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Sample records for brown trout populations

  1. Some Direct Gillnet Selectivity Tests for Brown Trout Populations

    OpenAIRE

    O Grady, M. F.

    1981-01-01

    Direct gillnet selectivity tests for introduced brown trout populations in three Irish lakes are outlined. The net gangs and netting procedure utilised are described. Data indicates that the gear used was capable of capturing a random cross section of a trout stock in the length frequency range 19.8 to 47.7 centimetres.

  2. 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.

  3. Admixture analysis of stocked brown trout populations using mapped microsatellite DNA markers: indigenous trout persist in introgressed populations

    DEFF Research Database (Denmark)

    Hansen, Michael Møller; Mensberg, Karen-Lise Dons

    2009-01-01

    , but resolution is low if genetic differentiation is weak. Here, we analyse stocked brown trout populations represented by historical (1943-1956) and contemporary (2000s) samples, where genetic differentiation between wild populations and stocked trout is weak (pair-wise F-ST of 0.047 and 0.053). By...

  4. Regulation of an unexploited brown trout population in Spruce Creek, Pennsylvania

    Science.gov (United States)

    Carline, R.F.

    2006-01-01

    The purpose of this paper is to describe the annual variations in the density of an unexploited population of lotic brown trout Salmo trutta that has been censused annually for 19 years and to explore the importance of density-independent and density-dependent processes in regulating population size. Brown trout density and indices of stream discharge and water temperature were related to annual variations in natural mortality, recruitment, and growth. Annual mortality of age-1 and older (age-1+) brown trout ranged from 0.30 to 0.75 and was best explained by discharge during spring and by brown trout density. Recruitment to age 1 varied fivefold. Density of age-1 brown trout was inversely related to spawner density and positively related to discharge during the fall spawning period. The median length of age-1 brown trout was positively related to discharge during summer and fall. Relative weight was inversely related to the density of age-2+ brown trout. The interactive effects of discharge and brown trout density accounted for most of the annual variation in mortality, recruitment, and growth during the first year of life. Annual trends in the abundance of age-1+ brown trout were largely dictated by natural mortality. ?? Copyright by the American Fisheries Society 2006.

  5. Influence of small hydropower plants on brown trout (Salmo trutta L. population in Mislinja River

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    Blaž Cokan

    2013-12-01

    Full Text Available The brown trout (Salmo trutta L. in the Mislinja River has been endangered for years because of small hydroelectric power plants. To find out how they are affecting the population of the brown trout in the Mislinja River, we conducted a sampling of the brown trout, using a generating set. We measured the length and weight of all caught specimens and analysed the obtained data. The results are presented in this paper, e.g., biomass, estimations of abundance, average weight, average length and number of captured brown trout. We discovered that the population of the brown trout has decreased in all the sections where water has been taken away for small hydroelectric power plants.

  6. Influence of small hydropower plants on brown trout (Salmo trutta L.) population in Mislinja River

    OpenAIRE

    Blaž Cokan; Blaž Repe

    2013-01-01

    The brown trout (Salmo trutta L.) in the Mislinja River has been endangered for years because of small hydroelectric power plants. To find out how they are affecting the population of the brown trout in the Mislinja River, we conducted a sampling of the brown trout, using a generating set. We measured the length and weight of all caught specimens and analysed the obtained data. The results are presented in this paper, e.g., biomass, estimations of abundance, average weight, average length and...

  7. Founder effects and genetic population structure of brown trout (Salmo trutta) in a Danish river system

    DEFF Research Database (Denmark)

    Hansen, Michael Møller; Mensberg, Karen-Lise Dons

    1996-01-01

    The influence of founder effects on the genetic population structure of brown trout (Salmo trutta) was studied in a small Danish river system. Samples of trout from seven locations were analysed by allozyme electrophoresis and mitochondrial DNA restriction fragment length polymorphism analysis. For...

  8. Admixture analysis of stocked brown trout populations using mapped microsatellite DNA markers: indigenous trout persist in introgressed populations

    OpenAIRE

    Hansen, Michael M; Mensberg, Karen-Lise D.

    2009-01-01

    Admixture between wild and captive populations is an increasing concern in conservation biology. Understanding the extent of admixture and the processes involved requires identification of admixed and non-admixed individuals. This can be achieved by statistical methods employing Bayesian clustering, but resolution is low if genetic differentiation is weak. Here, we analyse stocked brown trout populations represented by historical (1943–1956) and contemporary (2000s) samples, where genetic dif...

  9. Genetic structure and demographic history of brown trout ( Salmo trutta ) populations from the southern Balkans

    DEFF Research Database (Denmark)

    Apostolidis, A.P.; Madeira, M.J.; Hansen, Michael Møller;

    2008-01-01

    1. The present study was designed to characterize the genetic structure of brown trout (Salmo trutta) populations from the southern Balkans and to assess the spread of non-native strains and their introgression into native trout gene pools. We analysed polymorphism at nine microsatellite loci......, analyses of the stocked populations revealed that the genetic integrity of the local populations had been substantially changed, and the populations must be characterized as hybrid swarms. The pattern of population differentiation observed at microsatellites contrasted to that depicted previously by mt...... compromised. Therefore, appropriate management and conservation strategies should be developed urgently in order to protect the subspecific biodiversity and to reverse currently negative trends....

  10. Incidence of physical injury of mature male parr in a natural population of brown trout

    DEFF Research Database (Denmark)

    Broberg, M.M.; Eg Nielsen, Einar; Dieperink, C.

    2000-01-01

    In a brown trout Salmo trutta population, there was a much higher frequency of injuries among mature male parr than among immature or female parr. The quantitative data are discussed in relation to spawning success and overall fitness. (C) 2000 The Fisheries Society of the British Isles....

  11. Identifying footprints of selection in stocked brown trout populations: a spatio-temporal approach

    DEFF Research Database (Denmark)

    Hansen, Michael Møller; Meier, Kristian; Mensberg, Karen-Lise Dons

    2010-01-01

    Studies of interactions between farmed and wild salmonid fishes have suggested reduced fitness of farmed strains in the wild, but evidence for selection at the genic level is lacking. We studied three brown trout populations in Denmark which have been significantly admixed with stocked hatchery...

  12. Long-term species balance in sympatric populations: implications for Atlantic salmon and brown trout

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    Jose Luis Horreo

    2014-09-01

    Full Text Available The factors determining regional adaptation in salmonids are still unclear, but it is known that changes in their habitat imply changes in their population structure. In this preliminary study we integrate habitat data, molecular analyses (from both nuclear microsatellite and mitochondrial loci and life-history traits (measured on archaeological vertebrae and modern scales of two sympatric salmonid species: Atlantic salmon and brown trout. We propose that water temperature and geological characteristics changed the biogeographic patterns of these species through asymmetric migration and different (but complementary population growth rates. As a consequence, differences in a life-history trait (mean number of years at sea and population sizes were detected between regions, suggesting a process of substitution of Atlantic salmon by brown trout.

  13. Long-term species balance in sympatric populations: implications for Atlantic salmon and brown trout

    OpenAIRE

    Horreo, Jose Luis; Turrero, Pablo; Perez, Juliana; García-Vázquez, Eva

    2014-01-01

    The factors determining regional adaptation in salmonids are still unclear, but it is known that changes in their habitat imply changes in their population structure. In this preliminary study we integrate habitat data, molecular analyses (from both nuclear microsatellite and mitochondrial loci) and life-history traits (measured on archaeological vertebrae and modern scales) of two sympatric salmonid species: Atlantic salmon and brown trout. We propose that water temperature and geological ch...

  14. The effects of Medieval dams on genetic divergence and demographic history in brown trout populations

    Science.gov (United States)

    2014-01-01

    Background Habitat fragmentation has accelerated within the last century, but may have been ongoing over longer time scales. We analyzed the timing and genetic consequences of fragmentation in two isolated lake-dwelling brown trout populations. They are from the same river system (the Gudenå River, Denmark) and have been isolated from downstream anadromous trout by dams established ca. 600–800 years ago. For reference, we included ten other anadromous populations and two hatchery strains. Based on analysis of 44 microsatellite loci we investigated if the lake populations have been naturally genetically differentiated from anadromous trout for thousands of years, or have diverged recently due to the establishment of dams. Results Divergence time estimates were based on 1) Approximate Bayesian Computation and 2) a coalescent-based isolation-with-gene-flow model. Both methods suggested divergence times ca. 600–800 years bp, providing strong evidence for establishment of dams in the Medieval as the factor causing divergence. Bayesian cluster analysis showed influence of stocked trout in several reference populations, but not in the focal lake and anadromous populations. Estimates of effective population size using a linkage disequilibrium method ranged from 244 to > 1,000 in all but one anadromous population, but were lower (153 and 252) in the lake populations. Conclusions We show that genetic divergence of lake-dwelling trout in two Danish lakes reflects establishment of water mills and impassable dams ca. 600–800 years ago rather than a natural genetic population structure. Although effective population sizes of the two lake populations are not critically low they may ultimately limit response to selection and thereby future adaptation. Our results demonstrate that populations may have been affected by anthropogenic disturbance over longer time scales than normally assumed. PMID:24903056

  15. Estimating the long-term effects of stocking domesticated trout into wild brown trout ( Salmo trutta ) populations : an approach using microsatellite DNA analysis of historical and contemporary samples

    DEFF Research Database (Denmark)

    Hansen, Michael Møller

    2002-01-01

    Indigenous salmonid fish gene pools are affected by domesticated conspecifics, derived from aquaculture escapes and deliberate releases. Variability was examined at nine microsatellite loci in order to assess the long-term impact of stocking domesticated trout in two brown trout populations. The ...... of stocked trout, could explain the observed introgression. Few nonadmixed individuals remained in the introgressed population, and I discuss how individual admixture analysis can be used to identify and conserve nonintrogressed remains of the population....... study was based on analysis of two historical samples (194556), represented by old scale collections, and seven contemporary samples (1986-2000). In one population historical and contemporary samples were remarkably genetically similar despite more than a decade of intense stocking. Estimation of...... admixture proportions showed a small genetic contribution from domesticated trout (approximately 6%), and individual admixture analysis demonstrated a majority of nonadmixed individuals. The expected genetic contribution by domesticated trout was 64%, assessed from the number of stocked trout and assuming...

  16. Genetic Background and Population Genetics of Hungarian Brown Trout Populations Using PCR-RFLP and Microsatellite Markers

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    Ágnes Ősz

    2015-12-01

    4 University of West Hungary, Mosonmagyaróvár Vár 2., 9200 Mosonmagyaróvár, Hungary Based on the analyses of the mitochondrial DNA of several European brown trout populations, five evolutionary lineages of brown trout were indentified (Atlantic, Danubian, Mediterranean, Adriatic, Marble. The species is bred primarily for stock enhancement of natural waters, however the most hatchery-maintained broodstocks originate from the Atlantic lineage. Due to the hydrogeography of Hungary our stocks should theoretically belong to the Danubian lineage; however, this has not been investigated earlier by genetic studies. For our genetic analysis, 702 fin clips were collected from two brown trout broodstocks (Lillafüred and Szilvásvárad as well as populations of natural streams (Bán, Jósva, Kemence, Apátkút, Bittva and Kölöntés in Hungary. Sequencing of the control region in mitochondrial DNA, three PCR-RFLP (mitochondrial DNA control region, lactate dehydrogenase and somatolactin genes and five microsatellite markers were used to distinguish between Danubian and Atlantic lineages of brown trout. The proportion of the mitochondrial haplotype of the Danubian lineage was low, with the exception of the Apátkúti, Kölöntés streams and Szilvásvárad broodstock. Analyses of nuclear PCR-RFLP and microsatellites markers showed various distributions of alleles characteristic of the Atlantic or Danubian lineages, although the Atlantic genotype has dominated in all population. In case of the analyses of microsatellites the polymorphism varied greatly at all locations. In addition we found several alleles that were not described earlier in other populations. Those alleles probably would be typical of Hungarian brown trout populations. Overall the populations were effectively in Hardy-Weinberg equilibrium for both PCR-RFLP and microsatellite markers. The remarkably high proportion of allochthonous Atlantic alleles in the analyzed sites is a clear indicator of the import

  17. Genetic restoration of a stocked brown trout Salmo trutta population using microsatellite DNA analysis of historical and contemporary samples

    DEFF Research Database (Denmark)

    Hansen, Michael Møller; Bekkevold, Dorte; Jensen, L.F.;

    2006-01-01

    1. Gene flow from domesticated to wild populations is a major threat to wild salmonid fish. However, few studies have addressed how populations could be restored after admixture has occurred. We analysed the prospects for restoring the previously intensively stocked brown trout population of the...

  18. Experimental tests for heritable morphological color plasticity in non-native brown trout (Salmo trutta populations.

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    Peter A H Westley

    Full Text Available The success of invasive species is frequently attributed to phenotypic plasticity, which facilitates persistence in novel environments. Here we report on experimental tests to determine whether the intensity of cryptic coloration patterns in a global invader (brown trout, Salmo trutta was primarily the result of plasticity or heritable variation. Juvenile F1 offspring were created through experimental crosses of wild-caught parents and reared for 30 days in the laboratory in a split-brood design on either light or dark-colored gravel substrate. Skin and fin coloration quantified with digital photography and image analysis indicated strong plastic effects in response to substrate color; individuals reared on dark substrate had both darker melanin-based skin color and carotenoid-based fin colors than other members of their population reared on light substrate. Slopes of skin and fin color reaction norms were parallel between environments, which is not consistent with heritable population-level plasticity to substrate color. Similarly, we observed weak differences in population-level color within an environment, again suggesting little genetic control on the intensity of skin and fin colors. Taken as whole, our results are consistent with the hypothesis that phenotypic plasticity may have facilitated the success of brown trout invasions and suggests that plasticity is the most likely explanation for the variation in color intensity observed among these populations in nature.

  19. 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

  20. The problem of sampling families rather than populations: Relatedness among individuals in samples of juvenile brown trout Salmo trutta L

    DEFF Research Database (Denmark)

    Hansen, Michael Møller; Eg Nielsen, Einar; Mensberg, Karen-Lise Dons

    1997-01-01

    In species exhibiting a nonrandom distribution of closely related individuals, sampling of a few families may lead to biased estimates of allele frequencies in populations. This problem was studied in two brown trout populations, based on analysis of mtDNA and microsatellites. In both samples mtDNA...... haplotype frequencies differed significantly between age classes, and in one sample 17 out of 18 individuals less than 1 year of age shared one particular mtDNA haplotype. Estimates of relatedness showed that these individuals most likely represented only three full-sib families. Older trout exhibiting the...

