro Fei; Wong, Jack Ho

    2015-01-01

    Lectins have been reported from various tissues of a diversity of fish species including Japanese eel, conger eel, electric eel, bighead carp, gibel carp, grass carp, Arabian Gulf catfish, channel catfish, blue catfish, catfish, pike perch, perch, powan, zebrafish, toxic moray, cobia fish, steelhead trout, Japanese trout, Atlantic salmon, chinook salmon, olive rainbow smelt, rainbow smelt, white-spotted charr, tilapia, blue gourami, ayu, Potca fish, Spanish mackerel, gilt head bream, tench, roach, rudd, common skate, and sea lamprey. The tissues from which the lectins were isolated comprise gills, eggs, electric organ, stomach, intestine, and liver. Lectins have also been isolated from skin, mucus serum, and plasma. The lectins differ in molecular weight, number of subunits, glycosylation, sugar binding specificity and amino acid sequence. Their activities include antimicrobial, antitumor, immunoregulatory and a role in development. PMID:25929869

  5. Study for the determination of samarium, europium,terbium, dysprosium and yttrium in gadolinium oxide matrix by means of atomic absorption spectrophotometry using a graphite furnace

    International Nuclear Information System (INIS)

    A study for determination of samarium, europium, terbium, dysprosium and yttrium in a gadolinium oxide matrix by atomic absorption spectrophotometry using a graphite furnace is presented. The best charrring and atomization conditions were estabilished for each element, the most convenient ressonance lines being selected as well. The study was carried out for the mentioned lanthanides both when pure and when in binary mixtures with gadolinium, besides those where all for them were together with gadolinium. The determination limits for pure lanthanides were found to be between 1.3 and 9.6 ng assuming a 20% relative standard deviation as acceptable. The detection limits were in the range 0.51 and 7.5 ng, assuming as positive any answer higher than twofold the standard deviation. (author)

  6. Distribution of uranium, americium and plutonium in the biomass of freshwater macrophytes

    Energy Technology Data Exchange (ETDEWEB)

    Zotina, T.A.; Kalacheva, G.S.; Bolsunovsky, A.YA. [Institute of Biophysics SB RAS, Akademgorodok, Krasnoyarsk (Russian Federation)

    2010-07-01

    Accumulation of uranium ({sup 238}U), americium ({sup 241}Am) and plutonium ({sup 242}Pu) and their distribution in cell compartments and biochemical components of the biomass of aquatic plants Elodea canadensis, Ceratophyllum demersum, Myrioplyllum spicatum and aquatic moss Fontinalis antipyretica have been investigated in laboratory batch experiments. Isotopes of uranium, americium and plutonium taken up from the water by Elodea canadensis apical shoots were mainly absorbed by cell walls, plasmalemma and organelles. A small portion of isotopes (about 6-13 %) could be dissolved in cytoplasm. The major portion (76-92 %) of americium was bound to cell wall cellulose-like polysaccharides of Elodea canadensis, Myriophyllum spicatum, Ceratophyllum demersum and Fontinalis antipyretica, 8-23 % of americium activity was registered in the fraction of proteins and carbohydrates, and just a small portion (< 1%) in lipid fraction. The distribution of plutonium in the biomass fraction of Elodea was similar to that of americium. Hence, americium and plutonium had the highest affinity to cellulose-like polysaccharides in Elodea biomass. Distribution of uranium in the biomass of Elodea differed essentially from that of transuranium elements: a considerable portion of uranium was recorded in the fraction of protein and carbohydrates (51 %). From our data we can assume that uranium has higher affinity to carbohydrates than proteins. (authors)

  7. Kinetic modelling of cadmium and lead removal by aquatic mosses

    Directory of Open Access Journals (Sweden)

    R. J. E. Martins

    2014-03-01

    Full Text Available Because biosorption is a low cost and effective method for treating metal-bearing wastewaters, understanding the process kinetics is relevant for design purposes. In the present study, the performance of the aquatic moss Fontinalis antipyretica for removing cadmium and lead from simulated wastewaters has been evaluated. Five kinetic models (first-order, pseudo-first-order, Elovich, modified Ritchie second-order and pseudo-second-order were fitted to the experimental data and compared. Previously, the effect of parameters such as the initial solution pH, contact time, and initial metal ion concentration on biosorption was investigated. The initial pH of the solution was found to have an optimum value in the range of 4.0-6.0. The equilibrium sorption capacity of cadmium and lead by Fontinalis antipyretica increased with the initial metal concentration. For an initial metal concentration of 10 mg L-1, the uptake capacity of the moss, at equilibrium, is the same for both metals (4.8 mg g-1. Nevertheless, when the initial concentration increases up to 100 mg L-1, the uptake of Pb(II was higher than 78%. The pseudo-second order biosorption kinetics provided the better correlation with the experimental data (R² ≥ 0.999.

  8. Radioactive contamination of aquatic organisms of the Yenisei river in the area affected by the activity of a Russian plutonium complex

    International Nuclear Information System (INIS)

    The Yenisei River, one of the world's largest rivers, is contaminated with artificial radionuclides released by a Russian facility producing weapons-grade plutonium, which has been in operation for many years. The aim of the study conducted between 1997 and 2003 was to investigate accumulation of artificial radionuclides by aquatic organisms of the Yenisei River and to estimate the exposure dose rates to organisms from various sources. The aquatic plants sampled were of three species: Potamogeton lucens, Fontinalis antipyretica, and Ceratophyllum demersum. The gamma-spectrometric and radiochemical analysis of the samples of aquatic plants for artificial radionuclides has revealed more than 20 long-lived and short-lived radionuclides, including plutonium isotopes. The aquatic animal Phylolimnogammarus viridis and diatoms also contain artificial radionuclides. For most aquatic organisms under study, the dose received from the artificial irradiation is an order of magnitude higher than the dose received from natural irradiation. As Fontinalis antipyretica features the highest capacity to accumulate artificial radionuclides, it accumulates the largest artificial exposure does among the study aquatic organisms (up to 39 μGy/day)

  9. Background concentrations of heavy metals in aquatic bryophytes used for biomonitoring in basaltic areas (a case study from central France)

    Energy Technology Data Exchange (ETDEWEB)

    Samecka-Cymerman, A. [Wroclaw Univ. (Poland). Dept. of Ecology and Nature Protection; Kempers, A.J. [Nijmegen Univ. (Netherlands). Dept. of Aquatic Ecology and Biogeology

    1999-12-01

    Studies were made of the aquatic bryophytes Fontinalis antipyretica Hedw., Plathypnidium rusciforme (Neck.)Fleisch and Chiloscyphus sp. (Hoffm.)Dum. from streams embedded in basaltic rocks (Le Puy, central France). Water from these streams possessed elevated levels of Cu, Zn, Sr, V, Ba, Ni and Co, reflecting the geochemistry of the basalts, a basic type of igneous rocks containing elevated levels of these elements. The concentration of elements in bryophytes is correlated to the chemical composition of water of their sampling sites. Contents of trace elements in plants were higher than background values. The elevated levels of these elements possibly caused disturbances in the ionic equilibrium within the bryophytes. The molar ratio between contents of Ca and Mg in water (from 0.44 to 1) was different from that typical for natural water. (orig.)

  10. Uptake of uranium by native aquatic plants: potential for bioindication and phytoremediation

    Directory of Open Access Journals (Sweden)

    Favas P. J. C.

    2013-04-01

    Full Text Available The work presented here is a part the on going study on the uraniferous geochemical province of Central Portugal in which, the use of aquatic plants as indicators of uranium contamination is being probed using aquatic plants emphasizing their potential use in the emerging phytotechnologies. Even though we have observed very low concentration of U in the fresh waters of the studied sites we found a set of vegetable species with the ability to accumulate U in concentrations which are orders of magnitude higher than the surrounding environment. We have observed that Apium nodiflorum, Callitriche stagnalis, Lemna minor and Fontinalis antipyretica accumulated significant amounts of uranium, whereas Oenanthe crocata excluded U. These results indicate substantial scope for proper radiophytoremediation and phytosociological investigation exploiting the native flora. These species show great potential for phytoremediation because they are endemic and easy to grow in their native conditions. A. nodiflorum and C. stagnalis have high bioproductivity and yield good biomass.

  11. The fate of mercury in Arctic terrestrial and aquatic ecosystems, a review

    DEFF Research Database (Denmark)

    Douglas, Thomas A.; Loseto, Lisa L.; MacDonald, Robie W.;

    2012-01-01

    into the Arctic by oceanic, atmospheric and terrestrial pathways. Our focus is on the movement, transformation and bioaccumulation of Hg in aquatic (marine and fresh water) and terrestrial ecosystems. The processes most relevant to biological Hg uptake and the potential risk associated with Hg exposure...... the fate of Hg in most ecosystems, and the role of trophic processes in controlling Hg in higher order animals are also included. Case studies on Eastern Beaufort Sea beluga (Delphinapterus leucas) and landlocked Arctic char (Salvelinus alpinus) are presented as examples of the relationship between...

  12. Hungry Horse Dam Fisheries Mitigation; Kokanee Stocking and Monitoring in Flathead Lake, 1995 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Fredenberg, Wade; Carty, Daniel (US Fish and Wildlife Service, Kalispell, MT); Cavigli, Jon (Montana Department of Fish, Wildlife and Parks, Kalispell, MT)

    1996-06-01

    The operation of Hungry Horse Dam on the South Fork-of the Flathead River reduced the reproductive success of kokanee (Oncorhynchus nerka) spawning in the Flathead River. Montana Fish, Wildlife and Parks (MFWP) and the Confederated Salish and Kootenai Tribes (CSKT) authored a mitigation plan to offset those losses. The mitigation goal, stated in the Fisheries Mitigation Plan for Losses Attributed to the Construction and Operation of Hungry Horse Dam, is to: {open_quotes}Replace lost annual production of 100,000 kokanee adults, initially through hatchery production and pen rearing in Flathead Lake, partially replacing lost forage for lake trout (Salvelinus namaycush) in Flathead Lake.{close_quotes}

  13. Kalispel Resident Fish Project : Annual Report, 2008.

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, Todd [Kalispel Natural Resource Department

    2009-07-08

    In 2008, the Kalispel Natural Resource Department (KNRD) continued to implement its habitat enhancement projects for bull trout (Salvelinus confluentus) and westslope cutthroat trout (Oncorhynchus clarki lewisi). Baseline fish population and habitat assessments were conducted in Upper West Branch Priest River. Additional fish and habitat data were collected for the Granite Creek Watershed Assessment, a cooperative project between KNRD and the U.S. Forest Service Panhandle National Forest (FS) . The watershed assessment, funded primarily by the Salmon Recovery Funding Board of the State of Washington, will be completed in 2009.

  14. Behavioral evidence for a role of chemoreception during reproduction in lake trout

    Science.gov (United States)

    Buchinger, Tyler J.; Li, Weiming; Johnson, Nicholas

    2015-01-01

    Chemoreception is hypothesized to influence spawning site selection, mate search, and synchronization of gamete release in chars (Salvelinus spp.), but behavioral evidence is generally lacking. Here, we provide a survey of the behavioral responses of reproductive male and female lake trout (Salvelinus namaycush) to natural conspecific chemosensory stimuli. A flow-through laboratory assay with side-by-side artificial spawning reefs was used to evaluate behavioral preferences of spawning-phase males and females for chemosensory stimuli from juveniles and from spawning-phase males and females. Males and females preferred male and juvenile stimuli over no stimuli, but only had weak preferences for female stimuli. Only females had a preference for male over juvenile stimuli when given a direct choice between the two. The unexpected observation of male attraction to male stimuli, even when offered female stimuli, indicates a fundamental difference from the existing models of chemical communication in fishes. We discuss our results from the perspectives of prespawning aggregation, mate evaluation, and spawning synchronization. Identification of specific components of the stimuli will allow confirmation of the function and may have management implications for native and invasive populations of lake trout that are ecologically and economically important.

  15. A comparison of contaminant dynamics in arctic and temperate fish: A modeling approach.

    Science.gov (United States)

    Gewurtz, Sarah B; Laposa, Rebecca; Gandhi, Nilima; Christensen, Guttorm N; Evenset, Anita; Gregor, Dennis; Diamond, Miriam L

    2006-05-01

    In order to compare the abilities of arctic and temperate fish to accumulate PCBs we conduct a metabolic analysis to determine how process rates in a mathematical fish contaminant model change with temperature. We evaluate the model by applying the original and adapted models to estimate PCB concentrations in lake trout (Salvelinus namaycush) in Trout Lake, Ontario, Canada, and in arctic char (Salvelinus alphinus) in Lake Øyangen, in the Norwegian high arctic. Modeled concentrations are, for the most part, within 50% of mean measured values and are comparable to the error associated with the fish data. In order to evaluate differences in fish bioaccumulation processes, the model is applied to hypothetical arctic and temperate systems, assuming the same contaminant input values in water and diet. The model predicts that temperate salmonids are able to biomagnify PCBs 6-60% more than arctic salmonids. For all congeners, the lower BMF(MAX) of arctic fish contribute to their lower concentrations. For congeners with log K(ow) 7.0. These processes are controlled by the influence of lipid in the fish and their diet as well as the dependence of growth on temperature. We suggest that fish models originally calibrated for temperate systems may be directly applied to arctic lakes after accounting for the lipid content of the fish and their diet as well as water temperature. PMID:16293292

  16. Molecular characterization of "Candidatus Parilichlamydia carangidicola," a novel Chlamydia-like epitheliocystis agent in yellowtail kingfish, Seriola lalandi (Valenciennes), and the proposal of a new family, "Candidatus Parilichlamydiaceae" fam. nov. (order Chlamydiales).

    Science.gov (United States)

    Stride, M C; Polkinghorne, A; Miller, T L; Groff, J M; Lapatra, S E; Nowak, B F

    2013-03-01

    Three cohorts of farmed yellowtail kingfish (Seriola lalandi) from South Australia were examined for Chlamydia-like organisms associated with epitheliocystis. To characterize the bacteria, 38 gill samples were processed for histopathology, electron microscopy, and 16S rRNA amplification, sequencing, and phylogenetic analysis. Microscopically, the presence of membrane-enclosed cysts was observed within the gill lamellae. Also observed was hyperplasia of the epithelial cells with cytoplasmic vacuolization and fusion of the gill lamellae. Transmission electron microscopy revealed morphological features of the reticulate and intermediate bodies typical of members of the order Chlamydiales. A novel 1,393-bp 16S chlamydial rRNA sequence was amplified from gill DNA extracted from fish in all cohorts over a 3-year period that corresponded to the 16S rRNA sequence amplified directly from laser-dissected cysts. This sequence was only 87% similar to the reported "Candidatus Piscichlamydia salmonis" (AY462244) from Atlantic salmon and Arctic charr. Phylogenetic analysis of this sequence against 35 Chlamydia and Chlamydia-like bacteria revealed that this novel bacterium belongs to an undescribed family lineage in the order Chlamydiales. Based on these observations, we propose this bacterium of yellowtail kingfish be known as "Candidatus Parilichlamydia carangidicola" and that the new family be known as "Candidatus Parilichlamydiaceae." PMID:23275507

  17. Uranium accumulation in aquatic macrophytes in an uraniferous region: Relevance to natural attenuation.

    Science.gov (United States)

    Cordeiro, Cristina; Favas, Paulo J C; Pratas, João; Sarkar, Santosh Kumar; Venkatachalam, Perumal

    2016-08-01

    Phytoremediation potential of uranium (U) was investigated by submerged, free-floating and rooted emergent native aquatic macrophytes inhabiting along the streams of Horta da Vilariça, a uraniferous geochemical region of NE Portugal. The work has been undertaken with the following objectives: (i) to relate the U concentrations in water-sediment-plant system; and (ii) to identify the potentialities of aquatic plants to remediate U-contaminated waters based on accumulation pattern. A total of 25 plant species culminating 233 samples was collected from 15 study points along with surface water and contiguous sediments. Concentrations of U showed wide range of variations both in waters (0.61-5.56 μg L(-1), mean value 1.98 μg L(-1)) and sediments (124-23,910 μg kg(-1), mean value 3929 μg kg(-1)) and this is also reflected in plant species examined. The plant species exhibited the ability to accumulate U several orders of magnitude higher than the surrounding water. Maximum U concentrations was recorded in the bryophyte Scorpiurium deflexifolium (49,639 μg kg(-1)) followed by Fontinalis antipyretica (35,771 μg kg(-1)), shoots of Rorippa sylvestris (33,837 μg kg(-1)), roots of Oenanthe crocata (17,807 μg kg(-1)) as well as in Nasturtium officinale (10,995 μg kg(-1)). Scorpiurium deflexifolium displayed a high bioconcentration factor (BF) of ∼2.5 × 10(4) (mean value). The species Fontinalis antipyretica, Nasturtium officinale (roots) and Rorippa sylvestris (shoots) exhibited the mean BFs of 1.7 × 10(4), 5 × 10(3) and 4.8 × 10(3) respectively. Maximum translocation factor (TF) was very much pronounced in the rooted perennial herb Rorippa sylvestris showing extreme ability to transport U for the shoots and seems to be promising candidate to be used as bioindicator species. PMID:27164268

  18. BIO-MONITORING FOR URANIUM USING STREAM-SIDE TERRESTRIAL PLANTS AND MACROPHYTES

    Energy Technology Data Exchange (ETDEWEB)

    Caldwell, E.; Duff, M.; Hicks, T.; Coughlin, D.; Hicks, R.; Dixon, E.

    2012-01-12

    This study evaluated the abilities of various plant species to act as bio-monitors for environmental uranium (U) contamination. Vegetation and soil samples were collected from a U processing facility. The water-way fed from facility storm and processing effluents was the focal sample site as it represented a primary U transport mechanism. Soils and sediments from areas exposed to contamination possessed U concentrations that averaged 630 mg U kg{sup -1}. Aquatic mosses proved to be exceptional accumulators of U with dry weight (dw) concentrations measuring as high as 12500 mg U kg{sup -1} (approximately 1% of the dw mass was attributable to U). The macrophytes (Phragmites communis, Scripus fontinalis and Sagittaria latifolia) were also effective accumulators of U. In general, plant roots possessed higher concentrations of U than associated upper portions of plants. For terrestrial plants, the roots of Impatiens capensis had the highest observed levels of U accumulation (1030 mg kg{sup -1}), followed by the roots of Cyperus esculentus and Solidago speciosa. The concentration ratio (CR) characterized dry weight (dw) vegetative U levels relative to that in associated dw soil. The plant species that accumulated U at levels in excess of that found in the soil were: P. communis root (CR, 17.4), I. capensis root (CR, 3.1) and S. fontinalis whole plant (CR, 1.4). Seven of the highest ten CR values were found in the roots. Correlations with concentrations of other metals with U were performed, which revealed that U concentrations in the plant were strongly correlated with nickel (Ni) concentrations (correlation: 0.992; r-squared: 0.984). Uranium in plant tissue was also strongly correlated with strontium (Sr) (correlation: 0.948; r-squared: 0.899). Strontium is chemically and physically similar to calcium (Ca) and magnesium (Mg), which were also positively-correlated with U. The correlation with U and these plant nutrient minerals, including iron (Fe), suggests that active

  19. Addressing catch mechanisms in gillnets improves modeling of selectivity and estimates of mortality rates: a case study using survey data on an endangered stock of Arctic char

    DEFF Research Database (Denmark)

    Jonsson, T.; Setzer, M.; Pope, John George;

    2013-01-01

    Estimation of fish stock size distributions from survey data requires knowledge about gear selectivity. However, selectivity models rest on assumptions that seldom are analyzed. Departures from these can lead to misinterpretations and biased management recommendations. Here, we use survey data...... on great Arctic char (Salvelinus umbla) to analyze how correcting for entanglement of fish and nonisometric growth might improve estimates of selectivity curves, and subsequently estimates of size distribution and age-specific mortality. Initial selectivity curves, using the entire data set, were wide...... and asymmetric, with poor model fits. Removing potentially nonmeshed fish had the greatest positive effect on model fit, resulting in much narrower and less asymmetric selection curves, while attempting to take nonisometric growth into account, by using girth rather than length, improved model fit...

  20. Radio-transmitted electromyogram signals as indicators of swimming speed in lake trout and brown trout

    DEFF Research Database (Denmark)

    Thorstad, E.B.; Økland, F.; Koed, Anders;

    2000-01-01

    Swimming speed and average electromyogram (EMG) pulse intervals were highly correlated in individual lake trout Salvelinus namaycush (r(2)=0.52-0.89) and brown trout Salmo trutta (r(2)=0.45-0.96). High correlations were found also for pooled data in both lake trout (r(2)=0.90) and brown trout...... of the Ema stock (r(2)=0.96) and Laerdal stock (r(2)=0.96). The linear relationship between swimming speed and average EMG pulse intervals differed significantly among lake trout and the brown trout stocks. This successful calibration of EMGs to swimming speed opens the possibility of recording swimming...... speed of free swimming lake trout and brown trout in situ. EMGs can also be calibrated to oxygen consumption to record energy expenditure. (C) 2000 The Fisheries Society of the British Isles...

  1. Lake trout in the Great Lakes: Basin-wide stock collapse and binational restoration

    Science.gov (United States)

    Hansen, Michael J.; Taylor, William W.; Ferreri, C. Paola

    1999-01-01

    The lake trout (Salvelinus namaycush) was important to the human settlement of each of the Great Lakes, and underwent catastrophic collapses in each lake in the nineteenth and twentieth centuries. The timing of lake trout stock collapses were different in each lake, as were the causes of the collapses, and have been the subject of much scientific inquiry and debate. The purpose of this chapter is to summarize and review pertinent information relating historical changes in Great Lakes lake trout stocks, binational efforts to restore those stocks, and progress toward stock restoration. This presentation attempts to generalize patterns across the Great Lakes, rather than to focus within each lake. Lake specific analyses have been used to understand lake specific causes and effects, but there is continuing debate about some of these causes and effects. A basinwide review may suggest mechanisms for observed changes that are not evident by lake specific analysis.

  2. Comparative Study of Genome Divergence in Salmonids with Various Rates of Genetic Isolation

    Directory of Open Access Journals (Sweden)

    Elena A. Shubina

    2013-01-01

    Full Text Available The aim of the study is a comparative investigation of changes that certain genome parts undergo during speciation. The research was focused on divergence of coding and noncoding sequences in different groups of salmonid fishes of the Salmonidae (Salmo, Parasalmo, Oncorhynchus, and Salvelinus genera and the Coregonidae families under different levels of reproductive isolation. Two basic approaches were used: (1 PCR-RAPD with a 20–22 nt primer design with subsequent cloning and sequencing of the products and (2 a modified endonuclease restriction analysis. The restriction fragments were shown with sequencing to represent satellite DNA. Effects of speciation are found in repetitive sequences. The revelation of expressed sequences in the majority of the employed anonymous loci allows for assuming the adaptive selection during allopatric speciation in isolated char forms.

  3. Longevity of Lake Superior lake trout

    Science.gov (United States)

    Schram, Stephen T.; Fabrizio, Mary C.

    1998-01-01

    The age structure of mature lake trout Salvelinus namaycush from the Wisconsin waters of Lake Superior increased following a population recovery that has taken place since the 1960s. As the population aged, it became apparent that scales were unreliable aging structures. Beginning in 1986, we examined both scale and sagittal otolith ages from tagged fish with a known period at liberty. We found large discrepancies in scale and sagittal otolith ages of mature fish, such that scale ages were biased low. We estimated lake trout living up to 42 years, which is greater than previously reported from Lake Superior. Investigators studying lake trout population dynamics in the Great Lakes should be aware that lake trout can live longer than previously thought.

  4. A blood chemistry profile for lake trout

    Science.gov (United States)

    Edsall, Carol Cotant

    1999-01-01

    A blood chemistry profile for lake trout Salvelinus namaycush was developed by establishing baseline ranges for several clinical chemistry tests (glucose, total protein, amylase, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, creatine kinase, calcium, and magnesium). Measurements were made accurately and rapidly with a Kodak Ektachem DT60 Analyzer and the Ektachem DTSC Module. Blood serum was collected from both laboratory-reared lake trout (1978 and 1986 year-classes) and feral spawning trout from Lake Michigan and then analyzed in the laboratory. No clinically significant differences were found between samples analyzed fresh and those frozen for 1 or 6 weeks. The ranges in chemistry variables for feral lake trout were generally wider than those for laboratory-reared lake trout, and significant differences existed between male and female feral lake trout for several tests. Blood chemistry profiles also varied seasonally on fish sampled repeatedly.

  5. Assessing the feasibility of native fish reintroductions: a framework and example applied to bull trout in the Clackamas River, Oregon

    Science.gov (United States)

    Dunham, Jason B.; Gallo, Kirsten

    2008-01-01

    In a species conservation context, translocations can be an important tool, but they frequently fail to successfully establish new populations. We consider the case of reintroductions for bull trout (Salvelinus confluentus), a federally-listed threatened species with a widespread but declining distribution in western North America. Our specific objectives in this work were to: 1) develop a general framework for assessing the feasibility of reintroduction for bull trout, 2) provide a detailed example of implementing this framework to assess the feasibility of reintroducing bull trout in the Clackamas River, Oregon, and 3) discuss the implications of this effort in the more general context of fish reintroductions as a conservation tool. Review of several case histories and our assessment of the Clackamas River suggest that an attempt to reintroduce bull trout could be successful, assuming adequate resources are committed to the subsequent stages of implementation, monitoring, and evaluation.

  6. Toxicity of fluoride to aquatic species and evaluation of toxicity modifying factors.

    Science.gov (United States)

    Pearcy, Krysta; Elphick, James; Burnett-Seidel, Charlene

    2015-07-01

    The present study was performed to investigate the toxicity of fluoride to a variety of freshwater aquatic organisms and to establish whether water quality variables contribute substantively to modifying its toxicity. Water hardness, chloride, and alkalinity were tested as possible toxicity modifying factors for fluoride using acute toxicity tests with Hyalella azteca and Oncorhynchus mykiss. Chloride appeared to be the major toxicity modifying factor for fluoride in these acute toxicity tests. The chronic toxicity of fluoride was evaluated with a variety of species, including 3 fish (Pimephales promelas, O. mykiss, and Salvelinus namaycush), 3 invertebrates (Ceriodaphnia dubia, H. azteca, and Chironomus dilutus), 1 plant (Lemna minor), and 1 alga (Pseudokirchneriella subcapitata). Hyalella azteca was the most sensitive species overall, and O. mykiss was the most sensitive species of fish. The role of chloride as a toxicity modifying factor was inconsistent between species in the chronic toxicity tests.

  7. Toxicity of fluoride to aquatic species and evaluation of toxicity modifying factors.

    Science.gov (United States)

    Pearcy, Krysta; Elphick, James; Burnett-Seidel, Charlene

    2015-07-01

    The present study was performed to investigate the toxicity of fluoride to a variety of freshwater aquatic organisms and to establish whether water quality variables contribute substantively to modifying its toxicity. Water hardness, chloride, and alkalinity were tested as possible toxicity modifying factors for fluoride using acute toxicity tests with Hyalella azteca and Oncorhynchus mykiss. Chloride appeared to be the major toxicity modifying factor for fluoride in these acute toxicity tests. The chronic toxicity of fluoride was evaluated with a variety of species, including 3 fish (Pimephales promelas, O. mykiss, and Salvelinus namaycush), 3 invertebrates (Ceriodaphnia dubia, H. azteca, and Chironomus dilutus), 1 plant (Lemna minor), and 1 alga (Pseudokirchneriella subcapitata). Hyalella azteca was the most sensitive species overall, and O. mykiss was the most sensitive species of fish. The role of chloride as a toxicity modifying factor was inconsistent between species in the chronic toxicity tests. PMID:25732700

  8. Fisheries Habitat Evaluation on Tributaries of the Coeur d`Alene Indian Reservation : 1990 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Graves, Suzy

    1992-02-01

    Ranking criteria were developed to rate 19 tributaries on the Coeur d`Alene Indiana Reservation for potential of habitat enhancement for westslope cutthroat trout, Oncorhynchus clarki lewisi, and bull trout, Salvelinus malma. Cutthroat and bull trout habitat requirements, derived from an extensive literature review of each species, were compared to the physical and biological parameters of each stream observed during an aerial -- helicopter survey. Ten tributaries were selected for further study, using the ranking criteria that were derived. The most favorable ratings were awarded to streams that were located completely on the reservation, displayed highest potential for improvement and enhancement, had no barriers to fish migration, good road access, and a gradient acceptable to cutthroat and bull trout habitation. The ten streams selected for study were Bellgrove, Fighting, Lake, Squaw, Plummer, Little Plummer, Benewah, Alder, Hell`s Gulch and Evans creeks.

  9. Fish resource data from the Snare River, Northwest Territories

    International Nuclear Information System (INIS)

    An extensive fish sampling and tagging program was conducted on the Snare River, Northwest Territories, in order to collect baseline data on the fish populations in sections of the river altered by hydroelectric projects. Fish populations were sampled from May to July 1977 in five sections of the river that were influenced by development of hydropower at three dams currently on line; 530 tagged fish were also released. The biweekly catch composition in experimental gill nets for each study area and the catch per gill net mesh size are presented for walleye (Stizostedion vitreum), lake trout (Salvelinus namaycush), lake whitefish (Coregonus clupeaformis), lake cisco (Coregonus artedi), northern pike (Esox lucius), white sucker (Catostomus commersoni), and longnose sucker (Catostomus catostomus). Age-specific data on length, weight, age, sex, and maturity are also included. 7 refs., 12 figs., 42 tabs

  10. Status of Oregon's Bull Trout.

    Energy Technology Data Exchange (ETDEWEB)

    Buchanan, David V.; Hanson, Mary L.; Hooton, Robert M.

    1997-10-01

    Limited historical references indicate that bull trout Salvelinus confluentus in Oregon were once widely spread throughout at least 12 basins in the Klamath River and Columbia River systems. No bull trout have been observed in Oregon's coastal systems. A total of 69 bull trout populations in 12 basins are currently identified in Oregon. A comparison of the 1991 bull trout status (Ratliff and Howell 1992) to the revised 1996 status found that 7 populations were newly discovered and 1 population showed a positive or upgraded status while 22 populations showed a negative or downgraded status. The general downgrading of 32% of Oregon's bull trout populations appears largely due to increased survey efforts and increased survey accuracy rather than reduced numbers or distribution. However, three populations in the upper Klamath Basin, two in the Walla Walla Basin, and one in the Willamette Basin showed decreases in estimated population abundance or distribution.

  11. Optimization of conditions for the extraction of phorbol esters from Jatropha oil

    Energy Technology Data Exchange (ETDEWEB)

    Devappa, Rakshit K.; Makkar, H.P.S.; Becker, K. [Institute for Animal Production in the Tropics and Subtropics (480b), University of Hohenheim, 70593 Stuttgart (Germany)

    2010-08-15

    The production of Jatropha curcas seeds as a biodiesel feedstock is expected to reach 160 Mt by 2017. The present study aims at extracting phorbol esters (PEs) as a co-product from Jatropha oil before processing it to biodiesel. The conditions were optimized for extraction of PEs in organic solvents by using a magnetic stirrer and an Ultra turrax. The extent of reduction in PEs was >99.4% in methanol using any of the stirring tools. However, the extraction using Ultra turrax affected considerably the colour of the remaining oil. Therefore, further solvent:oil ratio, time and temperature were optimized using a magnetic stirrer to get PE rich fraction-I (48.4 mg PEs g{sup -1}) and virtually PE-free oil. PEs were 14 fold higher in this fraction than the control oil. PEs, extracted in methanol from the untreated Jatropha oil, at 1 mg L{sup -1} produced 100% mortality in snails (Physa fontinalis). The methanol extract from virtually PE-free oil when concentrated 20 and 25 time the untreated Jatropha oil (equivalent of 20 mg L{sup -1} and 25 mg L{sup -1} PEs in the control oil) was nontoxic to snails. PE rich fraction-I, obtained as a co-product, can be used in agricultural, medicinal and pharmaceutical applications and the remaining oil can be used for biodiesel preparation. The remaining oil will be friendly to the environment and workers. (author)

  12. Accumulation of arsenic by aquatic plants in large-scale field conditions: opportunities for phytoremediation and bioindication.

    Science.gov (United States)

    Favas, Paulo J C; Pratas, João; Prasad, M N V

    2012-09-01

    This work focuses on the potential of aquatic plants for bioindication and/or phytofiltration of arsenic from contaminated water. More than 71 species of aquatic plants were collected at 200 sampling points in running waters. The results for the 18 most representative plant species are presented here. The species Ranunculus trichophyllus, Ranunculus peltatus subsp. saniculifolius, Lemna minor, Azolla caroliniana and the leaves of Juncus effusus showed a very highly significant (P<0.001) positive correlation with the presence of arsenic in the water. These species may serve as arsenic indicators. The highest concentration of arsenic was found in Callitriche lusitanica (2346 mg/kg DW), Callitriche brutia (523 mg/kg DW), L. minor (430 mg/kg DW), A. caroliniana (397 mg/kg DW), R. trichophyllus (354 mg/kg DW), Callitriche stagnalis (354 mg/kg DW) and Fontinalis antipyretica (346 mg/kg DW). These results indicate the potential application of these species for phytofiltration of arsenic through constructed treatment wetlands or introduction of these plant species into natural water bodies. PMID:22820614

  13. Using devitalized moss for active biomonitoring of water pollution.

    Science.gov (United States)

    Debén, S; Fernández, J A; Carballeira, A; Aboal, J R

    2016-03-01

    This paper presents the results of an experiment carried out for the first time in situ to select a treatment to devitalize mosses for use in active biomonitoring of water pollution. Three devitalizing treatments for the aquatic moss Fontinalis antipyretica were tested (i.e. oven-drying at 100 °C, oven-drying with a 50-80-100 °C temperature ramp, and boiling in water), and the effects of these on loss of material during exposure of the transplants and on the accumulation of different heavy metals and metalloids were determined. The suitability of using devitalized samples of the terrestrial moss Sphagnum denticulatum to biomonitor aquatic environments was also tested. The structure of mosses was altered in different ways by the devitalizing treatments. Devitalization by boiling water led to significantly less loss of material (p < 0.01) than the oven-drying treatments. However, devitalization by oven-drying with a temperature ramp yielded more stable results in relation to both loss of material and accumulation of elements. With the aim of standardizing the moss bag technique, the use of F. antipyretica devitalized by oven-drying with a temperature ramp is recommended, rather than other devitalization treatments or use of S. denticulatum. PMID:26803787

  14. Influence of water hardness on accumulation and elimination of cadmium in two aquatic mosses under laboratory conditions.

    Science.gov (United States)

    Gagnon, C; Vaillancourt, G; Pazdernik, L

    1998-01-01

    This study investigated the effect of water hardness on the accumulation and elimination of cadmium (Cd) by two aquatic mosses, Fontinalis dalecarlica and Platyhypnidium riparioides, under laboratory conditions. The two mosses were exposed to nominal Cd concentrations of 0, 0.8, 2, and 10 microg . L-1, which includes the concentration range generally found in nature. The influence of three levels of water hardness (very soft: 11.7 mg . L-1; soft: 44.2 mg . L-1; and hard water: 92.3 mg . L-1 as CaCO3) was measured while maintaining the alkalinity and pH constant during the 28-day exposure. The Cd accumulation by the aquatic mosses was rapid, showing the potential of accumulation and the sensitivity of this biomonitor. Even if the actual Cd concentration in the water was low (concentration hardness comparable to that found in the Canadian shield (hardness was hard water (92.3 mg . L-1 as CaCO3). The elimination of Cd followed a very slow process for the two species studied. The elimination rates of Cd from the mosses were not influenced by water hardness.

  15. A new electrodynamic balance design for low temperature studies

    Directory of Open Access Journals (Sweden)

    H.-J. Tong

    2014-07-01

    Full Text Available In this paper we describe a newly designed cold electrodynamic balance (CEDB system, which was built to study the evaporation kinetics and freezing properties of supercooled water droplets. The temperature of the CEDB chamber at the location of the levitated water droplet can be controlled in the range: −40 to +40 °C, which is achieved using a combination of liquid nitrogen cooling and heating by positive temperature coefficient heaters. The measurement of liquid droplet radius is obtained by analyzing the Mie elastic light scattering from a 532 nm laser. The Mie scattering signal was also used to characterize and distinguish droplet freezing events; liquid droplets produce a regular fringe pattern whilst the pattern from frozen particles is irregular. The evaporation rate of singly levitated water droplets was calculated from time resolved measurements of the radii of evaporating droplets and a clear trend of the evaporation rate on temperature was measured. The statistical freezing probabilities of aqueous pollen extracts (pollen washing water are obtained in the temperature range: −4.5 to −40 °C. It was found that that pollen washing water from water birch (Betula fontinalis occidentalis pollen can act as ice nuclei in the immersion freezing mode at temperatures as warm as −22.45 (±0.65 °C.

  16. Acumulación, removilización, absorción postantesis y eficiencia de utilización de nitrógeno en trigo bajo diferentes labranzas y fertilizaciones

    Directory of Open Access Journals (Sweden)

    Golik Silvina Inés

    2003-01-01

    Full Text Available El objetivo de este trabajo fue analizar la acumulación, removilización, absorción postantesis y la eficiencia en la utilización de N bajo dos sistemas de labranza (reja y cincel y diferentes tipos de fertilización, en los cultivares de trigo pan Buck Pronto y Buck Charrúa. Los tratamientos de fertilización fueron: testigo sin el agregado de N, aplicación de 90 kg ha-1 de N como urea a la siembra, aplicación de 90 kg ha-1 de N como nitrato de amonio calcáreo a la siembra y aplicación de N como urea y como nitrato de amonio calcáreo en dosis de 45 kg ha-1 a la siembra más 45 kg ha-1 a fin de macollaje, respectivamente. Se encontraron diferencias en el N acumulado entre sistemas de labranzas; con cincel se acumuló 18 kg ha-¹ más que bajo reja, pero esto no se tradujo en el porcentaje de N contribuido al grano por removilización ni por absorción postantesis. La fertilización aumentó el N acumulado en un promedio de 50 kg ha-1. A su vez provocó un aumento en la contribución al grano del N removilizado, pero no mejoró el aporte del N absorbido postantesis, ni aún en la aplicación en dos momentos. Los cultivares presentaron diferencias en el N acumulado y en el porcentaje aportado al grano por removilización y absorción postantesis. La eficiencia de utilización del N dependió de la labranza y de la fertilización.

  17. Heat transfer in fish: are short excursions between habitats a thermoregulatory behaviour to exploit resources in an unfavourable thermal environment?

    Science.gov (United States)

    Pépino, Marc; Goyer, Katerine; Magnan, Pierre

    2015-11-01

    Temperature is the primary environmental factor affecting physiological processes in ectotherms. Heat-transfer models describe how the fish's internal temperature responds to a fluctuating thermal environment. Specifically, the rate coefficient (k), defined as the instantaneous rate of change in body temperature in relation to the difference between ambient and body temperature, summarizes the combined effects of direct thermal conduction through body mass, passive convection (intracellular and intercellular fluids) and forced convective heat transfer (cardiovascular system). The k-coefficient is widely used in fish ecology to understand how body temperature responds to changes in water temperature. The main objective of this study was to estimate the k-coefficient of brook charr equipped with internal temperature-sensitive transmitters in controlled laboratory experiments. Fish were first transferred from acclimation tanks (10°C) to tanks at 14, 19 or 23°C (warming experiments) and were then returned to the acclimation tanks (10°C; cooling experiments), thus producing six step changes in ambient temperature. We used non-linear mixed models to estimate the k-coefficient. Model comparisons indicated that the model incorporating the k-coefficient as a function of absolute temperature difference (dT: 4, 9 and 13°C) best described body temperature change. By simulating body temperature in a heterogeneous thermal environment, we provide theoretical predictions of maximum excursion duration between feeding and resting areas. Our simulations suggest that short (i.e. <60 min) excursions could be a common thermoregulatory behaviour adopted by cold freshwater fish species to sustain body temperature below a critical temperature threshold, enabling them to exploit resources in an unfavourable thermal environment.

  18. Use of Barley for the Purification of Aquaculture Wastewater in a Hydroponics System

    Directory of Open Access Journals (Sweden)

    A. M. Snow

    2008-01-01

    Full Text Available Barley was examined for its ability to remove nutrients from aquaculture wastewater. The effects of seed sterilization using ethanol and bleach and seed density on germination and plant growth were investigated. Surface sterilization of barley seeds had a negative impact on germination. Increasing the ethanol concentration and/or the bleach concentration reduced the germination percentage. Barley seeds were first germinated in water in the hydroponics system. The seedlings then received wastewater from an aquaculture system stocked with Arctic charr. During the experiment, the crops grew rapidly and fairly uniformly and showed no signs of mineral deficiency or disease. The average crop height at harvest was 25.5 cm and the yield varied from 25 to 59 t haˉ1, depending on the seed density. The hydroponically grown barley was able to significantly reduce the pollution load of the aquaculture wastewater. The TS, COD, NH4+-N, NO2--N, NO3--N, and PO43--P reductions ranged from 52.7 to 60.5%, from 72.9 to 83.1%, from 76.0 to 76.0%, from 97.6 to 99.2%, from 76.9 to 81.6% and from 87.1 to 95.1%, respectively. However, the effluent produced from the hydroponics system had slightly higher levels of TS (420-485 mg Lˉ1 than the 480 mg Lˉ1 recommended for aquatic animals. A sedimentation/filtration unit should be added to the hydroponics system.