  1. Human mining activity across the ages determines the genetic structure of modern brown trout (Salmo trutta L.) populations.

    Science.gov (United States)

    Paris, Josephine R; King, R Andrew; Stevens, Jamie R

    2015-07-01

    Humans have exploited the earth's metal resources for thousands of years leaving behind a legacy of toxic metal contamination and poor water quality. The southwest of England provides a well-defined example, with a rich history of metal mining dating to the Bronze Age. Mine water washout continues to negatively impact water quality across the region where brown trout (Salmo trutta L.) populations exist in both metal-impacted and relatively clean rivers. We used microsatellites to assess the genetic impact of mining practices on trout populations in this region. Our analyses demonstrated that metal-impacted trout populations have low genetic diversity and have experienced severe population declines. Metal-river trout populations are genetically distinct from clean-river populations, and also from one another, despite being geographically proximate. Using approximate Bayesian computation (ABC), we dated the origins of these genetic patterns to periods of intensive mining activity. The historical split of contemporary metal-impacted populations from clean-river fish dated to the Medieval period. Moreover, we observed two distinct genetic populations of trout within a single catchment and dated their divergence to the Industrial Revolution. Our investigation thus provides an evaluation of contemporary population genetics in showing how human-altered landscapes can change the genetic makeup of a species. PMID:26136823

  2. Sixty years of anthropogenic pressure: a spatio-temporal genetic analysis of brown trout populations subject to stocking and population declines

    DEFF Research Database (Denmark)

    Hansen, Michael Møller; Fraser, Dylan J.; Meier, Kristian;

    2009-01-01

    Analyses of historical samples can provide invaluable information on changes to the genetic composition of natural populations resulting from human activities. Here, we analyse 21 microsatellite loci in historical (archived scales from 1927 to 1956) and contemporary samples of brown trout (Salmo...

  3. The effects of medieval dams on genetic divergence and demographic history in brown trout populations

    DEFF Research Database (Denmark)

    Hansen, Michael Møller; Limborg, Morten; Ferchaud, A.-L.;

    2014-01-01

    times ca. 600-800 years bp, providing strong evidence for establishment of dams in the Medieval as the factor causing divergence. Bayesian cluster analysis showed influence of stocked trout in several reference populations, but not in the focal lake and anadromous populations. Estimates of effective...

  4. Distribution of individual inbreeding coefficients, relatedness and influence of stocking on native anadromous brown trout ( Salmo trutta ) population structure

    DEFF Research Database (Denmark)

    Ruzzante, D.E.; Hansen, Michael Møller; Meldrup, Dorte

    2001-01-01

    We examined polymorphism at seven microsatellite loci in 4023 brown trout (Salmo trutta) collected from 32 tributaries to the Limfjord, Denmark (similar to 200 km) and from two hatcheries used for stocking. Populations differ in their estimated sizes and stocking histories. Mean individual...... inbreeding coefficients do not differ among locations within rivers. Relatedness varies between sites within rivers indicating varied local dynamics at a very small geographical scale. Relatedness is sometimes lower than expected among an equal number of simulated individuals with randomized genotypes...... is true of the eastern, more heavily stocked, area of the Limfjord. Here, a higher proportion of the genetic variance is distributed among locations within rivers than among rivers. Assignment tests reveal that the majority of trout (mean 77% of all fish) are more probably of local origin than hatchery...

  5. Extended spawning in brown trout (Salmo trutta populations from the Southern Iberian Peninsula: the role of climate variability

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    José E. Larios-López

    2015-01-01

    Full Text Available The reproductive periods of brown trout (Salmo trutta populations in 12 rivers in the Baetic Mountains in southern Spain were studied from 2008 to 2013. This area is an ecological and geographical limit for the distribution of this species in Europe. We found that the spawning period has been markedly extended in these fish. The mean spawning dates in the studied populations are consistent with the European trend at this latitude, but our data suggest that females from most of the populations that we studied are able to produce eggs from early October through late April or early May, yielding a reproductive period of between 150 and 170 days, the longest and most delayed brown trout reproduction periods that have been reported in the literature. We believe that such expanded spawning periods result primarily from the unpredictability of the Mediterranean climate, although it is possible that other factors may have contributed to the development of this reproductive behaviour. This hypothesis is discussed in the context of a comparison of our results with those found for other European S. trutta populations.

  6. Genetic detection of sex-specific dispersal in historical and contemporary populations of anadromous brown trout Salmo trutta

    DEFF Research Database (Denmark)

    Bekkevold, Dorte; Hansen, Michael Møller; Mensberg, Karen-Lise Dons

    2004-01-01

    The study of sex-biased dispersal has attracted considerable attention in birds and mammals, but less in other taxa, including fishes. We analysed sex-specific dispersal in historical (1910s and 1950s) and contemporary (1990s) samples of anadromous brown trout Salmo trutta. We tested the hypothesis...... that dispersal is unbiased using information from microsatellite DNA and applying an assignment index for 11 temporally and spatially separated samples. Our results are most consistent with brown trout dispersal being male biased, and provide no evidence of female bias. We found no evidence that dispersal...... patterns changed over time, indicating that stocking with hatchery strains did not affect sex-specific dispersal...

  7. Use of microsatellite markers for identification of indigenous brown trout in a geographical region heavily influenced by stocked domesticated trout

    DEFF Research Database (Denmark)

    Fritzner, Niels G.; Møller Hansen, Michael; Madsen, Steffen;

    2001-01-01

    Based on estimates of genetic differentiation between populations, assignment tests and analysis of isolation by distance, stocked populations of brown trout Salmo trutta of Funen Island, Denmark, had been genetically affected by domesticated trout, whereas the stocking of wild exogenous trout...

  8. Use of microsatellite markers for identification of indigenous brown trout in a geographical region heavily influenced by stocked domesticated trout

    DEFF Research Database (Denmark)

    Fritzner, N.G.; Hansen, Michael Møller; Madsen, S.S.;

    2001-01-01

    Based on estimates of genetic differentiation between populations, assignment tests and analysis of isolation by distance, stocked populations of brown trout Salmo trutta of Funen Island, Denmark, had been genetically affected by domesticated trout, whereas the stocking of wild exogenous trout into...

  9. Brown Trout removal effects on short-term survival and movement of Myxobolus cerebralis-resistant rainbow trout

    Science.gov (United States)

    Fetherman, Eric R.; Winkelman, Dana L.; Bailey, Larissa L.; Schisler, George J.; Davies, K.

    2015-01-01

    Following establishment of Myxobolus cerebralis (the parasite responsible for salmonid whirling disease) in Colorado, populations of Rainbow Trout Oncorhynchus mykissexperienced significant declines, whereas Brown Trout Salmo trutta densities increased in many locations across the state, potentially influencing the success of M. cerebralis-resistant Rainbow Trout reintroductions. We examined the effects of Brown Trout removal on the short-term (3-month) survival and movement of two crosses of reintroduced, M. cerebralis-resistant Rainbow Trout in the Cache la Poudre River, Colorado. Radio frequency identification passive integrated transponder tags and antennas were used to track movements of wild Brown Trout and stocked Rainbow Trout in reaches where Brown Trout had or had not been removed. Multistate mark–recapture models were used to estimate tagged fish apparent survival and movement in these sections 3 months following Brown Trout removal. A cross between the German Rainbow Trout and Colorado River Rainbow Trout strains exhibited similar survival and movement probabilities in the reaches, suggesting that the presence of Brown Trout did not affect its survival or movement. However, a cross between the German Rainbow Trout and Harrison Lake Rainbow Trout exhibited less movement from the reach in which Brown Trout had been removed. Despite this, the overall short-term benefits of the removal were equivocal, suggesting that Brown Trout removal may not be beneficial for the reintroduction of Rainbow Trout. Additionally, the logistical constraints of conducting removals in large river systems are substantial and may not be a viable management option in many rivers.

  10. Natural Selection and Genetic Drift: Neutral and adaptive genetic variability of hatchery versus wild populations in brown trout Salmo trutta

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    Tamara Schenekar

    2015-11-01

    Full Text Available Genetic drift and natural selection are two of the major forces shaping the genetic makeup of a population. Genetic drift reduces genetic variability due to the random loss of alleles during the transition from one generation to the next one. The smaller the population, the stronger genetic drift is. Natural selection favors the spread of specific alleles within a population over time, namely those alleles that are beneficial in the specific environment of this population. Individuals that carry alleles that are less advantageous have a lower probability to survive and reproduce. For establishing a captive population, very often, only a small number of individuals are taken and the number breeding individuals used to maintain the population is limited, thus increasing the amount of genetic drift. On the other hand, the drastically different environment in captivity (artificial diet, higher individual density, altered pathogen pressure, etc. may favor alleles that are maladaptive for individuals when they are released back in the wild, e.g. for stocking measures. We screened both, neutral and adaptive genetic markers, in order to assess the relative importance of genetic drift and selection pressure on wild and hatchery populations of Austrian brown trout. We confirm a strong positive selection pressure on an adaptive locus of the Major histocompatibility Complex (MHC, whereas the signal of this selection pressure was more pronounced in hatchery populations. This may either stem from stronger genetic drift in wild populations due to smaller effective population sizes or a stronger directional selection in these wild populations, whereby only particular genetic variants proved to be adaptive in each specific environment. Therefore, the alleles arising from the hatchery selection regime may be detrimental in the wild, which can lead to lower survival rates of stocked fish in wild environments.

  11. Investigating the phenology of seaward migration of juvenile brown trout (Salmo trutta) in two European populations

    DEFF Research Database (Denmark)

    Winter, E R.; Tummers, J. S.; Aarestrup, Kim;

    2016-01-01

    juvenile trout using passive integrated transponder (PIT) telemetry over an eight-month period in two European rivers; the River Deerness, north-east England, and the River Villestrup, Denmark. The incidence of autumn–winter seaward migration was greater in the Deerness than the Villestrup, with at least...

  12. Larger eggs in resident brown trout living in sympatry with anadromous brown trout

    DEFF Research Database (Denmark)

    Olofsson, H.; Mosegaard, Henrik

    1999-01-01

    Freshwater resident brown trout (Salmo trutta L.) in the stream Jorlandaan (southwestern Sweden) had larger eggs (range of actual mean egg wet weights, 65.9-108.5 mg) than both sympatric migratory trout (76.8-84.2 mg) and trout from five other Swedish streams with allopatric resident (23.7-80.1 mg...

  13. Phylogeographic study of brown trout from Serbia, based on mitochondrial DNA control region analysis

    OpenAIRE

    Snoj Aleš; Simonović Predrag; Sušnik Simona; Marić Saša

    2006-01-01

    Abstract In order to illuminate the phylogeography of brown trout (Salmo trutta) populations in the Balkan state of Serbia, the 561 bp 5'-end of mtDNA control region of 101 individuals originating from upland tributaries of the Danubian, Aegean and Adriatic drainages were sequenced and compared to corresponding brown trout sequences obtained in previous studies. Among 15 haplotypes found, 14 were considered native, representing the Danubian and Adriatic lineages of the brown trout, while one ...

  14. Long-term effective population sizes, temporal stability of genetic composition and potential for local adaptation in anadromous brown trout ( Salmo trutta ) populations

    DEFF Research Database (Denmark)

    Hansen, Michael Møller; Ruzzante, D.E.; Eg Nielsen, Einar;

    2002-01-01

    (3 km) river showed Ne greater than or equal to 300. Assuming a stepping-stone model of gene flow we considered the relative roles of gene flow, random genetic drift and selection to assess the possibilities for local adaptation. The requirements for local adaptation were fulfilled, but only......We examined the long-term temporal (1910s to 1990s) genetic variation at eight microsatellite DNA loci in brown trout (Salmo trutta L) collected from five anadromous populations in Denmark to assess the long-term stability of genetic composition and to estimate effective population sizes (N......-e). Contemporary and historical samples consisted of tissue and archived scales, respectively. Pairwise Theta(ST) estimates, a hierarchical analysis of molecular variance (AMOVA) and multidimensional scaling analysis of pairwise genetic distances between samples revealed much closer genetic relationships among...

  15. Brown trout demogenetics in the Belgian Ardennes : an individual-based modelling approach

    OpenAIRE

    Frank, Béatrice

    2012-01-01

    The brown trout (Salmo trutta L.) is one of the vertebrate species presenting the highest degree of intraspecific biological diversity. Human activities are threatening this biodiversity, and many endemic populations now face a medium-term risk of extinction. An individual-based model called DemGenTrout was developed to improve the management of these populations, by providing (i) a descriptive tool to study the functioning of a brown trout population at the stream scale, (ii) a predictive to...

  16. 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...

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

    Science.gov (United States)

    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.

  18. Movement and mortality of stocked brown trout in a stream

    DEFF Research Database (Denmark)

    Aarestrup, Kim; Jepsen, Niels; Koed, Anders;

    2005-01-01

    The movement and mortality of stocked brown trout Salmo trutta were investigated using radio telemetry. Four brown trout left the study area whereas the remaining fish were stationary. After 5 weeks, 13 out of 50 tagged brown trout were still alive in the stream. Surviving fish had a significantly...

  19. The Brown Trout (Salmo trutta L. at the Northeastern Border of the Species Area

    Directory of Open Access Journals (Sweden)

    Makhrov Alexander

    2013-03-01

    Full Text Available The level of ecological and morphological plasticity as well as genetic diversity of brown trout at the northeastern border of its species area are about as high as in the central part, and the population structure is equally complex. Apparently, abiotic factors (competition with other salmonids rather than biotic ones prevent the brown trout area from expanding.

  20. The Brown Trout (Salmo trutta L.) at the Northeastern Border of the Species Area

    OpenAIRE

    Makhrov Alexander

    2013-01-01

    The level of ecological and morphological plasticity as well as genetic diversity of brown trout at the northeastern border of its species area are about as high as in the central part, and the population structure is equally complex. Apparently, abiotic factors (competition with other salmonids) rather than biotic ones prevent the brown trout area from expanding.

  1. Climate-driven population responses of resident brown trout, Salmo trutta: Trends and future projections

    OpenAIRE

    2016-01-01

    The climate is changing at an alarming rate with consequences such as species and population extinctions, changes in species distribution and phenology. However, mechanisms underlying these global trends are not well understood, especially at a population level. Climate effects on demographic traits and population dynamics have recently received increasing attention as key importance for understanding the ecological impacts of climate change. The effects on demographic traits might vary acros...

  2. Population and family structure of brown trout, Salmo trutta, in a Mediterranean stream

    DEFF Research Database (Denmark)

    Vera, Manuel; Sanz, Nuria; Hansen, Michael Møller;

    2010-01-01

    The physical arrangement of closely related individuals is expected to significantly influence the pattern of population genetic structure. For example, if related individuals are non-randomly distributed and included in samples, this may lead to exaggerated conclusions about genetic differentiat......The physical arrangement of closely related individuals is expected to significantly influence the pattern of population genetic structure. For example, if related individuals are non-randomly distributed and included in samples, this may lead to exaggerated conclusions about genetic...

  3. Introduced brown trout alter native acanthocephalan infections in native fish.

    Science.gov (United States)

    Paterson, Rachel A; Townsend, Colin R; Poulin, Robert; Tompkins, Daniel M

    2011-09-01

    1. Native parasite acquisition provides introduced species with the potential to modify native host-parasite dynamics by acting as parasite reservoirs (with the 'spillback' of infection increasing the parasite burdens of native hosts) or sinks (with the 'dilution' of infection decreasing the parasite burdens of native hosts) of infection. 2. In New Zealand, negative correlations between the presence of introduced brown trout (Salmo trutta) and native parasite burdens of the native roundhead galaxias (Galaxias anomalus) have been observed, suggesting that parasite dilution is occurring. 3. We used a multiple-scale approach combining field observations, experimental infections and dynamic population modelling to investigate whether native Acanthocephalus galaxii acquisition by brown trout alters host-parasite dynamics in native roundhead galaxias. 4. Field observations demonstrated higher infection intensity in introduced trout than in native galaxias, but only small, immature A. galaxii were present in trout. Experimental infections also demonstrated that A. galaxii does not mature in trout, although parasite establishment and initial growth were similar in the two hosts. Taken together, these results support the hypothesis that trout may serve as an infection sink for the native parasite. 5. However, dynamic population modelling predicts that A. galaxii infections in native galaxias should at most only be slightly reduced by dilution in the presence of trout. Rather, model exploration indicates parasite densities in galaxias are highly sensitive to galaxias predation on infected amphipods, and to relative abundances of galaxias and trout. Hence, trout presence may instead reduce parasite burdens in galaxias by either reducing galaxias density or by altering galaxias foraging behaviour. PMID:21426342

  4. A trial of two trouts: Comparing the impacts of rainbow and brown trout on a native galaxiid

    Science.gov (United States)

    Young, K.A.; Dunham, J.B.; Stephenson, J.F.; Terreau, A.; Thailly, A.F.; Gajardo, G.; de Leaniz, C. G.

    2010-01-01

    Rainbow trout Oncorhynchus mykiss and brown trout Salmo trutta are the world's two most widespread exotic fishes, dominate the fish communities of most cold-temperate waters in the southern hemisphere and are implicated in the decline and extirpation of native fish species. Here, we provide the first direct comparison of the impacts of rainbow and brown trout on populations of a native fish by quantifying three components of exotic species impact: range, abundance and effect. We surveyed 54 small streams on the island of Chilo?? in Chilean Patagonia and found that the rainbow trout has colonized significantly more streams and has a wider geographic range than brown trout. The two species had similar post-yearling abundances in allopatry and sympatry, and their abundances depended similarly on reach-level variation in the physical habitat. The species appeared to have dramatically different effects on native drift-feeding Aplochiton spp., which were virtually absent from streams invaded by brown trout but shared a broad sympatric range with rainbow trout. Within this range, the species' post-yearling abundances varied independently before and after controlling for variation in the physical habitat. In the north of the island, Aplochiton spp. inhabited streams uninvaded by exotic trouts. Our results provide a context for investigating the mechanisms responsible for apparent differences in rainbow and brown trout invasion biology and can help inform conservation strategies for native fishes in Chilo?? and elsewhere. ?? 2010 The Authors. Journal compilation ?? 2010 The Zoological Society of London.

  5. Habitat modeling for brown trout population in alpine region of Slovenia with focus on determination of preference functions, fuzzy rules and fuzzy sets

    Science.gov (United States)

    Santl, Saso; Carf, Masa; Preseren, Tanja; Jenic, Aljaz

    2013-04-01

    Water withdrawals and consequently reduction of discharges in river streams for different water uses (hydro power, irrigation, etc.) usually impoverish habitat suitability for naturally present river fish fauna. In Slovenia reduction of suitable habitats resulting from water abstractions frequently impacts local brown trout (Salmo truta) populations. This is the reason for establishment of habitat modeling which can qualitatively and quantitatively support decision making for determination of the environmental flow and other mitigation measures. Paper introduces applied methodology for habitat modeling where input data preparation and elaboration with required accuracy has to be considered. For model development four (4) representative and heterogeneous sampling sites were chosen. Two (2) sampling sections were located within the sections with small hydropower plants and were considered as sections affected by water abstractions. The other two (2) sampling sections were chosen where there are no existing water abstractions. Precise bathymetric mapping for chosen river sections has been performed. Topographic data and series of discharge and water level measurements enabled establishment of calibrated hydraulic models, which provide data on water velocities and depths for analyzed discharges. Brief field measurements were also performed to gather required data on dominant and subdominant substrate size and cover type. Since the accuracy of fish distribution on small scale is very important for habitat modeling, a fish sampling method had to be selected and modified for existing river microhabitats. The brown trout specimen's locations were collected with two (2) different sampling methods. A method of riverbank observation which is suitable for adult fish in pools and a method of electro fishing for locating small fish and fish in riffles or hiding in cover. Ecological and habitat requirements for fish species vary regarding different fish populations as well as eco

  6. Proliferative kidney disease in brown trout – infection level, pathology and mortality under field conditions

    OpenAIRE

    Schmidt-Posthaus, Heike; Hirschi, Regula; Schneider, Ernst

    2015-01-01

    Proliferative kidney disease (PKD) is an emerging disease threatening wild salmonid populations. In temperature-controlled aquaria, PKD can cause mortality rates of up to 85% in rainbow trout. So far, no data about PKD-related mortality in wild brown trout Salmo trutta fario are available. The aim of this study was to investigate mortality rates and pathology in brown trout kept in a cage within a natural river habitat known to harbor Tetracapsuloides bryosalmonae. Young-of-the-year (YOY) ...

  7. On behavioural responses to smell and sight of alpine bullhead Cottus poecilopus Heckel for an allopatric and a sympatric population of brown trout Salmo trutta L.

    OpenAIRE

    2007-01-01

    Freshwater sculpins and salmonids coexist in many streams throughout the Northern hemisphere, and often constitute an important component of stream ecosystems. Alpine bullhead Cottus poecilopus Heckel have been known to predate eggs and fry of brown trout Salmo trutta L., and also to function as a competitor to older brown trout for habitat and prey items. This study was designed to examine possible behavioural differences in activity level and positioning between a sympatric and an allopatri...

  8. Evidence of salmon lice-induced mortality of anadromous brown trout (Salmo trutta) in the Hardangerfjord, Norway

    OpenAIRE

    Skaala, Øystein; Kålås, Steinar; Borgstrøm, Reidar

    2013-01-01

    The Hardangerfjord, western Norway, is an area with a high concentration of salmon farms, high levels of infection of salmon lice in anadromous brown trout, and declining trout populations. This study assessed the marine survival rate of anadromous trout from the River Guddalselva, in the central part of the fjord, and tested the hypothesis that trout populations in this area are depressed by salmon lice infection. From 2001 to 2011, all descending smolts and trout returning from the fjord we...

  9. Utilisation of brown trout by Acanthocephalus clavula (Acanthocephala) in brown trout (Salmo trutta) in an Irish lake: is this evidence of a host shift?

    OpenAIRE

    HOLLAND, CELIA

    2004-01-01

    PUBLISHED The population biology of the fish acanthocephalan Acanthocephalus clavula was described from 161 wild brown trout, Salmo trutta sampled over a two-year period in Clogher Lake in the west of Ireland. Overall prevalence of the parasite was 86% and the mean abundance was 53 worms per fish. Despite the presence of large numbers of worms in the trout very few females (2%) attained full reproductive maturity. This suggests that trout is an accidental host. A sample of yellow eels, Ang...

  10. Sea growth of anadromous brown trout ( Salmo trutta)

    Science.gov (United States)

    de Leeuw, J. J.; ter Hofstede, R.; Winter, H. V.

    2007-08-01

    Sea growth rates were studied in anadromous brown trout caught in Lake IJsselmeer, The Netherlands. Growth in the first year at sea was estimated at 26 cm from length-frequency distributions, and at 21 cm from back-calculated growth rates from scale readings. These estimates are considerably higher than sea growth rates observed in populations at higher latitudes (Norway, Sweden), but compare well with the limited information on sea growth rates estimated for anadromous trout in the River Rhine and rivers in Normandy (France).

  11. 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...

  12. Spatially and temporally fluctuating selection at non-MHC immune genes: evidence from TAP polymorphism in populations of brown trout ( Salmo trutta , L.)

    DEFF Research Database (Denmark)

    Jensen, L.F.; Hansen, Michael Møller; Mensberg, Karen-Lise Dons;

    2008-01-01

    molecules that are central to the major histocompatibility complex (MHC) class I restricted antigen presentation and thus integral components in the adaptive immune system. As such, they could be influenced by selection, driven by pathogens and parasites in a manner similar to MHC genes. Analysis of allele......Temporal samples of Danish brown trout (Salmo trutta) from populations representing varying geographical scales were analysed using eight putatively neutral microsatellite loci and two microsatellite loci embedded in TAP genes (Transporter associated with Antigen Processing). These genes encode....... Moreover, signals of divergent selection among temporal samples within localities suggest that selection also might fluctuate at a temporal scale. These results suggest that immune genes other than the classical MHC class I and II might be subject to selection and warrant further studies of functional...

  13. Phylogenetic status of brown trout Salmo trutta populations in five rivers from the southern Caspian Sea and two inland lake basins, Iran: a morphogenetic approach.

    Science.gov (United States)

    Hashemzadeh Segherloo, I; Farahmand, H; Abdoli, A; Bernatchez, L; Primmer, C R; Swatdipong, A; Karami, M; Khalili, B

    2012-10-01

    Interrelationships, origin and phylogenetic affinities of brown trout Salmo trutta populations from the southern Caspian Sea basin, Orumieh and Namak Lake basins in Iran were analysed from complete mtDNA control region sequences, 12 microsatellite loci and morphological characters. Among 129 specimens from six populations, seven haplotypes were observed. Based on mtDNA haplotype data, the Orumieh and southern Caspian populations did not differ significantly, but the Namak basin-Karaj population presented a unique haplotype closely related to the haplotypes of the other populations (0·1% Kimura two-parameter, K2P divergence). All Iranian haplotypes clustered as a distinct group within the Danube phylogenetic grouping, with an average K2P distance of 0·41% relative to other Danubian haplotypes. The Karaj haplotype in the Namak basin was related to a haplotype (Da26) formerly identified in the Tigris basin in Turkey, to a Salmo trutta oxianus haplotype from the Aral Sea basin, and to haplotype Da1a with two mutational steps, as well as to other Iranian haplotypes with one to two mutational steps, which may indicate a centre of origin in the Caspian basin. In contrast to results of the mtDNA analysis, more pronounced differentiation was observed among the populations studied in the morphological and microsatellite DNA data, except for the two populations from the Orumieh basin, which were similar, possibly due to anthropogenic causes.

  14. Factors influencing the spawning migration of female anadromous brown trout

    DEFF Research Database (Denmark)

    Svendsen, Jon Christian; Koed, Anders; Aarestrup, Kim

    2004-01-01

    Radio telemetry was employed to study movements of adult female anadromous brown trout Salmo trutta (sea trout) during upstream spawning migration and following spawning in a stream with tributaries. Sea trout were monitored by manual tracking and by automatic listening stations. The latter...

  15. 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.

  16. Proliferative kidney disease in brown trout: infection level, pathology and mortality under field conditions.

    Science.gov (United States)

    Schmidt-Posthaus, Heike; Hirschi, Regula; Schneider, Ernst

    2015-05-21

    Proliferative kidney disease (PKD) is an emerging disease threatening wild salmonid populations. In temperature-controlled aquaria, PKD can cause mortality rates of up to 85% in rainbow trout. So far, no data about PKD-related mortality in wild brown trout Salmo trutta fario are available. The aim of this study was to investigate mortality rates and pathology in brown trout kept in a cage within a natural river habitat known to harbor Tetracapsuloides bryosalmonae. Young-of-the-year (YOY) brown trout, free of T. bryosalmonae, were exposed in the River Wutach, in the northeast of Switzerland, during 3 summer months. Samples of wild brown trout caught by electrofishing near the cage location were examined in parallel. The incidence of PKD in cage-exposed animals (69%) was not significantly different to the disease prevalence of wild fish (82 and 80% in the upstream and downstream locations, respectively). The mortality in cage-exposed animals, however, was as low as 15%. At the termination of the exposure experiment, surviving fish showed histological lesions typical for PKD regression, suggesting that many YOY brown trout survive the initial infection. Our results at the River Wutach suggest that PKD in brown trout does not always result in high mortality under natural conditions. PMID:25993888

  17. Proliferative kidney disease in brown trout: infection level, pathology and mortality under field conditions.

    Science.gov (United States)

    Schmidt-Posthaus, Heike; Hirschi, Regula; Schneider, Ernst

    2015-05-21

    Proliferative kidney disease (PKD) is an emerging disease threatening wild salmonid populations. In temperature-controlled aquaria, PKD can cause mortality rates of up to 85% in rainbow trout. So far, no data about PKD-related mortality in wild brown trout Salmo trutta fario are available. The aim of this study was to investigate mortality rates and pathology in brown trout kept in a cage within a natural river habitat known to harbor Tetracapsuloides bryosalmonae. Young-of-the-year (YOY) brown trout, free of T. bryosalmonae, were exposed in the River Wutach, in the northeast of Switzerland, during 3 summer months. Samples of wild brown trout caught by electrofishing near the cage location were examined in parallel. The incidence of PKD in cage-exposed animals (69%) was not significantly different to the disease prevalence of wild fish (82 and 80% in the upstream and downstream locations, respectively). The mortality in cage-exposed animals, however, was as low as 15%. At the termination of the exposure experiment, surviving fish showed histological lesions typical for PKD regression, suggesting that many YOY brown trout survive the initial infection. Our results at the River Wutach suggest that PKD in brown trout does not always result in high mortality under natural conditions.