  19. The effect of radioactive contamination of the Yenisei river on cytogenetic characteristics of aquatic plants

    Energy Technology Data Exchange (ETDEWEB)

    Bolsunovsky, A.; Medvedeva, M. [Institute of Biophysics SB Russian Academy of Sciences (Russian Federation); Muratova, E. [Institute of Forest SB Russian Academy of Sciences (Russian Federation)

    2014-07-01

    The Yenisei River, one of the world's largest rivers, is contaminated with artificial radionuclides released by one of the Russian facilities producing weapons-grade plutonium (the Mining-and-Chemical Combine, MCC), which has been in operation for many years. Aquatic plants are an important component of water ecosystems, which can accumulate high levels of radionuclides and, thus, can be used in bio-monitoring and bioremediation. The purpose of the study was to assess levels of radionuclides and to evaluate the frequency of chromosomal aberrations in samples of submerged plants collected in different parts of the Yenisei River. The following species were studied: Fontinalis antipyretica, Batrachium kauffmanii, Myriophyllum spicatum, Elodea canadensis, Ceratophyllum demersum and various Potamogeton species. Samples were collected at positions in the vicinity of the MCC discharge point, at a distance of 330 km downstream of Krasnoyarsk, and upstream of the MCC, during sampling campaigns in 2003-2012. Detailed analysis of radioactive contamination of aquatic plants of the Yenisei River revealed large-scale contamination of aquatic plants as far as 250 km downstream of the MCC. Before the last MCC reactor was shut down in 2010, about 30 radionuclides, including uranium and transuranium elements, were detected in the biomass of aquatic plants. The highest concentration factors of the major radionuclides were obtained for Fontinalis antipyretica and Potamogeton lucens. Samples of the plants collected after the shutdown of the reactor contained considerably lower activity levels of artificial radionuclides, and their diversity was significantly decreased. Results of cytogenetic investigations of aquatic plants collected when the reactor was still operating (2003-2009) suggest that at the MCC discharge site and downstream the occurrence of chromosomal aberrations in ana-telophase and metaphase cells of the plants was considerably higher (up to 30%) than in the control

  20. Accumulation of uranium by aquatic plants in field conditions: Prospects for phytoremediation

    Energy Technology Data Exchange (ETDEWEB)

    Favas, Paulo J.C., E-mail: pjcf@utad.pt [School of Life Sciences and the Environment, University of Trás-os-Montes e Alto Douro, 5001-801 Vila Real (Portugal); IMAR-CMA Marine and Environmental Research Centre, Faculty of Sciences and Technology, University of Coimbra, 3001-401 Coimbra (Portugal); Pratas, João [Department of Earth Sciences, Faculty of Sciences and Technology, University of Coimbra, 3001-401 Coimbra (Portugal); IMAR-CMA Marine and Environmental Research Centre, Faculty of Sciences and Technology, University of Coimbra, 3001-401 Coimbra (Portugal); Varun, Mayank; D' Souza, Rohan; Paul, Manoj S. [Department of Botany, St. John' s College, Agra 282 002 (India)

    2014-02-01

    A study was undertaken to determine Uranium concentrations in water and aquatic plants in the uraniferous region of Beiras, Central Portugal. Samples were collected from running water (n = 200) at places where aquatic species were observed. Plant samples were collected from 28 species of submerged, free-floating and rooted emergent plants including 2 bryophytes and 1 pteridophyte. Uranium concentrations in surface waters ranged from 0.23 to 1217 μg L{sup −1}. The aquatic plant species studied, including several previously untested species, exhibited the ability to accumulate U in concentrations many times that of the ambient water. In general submerged plants exhibited higher U content followed by rooted emergent and free floating species. The highest U concentrations were observed in the bryophyte Fontinalis antipyretica (up to 4979 mg kg{sup −1}) followed by Callitriche stagnalis (1963 mg kg{sup −1}), Callitriche hamulata (379 mg kg{sup −1}), Ranunculus peltatus subsp. saniculifolius (243 mg kg{sup −1}), Callitriche lusitanica (218 mg kg{sup −1}), and Ranunculus trichophyllus (65.8 mg kg{sup −1}). In two out of three rooted emergent species U seemed to be preferentially partitioned in rhizome/roots with highest rhizome U content recorded in Typha latifolia (380 mg kg{sup −1}). Among the free-floating species, the highest U content (42.5 mg kg{sup −1}) was seen in Lemna minor. The bryophyte F. antipyretica and Callitrichaceae members seem to be promising candidates for the development of phytofiltration methodologies based on U accumulation, abundance and biomass production. - Highlights: • Exploration of U contamination extent in uraniferous province of Central Portugal • A group of previously untested species with the ability to accumulate U was assessed • U accumulation patterns in the species indicate their potential in bioindication and phytoremediation of U-contaminated water.

  1. The impact of an industrial effluent on the water quality, submersed macrophytes and benthic macroinvertebrates in a dammed river of Central Spain.

    Science.gov (United States)

    Gonzalo, Cristina; Camargo, Julio A

    2013-10-01

    This research was conducted in the middle Duratón River (Central Spain), in the vicinity of Burgomillodo Reservoir. An industrial effluent enters the river 300 m downstream from the dam. Fluoride and turbidity levels significantly increased downstream from the effluent, these levels being to some extent affected by differential water releases from the dam. The community of submersed macrophytes exhibited slighter responses and, accordingly, lower discriminatory power than the community of benthic macroinvertebrates, this indicating that metrics and indices based on macroinvertebrates may be more suitable for the biological monitoring of water pollution and habitat degradation in dammed rivers receiving industrial effluents. However, in relation to fluoride bioaccumulation at the organism level, macrophytes (Fontinalis antipyretica and Potamogeton pectinatus) were as suitable bioindicators of fluoride pollution as macroinvertebrates (Ancylus fluviatilis and Pacifastacus leniusculus). Fluoride bioaccumulation in both hard and soft tissues of these aquatic organisms could be used as suitable bioindicator of fluoride pollution (even lower than 1 mg F(-)L(-1)) in freshwater ecosystems. Echinogammarus calvus exhibited a great sensitivity to the toxicity of fluoride ions, with a 96 h LC₅₀ of 7.5 mg F(-)L(-1) and an estimated safe concentration of 0.56 mg F(-)L(-1). The great capacity of E. calvus to take up and retain fluoride during exposures to fluoride ions would be a major cause of its great sensitivity to fluoride toxicity. It is concluded that the observed fluoride pollution might be partly responsible for the absence of this native amphipod downstream from the industrial effluent. PMID:23830885

  2. Larval morphology of benthic and interstitial water mites (Acari: Hydrachnidia) from a Luxembourgian stream.

    Science.gov (United States)

    Martin, Peter

    2016-07-22

    During a project of the Luxembourg National Museum of Natural History the parasitism of water mites dwelling a small stream (Lurenzgriecht) in the southern part of the country (Gutland) was investigated. The first step of the project was to clarify the taxonomy of the larvae of all stream-dwelling species. For that reason emergence traps were installed in the stream during 2002 and emptied every 14 days to obtain parasitized hosts. Additionally, rearing experiments were implemented in the laboratory to produce larvae of well-defined species/mothers but only with partly success. The stream has a well-known water mite inventory of 22 species, almost equally composed of true benthic species and species strongly adapted to hyporheic interstitial. The larvae of five species (Torrenticola elliptica, Atractides pumilus, Feltria motasi, Ljania macilenta, Neoacarus hibernicus) were described here as new to science. Due to the poor quality and availability of former descriptions a re-description was made for another species living in the stream (Sperchon denticulatus-gr.) and, additionally, for Hygrobates fluviatilis, a common stream-dwelling species of the area. The larvae of nine species of the Lurenzgriecht had already been sufficiently described for identification purposes (Protzia eximia, Sperchonopsis verrucosa, Sperchon clupeifer, S. thienemanni, Lebertia glabra, Atractides fonticolus, Feltria rouxi, Ljania bipapillata, Aturus fontinalis). The larvae of some other species (Aturus crinitus, Kongsbergia spp., Stygohydracarus subterraneus, Arrenurus haplurus) could neither be reared in the lab nor attributed to species for taxonomic reasons. With the exception of Kongsbergia spp. (no known larva of the genus worldwide) and Aturus crinitus (a rare species in the Lurenzgriecht) an identification key was compiled for the larvae of all known species of the stream using the new descriptions and all available information on the other ones.

  3. Plutonium concentration and (240)Pu/(239)Pu atom ratio in biota collected from Amchitka Island, Alaska: recent measurements using ICP-SFMS.

    Science.gov (United States)

    Bu, Kaixuan; Cizdziel, James V; Dasher, Douglas

    2013-10-01

    Three underground nuclear tests, including the Unites States' largest, were conducted on Amchitka Island, Alaska. Monitoring of the radiological environment around the island is challenging because of its remote location. In 2008, the Department of Energy (DOE) Office of Legacy Management (LM) became responsible for the long term maintenance and surveillance of the Amchitka site. The first DOE LM environmental survey occurred in 2011 and is part of a cycle of activities that will occur every 5 years. The University of Alaska Fairbanks, a participant in the 2011 study, provided the lichen (Cladonia spp.), freshwater moss (Fontinalis neomexicanus), kelp (Eualaria fistulosa) and horse mussel (Modiolus modiolus) samples from Amchitka Island and Adak Island (a control site). These samples were analyzed for (239)Pu and (240)Pu concentration and (240)Pu/(239)Pu atom ratio using inductively coupled plasma sector field mass spectrometry (ICP-SFMS). Plutonium concentrations and (240)Pu/(239)Pu atom ratios were generally consistent with previous terrestrial and marine studies in the region. The ((239)+)(240)Pu levels (mBq kg(-1), dry weight) ranged from 3.79 to 57.1 for lichen, 167-700 for kelp, 27.9-148 for horse mussel, and 560-573 for moss. Lichen from Adak Island had higher Pu concentrations than Amchitka Island, the difference was likely the result of the higher precipitation at Adak compared to Amchitka. The (240)Pu/(239)Pu atom ratios were significantly higher in marine samples compared to terrestrial and freshwater samples (t-test, p Pu occurred into the North Pacific Ocean, likely from the Marshall Island high yield nuclear tests, but other potential sources, such as the Kamchatka Peninsula Rybachiy Naval Base and Amchitka Island underground nuclear test site cannot be ruled out.

  4. Habitat use by fishes of Lake Superior. I. Diel patterns of habitat use in nearshore and offshore waters of the Apostle Islands region

    Science.gov (United States)

    Gorman, O.T.; Yule, D.L.; Stockwell, J.D.

    2012-01-01

    Diel patterns of distribution of fishes in nearshore (15–80 m depth) and offshore (>80 m) waters of the Apostle Islands region of Lake Superior were described using bottom trawls, mid-water trawls, and acoustic gear during day and night sampling. These data revealed three types of diel migration: diel vertical migration (DVM), diel bank migration (DBM), and no migration. DVM was expressed by fishes migrating from benthopelagic to pelagic strata and DBM was expressed by fishes migrating horizontally from deeper waters in the day to shallower waters at night while remaining within the benthopelagic stratum. Most fishes that did not exhibit diel migration showed increased nighttime densities as a result of increased activity and movement from benthic to benthopelagic strata. Rainbow Smelt (Osmerus mordax), Cisco (Coregonus artedi), Bloater (C. hoyi), Kiyi (C. kiyi), juvenile Trout-Perch (Percopsis omiscomaycus), and adult siscowet (Salvelinus namaycush siscowet) exhibited DVM. Lake Whitefish (C. clupeaformis), lean Lake Trout (Salvelinus namaycush namaycush), and juvenile siscowet exhibited DBM. Adult Trout-Perch and adult Pygmy Whitefish (Prosopium coulteri) exhibited a mixture of DBM and DVM. Burbot (Lota lota), Slimy Sculpin (Cottus cognatus), Spoonhead Sculpin (C. ricei), and Deepwater Sculpin (Myoxocephalus thompsonii) did not exhibit diel migration, but showed evidence of increased nocturnal activity. Ninespine Stickleback (Pungitius pungitius) exhibited a mixture of DVM and non-migration. Juvenile Pygmy Whitefish did not show a diel change in density or depth distribution. Species showing ontogenetic shifts in depth distribution with larger, adult life stages occupying deeper waters included, Rainbow Smelt, lean and siscowet Lake Trout, Lake Whitefish, Pygmy Whitefish, Ninespine Stickleback and Trout-Perch. Of these species, siscowet also showed an ontogenetic shift from primarily DBM as juveniles to primarily DVM as adults. Across all depths, fishes

  5. Eight hundred years of environmental changes in a high Alpine lake (Gossenköllesee, Tyrol inferred from sediment records

    Directory of Open Access Journals (Sweden)

    Roland PSENNER

    2000-09-01

    Full Text Available Documentary and sediment records (diatoms, chrysophyte stomatocysts, plant pigments, carbon and nitrogen, metals and mineral magnetics were used to reconstruct environmental changes in the high alpine lake Gossenköllesee (Tyrol, Austria during the last 800 years. The records revealed complex interactions between human impact and climate. Gossenköllesee was predominantly influenced by land-use, which supplied nutrients to the lake. Documentary records report intensive sheep and cattle farming in the area around Gossenköllesee during medieval times. Pigments and chrysophyte stomatocysts indicated high nutrient concentrations prior to ca 1770 AD. First changes in land-use, however, were already detected ca 1670 AD. In 1675 AD the “Schwaighof” near Gossenköllesee, a perennial high altitude settlement, was sold to the Earl of Spaur, and farm management probably changed. After approx. 1770 AD in-lake production was reduced, indicating a decrease in land-use. According to historical records, the perennial settlement near Gossenköllesee was abandoned by at least 1890 AD. Gossenköllesee was also affected by fish stocking. Arctic charr (Salmo trutta morpha fario L. was introduced into the lake, most probably at the end of the 15th century. A decline in carbon, nitrogen and the pigments alloxanthin (cryptophytes and astaxanthin (grazers indicate a significant removal of grazers by fish. Superimposed on human activity, climate changes have also had a significant impact on Gossenköllesee. High productivity during the 12th century suggested by the plant pigment records might have been favoured by temperature increases, indicated by pronounced glacier retreats which began during the 10th/11th century. The “Schwaighof” near Gossenköllesee was sold to the Earl of Spaur when winter temperatures declined substantially in the 1670s. Changes in C/N ratio, iron, manganese and mineral magnetics indicated increased detrital input from the catchment

  6. A Comparative Assessment of Hydroponically Grown Cereal Crops for the Purification of Aquaculture Wastewater and the Production of Fish Feed

    Directory of Open Access Journals (Sweden)

    A. M. Snow

    2008-01-01

    Full Text Available Hydroponically grown wheat, barley and oats were examined for their ability to remove nutrients from aquaculture wastewater. Wheat, barley and oats seeds were germinated in water in a hydroponics system. The seedlings then received wastewater from an aquaculture system stocked with Arctic charr. During the experiment, the crops grew rapidly and fairly uniformly and showed no signs of mineral deficiency although fungal growth was evident. The average crop heights and yields at harvest were 19.0, 25.5 and 25.2 cm and 64, 59 and 42 t ha-1 for wheat, barley and oats, respectively. The hydroponically grown wheat, barley and oats were able to significantly reduce the pollution load of the aquaculture wastewater. The TS, COD, NH4+-N, NO2--N, NO3--N and PO43--P reductions ranged from 53.3 to 57.7%, from 55.7 to 78.7%, from 76.0 to 80.0% from 85.1 to 92.9%, from 62.1 to 79.3% and from 74.1 to 93.0%, respectively. The compartments containing barley produced the highest quality effluent, which was suitable for reuse in aquaculture operations. The average TS, COD, NH4+-N, NO2--N, NO3--N and PO43--P concentrations and pH of the final effluent from the compartments containing barley were 442, 64, 0.50, 0.02, 5.89 and 0.61 mg L-1 and 6.65, respectively. The nutritive value of the three wastewater grown crops was assessed to determine the suitability of using the plants as a component in fish feed. The three terrestrial crops meet the energy, fat, Ca, Mg, P, Na, S and Mn dietary requirements of aquatic animals, exceed the carbohydrate, crude fiber, Cl, K, Cu, Fe, Se and Zn requirements of fish and shellfish and do not contain sufficient amounts of protein to meet the dietary requirements of fish and shellfish. The crops will require supplementation with a high protein source that contains low concentrations of carbohydrates, crude fiber, Cl, K, Cu, Fe, Se and Zn. Common protein sources that could be used for supplementation included fishmeal, bone meal and

  7. Empirical evaluation of predator-driven diel vertical migration in Lake Superior

    Science.gov (United States)

    Stockwell, J.D.; Hrabik, T.R.; Jensen, O.P.; Yule, D.L.; Balge, M.

    2010-01-01

    Recent studies on Lake Superior suggest that diel vertical migration (DVM) of prey (generalized Coregonus spp.) may be influenced by the density of predatory siscowet (Salvelinus namaycush). We empirically evaluated this hypothesis using data from acoustic, midwater trawl, and bottom trawl sampling at eight Lake Superior sites during three seasons in 2005 and a subset of sites in 2006. We expected the larger-bodied cisco (Coregonus artedi) to exhibit a shallower DVM compared with the smaller-bodied kiyi (Coregonus kiyi). Although DVM of kiyi and cisco were consistent with expectations of DVM as a size-dependent, predator-mediated process, we found no relationship between siscowet density and the magnitude of DVM of either coregonid. Cisco appear to have a size refuge from siscowet predation. Kiyi and siscowet co-occur in demersal habitat > 150 m during the day, where visual predation is unlikely, suggesting predator avoidance is not a factor in the daytime distribution of kiyi. Seasonal patterns of kiyi DVM were consistent with reported DVM of their primary prey Mysis relicta. Our results suggest that consideration of nonvisual foraging, rather than lightbased foraging theory (i.e., the antipredation window), is necessary to understand the processes driving DVM in deepwater systems.

  8. Ecology of the Lake Huron fish community, 1970-1999

    Science.gov (United States)

    Dobiesz, Norine E.; McLeish, David A.; Eshenroder, Randy L.; Bence, James R.; Mohr, Lloyd C.; Ebener, Mark P.; Nalepa, Thomas F.; Woldt, Aaron P.; Johnson, James E.; Argyle, Ray L.; Makarewicz, Joseph C.

    2005-01-01

    We review the status of the Lake Huron fish community between 1970 and 1999 and explore the effects of key stressors. Offshore waters changed little in terms of nutrient enrichment, while phosphorus levels declined in inner Saginaw Bay. Introduced mussels (Dreissena spp.) proliferated and may have caused a decline in Diporeia spp. This introduction could have caused a decline in lake whitefish (Coregonus clupeaformis) growth and condition, with serious repercussions for commercial fisheries. Bythotrephes, an exotic predatory cladoceran, and other new exotics may be influencing the fish community. Sea lampreys (Petromyzon marinus) remained prevalent, but intensive control efforts on the St. Mary's River may reduce their predation on salmonines. Overfishing was less of a problem than in the past, although fishing continued to reduce the amount of lake trout (Salvelinus namaycush) spawning biomass resulting from hatchery-reared fish planted to rehabilitate this species. Massive stocking programs have increased the abundance of top predators, but lake trout were rehabilitated in only one area. Successful lake trout rehabilitation may require lower densities of introduced pelagic prey fish than were seen in the 1990s, along with continued stocking of hatchery-reared lake trout and control of sea lamprey. Such reductions in prey fish could limit Pacific salmon (Oncorhynchus spp.) fisheries.

  9. Can pelagic forage fish and spawning cisco (Coregonus artedi) biomass in the western arm of Lake Superior be assessed with a single summer survey?

    Science.gov (United States)

    Yule, D.L.; Stockwell, J.D.; Schreiner, D.R.; Evrard, L.M.; Balge, M.; Hrabik, T.R.

    2009-01-01

    Management efforts to rehabilitate lake trout Salvelinus namaycush in Lake Superior have been successful and the recent increase in their numbers has led to interest in measuring biomass of pelagic prey fish species important to these predators. Lake Superior cisco Coregonus artedi currently support roe fisheries and determining the sustainability of these fisheries is an important management issue. We conducted acoustic and midwater trawl surveys of the western arm of Lake Superior during three periods: summer (July-August), October, and November 2006 to determine if a single survey can be timed to estimate biomass of both prey fish and spawning cisco. We evaluated our methods by comparing observed trawl catches of small (cisco increased substantially in November, while small bloater Coregonus hoyi biomass was lower. We compared our summer 2006 estimates of total fish biomass to the results of a summer survey in 1997 and obtained similar results. We conclude that the temporal window for obtaining biomass estimates of pelagic prey species in the western arm of Lake Superior is wide (July through October), but estimating spawning cisco abundance is best done with a November survey.

  10. Islands in the ice stream: were spawning habitats for native salmonids in the Great Lakes created by paleo-ice streams?

    Science.gov (United States)

    Riley, Stephen; Binder, Thomas R.; Tucker, Taaja R.; Menzies, John; Eyles, Nick; Janssen, John; Muir, Andrew M.; Esselman, Peter C.; Wattrus, Nigel J.; Krueger, Charles C.

    2016-01-01

    Lake trout Salvelinus namaycush, lake whitefish Coregonus clupeaformis and cisco Coregonus artedi are salmonid fishes native to the Laurentian Great Lakes that spawn on rocky substrates in the fall and early winter. After comparing the locations of spawning habitat for these species in the main basin of Lake Huron with surficial substrates and the hypothesized locations of fast-flowing Late Wisconsinan paleo-ice streams, we hypothesize that much of the spawning habitat for these species in Lake Huron is the result of deposition and erosion by paleo-ice streams. This hypothesis may represent a new framework for the identification and protection of spawning habitat for these native species, some of which are currently rare or extirpated in some of the Great Lakes. We further suggest that paleo-ice streams may have been responsible for the creation of native salmonid spawning habitat elsewhere in the Great Lakes and in other glaciated landscapes.

  11. Diplostomum von Nordmann, 1832 (Digenea: Diplostomidae) in the sub-Arctic: descriptions of the larval stages of six species discovered recently in Iceland.

    Science.gov (United States)

    Faltýnková, Anna; Georgieva, Simona; Kostadinova, Aneta; Blasco-Costa, Isabel; Scholz, Tomáš; Skírnisson, Karl

    2014-11-01

    Frequent infections with Diplostomum spp. (Digenea: Diplostomidae) were found in the freshwater snail Radix peregra (Müller) and three fish species, the salmonids Salmo trutta fario L., Salvelinus alpinus (L.) and the gasterosteid Gasterosteus aculeatus L., collected in four lakes in south-western Iceland in 2012. Detailed analysis of the isolates integrating molecular, morphological and ecological data revealed that these belong to Diplostomum spathaceum (Rudolphi, 1819) and five putative new species (three infecting both snails and fish). This paper provides detailed descriptions of the metacercariae of the six species-level lineages of Diplostomum spp. and of the cercariae of three of the lineages discovered in Iceland with comments on the application of ITS1 rDNA for species distinction within Diplostomum von Nordmann, 1832 in the light of the novel data. We strongly suggest the use of molecular evidence based on cox1 gene sequences (in addition to ITS1-5.8S-ITS2 sequences) in association with detailed assessment of the morphology of the larval stages in future studies of Diplostomum spp. in fish and snails.

  12. Influences of body size and environmental factors on autumn downstream migration of bull trout in the Boise River, Idaho

    Science.gov (United States)

    Monnot, L.; Dunham, J.B.; Hoem, T.; Koetsier, P.

    2008-01-01

    Many fishes migrate extensively through stream networks, yet patterns are commonly described only in terms of the origin and destination of migration (e.g., between natal and feeding habitats). To better understand patterns of migration in bull trout,Salvelinus confluentus we studied the influences of body size (total length [TL]) and environmental factors (stream temperature and discharge) on migrations in the Boise River basin, Idaho. During the autumns of 2001-2003, we tracked the downstream migrations of 174 radio-tagged bull trout ranging in size from 21 to 73 cm TL. The results indicated that large bull trout (>30 cm) were more likely than small fish to migrate rapidly downstream after spawning in headwater streams in early autumn. Large bull trout also had a higher probability of arriving at the current terminus of migration in the system, Arrowrock Reservoir. The rate of migration by small bull trout was more variable and individuals were less likely to move into Arrowrock Reservoir. The rate of downstream migration by all fish was slower when stream discharge was greater. Temperature was not associated with the rate of migration. These findings indicate that fish size and environmentally related changes in behavior have important influences on patterns of migration. In a broader context, these results and other recent work suggest, at least in some cases, that commonly used classifications of migratory behavior may not accurately reflect the full range of behaviors and variability among individuals (or life stages) and environmental conditions. ?? Copyright by the American Fisheries Society 2008.

  13. Efficiency of Portable Antennas for Detecting Passive Integrated Transponder Tags in Stream-Dwelling Salmonids.

    Science.gov (United States)

    Banish, Nolan P; Burdick, Summer M; Moyer, Katherine R

    2016-01-01

    Portable antennas have become an increasingly common technique for tracking fish marked with passive integrated transponder (PIT) tags. We used logistic regression to evaluate how species, fish length, and physical habitat characteristics influence portable antenna detection efficiency in stream-dwelling brown trout (Salmo trutta), bull trout (Salvelinus confluentus), and redband trout (Oncorhynchus mykiss newberrii) marked with 12-mm PIT tags. We redetected 56% (20/36) of brown trout, 34% (68/202) of bull trout, and 33% (20/61) of redband trout after a recovery period of 21 to 46 hours. Models indicate support for length and species and minor support for percent boulder, large woody debris, and percent cobble as parameters important for describing variation in detection efficiency, although 95% confidence intervals for estimates were large. The odds of detecting brown trout (1.5 ± 2.2 [mean ± SE]) are approximately four times as high as bull trout (0.4 ± 1.6) or redband trout (0.3 ± 1.8) and species-specific differences may be related to length. Our reported detection efficiency for brown trout falls within the range of other studies, but is the first reported for bull trout and redband trout. Portable antennas may be a relatively unbiased way of redetecting varying sizes of all three salmonid species.

  14. Concentration and distribution of contaminants in lake trout and walleye from the Laurentian Great Lakes (2008-2012).

    Science.gov (United States)

    McGoldrick, Daryl J; Murphy, Elizabeth W

    2016-10-01

    Biomonitoring programs for persistent, bioaccumulative, and/or toxic chemicals of concern in fish tissues have been operated by the governments of Canada and the United States in the Great Lakes since the 1970's. The objectives of these programs are to assess concentrations of harmful chemicals in whole body top predator fish as an indicator of ecosystem health and to infer potential harm to fish and fish consuming wildlife in the Great Lakes Basin. Chemicals of interest are selected based upon national and binational commitments, risk assessment, and regulation, and include a wide range of compounds. This review summarizes all available data generated by Environment Canada and the United States Environmental Protection Agency for chemicals measured in whole body homogenates of Lake Trout (Salvelinus namaycush) and Walleye (Sander vitreus) for the time period spanning 2008 to 2012 from each of the five Great Lakes. The summary shows that concentrations of legacy compounds, such as, POPs listed in the Stockholm Convention and mercury continue to dominate the chemical burden of Great Lakes fish. This assessment, and others like it, can guide the creation of environmental quality targets where they are lacking, optimize chemical lists for monitoring, and prioritize chemicals of concern under agreements such as the Great Lakes Water Quality Agreement and the Stockholm Convention.

  15. Bull Trout Population Assessment in the White Salmon and Klickitat Rivers, Columbia River Gorge, Washington, 2001 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Thiesfeld, Steven L.; McPeak, Ronald H.; McNamara, Brian S. (Washington Department of Fish and Wildlife); Honanie, Isadore (Confederated Tribes and Bands, Yakama Nation)

    2002-01-01

    We utilized night snorkeling and single pass electroshocking to determine the presence or absence of bull trout Salvelinus confluentus in 26 stream reaches (3,415 m) in the White Salmon basin and in 71 stream reaches (9,005 m) in the Klickitat River basin during summer and fall 2001. We did not find any bull trout in the White Salmon River basin. In the Klickitat River basin, bull trout were found only in the West Fork Klickitat River drainage. We found bull trout in two streams not previously reported: Two Lakes Stream and an unnamed tributary to Fish Lake Stream (WRIA code number 30-0550). We attempted to capture downstream migrant bull trout in the West Fork Klickitat River by fishing a 1.5-m rotary screw trap at RM 4.3 from July 23 through October 17. Although we caught other salmonids, no bull trout were captured. The greatest limiting factor for bull trout in the West Fork Klickitat River is likely the small amount of available habitat resulting in a low total abundance, and the isolation of the population. Many of the streams are fragmented by natural falls, which are partial or complete barriers to upstream fish movement. To date, we have not been able to confirm that the occasional bull trout observed in the mainstem Klickitat River are migrating upstream into the West Fork Klickitat River.

  16. Concentration and distribution of contaminants in lake trout and walleye from the Laurentian Great Lakes (2008-2012).

    Science.gov (United States)

    McGoldrick, Daryl J; Murphy, Elizabeth W

    2016-10-01

    Biomonitoring programs for persistent, bioaccumulative, and/or toxic chemicals of concern in fish tissues have been operated by the governments of Canada and the United States in the Great Lakes since the 1970's. The objectives of these programs are to assess concentrations of harmful chemicals in whole body top predator fish as an indicator of ecosystem health and to infer potential harm to fish and fish consuming wildlife in the Great Lakes Basin. Chemicals of interest are selected based upon national and binational commitments, risk assessment, and regulation, and include a wide range of compounds. This review summarizes all available data generated by Environment Canada and the United States Environmental Protection Agency for chemicals measured in whole body homogenates of Lake Trout (Salvelinus namaycush) and Walleye (Sander vitreus) for the time period spanning 2008 to 2012 from each of the five Great Lakes. The summary shows that concentrations of legacy compounds, such as, POPs listed in the Stockholm Convention and mercury continue to dominate the chemical burden of Great Lakes fish. This assessment, and others like it, can guide the creation of environmental quality targets where they are lacking, optimize chemical lists for monitoring, and prioritize chemicals of concern under agreements such as the Great Lakes Water Quality Agreement and the Stockholm Convention. PMID:26740246

  17. A New Fluorinated Surfactant Contaminant in Biota: Perfluorobutane Sulfonamide in Several Fish Species.

    Science.gov (United States)

    Chu, Shaogang; Letcher, Robert J; McGoldrick, Daryl J; Backus, Sean M

    2016-01-19

    Environmental contamination and regulation of longer-chain perfluoroalkyl substances (PFASs) such as perfluorooctanesulfonate (PFOS) has given rise to the increased use of shorter-chain PFASs as alternatives in new products, although confirmation of their presence in the environment remains limited. In this study, the PFAS alternative, perfluoro-1-butane-sulfonamide (FBSA), was identified for the first time in biota in homogenate samples of fish by liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-Q-ToF-MS) and quantified by ultra high performance liquid chromatography-triple quadrupole mass spectrometry (UHPLC-QQQ-MS/MS). In one flounder (Platichthys flesus) muscle sample from the Western Scheldt, The Netherlands, FBSA concentration was at 80.12 ng/g wet weight (w.w.) and was exceeded only by PFOS. FBSA was also detected in 32 out of 33 samples of freshwater fish collected (2009-2010) from water bodies across Canada. In lake trout (Salvelinus namaycush) from northern Canada (e.g., Lake Kusawa (Yukon Territory), Great Bear Lake (Northwest Territories and in the Arctic), and Lake Athabasca (northern Alberta)), the concentrations of FBSA ranged from below method detection limit (supermarket in Ottawa (ON, Canada), FBSA concentrations were the lowest of all fish and ranged from chain perfluoroalkyl-based products.

  18. Toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) during lake trout early life stage development

    International Nuclear Information System (INIS)

    The presence of halogenated aromatic hydrocarbons has been proposed to explain early life stage mortality seen in lake trout (Salvelinus namaycush) from the Great Lakes. Three years of experiments show that lake trout sac fry are extremely sensitive to TCDD. Newly fertilized lake trout eggs exposed to vehicle or graded water concentrations of 3H-TCDD for 48 hr accumulated 0, 40, 55, 60, 70, 110, 150, 170, 280, 370 or 530 ppt (pg 3H-TCDD/g egg). The 3H-TCDD persisted in the egg and sac fry stages (t1/2 = 349 days), but was rapidly eliminated in the fry stage (t1/2=40 days). Egg stage mortality was unaffected by TCDD (11%, mean); however, at the onset of hatching there was a dose-related increase in larvae dying half-hatched. The greatest dose-related mortality occurred in the sac fry stage and was associated with subcutaneous edema of the yolk sac membrane and hemorrhages, morphologically resembling blue-sac disease. Cumulative mortality at swim up was 19% (vehicle), 20-28% (40-60), 45% (70), 74% (110), and 100% (≥150 ppt 3H-TCDD). The LD50 in sac fry based on the 3H-TCDD egg burden was 75 ppt (71-77 ppt, 95% C.I.)

  19. Bathymetry, morphology, and lakebed geologic characteristics of potential Kokanee salmon spawning habitat in Lake Pend Oreille, Bayview and Lakeview quadrangles, Idaho

    Science.gov (United States)

    Barton, Gary J.; Dux, Andrew M.

    2013-01-01

    Kokanee salmon (Oncorhynchus nerka) are a keystone species in Lake Pend Oreille in northern Idaho, historically supporting a high-yield recreational fishery and serving as the primary prey for the threatened native bull trout (Salvelinus confluentus) and the Gerrard-strain rainbow trout (Oncorhynchus mykiss). After 1965, the kokanee population rapidly declined and has remained at a low level of abundance. Lake Pend Oreille is one of the deepest lakes in the United States, the largest lake in Idaho, and home to the U.S. Navy Acoustic Research Detachment Base. The U.S. Geological Survey and Idaho Department of Fish and Game are mapping the bathymetry, morphology, and the lakebed geologic units and embeddedness of potential kokanee salmon spawning habitat in Lake Pend Oreille. Relations between lake morphology, lakebed geologic units, and substrate embeddedness are characterized for the shore zone, rise zone, and open water in bays and the main stem of the lake. This detailed knowledge of physical habitat along the shoreline of Lake Pend Oreille is necessary to better evaluate and develop kokanee recovery actions.

  20. Absence of fractionation of mercury isotopes during trophic transfer of methylmercury to freshwater fish in captivity

    Science.gov (United States)

    Kwon, Sae Yun; Blum, Joel D.; Carvan, Michael J.; Basu, Niladri; Head, Jessica A.; Madenjian, Charles P.; David, Solomon R.

    2012-01-01

    We performed two controlled experiments to determine the amount of mass-dependent and mass-independent fractionation (MDF and MIF) of methylmercury (MeHg) during trophic transfer into fish. In experiment 1, juvenile yellow perch (Perca flavescens) were raised in captivity on commercial food pellets and then their diet was either maintained on unamended food pellets (0.1 μg/g MeHg) or was switched to food pellets with 1.0 μg/g or 4.0 μg/g of added MeHg, for a period of 2 months. The difference in δ202Hg (MDF) and Δ199Hg (MIF) between fish tissues and food pellets with added MeHg was within the analytical uncertainty (δ202Hg, 0.07 ‰; Δ199Hg, 0.06 ‰), indicating no isotope fractionation. In experiment 2, lake trout (Salvelinus namaycush) were raised in captivity on food pellets and then shifted to a diet of bloater (Coregonus hoyi) for 6 months. The δ202Hg and Δ199Hg of the lake trout equaled the isotopic composition of the bloater after 6 months, reflecting reequilibration of the Hg isotopic composition of the fish to new food sources and a lack of isotope fractionation during trophic transfer. We suggest that the stable Hg isotope ratios in fish can be used to trace environmental sources of Hg in aquatic ecosystems.

  1. Pacific salmon (Oncorhynchus spp.) runs and consumer fitness: growth and energy storage in stream-dwelling salmonids increase with salmon spawner density

    Science.gov (United States)

    Rinella, D.J.; Wipfli, M.S.; Stricker, C.A.; Heintz, R.A.; Rinella, M.J.

    2012-01-01

    We examined how marine-derived nutrients (MDN), in the form of spawning Pacific salmon, influenced the nutritional status and δ15N of stream-dwelling fishes. We sampled juvenile coho salmon (Oncorhynchus kisutch) and Dolly Varden (Salvelinus malma) during spring and fall from 11 south-central Alaskan streams that ranged widely in spawning salmon biomass (0.1–4.7 kg·m–2). Growth rate (as indexed by RNA–DNA ratios), energy density, and δ15N enrichment in spring-sampled fishes increased with spawner biomass, indicating the persistence of spawner effects more than 6 months after salmon spawning. Point estimates suggest that spawner effects on nutrition were substantially greater for coho salmon than Dolly Varden (268% and 175% greater for growth and energy, respectively), indicating that both species benefitted physiologically, but that juvenile coho salmon accrued more benefits than Dolly Varden. Although the data were less conclusive for fall- than spring-sampled fish, they do suggest spawner effects were also generally positive during fall, soon after salmon spawned. In a follow-up analysis where growth rate and energy density were modeled as a function of δ15N enrichment, results suggested that both increased with MDN assimilation, especially in juvenile coho salmon. Our results support the importance of salmon runs to the nutritional ecology of stream-dwelling fishes.

  2. Marine Habitat Use by Anadromous Bull Trout from the Skagit River, Washington

    Science.gov (United States)

    Hayes, Michael C.; Rubin, Steve P.; Reisenbichler, Reginald; Goetz, Fred A.; Jeanes, Eric; McBride, Aundrea

    2011-01-01

    Acoustic telemetry was used to describe fish positions and marine habitat use by tagged bull trout Salvelinus confluentus from the Skagit River, Washington. In March and April 2006, 20 fish were captured and tagged in the lower Skagit River, while 15 fish from the Swinomish Channel were tagged during May and June. Sixteen fish tagged in 2004 and 2005 were also detected during the study. Fish entered Skagit Bay from March to May and returned to the river from May to August. The saltwater residency for the 13 fish detected during the out-migration and return migration ranged from 36 to 133 d (mean ± SD, 75 ± 22 d). Most bull trout were detected less than 14 km (8.5 ± 4.4 km) from the Skagit River, and several bay residents used the Swinomish Channel while migrating. The bull trout detected in the bay were associated with the shoreline (distance from shore, 0.32 ± 0.27 km) and occupied shallow-water habitats (mean water column depth, Zostera sp.) vegetation classes made up more than 70% of the area used by bull trout. Our results will help managers identify specific nearshore areas that may require further protection to sustain the unique anadromous life history of bull trout.

  3. Use of rehabilitation experiments to understand the recovery dynamics of acid-stressed fish populations.

    Science.gov (United States)

    Snucins, Ed; Gunn, John M

    2003-04-01

    We used rehabilitation experiments involving the stocking of 2 native sportfish, lake trout (Salvelinus namaycush) and smallmouth bass (Micropterus dolomieu), in combination with recent fish community surveys, to study the recovery dynamics of fish populations in acid-stressed lakes near Sudbury and Killarney, Ontario, Canada. Population recovery rates differed between the 2 species. Introduced lake trout did poorly in species-rich lakes and exhibited slower growth, lower survival and delayed recruitment. Smallmouth bass, in contrast, readily colonized species-rich lakes. The biomass of natural smallmouth bass recruits increased to reference lake levels within 5 years following water quality recovery and spawning by stocked fish, whereas the biomass of natural lake trout recruits remained well below reference levels 5-15 years after water quality recovery and spawning by adults occurred. We document introductions by anglers of smallmouth bass into acid-damaged lake trout lakes, including some lakes that did not contain bass prior to acidification. This range expansion of a warm-water species (bass) that can alter food-web structure and reduce the growth of a cold-water species (trout), illustrates the potential for the combination of climate warming and species introductions to greatly alter the biological recovery endpoints in acid-stressed lakes. PMID:12839203

  4. Use of Rehabilitation Experiments to Understand the Recovery Dynamics of Acid-stressed Fish Populations

    Energy Technology Data Exchange (ETDEWEB)

    Snucins, Ed; Gunn, John M. [Laurentian Univ., Sudbury, ON (Canada). Dept. of Biology

    2003-04-01

    We used rehabilitation experiments involving the stocking of 2 native sportfish, lake trout (Salvelinus namaycush) and smallmouth bass (Micropterus dolomieu), in combination with recent fish community surveys, to study the recovery dynamics of fish populations in acid-stressed lakes near Sudbury and Killarney, Ontario, Canada. Population recovery rates differed between the 2 species. Introduced lake trout did poorly in species-rich lakes and exhibited slower growth, lower survival and delayed recruitment. Smallmouth bass, in contrast, readily colonized species-rich lakes. The biomass of natural smallmouth bass recruits increased to reference lake levels within 5 years following water quality recovery and spawning by stocked fish, whereas the biomass of natural lake trout recruits remained well below reference levels 5-15 years after water quality recovery and spawning by adults occurred. We document introductions by anglers of smallmouth bass into acid-damaged lake rout lakes, including some lakes that did not contain bass prior to acidification. This range expansion of a warm-water species (bass) that can alter food-web structure and reduce the growth of a cold water species (trout), illustrates the potential for the combination of climate warming and species introductions to greatly alter the biological recovery endpoints in acid-stressed lakes.

  5. Efficiency of Portable Antennas for Detecting Passive Integrated Transponder Tags in Stream-Dwelling Salmonids.

    Science.gov (United States)

    Banish, Nolan P; Burdick, Summer M; Moyer, Katherine R

    2016-01-01

    Portable antennas have become an increasingly common technique for tracking fish marked with passive integrated transponder (PIT) tags. We used logistic regression to evaluate how species, fish length, and physical habitat characteristics influence portable antenna detection efficiency in stream-dwelling brown trout (Salmo trutta), bull trout (Salvelinus confluentus), and redband trout (Oncorhynchus mykiss newberrii) marked with 12-mm PIT tags. We redetected 56% (20/36) of brown trout, 34% (68/202) of bull trout, and 33% (20/61) of redband trout after a recovery period of 21 to 46 hours. Models indicate support for length and species and minor support for percent boulder, large woody debris, and percent cobble as parameters important for describing variation in detection efficiency, although 95% confidence intervals for estimates were large. The odds of detecting brown trout (1.5 ± 2.2 [mean ± SE]) are approximately four times as high as bull trout (0.4 ± 1.6) or redband trout (0.3 ± 1.8) and species-specific differences may be related to length. Our reported detection efficiency for brown trout falls within the range of other studies, but is the first reported for bull trout and redband trout. Portable antennas may be a relatively unbiased way of redetecting varying sizes of all three salmonid species. PMID:26901317

  6. Morphological variation of siscowet lake trout in Lake Superior

    Science.gov (United States)

    Bronte, C.R.; Moore, S.A.