  18. Use of similar habitat by cutthroat trout and brown trout in a regulated river during winter

    Science.gov (United States)

    Dare, M.R.; Hubert, W.A.

    2003-01-01

    Few differences in habitat use were observed between cutthroat trout and brown trout during winter in the Shoshone River, a regulated river in northwestern Wyoming. Radio-tagged fish of 20-30 cm total length were found in pool habitat five to six times more frequently than would be expected if they were using pools in proportion to pool availability. Nevertheless, run habitat was most frequently used by both species. The microhabitat characteristics at locations of each species were similar when in both pools and runs, however, habitat use was variable suggesting that a variety of microhabitats were suitable over-wintering habitat. Brown trout were more frequently associated with boulder cover than were cutthroat trout. Cutthroat trout used large pools that provided refuge from high water velocities more frequently that brown trout. Cutthroat trout and brown trout were found at similar distances from the bank except in late February when cutthroat trout were farther from the bank. Both species moved frequently during the winter, but cutthroat trout showed a greater propensity than brown trout to move long distances. This study suggests that during a mild winter in a stable environment, these species were able to overwinter successfully in a variety of habitats.

  19. Intercohort density dependence drives brown trout habitat selection

    Science.gov (United States)

    Ayllón, Daniel; Nicola, Graciela G.; Parra, Irene; Elvira, Benigno; Almodóvar, Ana

    2013-01-01

    Habitat selection can be viewed as an emergent property of the quality and availability of habitat but also of the number of individuals and the way they compete for its use. Consequently, habitat selection can change across years due to fluctuating resources or to changes in population numbers. However, habitat selection predictive models often do not account for ecological dynamics, especially density dependent processes. In stage-structured population, the strength of density dependent interactions between individuals of different age classes can exert a profound influence on population trajectories and evolutionary processes. In this study, we aimed to assess the effects of fluctuating densities of both older and younger competing life stages on the habitat selection patterns (described as univariate and multivariate resource selection functions) of young-of-the-year, juvenile and adult brown trout Salmo trutta. We observed all age classes were selective in habitat choice but changed their selection patterns across years consistently with variations in the densities of older but not of younger age classes. Trout of an age increased selectivity for positions highly selected by older individuals when their density decreased, but this pattern did not hold when the density of younger age classes varied. It suggests that younger individuals are dominated by older ones but can expand their range of selected habitats when density of competitors decreases, while older trout do not seem to consider the density of younger individuals when distributing themselves even though they can negatively affect their final performance. Since these results may entail critical implications for conservation and management practices based on habitat selection models, further research should involve a wider range of river typologies and/or longer time frames to fully understand the patterns of and the mechanisms underlying the operation of density dependence on brown trout habitat

  20. Seasonal movement of brown trout in a southern appalachian river

    Science.gov (United States)

    Burrell, K.H.; Isely, J.J.; Bunnell, D.B., Jr.; Van Lear, D. H.; Dolloff, C.A.

    2000-01-01

    Radio telemetry was used to evaluate the seasonal movement, activity level, and home range size of adult brown trout Salmo trutta in the Chattooga River watershed, one of the southernmost coldwater stream systems in the United States. In all, 27 adult brown trout (262-452 mm total length) were successfully monitored from 16 November 1995 to 15 December 1996. During the day, adult brown trout were consistently found in small, well-established home ranges of less than 270 m in stream length. However, 8 of a possible 18 study fish made spawning migrations during a 2-week period in November 1996. The daytime locations of individual fish were restricted to a single pool or riffle-pool combination, and fish were routinely found in the same location over multiple sampling periods. Maximum upstream movement during spawning was 7.65 km, indicating that brown trout in the Chattooga River have the ability to move long distances. Spawning brown trout returned to their prespawning locations within a few days after spawning. Brown trout maintained larger home ranges in winter than in other seasons. When spawning-related movement was deleted from the analysis, brown trout moved more on a weekly basis in fall than in summer. Brown trout were more active in fall and winter than in spring and summer. Apart from spawning migrations, displacement from established home ranges was not observed for any fish in the study. Although summer water temperatures reached and exceeded reported upper thermal-preference levels, brown trout did not move to thermal refuge areas in nearby tributaries during the stressful summer periods.

  1. Factors influencing brown trout reproductive success in Ozark tailwater rivers

    Science.gov (United States)

    Pender, D.R.; Kwak, T.J.

    2002-01-01

    The reproductive success of brown trout Salmo trutta in White River, Arkansas, tailwater reaches is highly variable, resulting in the need for supplemental stocking. A better understanding of the physical and biotic factors affecting reproduction and survival would enhance the contribution of wild fish. We compared fecundity, reproductive chronology, physical habitat, water quality, trout density, food availability, diet, predation, and competitive interactions among four tailwater reaches to identify factors influencing brown trout reproductive success. The fecundity and condition factor of prespawning brown trout were significantly lower at Beaver Tailwater, a reach known for reproductive failure, than at other sites, among which no differences were found. Brown trout spawning was observed from 11 October to 23 November 1996, and juvenile emergence began on 28 February 1997. Significant among-site differences were detected for spawning and juvenile microhabitat variables, but the variables fell within or near suitable or optimal ranges reported in the literature for this species. Age-0 brown trout density differed significantly among sites, but growth and condition did not. Predation by Ozark sculpin Cottus hypselurus on trout eggs or age-0 trout of any species was not observed among the 418 stomachs examined. Ozark sculpin density and diet overlap with age-0 brown trout were highest and invertebrate food availability and water fertility were lowest at Beaver Tailwater relative to the other reaches. Our findings indicate that differences in trophic conditions occur among tailwater reaches, and a lower system productive capacity was identified at Beaver Tailwater. We suggest that management efforts include refining the multispecies trout stocking regime to improve production efficiency, enhancing flow regulation, and increasing habitat complexity to increase invertebrate and fish productivity. Such efforts may lead to improved natural reproduction and the

  2. Diel movement of brown trout in a southern Appalachian River

    Science.gov (United States)

    Bunnell, D.B., Jr.; Isely, J.J.; Burrell, K.H.; Van Lear, D. H.

    1998-01-01

    Radio telemetry was used to monitor the diel movement of 22 brown trout Salmo trutta (268-446 mm in total length, TL) in the Chattooga River watershed. Forty-seven diel tracks, locating individuals once per hour for 24 consecutive hours, were collected for four consecutive seasons. High variability in movement both within and among individual brown trout resulted in similar seasonal means in total distance moved, diel range, and displacement. The majority of fish moved a total distance of less than 80 m within a diel range of less than 80 m and had a displacement of less than 10 m. Brown trout were more likely to occur in pool habitat independent of season or period of the day. Hourly movement patterns differed among seasons. During the winter and fall, trout moved only around sunrise; during the spring, they moved around sunrise, sunset, and intermittently throughout the night. Large brown trout (>375 mm, TL) were found to move greater total distances and establish wider diel ranges than small brown trout. Overall, most brown trout exhibited restricted diel movement within a single riffle-pool or run-pool sequence.

  3. Heavy metal contamination and hepatic toxicological responses in brown trout (Salmo trutta from the Kerguelen Islands

    Directory of Open Access Journals (Sweden)

    Ali Jaffal

    2015-09-01

    Full Text Available The Kerguelen Islands include various species of freshwater fish such as brown trout (Salmo trutta. These trout are among the most isolated from direct anthropogenic impact worldwide. This study was designed to analyse cadmium (Cd and copper (Cu concentrations in the liver of Kerguelen brown trout, and to assess the possible impacts of these metals on hepatic histopathology and oxidative stress parameters (superoxide dismutase and catalase activity and glutathione levels. Trout were caught in the Château River, the Studer Lakes and the Ferme Pond, close to the scientific station of the Kerguelen Islands, corresponding to three morphotypes (river, lake and station. Kerguelen trouts’ hepatic concentrations of Cd and Cur were similar to those reported in previous studies in salmonids populations from areas under anthropological impacts. Clear hepatic disturbances (fibrosis, nuclear alteration, increased immune response, melanomacrophage centres [MMCs] were observed in all tested trout. A similar histo-pathological trend was observed among the trout from the three morphotypes but anti-oxidative responses were higher in the trout from the “station” morphotype. Hepatic alterations and the presence of MMCs in the livers of Kerguelen brown trout may be related to the high levels of Cd and Cu measured in this fish at all sampling sites.

  4. Brown Trout Distribution, Pacific Northwest (updated March, 2006)

    Data.gov (United States)

    Pacific States Marine Fisheries Commission — This dataset is a record of fish distribution and activity for BROWN TROUT contained in the StreamNet database. This feature class was created based on linear event...

  5. Seasonal movement of brown trout in the Clinch River, Tennessee

    Science.gov (United States)

    Bettinger, J.M.; Bettoli, P.W.

    2004-01-01

    We used radiotelemetry to monitor the seasonal movements of trophy-size brown trout Salmo trutta in the Clinch River below Norris Dam, Tennessee, to determine whether establishing a special-regulation reach to reduce fishing mortality was a viable management option. Fifteen brown trout (size range, 430-573 mm total length) collected from the river were implanted with radio transmitters between November 1997 and May 1998. Forty-seven percent of these fish died or expelled their transmitters within 50 d postsurgery. The range of movement for surviving brown trout was significantly larger in fall (geometric mean range = 5,111 m) than in any other season. Four brown trout that were monitored for more than 1 year exhibited a limited range of movement (5 km) during the fall season, presumably to spawn. Brown trout also moved more during the fall than in any other season. Harvest restrictions applied to a specific reach of the Clinch River would reduce the exploitation of brown trout in that reach for most of the year but not during the fall, when many fish undertake extensive spawning migrations.

  6. Neighbouring populations, opposite dynamics: influence of body size and environmental variation on the demography of stream-resident brown trout (Salmo trutta).

    Science.gov (United States)

    Fernández-Chacón, Albert; Genovart, Meritxell; Álvarez, David; Cano, José M; Ojanguren, Alfredo F; Rodriguez-Muñoz, Rolando; Nicieza, Alfredo G

    2015-06-01

    In organisms such as fish, where body size is considered an important state variable for the study of their population dynamics, size-specific growth and survival rates can be influenced by local variation in both biotic and abiotic factors, but few studies have evaluated the complex relationships between environmental variability and size-dependent processes. We analysed a 6-year capture-recapture dataset of brown trout (Salmo trutta) collected at 3 neighbouring but heterogeneous mountain streams in northern Spain with the aim of investigating the factors shaping the dynamics of local populations. The influence of body size and water temperature on survival and individual growth was assessed under a multi-state modelling framework, an extension of classical capture-recapture models that considers the state (i.e. body size) of the individual in each capture occasion and allows us to obtain state-specific demographic rates and link them to continuous environmental variables. Individual survival and growth patterns varied over space and time, and evidence of size-dependent survival was found in all but the smallest stream. At this stream, the probability of reaching larger sizes was lower compared to the other wider and deeper streams. Water temperature variables performed better in the modelling of the highest-altitude population, explaining over a 99 % of the variability in maturation transitions and survival of large fish. The relationships between body size, temperature and fitness components found in this study highlight the utility of multi-state approaches to investigate small-scale demographic processes in heterogeneous environments, and to provide reliable ecological knowledge for management purposes. PMID:25604919

  7. Factors influencing the distribution of brown trout (Salmo trutta) in a mountain stream: Implications for brown trout invasion success

    OpenAIRE

    Meredith, Christy

    2012-01-01

    Brown trout (Salmo trutta), one of the world’s most successful introduced species, negatively impacts native aquatic communities through predation, competition, and ecosystemlevel effects. Thus, there is a need to understand factors controlling the distribution of exotic brown trout in river systems, in order to prioritize and develop conservation and management strategies. Within the context of invasion success, I investigated how the physical template of the Logan River influences the distr...

  8. Using genetic with stable isotope analyses to investigate hybridization between Atlantic salmon, sea-run and stream resident brown trout in a small stream

    OpenAIRE

    Roussel, Jean-Marc; Charles, Katia; Baglinière, Jean-Luc; Guyomard, René; Ombredane, Dominique

    2005-01-01

    Brown trout Salmo trutta and Atlantic salmon Salmo salar can interbreed and produce viable hybrid offspring. Literature indicates that maternal species can either be brown trout (North America) or Atlantic salmon (South- ern Europe and Ireland), and bidirectional hybridization has also been reported (England, Northern Europe and subantarctic French Territory). In coastal rivers where both species are sympatric, brown trout populations often split into two morphs, stream residents ...

  9. Movement and survival of brown trout and rainbow trout in an ozark tailwater river

    Science.gov (United States)

    Quinn, J.W.; Kwak, T.J.

    2011-01-01

    We evaluated the movement of adult brown trout Salmo trutta and rainbow trout Oncorhynchus mykiss in relation to a catch-andrelease area in the White River downstream from Beaver Dam, Arkansas. Nine fish of each species were implanted with radio transmitters and monitored from July 1996 to July 1997. The 1.5- km river length of a catch-and-release area (closed to angler harvest) was greater than the total linear range of 72% of the trout (13 of 18 fish), but it did not include two brown trout spawning riffles, suggesting that it effectively protects resident fish within the catch-and-release area except during spawning. The total detected linear range of movement varied from 172 to 3,559 m for brown trout and from 205 to 3,023mfor rainbow trout. The movements of both species appeared to be generally similar to that in unregulated river systems. The annual apparent survival of both trout species was less than 0.40, and exploitation was 44%.Management to protect fish on spawning riffles may be considered if management for wild brown trout becomes a priority. ?? American Fisheries Society 2011.

  10. 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.

  11. Sibship within samples of brown trout ( Salmo trutta ) and implications for supportive breeding

    DEFF Research Database (Denmark)

    Hansen, Michael Møller; Jensen, L. F.

    2005-01-01

    We analysed family relationships among brown trout from two small tributary populations that have been suggested as a source of individuals for supportive breeding, using variation at eight microsatellite loci. As a control, we analysed a sample of supposedly unrelated individuals representing a...

  12. Ultrastructural changes in the hepatocytes of juvenile rainbow trout and mature brown trout exposed to copper or zinc

    Science.gov (United States)

    Leland, H.V.

    1983-01-01

    Morphological changes in hepatocytes of mature brown trout (Salmo trutta Linnaeus) and juvenile rainbow trout (Salmo gairdneri Richardson), accompanying chronic exposures to copper and zinc, were examined by transmission electron microscopy. At a concentration of copper not inhibitory to the final stages of gonadal development or spawning of brown trout, structural alterations included contraction of mitochondria and a tendency for nuclei to be slightly enlarged. Concentrations of copper or zinc lethal to a small fraction (10% and 4%, respectively) of a population of juvenile rainbow trout exposed for 42 d during larval and early juvenile development caused hepatocyte changes in survivors indicative of a reduction in ability to maintain intracellular water and cation balance and possible intranuclear metal sequestering. Specific structural alterations included increased vesiculation of rough endoplasmic reticulum, an increase in the abundance of electron-dense particles in the nucleus, increases in the numbers of multilaminar and globular inclusions, pooling of glycogen, increased autophagocytic activity and an increase in the number of necrotic cells. At advanced stages of toxicosis (concentrations of copper or zinc lethal to approximately 50% of the juveniles exposed for 42 d during development), loss in integrity of mitochondrial membranes, rupturing of plasma and nuclear membranes, separation of granular and fibrillar nuclear components, fragmentation of endoplasmic reticulum, and extensive autophagic vacuolization were significant features of hepatocytes of surviving juvenile rainbow trout. ?? 1983.

  13. Diel resource partitioning among juvenile Atlantic Salmon, Brown Trout, and Rainbow Trout during summer

    Science.gov (United States)

    Johnson, James H.; McKenna Jr, James E.

    2015-01-01

    Interspecific partitioning of food and habitat resources has been widely studied in stream salmonids. Most studies have examined resource partitioning between two native species or between a native species and one that has been introduced. In this study we examine the diel feeding ecology and habitat use of three species of juvenile salmonids (i.e., Atlantic Salmon Salmo salar, Brown Trout Salmo trutta, and Rainbow Trout Oncorhynchus mykiss) in a tributary of Skaneateles Lake, New York. Subyearling Brown Trout and Rainbow Trout fed more heavily from the drift than the benthos, whereas subyearling Atlantic Salmon fed more from the benthos than either species of trout. Feeding activity of Atlantic Salmon and Rainbow Trout was similar, with both species increasing feeding at dusk, whereas Brown Trout had no discernable feeding peak or trough. Habitat availability was important in determining site-specific habitat use by juvenile salmonids. Habitat selection was greater during the day than at night. The intrastream, diel, intraspecific, and interspecific variation we observed in salmonid habitat use in Grout Brook illustrates the difficulty of acquiring habitat use information for widespread management applications.

  14. Snorkeling as an alternative to depletion electrofishing for assessing cutthroat trout and brown trout in stream pools

    Science.gov (United States)

    Joyce, M.P.; Hubert, W.A.

    2003-01-01

    We compared abundance and length structure estimates of cutthroat trout (Oncorhynchus clarki) and brown trout (Salmo trutta) of 15 cm total length or greater obtained by snorkeling in stream pools with estimates obtained by depletion electrofishing. We sampled 12 pools in each of two streams formed by large springs in the Salt River Valley of western Wyoming. Snorkeling counts provided a relatively accurate index of depletion electrofishing estimates of abundance of cutthroat trout, but not brown trout. Linear regression analysis showed that snorkeling counts were significantly related to depletion electrofishing estimates for both cutthroat trout (P brown trout (P = 0.002), but the coefficient of determination for brown trout (r2 = 0.33) was low compared to cutthroat trout (r2 = 0.95). Frequencies of fish in three length classes observed by snorkeling and depletion electrofishing were close to being significantly different for cutthroat trout (P = 0.066) and substantially different for brown trout (P = 0.005). Snorkeling frequently failed to observe fish in the shortest length class (15-29 cm total length) of both cutthroat trout and brown trout.

  15. Phylogeographic study of brown trout from Serbia, based on mitochondrial DNA control region analysis

    Directory of Open Access Journals (Sweden)

    Snoj Aleš

    2006-06-01

    Full Text Available Abstract In order to illuminate the phylogeography of brown trout (Salmo trutta populations in the Balkan state of Serbia, the 561 bp 5'-end of mtDNA control region of 101 individuals originating from upland tributaries of the Danubian, Aegean and Adriatic drainages were sequenced and compared to corresponding brown trout sequences obtained in previous studies. Among 15 haplotypes found, 14 were considered native, representing the Danubian and Adriatic lineages of the brown trout, while one haplotype (ATcs1, found only in two individuals originating from two stocked rivers, corresponded to the Atlantic lineage and was considered introduced. Native haplotypes exhibited a strong geographic pattern of distribution: the Danubian haplotypes were strictly confined to the Danubian drainage, while the Adriatic haplotypes dominated in the Aegean and Adriatic drainages; most of the total molecular variance (69% was attributed to differences among the drainages. Phylogenetic reconstruction, supplemented with seven haplotypes newly described in this study, suggested a sister position of the Atlantic-Danubian and Adriatic-Mediterranean-marmoratus ("southern" phylogenetic group, and pointed to the existence of a distinct clade, detected within the "southern" group. The data obtained confirmed our expectation of the existence of high genetic diversity in Balkan trout populations, and we recommend more widespread surveys covering trout stocks from the region.

  16. 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...

  17. Sea growth of anadromous brown trout (Salmo trutta)

    NARCIS (Netherlands)

    Leeuw, de J.J.; Hofstede, ter R.; Winter, H.V.

    2007-01-01

    Sea growth rates were studied in anadromous brown trout caught in Lake IJsselmeer, The Netherlands. Growth in the first year at sea was estimated at 26 cm from length-frequency distributions, and at 21 cm from back-calculated growth rates from scale readings. These estimates are considerably higher

  18. 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)

  19. ANALYSE DE LA VARIABILITÉ DE LA CROISSANCE D'UNE POPULATION DE TRUITE COMMUNE (SALMO TRUTTA L. DANS UN TORRENT PYRÉNÉEN. GROWTH VARIABILITY ANALYSIS OF A BROWN TROUT (SALMO TRUTTA L. POPULATION IN A PYRENEAN MOUNTAIN STREAM.

    Directory of Open Access Journals (Sweden)

    LAGARRIGUE T.

    2008-05-01

    discuté. The brown trout population of the Neste d'Oueil, a Pyrenean tributary of the Garonne river, was studied between July 1996 and March 1999. During the period of two years and nine months, nine sampling experiments were carried out in February-March, July and September on two sectors of the river. Thus, we could follow the seasonal variation of growth, total density and total biomass of brown trout. Moreover, 652 brown trouts of age ranging between 1+ and 6+ years, for sizes ranging between 100 and 290 mm, were marked individually by visible implants in March 1998. The recapture rates observed varied from 19.5 to 74%, following the season considered. Growth rates showed a strong seasonal variability, validated by individual tagging experiments. Because of reproduction and rigorous temperatures experienced by trout during autumn and winter, growth rates observed were almost null and individuals >1+ lost weight during this period. In spite of theoretically non-optimal thermal conditions, growth occurred almost exclusively in spring. Poor growth rates observed during summer are not due to thermal factor which was theoretically optimal for growth in this season and could be attributed to the sexual maturation, to the saturation of the carrying capacity of physical habitat and to the strong intraspecific competition caused by i likely arrivals of 1+ and 2+ individuals emigrating from tributaries and ii reduction in "quantity and quality" of physical habitat at low-flow limiting accessibility and availability of energetically profitable prey. The role of growth in the dynamics of the brown trout population of the Neste d'Oueil River is discussed.

  20. Brown trout avoidance of metals in water characteristic of the Clark Fork River, Montana

    Science.gov (United States)

    Woodward, Daniel F.; Hansen, James A.; Bergman, Harold L.; Delonay, Aaron J.; Little, Edward E.

    1995-01-01

    The avoidance response of brown trout (Salmo trutta) to mixtures of cadmium, copper, lead, and zinc was determined in water simulating the Clark Fork River, Montana. Effects of acidification on the avoidance response were also evaluated. Tests were conducted in a cylindrical chamber that received reference water at one end and metal-contaminated water at the other; a distinct boundary formed at the center where the chamber drained. A 1 × mixture of the four metals (Cd, 1.1 μg/L; Cu, 12 μg/L; Pb, 3.2 μg/L; and Zn, 55 μg/L) that was representative of the ambient metals concentrations of the Clark Fork River resulted in avoidance by brown trout. Brown trout also avoided 0.5×, 2×, 4×, and 10× mixtures but not a 0.1 × mixture. A reduction in pH from 8.0 to either 7.0, 6.0, or 5.0 resulted in significant avoidance. Avoidance reactions to metals, similar to those observed in our laboratory experiments, may contribute to the depression of brown trout populations in the Clark Fork River.

  1. Animal welfare in brown trout farming: hematological results

    Directory of Open Access Journals (Sweden)

    G. Forneris

    2010-01-01

    Full Text Available The effect of stress resulting from fish farming has received considerable attention in this last period and fish welfare in aquaculture is a relevant topic, very important for the future of aquaculture (Watson et al., 2004; Klinger et al., 1996; Peres et al., 2004; Ron et al., 1995;Wagner et al., 1995;Watson et al., 1998. Brown trout farming is less developed then rainbow trout farming, but this kind of fish farming is increasing, mainly for fish conservation and restocking aquaculture.

  2. Stocking impact and migration pattern in an anadromous brown trout ( Salmo trutta ) complex: where have all the stocked spawning sea trout gone?

    DEFF Research Database (Denmark)

    Ruzzante, D.E.; Hansen, Michael Møller; Meldrup, Dorte;

    2004-01-01

    We examined polymorphism at seven microsatellite loci among sea trout (Salmo trutta) (n = 846) collected from three areas in the Limfjord (Denmark). We then assessed their potential population source by comparing, using a mixed stock analysis (MSA) Bayesian framework, their genetic composition...... to that of brown trout collected from 32 tributaries pooled into nine geographical regions (n = 3801) and two hatcheries (n = 222) used for stocking. For each of the three regional sea trout groups (western, central and eastern Limfjord, n = 91, n = 426, n = 329, respectively), MSA was conducted with (i) all...

  3. Testing for local adaptation in brown trout using reciprocal transplants

    Directory of Open Access Journals (Sweden)

    Stelkens Rike B

    2012-12-01

    Full Text Available Abstract Background Local adaptation can drive the divergence of populations but identification of the traits under selection remains a major challenge in evolutionary biology. Reciprocal transplant experiments are ideal tests of local adaptation, yet rarely used for higher vertebrates because of the mobility and potential invasiveness of non-native organisms. Here, we reciprocally transplanted 2500 brown trout (Salmo trutta embryos from five populations to investigate local adaptation in early life history traits. Embryos were bred in a full-factorial design and raised in natural riverbeds until emergence. Customized egg capsules were used to simulate the natural redd environment and allowed tracking the fate of every individual until retrieval. We predicted that 1 within sites, native populations would outperform non-natives, and 2 across sites, populations would show higher performance at ‘home’ compared to ‘away’ sites. Results There was no evidence for local adaptation but we found large differences in survival and hatching rates between sites, indicative of considerable variation in habitat quality. Survival was generally high across all populations (55% ± 3%, but ranged from 4% to 89% between sites. Average hatching rate was 25% ± 3% across populations ranging from 0% to 62% between sites. Conclusion This study provides rare empirical data on variation in early life history traits in a population network of a salmonid, and large-scale breeding and transplantation experiments like ours provide powerful tests for local adaptation. Despite the recently reported genetic and morphological differences between the populations in our study area, local adaptation at the embryo level is small, non-existent, or confined to ecological conditions that our experiment could not capture.

  4. 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.

  5. Interspecific interactions between brown trout and slimy sculpin in stream enclosures

    Science.gov (United States)

    Ruetz, C. R., III; Hurford, A.L.; Vondracek, B.

    2003-01-01

    We conducted a 30-d manipulative experiment in Valley Creek, Minnesota, to examine interspecific interactions between juvenile brown trout Salmo trutta and adult slimy sculpin Cottus cognatus. We measured the instantaneous growth of each species in the presence and absence of the other in 1-m2 enclosures. We tested single-species (three slimy sculpins/m2 or three brown trout/m2) and combined-species (three sculpins/m2 and three trout/m2) combinations in each of six riffles. We placed a clay tile in each enclosure to evaluate the effects of fish combinations on benthic macroinvertebrates. Growth of brown trout was unaffected by the presence of slimy sculpins (P = 0.647, power [to detect 50% increase in growth] = 0.92), whereas slimy sculpin growth was less in the presence of brown trout (P = 0.038). Densities of total benthic macroinvertebrates, Chironomidae, Trichoptera, and Physa did not differ among fish combinations (P > 0.3). However, densities of Gammarus pseudolimnaeus were significantly less in the presence of brown trout irrespective of the presence of slimy sculpins (P = 0.024), which could be a causal factor underlying the interaction between brown trout and slimy sculpins. We found asymmetrical competition between brown trout and slimy sculpins in stream enclosures, with brown trout being the superior competitor. Nevertheless, the size of enclosures may have biased our results, making it more likely to detect an effect of brown trout on slimy sculpins than vice versa.

  6. Heavy metal contamination and hepatic toxicological responses in brown trout (Salmo trutta) from the Kerguelen Islands

    OpenAIRE

    Jaffal, Ali; Betoulle, Stéphane; Biagianti-Risbourg, Sylvie; Terreau, Alexandre; Sanchez, Wilfried; Paris-Palacios, Séverine

    2015-01-01

    The Kerguelen Islands include various species of freshwater fish such as brown trout (Salmo trutta). These trout are among the most isolated from direct anthropogenic impact worldwide. This study was designed to analyse cadmium (Cd) and copper (Cu) concentrations in the liver of Kerguelen brown trout, and to assess the possible impacts of these metals on hepatic histopathology and oxidative stress parameters (superoxide dismutase and catalase activity and glutathione levels). Trout were caugh...