    2007-01-01

    Historically, Lake Superior has contained many morphologically distinct forms of the lake trout Salvelinus namaycush that have occupied specific depths and locations and spawned at specific times of the year. Today, as was probably the case historically, the siscowet morphotype is the most abundant. Recent interest in harvesting siscowets to extract oil containing omega-3 fatty acids will require additional knowledge of the biology and stock structure of these lightly exploited populations. The objective of this study was to determine whether shape differences exist among siscowet populations across Lake Superior and whether these shape differences can be used to infer stock structure. Morphometric analysis (truss protocol) was used to differentiate among siscowets sampled from 23 locations in Lake Superior. We analyzed 31 distance measurements among 14 anatomical landmarks taken from digital images of fish recorded in the field. Cluster analysis of size-corrected data separated fish into three geographic groups: The Isle Royale, eastern (Michigan), and western regions (Michigan). Finer scales of stock structure were also suggested. Discriminant function analysis demonstrated that head measurements contributed to most of the observed variation. Cross-validation classification rates indicated that 67–71% of individual fish were correctly classified to their region of capture. This is the first study to present shape differences associated with location within a lake trout morphotype in Lake Superior.

  7. Diet and prey selection by Lake Superior lake trout during springs 1986-2001

    Science.gov (United States)

    Ray, B.A.; Hrabik, T.R.; Ebener, M.P.; Gorman, O.T.; Schreiner, D.R.; Schram, S.T.; Sitar, S.P.; Mattes, W.P.; Bronte, C.R.

    2007-01-01

    We describe the diet and prey selectivity of lean (Salvelinus namaycush namaycush) and siscowet lake trout (S. n. siscowet) collected during spring (April–June) from Lake Superior during 1986–2001. We estimated prey selectivity by comparing prey numerical abundance estimates from spring bottom trawl surveys and lake trout diet information in similar areas from spring gill net surveys conducted annually in Lake Superior. Rainbow smelt (Osmerus mordax) was the most common prey and was positively selected by both lean and siscowet lake trout throughout the study. Selection by lean lake trout for coregonine (Coregonus spp.) prey increased after 1991 and corresponded with a slight decrease in selection for rainbow smelt. Siscowet positively selected for rainbow smelt after 1998, a change that was coincident with the decrease in selection for this prey item by lean lake trout. However, diet overlap between lean and siscowet lake trout was not strong and did not change significantly over the study period. Rainbow smelt remains an important prey species for lake trout in Lake Superior despite declines in abundance.

  8. Lake trout in northern Lake Huron spawn on submerged drumlins

    Science.gov (United States)

    Riley, Stephen C.; Binder, Thomas; Wattrus, Nigel J.; Faust, Matthew D.; Janssen, John; Menzies, John; Marsden, J. Ellen; Ebener, Mark P.; Bronte, Charles R.; He, Ji X.; Tucker, Taaja R.; Hansen, Michael J.; Thompson, Henry T.; Muir, Andrew M.; Krueger, Charles C.

    2014-01-01

    Recent observations of spawning lake trout Salvelinus namaycush near Drummond Island in northern Lake Huron indicate that lake trout use drumlins, landforms created in subglacial environments by the action of ice sheets, as a primary spawning habitat. From these observations, we generated a hypothesis that may in part explain locations chosen by lake trout for spawning. Most salmonines spawn in streams where they rely on streamflows to sort and clean sediments to create good spawning habitat. Flows sufficient to sort larger sediment sizes are generally lacking in lakes, but some glacial bedforms contain large pockets of sorted sediments that can provide the interstitial spaces necessary for lake trout egg incubation, particularly if these bedforms are situated such that lake currents can penetrate these sediments. We hypothesize that sediment inclusions from glacial scavenging and sediment sorting that occurred during the creation of bedforms such as drumlins, end moraines, and eskers create suitable conditions for lake trout egg incubation, particularly where these bedforms interact with lake currents to remove fine sediments. Further, these bedforms may provide high-quality lake trout spawning habitat at many locations in the Great Lakes and may be especially important along the southern edge of the range of the species. A better understanding of the role of glacially-derived bedforms in the creation of lake trout spawning habitat may help develop powerful predictors of lake trout spawning locations, provide insight into the evolution of unique spawning behaviors by lake trout, and aid in lake trout restoration in the Great Lakes.

  9. Effects of activity and energy budget balancing algorithm on laboratory performance of a fish bioenergetics model

    Science.gov (United States)

    Madenjian, Charles P.; David, Solomon R.; Pothoven, Steven A.

    2012-01-01

    We evaluated the performance of the Wisconsin bioenergetics model for lake trout Salvelinus namaycush that were fed ad libitum in laboratory tanks under regimes of low activity and high activity. In addition, we compared model performance under two different model algorithms: (1) balancing the lake trout energy budget on day t based on lake trout energy density on day t and (2) balancing the lake trout energy budget on day t based on lake trout energy density on day t + 1. Results indicated that the model significantly underestimated consumption for both inactive and active lake trout when algorithm 1 was used and that the degree of underestimation was similar for the two activity levels. In contrast, model performance substantially improved when using algorithm 2, as no detectable bias was found in model predictions of consumption for inactive fish and only a slight degree of overestimation was detected for active fish. The energy budget was accurately balanced by using algorithm 2 but not by using algorithm 1. Based on the results of this study, we recommend the use of algorithm 2 to estimate food consumption by fish in the field. Our study results highlight the importance of accurately accounting for changes in fish energy density when balancing the energy budget; furthermore, these results have implications for the science of evaluating fish bioenergetics model performance and for more accurate estimation of food consumption by fish in the field when fish energy density undergoes relatively rapid changes.

  10. Heritage strain and diet of wild young of year and yearling lake trout in the main basin of Lake Huron

    Science.gov (United States)

    Roseman, E.F.; Stott, W.; O'Brien, T. P.; Riley, S.C.; Schaeffer, J.S.

    2009-01-01

    Restoration of lake trout Salvelinus namaycush stocks in Lake Huron is a fish community objective developed to promote sustainable fish communities in the lake. Between 1985 and 2004, 12.65 million lake trout were stocked into Lake Huron representing eight different genetic strains. Collections of bona fide wild fish in USGS surveys have increased in recent years and this study examined the ancestry and diet of fish collected between 2004 and 2006 to explore the ecological role they occupy in Lake Huron. Analysis of microsatellite DNA revealed that both pure strain and inter-strain hybrids were observed, and the majority of fish were classified as Seneca Lake strain or Seneca Lake hybrids. Diets of 50 wild age-0 lake trout were examined. Mysis, chironomids, and zooplankton were common prey items of wild age-0 lake trout. These results indicate that stocked fish are successfully reproducing in Lake Huron indicating a level of restoration success. However, continued changes to the benthic macroinvertebrate community, particularly declines of Mysis, may limit growth and survival of wild fish and hinder restoration efforts.

  11. Demographic characteristics of an adfluvial bull trout population in Lake Pend Oreille, Idaho

    Science.gov (United States)

    McCubbins, Jonathan L; Hansen, Michael J.; DosSantos, Joseph M; Dux, Andrew M

    2016-01-01

    Introductions of nonnative species, habitat loss, and stream fragmentation have caused the Bull Trout Salvelinus confluentus to decline throughout much of its native distribution. Consequently, in June 1998, the Bull Trout was listed under the U.S. Endangered Species Act as threatened. The Bull Trout has existed in Lake Pend Oreille and its surrounding tributaries since the last ice age, and the lake once supported a world-renowned Bull Trout fishery. To quantify the current status of the Bull Trout population in Lake Pend Oreille, Idaho, we compared the mean age, growth, maturity, and abundance with reports in a study conducted one decade earlier. Abundance was estimated by mark–recapture for Bull Trout caught in trap nets and gill nets set in Lake Pend Oreille during ongoing suppression netting of Lake Trout S. namaycushin 2007–2008. Bull Trout sampled in 2006–2008 were used to estimate age structure, survival, growth, and maturity. Estimated Bull Trout abundance was similar to that estimated one decade earlier in Lake Pend Oreille. Bull Trout residing in Lake Pend Oreille between 2006 and 2008 were between ages 4 and 14 years; their growth was fastest between ages 1 and 2 and slowed thereafter. Male and female Bull Trout matured at a similar age, but females grew faster than males, thereby maturing at a larger size. Our findings suggest that management has effectively addressed current threats to increase the likelihood of long-term persistence of the Bull Trout population in Lake Pend Oreille.

  12. Increasing thiamine concentrations in lake trout eggs from Lakes Huron and Michigan coincide with low alewife abundance

    Science.gov (United States)

    Riley, Stephen C.; Rinchard, Jacques; Honeyfield, Dale C.; Evans, Allison N.; Begnoche, Linda

    2011-01-01

    Lake trout Salvelinus namaycush in the Laurentian Great Lakes suffer from thiamine deficiency as a result of adult lake trout consuming prey containing thiaminase, a thiamine-degrading enzyme. Sufficiently low egg thiamine concentrations result in direct mortality of or sublethal effects on newly hatched lake trout fry. To determine the prevalence and severity of low thiamine in lake trout eggs, we monitored thiamine concentrations in lake trout eggs from 15 sites in Lakes Huron and Michigan from 2001 to 2009. Lake trout egg thiamine concentrations at most sites in both lakes were initially low and increased over time at 11 of 15 sites, and the proportion of females with egg thiamine concentrations lower than the recommended management objective of 4 nmol/g decreased over time at eight sites. Egg thiamine concentrations at five of six sites in Lakes Huron and Michigan were significantly inversely related to site-specific estimates of mean abundance of alewives Alosa pseudoharengus, and successful natural reproduction of lake trout has been observed in Lake Huron since the alewife population crashed. These results support the hypothesis that low egg thiamine in Great Lakes lake trout is associated with increased alewife abundance and that low alewife abundance may currently be a prerequisite for successful reproduction by lake trout in the Great Lakes.

  13. Phylogenetic and ecological characteristics associated with thiaminase activity in Laurentian Great Lakes fishes

    Science.gov (United States)

    Riley, S.C.; Evans, A.N.

    2008-01-01

    Thiamine deficiency complex (TDC) causes mortality and sublethal effects in Great Lakes salmonines and results from low concentrations of egg thiamine that are thought to be caused by thiaminolytic enzymes (i.e., thiaminase) present in the diet. This complex has the potential to undermine efforts to restore lake trout Salvelinus namaycush and severely restrict salmonid production in the Great Lakes. Although thiaminase has been found in a variety of Great Lakes fishes, the ultimate source of thiaminase in Great Lakes fishes is currently unknown. We used logistic regression analysis to investigate relationships between thiaminase activity and phylogenetic or ecological characteristics of 39 Great Lakes fish species. The taxonomically more ancestral species were more likely to show thiaminase activity than the more derived species. Species that feed at lower trophic levels and occupy benthic habitats also appeared to be more likely to show thiaminase activity; these variables were correlated with taxonomy, which was the most important predictor of thiaminase activity. Further analyses of the relationship between quantitative measures of thiaminase activity and ecological characteristics of Great Lakes fish species would provide greater insight into potential sources and pathways of thiaminase in Great Lakes food webs. ?? Copyright by the American Fisheries Society 2008.

  14. Diet of juvenile lake trout in southern Lake Ontario in relation to abundance and size of prey fishes, 1979-1987

    Science.gov (United States)

    Elrod, Joseph H.; O'Gorman, Robert

    1991-01-01

    We examined the diet of juvenile lake trout Salvelinus namaycush (zone where we caught the lake trout. Over all years combined, slimy sculpins Cottus cognatus contributed the most (39–52%) by wet weight to the diet, followed by alewives Alosa pseudoharengus(3–38%), rainbow smelt Osmerus mordax (17–43%), and johnny darters Etheostoma nigrum(2–10%). Over 90% of alewives eaten during April–May and June were age 1, and 98% of those eaten during October were age 0 (few alewives were eaten in July–August). Mean lengths of rainbow smelt and slimy sculpins in stomachs increased with size of lake trout. Juvenile lake trout generally fed opportunistically—seasonal and annual changes in diet usually reflected seasonal and annual changes in abundance of prey fishes near bottom where we captured the lake trout. Furthermore, diet within a given season varied with depth of capture of lake trout, and changes with depth in proportions of prey species in lake trout stomachs mirrored changes in proportions of the prey species in trawl catches at the same depth. Alewives (ages 0 and 1) were the only prey fish eaten in substantial quantities by both juvenile lake trout and other salmonines, and thus are a potential focus of competition between these predators.

  15. Consequences of seasonal variation in reservoir water level for predatory fishes: linking visual foraging and prey densities

    Science.gov (United States)

    Klobucar, Stephen L.; Budy, Phaedra

    2016-01-01

    In reservoirs, seasonal drawdown can alter the physical environment and may influence predatory fish performance. We investigated the performance of lake trout (Salvelinus namaycush) in a western reservoir by coupling field measurements with visual foraging and bioenergetic models at four distinct states (early summer, mid-summer, late summer, and fall). The models suggested that lake trout prey, juvenile kokanee (Oncorhynchus nerka), are limited seasonally by suitable temperature and dissolved oxygen. Accordingly, prey densities were greatest in late summer when reservoir volume was lowest and fish were concentrated by stratification. Prey encounter rates (up to 68 fish·day−1) and predator consumption are also predicted to be greatest during late summer. However, our models suggested that turbidity negatively correlates with prey detection and consumption across reservoir states. Under the most turbid conditions, lake trout did not meet physiological demands; however, during less turbid periods, predator consumption reached maximum bioenergetic efficiency. Overall, our findings demonstrate that rapid reservoir fluctuations and associated abiotic conditions can influence predator–prey interactions, and our models describe the potential impacts of water level fluctuation on valuable sport fishes.

  16. Hydrological response to timber harvest in northern Idaho: Implications for channel scour and persistence of salmonids

    Science.gov (United States)

    Tonina, D.; Luce, C.H.; Rieman, B.; Buffington, J.M.; Goodwin, P.; Clayton, S.R.; Ali, S. Md; Barry, J.J.; Berenbrock, C.

    2008-01-01

    The potential for forest harvest to increase snowmelt rates in maritime snow climates is well recognized. However, questions still exist about the magnitude of peak flow increases in basins larger than 10 km2 and the geomorphic and biological consequences of these changes. In this study, we used observations from two nearly adjacent small basins (13 and 30 km2) in the Coeur d'Alene River basin, one with recent, relatively extensive, timber harvest, and the other with little disturbance in the last 50 years to explore changes in peak flows due to timber harvest and their potential effects on fish. Peak discharge was computed for a specitic rain-on-snow event using a series of physical models that linked predicted values of snowmelt input to a runoff-routing model. Predictions indicate that timber harvest caused a 25% increase in the peak flow of the modelled event and increased the frequency of events of this magnitude from a 9-year recurrence interval to a 3-6-year event. These changes in hydrologic regime, with larger discharges at shorter recurrence intervals, are predicted to increase the depth and frequency of streambed scour, causing up to 15% added mortality of bull trout (Salvelinus confluentus) embryos. Mortality from increased scour, although not catastrophic, may have contributed to the extirpation of this species from the Coeur d'Alene basin, given the widespread timber harvest that occurred in this region. Copyright ?? 2008 John Wiley & Sons, Ltd.

  17. Assessment of Salmonids and their Habitat Conditions in the Walla Walla River Basin within Washington, 2001 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Mendel, Glen Wesley; Trump, Jeremy; Karl, David

    2002-12-01

    Concerns about the decline of native salmon and trout populations have increased among natural resource managers and the public in recent years. As a result, a multitude of initiatives have been implemented at the local, state, and federal government levels. These initiatives include management plans and actions intended to protect and restore salmonid fishes and their habitats. In 1998 bull trout (Salvelinus confluentus) were listed under the Endangered Species Act (ESA), as ''Threatened'', for the Walla Walla River and its tributaries. Steelhead (Oncorhynchus mykiss) were listed as ''Threatened'' in 1999 for the mid-Columbia River and its tributaries. These ESA listings emphasize the need for information about these threatened salmonid populations and their habitats. The Washington Department of Fish and Wildlife (WDFW) is entrusted with ''the preservation, protection, and perpetuation of fish and wildlife....[and to] maximize public recreational or commercial opportunities without impairing the supply of fish and wildlife (WAC 77.12.010).'' In consideration of this mandate, the WDFW submitted a proposal in December 1997 to the Bonneville Power Administration (BPA) for a study to assess salmonid distribution, relative abundance, genetics, and the condition of salmonid habitats in the Walla Walla River basin. The primary purposes of this project are to collect baseline biological and habitat data, to identify major data gaps, and to draw conclusions whenever possible. The study reported herein details the findings of the 2001 field season (March to November, 2001).

  18. Acoustic estimates of abundance and distribution of spawning lake trout on Sheboygan Reef in Lake Michigan

    Science.gov (United States)

    Warner, D.M.; Claramunt, R.M.; Janssen, J.; Jude, D.J.; Wattrus, N.

    2009-01-01

    Efforts to restore self-sustaining lake trout (Salvelinus namaycush) populations in the Laurentian Great Lakes have had widespread success in Lake Superior; but in other Great Lakes, populations of lake trout are maintained by stocking. Recruitment bottlenecks may be present at a number of stages of the reproduction process. To study eggs and fry, it is necessary to identify spawning locations, which is difficult in deep water. Acoustic sampling can be used to rapidly locate aggregations of fish (like spawning lake trout), describe their distribution, and estimate their abundance. To assess these capabilities for application to lake trout, we conducted an acoustic survey covering 22 km2 at Sheboygan Reef, a deep reef (trout, that lake trout were 1–2 m above bottom, and that spawning took place over specific habitat. Lake trout density exhibited a high degree of spatial structure (autocorrelation) up to a range of ~190 m, and highest lake trout and egg densities occurred over rough substrates (rubble and cobble) at the shallowest depths sampled (36–42 m). Mean lake trout density in the area surveyed (~2190 ha) was 5.8 fish/ha and the area surveyed contained an estimated 9500–16,000 large lake trout. Spatial aggregation in lake trout densities, similarity of depths and substrates at which high lake trout and egg densities occurred, and relatively low uncertainty in the lake trout density estimate indicate that acoustic sampling can be a useful complement to other sampling tools used in lake trout restoration research.

  19. Assessing the feasibility of native fish reintroductions: a framework applied to threatened bull trout

    Science.gov (United States)

    Dunham, Jason B.; Gallo, Kirsten; Shively, Dan; Allen, Chris; Goehring, Brad

    2011-01-01

    Translocations to recover native fishes have resulted in mixed success. One reason for the failure of these actions is inadequate assessments of their feasibility prior to implementation. Here, we provide a framework developed to assess the feasibility of one type of translocation-reintroduction. The framework was founded on two simple components of feasibility: the potential for recipient habitats to support a reintroduction and the potential of available donor populations to support a reintroduction. Within each component, we developed a series of key questions. The final assessment was based on a scoring system that incorporated consideration of uncertainty in available information. The result was a simple yet transparent system for assessing reintroduction feasibility that can be rapidly applied in practice. We applied this assessment framework to the potential reintroduction of threatened bull trout Salvelinus confluentus into the Clackamas River, Oregon. In this case, the assessment suggested that the degree of feasibility for reintroduction was high based on the potential of recipient habitats and available donor populations. The assessment did not provide a comprehensive treatment of all possible factors that would drive an actual decision to implement a reintroduction,

  20. Are brown trout replacing or displacing bull trout populations in a changing climate?

    Science.gov (United States)

    Al-Chokhachy, Robert K.; Schmetterling, David A.; Clancy, Chris; Saffel, Pat; Kovach, Ryan; Nyce, Leslie; Liermann, Brad; Fredenberg, Wade A.; Pierce, Ron

    2016-01-01

    Understanding how climate change may facilitate species turnover is an important step in identifying potential conservation strategies. We used data from 33 sites in western Montana to quantify climate associations with native bull trout (Salvelinus confluentus) and non-native brown trout (Salmo trutta) abundance and population growth rates (λ). We estimated λ using exponential growth state space models and delineated study sites based on bull trout use for either Spawning and Rearing (SR) or Foraging, Migrating, and Overwintering (FMO) habitat. Bull trout abundance was negatively associated with mean August stream temperatures within SR habitat (r = -0.75). Brown trout abundance was generally highest at temperatures between 12 and 14°C. We found bull trout λ were generally stable at sites with mean August temperature below 10°C but significantly decreasing, rare, or extirpated at 58% of the sites with temperatures exceeding 10°C. Brown trout λ were highest in SR and sites with temperatures exceeding 12°C. Declining bull trout λs at sites where brown trout were absent suggests brown trout are likely replacing bull trout in a warming climate.

  1. Kalispell (i.e. Kalispel) Resident Fish Project : Annual Report, 1996.

    Energy Technology Data Exchange (ETDEWEB)

    Maroney, Joseph; Donley, Christopher; Lockwood, Jr., Neil

    1997-08-01

    In 1996 the Kalispell Natural Resource Department (KNRD) in conjunction with the Washington Department of Fish and Wildlife (WDFW) continued the implementation of a habitat and population enhancement project for bull trout (Salvelinus confluentus), westslope cutthroat (Oncorhynchus clarki lewisi) and largemouth bass (Micropterus salmoides). A habitat and population assessment was conducted on Browns Creek a tributary of Cee Cee Ah Creek, one of the priority tributaries outlined in the 1995 annual report. The assessment was used to determine the type and quality of habitat that was limiting to native bull trout and cutthroat trout populations. Analysis of the habitat data indicated high amounts of sediment in the stream, low bank cover, and a lack of winter habitat. Data collected from this assessment was used to prescribe habitat enhancement measures for Browns Creek. Habitat enhancement measures, as outlined in the recommendations from the 1995 annual report, were conducted during field season 1996. Fencing and planting of riparian areas and in stream structures were implemented. As a precursor to these enhancement efforts, pre-assessments were conducted to determine the affects of the enhancement. Habitat quality, stream morphology and fish populations were pre-assessed. The construction of the largemouth bass hatchery was started in October of 1995. The KNRD, Contractors Northwest Inc. and associated subcontractors are in the process of constructing the hatchery. The projected date of hatchery completion is summer 1997.

  2. Dworshak Dam Impacts Assessment and Fisheries Investigation, 1991-1992 Progress Report.

    Energy Technology Data Exchange (ETDEWEB)

    Maiolie, Melo; Elam, Steve

    1993-11-01

    Lake Pend Oreille, 38,000 hectares, is Idaho`s largest natural lake. Fisheries for kokanee Onchorynchus nerka, rainbow trout Onchorynchus mykiss, and bull trout Salvelinus confluentus have gone through major declines over the last 40 years. To date, the decline in kokanee abundance has not been fully explained. Water level management may be the single largest contributing factor to this decline. Two aspects of water level management appear critical. Dropping water level once kokanee spawning has occurred wall correlated with poor fishery harvest five years later (r = -0.71) (alpha = 0.005). Secondly, dropping the water level more than 2 m immediately before spawning leaves wave-washed gravel high on the bank and forces kokanee to spawn in low quality substrates, which again reduces survival. Changes in water level management coincided with the sharp declines in the kokanee fishery during the 1960s. Although the water level has been stabilized once spawning has occurred, the deep drawdowns resulting in poor spawning substrates continues to cause problems for the kokanee population. Recognizing the importance of these two factors gives hope that changes in water management can reverse the 30-year trend of declining kokanee populations before they are lost from the system. The authors recommend an experimental test of higher winter lake elevation for several years to document potential changes in kokanee abundance.

  3. Assessment of the Fishery Improvement Opportunities on the Pend Oreille River, 1988 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Barber, Michael R.; Willms, Roger A.; Scholz, Allan T.

    1989-10-01

    The purpose of this study is to assess the fishery improvement opportunities on the Box Canyon portion of the Pend Oreille River. This report contains the findings of the first year of the study. Chinook salmon (Oncorhynchus tshawytscha (Walbaum)) and steelhead (Oncorhynchus mykiss (Richardson)) were present in the Pend Oreille River prior to the construction of Grand Coulee Dam. The river also contained native cutthroat trout (Oncorhynchus clarki (Richardson)), bull trout (Salvelinus confluentus (Walbaum)) and mountain whitefish (Prosopium williamsoni (Girard)). Rainbow trout were planted in the river and some grew to lengths in excess of 30 inches. With the construction of Box Canyon Dam, in 1955, the most productive section of the river was inundated. Following the construction of the dam the trout fishery declined and the populations of spiny ray fish and rough fish increased. The objectives of the first year of the study were to determine the relative abundance of each species in the river and sloughs; the population levels in fish in the river and four selected tributaries; fish growth rates; the feeding habits and abundance of preferred prey; the migration patterns; and the total fishing pressure, catch per unit effort, and total harvest by conducting a year-round creel survey. 132 refs.

  4. Dworshak Reservoir Investigations: Trout, Bass and Forage Species, 1987 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Statler, David P.

    1988-05-01

    Dworshak Dam and Reservoir is a Corps of Engineers facility located on the North Fork Clearwater River 3.2 km upstream from the Mainstem Clearwater confluence. Since initial filling in 1971, conversion of 87 km of river habitat to a 6644 hectare impoundment has had a profound influence on resident fisheries. The Nez Perce Tribe and the Idaho Department of Fish and Game (IDFG) entered into separate intergovernmental agreements with the Bonneville Power Administration in a cooperative effort to study these impacts. The kokanee Oncorhynchus nerka assessment is included in the IDFG agreement, and is not addressed in this report. This project pertains primarily to rainbow trout Salmo gairdneri, smallmouth bass (Micropterus dolomieui), and forage species. For the period November 1987 through February 1988, an estimated 4339 angler-hours were expended to catch 430 rainbow trout. An estimated 20 bull trout Salvelinus confluentus, 4 smallmouth bass, and 4 suckers Catostomus spp. were also caught. Catch rates were generally poor through the period, at .091 fish per hour for all species combined (excluding kokanee). Shasta strain hatchery rainbow trout were dominant in the creel, comprising 53.9 percent of the catch, although this strain was last planted in the reservoir in June 1986. Bank anglers caught a higher percentage (93.5 percent) of the total catch of Shasta strain rainbows than Kamloops strain rainbows (33.3 percent). 11 refs., 4 figs., 6 tabs.

  5. Modelling turnover of Cs-137 in two subarctic salmonid ecosystems

    International Nuclear Information System (INIS)

    The turnover of cesium-137 was simulated in two categories of subarctic, alpine lake ecosystems - a natural lake with Gammarus lacustris as major fish prey and a lake reservoir with introduced Mysis relicta as a new fish-food organism. The resulting concentrations of Cs-137 in two salmonid species - Arctic char (Salvelinus alpinus) and brown trout (Salmo trutta) - were calculated using a multi-compartment model. Observed data were taken from a major case study evaluating the distribution, pathways and major transport mechanisms of Chernobyl cesium through northern lake ecosystems in 1986-90. The aim of this study was to design a specific conceptual model for calculation of the levels of Cs-137 in fish from simple lake ecosystems, which could be adopted for other more complex types of lakes. A multi-compartment model of the ecosystem was designed and the equations were solved with the BIOPATH-code. The uncertainty of the results due to the uncertainty of input values was examined using the PRISM-system. The model gave good correlations to measured data for Cs-137 in water, zooplankton, macro invertebrates and fish in both lakes. The predicted levels in sediments were, however, considerably lower than the observed values. The inflow of Cs-137 from the drainage area to the two lakes was identified as the main contributor to the uncertainty of the long-term prognoses. 33 refs, 6 figs, 3 tabs

  6. Predation on lake trout eggs and fry: A modeling approach

    Science.gov (United States)

    Savino, Jacqueline F.; Hudson, Patrick L.; Fabrizio, Mary C.; Bowen, Charles A.

    1999-01-01

    A general model was developed to examine the effects of multiple predators on survival of eggs and fry of lake trout, Salvelinus namaycush, associated with spawning reefs. Three kinds of predation were simulated: epibenthic egg predators consuming eggs on the substrate surface during spawning, interstitial egg predators that can move in rocky substrate and consume incubating eggs, and fry predators. Also simulated was the effect of water temperature on predation rates. The model predicted that interstitial predation on eggs accounted for most (76 to 81%) of the predation on early life history stages of lake trout; epibenthic egg predation (12 to 19%) and fry predation (0 to 12%) had less effect on lake trout survival. Initial predation conditions chosen for the model were: epibenthic egg predation peaked at 2 eggs/mA?/d over 30 d, insterstitial egg predation at 2 eggs/mA?/d over 180 d, and fry predation at 1 fry/mA?/d over 60 d. With a starting egg density of 100 eggs/mA? and initial predation conditions, no lake trout were estimated to survive to swim-up. At egg densities of 250 eggs/mA?, 36% of the lake trout survived. At the highest egg densities examined, 500 to 1,000 eggs/mA?, estimated survival increased to about 70 to 80%. Simulated survival rates of lake trout decreased dramatically as predation rate increased but were not as sensitive to increases in the duration of predation.

  7. A new approach toward evaluation of fish bioenergetics models

    Science.gov (United States)

    Madenjian, Charles P.; O'Connor, Daniel V.; Nortrup, David A.

    2000-01-01

    A new approach was used to evaluate the Wisconsin bioenergetics model for lake trout (Salvelinus namaycush). Lake trout in laboratory tanks were fed alewife (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax), prey typical of lake trout in Lake Michigan. Food consumption and growth by lake trout during the experiment were measured. Polychlorinated biphenyl (PCB) concentrations of the alewife and rainbow smelt, as well as of the lake trout at the beginning and end of the experiment, were determined. From these data, we calculated that lake trout retained 81% of the PCBs contained within their food. In an earlier study, application of the Wisconsin lake trout bioenergetics model to growth and diet data for lake trout in Lake Michigan, in conjunction with PCB data for lake trout and prey fish from Lake Michigan, yielded an estimate of PCB assimilation efficiency from food of 81%. This close agreement in the estimates of efficiency with which lake trout retain PCBs from their food indicated that the bioenergetics model was furnishing accurate predictions of food consumption by lake trout in Lake Michigan.

  8. Reevaluation of lake trout and lake whitefish bioenergetics models

    Science.gov (United States)

    Madenjian, Charles P.; Pothoven, Steve A.; Kao, Yu-Chun

    2013-01-01

    Using a corrected algorithm for balancing the energy budget, we reevaluated the Wisconsin bioenergetics model for lake trout (Salvelinus namaycush) in the laboratory and for lake whitefish (Coregonus clupeaformis) in the laboratory and in the field. For lake trout, results showed that the bioenergetics model slightly overestimated food consumption by the lake trout when they were fed low and intermediate rations, whereas the model predicted food consumption by lake trout fed ad libitum without any detectable bias. The slight bias in model predictions for lake trout on restricted rations may have been an artifact of the feeding schedule for these fish, and we would therefore recommend application of the Wisconsin lake trout bioenergetics model to lake trout populations in the field without any revisions to the model. Use of the Wisconsin bioenergetics model for coregonids resulted in overestimation of food consumption by lake whitefish both in the laboratory and in the field by between 20 and 30%, on average. This overestimation of food consumption was most likely due to overestimation of respiration rate. We therefore adjusted the respiration component of the bioenergetics model to obtain a good fit to the observed consumption in our laboratory tanks. The adjusted model predicted the consumption in the laboratory and the field without any detectable bias. Until a detailed lake whitefish respiration study can be conducted, we recommend application of our adjusted version of the Wisconsin generalized coregonid bioenergetics model to lake whitefish populations in the field.

  9. Preliminary evaluation of a lake whitefish (Coregonus clupeaformis) bioenergetics model

    Science.gov (United States)

    Madenjian, Charles P.; Pothoven, Steven A.; Schneeberger, Philip J.; O'Connor, Daniel V.; Brandt, Stephen B.

    2005-01-01

    We conducted a preliminary evaluation of a lake whitefish (Coregonus clupeaformis) bioenergetics model by applying the model to size-at-age data for lake whitefish from northern Lake Michigan. We then compared estimates of gross growth efficiency (GGE) from our bioenergetis model with previously published estimates of GGE for bloater (C. hoyi) in Lake Michigan and for lake whitefish in Quebec. According to our model, the GGE of Lake Michigan lake whitefish decreased from 0.075 to 0.02 as age increased from 2 to 5 years. In contrast, the GGE of lake whitefish in Quebec inland waters decreased from 0.12 to 0.05 for the same ages. When our swimming-speed submodel was replaced with a submodel that had been used for lake trout (Salvelinus namaycush) in Lake Michigan and an observed predator energy density for Lake Michigan lake whitefish was employed, our model predicted that the GGE of Lake Michigan lake whitefish decreased from 0.12 to 0.04 as age increased from 2 to 5 years.

  10. Efficiency of portable antennas for detecting passive integrated transponder tags in stream-dwelling salmonids

    Science.gov (United States)

    Banish, Nolan P.; Burdick, Summer M.; Moyer, Katherine R.

    2016-01-01

    Portable antennas have become an increasingly common technique for tracking fish marked with passive integrated transponder (PIT) tags. We used logistic regression to evaluate how species, fish length, and physical habitat characteristics influence portable antenna detection efficiency in stream-dwelling brown trout (Salmo trutta), bull trout (Salvelinus confluentus), and redband trout (Oncorhynchus mykiss newberrii) marked with 12-mm PIT tags. We redetected 56% (20/36) of brown trout, 34% (68/202) of bull trout, and 33% (20/61) of redband trout after a recovery period of 21 to 46 hours. Models indicate support for length and species and minor support for percent boulder, large woody debris, and percent cobble as parameters important for describing variation in detection efficiency, although 95% confidence intervals for estimates were large. The odds of detecting brown trout (1.5 ± 2.2 [mean ± SE]) are approximately four times as high as bull trout (0.4 ± 1.6) or redband trout (0.3 ± 1.8) and species-specific differences may be related to length. Our reported detection efficiency for brown trout falls within the range of other studies, but is the first reported for bull trout and redband trout. Portable antennas may be a relatively unbiased way of redetecting varying sizes of all three salmonid species.

  11. Predicting recolonization patterns and interactions between potamodromous and anadromous salmonids in response to dam removal in the Elwha River, Washington State, USA

    Science.gov (United States)

    Brenkman, S.J.; Pess, G.R.; Torgersen, C.E.; Kloehn, K.K.; Duda, J.J.; Corbett, S.C.

    2008-01-01

    The restoration of salmonids in the Elwha River following dam removal will cause interactions between anadromous and potamodromous forms as recolonization occurs in upstream and downstream directions. Anadromous salmonids are expected to recolonize historic habitats, and rainbow trout (Oncorhynchus mykiss) and bull trout (Salvelinus confluentus) isolated above the dams for 90 years are expected to reestablish anadromy. We summarized the distribution and abundance of potamodromous salmonids, determined locations of spawning areas, and mapped natural barriers to fish migration at the watershed scale based on data collected from 1993 to 2006. Rainbow trout were far more abundant than bull trout throughout the watershed and both species were distributed up to river km 71. Spawning locations for bull trout and rainbow trout occurred in areas where we anticipate returning anadromous fish to spawn. Nonnative brook trout were confined to areas between and below the dams, and seasonal velocity barriers are expected to prevent their upstream movements. We hypothesize that the extent of interaction between potamodromous and anadromous salmonids will vary spatially due to natural barriers that will limit upstream-directed recolonization for some species of salmonids. Consequently, most competitive interactions will occur in the main stem and floodplain downstream of river km 25 and in larger tributaries. Understanding future responses of Pacific salmonids after dam removal in the Elwha River depends upon an understanding of existing conditions of the salmonid community upstream of the dams prior to dam removal.

  12. Pacific salmon (Oncorhynchus spp.) runs and consumer fitness: growth and energy storage in stream-dwelling salmonids increase with salmon spawner density

    Science.gov (United States)

    Rinella, Daniel J.; Wipfli, Mark S.; Stricker, Craig A.; Heintz, Ron A.; Rinella, Matthew J.

    2012-01-01

    We examined how marine-derived nutrients (MDN), in the form of spawning Pacific salmon, influenced the nutritional status and δ15N of stream-dwelling fishes. We sampled juvenile coho salmon (Oncorhynchus kisutch) and Dolly Varden (Salvelinus malma) during spring and fall from 11 south-central Alaskan streams that ranged widely in spawning salmon biomass (0.1–4.7 kg·m–2). Growth rate (as indexed by RNA–DNA ratios), energy density, and δ15N enrichment in spring-sampled fishes increased with spawner biomass, indicating the persistence of spawner effects more than 6 months after salmon spawning. Point estimates suggest that spawner effects on nutrition were substantially greater for coho salmon than Dolly Varden (268% and 175% greater for growth and energy, respectively), indicating that both species benefitted physiologically, but that juvenile coho salmon accrued more benefits than Dolly Varden. Although the data were less conclusive for fall- than spring-sampled fish, they do suggest spawner effects were also generally positive during fall, soon after salmon spawned. In a follow-up analysis where growth rate and energy density were modeled as a function of δ15N enrichment, results suggested that both increased with MDN assimilation, especially in juvenile coho salmon. Our results support the importance of salmon runs to the nutritional ecology of stream-dwelling fishes.

  13. Trophic connections in Lake Superior Part II: the nearshore fish community

    Science.gov (United States)

    Gamble, A.E.; Hrabik, T.R.; Yule, D.L.; Stockwell, J.D.

    2011-01-01

    We use detailed diet analyses of the predominant planktivorous, benthivorous and piscivorous fish species from Lake Superior to create a nearshore (bathymetric depths Mysis diluviana and Diporeia spp). Although the piscivorous fishes like lean lake trout (Salvelinus namaycush) fed to a lesser extent on Diporeia and Mysis, they were still strongly connected to these macroinvertebrates, which were consumed by their primary prey species (sculpin spp., rainbow smelt Osmerus mordax, and coregonines). The addition of Bythotrephes to summer/fall cisco and lake whitefish diets, and the decrease in rainbow smelt in lean lake trout diets (replaced by coregonines) were the largest observed differences relative to historic Lake Superior diet studies. Although the offshore food web of Lake Superior was simpler than nearshore in terms of number of fish species present, the two areas had remarkably similar food web structures, and both fish communities were primarily supported by Mysis and Diporeia. We conclude that declines in Mysis or Diporeia populations would have a significant impact on energy flow in Lake Superior. The food web information we generated can be used to better identify management strategies for Lake Superior.

  14. Prey selection by the Lake Superior fish community

    Science.gov (United States)

    Isaac, Edmund J.; Hrabik, Thomas R.; Stockwell, Jason D.; Gamble, Allison E.

    2012-01-01

    Mysis diluviana is an important prey item to the Lake Superior fish community as found through a recent diet study. We further evaluated this by relating the quantity of prey found in fish diets to the quantity of prey available to fish, providing insight into feeding behavior and prey preferences. We describe the seasonal prey selection of major fish species collected across 18 stations in Lake Superior in spring, summer, and fall of 2005. Of the major nearshore fish species, bloater (Coregonus hoyi), rainbow smelt (Osmerus mordax), and lake whitefish (Coregonus clupeaformis) consumed Mysis, and strongly selected Mysis over other prey items each season. However, lake whitefish also selected Bythotrephes in the fall when Bythotrephes were numerous. Cisco (Coregonus artedi), a major nearshore and offshore species, fed largely on calanoid copepods, and selected calanoid copepods (spring) and Bythotrephes (summer and fall). Cisco also targeted prey similarly across bathymetric depths. Other major offshore fish species such as kiyi (Coregonus kiyi) and deepwater sculpin (Myoxocephalus thompsoni) fed largely on Mysis, with kiyi targeting Mysis exclusively while deepwater sculpin did not prefer any single prey organism. The major offshore predator siscowet lake trout (Salvelinus namaycush siscowet) consumed deepwater sculpin and coregonines, but selected deepwater sculpin and Mysis each season, with juveniles having a higher selection for Mysis than adults. Our results suggest that Mysis is not only a commonly consumed prey item, but a highly preferred prey item for pelagic, benthic, and piscivorous fishes in nearshore and offshore waters of Lake Superior.

  15. Trophic connections in Lake Superior Part I: the offshore fish community

    Science.gov (United States)

    Gamble, A.E.; Hrabik, T.R.; Stockwell, J.D.; Yule, D.L.

    2011-01-01

    Detailed diet linkages within the offshore (> 80 m bathymetric depth) food web of Lake Superior are currently not well identified. We used analyses of fish stomach contents to create an empirically based food web model of the Lake Superior offshore fish community. Stomachs were collected seasonally (spring, summer, and fall) from nine offshore locations in 2005, using bottom and midwater trawls. In total, 2643 stomachs representing 12 fish species were examined. The predominant fish species collected were deepwater sculpin (Myoxocephalus thompsonii), siscowet (Salvelinus namaycush siscowet), kiyi (Coregonus kiyi), and cisco (Coregonus artedi). Mysis diluviana was the most common prey item, indicating that changes in Mysis abundance could have a profound impact on the entire offshore food web. Mysis was the primary diet item of deepwater sculpin (≥ 53% by mass) and kiyi (≥ 96% by mass) regardless of depth or season. The invasive Bythotrephes was an important diet component of the pelagic cisco in summer and fall. Deepwater sculpin were the primary diet item of siscowet (≥ 52% by mass), with coregonines appearing in the diet of larger (> 400 mm) siscowet. Non-metric multidimensional scaling analysis indicated that there were no statistically significant seasonal or site-specific differences in diets of deepwater sculpin, cisco, or kiyi. Site was the primary structuring factor in siscowet diets. Generally, in Lake Superior, the diet items of the dominant offshore species did not appear to be in danger from those types of major ecological shifts occurring in the lower Laurentian Great Lakes.