  7. Demographic changes following mechanical removal of exotic brown trout in an Intermountain West (USA), high-elevation stream

    Science.gov (United States)

    Saunders, W. Carl; Budy, Phaedra E.; Thiede, Gary P.

    2015-01-01

    Exotic species present a great threat to native fish conservation; however, eradicating exotics is expensive and often impractical. Mechanical removal can be ineffective for eradication, but nonetheless may increase management effectiveness by identifying portions of a watershed that are strong sources of exotics. We used mechanical removal to understand processes driving exotic brown trout (Salmo trutta) populations in the Logan River, Utah. Our goals were to: (i) evaluate the demographic response of brown trout to mechanical removal, (ii) identify sources of brown trout recruitment at a watershed scale and (iii) evaluate whether mechanical removal can reduce brown trout densities. We removed brown trout from 2 km of the Logan River (4174 fish), and 5.6 km of Right Hand Fork (RHF, 15,245 fish), a low-elevation tributary, using single-pass electrofishing. We compared fish abundance and size distributions prior to, and after 2 years of mechanical removal. In the Logan River, immigration to the removal reach and high natural variability in fish abundances limited the response to mechanical removal. In contrast, mechanical removal in RHF resulted in a strong recruitment pulse, shifting the size distribution towards smaller fish. These results suggest that, before removal, density-dependent mortality or emigration of juvenile fish stabilised adult populations and may have provided a source of juveniles to the main stem. Overall, in sites demonstrating strong density-dependent population regulation, or near sources of exotics, short-term mechanical removal has limited effects on brown trout populations but may help identify factors governing populations and inform large-scale management of exotic species.

  8. Regional prediction of basin-scale brown trout habitat suitability

    Science.gov (United States)

    Ceola, S.; Pugliese, A.

    2014-09-01

    In this study we propose a novel method for the estimation of ecological indices describing the habitat suitability of brown trout (Salmo trutta). Traditional hydrological tools are coupled with an innovative regional geostatistical technique, aiming at the prediction of the brown trout habitat suitability index where partial or totally ungauged conditions occur. Several methods for the assessment of ecological indices are already proposed in the scientific literature, but the possibility of exploiting a geostatistical prediction model, such as Topological Kriging, has never been investigated before. In order to develop a regional habitat suitability model we use the habitat suitability curve, obtained from measured data of brown trout adult individuals collected in several river basins across the USA. The Top-kriging prediction model is then employed to assess the spatial correlation between upstream and downstream habitat suitability indices. The study area is the Metauro River basin, located in the central part of Italy (Marche region), for which both water depth and streamflow data were collected. The present analysis focuses on discharge values corresponding to the 0.1-, 0.5-, 0.9-empirical quantiles derived from flow-duration curves available for seven gauging stations located within the study area, for which three different suitability indices (i.e. ψ10, ψ50 and ψ90) are evaluated. The results of this preliminary analysis are encouraging showing Nash-Sutcliffe efficiencies equal to 0.52, 0.65, and 0.69, respectively.

  9. An experimental field evaluation of winter carryover effects in semi-anadromous brown trout (Salmo trutta).

    Science.gov (United States)

    Midwood, Jonathan D; Larsen, Martin H; Boel, Mikkel; Aarestrup, Kim; Cooke, Steven J

    2015-11-01

    For semi-anadromous brown trout, the decision whether or not to smoltify and migrate to the sea is believed to be made at the end of the preceding summer in response to both local environmental conditions and individual physiological status. Stressors experienced during the fall may therefore influence their propensity to migrate as well as carry over into the winter resulting in mortality when fish face challenging environmental conditions. To evaluate this possibility, we artificially elevated cortisol levels in juvenile trout (via intracoelomic injection of cortisol in the fall) and used passive integrated transponder tags to compare their overwinter and spring survival, growth, and migration success relative to a control group. Results suggest that overwinter mortality is high for individuals in this population regardless of treatment. However, survival rates were 2.5 times lower for cortisol-treated fish and they experienced significantly greater loss in mass. In addition, less than half as many cortisol-treated individuals made it downstream to a stationary antenna over the winter and also during the spring migration compared to the control treatment. These results suggest that a fall stressor can reduce overwinter survival of juvenile brown trout, negatively impact growth of individuals that survive, and ultimately result in a reduction in the number of migratory trout. Carryover effects such as those documented here reveal the cryptic manner in which natural and anthropogenic stressors can influence fish populations. J. Exp. Zool. 323A: 645-654, 2015. © 2015 Wiley Periodicals, Inc. PMID:26381608

  10. 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.

  11. Interpopulation differences in expression of candidate genes for salinity tolerance in winter migrating anadromous brown trout (Salmo trutta L.

    Directory of Open Access Journals (Sweden)

    Thomsen Dennis S

    2008-01-01

    Full Text Available Abstract Background Winter migration of immature brown trout (Salmo trutta into freshwater rivers has been hypothesized to result from physiologically stressful combinations of high salinity and low temperature in the sea. Results We sampled brown trout from two Danish populations entering different saline conditions and quantified expression of the hsp70 and Na/K-ATPases α 1b genes following acclimation to freshwater and full-strength seawater at 2°C and 10°C. An interaction effect of low temperature and high salinity on expression of both hsp70 and Na/K-ATPase α 1b was found in trout from the river entering high saline conditions, while a temperature independent up-regulation of both genes in full-strength seawater was found for trout entering marine conditions with lower salinities. Conclusion Overall our results support the hypothesis that physiologically stressful conditions in the sea drive sea-run brown trout into freshwater rivers in winter. However, our results also demonstrate intra-specific differences in expression of important stress and osmoregulative genes most likely reflecting adaptive differences between trout populations on a regional scale, thus strongly suggesting local adaptations driven by the local marine environment.

  12. 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.

  13. Diurnal stream habitat use of juvenile Atlantic salmon, brown trout and rainbow trout in winter

    Science.gov (United States)

    Johnson, J.H.; Douglass, K.A.

    2009-01-01

    The diurnal winter habitat of three species of juvenile salmonids was examined in a tributary of Skaneateles Lake, NY to compare habitat differences among species and to determine if species/age classes were selecting specific habitats. A total of 792 observations were made on the depth, velocity, substrate and cover (amount and type) used by sympatric subyearling Atlantic salmon, subyearling brown trout and subyearling and yearling rainbow trout. Subyearling Atlantic salmon occurred in shallower areas with faster velocities and less cover than the other salmonid groups. Subyearling salmon was also the only group associated with substrate of a size larger than the average size substrate in the study reach during both winters. Subyearling brown trout exhibited a preference for vegetative cover. Compared with available habitat, yearling rainbow trout were the most selective in their habitat use. All salmonid groups were associated with more substrate cover in 2002 under high flow conditions. Differences in the winter habitat use of these salmonid groups have important management implications in terms of both habitat protection and habitat enhancement.

  14. BIOMASS AND DENSITY OF BROWN AND RAINBOW TROUT IN NEW MEXICO STREAMS

    OpenAIRE

    Srečko Lainer

    1995-01-01

    Mean stream numerical density of the brown trout (Salmo trutta m. fario Linnaeus, 1758) and the rainbow trout (Onchorhynchus mykiss Walbaum, 1792) was 0.090 fish/m2 of which brown trout averaged 69% (72% in total biomass) in 15 high-elevation New Mexico streams (1,661-2,560 m above sea level). Total trout density varied from 0.008/m2 in 1988 and 1989. Mean trout density ranged between 0.023-0.121 fish/m2 at site s open to public fishing. Considerably higher densities (0.142-0.409 fish/m2) wer...

  15. Effects of water temperature and fish size on predation vulnerability of juvenile humpback chub to rainbow trout and brown trout

    Science.gov (United States)

    Ward, David L.; Morton-Starner, Rylan

    2015-01-01

    Predation on juvenile native fish by introduced Rainbow Trout and Brown Trout is considered a significant threat to the persistence of endangered Humpback Chub Gila cypha in the Colorado River in the Grand Canyon. Diet studies of Rainbow Trout and Brown Trout in Glen and Grand canyons indicate that these species do eat native fish, but impacts are difficult to assess because predation vulnerability is highly variable, depending on prey size, predator size, and the water temperatures under which the predation interactions take place. We conducted laboratory experiments to evaluate how short-term predation vulnerability of juvenile native fish changes in response to fish size and water temperature using captivity-reared Humpback Chub, Bonytail, and Roundtail Chub. Juvenile chub 45–90 mm total length (TL) were exposed to adult Rainbow and Brown trouts at 10, 15, and 20°C to measure predation vulnerability as a function of water temperature and fish size. A 1°C increase in water temperature decreased short-term predation vulnerability of Humpback Chub to Rainbow Trout by about 5%, although the relationship is not linear. Brown Trout were highly piscivorous in the laboratory at any size > 220 mm TL and at all water temperatures we tested. Understanding the effects of predation by trout on endangered Humpback Chub is critical in evaluating management options aimed at preserving native fishes in Grand Canyon National Park.

  16. Reproductive isolation and genetic differentiation of ferox trout from sympatric brown trout in Loch Aweand Loch Laggan, Scotland

    OpenAIRE

    Duguid, A.; Prodohl, Paulo; Ferguson, A.

    2006-01-01

    Molecular marker studies reported here, involving allozymes, mitochondrial DNA and microsatellites, demonstrate that ferox brown trout Salmo trutta in Lochs Awe and Laggan, Scotland, are reproductively isolated and genetically distinct from co-occurring brown trout. Ferox were shown to spawn primarily, and possibly solely, in a single large river in each lake system making them particularly vulnerable to environmental changes. Although a low level of introgression seems to have occurred with ...

  17. Daytime habitat selection for juvenile parr brown trout (Salmo trutta) in small lowland streams

    DEFF Research Database (Denmark)

    Conallin, J.; Boegh, E.; Olsen, M.;

    2014-01-01

    Physical habitat is important in determining the carrying capacity of juvenile brown trout, and within freshwater management. Summer daytime physical habitat selection for the parr lifestage (7-20 cm) juvenile brown trout (Salmo trutta) was assessed in 6 small lowland streams. Habitat preference...

  18. Pre-migratory differentiation of wild brown trout into migrant and resident individuals

    DEFF Research Database (Denmark)

    Nielsen, C.; Aarestrup, Kim; Norum, U.;

    2003-01-01

    In February to March, wild brown trout Salmo trutta were captured by electrofishing in a natural watercourse (tributaries of the River Lille Aa, Denmark), individually tagged (Passive Integrated Transponders), and released. Representatives of the tagged brown trout were recaptured on the release...

  19. 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...

  20. Survival of intragravel stages of brown trout (Salmo trutta L.) in Teesdale

    OpenAIRE

    Ottaway, E.M.; Clarke, A.

    1981-01-01

    A study has been undertaken on several streams in Teesdale (UK)in order to examine survival rates of intragravel stages of brown trout and the factors influencing survival. Although all the becks contained brown trout spawning areas, some were utilised by more spawning trout than others. The best spawning sites as judged by this criterion were Thorsgill and Great Eggleshope becks where the research effort was therefore concentrated. There were two different spawning areas in Eggleshope, namel...

  1. Genetic characterization of broodstock brown trout from Bled fish-farm, Slovenia

    OpenAIRE

    Marić, Saša; Simonović, Predrag; Razpet, Andrej

    2010-01-01

    Background and Purpose: Due to environmental and economic concerns, Bled fish-farm is interested in establishing broodstocks of native brown trout (Salmo trutta L.). Progeny would be reared and released into rivers managed by the Fishing Club Bled. In this study was performed genetic characterization of broodstock from Bled fish-farm in order to assess hybridization of native brown trout of Danubian phylogeographic lineage with trout of the allochtonous Atlantic lineage. Material and Meth...

  2. MONITORING OF BROWN TROUT (SALMO TRUTTA GROWTH IN INDUSTRIAL CONDITIONS OF THE FISH FARM «ISHKHAN»

    Directory of Open Access Journals (Sweden)

    A. Mruk

    2013-03-01

    Full Text Available The paper contains results of brown trout (Salmo trutta growing in industrial conditions of the fish farm “Ishkhan” during three years. It was found that linear growth and weight accumulation of fish after reaching the one-year age increased and were superior in comparison with natural populations.

  3. The role of environmental transfer of macro-elements in the Brown trout Salmo trutta

    OpenAIRE

    Baszyński, Jędrzej; Kamiński, Piotr; Koim-Puchowska, Beata

    2015-01-01

    In natural habitat of river Słupia researchers observe the fall condition among Brown trouts and their morbidity on ulcerative dermal necrosis. Trout's shape is strictly connected with elemental economy. In recent study we analyse the macroelements economy (Na, Mg, K, Ca, P) in trout's organism on different growth stages: young and adult individuals, inside trout's organs (muscles, gills, liver, fins), in periods of 2006-2007 and 2011-2012. We analyse the concentrations of chosen chemical ele...

  4. Patterns of natural mortality in stream-living brown trout (Salmo trutta)

    Science.gov (United States)

    Lobon-Cervia, J.; Budy, P.; Mortensen, E.

    2012-01-01

    We tested the hypothesis that lifetime mortality patterns and their corresponding rates and causal factors differ among populations of stream-living salmonids. To this end, we examined the lifetime mortality patterns of several successive cohorts of two stream-living brown trout (Salmo trutta) populations in Spain and Denmark. In the southern population, we observed a consistent two-phase pattern, in which mortality was negligible during the first half of the lifetime and severe during the rest of the lifetime. In contrast, the northern population demonstrated a three-phase pattern with an earlier phase varying from negligible to severe, followed by a second stage of weak mortality, and lastly by a third life stage of severe mortality. Despite substantial differences in the mortality patterns between the two populations, the combined effect of recruitment (as a proxy of the density-dependent processes occurring during the lifetime) and mean body mass (as a proxy of growth experienced by individuals in a given cohort) explained c. 89% of the total lifetime mortality rates across cohorts and populations. A comparison with other published data on populations of stream-living brown trout within its native range highlighted lifetime mortality patterns of one, two, three and four phases, but also suggested that common patterns may occur in populations that experience similar individual growth and population density. ?? 2011 Blackwell Publishing Ltd.

  5. Age and Growth of Brown Trout (Salmo trutta in Six Rivers of the Southern Part of Caspian Basin

    Directory of Open Access Journals (Sweden)

    Azarmidokht Kheyrandish

    2010-01-01

    Full Text Available Problem statement: Because of dramatic declines in stocks of brown trout in southern part of Caspian basin, the population's structure of brown trout (Salmo trutta in several rivers were studied to provide data for conservation programs. Approach: The structure of the populations in the six rivers of the southern part of Caspian basin including: Keliyare, Khojirood, Lar, Shirinrood, Rig cheshme and Pajimiyane, were studied. Results: Five age classes, ranged from 0+-4+ years, were determined. The most frequent age classes belong to 1+ and 2+. The length ranged from 78-305 mm and weight ranged from 3.6-390 g. Also, the condition factor ranged from 0.58-1.47. The highest and lowest length, weight and condition factor were observed in Lar and Rig cheshme, respectively. In 5 out of 6 rivers, females were dominant over males. The highest and lowest female: Male ratios were observed in Pajimiane (6.75:1 and Khojirood (0.8:1, respectively. Significant relationships were found between total length of brown trout with depth (r = 0.6, pConclusion: According to our knowledge, this is the first report of brown trout from Kelyare and Khojirood rivers. Since size of populations in studied areas are small and majority of these rivers located in low protected locations, it is essential to apply serious measures to protect these vulnerable habitats.

  6. Metals-contaminated benthic invertebrates in the Clark Fork River, Montana: Effects on age-0 brown trout and rainbow trout

    Science.gov (United States)

    Woodward, Daniel F.; Farag, Aïda M.; Bergman, Harold L.; Delonay, Aaron J.; Little, Edward E.; Smiths, Charlie E.; Barrows, Frederic T.

    1995-01-01

    Benthic organisms in the upper Clark Fork River have recently been implicated as a dietary source of metals that may be a chronic problem for young-of-the-year rainbow trout (Oncorhynchus mykiss). In this present study, early life stage brown trout (Salmo trutta) and rainbow trout were exposed for 88 d to simulated Clark Fork River water and a diet of benthic invertebrates collected from the river. These exposures resulted in reduced growth and elevated levels of metals in the whole body of both species. Concentrations of As, Cd, Cu, and Pb increased in whole brown trout; in rainbow trout, As and Cd increased in whole fish, and As also increased in liver. Brown trout on the metals-contaminated diets exhibited constipation, gut impaction, increased cell membrane damage (lipid peroxidation), decreased digestive enzyme production (zymogen), and a sloughing of intestinal mucosal epithelial cells. Rainbow trout fed the contaminated diets exhibited constipation and reduced feeding activity. We believe that the reduced standing crop of trout in the Clark Fork River results partly from chronic effects of metals contamination in benthic invertebrates that are important as food for young-of-the-year fish.

  7. Relying on fin erosion to identify hatchery-reared brown trout in a Tennessee river

    Science.gov (United States)

    Meerbeek, Jonathan R.; Bettoli, Phillip William

    2012-01-01

    Hatchery-induced fin erosion can be used to identify recently stocked catchable-size brown trout Salmo trutta during annual surveys to qualitatively estimate contributions to a fishery. However, little is known about the longevity of this mark and its effectiveness as a short-term (≤ 1 year) mass-marking technique. We evaluated hatchery-induced pectoral fin erosion as a mass-marking technique for short-term stocking evaluations by stocking microtagged brown trout in a tailwater and repeatedly sampling those fish to observe and measure their pectoral fins. At Dale Hollow National Fish Hatchery, 99.1% (228 of 230) of microtagged brown trout in outdoor concrete raceways had eroded pectoral fins 1 d prior to stocking. Between 34 and 68 microtagged and 26-35 wild brown trout were collected during eight subsequent electrofishing samples. In a blind test based on visual examination of pectoral fins at up to 322 d poststocking, one observer correctly identified 91.7% to 100.0% (mean of 96.9%) of microtagged brown trout prior to checking for microtags. In the laboratory, pectoral fin length and width measurements were recorded to statistically compare the fin measurements of wild and microtagged hatchery brown trout. With only one exception, all pectoral fin measurements on each date averaged significantly larger for wild trout than for microtagged brown trout. Based on the number of pectoral fin measurements falling below 95% prediction intervals, 93.7% (148 of 158) of microtagged trout were correctly identified as hatchery fish based on regression models up to 160 d poststocking. Only 72.2% (70 of 97) of microtagged trout were identified correctly after 160 d based on pectoral fin measurements and the regression models. We concluded that visual examination of pectoral fin erosion was a very effective way to identify stocked brown trout for up to 322 d poststocking.

  8. BIOMASS AND DENSITY OF BROWN AND RAINBOW TROUT IN NEW MEXICO STREAMS

    Directory of Open Access Journals (Sweden)

    Srečko Lainer

    1995-03-01

    Full Text Available Mean stream numerical density of the brown trout (Salmo trutta m. fario Linnaeus, 1758 and the rainbow trout (Onchorhynchus mykiss Walbaum, 1792 was 0.090 fish/m2 of which brown trout averaged 69% (72% in total biomass in 15 high-elevation New Mexico streams (1,661-2,560 m above sea level. Total trout density varied from 0.008/m2 in 1988 and 1989. Mean trout density ranged between 0.023-0.121 fish/m2 at site s open to public fishing. Considerably higher densities (0.142-0.409 fish/m2 were observed at sites closed for fishing. In the seven selected streams shared by both species, brown trout density exceeded rainbow trout density except at the two sites closed to fishing. Brown trout were stocked only as fingerlings (average 7,000 fish/stream/year while rainbow trout were stocked only in harvestable sizes (11,000 fish/stream/year. Reported total trout yield rates exceeded the total number of fish estimated to be in the stream by 1.01 to 11.63 in most small streams open to fishing. The proportional stock density (PSD ranged between O and 50 percent. Streams with low to moderate intensities of fishing had the highest PSD.

  9. Identification of differentially expressed genes of brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) in response to Tetracapsuloides bryosalmonae (Myxozoa)

    OpenAIRE

    Kumar, Gokhlesh; Abd-Elfattah, Ahmed; El-Matbouli, Mansour

    2015-01-01

    Tetracapsuloides bryosalmonae Canning et al., 1999 (Myxozoa) is the causative agent of proliferative kidney disease in various species of salmonids in Europe and North America. We have shown previously that the development and distribution of the European strain of T. bryosalmonae differs in the kidney of brown trout (Salmo trutta) Linnaeus, 1758 and rainbow trout (Oncorhynchus mykiss) Walbaum, 1792, and that intra-luminal sporogonic stages were found in brown trout but not in rainbow trout. ...

  10. 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...

  11. Interpopulation differences in expression of candidate genes for salinity tolerance in winter migrating anadromous brown trout ( Salmo trutta L.)

    DEFF Research Database (Denmark)

    Larsen, Peter Foged; Eg Nielsen, Einar; Koed, Anders;

    2008-01-01

    saline conditions and quantified expression of the hsp70 and Na/K-ATPases alpha 1b genes following acclimation to freshwater and full-strength seawater at 2 degrees C and 10 degrees C. An interaction effect of low temperature and high salinity on expression of both hsp70 and Na/K-ATPase alpha 1b...... was found in trout from the river entering high saline conditions, while a temperature independent up-regulation of both genes in full-strength seawater was found for trout entering marine conditions with lower salinities. Conclusion: Overall our results support the hypothesis that physiologically stressful...... conditions in the sea drive sea-run brown trout into freshwater rivers in winter. However, our results also demonstrate intra-specific differences in expression of important stress and osmoregulative genes most likely reflecting adaptive differences between trout populations on a regional scale, thus...

  12. Eggs Incubation, Early Development and growth in Frys of Brown Trout (Salmo trutta macrostigma) and Black Sea Trout (Salmo trutta labrax)

    OpenAIRE

    Ahmet ALP; Erer, Mesut; KAMALAK, Adem

    2010-01-01

    Some of the embryonic development stages and growth of the frys of brown trout (Salmo trutta macrostigma) and Black Sea trout (Salmo trutta labrax) were examined. The first eye pigmentation in the brown trout eggs were realised on the 35 days (244 day-degree) at 7.23°C and 31 days (260 day-degree) at 8.21°C post fertilisation. First eye pigmentation of the Black Sea trout eggs were seen on day 25 (215 day-degree) at 8.21°C. Brown trout larvae were hatched on day 56 (387 day-degree) at 7.23°C ...

  13. Micro-scale distribution of brown trout: an opportunity for kin selection?

    DEFF Research Database (Denmark)

    Carlsson, J.; Carlsson, J.E.L.

    2002-01-01

    Fourteen microsatellite loci were used to analyse the degree of relatedness between and within cohorts of stream-living brown trout (Salmo trutta L.). Differences in degree of relatedness were found between cohorts with mature and older having the highest intracohort relatedness. The higher genetic...... relatedness among the mature and older trout is interpreted as indications of clustering of related mature and older trout prior to spawning in the vicinity of spawning grounds. Young-of-the-year trout showed a lower degree of association with related trout of the same cohort than did mature and older trout....... It is argued that the clustering of mature and older trout may facilitate kin selection and that the low degree of association among related young-of-the-year trout could be explained by juvenile fish avoiding competition for territories with related individuals...

  14. An investigation of the recaptures rates for tagged brown trout stocked into the River Ribble

    OpenAIRE

    Clifton-Dey , D.; Walsingham, M.

    1996-01-01

    The angling season for non-migratory brown trout, in the Environment Agency (EA) North West Region, runs from March 15th to September 30th. Each year, large numbers of farm reared brown trout are stocked into the rivers of the North West Region's Central Area. In 1994, approximately 20,000 brown trout were introduced into the River systems of the Lune, Wyre and Ribble by local angling clubs and fishery owners. Most of these fish were stocked at a length greater than that defined by local byel...

  15. Parasitofauna study of the brown trout, Salmo trutta (Pisces, Teleostei from Corsica (Mediterranean island rivers

    Directory of Open Access Journals (Sweden)

    Quilichini Y.

    2007-09-01

    Full Text Available Corsica is a mediterranean island characterised by a great number of rivers. Salmonides are the main fishes which populate these rivers. Very appreciated by fishermen, Salmonides are represented by three species in the insular hydrographical network, among which an autochthonous species, the brown trout (Salmo trutta. In the present work, we have analysed the parasitofauna of this species. According to our knowledge, this research has never been carried out in Corsica. In a first step, we drew up an inventory of the parasites found in this freshwater fish. In a second step, we studied the differences which appeared in the composition of parasite communities of this species.

  16. Fate of Tetracapsuloides bryosalmonae (Myxozoa) after infection of brown trout Salmo trutta and rainbow trout Oncorhynchus mykiss

    OpenAIRE

    Kumar, Gokhlesh; Abd-Elfattah, Ahmed; Saleh, Mona; El-Matbouli, Mansour

    2013-01-01

    Tetracapsuloides bryosalmonae (Myxozoa) is the causative agent of proliferative kidney disease in salmonids. We assessed differences in intensity of T. bryosalmonae infection between brown trout Salmo trutta and rainbow trout Oncorhynchus mykiss from the clinical phase of infection onwards. Specific pathogen-free fish were exposed to T. bryosalmonae spores under controlled laboratory conditions and sampled at 6, 8, 10, 12, 14, and 17 wk post exposure (wpe), and the transmission of T. bryosalm...

  17. Otter ( Lutra lutra ) predation on stocked brown trout ( Salmo trutta ) in two Danish lowland rivers

    DEFF Research Database (Denmark)

    Jacobsen, Lene

    2005-01-01

    This study aimed to evaluate otter predation on stocked trout. Large hatchery-reared trout (16-30 cm) were stocked into two Danish rivers with different fish populations. Otter diet before and after trout stocking was determined by analysing 685 spraints, collected regularly during the 35-day study...... period. Fish composition in the rivers before stocking was assessed by electrofishing. In River Trend, a typical trout river, the proportion of trout in the otter diet increased from 8% before stocking to 33% a few days after stocking. Moreover, trout lengths in the diet changed significantly towards the...... lengths of stocked trout, indicating that newly stocked trout were preferred to wild trout. In River Skals, dominated by cyprinids, there was no change in otter diet after stocking of hatchery trout, i.e., these were ignored by otter. Otter predation should be taken into account together with fish and...

  18. Historical demography of brown trout (Salmo trutta) in the Adriatic drainage including the putative S. letnica endemic to Lake Ohrid.

    Science.gov (United States)

    Susnik, Simona; Snoj, Ales; Wilson, Iain F; Mrdak, Danilo; Weiss, Steven

    2007-07-01

    We explore the historical demography of the Adriatic lineage of brown trout and more explicitly the colonization and phylogenetic placement of Ohrid trout, based on variation at 12 microsatellite loci and the mtDNA control region. All Adriatic basin haplotypes reside in derived positions in a network that represents the entire lineage. The central presumably most ancestral haplotype in this network is restricted to the Iberian Peninsula, where it is very common, supporting a Western Mediterranean origin for the lineage. The expansion statistic R2, Bayesian based estimates of demographic parameters, and star-like genealogies support expansions on several geographic scales, whereas application of pairwise mismatch analysis was somewhat ambiguous. The estimated time since expansion (155,000 years ago) for the Adriatic lineage was supported by a narrow confidence interval compared to previous studies. Based on microsatellite and mtDNA sequence variation, the endemic Ohrid trout represents a monophyletic lineage isolated from other Adriatic basin populations, but nonetheless most likely evolving from within the Adriatic lineage of brown trout. Our results do not support the existence of population structuring within Lake Ohrid, even though samples included two putative intra-lacustrine forms. In the interests of protecting the unique biodiversity of this ancient ecosystem, we recommend retaining the taxonomic epithet Salmo letnica for the endemic Ohrid trout. PMID:17046289

  19. Optimal flow for brown trout: Habitat - prey optimization.

    Science.gov (United States)

    Fornaroli, Riccardo; Cabrini, Riccardo; Sartori, Laura; Marazzi, Francesca; Canobbio, Sergio; Mezzanotte, Valeria

    2016-10-01

    The correct definition of ecosystem needs is essential in order to guide policy and management strategies to optimize the increasing use of freshwater by human activities. Commonly, the assessment of the optimal or minimum flow rates needed to preserve ecosystem functionality has been done by habitat-based models that define a relationship between in-stream flow and habitat availability for various species of fish. We propose a new approach for the identification of optimal flows using the limiting factor approach and the evaluation of basic ecological relationships, considering the appropriate spatial scale for different organisms. We developed density-environment relationships for three different life stages of brown trout that show the limiting effects of hydromorphological variables at habitat scale. In our analyses, we found that the factors limiting the densities of trout were water velocity, substrate characteristics and refugia availability. For all the life stages, the selected models considered simultaneously two variables and implied that higher velocities provided a less suitable habitat, regardless of other physical characteristics and with different patterns. We used these relationships within habitat based models in order to select a range of flows that preserve most of the physical habitat for all the life stages. We also estimated the effect of varying discharge flows on macroinvertebrate biomass and used the obtained results to identify an optimal flow maximizing habitat and prey availability. PMID:27320735

  20. Marine migration and habitat use of anadromous brown trout Salmo trutta

    DEFF Research Database (Denmark)

    Eldøy, Sindre Håvarstein; Davidsen, Jan Grimsrud; Thorstad, Eva Bonsak;

    2015-01-01

    The biology and ecology of anadromous brown trout (Salmo trutta) at sea is poorly understood. This study provided information on spatial and temporal distribution of sea trout in the ocean. The behaviour of 115 individuals (veteran migrants, 270–700 mm) was tracked by using acoustic telemetry in a...