  16. Stunning fish with CO2 or electricity: contradictory results on behavioural and physiological stress responses.

    Science.gov (United States)

    Gräns, A; Niklasson, L; Sandblom, E; Sundell, K; Algers, B; Berg, C; Lundh, T; Axelsson, M; Sundh, H; Kiessling, A

    2016-02-01

    Studies that address fish welfare before slaughter have concluded that many of the traditional systems used to stun fish including CO2 narcosis are unacceptable as they cause avoidable stress before death. One system recommended as a better alternative is electrical stunning, however, the welfare aspects of this method are not yet fully understood. To assess welfare in aquaculture both behavioural and physiological measurements have been used, but few studies have examined the relationship between these variables. In an on-site study aversive behaviours and several physiological stress indicators, including plasma levels of cortisol and ions as well as blood physiological variables, were compared in Arctic char (Salvelinus alpinus) stunned with CO2 or electricity. Exposure to water saturated with CO2 triggered aversive struggling and escape responses for several minutes before immobilization, whereas in fish exposed to an electric current immobilization was close to instant. On average, it took 5 min for the fish to recover from electrical stunning, whereas fish stunned with CO2 did not recover. Despite this, the electrically stunned fish had more than double the plasma levels of cortisol compared with fish stunned with CO2. This result is surprising considering that the behavioural reactions were much more pronounced following CO2 exposure. These contradictory results are discussed with regard to animal welfare and stress physiological responses. The present results emphasise the importance of using an integrative and interdisciplinary approach and to include both behavioural and physiological stress indicators in order to make accurate welfare assessments of fish in aquaculture.

  17. Bull Trout Life History, Genetics, Habitat Needs, and Limiting Fact in Central and Northeast Oregon. Annual Report 1999.

    Energy Technology Data Exchange (ETDEWEB)

    Hemmingsen, Alan R.; Gunckel, Stephanie L.; Howell, Philip J.

    2001-08-01

    This section describes work accomplished in 1999 that continued to address two objectives of this project. These objectives are (1) determine the distribution of juvenile and adult bull trout Salvelinus confluentus and habitats associated with that distribution, and (2) determine fluvial and resident bull trout life history patterns. Completion of these objectives is intended through studies of bull trout in the Grande Ronde, Walla Walla, and John Day basins. These basins were selected because they provide a variety of habitats, from relatively degraded to pristine, and bull trout populations were thought to vary from relatively depressed to robust. In all three basins we used radio telemetry to determine the seasonal movements of bull trout. In the John Day and Walla Walla basins we also used traps to capture migrant bull trout. With these traps, we intended to determine the timing of bull trout movements both upstream and downstream, determine the relative abundance, size and age of migrant fish, and capture bull trout to be implanted with radio transmitters. In the John Day basin, we captured adult and juvenile bull trout from the upper John Day River and its tributaries, Call Creek, Reynolds Creek, and Roberts Creek. In the Walla Walla basin, we captured adult and juvenile bull trout from Mill Creek.

  18. Probabilistic accounting of uncertainty in forecasts of species distributions under climate change

    Science.gov (United States)

    Wenger, Seth J.; Som, Nicholas A.; Dauwalter, Daniel C.; Isaak, Daniel J.; Neville, Helen M.; Luce, Charles H.; Dunham, Jason B.; Young, Michael K.; Fausch, Kurt D.; Rieman, Bruce E.

    2013-01-01

    Forecasts of species distributions under future climates are inherently uncertain, but there have been few attempts to describe this uncertainty comprehensively in a probabilistic manner. We developed a Monte Carlo approach that accounts for uncertainty within generalized linear regression models (parameter uncertainty and residual error), uncertainty among competing models (model uncertainty), and uncertainty in future climate conditions (climate uncertainty) to produce site-specific frequency distributions of occurrence probabilities across a species’ range. We illustrated the method by forecasting suitable habitat for bull trout (Salvelinus confluentus) in the Interior Columbia River Basin, USA, under recent and projected 2040s and 2080s climate conditions. The 95% interval of total suitable habitat under recent conditions was estimated at 30.1–42.5 thousand km; this was predicted to decline to 0.5–7.9 thousand km by the 2080s. Projections for the 2080s showed that the great majority of stream segments would be unsuitable with high certainty, regardless of the climate data set or bull trout model employed. The largest contributor to uncertainty in total suitable habitat was climate uncertainty, followed by parameter uncertainty and model uncertainty. Our approach makes it possible to calculate a full distribution of possible outcomes for a species, and permits ready graphical display of uncertainty for individual locations and of total habitat.

  19. Visual sensitivity of deepwater fishes in Lake Superior.

    Directory of Open Access Journals (Sweden)

    Kelly A Harrington

    Full Text Available The predator-prey interactions in the offshore food web of Lake Superior have been well documented, but the sensory systems mediating these interactions remain unknown. The deepwater sculpin, (Myoxocephalus thompsoni, siscowet (Salvelinus namaycush siscowet, and kiyi (Coregonus kiyi inhabit low light level environments. To investigate the potential role of vision in predator-prey interactions, electroretinography was used to determine visual sensitivity for each species. Spectral sensitivity curves revealed peak sensitivity at 525 nm for each species which closely corresponds to the prevalent downwelling light spectrum at depth. To determine if sufficient light was available to mediate predator-prey interactions, visual sensitivity was correlated with the intensity of downwelling light in Lake Superior to construct visual depth profiles for each species. Sufficient daytime irradiance exists for visual interactions to approximately 325 m for siscowet and kiyi and 355 m for the deepwater sculpin during summer months. Under full moon conditions, sufficient irradiance exists to elicit ERG response to light available at approximately 30 m for the siscowet and kiyi and 45 m for the deepwater sculpin. Visual interactions are therefore possible at the depths and times when these organisms overlap in the water column indicating that vision may play a far greater role at depth in deep freshwater lakes than had been previously documented.

  20. Loss of genetic integrity in wild lake trout populations following stocking: insights from an exhaustive study of 72 lakes from Québec, Canada.

    Science.gov (United States)

    Valiquette, Eliane; Perrier, Charles; Thibault, Isabel; Bernatchez, Louis

    2014-06-01

    Stocking represents the most important management tool worldwide to increase and sustain commercial and recreational fisheries in a context of overexploitation. Genetic impacts of this practice have been investigated in many studies, which examined population and individual admixture, but few have investigated determinants of these processes. Here, we addressed these questions from the genotyping at 19 microsatellite loci of 3341 adult lake trout (Salvelinus namaycush) from 72 unstocked and stocked lakes. Results showed an increase in genetic diversity and a twofold decrease in the extent of genetic differentiation among stocked populations when compared to unstocked. Stocked populations were characterized by significant admixture at both population and individual levels. Moreover, levels of admixture in stocked populations were strongly correlated with stocking intensity and a threshold value of total homogenization between source and stocked populations was identified. Our results also suggest that under certain scenarios, the genetic impacts of stocking could be of short duration. Overall, our study emphasizes the important alteration of the genetic integrity of stocked populations and the need to better understand determinants of admixture to optimize stocking strategies and to conserve the genetic integrity of wild populations. PMID:25067947

  1. Hydroacoustic estimates of abundance and spatial distribution of pelagic prey fishes in western Lake Superior

    Science.gov (United States)

    Mason, Doran M.; Johnson, Timothy B.; Harvey, Chris J.; Kitchell, James F.; Schram, Stephen T.; Bronte, Charles R.; Hoff, MIchael H.; Lozano, Stephen J.; Trebitz, Anett S.; Schreiner, Donald R.; Lamon, E. Conrad; Hrabik, Thomas R.

    2005-01-01

    Lake herring (Coregonus artedi) and rainbow smelt (Osmerus mordax) are a valuable prey resource for the recovering lake trout (Salvelinus namaycush) in Lake Superior. However, prey biomass may be insufficient to support the current predator demand. In August 1997, we assessed the abundance and spatial distribution of pelagic coregonines and rainbow smelt in western Lake Superior by combining a 120 kHz split beam acoustics system with midwater trawls. Coregonines comprised the majority of the midwater trawl catches and the length distributions for trawl caught fish coincided with estimated sizes of acoustic targets. Overall mean pelagic prey fish biomass was 15.56 kg ha−1 with the greatest fish biomass occurring in the Apostle Islands region (27.98 kg ha−1), followed by the Duluth Minnesota region (20.22 kg ha−1), and with the lowest biomass occurring in the open waters of western Lake Superior (9.46 kg ha−1). Biomass estimates from hydroacoustics were typically 2–134 times greater than estimates derived from spring bottom trawl surveys. Prey fish biomass for Lake Superior is about order of magnitude less than acoustic estimates for Lakes Michigan and Ontario. Discrepancies observed between bioenergetics-based estimates of predator consumption of coregonines and earlier coregonine biomass estimates may be accounted for by our hydroacoustic estimates.

  2. The uranium in Kvanefjeld

    International Nuclear Information System (INIS)

    The report is a final thesis at the study of biology at the University of Copenhagen. It examines on a theoretical basis a number of possible environmental effects from a uranium mining and milling project under consideration at the Kvanefjeld site near Narssaq in South Greenland. An introductory description and discussion of the advantages and limitations of ecological baseline studies and dose committment assessments as a tool for planning and decision making is given. The leaching and atmospheric dispersion of particles, heavy metals, radionuclides and other elements from future waste rock and ore piles as well as from mill tailings at the Kvanefjeld site are analysed and discussed. Also, the mobility, transport and accumulation of potentially toxic elements in local terrestrial and aquatic ecosystems and food chains are examined. The resulting human burden are discussed with special attention given to the impact on the local population from eating lamb and seafood. A special quantitative analysis of the dispersion and biological uptake of fluoride, which is found in high concentrations in the ore, is given, focusing on the possible human intake of fluoride-polluted arctic char (Salvelinus alpinus) caught in Narrssaq River. The report at the end gives consideration to the long term problems of controlling mill tailings, discussing among other things the long term human exposure to radon and thoron daughters. (author)

  3. Lake trout otolith chronologies as multidecadal indicators of high-latitude freshwater ecosystems

    Science.gov (United States)

    Black, B.A.; Von Biela, V.R.; Zimmerman, C.E.; Brown, Randy J.

    2013-01-01

    High-latitude ecosystems are among the most vulnerable to long-term climate change, yet continuous, multidecadal indicators by which to gauge effects on biology are scarce, especially in freshwater environments. To address this issue, dendrochronology (tree-ring analysis) techniques were applied to growth-increment widths in otoliths from lake trout (Salvelinus namaycush) from the Chandler Lake system, Alaska (68.23°N, 152.70°W). All otoliths were collected in 1987 and exhibited highly synchronous patterns in growth-increment width. Increments were dated, the widths were measured, and age-related growth declines were removed using standard dendrochronology techniques. The detrended time series were averaged to generate an annually resolved chronology, which continuously spanned 1964–1984. The chronology positively and linearly correlated with August air temperature over the 22-year interval (p < 0.01), indicating that warmer summers were beneficial for growth, perhaps by increasing fish metabolic rate or lake productivity. Given the broad distribution of lake trout within North America, this study suggests that otolith chronologies could be used to examine responses between freshwater ecosystems and environmental variability across a range of temporal and spatial scales.

  4. Effects of exotic species on Yellowstone's grizzly bears

    Science.gov (United States)

    Reinhart, D.P.; Haroldson, Mark A.; Mattson, D.J.; Gunther, Kerry A.

    2001-01-01

    Humans have affected grizzly bears (Ursus arctos horribilis) by direct mortality, competition for space and resources, and introduction of exotic species. Exotic organisms that have affected grizzly bears in the Greater Yellowstone Area include common dandelion (Taraxacum officinale), nonnative clovers (Trifolium spp.), domesticated livestock, bovine brucellosis (Brucella abortus), lake trout (Salvelinus namaycush), and white pine blister rust (Cronartium ribicola). Some bears consume substantial amounts of dandelion and clover. However, these exotic foods provide little digested energy compared to higher-quality bear foods. Domestic livestock are of greater energetic value, but use of this food by bears often leads to conflicts with humans and subsequent increases in bear mortality. Lake trout, blister rust, and brucellosis diminish grizzly bears foods. Lake trout prey on native cutthroat trout (Oncorhynchus clarkii) in Yellowstone Lake; white pine blister rust has the potential to destroy native whitebark pine (Pinus albicaulis) stands; and management response to bovine brucellosis, a disease found in the Yellowstone bison (Bison bison) and elk (Cervus elaphus), could reduce populations of these 2 species. Exotic species will likely cause more harm than good for Yellowstone grizzly bears. Managers have few options to mitigate or contain the impacts of exotics on Yellowstones grizzly bears. Moreover, their potential negative impacts have only begun to unfold. Exotic species may lead to the loss of substantial highquality grizzly bear foods, including much of the bison, trout, and pine seeds that Yellowstone grizzly bears currently depend upon.

  5. Historic and modern abundance of wild lean lake trout in Michigan waters of Lake Superior: Implications for restoration goals

    Science.gov (United States)

    Wilberg, Michael J.; Hansen, Michael J.; Bronte, Charles R.

    2003-01-01

    Populations of lake trout Salvelinus namaycush in Lake Superior collapsed in the late 1950s due to overfishing and predation by sea lampreys Petromyzon marinus. A binational effort to restore the lean morphotype of lake trout began with the stocking of hatchery-reared fish followed by the chemical control of sea lampreys and closure of the commercial fishery. Previous comparisons of the contemporary abundance of wild lean lake trout with that from historic commercial fishery statistics indicate that abundance was higher historically. However, this conclusion may be biased because several factors—the inclusion of siscowet (the “fat” morphotype of lake trout) in the catch statistics, the soak time of nets, seasonal effects on catch per effort, and the confounding effects of effort targeted at lake whitefish Coregonus clupeaformis—were not accounted for. We developed new indices of historic lean lake trout abundance that correct for these biases and compared them with the assessment data from 1984 to 1998 in Michigan waters of Lake Superior. The modern (1984–1998) abundance of wild lean lake trout is at least as high as that during 1929–1943 in six of eight management areas but lower in one area. Measures to promote and protect naturally reproducing populations have been more successful than previously realized.

  6. Development of a multichemical food web model: application to PBDEs in Lake Ellasjoen, Bear Island, Norway.

    Science.gov (United States)

    Gandhi, Nilima; Bhavsar, Satyendra P; Gewurtz, Sarah B; Diamond, Miriam L; Evenset, Anita; Christensen, Guttorm N; Gregor, Dennis

    2006-08-01

    A multichemical food web model has been developed to estimate the biomagnification of interconverting chemicals in aquatic food webs. We extended a fugacity-based food web model for single chemicals to account for reversible and irreversible biotransformation among a parent chemical and transformation products, by simultaneously solving mass balance equations of the chemicals using a matrix solution. The model can be applied to any number of chemicals and organisms or taxonomic groups in a food web. The model was illustratively applied to four PBDE congeners, BDE-47, -99, -100, and -153, in the food web of Lake Ellasjøen, Bear Island, Norway. In Ellasjøen arctic char (Salvelinus alpinus), the multichemical model estimated PBDE biotransformation from higher to lower brominated congeners and improved the correspondence between estimated and measured concentrations in comparison to estimates from the single-chemical food web model. The underestimation of BDE-47, even after considering bioformation due to biotransformation of the otherthree congeners, suggests its formation from additional biotransformation pathways not considered in this application. The model estimates approximate values for congener-specific biotransformation half-lives of 5.7,0.8,1.14, and 0.45 years for BDE-47, -99, -100, and -153, respectively, in large arctic char (S. alpinus) of Lake Ellasjøen. PMID:16913129

  7. Evaluation of the Life History of Native Salmonids in the Malheur River Basin; Cooperative Bull Trout/Redband Trout Research Project, 2002-2003 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Alan; Soupir, Jim (US Forest Service, Prairie City Ranger District, Prairie City, OR); Schwabe, Lawrence (Burns Paiute Tribe, Department of Fish and Wildlife, Burns, OR)

    2003-08-01

    The Malheur River is a 306-kilometer tributary to the Snake River, which drains 12,950 square kilometers. The Malheur River originates in the Blue Mountains and flows into the Snake River near Ontario, Oregon. The climate of the basin is characterized by hot dry summers, occasionally exceeding 38 C, and cold winters that may drop below -29 C. Average annual precipitation is 30 centimeters in the lower reaches. Wooded areas consist primarily of mixed fir and pine forest in the higher elevations. Sagebrush and grass communities dominate the flora in the lower elevations. Efforts to document salmonid life histories, water quality, and habitat conditions have continued in fiscal year 2002. Bull trout Salvelinus confluentus are considered to be cold water species and are temperature-dependant. Due to the interest of bull trout from various state and Federal agencies, a workgroup was formed to develop project objectives related to bull trout. Table 1 lists individuals that participated in the 2002 work group. This report will reflect work completed during the Bonneville Power Administration contract period starting April 1, 2002, and ending March 31, 2003. All tasks were conducted within this timeframe, and a more detailed timeframe may be referred to in each individual report.

  8. Efficiency of Portable Antennas for Detecting Passive Integrated Transponder Tags in Stream-Dwelling Salmonids.

    Directory of Open Access Journals (Sweden)

    Nolan P Banish

    Full Text Available Portable antennas have become an increasingly common technique for tracking fish marked with passive integrated transponder (PIT tags. We used logistic regression to evaluate how species, fish length, and physical habitat characteristics influence portable antenna detection efficiency in stream-dwelling brown trout (Salmo trutta, bull trout (Salvelinus confluentus, and redband trout (Oncorhynchus mykiss newberrii marked with 12-mm PIT tags. We redetected 56% (20/36 of brown trout, 34% (68/202 of bull trout, and 33% (20/61 of redband trout after a recovery period of 21 to 46 hours. Models indicate support for length and species and minor support for percent boulder, large woody debris, and percent cobble as parameters important for describing variation in detection efficiency, although 95% confidence intervals for estimates were large. The odds of detecting brown trout (1.5 ± 2.2 [mean ± SE] are approximately four times as high as bull trout (0.4 ± 1.6 or redband trout (0.3 ± 1.8 and species-specific differences may be related to length. Our reported detection efficiency for brown trout falls within the range of other studies, but is the first reported for bull trout and redband trout. Portable antennas may be a relatively unbiased way of redetecting varying sizes of all three salmonid species.

  9. Accounting for adaptive capacity and uncertainty in assessments of species’ climate-change vulnerability

    Science.gov (United States)

    Wade, Alisa A.; Hand, Brian K.; Kovach, Ryan; Luikart, Gordon; Whited, Diane; Muhlfeld, Clint C.

    2016-01-01

    Climate change vulnerability assessments (CCVAs) are valuable tools for assessing species’ vulnerability to climatic changes, yet failure to include measures of adaptive capacity and to account for sources of uncertainty may limit their effectiveness. Here, we provide a more comprehensive CCVA approach that incorporates all three elements used for assessing species’ climate change vulnerability: exposure, sensitivity, and adaptive capacity. We illustrate our approach using case studies of two threatened salmonids with different life histories – anadromous steelhead trout (Oncorhynchus mykiss) and non-anadromous bull trout (Salvelinus confluentus) – within the Columbia River Basin, USA. We identified general patterns of high vulnerability in low-elevation and southernmost habitats for both species. However, vulnerability rankings varied widely depending on the factors (climate, habitat, demographic, and genetic) included in the CCVA and often differed for the two species at locations where they were sympatric. Our findings illustrate that CCVA results are highly sensitive to data inputs and that spatial differences can complicate multi-species conservation. Our results highlight how CCVAs should be considered within a broader conceptual and computational framework for refining hypotheses, guiding research, and comparing plausible scenarios of species’ vulnerability for ongoing and projected climate change.

  10. Parasites as biological tags of marine, freshwater and anadromous fishes in North America from the Tropics to the Arctic.

    Science.gov (United States)

    Marcogliese, David J; Jacobson, Kym C

    2015-01-01

    Parasites have been considered as natural biological tags of marine fish populations in North America for almost 75 years. In the Northwest Atlantic, the most studied species include Atlantic cod (Gadus morhua), Atlantic herring (Clupea harengus) and the redfishes (Sebastes spp.). In the North Pacific, research has centred primarily on salmonids (Oncorhynchus spp.). However, parasites have been applied as tags for numerous other pelagic and demersal species on both the Atlantic and Pacific coasts. Relatively few studies have been undertaken in the Arctic, and these were designed to discriminate anadromous and resident salmonids (Salvelinus spp.). Although rarely applied in fresh waters, parasites have been used to delineate certain fish stocks within the Great Lakes-St Lawrence River basin. Anisakid nematodes and the copepod Sphyrion lumpi frequently prove useful indicators in the Northwest Atlantic, while myxozoan parasites prove very effective on the coast and open seas of the Pacific Ocean. Relative differences in the ability of parasites to discriminate between fish stocks on the Pacific and Atlantic coasts may be due to oceanographic and bathymetric differences between regions. Molecular techniques used to differentiate populations and species of parasites show promise in future applications in the field.

  11. Fisheries Enhancement on the Coeur d'Alene Indian Reservation; Hangman Creek, Annual Report 2001-2002.

    Energy Technology Data Exchange (ETDEWEB)

    Peters, Ronald; Kinkead, Bruce; Stanger, Mark

    2003-07-01

    Historically, Hangman Creek produced Chinook salmon (Oncorhynchus tshawytscha) and Steelhead trout (Oncorhynchus mykiss) for the Upper Columbia Basin Tribes. One weir, located at the mouth of Hangman Creek was reported to catch 1,000 salmon a day for a period of 30 days a year (Scholz et al. 1985). The current town of Tekoa, Washington, near the state border with Idaho, was the location of one of the principle anadromous fisheries for the Coeur d'Alene Tribe (Scholz et al. 1985). The construction, in 1909, of Little Falls Dam, which was not equipped with a fish passage system, blocked anadromous fish access to the Hangman Watershed. The fisheries were further removed with the construction of Chief Joseph and Grand Coulee Dams. As a result, the Coeur d'Alene Indian Tribe was forced to rely more heavily on native fish stocks such as Redband trout (Oncorhynchus mykiss gairdneri), Westslope Cutthroat trout (O. clarki lewisii), Bull trout (Salvelinus confluentus) and other terrestrial wildlife. Historically, Redband and Cutthroat trout comprised a great deal of the Coeur d'Alene Tribe's diet (Power 1997).

  12. Methanotrophy Induces Nitrogen Fixation in Boreal Mosses

    Science.gov (United States)

    Tiirola, M. A.

    2014-12-01

    Many methanotrophic bacterial groups fix nitrogen in laboratory conditions. Furthermore, nitrogen (N) is a limiting nutrient in many environments where methane concentrations are highest. Despite these facts, methane-induced N fixation has previously been overlooked, possibly due to methodological problems. To study the possible link between methanotrophy and diazotrophy in terrestrial and aquatic habitats, we measured the co-occurrence of these two processes in boreal forest, peatland and stream mosses using a stable isotope labeling approach (15 N2 and 13 CH4 double labeling) and sequencing of the nifH gene marker. N fixation associated with forest mosses was dependent on the annual N deposition, whereas methane stimulate N fixation neither in high (>3 kg N ha -1 yr -1) nor low deposition areas, which was in accordance with the nifH gene sequencing showing that forest mosses (Pleurozium schreberi and Hylocomium splendens ) carried mainly cyanobacterial N fixers. On the other extreme, in stream mosses (Fontinalis sp.) methane was actively oxidized throughout the year, whereas N fixation showed seasonal fluctuation. The co-occurrence of the two processes in single cell level was proven by co-localizing both N and methane-carbon fixation with the secondary ion mass spectrometry (SIMS) approach. Methanotrophy and diazotrophy was also studied in peatlands of different primary successional stages in the land-uplift coast of Bothnian Bay, in the Siikajoki chronosequence, where N accumulation rates in peat profiles indicate significant N fixation. Based on experimental evidence it was counted that methane-induced N fixation explained over one-third of the new N input in the younger peatland successional stages, where the highest N fixation rates and highest methane oxidation activities co-occurred in the water-submerged Sphagnum moss vegetation. The linkage between methanotrophic carbon cycling and N fixation may therefore constitute an important mechanism in the rapid

  13. The linkage between methanotrophy and diazotrophy in boreal environments

    Science.gov (United States)

    Tiirola, Marja; Leppänen, Sanna; Larmola, Tuula; Tuittila, Eeva-Stiina

    2014-05-01

    Many methanotrophic bacterial groups fix nitrogen in laboratory conditions. Furthermore, nitrogen (N) is a limiting nutrient in many environments where methane concentrations are highest. Despite these facts, methane-induced N fixation has previously been overlooked, possibly due to methodological problems. To study the possible link between methanotrophy and diazotrophy in terrestrial and aquatic habitats, we measured the co-occurrence of these two processes in boreal forest, peatland and stream mosses using a stable isotope labeling approach (15N2 and 13CH4 double labeling) and sequencing of the nifH gene marker. N fixation associated with forest mosses was dependent on the annual N deposition, whereas methane stimulate N fixation neither in high (>3 kg N ha-1 yr-1) nor low deposition areas, which was in accordance with the nifH gene sequencing showing that forest mosses (Pleurozium schreberi and Hylocomium splendens) carried mainly cyanobacterial N fixers. On the other extreme, in stream mosses (Fontinalis sp.) methane was actively oxidized throughout the year, whereas N fixation showed seasonal fluctuation. The co-occurrence of the two processes in single cell level was proven by co-localizing both N and methane-carbonfixation with the secondary ion mass spectrometry (SIMS) approach. Methanotrophy and diazotrophy was also studied in peatlands of different primary successional stages in the land-uplift coast of Bothnian Bay, in the Siikajoki chronosequence, where N accumulation rates in peat profiles indicate significant N fixation. Based on experimental evidence it was counted that methane-induced N fixation explained over one-third of the new N input in the younger peatland successional stages, where the highest N fixation rates and highest methane oxidation activities co-occurred in the water-submerged Sphagnum moss vegetation. The linkage between methanotrophic carbon cycling and N fixation may therefore constitute an important mechanism in the rapid

  14. Revision of the American species of the genus Prionus Geoffroy, 1762 (Coleoptera, Cerambycidae, Prioninae, Prionini).

    Science.gov (United States)

    Santos-Silva, Antonio; Nearns, Eugenio H; Swift, Ian P

    2016-01-01

    A revision of the American species of Prionus Geoffroy, 1762 is presented. Prionus (Neopolyarthron) Semenov, 1899 and Prionus (Antennalia) Casey, 1912 are synonymized with Prionus Geoffroy, 1762. Homaesthesis LeConte, 1873 is considered a true subgenus of Prionus. Prionus (Homaesthesis) rhodocerus Linsley, 1957 and Prionus (Homaesthesis) linsleyi Hovore, 1981 are synonymized with Prionus simplex (Casey, 1912). Prionus beauvoisi Lameere, 1915 and Prionus (Neopolyarthron) debilis Casey, 1924 are synonymized with P. imbricornis (Linnaeus, 1767). Prionus (Neopolyarthron) townsendi Casey, 1912 and Prionus (Neopolyarthron) curticollis Casey, 1912 are synonymized with Prionus mexicanus Bates, 1884. Prionus batesi Lameere, 1920 is synonymized with Prionus aztecus Casey, 1912. Prionus hintoni Linsley, 1935 is synonymized with Prionus flohri Bates, 1884. Prionus (Antennalia) fissicornis parviceps Casey, 1912 is excluded as the synonym of Prionus fissicornis Haldeman, 1846 and instead synonymized with P. imbricornis (Linnaeus, 1767). Prionus (Prionus) validiceps Casey, 1912 is excluded from the synonymy of P. pocularis Dalman, 1817, and synonymized with P. (P.) californicus Motschulsky, 1845. Prionus (Prionus) tumidus Casey, 1912 is excluded from the synonymy of P. heroicus Semenov, 1907, and synonymized with P. (P.) californicus. The lectotype female and the paralectotype male of Prionus (Prionus) tristis are excluded from the synonym of P. (P.) heroicus and transferred to the synonym of P. (P.) californicus; the paralectotype female of P. (P.) tristis is maintained in the synonymy of P. (P.) heroicus. Prionus (Prionus) fontinalis Casey, 1914 is excluded from the synonymy of P. (P.) heroicus and synonymized with P. (P.) californicus. Prionus simplex is formally excluded from the Cerambycidae fauna of Oklahoma, USA. Comments on the page, plate, and figure of publication of Cerambyx laticollis Drury, 1773 are presented. Prionus (Trichoprionus) Fragoso & Monné, 1982 is

  15. A Quantitative Polymerase Chain Reaction Assay for the Detection and Quantification of Epizootic Epitheliotropic Disease Virus (EEDV; Salmonid Herpesvirus 3).

    Science.gov (United States)

    Glenney, Gavin W; Barbash, Patricia A; Coll, John A

    2016-03-01

    Epizootic epitheliotropic disease virus (EEDV; salmonid herpesvirus [SalHV3]; family Alloherpesviridae) causes a systemic disease of juvenile and yearling Lake Trout Salvelinus namaycush. No cell lines are currently available for the culture and propagation of EEDV, so primary diagnosis is limited to PCR and electron microscopy. To better understand the pervasiveness of EEDV (carrier or latent state of infection) in domesticated and wild Lake Trout populations, we developed a sensitive TaqMan quantitative PCR (qPCR) assay to detect the presence of the EEDV terminase gene in Lake Trout tissues. This assay was able to detect a linear standard curve over nine logs of plasmid dilution and was sensitive enough to detect single-digit copies of EEDV. The efficiency of the PCR assay was 99.4 ± 0.06% (mean ± SD), with a 95% confidence limit of 0.0296 (R(2) = 0.994). Methods were successfully applied to collect preliminary data from a number of species and water bodies in the states of Pennsylvania, New York, and Vermont, indicating that EEDV is more common in wild fish than previously known. In addition, through the development of this qPCR assay, we detected EEDV in a new salmonid species, the Cisco Coregonus artedi. The qPCR assay was unexpectedly able to detect two additional herpesviruses, the Atlantic Salmon papillomatosis virus (ASPV; SalHV4) and the Namaycush herpesvirus (NamHV; SalHV5), which both share high sequence identity with the EEDV terminase gene. With these unexpected findings, we subsequently designed three primer sets to confirm initial TaqMan qPCR assay positives and to differentiate among EEDV, ASPV, and NamHV by detecting the glycoprotein genes via SYBR Green qPCR. Received April 20, 2015; accepted November 10, 2015.

  16. Decline of shortjaw cisco in Lake Superior: the role of overfishing and risk of extinction

    Science.gov (United States)

    Bronte, Charles R.; Hoff, Michael H.; Gorman, Owen T.; Thogmartin, Wayne E.; Schneeberger, Philip J.; Todd, Thomas N.

    2010-01-01

    Recent reviews have further documented the decline of the shortjaw cisco Coregonus zenithicus in Lake Superior. This fish was the most abundant deepwater cisco species in Lake Superior in the early 1920s but presently makes up less than 1% of all deepwater ciscoes (i.e., including shortjaw cisco, bloater C. hoyi, and kiyi C. kiyi) captured in biological surveys. Directed overfishing of deepwater cisco species during the 1930s and again during the mid-1960s and 1970s has been suggested as the cause of the shortjaw cisco's demise. In this paper, we re-examined the overfishing hypothesis by using historical and recent survey data to estimate the proportion of the historical commercial fishery landings that comprised shortjaw ciscoes. We developed time series of estimated harvest and relative abundance for all statistical districts in Michigan waters of Lake Superior during 1929–1996, for which aggregate catch and effort data were available but not previously examined. The spatial distribution of the fishery and the relationships of catch to fishing effort were examined for evidence of overfishing. Our analysis suggested that directed overfishing was probably not the cause of shortjaw cisco demise, as this species appeared to be declining in all statistical districts regardless of the intensity of the fishery. A count-based population viability analysis indicated that quasi-extinction of the shortjaw cisco is highly probable in the near future. We propose an alternative hypothesis based on the decline of Lake Superior's keystone predator, the lake trout Salvelinus namaycush, which resulted in an expansion of the population of its principal prey, the cisco C. artedi, due to release from predation pressure. Competitive or predation interactions between the cisco and shortjaw cisco may be more likely explanations for the demise of the latter species.

  17. Comparison of three nonlinear models to describe long-term tag shedding by lake trout

    Science.gov (United States)

    Fabrizio, Mary C.; Swanson, Bruce L.; Schram, Stephen T.; Hoff, Michael H.

    1996-01-01

    We estimated long-term tag-shedding rates for lake trout Salvelinus namaycush using two existing models and a model we developed to account for the observed permanence of some tags. Because tag design changed over the course of the study, we examined tag-shedding rates for three types of numbered anchor tags (Floy tags FD-67, FD-67C, and FD-68BC) and an unprinted anchor tag (FD-67F). Lake trout from the Gull Island Shoal region, Lake Superior, were double-tagged, and subsequent recaptures were monitored in annual surveys conducted from 1974 to 1992. We modeled tag-shedding rates, using time at liberty and probabilities of tag shedding estimated from fish released in 1974 and 1978–1983 and later recaptured. Long-term shedding of numbered anchor tags in lake trout was best described by a nonlinear model with two parameters: an instantaneous tag-shedding rate and a constant representing the proportion of tags that were never shed. Although our estimates of annual shedding rates varied with tag type (0.300 for FD-67, 0.441 for FD-67C, and 0.656 for FD-68BC), differences were not significant. About 36% of tags remained permanently affixed to the fish. Of the numbered tags that were shed (about 64%), two mechanisms contributed to tag loss: disintegration and dislodgment. Tags from about 11% of recaptured fish had disintegrated, but most tags were dislodged. Unprinted tags were shed at a significant but low rate immediately after release, but the long-term, annual shedding rate of these tags was only 0.013. Compared with unprinted tags, numbered tags dislodged at higher annual rates; we hypothesized that this was due to the greater frictional drag associated with the larger cross-sectional area of numbered tags.

  18. 鸭绿江花羔红点鲑、细鳞鱼和长白哲罗鱼的繁殖策略比较研究%The Comparative Studies on the Reproductive Strategies of S.malma,B.lenok and H.iskiawai in Yalu River

    Institute of Scientific and Technical Information of China (English)

    黄权; 周景祥; 刘春力; 陈勇

    2001-01-01

    应用生态学方法对鸭绿江花羔红点鲑Salvelinus malma (Wabaum)、细鳞鱼Brachymystax lenok (Pallas)和长白哲罗鱼Hcho ishiawai Mori的繁殖策略进行了研究。结果表明:3 种鱼的繁殖策略表现在初次性成熟年龄和规格、繁殖季节、产卵式型和个体绝对繁殖力方面各不相同,而产卵场及其条件和繁殖方式及行为大致相同,是其自身固有物种特性在同一水域适应生态环境的具体表现,充分发挥了不同鱼类利用同一水域空间、时间和饵料生物的潜力。%The reproductive strategies of S.matma,B.lenok and H.iskiawai in Yalu River were studied by means of biology methods. The result showed that the reproductive strategies including ages and size at sex mature,reproductive season,spawing types and absolute fecundity are different while that spawing ground coiditions, way of reproduction and action are similar.It is showed that special features of different fishes were evoluted to adapt to the ecological environment in the same water body, thus bring into full use of the potentiality of space, season and food organisms of water body in Yalu River by different fishes at the same time.

  19. Biotransformation of polychlorinated biphenyls (PCBs) and bioformation of hydroxylated PCBs in fish

    International Nuclear Information System (INIS)

    Hydroxylated PCBs (OH-PCBs) are a class of organic contaminants that have been found recently in the plasma of Great Lakes fish, the source of which is either bioformation from PCBs or accumulation from the environment. To address the potential for fish to biotransform PCBs and bioform OH-PCBs juvenile rainbow trout (Oncorhynchus mykiss; ∼80 g) were exposed to dietary concentrations of an environmentally relevant mixture of PCBs. Eight OH-PCBs were found in the plasma of rainbow trout after 30 days of exposure to the PCBs, the relative pattern of which was similar to those observed in wild lake trout (Salvelinus namaycush) from Lake Ontario. Hydroxylated-PCBs were not found (detection limit 0.02 pg/g) in the food or control (not PCB-exposed) fish. A curvilinear log t 1/2-log K ow relationship for recalcitrant PCBs was found, similar to previously reported relationships, although t 1/2 values were longer and shorter than studies using smaller fish or cooler temperatures, respectively. A number of PCB congeners fell below the log t 1/2-log K ow relationship providing the first estimates of non-chiral PCB biotransformation rates in fish. Enantioselective degradation of the chiral congeners PCBs 91 and 136, also indicated biotransformation. Biotransformation of PCBs was structure-dependent with greater biotransformation of PCBs with vicinal hydrogen atoms in the meta/para positions, suggesting CYP 2B-like biotransformation. Other chiral congeners with a meta/para substitution pattern showed no enantioselective degradation but were biotransformed based on the log t 1/2-log K ow relationship. The results of this study demonstrate that laboratory held rainbow trout can biotransform a number of PCB congeners and that bioformation is likely an important source of OH-PCBs in wild salmonids of the Great Lakes

  20. Trends of chlorinated organic contaminants in Great Lakes trout and walleye from 1970-1998

    Science.gov (United States)

    Hickey, J.P.; Batterman, S.A.; Chernyak, S.M.

    2006-01-01

    Levels of chlorinated organic contaminants in predator fish have been monitored annually in each of the Great Lakes since the 1970s. This article updates earlier reports with data from 1991 to 1998 for lake trout (Salvelinus namaycush) and (Lake Erie only) walleye (Sander vitreus) to provide a record that now extends nearly 30 years. Whole fish were analyzed for a number of industrial contaminants and pesticides, including polychlorinated biphenyls (PCBs), dichloro-diphenyl-trichloroethane (DDT), dieldrin, toxaphene, and mirex, and contaminant trends were quantified using multicompartment models. As in the past, fish from Lakes Michigan, Ontario, and Huron have the highest levels of PCBs, DDT, and dieldrin; Superior has the highest levels of toxaphene; and Ontario has the highest levels of mirex. In the period after curtailment of chemical use, concentrations rapidly decreased, represented by relatively short half-lives from approximately 1 to 9 years. Although trends depend on both the contaminant and the lake, in many cases the rate of decline has been decreasing, and concentrations are gradually approaching an irreducible concentration. For dioxin-like PCBs, levels have not been decreasing during the most recent 5-year period (1994 to 1998). In some cases, the year-to-year variation in contaminant levels is large, mainly because of food-web dynamics. Although this variation sometimes obscures long-term trends, the general pattern of a rapid decrease followed by slowing or leveling-off of the downward trend seems consistent across the Great Lakes, and future improvements of the magnitude seen in the 1970s and early 1980s likely will take much longer.

  1. The Microbiota of Freshwater Fish and Freshwater Niches Contain Omega-3 Fatty Acid-Producing Shewanella Species.

    Science.gov (United States)

    Dailey, Frank E; McGraw, Joseph E; Jensen, Brittany J; Bishop, Sydney S; Lokken, James P; Dorff, Kellen J; Ripley, Michael P; Munro, James B

    2016-01-01

    Approximately 30 years ago, it was discovered that free-living bacteria isolated from cold ocean depths could produce polyunsaturated fatty acids (PUFA) such as eicosapentaenoic acid (EPA) (20:5n-3) or docosahexaenoic acid (DHA) (22:6n-3), two PUFA essential for human health. Numerous laboratories have also discovered that EPA- and/or DHA-producing bacteria, many of them members of the Shewanella genus, could be isolated from the intestinal tracts of omega-3 fatty acid-rich marine fish. If bacteria contribute omega-3 fatty acids to the host fish in general or if they assist some bacterial species in adaptation to cold, then cold freshwater fish or habitats should also harbor these producers. Thus, we undertook a study to see if these niches also contained omega-3 fatty acid producers. We were successful in isolating and characterizing unique EPA-producing strains of Shewanella from three strictly freshwater native fish species, i.e., lake whitefish (Coregonus clupeaformis), lean lake trout (Salvelinus namaycush), and walleye (Sander vitreus), and from two other freshwater nonnative fish, i.e., coho salmon (Oncorhynchus kisutch) and seeforellen brown trout (Salmo trutta). We were also able to isolate four unique free-living strains of EPA-producing Shewanella from freshwater habitats. Phylogenetic and phenotypic analyses suggest that one producer is clearly a member of the Shewanella morhuae species and another is sister to members of the marine PUFA-producing Shewanella baltica species. However, the remaining isolates have more ambiguous relationships, sharing a common ancestor with non-PUFA-producing Shewanella putrefaciens isolates rather than marine S. baltica isolates despite having a phenotype more consistent with S. baltica strains. PMID:26497452

  2. Kootenai River Fisheries Investigations: Salmonid Studies Project Progress Report, 2007-2008 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Paragamian, Vaughn L.; Walters, Jody; Maiolie, Melo [Idaho Department of Fish and Game

    2009-04-09

    This research report addresses bull trout Salvelinus confluentus and Redband trout Oncorhynchus mykiss redd surveys, population monitoring, trout distribution, and abundance surveys in the Kootenai River drainage of Idaho. The bull trout is one of several sport fish native to the Kootenai River, Idaho that no longer supports a fishery. Because bull trout are listed under the Endangered Species Act, population data will be vital to monitoring status relative to recovery goals. Thirty-three bull trout redds were found in North and South Callahan creeks and Boulder Creek in 2007. This is a decrease from 2006 and 2005 and less than the high count in 2003. However, because redd numbers have only been monitored since 2002, the data series is too short to determine bull trout population trends based on redd counts. Redband trout still provide an important Kootenai River sport fishery, but densities are low, at least partly due to limited recruitment. The redband trout proportional stock density (PSD) in 2007 increased from 2006 for a second year after a two-year decline in 2004 and 2005. This may indicate increased recruitment to or survival in the 201-305 mm length group due to the minimum 406 mm (16 inches) length limit initiated in 2002. We conducted 13 redd surveys and counted 44 redband trout redds from May 7 to June 3, 2007 in a 3.8 km survey reach on Twentymile Creek. We surveyed streams in the Kootenai River valley to look for barriers to trout migration. Man-made barriers, for at least part of the year, were found on Caboose, Debt, Fisher, and Twenty Mile creeks. Removing these barriers would increase spawning and rearing habitat for trout and help to restore trout fisheries in the Kootenai River.

  3. Relative abundance, site fidelity, and survival of adult lake trout in Lake Michigan from 1999 to 2001: Implications for future restoration strategies

    Science.gov (United States)

    Bronte, C.R.; Holey, M.E.; Madenjian, C.P.; Jonas, J.L.; Claramunt, R.M.; McKee, P.C.; Toneys, M.L.; Ebener, M.P.; Breidert, B.; Fleischer, G.W.; Hess, R.; Martell, A.W.; Olsen, E.J.

    2007-01-01

    We compared the relative abundance of lake trout Salvelinus namaycush spawners in gill nets during fall 1999–2001 in Lake Michigan at 19 stocked spawning sites with that at 25 unstocked sites to evaluate how effective site-specific stocking was in recolonizing historically important spawning reefs. The abundance of adult fish was higher at stocked onshore and offshore sites than at unstocked sites. This suggests that site-specific stocking is more effective at establishing spawning aggregations than relying on the ability of hatchery-reared lake trout to find spawning reefs, especially those offshore. Spawner densities were generally too low and too young at most sites to expect significant natural reproduction. However, densities were sufficiently high at some sites for reproduction to occur and therefore the lack of recruitment was attributable to other factors. Less than 3% of all spawners could have been wild fish, which indicates that little natural reproduction occurred in past years. Wounding by sea lamprey Petromyzon marinus was generally lower for Seneca Lake strain fish and highest for strains from Lake Superior. Fish captured at offshore sites in southern Lake Michigan had the lowest probability of wounding, while fish at onshore sites in northern Lake Michigan had the highest probability. The relative survival of the Seneca Lake strain was higher than that of the Lewis Lake or the Marquette strains for the older year-classes examined. Survival differences among strains were less evident for younger year-classes. Recaptures of coded-wire-tagged fish of five strains indicated that most fish returned to their stocking site or to a nearby site and that dispersal from stocking sites during spawning was about 100 km. Restoration strategies should rely on site-specific stocking of lake trout strains with good survival at selected historically important offshore spawning sites to increase egg deposition and the probability of natural reproduction in Lake

  4. Climate change expands the spatial extent and duration of preferred thermal habitat for lake Superior fishes.

    Directory of Open Access Journals (Sweden)

    Timothy J Cline

    Full Text Available Climate change is expected to alter species distributions and habitat suitability across the globe. Understanding these shifting distributions is critical for adaptive resource management. The role of temperature in fish habitat and energetics is well established and can be used to evaluate climate change effects on habitat distributions and food web interactions. Lake Superior water temperatures are rising rapidly in response to climate change and this is likely influencing species distributions and interactions. We use a three-dimensional hydrodynamic model that captures temperature changes in Lake Superior over the last 3 decades to investigate shifts in habitat size and duration of preferred temperatures for four different fishes. We evaluated habitat changes in two native lake trout (Salvelinus namaycush ecotypes, siscowet and lean lake trout, Chinook salmon (Oncorhynchus tshawytscha, and walleye (Sander vitreus. Between 1979 and 2006, days with available preferred thermal habitat increased at a mean rate of 6, 7, and 5 days per decade for lean lake trout, Chinook salmon, and walleye, respectively. Siscowet lake trout lost 3 days per decade. Consequently, preferred habitat spatial extents increased at a rate of 579, 495 and 419 km(2 per year for the lean lake trout, Chinook salmon, and walleye while siscowet lost 161 km(2 per year during the modeled period. Habitat increases could lead to increased growth and production for three of the four fishes. Consequently, greater habitat overlap may intensify interguild competition and food web interactions. Loss of cold-water habitat for siscowet, having the coldest thermal preference, could forecast potential changes from continued warming. Additionally, continued warming may render more suitable conditions for some invasive species.

  5. Walla Walla River Fish Passage Operations Program, 2000-2001 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Zimmerman, Brian C. (Confederated Tribes of the Umatilla Indian Reservation, Department of Natural Resources, Pendleton, OR); Duke, Bill B. (Oregon Department of Fish and Wildlife, Pendleton, OR)

    2004-02-01

    In the late 1990's, the Confederated Tribes of the Umatilla Indian Reservation, Oregon Department of Fish and Wildlife, and Washington Department of Fish and Wildlife, along with many other agencies, began implementing fisheries restoration activities in the Walla Walla Basin. An integral part of these efforts is to alleviate the inadequate migration conditions in the basin. The migration concerns are being addressed by removing diversion structures, constructing fish passage facilities, implementing minimum instream flow measures, and initiating trap and haul efforts. The objective of the Walla Walla River Fish Passage Operations Project is to increase the survival of migrating adult and juvenile salmonids in the basin. The project is responsible for coordinating operation and maintenance of ladders, screen sites, bypasses, trap facilities, and transportation equipment. In addition, the project provides technical input on passage criteria and passage and trapping facility design and operation. Operation of the various passage facilities and passage criteria guidelines are outlined in an annual operations plan that the project develops. During the 2000-2001 project year, there were 624 summer steelhead (Oncorhynchus mykiss), 24 bull trout (Salvelinus confluentus), and 47 spring chinook (O. tshawytscha) counted at the Nursery Bridge Dam adult trap between December 27, 2000 and June 7, 2001. The Little Walla Walla River juvenile trap was not operated this year. The project transported 1600 adult spring chinook from Ringold Springs Hatchery to the South Fork Walla Walla Brood Holding Facility and outplanted 1156 for natural spawning in the basin. The project also provided equipment for transportation of juveniles captured during the construction fish salvage at Nursery Bridge Dam.

  6. Maternal characteristics versus egg size and energy density: do stocked lake trout in Lake Ontario experience premature reproductive senescence?

    Science.gov (United States)

    Lantry, B.F.; O'Gorman, R.; Machut, L.S.

    2008-01-01

    Observations from September 1994 and 1997 collections of hatchery-origin, mature female lake trout (Salvelinus namaycush) from Lake Ontario indicated that egg mass decreased with age, fueling the notion that stocked fish experienced premature reproductive senescence. Supplemental collections during September 2002 and November 2002-2004 were combined with the 1994 and 1997 samples to examine whether sample date or maternal age, body mass, condition (K), egg count, or strain were related to egg mass or energy content (percentage dry mass [%DM]). Body mass was correlated with egg mass for age ≥ 8 lake trout sampled in September, and egg count was correlated with egg mass for September age-6 lake trout only. Within each month, egg mass was not related to K or egg %DM, however, egg %DM was 1.52% greater (P ≤ 0.0247) in November than in September which is equivalent to a 110 cal/g difference. Samples were grouped for the three most abundant strains (Seneca, Superior, and Ontario) after finding no strain or year effects from our 1994 and 1997 samples and based on life history data from the literature and our assessment sampling. Further analysis indicated that September egg masses were greater for fish ages ≤ 6 than for fish ages ≥ 8. The age effect disappeared in November when mean egg mass across all ages (0.078 g) was greater than September means (P < 0.0005) for ages -5 (0.054 g), -6 (0.057 g) and ≥ 8 (0.041 g). Our results indicate that the decrease in egg mass with female age in September was not due to senescence, but to oogenesis being closer to completion in young age-5 and -6 fish than in older individuals.

  7. Use of a seismic air gun to reduce survival of nonnative lake trout embryos: A tool for conservation?

    Science.gov (United States)

    Cox, B.S.; Dux, A.M.; Quist, M.C.; Guy, C.S.

    2012-01-01

    The detrimental impacts of nonnative lake trout Salvelinus namaycush in the western USA have prompted natural resource management agencies in several states to implement lake trout suppression programs. Currently, these programs rely on mechanical removal methods (i.e., gill nets, trap nets, and angling) to capture subadult and adult lake trout. We conducted a study to explore the potential for using high-intensity sound from a relatively small (655.5 cm3 [40 in3]) seismic air gun to reduce survival of lake trout embryos. Lake trout embryos at multiple stages of development were exposed to a single discharge of the seismic air gun at two depths (5 and 15 m) and at two distances from the air gun (0.1 and 2.7 m). Control groups for each developmental stage, distance, and depth were treated identically except that the air gun was not discharged. Mortality in lake trout embryos treated at 0.1 m from the air gun was 100% at 74 daily temperature units in degrees Celsius (TU°C) at both depths. Median mortality in lake trout embryos treated at 0.1 m from the air gun at 207 TU°C (93%) and 267 °C (78%) appeared to be higher than that of controls (49% and 48%, respectively) at 15-m depth. Among the four lake trout developmental stages, exposure to the air gun at 0.1 m resulted in acute mortality up to 60% greater than that of controls. Mortality at a distance of 2.7 m did not appear to differ from that of controls at any developmental stage or at either depth. Our results indicate that seismic air guns have potential as an alternative tool for controlling nonnative lake trout, but further investigation is warranted.

  8. Kootenai River Fisheries Investigations; Rainbow and Bull Trout Recruitment, 1999 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Walters, Jody P.; Downs, Christopher C.

    2001-08-01

    Our 1999 objectives were to determine sources of rainbow trout Oncorhynchus mykiss and bull trout Salvelinus confluentus spawning and recruitment in the Idaho reach of the Kootenai River. We used a rotary-screw trap to capture juvenile trout to determine age at out-migration and to estimate total out-migration from the Boundary Creek drainage to the Kootenai River. The out-migrant estimate for March through August 1999 was 1,574 (95% C. I. = 825-3,283) juvenile rainbow trout. Most juveniles out-migrated at age-2 and age-3. No out-migrating bull trout were caught. Five of 17 rainbow trout radio-tagged in Idaho migrated upstream into Montana waters during the spawning season. Five bull trout originally radio-tagged in O'Brien Creek, Montana in early October moved downstream into Idaho and British Columbia by mid-October. Annual angler exploitation for the rainbow trout population upstream of Bonners Ferry, Idaho was estimated to be 58%. Multi-pass depletion estimates for index reaches of Caboose, Curley, and Debt creeks showed 0.20, 0.01, and 0.13 rainbow trout juveniles/m{sup 2}, respectively. We estimated rainbow trout (180-415 mm TL) standing stock of 1.6 kg/ha for the Hemlock Bar reach (29.4 ha) of the Kootenai River, similar to the 1998 estimate. Recruitment of juvenile rainbow and bull trout from Idaho tributaries is not sufficient to be the sole source of subsequent older fish in the mainstem Kootenai River. These populations are at least partly dependent on recruitment from Montana waters. The low recruitment and high exploitation rate may be indicators of a rainbow trout population in danger of further decline.

  9. Trophic transfer of persistent organochlorine contaminants (OCs) within an Arctic marine food web from the southern Beaufort-Chukchi Seas

    International Nuclear Information System (INIS)

    The trophic status and biomagnification of persistent OCs within the near-shore Beaufort-Chukchi Seas food web from Barrow, AK is discussed. - Stable isotope values (δ13C, δ15N) and concentrations of persistent organochlorine contaminants (OCs) were determined to evaluate the near-shore marine trophic status of biota and biomagnification of OCs from the southern Beaufort-Chukchi Seas (1999-2000) near Barrow, AK. The biota examined included zooplankton (Calanus spp.), fish species such as arctic cod (Boreogadus saida), arctic char (Salvelinus alpinus), pink salmon (Oncorhynchus gorbuscha), and fourhorn sculpin (Myoxocephalus quadricornis), along with marine mammals, including bowhead whales (Balaena mysticetus), beluga whales (Delphinapterus leucas), ringed seals (Phoca hispida) and bearded seals (Erignathus barbatus). The isotopically derived trophic position of biota from the Beaufort-Chukchi Seas marine food web, avian fauna excluded, is similar to other coastal food webs in the Arctic. Concentrations of OCs in marine mammals were significantly greater than in fish and corresponded with determined trophic level. In general, OCs with the greatest food web magnification factors (FWMFs) were those either formed due to biotransformation (e.g. p,p'-DDE, oxychlordane) or considered recalcitrant (e.g. β-HCH, 2,4,5-Cl substituted PCBs) in most biota, whereas concentrations of OCs that are considered to be readily eliminated (e.g. γ-HCH) did not correlate with trophic level. Differences in physical-chemical properties of OCs, feeding strategy and possible biotransformation were reflected in the variable biomagnification between fish and marine mammals. The FWMFs in the Beaufort-Chukchi Seas region were consistent with reported values in the Canadian Arctic and temperate food webs, but were statistically different than FWMFs from the Barents and White Seas, indicating that the spatial variability of OC contamination in top-level marine Arctic predators is attributed to

  10. Rodent neurotoxicity bioassays for screening contaminated Great Lakes fish

    Energy Technology Data Exchange (ETDEWEB)

    Beattie, M.K.; Hoffman, R. [Univ. of Minnesota, Duluth, MN (United States); Gerstenberger, S. [Univ. of Illinois, Urbana, IL (United States). Dept. of Veterinary Biosciences; Dellinger, J.A. [Medical Coll. of Wisconsin, Milwaukee, MI (United States). Dept. of Preventive Medicine

    1996-03-01

    Standard laboratory rat neurotoxicity protocols were used to study the consequences resulting from the consumption of walleye (Stizostedion vitreum), whitefish (Coregonus clupeaformis), and lake trout (Salvelinus namaycush) from Lake Superior (LS) and the consumption of carp (Cyprinus carpio) from Little Lake Butte des Morte (LLBM) near Oshkosh, Wisconsin, USA. Two 90-d subchronic studies are described, including a 45-d exposure to fish diets using male Sprague-Dawley hooded rats, and a 90-d exposure to fish diets using female rats of the same species. Behavioral alterations were tested using a battery of behavioral tests. In addition, pharmacologic challenges using apomorphine and D-amphetamine were administered to the rats to reveal latent neurotoxic effects. Cumulative fish consumption data were recorded daily, weight gain recorded weekly, and behavior data collected prior to exposure, and on days 7, 14, 55 {+-} 2, 85 {+-} 2. Motor activity data were collected on days 30 {+-} 2, 60 {+-} 2, and 90 {+-} 2 of the feeding protocols. Brain tissue from rodents fed these fish were subsequently analyzed for either mercury (Hg) or polychlorinated biphenyls (PCB). Mercury concentrations were increased in the brains of the walleye-fed rats, and PCB concentrations ranged from 0.5 nl/L to 10 nl/L in the brains of rats fed carp from LLBM, a Lake Michigan tributary. Adult male rats fed LLBM carp for 45 d exhibited the greatest behavior responses to the dopaminergic agonist apomorphine on the accelerating rotarod, although these differences were not significant. The 90-d exposure of LS walleye or Hg-spiked LS walleye resulted in behavior alterations on tactile startle response and second footsplay. D-Amphetamine challenge caused changes in tactile startle response, second footsplay, and accelerating rotarod performance after consuming walleye diets. Rats fed LLBM carp had altered behavioral responses to apomorphine on the accelerating rotarod.

  11. Relationships between water temperatures and upstream migration, cold water refuge use, and spawning of adult bull trout from the Lostine River, Oregon, USA

    Science.gov (United States)

    Howell, P.J.; Dunham, J.B.; Sankovich, P.M.

    2010-01-01

    Understanding thermal habitat use by migratory fish has been limited by difficulties in matching fish locations with water temperatures. To describe spatial and temporal patterns of thermal habitat use by migratory adult bull trout, Salvelinus confluentus, that spawn in the Lostine River, Oregon, we employed a combination of archival temperature tags, radio tags, and thermographs. We also compared temperatures of the tagged fish to ambient water temperatures to determine if the fish were using thermal refuges. The timing and temperatures at which fish moved upstream from overwintering areas to spawning locations varied considerably among individuals. The annual maximum 7-day average daily maximum (7DADM) temperatures of tagged fish were 16-18 ??C and potentially as high as 21 ??C. Maximum 7DADM ambient water temperatures within the range of tagged fish during summer were 18-25 ??C. However, there was no evidence of the tagged fish using localized cold water refuges. Tagged fish appeared to spawn at 7DADM temperatures of 7-14 ??C. Maximum 7DADM temperatures of tagged fish and ambient temperatures at the onset of the spawning period in late August were 11-18 ??C. Water temperatures in most of the upper Lostine River used for spawning and rearing appear to be largely natural since there has been little development, whereas downstream reaches used by migratory bull trout are heavily diverted for irrigation. Although the population effects of these temperatures are unknown, summer temperatures and the higher temperatures observed for spawning fish appear to be at or above the upper range of suitability reported for the species. Published 2009. This article is a US Governmentwork and is in the public domain in the USA.

  12. Biochemistry and metabolism of lake trout: laboratory and field studies on the effects of contaminants

    Science.gov (United States)

    Passino, Dora R. May

    1981-01-01

    To evaluate the effects of ambient and higher concentrations of PCB's (Aroclor 1254) and DDE in food and water on fry of lake trout (Salvelinus namaycush) from Lake Michigan, I measured several biochemical indicators of stress in exposed and unexposed (control) fry. No differences between treatments were observed in oxygen consumption rates or lactate concentrations of unexercised fry, but apparent differences in specific swimming speed and lactate response in fry that swam to exhaustion suggested that exposed fry had lower stamina. Observed differences between biochemical profiles of 1-day-old sac fry reared from eggs originating from lake trout collected off Saugatuck and those originating from eggs of brood stock at the Marquette (Michigan) hatchery may have been caused by organochlorine contamination or by genetic and dietary differences between the parental stocks. Activity of the enzyme allantoinase was measured in juvenile and adult lake trout as an indicator of sublethal effects of Great Lakes contaminants. The 50% inhibition of allantoinase in vitro occurred at 6.0 mg/L Cu++, 6.7 mg/L Cd++, 34 mg/L Hg++, and 52 mg/L Pb++. Allantoinase was not affected by in vitro exposure to PCB's up to 7 μg/g, or DDE or DDT up to 10 μg/g; however, in vivo exposure resulting in 2.6 μg/g PCB's in the whole fish activated allantoinase slightly (10% significance level). Allantoinase activity was negatively correlated with total length for fish from Lake Michigan but not for fish from Lake Superior or from laboratory stocks. Mercury, PCB's, and DDT, possibly acting in combination with each other and with additional contaminants, may be the cause of the negative correlation of allantoinase activity with size in Lake Michigan lake trout.

  13. Long-term impacts of invasive species on a native top predator in a large lake system

    Science.gov (United States)

    Rush, Scott A.; Paterson, Gordon; Johnson, Tim B.; Drouillard, Ken G.; Haffner, Gordon D.; Hebert, Craig E.; Arts, Michael T.; McGoldrick, Daryl J.; Backus, Sean M.; Lantry, Brian F.; Lantry, Jana R.; Schaner, Ted; Fisk, Aaron T.

    2012-01-01

    1. Declining abundances of forage fish and the introduction and establishment of non-indigenous species have the potential to substantially alter resource and habitat exploitation by top predators in large lakes. 2. We measured stable isotopes of carbon (δ13C) and nitrogen (δ15N) in field-collected and archived samples of Lake Ontario lake trout (Salvelinus namaycush) and five species of prey fish and compared current trophic relationships of this top predator with historical samples. 3. Relationships between δ15N and lake trout age were temporally consistent throughout Lake Ontario and confirmed the role of lake trout as a top predator in this food web. However, δ13C values for age classes of lake trout collected in 2008 ranged from 1.0 to 3.9‰ higher than those reported for the population sampled in 1992. 4. Isotope mixing models predicted that these changes in resource assimilation were owing to the replacement of rainbow smelt (Osmerus mordax) by round goby (Neogobius melanostomus) in lake trout diet and increased reliance on carbon resources derived from nearshore production. This contrasts with the historical situation in Lake Ontario where δ13C values of the lake trout population were dominated by a reliance on offshore carbon production. 5. These results indicate a reduced capacity of the Lake Ontario offshore food web to support the energetic requirements of lake trout and that this top predator has become increasingly reliant on prey resources that are derived from nearshore carbon pathways.

  14. Combining demographic and genetic factors to assess population vulnerability in stream species

    Science.gov (United States)

    Erin L, Landguth; Muhlfeld, Clint C.; Jones, Leslie W.; Waples, Robin S.; Whited, Diane; Lowe, Winsor H.; Lucotch, John; Neville, Helen; Luikart, Gordon

    2014-01-01

    Accelerating climate change and other cumulative stressors create an urgent need to understand the influence of environmental variation and landscape features on the connectivity and vulnerability of freshwater species. Here, we introduce a novel modeling framework for aquatic systems that integrates spatially explicit, individual-based, demographic and genetic (demogenetic) assessments with environmental variables. To show its potential utility, we simulated a hypothetical network of 19 migratory riverine populations (e.g., salmonids) using a riverscape connectivity and demogenetic model (CDFISH). We assessed how stream resistance to movement (a function of water temperature, fluvial distance, and physical barriers) might influence demogenetic connectivity, and hence, population vulnerability. We present demographic metrics (abundance, immigration, and change in abundance) and genetic metrics (diversity, differentiation, and change in differentiation), and combine them into a single vulnerability index for identifying populations at risk of extirpation. We considered four realistic scenarios that illustrate the relative sensitivity of these metrics for early detection of reduced connectivity: (1) maximum resistance due to high water temperatures throughout the network, (2) minimum resistance due to low water temperatures throughout the network, (3) increased resistance at a tributary junction caused by a partial barrier, and (4) complete isolation of a tributary, leaving resident individuals only. We then applied this demogenetic framework using empirical data for a bull trout (Salvelinus confluentus) metapopulation in the upper Flathead River system, Canada and USA, to assess how current and predicted future stream warming may influence population vulnerability. Results suggest that warmer water temperatures and associated barriers to movement (e.g., low flows, dewatering) are predicted to fragment suitable habitat for migratory salmonids, resulting in the loss

  15. Quantitative polymerase chain reaction (PCR) assays for a bacterial thiaminase I gene and the thiaminase-producing bacterium Paenibacillus thiaminolyticus.

    Science.gov (United States)

    Richter, C.A.; Wright-Osment, Maureen K.; Zajicek, J.L.; Honeyfield, D.C.; Tillitt, D.E.

    2009-01-01

    The thiaminase I enzyme produced by the gram-positive bacterium Paenibacillus thiaminolyticus isolated from the viscera of Lake Michigan alewives Alosa pseudoharengus is currently the only defined source of the thiaminase activity linked to thiamine (vitamin B1) deficiency in early mortality syndrome (EMS) in the larvae of Great Lakes salmonines. Diets of alewife or isolated strains of P. thiaminolyticus mixed in a semipurified diet and fed to lake trout Salvelinus namaycush have been shown to produce EMS in fry. We utilized quantitative polymerase chain reaction (Q-PCR) to aid in studies of the sources of P. thiaminolyticus and thiaminase I. Quantitative PCR assays were established to detect the thiaminase I gene of P. thiaminolyticus, the 16S rRNA gene from most species of bacteria, and the 16S rRNA gene specifically from P. thiaminolyticus and a few closely related taxa. The Q-PCR assays are linear over at least six orders of magnitude and can detect the thiaminase I gene of P. thiaminolyticus from as few as 1,000 P. thiaminolyticus cells/g of sample or the Paenibacillus 16S rRNA gene from as few as 100 P. thiaminolyticus cells/g of sample. The initial results from alewife viscera samples with high thiaminase activity yielded unexpectedly low densities of P. thiaminolyticus cells; Paenibacillus thiaminolyticus was detectable in 2 of 6 alewife viscera tested at densities on the order of 100 cells/g out of 100,000,000 total bacterial cells/g. The low numbers of P. thiaminolyticus detected suggest that alewives contain additional non-P. thiaminolyticus sources of thiaminase activity.

  16. Bull Trout Life History, Genetics, Habitat Needs, and Limiting Factors in Central and Northeast Oregon, Annual Report 2000.

    Energy Technology Data Exchange (ETDEWEB)

    Hemmingsen, Alan R.; Gunckel, Stephanie L.; Sankovich, Paul M.; Howell, Philip J.

    2001-11-01

    This section describes work accomplished in 2000 that continued to address two objectives of this project. These objectives are (1) determine the distribution of juvenile and adult bull trout Salvelinus confluentus and habitats associated with that distribution, and (2) determine fluvial and resident bull trout life history patterns. Completion of these objectives is intended through studies of bull trout in the Grande Ronde, Walla Walla, and John Day basins. These basins were selected because they provide a variety of habitats, from relatively degraded to pristine, and bull trout populations were thought to vary from relatively depressed to robust. In all three basins we continued to monitor the movements of bull trout with radio transmitters applied in 1998 (Hemmingsen, Bellerud, Gunckel and Howell 2001) and 1999 (Hemmingsen, Gunckel and Howell 2001). No new radio transmitters were applied to bull trout of the upper John Day River subbasin, Mill Creek (Walla Walla Basin), or the Grande Ronde Basin in 2000. We did implant radio transmitters in two bull trout incidentally captured in the John Day River near the confluence of the North Fork John Day River. In Mill Creek, we used traps to capture migrant bull trout to obtain data for the third successive year in this stream. With these traps, we intended to determine the timing of bull trout movements both upstream and downstream, and to determine the relative abundance, size and age of migrant fish. Because we captured migrant bull trout with traps for three years in the upper John Day River and its tributaries (Hemmingsen, Bellerud, Buchanan, Gunckel, Shappart and Howell 2001; Hemmingsen, Bellerud, Gunckel and Howell 2001; Hemmingsen, Gunckel and Howell 2001) and traps were no longer needed to capture bull trout for radio-tagging, no traps were operated in the John Day Basin in 2000.

  17. A Quantitative Polymerase Chain Reaction Assay for the Detection and Quantification of Epizootic Epitheliotropic Disease Virus (EEDV; Salmonid Herpesvirus 3).

    Science.gov (United States)

    Glenney, Gavin W; Barbash, Patricia A; Coll, John A

    2016-03-01

    Epizootic epitheliotropic disease virus (EEDV; salmonid herpesvirus [SalHV3]; family Alloherpesviridae) causes a systemic disease of juvenile and yearling Lake Trout Salvelinus namaycush. No cell lines are currently available for the culture and propagation of EEDV, so primary diagnosis is limited to PCR and electron microscopy. To better understand the pervasiveness of EEDV (carrier or latent state of infection) in domesticated and wild Lake Trout populations, we developed a sensitive TaqMan quantitative PCR (qPCR) assay to detect the presence of the EEDV terminase gene in Lake Trout tissues. This assay was able to detect a linear standard curve over nine logs of plasmid dilution and was sensitive enough to detect single-digit copies of EEDV. The efficiency of the PCR assay was 99.4 ± 0.06% (mean ± SD), with a 95% confidence limit of 0.0296 (R(2) = 0.994). Methods were successfully applied to collect preliminary data from a number of species and water bodies in the states of Pennsylvania, New York, and Vermont, indicating that EEDV is more common in wild fish than previously known. In addition, through the development of this qPCR assay, we detected EEDV in a new salmonid species, the Cisco Coregonus artedi. The qPCR assay was unexpectedly able to detect two additional herpesviruses, the Atlantic Salmon papillomatosis virus (ASPV; SalHV4) and the Namaycush herpesvirus (NamHV; SalHV5), which both share high sequence identity with the EEDV terminase gene. With these unexpected findings, we subsequently designed three primer sets to confirm initial TaqMan qPCR assay positives and to differentiate among EEDV, ASPV, and NamHV by detecting the glycoprotein genes via SYBR Green qPCR. Received April 20, 2015; accepted November 10, 2015. PMID:26980561

  18. Feeding ecology of native and nonnative salmonids during the expansion of a nonnative apex predator in Yellowstone Lake, Yellowstone National Park

    Science.gov (United States)

    Syslo, John M.; Guy, Christopher S.; Koel, Todd M.

    2016-01-01

    The illegal introduction of Lake Trout Salvelinus namaycush into Yellowstone Lake, Yellowstone National Park, preceded the collapse of the native population of Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri, producing a four-level trophic cascade. The Yellowstone Cutthroat Trout population’s collapse and the coinciding increase in Lake Trout abundance provided a rare opportunity to evaluate the feeding ecology of a native prey species and a nonnative piscivore species after the restructuring of a large lentic ecosystem. We assessed diets, stable isotope signatures, and depth-related CPUE patterns for Yellowstone Cutthroat Trout and Lake Trout during 2011–2013 to evaluate trophic overlap. To evaluate diet shifts related to density, we also compared 2011–2013 diets to those from studies conducted during previous periods with contrasting Yellowstone Cutthroat Trout and Lake Trout CPUEs. We illustrate the complex interactions between predator and prey in a simple assemblage and demonstrate how a nonnative apex predator can alter competitive interactions. The diets of Yellowstone Cutthroat Trout were dominated by zooplankton during a period when the Yellowstone Cutthroat Trout CPUE was high and were dominated by amphipods when the CPUE was reduced. Lake Trout shifted from a diet that was dominated by Yellowstone Cutthroat Trout during the early stages of the invasion to a diet that was dominated by amphipods after Lake Trout abundance had increased and after Yellowstone Cutthroat Trout prey had declined. The shifts in Yellowstone Cutthroat Trout and Lake Trout diets resulted in increased trophic similarity of these species through time due to their shared reliance on benthic amphipods. Yellowstone Cutthroat Trout not only face the threat posed by Lake Trout predation but also face the potential threat of competition with Lake Trout if amphipods are limiting. Our results demonstrate the importance of studying the long-term feeding ecology of fishes in

  19. Total mercury concentrations in anadromous Northern Dolly Varden from the northwestern Canadian Arctic: A historical baseline study

    Energy Technology Data Exchange (ETDEWEB)

    Tran, L., E-mail: l5tran@uwaterloo.ca [Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Reist, J.D. [Fisheries and Oceans Canada, Winnipeg, Manitoba R3T 2N6 (Canada); Power, M., E-mail: m3power@uwaterloo.ca [Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada)

    2015-03-15

    Previous research has documented the significance of total mercury (THg) as a northern contaminant in general and of fish in particular. While much research has been devoted to documenting both spatial and temporal changes in THg in consumed fish, little effort has been directed at understanding patterns of THg in Dolly Varden (Salvelinus malma), a prized subsistence species throughout the western North American Arctic. Here we report historical THg concentrations for anadromous Dolly Varden from 10 populations in the Yukon and Northwest Territories sampled across a range of latitudes (67–69°N) and longitudes (136–141°W) between the years 1988–91. Unadjusted mean THg concentrations ranged from 15 to 254 ng/g wet weight. Length-adjusted THg concentrations were significantly different among sites, but were not related to latitude or longitude. Within and among populations, THg was significantly related to fork-length, age, δ{sup 15}N, and δ{sup 13}C, with the variation in THg found among populations being best explained by size. The data serve as an important baseline against which future changes in THg levels in this important subsistence fishery may be compared to determine the significance of any observed trends. - Highlights: • THg were measured in Dolly Varden from the Yukon and Northwest Territories. • Length-adjusted THg concentrations were not related to latitude or longitude. • Among-population variation in THg was best explained by fork-length. • Length-adjusted THg concentrations were related to age, δ{sup 15}N, and δ{sup 13}C. • Mean THg were below Health Canada’s consumption guideline for commercial fish.

  20. Egg thiamine status of Lake Ontario salmonines 1995-2004 with emphasis on lake trout

    Science.gov (United States)

    Fitzsimons, J.D.; Williston, B.; Williston, G.; Brown, L.; El-Shaarawi, A.; Vandenbyllaardt, L.; Honeyfeld, D.; Tillitt, D.; Wolgamood, M.; Brown, S.B.

    2007-01-01

    Alewives (Alosa pseudoharengus), the major prey fish for Lake Ontario, contain thiaminase. They are associated with development of a thiamine deficiency in salmonines which greatly increases the potential for developing an early mortality syndrome (EMS). To assess the possible effects of thiamine deficiency on salmonine reproduction we measured egg thiamine concentrations for five species of Lake Ontario salmonines. From this we estimated the proportion of families susceptible to EMS based on whether they were below the ED20, the egg thiamine concentration associated with 20% mortality due to EMS. The ED20s were 1.52, 2.63, and 2.99 nmol/g egg for Chinook salmon (Oncorhynchus tshawytscha), lake trout (Salvelinus namaycush), and coho salmon (Oncorhynchus kisutch), respectively. Based on the proportion of fish having egg thiamine concentrations falling below the ED20, the risk of developing EMS in Lake Ontario was highest for lake trout, followed by coho (O. kisutch), and Chinook salmon, with the least risk for rainbow trout (O. mykiss). For lake trout from western Lake Ontario, mean egg thiamine concentration showed significant annual variability during 1994 to 2003, when the proportion of lake trout at risk of developing EMS based on ED20 ranged between 77 and 100%. Variation in the annual mean egg thiamine concentration for western Lake Ontario lake trout was positively related (p < 0.001, r2 = 0.94) with indices of annual adult alewife biomass. While suggesting the possible involvement of density-dependent changes in alewives, the changes are small relative to egg thiamine concentrations when alewife are not part of the diet and are of insufficient magnitude to allow for natural reproduction by lake trout.

  1. Evaluation of offshore stocking of Lake Trout in Lake Ontario

    Science.gov (United States)

    Lantry, B.F.; O'Gorman, R.; Strang, T.G.; Lantry, J.R.; Connerton, M.J.; Schanger, T.

    2011-01-01

    Restoration stocking of hatchery-reared lake trout Salvelinus namaycush has occurred in Lake Ontario since 1973. In U.S. waters, fish stocked through 1990 survived well and built a large adult population. Survival of yearlings stocked from shore declined during 1990–1995, and adult numbers fell during 1998–2005. Offshore stocking of lake trout was initiated in the late 1990s in response to its successful mitigation of predation losses to double-crested cormorants Phalacrocorax auritus and the results of earlier studies that suggested it would enhance survival in some cases. The current study was designed to test the relative effectiveness of three stocking methods at a time when poststocking survival for lake trout was quite low and losses due to fish predators was a suspected factor. The stocking methods tested during 2000–2002 included May offshore, May onshore, and June onshore. Visual observations during nearshore stockings and hydroacoustic observations of offshore stockings indicated that release methods were not a direct cause of fish mortality. Experimental stockings were replicated for 3 years at one site in the southwest and for 2 years at one site in the southeast. Offshore releases used a landing craft to transport hatchery trucks from 3 to 6 km offshore out to 55–60-m-deep water. For the southwest site, offshore stocking significantly enhanced poststocking survival. Among the three methods, survival ratios were 1.74 : 1.00 : 1.02 (May offshore : May onshore : June onshore). Although not statistically significant owing to the small samples, the trends were similar for the southeast site, with survival ratios of 1.67 : 1.00 : 0.72. Consistent trends across years and sites indicated that offshore stocking of yearling lake trout during 2000–2002 provided nearly a twofold enhancement in survival; however, this increase does not appear to be great enough to achieve the 12-fold enhancement necessary to return population abundance to restoration

  2. Asotin Creek Instream Habitat Alteration Projects: 1998 Habitat Evaluation Surveys.

    Energy Technology Data Exchange (ETDEWEB)

    Bumgarner, Joseph D.

    1999-03-01

    The Asotin Creek Model Watershed Master Plan was completed 1994. The plan was developed by a landowner steering committee for the Asotin County Conservation District (ACCD), with technical support from the various Federal, State and local entities. Actions identified within the plan to improve the Asotin Creek ecosystem fall into four main categories, (1) Stream and Riparian, (2) Forestland, (3) Rangeland, and (4) Cropland. Specific actions to be carried out within the stream and in the riparian area to improve fish habitat were, (a) create more pools, (b) increase the amount of large organic debris (LOD), (c) increase the riparian buffer zone through tree planting, and (d) increase fencing to limit livestock access; additionally, the actions are intended to stabilize the river channel, reduce sediment input, and protect private property. Fish species of main concern in Asotin Creek are summer steelhead (Oncorhynchus mykiss), spring chinook (Oncorhynchus tshawytscha), and bull trout (Salvelinus confluentus). Spring chinook in Asotin Creek are considered extinct (Bumgarner et al. 1998); bull trout and summer steelhead are below historical levels and are currently as ''threatened'' under the ESA. In 1998, 16 instream habitat projects were planned by ACCD along with local landowners. The ACCD identified the need for a more detailed analysis of these instream projects to fully evaluate their effectiveness at improving fish habitat. The Washington Department of Fish and Wildlife's (WDFW) Snake River Lab (SRL) was contracted by the ACCD to take pre-construction measurements of the existing habitat (pools, LOD, width, depth, etc.) within each identified site, and to eventually evaluate fish use within these sites. All pre-construction habitat measurements were completed between 6 and 14 July, 1998. 1998 was the first year that this sort of evaluation has occurred. Post construction measurements of habitat structures installed in 1998, and fish

  3. Direct and indirect responses of a freshwater food web to a potent synthetic oestrogen

    Science.gov (United States)

    Kidd, Karen A.; Paterson, Michael J.; Rennie, Michael D.; Podemski, Cheryl L.; Findlay, Dave L.; Blanchfield, Paul J.; Liber, Karsten

    2014-01-01

    Endocrine-disrupting chemicals (EDCs) in municipal effluents directly affect the sexual development and reproductive success of fishes, but indirect effects on invertebrate prey or fish predators through reduced predation or prey availability, respectively, are unknown. At the Experimental Lakes Area in northwestern Ontario, Canada, a long-term, whole-lake experiment was conducted using a before-after-control-impact design to determine both direct and indirect effects of the synthetic oestrogen used in the birth control pill, 17α-ethynyloestradiol (EE2). Algal, microbial, zooplankton and benthic invertebrate communities showed no declines in abundance during three summers of EE2 additions (5–6 ng l−1), indicating no direct toxic effects. Recruitment of fathead minnow (Pimephales promelas) failed, leading to a near-extirpation of this species both 2 years during (young-of-year, YOY) and 2 years following (adults and YOY) EE2 additions. Body condition of male lake trout (Salvelinus namaycush) and male and female white sucker (Catostomus commersonii) declined before changes in prey abundance, suggesting direct effects of EE2 on this endpoint. Evidence of indirect effects of EE2 was also observed. Increases in zooplankton, Chaoborus, and emerging insects were observed after 2 or 3 years of EE2 additions, strongly suggesting indirect effects mediated through the reduced abundance of several small-bodied fishes. Biomass of top predator lake trout declined by 23–42% during and after EE2 additions, most probably an indirect effect from the loss of its prey species, the fathead minnow and slimy sculpin (Cottus cognatus). Our results demonstrate that small-scale studies focusing solely on direct effects are likely to underestimate the true environmental impacts of oestrogens in municipal wastewaters and provide further evidence of the value of whole-ecosystem experiments for understanding indirect effects of EDCs and other aquatic stressors. PMID:25405967

  4. Malheur River Basin cooperative bull trout/redband trout research project, annual report FY 1999; ANNUAL

    International Nuclear Information System (INIS)

    The purpose of this study is to document the seasonal distribution of adult/sub-adult bull trout (Salvelinus confluentus) in the Malheur River basin. Due to the decline of bull trout in the Columbia Basin, the United States Fish and Wildlife Service listed bull trout as a threatened species in June 1998. Past land management activities; construction of dams; and fish eradication projects in the North Fork and Middle Fork Malheur River by poisoning have worked in concert to cumulatively impact native species in the Malheur Basin (Bowers et. al. 1993). Survival of the remaining bull trout populations is severely threatened (Buchanan 1997). 1999 Research Objects are: (1) Document the migratory patterns of adult/sub-adult bull trout in the North Fork Malheur River; (2) Determine the seasonal bull trout use of Beulah Reservoir and bull trout entrainment; and (3) Timing and location of bull trout spawning in the North Fork Malheur River basin. The study area includes the Malheur basin from the mouth of the Malheur River located near Ontario, Oregon to the headwaters of the North Fork Malheur River (Map 1). All fish collected and most of the telemetry effort was done on the North Fork Malheur River subbasin (Map 2). Fish collection was conducted on the North Fork Malheur River at the tailwaters of Beulah Reservoir (RK 29), Beulah Reservoir (RK 29-RK 33), and in the North Fork Malheur River at Crane Crossing (RK 69) to the headwaters of the North Fork Malheur. Radio telemetry was done from the mouth of the Malheur River in Ontario, Oregon to the headwaters of the North Fork Malheur. This report will reflect all migration data collected from 3/1/99 to 12/31/99

  5. Laboratory evaluation of a lake trout bioenergetics model

    Science.gov (United States)

    Madenjian, Charles P.; O'Connor, Daniel V.

    1999-01-01

    Lake trout Salvelinus namaycush, aged 3 and 6 years and with average weights of 700 and 2,000 g, were grown in laboratory tanks for up to 407 d under a thermal regime similar to that experienced by lake trout in nearshore Lake Michigan. Lake trout were fed alewifeAlosa pseudoharengus and rainbow smelt Osmerus mordax, prey typical of lake trout in Lake Michigan. Of the 120 lake trout used in the experiment, 40 were fed a low ration (0.25% of their body weight per day), 40 were fed a medium ration (0.5% of their body weight per day), and 40 were fed a high ration (ad libitum). We measured consumption and growth, and we compared observed consumption with that predicted by the Wisconsin bioenergetics model. For lake trout fed the medium ration, model predictions for monthly consumption were unbiased. Moreover, predicted cumulative consumption by medium-ration lake trout for the entire experiment (320 d for smaller lake trout and 407 d for larger lake trout) agreed quite well with observed cumulative consumption; predictions were as close as within 0.1 to 5.2% of observed cumulative consumption. Even so, the model consistently overestimated consumption by low-ration fish and underestimated consumption by high-ration fish. The bias was significant in both cases, but was more severe for the low-ration trout. Because the low-ration and high-ration regimes were probably unrealistic for lake trout residing in Lake Michigan and because the model fit our laboratory data rather well for medium-ration trout, we conclude that applying the Wisconsin bioenergetics model to the Lake Michigan lake trout population in order to estimate the amount of prey fish consumed by lake trout each year is appropriate.

  6. Coupling age-structured stock assessment and fish bioenergetics models: a system of time-varying models for quantifying piscivory patterns during the rapid trophic shift in the main basin of Lake Huron

    Science.gov (United States)

    He, Ji X.; Bence, James R.; Madenjian, Charles P.; Pothoven, Steven A.; Dobiesz, Norine E.; Fielder, David G.; Johnson, James E.; Ebener, Mark P.; Cottrill, Adam R.; Mohr, Lloyd C.; Koproski, Scott R.

    2015-01-01

    We quantified piscivory patterns in the main basin of Lake Huron during 1984–2010 and found that the biomass transfer from prey fish to piscivores remained consistently high despite the rapid major trophic shift in the food webs. We coupled age-structured stock assessment models and fish bioenergetics models for lake trout (Salvelinus namaycush), Chinook salmon (Oncorhynchus tshawytscha), walleye (Sander vitreus), and lake whitefish (Coregonus clupeaformis). The model system also included time-varying parameters or variables of growth, length–mass relations, maturity schedules, energy density, and diets. These time-varying models reflected the dynamic connections that a fish cohort responded to year-to-year ecosystem changes at different ages and body sizes. We found that the ratio of annual predation by lake trout, Chinook salmon, and walleye combined with the biomass indices of age-1 and older alewives (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax) increased more than tenfold during 1987–2010, and such increases in predation pressure were structured by relatively stable biomass of the three piscivores and stepwise declines in the biomass of alewives and rainbow smelt. The piscivore stability was supported by the use of alternative energy pathways and changes in relative composition of the three piscivores. In addition, lake whitefish became a new piscivore by feeding on round goby (Neogobius melanostomus). Their total fish consumption rivaled that of the other piscivores combined, although fish were still a modest proportion of their diet. Overall, the use of alternative energy pathways by piscivores allowed the increases in predation pressure on dominant diet species.

  7. Development and evaluation of a bioenergetics model for bull trout

    Science.gov (United States)

    Mesa, Matthew G.; Welland, Lisa K.; Christiansen, Helena E.; Sauter, Sally T.; Beauchamp, David A.

    2013-01-01

    We conducted laboratory experiments to parameterize a bioenergetics model for wild Bull Trout Salvelinus confluentus, estimating the effects of body mass (12–1,117 g) and temperature (3–20°C) on maximum consumption (C max) and standard metabolic rates. The temperature associated with the highest C max was 16°C, and C max showed the characteristic dome-shaped temperature-dependent response. Mass-dependent values of C max (N = 28) at 16°C ranged from 0.03 to 0.13 g·g−1·d−1. The standard metabolic rates of fish (N = 110) ranged from 0.0005 to 0.003 g·O2·g−1·d−1 and increased with increasing temperature but declined with increasing body mass. In two separate evaluation experiments, which were conducted at only one ration level (40% of estimated C max), the model predicted final weights that were, on average, within 1.2 ± 2.5% (mean ± SD) of observed values for fish ranging from 119 to 573 g and within 3.5 ± 4.9% of values for 31–65 g fish. Model-predicted consumption was within 5.5 ± 10.9% of observed values for larger fish and within 12.4 ± 16.0% for smaller fish. Our model should be useful to those dealing with issues currently faced by Bull Trout, such as climate change or alterations in prey availability.

  8. Using bioenergetics modeling to estimate consumption of native juvenile salmonids by nonnative northern pike in the Upper Flathead River System, Montana

    Science.gov (United States)

    Muhlfeld, C.C.; Bennett, D.H.; Kirk, Steinhorst R.; Marotz, B.; Boyer, M.

    2008-01-01

    Introductions of nonnative northern pike Esox lucius have created recreational fisheries in many waters in the United States and Canada, yet many studies have shown that introduced northern pike may alter the composition and structure of fish communities through predation. We estimated the abundance of nonnative northern pike (2002-2003) and applied food habits data (1999-2003) to estimate their annual consumption of native bull trout Salvelinus confluentus and westslope cutthroat trout Oncorhynchus clarkii lewisi juveniles in the upper Flathead River system, Montana. Population estimates were generally consistent among years and ranged from 1,200 to 1,300 individuals. Westslope cutthroat trout were present in the diet of younger (???600 mm) and older (>600 mm) northern pike during all seasons and bull trout were found only in larger northern pike during all seasons but summer. Bioenergetics modeling estimated that the northern pike population annually consumed a total of 8.0 metric tons (mt) of fish flesh; the highest biomass was composed of cyprinids (4.95 mt) followed by whitefishes Prosopium spp. (1.02 mt), bull trout (0.80 mt), westslope cutthroat trout (0.68 mt), yellow perch Perca flavescens (0.41 mt),1 and other fishes (centrarchids and cottids; 0.14 mt). Numerically, the northern pike population consumed more than 342,000 fish; cyprinids and catostomids comprised approximately 82% of prey fish (278,925), whereas over 13,000 westslope cutthroat trout and nearly 3,500 bull trout were eaten, comprising about 5% of the prey consumed. Our results suggest that predation by introduced northern pike is contributing to the lower abundance of native salmonids in the system and that a possible benefit might accrue to native salmonids by reducing these predatory interactions. ?? Copyright by the American Fisheries Society 2008.

  9. Tissue Phthalate Levels Correlate With Changes in Immune Gene Expression in a Population of Juvenile Wild Salmon.

    Science.gov (United States)

    Martins, Kelly; Hagedorn, Birgit; Ali, Shareen; Kennish, John; Applegate, Ben; Leu, Matthias; Epp, Lidia; Pallister, Chris; Zwollo, Patty

    2016-07-01

    Phthalates have detrimental effects on health and have been shown to dysregulate the immune system of mammals, birds, and fish. We recently reported that di(2-ethylhexyl) phthalate exposure reduces the abundance and inhibits the proliferation of rainbow trout (Oncorhynchus mykiss) IgM(+) B lymphocytes and expression of secreted immunoglobulin heavy-chain mu transcripts in an in vitro culture system. We proposed that phthalates act as immunomodulators by modifying the normal B cell-activation pathways by accelerating B cell differentiation while suppressing plasmablast expansion, thus resulting in fewer IgM-secreting plasma cells. This hypothesis was tested here in an in vivo field study of juvenile Dolly Varden (Salvelinus malma) from a plastic-polluted lake in the Gulf of Alaska. Fish tissues were analyzed for both phthalate levels using liquid chromatography-coupled tandem mass spectrometry and for changes in immune gene expression using reverse transcriptase-real time polymerase chain reaction. Results showed that fish with higher tissue levels of di(2-ethylhexyl) phthalate, di(n-butyl) phthalate, and/or dimethyl phthalate expressed significantly fewer secreted and membrane-bound immunoglobulin heavy-chain mu and Blimp1 transcripts in their hematopoietic tissue. This suggests that in vivo uptake of phthalates in fish changes the expression of B cell-specific genes. Chronic exposure to phthalates likely dysregulates normal B-lymphoid development and antibody responses in salmonids and may increase susceptibility to infection. Given the conserved nature of B-lineage cells in vertebrate animals, other marine species may be similarly affected by chronic phthalate exposure. PMID:27177745

  10. Trophic transfer of persistent organochlorine contaminants (OCs) within an Arctic marine food web from the southern Beaufort-Chukchi Seas

    Energy Technology Data Exchange (ETDEWEB)

    Hoekstra, P.F.; O' Hara, T.M.; Fisk, A.T.; Borgaa, K.; Solomon, K.R.; Muir, D.C.G

    2003-08-01

    The trophic status and biomagnification of persistent OCs within the near-shore Beaufort-Chukchi Seas food web from Barrow, AK is discussed. - Stable isotope values ({delta}{sup 13}C, {delta}{sup 15}N) and concentrations of persistent organochlorine contaminants (OCs) were determined to evaluate the near-shore marine trophic status of biota and biomagnification of OCs from the southern Beaufort-Chukchi Seas (1999-2000) near Barrow, AK. The biota examined included zooplankton (Calanus spp.), fish species such as arctic cod (Boreogadus saida), arctic char (Salvelinus alpinus), pink salmon (Oncorhynchus gorbuscha), and fourhorn sculpin (Myoxocephalus quadricornis), along with marine mammals, including bowhead whales (Balaena mysticetus), beluga whales (Delphinapterus leucas), ringed seals (Phoca hispida) and bearded seals (Erignathus barbatus). The isotopically derived trophic position of biota from the Beaufort-Chukchi Seas marine food web, avian fauna excluded, is similar to other coastal food webs in the Arctic. Concentrations of OCs in marine mammals were significantly greater than in fish and corresponded with determined trophic level. In general, OCs with the greatest food web magnification factors (FWMFs) were those either formed due to biotransformation (e.g. p,p'-DDE, oxychlordane) or considered recalcitrant (e.g. {beta}-HCH, 2,4,5-Cl substituted PCBs) in most biota, whereas concentrations of OCs that are considered to be readily eliminated (e.g. {gamma}-HCH) did not correlate with trophic level. Differences in physical-chemical properties of OCs, feeding strategy and possible biotransformation were reflected in the variable biomagnification between fish and marine mammals. The FWMFs in the Beaufort-Chukchi Seas region were consistent with reported values in the Canadian Arctic and temperate food webs, but were statistically different than FWMFs from the Barents and White Seas, indicating that the spatial variability of OC contamination in top

  11. Climate, invasive species and land use drive population dynamics of a cold-water specialist

    Science.gov (United States)

    Kovach, Ryan P.; Al-Chokhachy, Robert K.; Whited, Diane C.; Schmetterling, David A.; Dux, Andrew M; Muhlfeld, Clint C.

    2016-01-01

    Climate change is an additional stressor in a complex suite of threats facing freshwater biodiversity, particularly for cold-water fishes. Research addressing the consequences of climate change on cold-water fish has generally focused on temperature limits defining spatial distributions, largely ignoring how climatic variation influences population dynamics in the context of other existing stressors.We used long-term data from 92 populations of bull trout Salvelinus confluentus – one of North America's most cold-adapted fishes – to quantify additive and interactive effects of climate, invasive species and land use on population dynamics (abundance, variability and growth rate).Populations were generally depressed, more variable and declining where spawning and rearing stream habitat was limited, invasive species and land use were prevalent and stream temperatures were highest. Increasing stream temperature acted additively and independently, whereas land use and invasive species had additive and interactive effects (i.e. the impact of one stressor depended on exposure to the other stressor).Most (58%–78%) of the explained variation in population dynamics was attributed to the presence of invasive species, differences in life history and management actions in foraging habitats in rivers, lakes and reservoirs. Although invasive fishes had strong negative effects on populations in foraging habitats, proactive control programmes appeared to effectively temper their negative impact.Synthesis and applications. Long-term demographic data emphasize that climate warming will exacerbate imperilment of cold-water specialists like bull trout, yet other stressors – especially invasive fishes – are immediate threats that can be addressed by proactive management actions. Therefore, climate-adaptation strategies for freshwater biodiversity should consider existing abiotic and biotic stressors, some of which provide potential and realized opportunity for conservation

  12. A framework for assessing the feasibility of native fish conservation translocations: Applications to threatened Bull Trout

    Science.gov (United States)

    Galloway, Benjamin T.; Muhlfeld, Clint C.; Guy, Christopher S.; Downs, Christopher C.; Fredenberg, Wade A.

    2016-01-01

    There is an urgent need to consider more aggressive and direct interventions for the conservation of freshwater fishes that are threatened by invasive species, habitat loss, and climate change. Conservation introduction (moving a species outside its indigenous range to other areas where conditions are predicted to be more suitable) is one type of translocation strategy that fisheries managers can use to establish new conservation populations in areas of refugia. To date, however, there are few examples of successful conservation-based introductions. Many attempts fail to establish new populations-in part because environmental factors that might influence success are inadequately evaluated before the translocation is implemented. We developed a framework to assess the feasibility of rescuing threatened fish populations through translocation into historically unoccupied stream and lake habitats. The suitability of potential introduction sites was evaluated based on four major components: the recipient habitat, recipient community, donor population, and future threats. Specific questions were then developed to evaluate each major component. The final assessment was based on a scoring system that addressed each question by using criteria developed from characteristics representative of highly suitable habitats and populations. This framework was used to evaluate the proposed within-drainage translocation of three Bull Trout Salvelinus confluentus populations in Glacier National Park, Montana. Our results indicated that within-drainage translocation is a feasible strategy for conserving locally adapted populations of Bull Trout through the creation of new areas of refugia in Glacier National Park. The framework provides a flexible platform that can help managers make informed decisions for moving threatened fishes into new areas of refugia for conservation and recovery programs.

  13. Developing recreational harvest regulations for an unexploited lake trout population

    Science.gov (United States)

    Lenker, Melissa A; Weidel, Brian C.; Jensen, Olaf P.; Solomon, Christopher T.

    2016-01-01

    Developing fishing regulations for previously unexploited populations presents numerous challenges, many of which stem from a scarcity of baseline information about abundance, population productivity, and expected angling pressure. We used simulation models to test the effect of six management strategies (catch and release; trophy, minimum, and maximum length limits; and protected and exploited slot length limits) on an unexploited population of Lake Trout Salvelinus namaycush in Follensby Pond, a 393-ha lake located in New York State’s Adirondack Park. We combined field and literature data and mark–recapture abundance estimates to parameterize an age-structured population model and used the model to assess the effects of each management strategy on abundance, catch per unit effort (CPUE), and harvest over a range of angler effort (0–2,000 angler-days/year). Lake Trout density (3.5 fish/ha for fish ≥ age 13, the estimated age at maturity) was similar to densities observed in other unexploited systems, but growth rate was relatively slow. Maximum harvest occurred at levels of effort ≤ 1,000 angler-days/year in all the scenarios considered. Regulations that permitted harvest of large postmaturation fish, such as New York’s standard Lake Trout minimum size limit or a trophy size limit, resulted in low harvest and high angler CPUE. Regulations that permitted harvest of small and sometimes immature fish, such as a protected slot or maximum size limit, allowed high harvest but resulted in low angler CPUE and produced rapid declines in harvest with increases in effort beyond the effort consistent with maximum yield. Management agencies can use these results to match regulations to management goals and to assess the risks of different management options for unexploited Lake Trout populations and other fish species with similar life history traits.

  14. Vateritic sagitta in wild and stocked lake trout: Applicability to stock origin

    Science.gov (United States)

    Bowen, Charles A., II; Bronte, Charles R.; Argyle, Ray L.; Adams, Jean V.; Johnson, James E.

    1999-01-01

    Aragonite is the normal form of calcium carbonate found in teleost otoliths, but it is sometimes replaced by vaterite, an alternate crystalline structure. We investigated the assumption that sagittal otoliths with vaterite replacement were unique to stocked lake trout Salvelinus namaycush in the Laurentian Great Lakes. Earlier studies had attributed these abnormalities to stocking stress, and proposed that the presence of vaterite could separate individual unmarked stocked lake trout from their wild counterparts. We examined and described the frequency of vateritic sagittae in two wild and three stocked populations of lake trout from the Great Lakes and a wild population from a remote inland lake in northern Canada. Among lake trout caught 2–12 years after being stocked, prevalence of vateritic sagittae was 66% for Lake Superior fish, 75% for Lake Huron fish, and 86% for Lake Ontario fish. Among wild fish caught, vateritic sagittae were present in 37% of Lake Superior fish, 22% of Lake Huron fish, and 49% of northern Canada fish. We also compared year-to-year differences in prevalence in four year-classes of fingerling lake trout reared in two U.S. national lake trout hatcheries. Prior to release, between 53 and 84% of the hatchery fish had at least one vateritic sagitta, and prevalence increased with handling associated with hatchery practices. Vateritic sagittae in wild fish might also indicate stress in nature. The presence of vateritic sagittae in both wild and stocked fish compromises the use of this characteristic as an unequivocal indicator of a particular fish's origin. Among-population differences in both the prevalence and the extent of vaterite replacement, however, may provide a means of differentiating between stocks of sympatric unmarked wild and stocked lake trout.

  15. Bathythermal habitat use by strains of Great Lakes- and Finger Lakes-origin lake trout in Lake Huron after a change in prey fish abundance and composition

    Science.gov (United States)

    Bergstedt, Roger A.; Argyle, Ray L.; Krueger, Charles C.; Taylor, William W.

    2012-01-01

    A study conducted in Lake Huron during October 1998–June 2001 found that strains of Great Lakes-origin (GLO) lake trout Salvelinus namaycush occupied significantly higher temperatures than did Finger Lakes-origin (FLO; New York) lake trout based on data from archival (or data storage) telemetry tags that recorded only temperature. During 2002 and 2003, we implanted archival tags that recorded depth as well as temperature in GLO and FLO lake trout in Lake Huron. Data subsequently recorded by those tags spanned 2002–2005. Based on those data, we examined whether temperatures and depths occupied by GLO and FLO lake trout differed during 2002–2005. Temperatures occupied during those years were also compared with occupied temperatures reported for 1998–2001, before a substantial decline in prey fish biomass. Temperatures occupied by GLO lake trout were again significantly higher than those occupied by FLO lake trout. This result supports the conclusion of the previous study. The GLO lake trout also occupied significantly shallower depths than FLO lake trout. In 2002–2005, both GLO and FLO lake trout occupied significantly lower temperatures than they did in 1998–2001. Aside from the sharp decline in prey fish biomass between study periods, the formerly abundant pelagic alewife Alosa pseudoharengus virtually disappeared and the demersal round goby Neogobius melanostomus invaded the lake and became locally abundant. The lower temperatures occupied by lake trout in Lake Huron during 2002–2005 may be attributable to changes in the composition of the prey fish community, food scarcity (i.e., a retreat to cooler water could increase conversion efficiency), or both.

  16. Seasonally dynamic diel vertical migrations of Mysis diluviana, coregonine fishes, and siscowet lake trout in the pelagia of western Lake Superior

    Science.gov (United States)

    Ahrenstorff, Tyler D.; Hrabik, Thomas R.; Stockwell, Jason D.; Yule, Daniel L.; Sass, Greg G.

    2011-01-01

    Diel vertical migrations are common among many aquatic species and are often associated with changing light levels. The underlying mechanisms are generally attributed to optimizing foraging efficiency or growth rates and avoiding predation risk (μ). The objectives of this study were to (1) assess seasonal and interannual changes in vertical migration patterns of three trophic levels in the Lake Superior pelagic food web and (2) examine the mechanisms underlying the observed variability by using models of foraging, growth, and μ. Our results suggest that the opossum shrimp Mysis diluviana, kiyi Coregonus kiyi, and siscowet lake trout Salvelinus namaycush migrate concurrently during each season, but spring migrations are less extensive than summer and fall migrations. In comparison with M. diluviana, kiyis, and siscowets, the migrations by ciscoes C. artedi were not as deep in the water column during the day, regardless of season. Foraging potential and μ probably drive the movement patterns of M. diluviana, while our modeling results indicate that movements by kiyis and ciscoes are related to foraging opportunity and growth potential and receive a lesser influence from μ. The siscowet is an abundant apex predator in the pelagia of Lake Superior and probably undertakes vertical migrations in the water column to optimize foraging efficiency and growth. The concurrent vertical movement patterns of most species are likely to facilitate nutrient transport in this exceedingly oligotrophic ecosystem, and they demonstrate strong linkages between predators and prey. Fishery management strategies should use an ecosystem approach and should consider how altering the densities of long-lived top predators produces cascading effects on the nutrient cycling and energy flow in lower trophic levels.

  17. Comparative bioenergetics modeling of two Lake Trout morphotypes

    Science.gov (United States)

    Kepler, Megan V.; Wagner, Tyler; Sweka, John A.

    2014-01-01

    Efforts to restore Lake Trout Salvelinus namaycush in the Laurentian Great Lakes have been hampered for decades by several factors, including overfishing and invasive species (e.g., parasitism by Sea Lampreys Petromyzon marinus and reproductive deficiencies associated with consumption of Alewives Alosa pseudoharengus). Restoration efforts are complicated by the presence of multiple body forms (i.e., morphotypes) of Lake Trout that differ in habitat utilization, prey consumption, lipid storage, and spawning preferences. Bioenergetics models constitute one tool that is used to help inform management and restoration decisions; however, bioenergetic differences among morphotypes have not been evaluated. The goal of this research was to investigate bioenergetic differences between two actively stocked morphotypes: lean and humper Lake Trout. We measured consumption and respiration rates across a wide range of temperatures (4–22°C) and size-classes (5–100 g) to develop bioenergetics models for juvenile Lake Trout. Bayesian estimation was used so that uncertainty could be propagated through final growth predictions. Differences between morphotypes were minimal, but when present, the differences were temperature and weight dependent. Basal respiration did not differ between morphotypes at any temperature or size-class. When growth and consumption differed between morphotypes, the differences were not consistent across the size ranges tested. Management scenarios utilizing the temperatures presently found in the Great Lakes (e.g., predicted growth at an average temperature of 11.7°C and 14.4°C during a 30-d period) demonstrated no difference in growth between the two morphotypes. Due to a lack of consistent differences between lean and humper Lake Trout, we developed a model that combined data from both morphotypes. The combined model yielded results similar to those of the morphotype-specific models, suggesting that accounting for morphotype differences may

  18. Population connectivity: dam migration mitigations and contemporary site fidelity in arctic char

    Directory of Open Access Journals (Sweden)

    Heggenes Jan

    2011-07-01

    Full Text Available Abstract Background Animal feeding and spawning migrations may be limited by physical barriers and behavioral interactions. Dam constructions (e.g. hydropower commonly include gateways for fish migrations to sustain ecological connectivity. Relative genetic impacts of fish passage devices versus natural processes (e.g. hybrid inferiority are, however, rarely studied. We examined genetic (i.e. microsatellite population connectivity of highly migrating lake-dwelling Arctic char (Salvelinus alpinus, introduced 20 generations ago, across and within two subalpine lakes separated by a dam with a subterranean tunnel and spill gates after 7 generations. Due to water flow regime, the time window for fish migration is highly restricted. Results Char populations, with similar genetic structuring and diversity observed across and within lakes, were admixed across the dam with fishways during feeding. For spawning, however, statistically significant, but very low population differentiation (θ; 0.002 - 0.013 was found in nine out of ten reproductive site comparisons, reflecting interactions between extensive migration (mean first generation (F0 = 10.8% and initial site fidelity. Simulations indicated that genetic drift among relatively small effective populations (mean Ne = 62 may have caused the observed contemporary differentiation. Novel Bayesian analyses indicated mean contributions of 71% F0 population hybrids in spawning populations, of which 76% had maternal or paternal native origin. Conclusions Ecological connectivity between lakes separated by a dam has been retained through construction of fishways for feeding migration. Considerable survival and homing to ancestral spawning sites in hybrid progeny was documented. Population differentiation despite preceding admixture is likely caused by contemporary reduced reproductive fitness of population hybrids. The study documents the beginning stages of population divergence among spatial aggregations with

  19. Lipid and moisture content modeling of amphidromous Dolly Varden using bioelectrical impedance analysis

    Science.gov (United States)

    Stolarski, J.T.; Margraf, F.J.; Carlson, J.G.; Sutton, T.M.

    2014-01-01

    The physiological well-being or condition of fish is most commonly estimated from aspects of individual morphology. However, these metrics may be only weakly correlated with nutritional reserves stored as lipid, the primary form of accumulated energy in fish. We constructed and evaluated bioelectrical impedance analysis (BIA) models as an alternative method of assessing condition in amphidromous Dolly Varden Salvelinus malma collected from nearshore estuarine and lotic habitats of the Alaskan Arctic. Data on electrical resistance and reactance were collected from the lateral and ventral surfaces of 192 fish, and whole-body percent lipid and moisture content were determined using standard laboratory methods. Significant inverse relationships between temperature and resistance and reactance prompted the standardization of these data to a constant temperature using corrective equations developed herein. No significant differences in resistance or reactance were detected among spawning and nonspawning females after accounting for covariates, suggesting that electrical pathways do not intersect the gonads. Best-fit BIA models incorporating electrical variables calculated from the lateral and ventral surfaces produced the strongest associations between observed and model-predicted estimates of proximate content. These models explained between 6% and 20% more of the variability in laboratory-derived estimates of proximate content than models developed from single-surface BIA data and 32% more than models containing only length and weight data. While additional research is required to address the potential effects of methodological variation, bioelectrical impedance analysis shows promise as a way to provide high-quality, minimally invasive estimates of Dolly Varden lipid or moisture content in the field with only small increases in handling time.

  20. Fasting augments PCB impact on liver metabolism in anadromous arctic char

    Science.gov (United States)

    Vijayan, M.M.; Aluru, N.; Maule, A.G.; Jorgensen, E.H.

    2006-01-01

    Anadromous arctic char (Salvelinus alpinus) undertake short feeding migrations to seawater every summer and accumulate lipids, while the rest of the year is spent in fresh water where the accumulated lipid reserves are mobilized. We tested the hypothesis that winter fasting and the associated polychlorinated biphenyls' (PCBs) redistribution from lipid depots to critical tissues impair the liver metabolic capacity in these animals. Char were administered Aroclor 1254 (0, 1, 10, and 100 mg/ kg body mass) orally and maintained for 4 months without feeding to mimic seasonal winter fasting, while fed groups (0 and 100 mg Aroclor 1254/kg) were maintained for comparison. A clear dose-related increase in PCB accumulation and cytochrome P4501A (CYP1A) protein content was observed in the livers of fasted fish. This PCB concentration and CYP1A response with the high dose of Aroclor were 1.5-fold and 3-fold greater in the fasted than in the fed fish, respectively. In fed fish, PCB exposure lowered liver glycogen content, whereas none of the other metabolic indicators were significantly affected. In fasted fish, PCB exposure depressed liver glycogen content and activities of glucose-6-phosphate dehydrogenase, alanine aminotransferase, lactate dehydrogenase, and phosphoenolpyruvate carboxykinase and elevated 3-hydroxyacylcoA dehydrogenase activity and glucocorticoid receptor protein expression. There were no significant impacts of PCB on heat shock protein 70 (hsp70) and hsp90 contents in either fed or fasted fish. Collectively, our study demonstrates that winter emaciation associated with the anadromous lifestyle predisposes arctic char to PCB impact on hepatic metabolism including disruption of the adaptive metabolic responses to extended fasting. ?? 2006 Oxford University Press.

  1. Persistent organic pollutants in biota samples collected during the Ymer-80 expedition to the Arctic

    Directory of Open Access Journals (Sweden)

    Henrik Kylin

    2015-10-01

    Full Text Available During the 1980 expedition to the Arctic with the icebreaker Ymer, a number of vertebrate species were sampled for determination of persistent organic pollutants. Samples of Arctic char (Salvelinus alpinus, n=34, glaucous gull (Larus hyperboreus, n=8, common eider (Somateria mollissima, n=10, Brünnich's guillemot (Uria lomvia, n=9, ringed seal (Pusa hispida, n=2 and polar bear (Ursus maritimus, n=2 were collected. With the exception of Brünnich's guillemot, there was a marked contamination difference of birds from western as compared to eastern/northern Svalbard. Samples in the west contained a larger number of polychlorinated biphenyl (PCB congeners and also polychlorinated terphenyls, indicating local sources. Brünnich's guillemots had similar pollutant concentrations in the west and east/north; possibly younger birds were sampled in the west. In Arctic char, pollutant profiles from lake Linnévatn (n=5, the lake closest to the main economic activities in Svalbard, were similar to profiles in Arctic char from the Shetland Islands (n=5, but differed from lakes to the north and east in Svalbard (n=30. Arctic char samples had higher concentrations of hexachlorocyclohexanes (HCHs than the marine species of birds and mammals, possibly due to accumulation via snowmelt. Compared to the Baltic Sea, comparable species collected in Svalbard had lower concentrations of PCB and dichlorodiphenyltrichloroethane (DDT, but similar concentrations indicating long-range transport of hexachlorobenzene, HCHs and cyclodiene pesticides. In samples collected in Svalbard in 1971, the concentrations of PCB and DDT in Brünnich's guillemot (n=7, glaucous gull (n=2 and polar bear (n=2 were similar to the concentrations found in 1980.

  2. Identification of Cryptosporidium Species in Fish from Lake Geneva (Lac Léman) in France.

    Science.gov (United States)

    Certad, Gabriela; Dupouy-Camet, Jean; Gantois, Nausicaa; Hammouma-Ghelboun, Ourida; Pottier, Muriel; Guyot, Karine; Benamrouz, Sadia; Osman, Marwan; Delaire, Baptiste; Creusy, Colette; Viscogliosi, Eric; Dei-Cas, Eduardo; Aliouat-Denis, Cecile Marie; Follet, Jérôme

    2015-01-01

    Cryptosporidium, a protozoan parasite that can cause severe diarrhea in a wide range of vertebrates including humans, is increasingly recognized as a parasite of a diverse range of wildlife species. However, little data are available regarding the identification of Cryptosporidium species and genotypes in wild aquatic environments, and more particularly in edible freshwater fish. To evaluate the prevalence of Cryptosporidiumspp. in fish from Lake Geneva (Lac Léman) in France, 41 entire fish and 100 fillets (cuts of fish flesh) were collected from fishery suppliers around the lake. Nested PCR using degenerate primers followed by sequence analysis was used. Five fish species were identified as potential hosts of Cryptosporidium: Salvelinus alpinus, Esox lucius, Coregonus lavaretus, Perca fluviatilis, and Rutilus rutilus. The presence of Cryptosporidium spp. was found in 15 out of 41 fish (37%), distributed as follows: 13 (87%) C. parvum, 1 (7%) C. molnari, and 1 (7%) mixed infection (C. parvum and C. molnari). C. molnari was identified in the stomach, while C. parvum was found in the stomach and intestine. C. molnari was also detected in 1 out of 100 analyzed fillets. In order to identify Cryptosporidium subtypes, sequencing of the highly polymorphic 60-kDa glycoprotein (gp60) was performed. Among the C. parvum positive samples, three gp60 subtypes were identified: IIaA15G2R1, IIaA16G2R1, and IIaA17G2R1. Histological examination confirmed the presence of potential developmental stages of C. parvum within digestive epithelial cells. These observations suggest that C. parvum is infecting fish, rather than being passively carried. Since C. parvum is a zoonotic species, fish potentially contaminated by the same subtypes found in terrestrial mammals would be an additional source of infection for humans and animals, and may also contribute to the contamination of the environment with this parasite. Moreover, the risk of human transmission is strengthened by the

  3. Identification of Cryptosporidium Species in Fish from Lake Geneva (Lac Leman in France.

    Directory of Open Access Journals (Sweden)

    Gabriela Certad

    Full Text Available Cryptosporidium, a protozoan parasite that can cause severe diarrhea in a wide range of vertebrates including humans, is increasingly recognized as a parasite of a diverse range of wildlife species. However, little data are available regarding the identification of Cryptosporidium species and genotypes in wild aquatic environments, and more particularly in edible freshwater fish. To evaluate the prevalence of Cryptosporidiumspp. in fish from Lake Geneva (Lac Léman in France, 41 entire fish and 100 fillets (cuts of fish flesh were collected from fishery suppliers around the lake. Nested PCR using degenerate primers followed by sequence analysis was used. Five fish species were identified as potential hosts of Cryptosporidium: Salvelinus alpinus, Esox lucius, Coregonus lavaretus, Perca fluviatilis, and Rutilus rutilus. The presence of Cryptosporidium spp. was found in 15 out of 41 fish (37%, distributed as follows: 13 (87% C. parvum, 1 (7% C. molnari, and 1 (7% mixed infection (C. parvum and C. molnari. C. molnari was identified in the stomach, while C. parvum was found in the stomach and intestine. C. molnari was also detected in 1 out of 100 analyzed fillets. In order to identify Cryptosporidium subtypes, sequencing of the highly polymorphic 60-kDa glycoprotein (gp60 was performed. Among the C. parvum positive samples, three gp60 subtypes were identified: IIaA15G2R1, IIaA16G2R1, and IIaA17G2R1. Histological examination confirmed the presence of potential developmental stages of C. parvum within digestive epithelial cells. These observations suggest that C. parvum is infecting fish, rather than being passively carried. Since C. parvum is a zoonotic species, fish potentially contaminated by the same subtypes found in terrestrial mammals would be an additional source of infection for humans and animals, and may also contribute to the contamination of the environment with this parasite. Moreover, the risk of human transmission is strengthened by

  4. Umatilla Basin natural production monitoring and evaluation. Annual progress report, 1994--1995

    International Nuclear Information System (INIS)

    This report summarizes the activities of the Umatilla Basin Natural Production Monitoring and Evaluation Project (UBNPME) from September 30, 1994 to September 29, 1995. This program was funded by Bonneville Power Administration and was managed under the Fisheries Program, Department of Natural Resources, Confederated Tribes of the Umatilla Indian Reservation. An estimated 36.7 km (22.6 miles) of stream habitat were inventoried on the Umatilla River, Moonshine, Mission, Cottonwood and Coonskin Creeks. A total of 384 of 3,652 (10.5%) habitat units were electrofished. The number of juvenile fish captured follows: 2,953 natural summer steelhead (including resident rainbow trout; Oncorhynchus mykiss), one hatchery steelhead, 341 natural chinook salmon (O. tshawytscha), 163 natural coho salmon (O. kisutch), five bull trout (Salvelinus confluentus), 185 mountain whitefish (Prosopium williamsoni), and six northern squawfish (Ptychoicheilus oregonensis). The expanded population estimate for the areas surveyed was 73,716 salmonids with a mean density of 0.38 fish/m2. Relative salmonid abundance, seasonal distribution and habitat utilization were monitored at index sites throughout the basin. During index site monitoring, the following species were collected in addition to those listed above: american shad (Alosa sapidissima), smallmouth bass (Micropterus dolomieu), carp (Cyprinus carpio) and chiselmouth (Acrocheilus alutaceus). Thirty-nine sites were electrofished during the spring and summer seasons, while 36 sites were sampled in the fall season. A study of the migration movements and homing requirements of adult salmonids in the Umatilla River was conducted during the 1994-95 return years. Radio telemetry was used to evaluate the movements of adult salmonids past diversion dams in the lower Umatilla River and to determine migrational movements of salmonids following upstream transport

  5. A framework for assessing the feasibility of native fish conservation translocations: Applications to threatened bull trout

    Science.gov (United States)

    Galloway, Benjamin T.; Muhlfeld, Clint C.; Guy, Christopher S.; Downs, Christopher C.; Fredenberg, Wade A.

    2016-01-01

    There is an urgent need to consider more aggressive and direct interventions for the conservation of freshwater fishes that are threatened by invasive species, habitat loss, and climate change. Conservation introduction (moving a species outside its indigenous range to other areas where conditions are predicted to be more suitable) is one type of translocation strategy that fisheries managers can use to establish new conservation populations in areas of refugia. To date, however, there are few examples of successful conservation-based introductions. Many attempts fail to establish new populations—in part because environmental factors that might influence success are inadequately evaluated before the translocation is implemented. We developed a framework to assess the feasibility of rescuing threatened fish populations through translocation into historically unoccupied stream and lake habitats. The suitability of potential introduction sites was evaluated based on four major components: the recipient habitat, recipient community, donor population, and future threats. Specific questions were then developed to evaluate each major component. The final assessment was based on a scoring system that addressed each question by using criteria developed from characteristics representative of highly suitable habitats and populations. This framework was used to evaluate the proposed within-drainage translocation of three Bull Trout Salvelinus confluentus populations in Glacier National Park, Montana. Our results indicated that within-drainage translocation is a feasible strategy for conserving locally adapted populations of Bull Trout through the creation of new areas of refugia in Glacier National Park. The framework provides a flexible platform that can help managers make informed decisions for moving threatened fishes into new areas of refugia for conservation and recovery programs.

  6. Potential strategies for recovery of lake whitefish and lake herring stocks in eastern Lake Erie

    Science.gov (United States)

    Oldenburg, K.; Stapanian, M.A.; Ryan, P.A.; Holm, E.

    2007-01-01

    Lake Erie sustained large populations of ciscoes (Salmonidae: Coregoninae) 120 years ago. By the end of the 19th century, abundance of lake whitefish (Coregonus clupeaformis) had declined drastically. By 1925, the lake herring (a cisco) population (Coregonus artedii) had collapsed, although a limited lake herring fishery persisted in the eastern basin until the 1950s. In the latter part of the 20th century, the composition of the fish community changed as oligotrophication proceeded. Since 1984, a limited recovery of lake whitefish has occurred, however no recovery was evident for lake herring. Current ecological conditions in Lake Erie probably will not inhibit recovery of the coregonine species. Recovery of walleye (Sander vitreus) and efforts to rehabilitate the native lake trout (Salvelinus namaycush) in Lake Erie will probably assist recovery because these piscivores reduce populations of alewife (Alosa psuedoharengus) and rainbow smelt (Osmerus mordax), which inhibit reproductive success of coregonines. Although there are considerable spawning substrates available to coregonine species in eastern Lake Erie, eggs and fry would probably be displaced by storm surge from most shoals. Site selection for stocking or seeding of eggs should consider the reproductive life cycle of the stocked fish and suitable protection from storm events. Two potential sites in the eastern basin have been identified. Recommended management procedures, including commercial fisheries, are suggested to assist in recovery. Stocking in the eastern basin of Lake Erie is recommended for both species, as conditions are adequate and the native spawning population in the eastern basin is low. For lake herring, consideration should be given to match ecophenotypes as much as possible. Egg seeding is recommended. Egg seeding of lake whitefish should be considered initially, with fingerling or yearling stocking suggested if unsuccessful. Spawning stocks of whitefish in the western basin of Lake

  7. Abundance indices for determining the status of lake trout restoration in Michigan waters of Lake Superior

    Science.gov (United States)

    Hansen, Michael J.; Schorfhaar, Richard G.; Peck, James W.; Selgeby, James H.; Taylor, William W.

    1995-01-01

    Self-sustaining populations of lake trout Salvelinus namaycush have returned to most areas in Lake Superior, but progress toward achieving historic commercial yields has been difficult to measure because of unrecorded losses to predation by sea lamprey Petromyzon marinus and to fisheries. Consequently, we developed restoration targets (catch per effort, CPE; geometric mean number per kilometer of 114-mm stretch-meaure gill net during 1929-1943, when historic yields were sustained) from linear relationships between CPE in commercial and assessment fisheries in Michigan. Target CPEs for lake trout restoration were higher and less variable than the modern CPEs in all areas. Modern CPEs generally increased during the 1970s and early 1980s but declined during the late 1980s and early 1990s. Modern CPEs were highest in western Michigan from the Keweenaw Peninsula to Marquette (71 to 81% of target CPEs), but coefficients of variation (CV,SD/mean) of mean CPEs were 1.4 to 2.4 times greater than target CVs. Around Munising, the modern CPE was lower (41% of the target CPE), whereas the CV was 1.9 times greater than the target CV. Around Grand Marais, the modern CPE was lowest among all areas (17% of the target CPE), but the CV was nearly the same (1.1 times the target CV). In Whitefish Bay, the modern CPE was only 28% of the target CPE and the CV was 9.0 times greater, though the modern period was based on only the years 1979-1982 and 1984-1985. Further progress in restoration in most areas can be achieved only if fishery managers adequately protect existing stocks of wild fish from sea lamprey predation and fishery exploitation.

  8. Populations protection and territories management in nuclear emergency and post-accident situation

    International Nuclear Information System (INIS)

    for the management of post-accident consequences: agricultural activities and exit of the emergency stage (B. Cessac); 18 - presentation of the operational means of the GIE Groupe Intra (A. Cochard); 19 - synthetical presentation of the studies of post-accident management conditions in the milk industry (G. Machenaud); 20 - reconstruction of doses received by exposed populations (J.R. Jourdain); 21 - organisation of the health monitoring of populations after a radiological accident - presentation taken from the recommendations of the Codirpa's working group 'health stakes' (P. Pirard); 22 - losses indemnification in case of nuclear accident (M. Leger); 23 - post nuclear accident communication - reflections of the Codirpa's working group 'communication' (E. Bouchot); 24 - the ANCCLI's permanent group 'territories - post-accident' (M. Demet); 25 - experience feedback from the local information commission (CLI) 'Marcoule-Gard' in the management of a post-accident situation (J.P. Charre); 26 - commitment of intervening parties in the preparation to accident and post-accident situations: European experiences (T. Schneider); 27 - socio-cognitive exposure and risk assessment - the radio waves case (M. Poumadere). (J.S.)

  9. Fingerprints of environmental stressors in three selected Slovenian gravel-bed rivers: geochemical and isotopic approach

    Science.gov (United States)

    Kanduč, Tjaša; Kocman, David; Debeljak, Barbara; Mori, Nataša

    2016-04-01

    Rivers are severely impacted by a range of simultaneous processes including water pollution, flow and channel alteration, over-fishing, invasive species and climate change. Systematic studies of river water geochemistry provide important information on chemical weathering of bedrock/soil and natural anthropogenic processes that may control the dissolved chemical loads, while the isotopic studies of biological components of river systems (macrophytes, periphyton, heterotrophic biofilm, invertebrates, fish) contribute to the understanding how the system response to human impacts by means of functional response. In this contribution, insights in the fingerprints of various environmental stressors in three gravel-bed rivers (River Kamni\\vska Bistrica, River Idrijca and River Sava) in Slovenia, using geochemical and stable isotope approach are discussed. Gravel bed of all three rivers investigated is composed of carbonates and clastic rocks. The Sava and Kamni\\vska Bistrica Rivers have alpine high mountain snow-rain regime. The Idrijca River is a boundary river between the Adriatic and Black Sea catchments and has rain-snow discharge regime with torrential character. Geochemical methods (ICP-OES, IC, total alkalinity after Gran) and isotope mass - spectrometric methods (isotopic composition of dissolved inorganic carbon, particulate organic carbon and isotopic composition of carbon in carbonates) were used to evaluate biogeochemical processes in rivers. Isotopic composition of carbon and nitrogen of the moss Fontinalis antipyretica (the whole vegetative shoot) and isotopic composition of carbon of heterotrophic biofilm was also analyzed in order to better understand the fluxes and fractionation of carbon and nitrogen across trophic levels. Geochemical composition of all investigated rivers is HCO3--Ca2+-Mg2+ with different Mg2+/Ca2+ ratios as follows: around 0.33 for Kamni\\vska Bistrica and River Sava in Slovenia and above 0.75 for River Idrijca. In the Kamni

  10. Quantitative distribution of aquatic plant and animal communities in the Forsmark-area

    Energy Technology Data Exchange (ETDEWEB)

    Kautsky, H.; Plantman, P.; Borgiel, M. [Stockholm Univ. (Sweden). Dept. of Systems Ecology

    1999-12-15

    (boulders, rock) a luxuriant growth of the bladder wrack (Fucus vesiculosus) could be seen. Also, the moss Fontinalis dalecarlica was not unusual. This moss is frequently observed in the Gulf of Bothnia but does not occur in the Baltic proper. Among the animals, the blue mussel (Mytilus edulis) was to a large extent missing, although suitable substrate was present. In the Bothnian Sea the marine mussel Mytilus extends up to the Northern Quark, but usually only scattered, few individuals are found at each site along the whole coast. The blue mussel never has the same mass-occurrence as can be observed in the Stockholm archipelago and further south in the Baltic proper. Thus, the ecosystem of the SFR-area has a function somewhat different from the Baltic proper as the filter feeders lack to a large extent. The species biomass was determined by collecting 54 quantitative samples (usually 12 samples per transect). At comparable depths, when excluding the bladder wrack (Fucus vesiculosus) and the blue mussel (Mytilus edulis) the total depth distribution of plant and animal biomass was similar those of the Graesoe-Singoe area (ranging between 30-60 g dry weight m{sup -2} of plants and 20-50 g of animals). However, the total biomass of both the bladder wrack (Fucus vesiculosus) and the filter feeding blue mussel (Mytilus edulis) was considerable lower in the Forsmark area. This can to some extent be explained by the difference in dominating substrate (mostly rocky) as well as a larger influence from the Baltic proper in the Graesoe-Singoe area. For the low amounts of Mytilus see explanation given above.

  11. An ecological risk assessment of the exposure and effects of 2,4-D acid to rainbow trout (Onchorhyncus mykiss)

    Science.gov (United States)

    Fairchild, J.F.; Feltz, K.P.; Allert, A.L.; Sappington, L.C.; Nelson, K.J.; Valle, J.A.

    2009-01-01

    30-day safety factor of 559 (e.g., 76/0.163). Assessment of the exposure and response data presented herein indicates that use of 2,4-D acid for invasive weed control in aquatic and terrestrial habitats poses no substantial risk to growth or survival of rainbow trout or other salmonids, including the threatened bull trout (Salvelinus confluentus). ?? 2009 US Government.

  12. An ecological risk assessment of the acute and chronic effects of the herbicide clopyralid to rainbow trout (Oncorhynchus mykiss)

    Science.gov (United States)

    Fairchild, J.F.; Allert, A.L.; Feltz, K.P.; Nelson, K.J.; Valle, J.A.

    2009-01-01

    Clopyralid (3,6-dichloro-2-pyridinecarboxylic acid) is a pyridine herbicide frequently used to control invasive, noxious weeds in the northwestern United States. Clopyralid exhibits low acute toxicity to fish, including the rainbow trout (Oncorhynchus mykiss) and the threatened bull trout (Salvelinus confluentus). However, there are no published chronic toxicity data for clopyralid and fish that can be used in ecological risk assessments. We conducted 30-day chronic toxicity studies with juvenile rainbow trout exposed to the acid form of clopyralid. The 30-day maximum acceptable toxicant concentration (MATC) for growth, calculated as the geometric mean of the no observable effect concentration (68 mg/L) and the lowest observable effect concentration (136 mg/L), was 96 mg/L. No mortality was measured at the highest chronic concentration tested (273 mg/L). The acute:chronic ratio, calculated by dividing the previously published 96-h acutely lethal concentration (96-h ALC50; 700 mg/L) by the MATC was 7.3. Toxicity values were compared to a four-tiered exposure assessment profile assuming an application rate of 1.12 kg/ha. The Tier 1 exposure estimation, based on direct overspray of a 2-m deep pond, was 0.055 mg/L. The Tier 2 maximum exposure estimate, based on the Generic Exposure Estimate Concentration model (GEENEC), was 0.057 mg/L. The Tier 3 maximum exposure estimate, based on previously published results of the Groundwater Loading Effects of Agricultural Management Systems model (GLEAMS), was 0.073 mg/L. The Tier 4 exposure estimate, based on published edge-of-field monitoring data, was estimated at 0.008 mg/L. Comparison of toxicity data to estimated environmental concentrations of clopyralid indicates that the safety factor for rainbow trout exposed to clopyralid at labeled use rates exceeds 1000. Therefore, the herbicide presents little to no risk to rainbow trout or other salmonids such as the threatened bull trout. ?? 2009 US Government.

  13. Successional change in the Lake Superior fish community: population trends in ciscoes, rainbow smelt, and lake trout, 1958-2008

    Science.gov (United States)

    Gorman, Owen T.

    2012-01-01

    The Lake Superior fish community underwent massive changes in the second half of the 20th century. Those changes are largely reflected in changes in abundance of the adults of principal prey species, the ciscoes (Coregonus spp.), the invasive rainbow smelt (Osmerus mordax), and the principal predator, lake trout (Salvelinus namaycush). To better understand changes in species abundances, a comprehensive series of gillnet and bottom trawl data collected from 1958 to 2008 were examined. In the late 1950s/early 1960s, smelt abundance was at its maximum, wild lake trout was at its minimum, and an abundance of hatchery lake trout was increasing rapidly. The bloater (Coregonus hoyi) was the prevalent cisco in the lake; abundance was more than 300% greater than the next most abundant cisco, shortjaw cisco (C. zenithicus), followed by kiyi (C. kiyi) and lake cisco (C. artedi). By the mid-1960s, abundance of hatchery lake trout was nearing maximum, smelt abundance was beginning to decline, and abundances of all ciscoes declined, but especially that of shortjaw cisco and kiyi. By the late 1970s, recovery of wild lake trout stocks was well underway and abundances of hatchery lake trout and smelt were declining and the ciscoes were reaching their nadir. During 1980–1990, the fish community underwent a dramatic shift in organization and structure. The rapid increase in abundance of wild lake trout, concurrent with a rapid decline in hatchery lake trout, signaled the impending recovery. Rainbow smelt abundance dropped precipitously and within four years, lake cisco and bloater populations rebounded on the heels of a series of strong recruitment events. Kiyi populations showed signs of recovery by 1989, and shortjaw by 2000, though well below historic maximum abundances. High abundance of adult smelt prior to 1980 appears to be the only factor linked to recruitment failure in the ciscoes. Life history traits of the cisco species were examined to better understand their different

  14. Captive Rearing Initiative for Salmon River Chinook Salmon, 1999 Progress Report.

    Energy Technology Data Exchange (ETDEWEB)

    Hassemer, Peter F.

    2001-04-01

    these five were spawned out, one was partially spawned, and three died before depositing eggs. However, much of the spawning related behavior observed involved female chinook salmon paired with male bull trout Salvelinus confluentus. Two female carcasses from the East Fork Salmon River were recovered and examined for egg retention. One of these had spawned and one had not.

  15. Methow and Columbia Rivers studies: summary of data collection, comparison of database structure and habitat protocols, and impact of additional PIT tag interrogation systems to survival estimates, 2008-2012

    Science.gov (United States)

    Martens, Kyle D.; Tibbits, Wesley T.; Watson, Grace A.; Newsom, Michael A.; Connolly, Patrick J.

    2014-01-01

    The U.S. Geological Survey (USGS) received funding from the Bureau of Reclamation (Reclamation) to provide monitoring and evaluation on the effectiveness of stream restoration efforts by Reclamation in the Methow River watershed. This monitoring and evaluation program is designed to partially fulfill Reclamation’s part of the 2008 Biological Opinion for the Federal Columbia River Power System that includes a Reasonable and Prudent Alternative (RPA) to protect listed salmon and steelhead across their life cycle. The target species in the Methow River for the restoration effort include Upper Columbia River (UCR) spring Chinook salmon (Oncorhynchus tshawytscha), UCR steelhead (Oncorhynchus mykiss), and bull trout (Salvelinus confluentus), which are listed as threatened or endangered under the Endangered Species Act. Since 2004, the USGS has completed two projects of monitoring and evaluation in the Methow River watershed. The first project focused on the evaluation of barrier removal and steelhead recolonization in Beaver Creek with Libby and Gold Creeks acting as controls. The majority of this work was completed by 2008, although some monitoring continued through 2012. The second project (2008–2012) evaluated the use and productivity of the middle Methow River reach (rkm 65–80) before the onset of multiple off-channel restoration projects planned by the Reclamation and Yakama Nation. The upper Methow River (upstream of rkm 80) and Chewuch River serve as reference reaches and the Methow River downstream of the Twisp River (downstream of rkm 65) serves as a control reach. Restoration of the M2 reach was initiated in 2012 and will be followed by a multi-year, intensive post-evaluation period. This report is comprised of three chapters covering different aspects of the work completed by the USGS. The first chapter is a review of data collection that documents the methods used and summarizes the work done by the USGS from 2008 through 2012. This data summary was

  16. Development and Application of a Decision Support System for Water Management Investigations in the Upper Yakima River, Washington

    Science.gov (United States)

    Bovee, Ken D.; Waddle, Terry J.; Talbert, Colin; Hatten, James R.; Batt, Thomas R.

    2008-01-01

    The Yakima River Decision Support System (YRDSS) was designed to quantify and display the consequences of different water management scenarios for a variety of state variables in the upper Yakima River Basin, located in central Washington. The impetus for the YRDSS was the Yakima River Basin Water Storage Feasibility Study, which investigated alternatives for providing additional water in the basin for threatened and endangered fish, irrigated agriculture, and municipal water supply. The additional water supplies would be provided by combinations of water exchanges, pumping stations, and off-channel storage facilities, each of which could affect the operations of the Bureau of Reclamation's (BOR) five headwaters reservoirs in the basin. The driver for the YRDSS is RiverWare, a systems-operations model used by BOR to calculate reservoir storage, irrigation deliveries, and streamflow at downstream locations resulting from changes in water supply and reservoir operations. The YRDSS uses output from RiverWare to calculate and summarize changes at 5 important flood plain reaches in the basin to 14 state variables: (1) habitat availability for selected life stages of four salmonid species, (2) spawning-incubation habitat persistence, (3) potential redd scour, (4) maximum water temperatures, (5) outmigration for bull trout (Salvelinus confluentus) from headwaters reservoirs, (6) outmigration of salmon smolts from Cle Elum Reservoir, (7) frequency of beneficial overbank flooding, (8) frequency of damaging flood events, (9) total deliverable water supply, (10) total water supply deliverable to junior water rights holders, (11) end-of-year reservoir carryover, (12) potential fine sediment transport rates, (13) frequency of events capable of armor layer disruption, and (14) geomorphic work performed during each water year. Output of the YRDSS consists of a series of conditionally formatted scoring tables, wherein the changes to a state variable resulting from an operational

  17. Radiological impact of the nuclear power plant accident on freshwater fish in Fukushima: An overview of monitoring results.

    Science.gov (United States)

    Wada, Toshihiro; Tomiya, Atsushi; Enomoto, Masahiro; Sato, Toshiyuki; Morishita, Daigo; Izumi, Shigehiko; Niizeki, Kouji; Suzuki, Shunji; Morita, Takami; Kawata, Gyo

    2016-01-01

    Radionuclide ((131)I, (134)Cs, and (137)Cs) concentrations of monitored freshwater fish species collected from different habitats (rivers, lakes, and culture ponds) in Fukushima Prefecture during March 2011-December 2014 (total 16 species, n = 2692) were analyzed to present a detailed description of radionuclide contamination after the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident, and to elucidate species-specific spatiotemporal declining trends of (137)Cs concentration for their respective habitats. Low concentrations of (131)I (≤24 Bq kg(-1)-wet) were detected from only 11 samples collected during March-June 2011, demonstrating that (131)I transferred to freshwater fish were not intense. In river and lake fishes, a more gradual decrease and higher radiocesium ((134)Cs, (137)Cs) concentrations were observed than in culture pond fishes, which strongly implied that radiocesium in freshwater fish species was mainly bioaccumulated through the food web in the wild. During 2011-2014, percentages above the Japanese regulatory limit of 100 Bq kg(-1)-wet for radiocesium in river and lake fish (14.0% and 39.6%, respectively) were higher than in monitored marine fish (9.9%), indicating longer-term contamination of freshwater fish species, especially in lakes. Higher radiocesium concentrations (maximum 18.7 kBq kg(-1)-wet in Oncorhynchus masou) were found in the northwestern areas from the FDNPP with higher deposition. However, radiocesium contamination levels were regarded as 1-2 orders of magnitude less than those after the Chernobyl accident. Lagged increase of (137)Cs concentration and longer ecological half-lives (Teco: 1.2-2.6 y in the central part of Fukushima Prefecture) were observed in carnivorous salmonids (O. masou, Salvelinus leucomaenis), whereas a rapid increase and decrease of (137)Cs concentration and shorter Teco (0.99 and 0.69 y) were found in herbivorous and planktivorous osmerids (Plecoglossus altivelis, Hypomesus nipponensis) with

  18. Increase in lake trout reproduction in lake huron following the collapse of alewife: Relief from thiamine deficiency or larval predation?

    Science.gov (United States)

    Fitzsimons, J.D.; Brown, S.; Brown, L.; Honeyfield, D.; He, J.; Johnson, J.E.

    2010-01-01

    In the Great Lakes there is still uncertainty as to the population level effects of a thiamine deficiency on salmonines caused by high consumption of alewives Alosa pseudoharengus. A resurgence of lake trout Salvelinus namaycush reproduction in Lake Huron following the crash of alewife stocks between 2002 and 2004 provided an opportunity to evaluate the relative effects of this crash on reproduction through relief from either alewife mediated thiamine deficiency or alewife predation on larval lake trout relative to possible changes in the size of the lake trout spawning stock. Changes in mean lake trout egg thiamine concentration post crash at one spawning reef in Parry Sound, wheremean thiamine concentration increased by almost two fold, were consistent with diet switching from alewives to rainbow smelt Osmerus mordax, the next most abundant prey fish in Lake Huron. Although thiamine levels for lake trout collected at a second reef in Parry Sound did not change post-crash, levels both pre- and post-crash were consistent with a rainbow smelt diet. A reef specific fry emergence index was found to be positively related to reef specific egg thiamine concentration but negatively related to reef specific occurrence of EMS, a thiamine deficiency related mortality syndrome. We found little evidence for overlap between the timing of spring shoreward migration of alewives and lake trout emergence, suggesting that relief from alewife predation effects had relatively little effect on the observed increase in lake trout recruitment. Numbers of spawners in the north, north-central, and southern zones of the lake increased from 2000 onwards. Overall the abundance post-2003 was higher than from pre-2004, suggesting that spawner abundance may also have contributed to increased lake trout reproduction. However, predicted numbers of spawners and measured abundance of wild recruits in assessment gear were poorly correlated suggesting that the increase in reproduction was not totally

  19. Bull Trout Life History, Genetics, Habitat Needs, and Limiting Factors in Central and Northeast Oregon, Annual Report 2001.

    Energy Technology Data Exchange (ETDEWEB)

    Hemmingsen, Alan R.; Gunckel, Stephanie L.; Sankovich, Paul M.; Howell, Philip J.

    2002-12-01

    Bull trout Salvelinus confluentus exhibit a number of life history strategies. Stream-resident bull trout complete their life cycle in their natal tributaries. Migratory bull trout spawn in tributary streams where juvenile fish usually spend from one to four years before migrating to either a larger river (fluvial) or lake (adfluvial) where they rear before returning to the tributary stream to spawn (Fraley and Shepard 1989). These migratory forms occur where conditions allow movement from spawning locations to downstream waters that provide greater foraging opportunities (Dunham and Rieman 1999). Resident and migratory forms may occur together, and either form can produce resident or migratory offspring (Rieman and McIntyre 1993). The ability to migrate is important to the persistence of local bull trout populations (Rieman and McIntyre 1993). The identification of migratory corridors can help focus habitat protection efforts. Determining the life history form(s) that comprise local populations, the timing of seasonal movements, and the geographic extent of these movements are critical to bull trout protection and recovery efforts. This section describes work accomplished in 2001 that continued to address two objectives of this project. These objectives are (1) determine the distribution of juvenile and adult bull trout and habitats associated with that distribution, and (2) determine fluvial and resident bull trout life history patterns. Completion of these objectives is intended through studies of bull trout in the Grande Ronde, Walla Walla, and John Day basins. These basins were selected because they provide a variety of habitats, from relatively degraded to pristine, and bull trout populations were thought to vary from relatively depressed to robust. In the Grande Ronde and Walla Walla basins, we continued to monitor the movements of bull trout with radio transmitters applied in 1998 (Hemmingsen, Bellerud, Gunckel and Howell 2001) and 1999 (Hemmingsen, Gunckel

  20. Captive Rearing Initiative for Salmon River Chinook Salmon, 1998-1999 Progress Report.

    Energy Technology Data Exchange (ETDEWEB)

    Hassemer, Peter F.

    2001-04-01

    these five were spawned out, one was partially spawned, and three died before depositing eggs. However, much of the spawning related behavior observed involved female chinook salmon paired with male bull trout Salvelinus confluentus. Two female carcasses from the East Fork Salmon River were recovered and examined for egg retention. One of these had spawned and one had not.

  1. Bull Trout Population Assessment in the Columbia River Gorge : Annual Report 2000.

    Energy Technology Data Exchange (ETDEWEB)

    Byrne, Jim; McPeak, Ron

    2001-02-01

    We summarized existing knowledge regarding the known distribution of bull trout (Salvelinus confluentus) across four sub-basins in the Columbia River Gorge in Washington. The Wind River, Little White Salmon River, White Salmon River, and the Klickitat River sub-basins were analyzed. Cold water is essential to the survival, spawning, and rearing of bull trout. We analyzed existing temperature data, installed Onset temperature loggers in the areas of the four sub-basins where data was not available, and determined that mean daily water temperatures were <15 C and appropriate for spawning and rearing of bull trout. We snorkel surveyed more than 74 km (46.25 mi.) of rivers and streams in the four sub-basins (13.8 km at night and 60.2 km during the day) and found that night snorkeling was superior to day snorkeling for locating bull trout. Surveys incorporated the Draft Interim Protocol for Determining Bull Trout Presence (Peterson et al. In Press). However, due to access and safety issues, we were unable to randomly select sample sites nor use block nets as recommended. Additionally, we also implemented the Bull Trout/Dolly Varden sampling methodology described in Bonar et al. (1997). No bull trout were found in the Wind River, Little White Salmon, or White Salmon River sub-basins. We found bull trout in the West Fork Klickitat drainage of the Klickitat River Sub-basin. Bull trout averaged 6.7 fish/100m{sup 2} in Trappers Creek, 2.6 fish/100m{sup 2} on Clearwater Creek, and 0.4 fish/100m{sup 2} in Little Muddy Creek. Bull trout was the only species of salmonid encountered in Trappers Creek and dominated in Clearwater Creek. Little Muddy Creek was the only creek where bull trout and introduced brook trout occurred together. We found bull trout only at night and typically in low flow regimes. A single fish, believed to be a bull trout x brook trout hybrid, was observed in the Little Muddy Creek. Additional surveys are needed in the West Fork Klickitat and mainstem

  2. Piscivorous fish exhibit temperature-influenced binge feeding during an annual prey pulse.

    Science.gov (United States)

    Furey, Nathan B; Hinch, Scott G; Mesa, Matthew G; Beauchamp, David A

    2016-09-01

    Understanding the limits of consumption is important for determining trophic influences on ecosystems and predator adaptations to inconsistent prey availability. Fishes have been observed to consume beyond what is sustainable (i.e. digested on a daily basis), but this phenomenon of hyperphagia (or binge-feeding) is largely overlooked. We expect hyperphagia to be a short-term (1-day) event that is facilitated by gut volume providing capacity to store consumed food during periods of high prey availability to be later digested. We define how temperature, body size and food availability influence the degree of binge-feeding by comparing field observations with laboratory experiments of bull trout (Salvelinus confluentus), a large freshwater piscivore that experiences highly variable prey pulses. We also simulated bull trout consumption and growth during salmon smolt outmigrations under two scenarios: 1) daily consumption being dependent upon bioenergetically sustainable rates and 2) daily consumption being dependent upon available gut volume (i.e. consumption is equal to gut volume when empty and otherwise 'topping off' based on sustainable digestion rates). One-day consumption by laboratory-held bull trout during the first day of feeding experiments after fasting exceeded bioenergetically sustainable rates by 12- to 87-fold at low temperatures (3 °C) and by  ˜1·3-fold at 20 °C. The degree of binge-feeding by bull trout in the field was slightly reduced but largely in agreement with laboratory estimates, especially when prey availability was extremely high [during a sockeye salmon (Oncorhynchus nerka) smolt outmigration and at a counting fence where smolts are funnelled into high densities]. Consumption by bull trout at other settings were lower and more variable, but still regularly hyperphagic. Simulations demonstrated the ability to binge-feed increased cumulative consumption (16-32%) and cumulative growth (19-110%) relative to only feeding at

  3. Using accelerated life testing procedures to compare the relative sensitivity of rainbow trout and the federally listed threatened bull trout to three commonly used rangeland herbicides (picloram, 2,4-D, and clopyralid)

    Science.gov (United States)

    Fairchild, J.F.; Allert, A.; Sappington, L.S.; Nelson, K.J.; Valle, J.

    2008-01-01

    We conducted 96-h static acute toxicity studies to evaluate the relative sensitivity of juveniles of the threatened bull trout (Salvelinus confluentus) and the standard cold-water surrogate rainbow trout (Onchorhyncus mykiss) to three rangeland herbicides commonly used for controlling invasive weeds in the northwestern United States. Relative species sensitivity was compared using three procedures: standard acute toxicity testing, fractional estimates of lethal concentrations, and accelerated life testing chronic estimation procedures. The acutely lethal concentrations (ALC) resulting in 50% mortality at 96 h (96-h ALC50s) were determined using linear regression and indicated that the three herbicides were toxic in the order of picloram acid > 2,4-D acid > clopyralid acid. The 96-h ALC50 values for rainbow trout were as follows: picloram, 41 mg/L; 2.4-D, 707 mg/L; and clopyralid, 700 mg/L. The 96-h ALC50 values for bull trout were as follows: picloram, 24 mg/L; 2.4-D, 398 mg/L; and clopyralid, 802 mg/L. Fractional estimates of safe concentrations, based on 5% of the 96-h ALC50, were conservative (overestimated toxicity) of regression-derived 96-h ALC5 values by an order of magnitude. Accelerated life testing procedures were used to estimate chronic lethal concentrations (CLC) resulting in 1% mortality at 30 d (30-d CLC1) for the three herbicides: picloram (1 mg/L rainbow trout, 5 mg/L bull trout), 2,4-D (56 mg/L rainbow trout, 84 mg/L bull trout), and clopyralid (477 mg/L rainbow trout; 552 mg/L bull trout). Collectively, the results indicated that the standard surrogate rainbow trout is similar in sensitivity to bull trout. Accelerated life testing procedures provided cost-effective, statistically defensible methods for estimating safe chronic concentrations (30-d CLC1s) of herbicides from acute toxicity data because they use statistical models based on the entire mortality:concentration: time data matrix. ?? 2008 SETAC.

  4. Kootenai River Fisheries Investigations; Rainbow and Bull Trout Recruitment, 2002-2003 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Walters, Jody P.

    2004-01-01

    Rainbow trout Oncorhynchus mykiss provide the most important sport fishery in the Kootenai River, Idaho, but densities and catch rates are low. Low recruitment is one possible factor limiting the rainbow trout population. Bull trout Salvelinus confluentus also exist in the Kootenai River, but little is known about this population. Research reported here addresses the following objectives for the Kootenai River, Idaho: increase rainbow trout recruitment, identify rainbow and bull trout spawning tributaries and migration timing, establish baseline data on bull trout redd numbers in tributaries, and improve the rainbow trout population size structure. Six adult rainbow trout were moved to spawning habitat upstream of a potential migration barrier on Caboose Creek, but numbers of redds and age-0 out-migrants did not appear to increase relative to a reference stream. Measurements taken on the Moyie River indicated the gradient is inadequate to deliver suitable flows to a proposed rainbow trout spawning channel. Summer water temperatures measured in the Deep Creek drainage sometimes exceeded 24 C, higher than those reported as suitable for rainbow trout. Radio-tagged rainbow trout were located in Boulder Creek during the spring spawning season, and bull trout were located in the Moyie River and O'Brien Creek, Montana in the fall. Bull trout spawning migration timing was related to increases in Kootenai River flows. Bull trout redd surveys documented 19 redds on Boulder Creek and North and South Callahan creeks. Fall 2002 electrofishing showed that the Kootenai River rainbow trout proportional stock density was 54, higher than prior years when more liberal fishing regulations were in effect. Boulder Creek produces the highest number of age-0 rainbow trout out-migrants upstream of Bonners Ferry, but the survival rate of these out-migrants upon reaching the Kootenai River is unknown. Determining juvenile survival rates and sources of mortality could aid management

  5. A synthesis of ecological and fish-community changes in Lake Ontario, 1970-2000

    Science.gov (United States)

    Mills, E.L.; Casselman, J.M.; Dermott, R.; Fitzsimons, J.D.; Gal, G.; Holeck, K. T.; Hoyle, J.A.; Johannsson, O.E.; Lantry, B.F.; Makarewicz, J.C.; Millard, E.S.; Munawar, I.F.; Munawar, M.; O'Gorman, R.; Owens, R.W.; Rudstam, L. G.; Schaner, T.; Stewart, T.J.

    2005-01-01

    We assessed stressors associated with ecological and fishcommunity changes in Lake Ontario since 1970, when the first symposium on Salmonid Communities in Oligotrophic Lakes (SCOL I) was held (J. Fish. Res. Board Can. 29: 613-616). Phosphorus controls implemented in the early 1970s were undeniably successful; lower food-web studies showed declines in algal abundance and epilimnetic zooplankton production and a shift in pelagic primary productivity toward smaller organisms. Stressors on the fish community prior to 1970 such as exploitation, sea lamprey (Petromyzon marinus) predation, and effects of nuisance populations of alewife (Alosa pseudoharengus) were largely ameliorated by the 1990s. The alewife became a pivotal species supporting a multi-million-dollar salmonid sport fishery, but alewife-induced thiamine deficiency continued to hamper restoration and sustainability of native lake trout (Salvelinus namaycush). Expanding salmonine populations dependent on alewife raised concerns about predator demand and prey supply, leading to reductions in salmonine stocking in the early 1990s. Relaxation of the predation impact by alewives and their shift to deeper water allowed recovery of native fishes such as threespine stickleback (Gasterosteus aculeatus) and emerald shiner (Notropis atherinoides). The return of the Lake Ontario ecosystem to historical conditions has been impeded by unplanned introductions. Establishment of Dreissena spp. led to increased water clarity and increased vectoring of lower trophic-level production to benthic habitats and contributed to the collapse of Diporeia spp. populations, behavioral modifications of key fish species, and the decline of native lake whitefish (Coregonus clupeaformis). Despite reduced productivity, exotic-species introductions, and changes in the fish community, offshore Mysis relicta populations remained relatively stable. The effects of climate and climate change on the population abundance and dynamics of Lake Ontario

  6. Comparisons of likelihood and machine learning methods of individual classification

    Science.gov (United States)

    Guinand, B.; Topchy, A.; Page, K.S.; Burnham-Curtis, M. K.; Punch, W.F.; Scribner, K.T.

    2002-01-01

    Classification methods used in machine learning (e.g., artificial neural networks, decision trees, and k-nearest neighbor clustering) are rarely used with population genetic data. We compare different nonparametric machine learning techniques with parametric likelihood estimations commonly employed in population genetics for purposes of assigning individuals to their population of origin (“assignment tests”). Classifier accuracy was compared across simulated data sets representing different levels of population differentiation (low and high FST), number of loci surveyed (5 and 10), and allelic diversity (average of three or eight alleles per locus). Empirical data for the lake trout (Salvelinus namaycush) exhibiting levels of population differentiation comparable to those used in simulations were examined to further evaluate and compare classification methods. Classification error rates associated with artificial neural networks and likelihood estimators were lower for simulated data sets compared to k-nearest neighbor and decision tree classifiers over the entire range of parameters considered. Artificial neural networks only marginally outperformed the likelihood method for simulated data (0–2.8% lower error rates). The relative performance of each machine learning classifier improved relative likelihood estimators for empirical data sets, suggesting an ability to “learn” and utilize properties of empirical genotypic arrays intrinsic to each population. Likelihood-based estimation methods provide a more accessible option for reliable assignment of individuals to the population of origin due to the intricacies in development and evaluation of artificial neural networks. In recent years, characterization of highly polymorphic molecular markers such as mini- and microsatellites and development of novel methods of analysis have enabled researchers to extend investigations of ecological and evolutionary processes below the population level to the level of

  7. Factors affecting biotic mercury concentrations and biomagnification through lake food webs in the Canadian high Arctic

    International Nuclear Information System (INIS)

    In temperate regions of Canada, mercury (Hg) concentrations in biota and the magnitude of Hg biomagnification through food webs vary between neighboring lakes and are related to water chemistry variables and physical lake features. However, few studies have examined factors affecting the variable Hg concentrations in landlocked Arctic char (Salvelinus alpinus) or the biomagnification of Hg through their food webs. We estimated the food web structure of six high Arctic lakes near Resolute Bay, Nunavut, Canada, using stable carbon (δ13C) and nitrogen (δ15N) isotopes and measured Hg (total Hg (THg) in char, the only fish species, and methylmercury (MeHg) in chironomids and zooplankton) concentrations in biota collected in 2010 and 2011. Across lakes, δ13C showed that benthic carbon (chironomids) was the dominant food source for char. Regression models of log Hg versus δ15N (of char and benthic invertebrates) showed positive and significant slopes, indicting Hg biomagnification in all lakes, and higher slopes in some lakes than others. However, no principal components (PC) generated using all water chemistry data and physical characteristics of the lakes predicted the different slopes. The PC dominated by aqueous ions was a negative predictor of MeHg concentrations in chironomids, suggesting that water chemistry affects Hg bioavailability and MeHg concentrations in these lower-trophic-level organisms. Furthermore, regression intercepts were predicted by the PCs dominated by catchment area, aqueous ions, and MeHg. Weaker relationships were also found between THg in small char or MeHg in pelagic invertebrates and the PCs dominated by catchment area, and aqueous nitrate and MeHg. Results from these high Arctic lakes suggest that Hg biomagnification differs between systems and that their physical and chemical characteristics affect Hg concentrations in lower-trophic-level biota. - Highlights: • Mercury (Hg) in Arctic char and invertebrates from 6 Arctic lakes were

  8. Adaptive responses of energy storage and fish life histories to climatic gradients.

    Science.gov (United States)

    Giacomini, Henrique C; Shuter, Brian J

    2013-12-21

    Energy storage is a common adaptation of fish living in seasonal environments. For some species, the energy accumulated during the growing season, and stored primarily as lipids, is crucial to preventing starvation mortality over winter. Thus, in order to understand the adaptive responses of fish life history to climate, it is important to determine how energy should be allocated to storage and how it trades off with the other body components that contribute to fitness. In this paper, we extend previous life history theory to include an explicit representation of how the seasonal allocation of energy to storage acts as a constraint on fish growth. We show that a strategy that privileges allocation to structural mass in the first part of the growing season and switches to storage allocation later on, as observed empirically in several fish species, is the strategy that maximizes growth efficiency and hence is expected to be favored by natural selection. Stochastic simulations within this theoretical framework demonstrate that the relative performance of this switching strategy is robust to a wide range of fluctuations in growing season length, and to moderate short-term (i.e., daily) fluctuations in energy intake and/or expenditure within the growing season. We then integrate this switching strategy with a biphasic growth modeling framework to predict typical growth rates of walleye Sander vitreus, a cool water species, and lake trout Salvelinus namaycush, a cold water specialist, across a climatic gradient in North America. As predicted, growth rates increased linearly with the duration of the growing season. Regression line intercepts were negative, indicating that growth can only occur when growing season length exceeds a threshold necessary to produce storage for winter survival. The model also reveals important differences between species, showing that observed growth rates of lake trout are systematically higher than those of walleye in relatively colder lakes

  9. Lake Pend Oreille Predation Research, Annual Report 2002-2003.

    Energy Technology Data Exchange (ETDEWEB)

    Bassista, Thomas

    2004-02-01

    During August 2002 we conducted a hydroacoustic survey to enumerate pelagic fish >406 mm in Lake Pend Oreille, Idaho. The purpose of this survey was to determine a collective lakewide biomass estimate of pelagic bull trout Salvelinus confluentus, rainbow trout Oncorhynchus mykiss, and lake trout S. namaycush and compare it to pelagic prey (kokanee salmon O. nerka) biomass. By developing hydroacoustic techniques to determine the pelagic predator to prey ratio, we can annually monitor their balance. Hydroacoustic surveys were also performed during December 2002 and February 2003 to investigate the effectiveness of autumn and winter surveys for pelagic predators. The inherent problem associated with hydroacoustic sampling is the inability to directly identify fish species. Therefore, we utilized sonic tracking techniques to describe rainbow trout and lake trout habitat use during our winter hydroacoustic survey to help identify fish targets from the hydroacoustic echograms. During August 2002 we estimated there were 39,044 pelagic fish >406 mm in Lake Pend Oreille (1.84 f/ha). Based on temperature and depth utilization, two distinct groups of pelagic fish >406 mm were located during August; one group was located between 10 and 35 m and the other between 40 and 70 m. The biomass for pelagic fish >406 mm during August 2002 was 73 t (metric ton). This would account for a ratio of 1 kg of pelagic predator for every 2.63 kg of kokanee prey, assuming all pelagic fish >406 mm are predators. During our late fall and winter hydroacoustic surveys, pelagic fish >406 mm were observed at lake depths between 20 and 90 m. During late fall and winter, we tracked three rainbow trout (168 habitat observations) and found that they mostly occupied pelagic areas and predominantly stayed within the top 10 m of the water column. During late fall (one lake trout) and winter (four lake trout), we found that lake trout (184 habitat observations) utilized benthic-nearshore areas 65% of the time

  10. Piscivorous fish exhibit temperature-influenced binge feeding during an annual prey pulse

    Science.gov (United States)

    Furey, Nathan B.; Hinch, Scott G.; Mesa, Matthew G.; Beauchamp, David A.

    2016-01-01

    Understanding the limits of consumption is important for determining trophic influences on ecosystems and predator adaptations to inconsistent prey availability. Fishes have been observed to consume beyond what is sustainable (i.e. digested on a daily basis), but this phenomenon of hyperphagia (or binge-feeding) is largely overlooked. We expect hyperphagia to be a short-term (1-day) event that is facilitated by gut volume providing capacity to store consumed food during periods of high prey availability to be later digested.We define how temperature, body size and food availability influence the degree of binge-feeding by comparing field observations with laboratory experiments of bull trout (Salvelinus confluentus), a large freshwater piscivore that experiences highly variable prey pulses. We also simulated bull trout consumption and growth during salmon smolt outmigrations under two scenarios: 1) daily consumption being dependent upon bioenergetically sustainable rates and 2) daily consumption being dependent upon available gut volume (i.e. consumption is equal to gut volume when empty and otherwise ‘topping off’ based on sustainable digestion rates).One-day consumption by laboratory-held bull trout during the first day of feeding experiments after fasting exceeded bioenergetically sustainable rates by 12- to 87-fold at low temperatures (3 °C) and by  ˜1·3-fold at 20 °C. The degree of binge-feeding by bull trout in the field was slightly reduced but largely in agreement with laboratory estimates, especially when prey availability was extremely high [during a sockeye salmon (Oncorhynchus nerka) smolt outmigration and at a counting fence where smolts are funnelled into high densities]. Consumption by bull trout at other settings were lower and more variable, but still regularly hyperphagic.Simulations demonstrated the ability to binge-feed increased cumulative consumption (16–32%) and cumulative growth (19–110%) relative to only feeding at

  11. Changing numbers of spawning cutthroat trout in tributary streams of Yellowstone Lake and estimates of grizzly bears visiting streams from DNA

    Science.gov (United States)

    Haroldson, M.A.; Gunther, K.A.; Reinhart, D.P.; Podruzny, S.R.; Cegelski, C.; Waits, L.; Wyman, T.C.; Smith, J.

    2005-01-01

    Spawning Yellowstone cutthroat trout (Oncorhynchus clarki) provide a source of highly digestible energy for grizzly bears (Ursus arctos) that visit tributary streams to Yellowstone Lake during the spring and early summer. During 1985–87, research documented grizzly bears fishing on 61% of the 124 tributary streams to the lake. Using track measurements, it was estimated that a minimum of 44 grizzly bears fished those streams annually. During 1994, non-native lake trout (Salvelinus namaycush) were discovered in Yellowstone Lake. Lake trout are efficient predators and have the potential to reduce the native cutthroat population and negatively impact terrestrial predators that use cutthroat trout as a food resource. In 1997, we began sampling a subset of streams (n = 25) from areas of Yellowstone Lake surveyed during the previous study to determine if changes in spawner numbers or bear use had occurred. Comparisons of peak numbers and duration suggested a considerable decline between study periods in streams in the West Thumb area of the lake. The apparent decline may be due to predation by lake trout. Indices of bear use also declined on West Thumb area streams. We used DNA from hair collected near spawning streams to estimate the minimum number of bears visiting the vicinity of spawning streams. Seventy-four individual bears were identified from 429 hair samples. The annual number of individuals detected ranged from 15 in 1997 to 33 in 2000. Seventy percent of genotypes identified were represented by more than 1 sample, but only 31% of bears were documented more than 1 year of the study. Sixty-two (84%) bears were only documented in 1 segment of the lake, whereas 12 (16%) were found in 2–3 lake segments. Twenty-seven bears were identified from hair collected at multiple streams. One bear was identified on 6 streams in 2 segments of the lake and during 3 years of the study. We used encounter histories derived from DNA and the Jolly-Seber procedure in Program MARK

  12. Contrasting past and current numbers of bears visiting Yellowstone cutthroat trout streams

    Science.gov (United States)

    Haroldson, Mark A.; Schwartz, Charles C.; , JUSTIN E. TEISBERG; , Kerry A. Gunther; , JENNIFER K. FORTIN; , CHARLES T. ROBBINS

    2014-01-01

    Spawning cutthroat trout (Oncorhynchus clarkii bouvieri) were historically abundant within tributary streams of Yellowstone Lake within Yellowstone National Park and were a highly digestible source of energy and protein for Yellowstone’s grizzly bears (Ursus arctos) and black bears (U. americanus). The cutthroat trout population has subsequently declined since the introduction of non-native lake trout (Salvelinus namaycush), and in response to effects of drought and whirling disease (Myxobolus cerebralis). The trout population, duration of spawning runs, and indices of bear use of spawning streams had declined in some regions of the lake by 1997–2000. We initiated a 3-year study in 2007 to assess whether numbers of spawning fish, black bears, and grizzly bears within and alongside stream corridors had changed since 1997– 2000. We estimated numbers of grizzly bears and black bears by first compiling encounter histories of individual bears visiting 48 hair-snag sites along 35 historically fished streams.We analyzed DNA encounter histories with Pradel-recruitment and Jolly-Seber (POPAN) capture-mark-recapture models. When compared to 1997–2000, the current number of spawning cutthroat trout per stream and the number of streams with cutthroat trout has decreased. We estimated that 48 (95% CI¼42–56) male and 23 (95% CI¼21–27) female grizzly bears visited the historically fished tributary streams during our study. In any 1- year, 46 to 59 independent grizzly bears (8–10% of estimated Greater Yellowstone Ecosystem population) visited these streams. When compared with estimates from the 1997 to 2000 study and adjusted for equal effort, the number of grizzly bears using the stream corridors decreased by 63%. Additionally, the number of black bears decreased between 64% and 84%. We also document an increased proportion of bears of both species visiting front-country (i.e., near human development) streams. With the recovery of cutthroat trout, we suggest bears

  13. Using High-Resolution Models to Predict the Effects of Climate Change on Aquatic Ecosystems in the Crown of the Continent

    Science.gov (United States)

    Jones, L.; Muhlfeld, C.; Marshall, L. A.

    2013-12-01

    Climate trends and projections have prompted interest in assessing the thermal sensitivity of aquatic species. How species will adapt and respond to these changes is uncertain, however, climatic and hydrologic changes may shift species habitat distributions and physiological functions both spatially and temporally. This is particularly true for salmonids (e.g., trout, char, and salmon), which are cold-water species strongly influenced by changes in temperature, flow, and physical habitat conditions. Therefore, understanding how habitats are likely to change and how species may respond to changes in climatic conditions is critical for developing conservation and management strategies. The purpose of this study is to develop a high-resolution stream temperature model for the Crown of the Continent Ecosystem (CCE) to simulate potential climate change impacts on thermal regimes throughout the riverscape. A spatially explicit statistical regression model is coupled with high-resolution climate data such as air temperature, precipitation, solar radiation, baseflow and surface runoff. This empirically based model is used to predict daily stream temperatures under historic, current and forecasted climate conditions. The model is parameterized with empirical stream temperature data, which has been gathered from agencies across the region. The current database of empirical stream temperature data consists of over 800 sites throughout the CCE, which provide time series data to the model application. The biological integration and application of this model is on bull trout (Salvelinus confluentus) populations within the CCE. The model will be used to assess species vulnerabilities caused by spatial and temporal changes in stream temperature and hydrology. By evaluating the magnitude, timing and duration of climatic changes on the riverscape, we can more accurately assess potential vulnerabilities of critical life history traits, such as growth potential, spawning migrations

  14. Factors affecting biotic mercury concentrations and biomagnification through lake food webs in the Canadian high Arctic

    Energy Technology Data Exchange (ETDEWEB)

    Lescord, Gretchen L., E-mail: glescord@gmail.com [University of New Brunswick/Canadian Rivers Institute, 100 Tucker Park Rd, Saint John, NB E2L 4A6 (Canada); Kidd, Karen A. [University of New Brunswick/Canadian Rivers Institute, 100 Tucker Park Rd, Saint John, NB E2L 4A6 (Canada); Kirk, Jane L. [Environment Canada, Aquatic Contaminants Research Division, 867 Lakeshore Rd, Burlington, ON L7S 1A1 (Canada); O' Driscoll, Nelson J. [Acadia University, 15 University Ave, Wolfville, NS B4P 2R6 (Canada); Wang, Xiaowa; Muir, Derek C.G. [Environment Canada, Aquatic Contaminants Research Division, 867 Lakeshore Rd, Burlington, ON L7S 1A1 (Canada)

    2015-03-15

    In temperate regions of Canada, mercury (Hg) concentrations in biota and the magnitude of Hg biomagnification through food webs vary between neighboring lakes and are related to water chemistry variables and physical lake features. However, few studies have examined factors affecting the variable Hg concentrations in landlocked Arctic char (Salvelinus alpinus) or the biomagnification of Hg through their food webs. We estimated the food web structure of six high Arctic lakes near Resolute Bay, Nunavut, Canada, using stable carbon (δ{sup 13}C) and nitrogen (δ{sup 15}N) isotopes and measured Hg (total Hg (THg) in char, the only fish species, and methylmercury (MeHg) in chironomids and zooplankton) concentrations in biota collected in 2010 and 2011. Across lakes, δ{sup 13}C showed that benthic carbon (chironomids) was the dominant food source for char. Regression models of log Hg versus δ{sup 15}N (of char and benthic invertebrates) showed positive and significant slopes, indicting Hg biomagnification in all lakes, and higher slopes in some lakes than others. However, no principal components (PC) generated using all water chemistry data and physical characteristics of the lakes predicted the different slopes. The PC dominated by aqueous ions was a negative predictor of MeHg concentrations in chironomids, suggesting that water chemistry affects Hg bioavailability and MeHg concentrations in these lower-trophic-level organisms. Furthermore, regression intercepts were predicted by the PCs dominated by catchment area, aqueous ions, and MeHg. Weaker relationships were also found between THg in small char or MeHg in pelagic invertebrates and the PCs dominated by catchment area, and aqueous nitrate and MeHg. Results from these high Arctic lakes suggest that Hg biomagnification differs between systems and that their physical and chemical characteristics affect Hg concentrations in lower-trophic-level biota. - Highlights: • Mercury (Hg) in Arctic char and invertebrates

  15. Lake Michigan: Man's effects on native fish stocks and other biota

    Science.gov (United States)

    Wells, LaRue; McLain, Alberton L.

    1973-01-01

    Man's activities have caused great changes in Lake Michigan in the past 120 years. Although changes in water chemistry and lower biota have been generally modest (except locally), those in native fish stocks have been vast. Exploitation, exotic fish species, and eutrophication and other forms of pollution all have played a role in bringing about the changes (mostly declines in abundance) in fish populations. Exploitation resulted in a noticeable reduction in abundance of certain native species (especially whitefish) soon after the establishment of the commercial fishery in the 1840's. By the 1930's the sturgeon and the two largest deepwater ciscoes (Coregonus nigripinnis and C. johannae) became severely depleted. Other species- whitefish (Coregonus clupeaformis), lake trout (Salvelinus namaycush), and lake herring (C. artedii)- remained important commercially, but at a lower level of production than originally; greatly increased fishing effort and efficiency were required to maintain even these decreased catches. The catch of intermediate-size ciscoes held relatively stable, but again only through sharply increased fishing effort and efficiency. The earliest serious effects of exotic fish species on native fish stocks may have been during the 1930's, when smelt (Osmerus mordax), first became abundant. Powerful influences by exotics were not obvious, however, until the 1940's, when the sea lamprey's (Petromyzon marinus) predation on several species, particularly the lake trout, became critical. In the 1950's the sea lamprey was joined by the alewife (Alosa pseudoharengus), another exotic strongly deleterious to several native fish. The alewife apparently inhibited reproduction of deepwater ciscoes, yellow perch (Perca flavescens), deepwater sculpins (Myoxocephalus quadricornis), emerald shiners (Notropis atherinoides), and perhaps others (through competing with young, or feeding on them). At the same time, however, the alewife as a prolific forage fish has made

  16. Evaluate Bull Trout Movements in the Tucannon and Lower Snake Rivers, 2004 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Faler, Michael P. (US Fish and Wildlife Service, Idaho Fishery Resource Office, Ahsahka, ID); Mendel, Glen W.; Fulton, Carl (Washington Department of Fish and Wildlife, Fish Management Division, Dayton, WA)

    2005-11-01

    We sampled and released 313 bull trout (Salvelinus confluentus) from the Tucannon River in 2004. Passive Integrated Transponder (PIT) tags were inserted in 231 of these individuals, and we detected existing PIT tags in an additional 44 bull trout. Twenty-five of these were also surgically implanted with radio-tags, and we monitored the movements of these fish throughout the year. Ten bull trout that were radio-tagged in 2003 were known to survive and carry their tags through the spring of 2004. One of these fish outmigrated into the Snake River in the fall, and remained undetected until February, when it's tag was located near the confluence of Alkali Flat Creek and the Snake River. The remaining 9 fish spent the winter between Tucannon River miles 2.1 (Powers Road) and 36.0 (Tucannon Fish Hatchery). Seven of these fish retained their tags through the summer, and migrated to known spawning habitat prior to September 2004. During June and July, radio-tagged bull trout again exhibited a general upstream movement into the upper reaches of the Tucannon subbasin. As in past years, we observed some downstream movements of radio-tagged bull trout in mid to late September and throughout October, suggesting post spawning outmigrations. By late November and early December, radio tagged bull trout were relatively stationary, and were distributed from river mile 42 at Camp Wooten downstream to river mile 17, near the Highway 12 bridge. As in previous years, we did not collect data associated with objectives 2, 3, or 4 of this study, because we were unable to monitor migratory movement of radio-tagged bull trout into the vicinity of the hydropower dams on the main stem Snake River. Transmission tests of submerged Lotek model NTC-6-2 nano-tags in Lower Granite Pool showed that audible detection and individual tag identification was possible at depths of 20, 30, and 40 ft. We were able to maintain tag detection and code separation at all depths from both a boat and 200 ft

  17. Evaluation of Bull Trout Movements in the Tucannon and Lower Snake Rivers, 2002-2006 Project Completion Summary.

    Energy Technology Data Exchange (ETDEWEB)

    Faler, Michael P. [U.S. Fish and Wildlife Service; Mendel, Glen; Fulton, Carl [Washington Department of Fish and Wildlife

    2008-11-20

    The Columbia River Distinct Population Segment of bull trout (Salvelinus confluentus) was listed as threatened under the Endangered Species Act in 1998. One of the identified major threats to the species is fragmentation resulting from dams on over-wintering habitats of migratory subpopulations. A migratory subgroup in the Tucannon River appeared to utilize the Snake River reservoirs for adult rearing on a seasonal basis. As a result, a radio telemetry study was conducted on this subgroup from 2002-2006, to help meet Reasonable and Prudent Measures, and Conservation Recommendations associated with the lower Snake River dams in the FCRPS Biological Opinion, and to increase understanding of bull trout movements within the Tucannon River drainage. We sampled 1,109 bull trout in the Tucannon River; 124 of these were surgically implanted with radio tags and PIT tagged, and 681 were only PIT tagged. The remaining 304 fish were either recaptures, or released unmarked. Bull trout seasonal movements within the Tucannon River were similar to those described for other migratory bull trout populations. Bull trout migrated upstream in spring and early summer to the spawning areas in upper portions of the Tucannon River watershed. They quickly moved off the spawning areas in the fall, and either held or continued a slower migration downstream through the winter until early the following spring. During late fall and winter, bull trout were distributed in the lower half of the Tucannon River basin, down to and including the mainstem Snake River below Little Goose Dam. We were unable to adequately radio track bull trout in the Snake River and evaluate their movements or interactions with the federal hydroelectric dams for the following reasons: (1) none of our radio-tagged fish were detected attempting to pass a Snake River dam, (2) our radio tags had poor transmission capability at depths greater than 12.2 m, and (3) the sample size of fish that actually entered the Snake River

  18. Methow River Studies, Washington: abundance estimates from Beaver Creek and the Chewuch River screw trap, methodology testing in the Whitefish Island side channel, and survival and detection estimates from hatchery fish releases, 2013

    Science.gov (United States)

    Martens, Kyle D.; Fish, Teresa M.; Watson, Grace A.; Connolly, Patrick J.

    2014-01-01

    Salmon and steelhead populations have been severely depleted in the Columbia River from factors such as the presence of tributary dams, unscreened irrigation diversions, and habitat degradation from logging, mining, grazing, and others (Raymond, 1988). The U.S. Geological Survey (USGS) has been funded by the Bureau of Reclamation (Reclamation) to provide evaluation of on-going Reclamation funded efforts to recover Endangered Species Act (ESA) listed anadromous salmonid populations in the Methow River watershed, a watershed of the Columbia River in the Upper Columbia River Basin, in north-central Washington State (fig. 1). This monitoring and evaluation program was funded to document Reclamation’s effort to partially fulfill the 2008 Federal Columbia River Power System Biological Opinion (BiOp) (National Oceanographic and Atmospheric Administration, Fisheries Division 2003). This Biological Opinion includes Reasonable and Prudent Alternatives (RPA) to protect listed salmon and steelhead across their life cycle. Species of concern in the Methow River include Upper Columbia River (UCR) spring Chinook salmon (Oncorhynchus tshawytscha), UCR summer steelhead (O. mykiss), and bull trout (Salvelinus confluentus), which are all listed as threatened or endangered under the ESA. The work done by the USGS since 2004 has encompassed three phases of work. The first phase started in 2004 and continued through 2012. This first phase involved the evaluation of stream colonization and fish production in Beaver Creek following the modification of several water diversions (2000–2006) that were acting as barriers to upstream fish movement. Products to date from this work include: Ruttenburg (2007), Connolly and others (2008), Martens and Connolly (2008), Connolly (2010), Connolly and others (2010), Martens and Connolly (2010), Benjamin and others (2012), Romine and others (2013a), Weigel and others (2013a, 2013b, 2013c), and Martens and others (2014). The second phase, initiated in

  19. The physiology and toxicology of salmonid eggs and larvae in relation to water quality criteria

    International Nuclear Information System (INIS)

    The purpose of this review is to collate physiological knowledge on salmonid eggs and larvae in relation to water quality criteria. Salmonid genera reviewed include Coregonus, Thymallus, Salvelinus, Salmo, and Oncorhynchus spp. When physiological data for salmonids are lacking, the zebrafish and medaka models are included. The primary focus is on the underlying mechanisms involved in the hydro-mineral, thermal, and respiratory biology with an extended section on the xenobiotic toxicology of the early stages. Past and present data reveal that the eggs of salmonids are among the largest shed by any broadcast spawning teleost. Once ovulated, the physicochemical properties of the ovarian fluid provide temporary protection from external perturbations and maintain the eggs in good physiological condition until spawning. Following fertilisation and during early development the major structures protecting the embryo from poor water quality are the vitelline membrane, the enveloping layer and the chorion. The vitelline membrane is one of the least permeable membranes known, while the semi-permeable chorion provides both physical and chemical defense against metals, pathogens, and xenobiotic chemicals. In part these structures explain the lower sensitivity of the eggs to chemical imbalance compared to the larvae, however the lower metabolic rate and the chronology of gene expression and translational control suggest that developmental competence also plays a decisive role. In addition, maternal effect genes provide a defense potential until the mid-blastula transition. The transition between maternal effect genes and zygotic genes is a critical period for the embryo. The perivitelline fluids are an important trap for cations, but are also the major barrier to diffusion of gases and solutes. Acidic environmental pH interferes with acid-base and hydromineral balance but also increases the risk of aluminium and heavy metal intoxication. These risks are ameliorated somewhat by

  20. The physiology and toxicology of salmonid eggs and larvae in relation to water quality criteria

    Energy Technology Data Exchange (ETDEWEB)

    Finn, Roderick Nigel [Department of Biology, University of Bergen, Allegaten 41, N-5020 Bergen (Norway)]. E-mail: nigel.finn@bio.uib.no

    2007-03-30

    The purpose of this review is to collate physiological knowledge on salmonid eggs and larvae in relation to water quality criteria. Salmonid genera reviewed include Coregonus, Thymallus, Salvelinus, Salmo, and Oncorhynchus spp. When physiological data for salmonids are lacking, the zebrafish and medaka models are included. The primary focus is on the underlying mechanisms involved in the hydro-mineral, thermal, and respiratory biology with an extended section on the xenobiotic toxicology of the early stages. Past and present data reveal that the eggs of salmonids are among the largest shed by any broadcast spawning teleost. Once ovulated, the physicochemical properties of the ovarian fluid provide temporary protection from external perturbations and maintain the eggs in good physiological condition until spawning. Following fertilisation and during early development the major structures protecting the embryo from poor water quality are the vitelline membrane, the enveloping layer and the chorion. The vitelline membrane is one of the least permeable membranes known, while the semi-permeable chorion provides both physical and chemical defense against metals, pathogens, and xenobiotic chemicals. In part these structures explain the lower sensitivity of the eggs to chemical imbalance compared to the larvae, however the lower metabolic rate and the chronology of gene expression and translational control suggest that developmental competence also plays a decisive role. In addition, maternal effect genes provide a defense potential until the mid-blastula transition. The transition between maternal effect genes and zygotic genes is a critical period for the embryo. The perivitelline fluids are an important trap for cations, but are also the major barrier to diffusion of gases and solutes. Acidic environmental pH interferes with acid-base and hydromineral balance but also increases the risk of aluminium and heavy metal intoxication. These risks are ameliorated somewhat by

  1. Instream flow characterization of Upper Salmon River basin streams, central Idaho, 2005

    Science.gov (United States)

    Maret, Terry R.; Hortness, Jon E.; Ott, Douglas S.

    2006-01-01

    Anadromous fish populations in the Columbia River Basin have plummeted in the last 100 years. This severe decline led to Federal listing of Chinook salmon (Oncorhynchus tshawytscha) and steelhead trout (Oncorhynchus mykiss) stocks as endangered or threatened under the Endangered Species Act (ESA) in the 1990s. Historically, the upper Salmon River Basin (upstream of the confluence with the Pahsimeroi River) in Idaho provided migration corridors and significant habitat for these ESA-listed species, in addition to the ESA-listed bull trout (Salvelinus confluentus). Human development has modified the original streamflow conditions in many streams in the upper Salmon River Basin. Summer streamflow modifications resulting from irrigation practices, have directly affected quantity and quality of fish habitat and also have affected migration and (or) access to suitable spawning and rearing habitat for these fish. As a result of these ESA listings and Action 149 of the Federal Columbia River Power System Biological Opinion of 2000, the Bureau of Reclamation was tasked to conduct streamflow characterization studies in the upper Salmon River Basin to clearly define habitat requirements for effective species management and habitat restoration. These studies include collection of habitat and streamflow information for the Physical Habitat Simulation System (PHABSIM) model, a widely applied method to determine relations between habitat and discharge requirements for various fish species and life stages. Model simulation results can be used by resource managers to guide habitat restoration efforts by evaluating potential fish habitat and passage improvements by increasing or decreasing streamflow. In 2005, instream flow characterization studies were completed on Big Boulder, Challis, Bear, Mill, and Morgan Creeks. Continuous streamflow data were recorded upstream of all diversions on Big Boulder. Instantaneous measurements of discharge were also made at selected sites. In

  2. Kootenai River Fisheries Investigations; Rainbow and Bull Trout Recruitment, 2003-2004 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Walters, Jody P.

    2005-08-01

    Rainbow trout Oncorhynchus mykiss provide the most important sport fishery in the Kootenai River, Idaho, but densities and catch rates are low. Low recruitment is one possible factor limiting the rainbow trout population. Bull trout Salvelinus confluentus also exist in the Kootenai River, but little is known about this population. Research reported here addresses the following objectives for the Kootenai River, Idaho: identify sources of rainbow and bull trout recruitment, monitor the rainbow trout population size structure to evaluate regulation changes initiated in 2002, and identify factors potentially limiting rainbow trout recruitment. A screw trap was used to estimate juvenile redband and bull trout out-migration from the Callahan Creek drainage, and electrofishing was conducted to estimate summer densities of bull trout rearing in the Idaho portion of the drainage. An estimated 1,132 juvenile redband trout and 68 juvenile bull trout out-migrated from Callahan Creek to the Kootenai River from April 7 through July 15, 2003. Densities of bull trout {ge} age-1 in North and South Callahan creeks ranged from 1.6 to 7.7 fish/100m{sup 2} in August. Bull trout redd surveys were conducted in North and South Callahan creeks, Boulder Creek, and Myrtle Creek. Thirty-two bull trout redds were located in North Callahan Creek, while 10 redds were found in South Callahan Creek. No redds were found in the other two streams. Modeling of culverts in the Deep Creek drainage identified two as upstream migration barriers, preventing rainbow trout from reaching spawning and rearing habitat. Water temperature monitoring in Deep Creek identified two sites where maximum temperatures exceeded those suitable for rainbow trout. Boulder Creek produces the most rainbow trout recruits to the Kootenai River in Idaho upstream of Deep Creek, but may be below carrying capacity for rearing rainbow trout due to nutrient limitations. Monthly water samples indicate Boulder Creek is nutrient limited

  3. Coeur d'Alene Tribe Fisheries Program Research, Monitoring and Evaluation Plan; Implementation of Fisheries Enhancement Opportunities on the Coeur d'Alene Reservation, 1997-2002 Technical Report.

    Energy Technology Data Exchange (ETDEWEB)

    Vitale, Angelo; Lamb, Dave; Peters, Ronald

    2002-11-01

    Westslope cutthroat trout (Oncorhynchus clarki lewisi) and bull trout (Salvelinus confluentus) are currently of special concern regionally and are important to the culture and subsistence needs of the Coeur d'Alene Tribe. The mission of the Coeur d'Alene Tribe Fisheries Program is to restore and maintain these native trout and the habitats that sustain them in order to provide subsistence harvest and recreational fishing opportunities for the Reservation community. The adfluvial life history strategy exhibited by westslope cutthroat and bull trout in the Lake Coeur d'Alene subbasin makes these fish susceptible to habitat degradation and competition in both lake and stream environments. Degraded habitat in Lake Coeur d'Alene and its associated streams and the introduction of exotic species has lead to the decline of westslope cutthroat and listing of bull trout under the endangered species act (Peters et al. 1998). Despite the effects of habitat degradation, several streams on the Reservation still maintain populations of westslope cutthroat trout, albeit in a suppressed condition (Table 1). The results of several early studies looking at fish population status and habitat condition on the Reservation (Graves et al. 1990; Lillengreen et al. 1993, 1996) lead the Tribe to aggressively pursue funding for habitat restoration under the Northwest Power Planning Council's (NWPPC) resident fish substitution program. Through these efforts, habitat restoration needs were identified and projects were initiated. The Coeur d'Alene Tribe Fisheries Program is currently involved in implementing stream habitat restoration projects, reducing the transport of sediment from upland sources, and monitoring fish populations in four watersheds on the Coeur d'Alene Reservation (Figure 1). Restoration projects have included riparian plantings, addition of large woody debris to streams, and complete channel reconstruction to restore historical natural

  4. Hangman Restoration Project : Annual Report, August 1, 2001 - July 31, 2002.

    Energy Technology Data Exchange (ETDEWEB)

    Green, Gerald I.; Coeur D' Alene Tribe.

    2002-06-01

    The construction of hydroelectric facilities in the Columbia Basin resulted in the extirpation of anadromous fish stocks in Hangman Creek and its tributaries within the Coeur d'Alene Reservation. Thus, the Coeur d'Alene Indian Tribe was forced to rely more heavily on native fish stocks such as redband trout (Oncorhynchus mykiss garideini), westslope cutthroat trout (O. clarki lewisii) and bull trout (Salvelinus confluentus) as well as local wildlife populations. Additionally, the Tribe was forced to convert prime riparian habitat into agricultural lands to supply sustenance for their changed needs. Wildlife habitats within the portion of the Hangman Creek Watershed that lies within the Coeur d'Alene Indian Reservation have been degraded from a century of land management practices that include widespread conversion of native habitats to agricultural production and intensive silvicultural practices. Currently, wildlife and fish populations have been marginalized and water quality is significantly impaired. In the fall of 2000 the Coeur d'Alene Tribe Wildlife Program, in coordination with the Tribal Fisheries Program, submitted a proposal to begin addressing the degradations to functioning habitats within the Coeur d'Alene Reservation in the Hangman Watershed. That proposal led to the implementation of this project during BPA's FY2001 through FY2003 funding cycle. The project is intended to protect, restore and/or enhance priority riparian, wetland and upland areas within the headwaters of Hangman Creek and its tributaries in order to promote healthy self-sustaining fish and wildlife populations. A key goal of this project is the implementation of wildlife habitat protection efforts in a manner that also secures areas with the potential to provide stream and wetland habitats essential to native salmonid populations. This goal is critical in our efforts to address both resident fish and wildlife habitat needs in the Hangman Watershed. All

  5. Monitor and Protect Wigwam River Bull Trout for Koocanusa Reservoir; White River Bull Trout Enumeration Project Summary, Progress Report 2003.

    Energy Technology Data Exchange (ETDEWEB)

    Cope, R.

    2004-02-01

    This report summarizes the first year of a three-year bull trout (Salvelinus confluentus) enumeration project on the White River and is a co-operative initiative of the British Columbia Ministry of Water, Land, and Air Protection and Bonneville Power Administration. The White River has been identified as an important bull trout spawning tributary of the upper Kootenay River in southeastern British Columbia. The objective was to collect information on the returning adult spawning population to the White River through the use of a fish fence and traps, and to conduct redd surveys at the conclusion of spawning to provide an index of spawning escapement and distribution. The fence was installed on September 9th, 2003 and was operated continuously (i.e. no high-water or breaching events) until the fence was removed on October 9th, 2003. Estimation of the spawning population of White River bull trout was incomplete. This was due to a larger and more protracted out-migration than expected. As a result, the bull trout spawning population of the White River was estimated to be somewhere above 899 fish. In comparison, this represents approximately one third the population estimate of the 2003 Wigwam River bull trout spawning population. Based on redd index data, the number of bull trout per redd was over twice that of the Wigwam River or Skookumchuck Creek. This was expected as the index sites on the Wigwam River and Skookumchuck Creek cover the majority of the spawning area. This is not true on the White River. From previous redd counts, it is known that there are approximately twice as many redds in Blackfoot Creek as there are in the index site. Additionally, given the large size of the White River watershed and in particular, the large number of tributaries, there is a high likelihood that important bull trout spawning areas remain unidentified. Both floy tag and radio-telemetry data for the White River bull trout have identified extensive life history migrations

  6. 牙鲆胰岛素样生长因子结合蛋白IGFBP-1cDNA全长的克隆及表达分析%The full-length cDNA cloning and gene expression analysis of insulin-like growth factor binding protein 1 (IGFBP-1)in Japanese flounder ( Paralichthys olivaceus )

    Institute of Scientific and Technical Information of China (English)

    翟万营; 张俊玲; 施志仪; 李巍

    2012-01-01

    The full-length cDNA of insulin- like growth factor binding protein 1 gene (IGFBP-1) was obtained from the liver of Japanese flounder (Paralichthys olivaceus) using RACE method. The complete cDNA of P. olivaceus IGFBP-1 is 1 070 bp and its ORF includes 729 bp encoding 242 amino acid residues. The IGFBP-1 was highly homologous with IGFBP-1 gene in fish through phylogency analysis. The nucleotide sequence of IGFBP-1 from P. olivaceus shared 95% homology with that of Scophthalmus maximu, and the deduced amino acid analysis showed that the sequence similarities between P. olivaceus and 5. Maximu, Seriola quinqueradiata, Perca flavescens, Salvelinus alpines, Cyprinus carpio and Danio rerio, are 89% ,89% ,84% ,79% ,67% and 67% .respectively. Semi-quantitative RT-PCR results demonstrated that IGFBP-1 mRNA was detected in unfertilized egg, fertilized egg, embryonic and larval development, and various adult tissues. Moreover, real-time quantitative RT-PCR results showed that IGFBP-1 gene had the highest expression in adult liver and was expressed in a stage-specific manner during embryonic and larval development.%利用RACE-PCR技术,从牙鲆肝脏组织总RNA中克隆得到胰岛素样生长因子结合蛋白-1(insulin-like growth factor binding protein 1,IGFBP-1)基因的全长cDNA序列,该cDNA全长为1 070 bp,开放阅读框为729 bp,编码242个氨基酸.通过系统进化树分析,牙鲆IGFBP-1与鱼类IGFBP-1基因紧密聚为一支;通过同源性比对,牙鲆IGFBP-1基因的核苷酸序列与大菱鲆同源性最高,为95%,而其推导的氨基酸序列与其它鱼类如大菱鲆、五条(蛳)、黄金鲈、红点鲑、鲤和斑马鱼的同源性分别为89%、89%、84%、79%、67%和67%.半定量RT-PCR显示,牙鲆IGFBP-1 mRNA在未受精卵、受精卵、胚胎、仔鱼发育各阶段及成体各组织均被检测.荧光定量RT-PCR结果表明,牙鲆IGFBP-1基因在成鱼肝脏中表达量最高,且在胚胎和仔鱼发育期间具有明显的时期特异性.

  7. Implications of climate change for the fishes of the British Isles.

    Science.gov (United States)

    Graham, C T; Harrod, C

    2009-04-01

    temperatures are likely to favour cool-adapted (e.g. Perca fluviatilis) and warm-adapted freshwater fishes (e.g. roach Rutilus rutilus and other cyprinids) whose distribution and reproductive success may currently be constrained by temperature rather than by cold-adapted species (e.g. salmonids). Species that occur in Britain and Ireland that are at the edge of their distribution will be most affected, both negatively and positively. Populations of conservation importance (e.g.Salvelinus alpinus and Coregonus spp.) may decline irreversibly. However, changes in food-web dynamics and physiological adaptation, for example because of climate change, may obscure or alter predicted responses. The residual inertia in climate systems is such that even a complete cessation in emissions would still leave fishes exposed to continued climate change for at least half a century. Hence, regardless of the success or failure of programmes aimed at curbing climate change, major changes in fish communities can be expected over the next 50 years with a concomitant need to adapt management strategies accordingly. PMID:20735625

  8. Evaluate Bull Trout Movements in the Tucannon and Lower Snake Rivers, 2002-2003 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Faler, Michael P. (US Fish and Wildlife Service, Idaho Fishery Resource Office, Ahsahka, ID); Mendel, Glen W.; Fulton, Carl (Washington Department of Fish and Wildlife, Fish Management Division, Dayton, WA)

    2004-04-01

    We collected 279 adult bull trout (Salvelinus confluentus) in the Tucannon River during the Spring and Fall of 2003. Passive Integrated Transponder (PIT) tags were inserted in 191 of them, and we detected existing PIT tags in an additional 31bull trout. Thirty five of these were also surgically implanted with radio-tags, and we monitored the movements of these fish throughout the year. Fourteen radio-tags were recovered shortly after tagging, and as a result, 21 remained in the river through December 31, 2003. Four bull trout that were radio-tagged in spring 2002 were known to survive and carry their tags through the spring and/or summer of 2003. One of these fish spent the winter near river mile (RM) 13.0; the other 3 over-wintered in the vicinity of the Tucannon Hatchery between RM 34 and 36. Twenty-one radio tags from bull trout tagged in 2002 were recovered during the spring and summer, 2003. These tags became stationary the winter of 2002/2003, and were recovered between RM 11 and 55. We were unable to recover the remaining 15 tags from 2002. During the month of July, radio-tagged bull trout exhibited a general upstream movement into the upper reaches of the Tucannon subbasin. We observed some downstream movements of radio-tagged bull trout in mid to late September and throughout October. By late November and early December, radio tagged bull trout were relatively stationary, and were distributed from the headwaters downstream to river mile 6.4, near Lower Monumental Pool. As in 2002, we did not conduct work associated with objectives 2, 3, or 4 of this study, because we were unable to monitor migratory movement of radio-tagged bull trout into the Federal hydropower system on the mainstem Snake River. Transmission tests of submerged ATS model F1830 radio-tags in Lower Granite Pool showed that audible detection and individual tag identification was possible at depths of 20 and 30 ft. Tests were conducted using an ATS R-4000 Receiver equipped with an &apos

  9. Kokanee Stocking and Monitoring, Flathead Lake, 1993-1994 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Deleray, Mark (Montana Department of Fish, Wildlife and Parks, Kalispell, MT); Fredenberg, Wade (US Fish and Wildlife Service, Bozeman, MT); Hansen, Barry (Confederated Salish and Kootenai Tribes of the Flathead Nation, Pablo, MT)

    1995-07-01

    One mitigation goal of the Hungry Horse Dam fisheries mitigation program, funded by the Bonneville Power Administration, is to replace lost production of 100,000 adult kokanee in Flathead Lake. The mitigation program calls for a five-year test to determine if kokanee can be reestablished in Flathead Lake. The test consists. of annual stocking of one million hatchery-raised yearling kokanee. There are three benchmarks for judging the success of the kokanee reintroduction effort: (1) Post-stocking survival of 30 percent of planted kokanee one year after stocking; (2) Yearling to adult survival of 10 percent (100,000 adult salmon); (3) Annual kokanee harvest of 50,000 or more fish per year by 1998, with an average length of 11 inches or longer for harvested fish, and fishing pressure of 100,000 angler hours or more. Kokanee were the primary sport fish species in the Flathead Lake fishery in the early 1900s, and up until the late 1980s when the population rapidly declined in numbers and then disappeared. Factors identified which influenced the decline of kokanee are the introduction of opossum shrimp (Mysis relicta), hydroelectric operations, overharvest through angling, and competition and/or predation by lake trout (Salvelinus namaycush) and lake whitefish (Coregonur clupeaformis). The purpose of this report was to summarize the stocking program and present monitoring results from the 1993 and 1994 field seasons. In June 1993, roughly 210,000 yearling kokanee were stocked into two bays on the east shore of Flathead Lake. Following stocking, we observed a high incidence of stocked kokanee in stomach samples from lake trout captured in areas adjacent to the stocking sites and a high percentage of captured lake trout containing kokanee. Subsequent monitoring concluded that excessive lake trout predation precluded significant survival of kokanee stocked in 1993. In June 1994, over 802,000 kokanee were stocked into Big Arm Bay. The combination of near optimum water

  10. Kootenay Lake Fertilization Experiment, Year 15 (North Arm) and Year 3 (South Arm) (2006) Report

    Energy Technology Data Exchange (ETDEWEB)

    Schindler, E.U.; Sebastian, D.; Andrusak, G.F. [Fish and Wildlife Science and Allocation, Ministry of Environment, Province of British Columbia

    2009-07-01

    This report summarizes results from the fifteenth year (2006) of nutrient additions to the North Arm of Kootenay Lake and three years of nutrient additions to the South Arm. Experimental fertilization of the lake has been conducted using an adaptive management approach in an effort to restore lake productivity lost as a result of nutrient uptake in upstream reservoirs. The primary objective of the experiment is to restore kokanee (Oncorhynchus nerka) populations, which are the main food source for Gerrard rainbow trout (Oncorhynchus mykiss) and bull trout (Salvelinus confluentus). The quantity of agricultural grade liquid fertilizer (10-34-0, ammonium polyphosphate and 28-0-0, urea ammonium nitrate) added to the North Arm in 2006 was 44.7 tonnes of P and 248.4 tonnes of N. The total fertilizer load added to the South Arm was 257 tonnes of nitrogen; no P was added. Kootenay Lake has an area of 395 km{sup 2}, a maximum depth of 150 m, a mean depth of 94 m, and a water renewal time of approximately two years. Kootenay Lake is a monomictic lake, generally mixing from late fall to early spring and stratifying during the summer. Surface water temperatures generally exceed 20 C for only a few weeks in July. Results of oxygen profiles were similar to previous years with the lake being well oxygenated from the surface to the bottom depths at all stations. Similar to past years, Secchi disc measurements at all stations in 2006 indicate a typical seasonal pattern of decreasing depths associated with the spring phytoplankton bloom, followed by increasing depths as the bloom gradually decreases by the late summer and fall. Total phosphorus (TP) ranged from 2-7 {micro}g/L and tended to decrease as summer advanced. Over the sampling season dissolved inorganic nitrogen (DIN) concentrations decreased, with the decline corresponding to nitrate (the dominant component of DIN) being utilized by phytoplankton during summer stratification. Owing to the importance of epilimnetic nitrate

  11. Assessment of Salmonids and Their Habitat Conditions in the Walla Walla River Basin within Washington, Annual Report 2002-2003.

    Energy Technology Data Exchange (ETDEWEB)

    Mendel, Glen; Trump, Jeremy; Gembala, Mike

    2003-09-01

    This study began in 1998 to assess salmonid distribution, relative abundance, genetics, and the condition of salmonid habitats in the Walla Walla River basin. Stream flows in the Walla Walla Basin continue to show a general trend that begins with a sharp decline in discharge in late June, followed by low summer flows and then an increase in discharge in fall and winter. Manual stream flow measurements at Pepper bridge showed an increase in 2002 of 110-185% from July-September, over flows from 2001. This increase is apparently associated with a 2000 settlement agreement between the U.S. Fish and Wildlife Service (USFWS) and the irrigation districts to leave minimum flows in the river. Stream temperatures in the Walla Walla basin were similar to those in 2001. Upper montane tributaries maintained maximum summer temperatures below 65 F, while sites in mid and lower Touchet and Walla Walla rivers frequently had daily maximum temperatures well above 68 F (high enough to inhibit migration in adult and juvenile salmonids, and to sharply reduce survival of their embryos and fry). These high temperatures are possibly the most critical physiological barrier to salmonids in the Walla Walla basin, but other factors (available water, turbidity or sediment deposition, cover, lack of pools, etc.) also play a part in salmonid survival, migration, and breeding success. The increased flows in the Walla Walla, due to the 2000 settlement agreement, have not shown consistent improvements to stream temperatures. Rainbow/steelhead (Oncorhynchus mykiss) trout represent the most common salmonid in the basin. Densities of Rainbow/steelhead in the Walla Walla River from the Washington/Oregon stateline to Mojonnier Rd. dropped slightly from 2001, but are still considerably higher than before the 2000 settlement agreement. Other salmonids including; bull trout (Salvelinus confluentus), chinook salmon (Oncorhynchus tshawytscha), mountain whitefish (Prosopium williamsoni), and brown trout (Salmo

  12. Implementation of Fisheries Enhancement Opportunities on the Coeur d'Alene Reservation; Coeur d'Alene Tribe Fish, Water, and Wildlife Program, REVISED 2002 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Vitale, Angelo; Lamb, Dave; Scott, Jason

    2004-04-01

    Historically, the Coeur d'Alene Indian Tribe depended on runs of anadromous salmon and steelhead along the Spokane River and Hangman Creek, as well as resident and adfluvial forms of trout and char in Coeur d'Alene Lake, for survival. Dams constructed in the early 1900s on the Spokane River in the City of Spokane and at Little Falls (further downstream) were the first dams that initially cut-off the anadromous fish runs from the Coeur d'Alene Tribe. These fisheries were further removed by the construction of Chief Joseph and Grand Coulee Dams on the Columbia River. Together, these actions forced the Tribe to rely solely on the resident fish resources of Coeur d'Alene Lake (Staff Communication). The Coeur d'Alene Tribe is estimated to have historically harvested around 42,000 westslope cutthroat trout (Oncorhynchus clarki) per year (Scholz et al. 1985). In 1967, Mallet (1969) reported that 3,329 cutthroat were harvested from the St. Joe River, and a catch of 887 was reported from Coeur d'Alene Lake. This catch is far less than the 42,000 fish per year the tribe harvested historically. Today, only limited opportunities exist to harvest cutthroat trout in the Coeur d'Alene Basin. The declines in native salmonid fish populations, particularly cutthroat and bull trout (Salvelinus confluentus), in the Coeur d'Alene basin have been the focus of study by the Coeur d' Alene Tribe's Fisheries and Water Resources programs since 1990. It appears that there are a number of factors contributing to the decline of resident salmonid stocks within Coeur d'Alene Lake and its tributaries (Ellis 1932; Oien 1957; Mallet 1969; Scholz et. al. 1985, Lillengreen et. al. 1993). These factors include: construction of Post Falls Dam in 1906; major changes in land cover types, agricultural activities and introduction of exotic fish species. Over 100 years of mining activities in the Coeur d'Alene River drainage have had devastating

  13. Implementation of Fisheries Enhancement Opportunities on the Coeur d'Alene Reservation, 2002 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Vitale, Angelo, Lamb, Dave; Scott, Jason

    2003-12-01

    Historically, the Coeur d'Alene Indian Tribe depended on runs of anadromous salmon and steelhead along the Spokane River and Hangman Creek, as well as resident and adfluvial forms of trout and char in Coeur d'Alene Lake, for survival. Dams constructed in the early 1900s on the Spokane River in the City of Spokane and at Little Falls (further downstream) were the first dams that initially cut-off the anadromous fish runs from the Coeur d'Alene Tribe. These fisheries were further removed by the construction of Chief Joseph and Grand Coulee Dams on the Columbia River. Together, these actions forced the Tribe to rely solely on the resident fish resources of Coeur d'Alene Lake (Staff Communication). The Coeur d'Alene Tribe is estimated to have historically harvested around 42,000 westslope cutthroat trout (Oncorhynchus clarki) per year (Scholz et al. 1985). In 1967, Mallet (1969) reported that 3,329 cutthroat were harvested from the St. Joe River, and a catch of 887 was reported from Coeur d'Alene Lake. This catch is far less than the 42,000 fish per year the tribe harvested historically. Today, only limited opportunities exist to harvest cutthroat trout in the Coeur d'Alene Basin. The declines in native salmonid fish populations, particularly cutthroat and bull trout (Salvelinus confluentus), in the Coeur d'Alene basin have been the focus of study by the Coeur d' Alene Tribe's Fisheries and Water Resources programs since 1990. It appears that there are a number of factors contributing to the decline of resident salmonid stocks within Coeur d'Alene Lake and its tributaries (Ellis 1932; Oien 1957; Mallet 1969; Scholz et. al. 1985, Lillengreen et. al. 1993). These factors include: construction of Post Falls Dam in 1906; major changes in land cover types, agricultural activities and introduction of exotic fish species. Over 100 years of mining activities in the Coeur d'Alene River drainage have had devastating

  14. Kootenay Lake Fertilization Experiment, Year 15 (North Arm) and Year 3 (South Arm) (2006) Report

    Energy Technology Data Exchange (ETDEWEB)

    Schindler, E.U.; Sebastian, D.; Andrusak, G.F. [Fish and Wildlife Science and Allocation, Ministry of Environment, Province of British Columbia

    2009-07-01

    This report summarizes results from the fifteenth year (2006) of nutrient additions to the North Arm of Kootenay Lake and three years of nutrient additions to the South Arm. Experimental fertilization of the lake has been conducted using an adaptive management approach in an effort to restore lake productivity lost as a result of nutrient uptake in upstream reservoirs. The primary objective of the experiment is to restore kokanee (Oncorhynchus nerka) populations, which are the main food source for Gerrard rainbow trout (Oncorhynchus mykiss) and bull trout (Salvelinus confluentus). The quantity of agricultural grade liquid fertilizer (10-34-0, ammonium polyphosphate and 28-0-0, urea ammonium nitrate) added to the North Arm in 2006 was 44.7 tonnes of P and 248.4 tonnes of N. The total fertilizer load added to the South Arm was 257 tonnes of nitrogen; no P was added. Kootenay Lake has an area of 395 km{sup 2}, a maximum depth of 150 m, a mean depth of 94 m, and a water renewal time of approximately two years. Kootenay Lake is a monomictic lake, generally mixing from late fall to early spring and stratifying during the summer. Surface water temperatures generally exceed 20 C for only a few weeks in July. Results of oxygen profiles were similar to previous years with the lake being well oxygenated from the surface to the bottom depths at all stations. Similar to past years, Secchi disc measurements at all stations in 2006 indicate a typical seasonal pattern of decreasing depths associated with the spring phytoplankton bloom, followed by increasing depths as the bloom gradually decreases by the late summer and fall. Total phosphorus (TP) ranged from 2-7 {micro}g/L and tended to decrease as summer advanced. Over the sampling season dissolved inorganic nitrogen (DIN) concentrations decreased, with the decline corresponding to nitrate (the dominant component of DIN) being utilized by phytoplankton during summer stratification. Owing to the importance of epilimnetic nitrate

  15. Coeur d'Alene Tribe Fish and Wildlife Program Habitat Protection Plan; Implementation of Fisheries Enhancement Opportunities on the Coeur d'Alene Reservation, 1997-2002 Technical Report.

    Energy Technology Data Exchange (ETDEWEB)

    Vitale, Angelo; Roberts, Frank; Peters, Ronald

    2002-06-01

    Throughout the last century, the cumulative effects of anthropogenic disturbances have caused drastic watershed level landscape changes throughout the Reservation and surrounding areas (Coeur d'Alene Tribe 1998). Changes include stream channelization, wetland draining, forest and palouse prairie conversion for agricultural use, high road density, elimination of old growth timber stands, and denuding riparian communities. The significance of these changes is manifested in the degradation of habitats supporting native flora and fauna. Consequently, populations of native fish, wildlife, and plants, which the Tribe relies on as subsistence resources, have declined or in some instances been extirpated (Apperson et al. 1988; Coeur d'Alene Tribe 1998; Lillengreen et al. 1996; Lillengreen et al. 1993; Gerry Green Coeur d'Alene Tribe wildlife Biologist, personal communication 2002). For example, bull trout (Salvelinus confluentus) are not present at detectable levels in Reservation tributaries, westslope cutthroat trout (Oncorhynchus clarki lewisi) are not present in numbers commensurate with maintaining harvestable fisheries (Lillengreen et al. 1993, 1996), and the Sharp-tailed grouse (Tympanuchus phasianellus) are not present at detectable levels on the Reservation (Gerry Green, Coeur d'Alene Tribe wildlife biologist, personal communication). The Coeur d'Alene Tribe added Fisheries and Wildlife Programs to their Natural Resources Department to address these losses and protect important cultural, and subsistence resources for future generations. The Tribal Council adopted by Resolution 89(94), the following mission statement for the Fisheries Program: 'restore, protect, expand and re-establish fish populations to sustainable levels to provide harvest opportunities'. This mission statement, focused on fisheries restoration and rehabilitation, is a response to native fish population declines throughout the Tribe's aboriginal territory