  1. Diel foraging and shelter use of large juvenile brown trout (Salmo trutta) under food satiation

    OpenAIRE

    Conallin J.; Jyde M.; Filrup K.; Pedersen S.

    2012-01-01

    The diel partitioning of juvenile brown trout Salmo trutta foraging behaviour is controlled by a number of factors including predation risk, competition, temperature and food availability. The present study uses PIT-tagging and visual observation to asses the use of shelter and foraging behaviour of Danish wild juvenile brown trout (13.5–15.6 cm). The experiment was conducted in a fluvarium and the fish were fed to satiation. It was hypothesised that food satiation w...

  2. Have Introduced Brown Trout (Salmo Trutta) Affected Native Aquatic Vertebrates in Western United States Streams?

    OpenAIRE

    Burbank, Nora K.

    2011-01-01

    The introduction of exotic species is one of the greatest threats to freshwater biodiversity. Brown trout are native to Eurasia, but have been introduced to much of the rest of the world, including the United States. In other parts of their introduced range, brown trout have caused substantial negative effects to native species‟ abundances and distributions, and have altered the structure of some aquatic communities. In the United States, studies of some streams and watersheds have shown that...

  3. Winter feeding, growth and condition of brown trout Salmo trutta in a groundwater-dominated stream

    Science.gov (United States)

    French, William E.; Vondracek, Bruce C.; Ferrington, Leonard C., Jr.; Finlay, Jacques C.; Dieterman, Douglas J.

    2014-01-01

    Winter can be a stressful period for stream-dwelling salmonid populations, often resulting in reduced growth and survival. Stream water temperatures have been identified as a primary mechanism driving reductions in fitness during winter. However, groundwater inputs can moderate water temperature and may reduce winter severity. Additionally, seasonal reductions in prey availability may contribute to decreased growth and survival, although few studies have examined food webs supporting salmonids under winter conditions. This study employed diet, stable isotope, and mark-recapture techniques to examine winter (November through March) feeding, growth, and condition of brown troutSalmo trutta in a groundwater-dominated stream (Badger Creek, Minnesota, USA). Growth was greater for fish ≤ 150 mm (mean = 4.1 mg g−1 day−1) than for those 151–276 mm (mean = 1.0 mg g−1 day−1) during the winter season. Overall condition from early winter to late winter did not vary for fish ≤150 mm (mean relative weight (Wr) = 89.5) and increased for those 151–276 mm (mean Wr = 85.8 early and 89.4 late). Although composition varied both temporally and by individual, brown trout diets were dominated by aquatic invertebrates, primarily Amphipods, Dipterans, and Trichopterans. Stable isotope analysis supported the observations of the dominant prey taxa in stomach contents and indicated the winter food web was supported by a combination of allochthonous inputs and aquatic macrophytes. Brown trout in Badger Creek likely benefited from the thermal regime and increased prey abundance present in this groundwater-dominated stream during winter.

  4. Ontogenetic shifts in terrestrial reliance of stream-dwelling brown trout

    Directory of Open Access Journals (Sweden)

    Javier Sánchez-Hernández

    2016-07-01

    Full Text Available This study focuses on terrestrial reliance of brown trout (Salmo trutta and compared it to the potential prey available (macrozoobenthos and drifting invertebrates in three temperate rivers (Galicia, NW Spain, with special emphasis on variations in terrestrial energy intake through the ontogeny of brown trout. Additionally, we paid particular attention to individual variation of terrestrial resource use within and between age classes. Prey items were grouped in four categories: i aquatic invertebrates; ii imagoes of aquatic invertebrates; iii terrestrial invertebrates; and iv fish prey. Next, energy composition was measured according to dry weight-energy equations for each individual in line with above-mentioned prey categories. Our findings illustrate that terrestrial invertebrates appeared to be scarce in the environment, whereas aquatic food resources were rather abundant and accessible. The use of terrestrial invertebrates tended to increase with age, but with a high degree of inter-individual variation in resource use. In fact, the individual reliance of brown trout on terrestrial invertebrates may vary considerably (between 0% and 76.9%. Besides, the frequency of terrestrial foragers, i.e., individuals with terrestrial invertebrates in their stomachs, increased with age, except in one population which had the maximum value in the age-2 class. The acquisition of terrestrial invertebrates thus appears to be a process strongly dependent upon the actual food availability in the environment, but with a high degree of individual variance in resource use within the same age class. Finally, we discuss that terrestrial invertebrates may largely contribute to cover the energy intake of the species, highlighting the interface between terrestrial and aquatic ecosystems, and thereby the importance of riparian canopy cover as a key factor for food supply of stream-dwelling salmonids species.

  5. Diel foraging and shelter use of large juvenile brown trout (Salmo trutta) under food satiation

    DEFF Research Database (Denmark)

    Conallin, J.; Jyde, M.; Filrup, K.;

    2012-01-01

    The diel partitioning of juvenile brown trout Salmo trutta foraging behaviour is controlled by a number of factors including predation risk, competition, temperature and food availability. The present study uses PIT-tagging and visual observation to asses the use of shelter and foraging behaviour...... of Danish wild juvenile brown trout (13.5-15.6 cm). The experiment was conducted in a fluvarium and the fish were fed to satiation. It was hypothesised that food satiation would promote nocturnal foraging and increase daytime shelter use. Our results showed a significant difference in diel shelter...... trout only feed during the day to the extent needed to sustain growth...

  6. Self-feeding ability of farm-reared native Mediterranean and Atlantic brown trout juveniles into artificial system

    OpenAIRE

    Mitjana Nerín, Olga María; Alabart Alvarez, José Luis; Clavero, J.L.; Blasco Martínez, José María; Josa, A; Espinosa, E.

    2011-01-01

    Stocked brown trouts have reduced ability to obtain food resulting in reduced survival rates. Adaptation to natural environments of farm-reared fishes becomes crucial early after restocking. The aim of this work was to evaluate the self-feeding ability of different strains of juvenile brown trout placed at different densities and in presence or absence of predators. Three different strains of juvenile brown trout were placed for 3 weeks into seminatural ponds at two stocking de...

  7. New Mitochondrial DNA Haplotype of Brown Trout Salmo trutta l. from Crni Timok Drainage Area in Serbia

    OpenAIRE

    Toši63; Nikoli63; Simonovi63; Škraba, Dubravka; Mrdak, Danilo

    2014-01-01

    Brown trout Salmo trutta wild stocks sustain a remarkable angling and hatchery-reared fish stocking pressure in waters of Serbia, where four drainage-specific and indigenous mitochondrial DNA haplotypes were reported for the drainage area of the Danube River basin. One of these mitochondrial DNA haplotypes, Da23b, was exclusive for brown trout in headwaters of the Crni Timok River (Grand Timok River system, Eastern Serbia). After its discovery in 2003, brown trout stocking was completely ...

  8. Juvenile competitive bottleneck in the production of brown trout in hydroelectric reservoirs due to intraspecific habitat segregation

    International Nuclear Information System (INIS)

    Resource utilization and growth of brown trout were studied in four deep (mean depths 16.2 - 37.5 m) Norwegian hydroelectric reservoirs by benthic and pelagic gillnet sampling. In all the reservoirs supplementary stockings are carried out. The brown trout were spatially segregated according to size as the habitat use of small individuals (< 180-220 mm) was completely restricted to benthic habitats, whereas larger individuals mainly utilized the upper strata of pelagic waters. It is argued that the pelagic habitat is the more rewarding, and that small-sized brown trout are forced into the less favourable benthic habitat through social interactions with larger specimens. This is supported by an increase in growth of brown trout from their third to fifth year of life, which seems to be related to the shift from benthic to pelagic behaviour. It is also argued that the conditions for small-sized brown trout may be a bottleneck in the capacity to produce brown trout in hydroelectric reservoirs with limited benthic feeding conditions, despite ample access to food in pelagic habitats. When evaluating the possibility of increasing the yield of brown trout through supplementary stockings, it is therefore important to consider food and growth conditions for all age and size groups of brown trout. In reservoirs with poor benthic feeding conditions it may be necessary to stock with brown trout of sizes that are large enough to utilize pelagic habitat, to avoid the limiting benthic living stage. (Author)

  9. Telomere dynamics in wild brown trout: effects of compensatory growth and early growth investment.

    Science.gov (United States)

    Näslund, Joacim; Pauliny, Angela; Blomqvist, Donald; Johnsson, Jörgen I

    2015-04-01

    After a period of food deprivation, animals often respond with a period of faster than normal growth. Such responses have been suggested to result in decreased chromosomal maintenance, which in turn may affect the future fitness of an individual. Here, we present a field experiment in which a food deprivation period of 24 days was enforced on fish from a natural population of juvenile brown trout (Salmo trutta) at the start of the high-growth season in spring. The growth of the food-deprived fish and a non-deprived control group was then monitored in the wild during 1 year. Fin tissue samples were taken at the start of the experiment and 1 year after food deprivation to monitor the telomere dynamics, using reduced telomere length as an indicator of maintenance cost. The food-deprived fish showed partial compensatory growth in both mass and length relative to the control group. However, we found no treatment effects on telomere dynamics, suggesting that growth-compensating brown trout juveniles are able to maintain their telomeres during their second year in the stream. However, body size at the start of the experiment, reflecting growth rate during their first year of life, was negatively correlated with change in telomere length over the following year. This result raises the possibility that rapid growth early in life induces delayed costs in cellular maintenance. PMID:25698140

  10. Range and movement of resident holdover and hatchery brown trout tagged with radio transmitters in the Farmington River, Connecticut

    Science.gov (United States)

    Popoff, N.D.; Neumann, Robert M.

    2005-01-01

    The 5.8-km West Branch Farmington River Trout Management Area (TMA) is one of Connecticut's premier catch-and-release fisheries for brown trout Salmo trutta. However, little is known about the behavior of brown trout in this system and to what extent brown trout emigrate from the TMA. The objectives of this study were to determine the movement, range, and emigration of resident holdover and newly stocked brown trout tagged with radio transmitters in the TMA. Transmitters were implanted into 22 first-year (mean total length = 314 mm) and 25 second-year (mean total length = 432 mm) holdover brown trout. Twenty catchable-size (mean total length = 290 mm) brown trout were also implanted with transmitters and released into the TMA. The mean range (distance between the extreme upstream and downstream locations) was greater for second-year holdover brown trout than for first-year holdover brown trout, and it was greater in fall than in winter. The movement (distance moved between successive locations) of holdover brown trout was greater in fall than in winter. Movement of first-year holdover brown trout was significantly related to discharge, water temperature, and the number of days between successive locations. Newly stocked brown trout exhibited the two largest ranges (5.3 and 4.7 km). The range of newly stocked brown trout was not different between seasons, but movement was greater in spring than in summer. Through 16 weeks poststocking, there was no discernable difference in the percentage of stocked brown trout dispersing in a predominantly upstream or downstream direction. Mean dispersal distances from the stocking location were 0.5 and 0.9 km at 2 and 12 weeks poststocking, respectively. Movement of newly stocked brown trout was positively related to discharge and negatively related to water temperature. A known 6% (4 of 67) of the tagged brown trout emigrated from the TMA, but up to 21% (14 of 67) of tagged fish could have left the study area if all missing fish

  11. The geographic isolation impact on evolution of some morpho-physiological features in the brown trout (Salmo trutta fario Linnaeus

    Directory of Open Access Journals (Sweden)

    Ioan Bud

    2009-01-01

    Full Text Available The researches made by our team have in view the bio-morphometric study of some brown trout populations. We aimed, on the one hand, to see the geographic and reproductive isolation impact and, on the other hand to highlight the environmental factors’ influence on morphological features in this species. The researches have in view three aquatic basins, known as sanctuaries of the brown trout,respectively Someş, Criş and Arieş. For the morphometric study were taken in calculus 14 bodydimensions, which allow to analyze on scientific basis the intra-specific variability degree, to which we add also the estimation of some meristic features (number of red or black spots. All data were statistically processed using modern methods thereby the interpretation errors to be more reduced. The results are presented in tables included in our paper.

  12. Interpopulation differences in expression of candidate genes for salinity tolerance in winter migrating anadromous brown trout (Salmo trutta L.)

    OpenAIRE

    Thomsen Dennis S; Koed Anders; Nielsen Einar E; Larsen Peter F; Olsvik Pål A; Loeschcke Volker

    2008-01-01

    Abstract Background Winter migration of immature brown trout (Salmo trutta) into freshwater rivers has been hypothesized to result from physiologically stressful combinations of high salinity and low temperature in the sea. Results We sampled brown trout from two Danish populations entering different saline conditions and quantified expression of the hsp70 and Na/K-ATPases α 1b genes following acclimation to freshwater and full-strength seawater at 2°C and 10°C. An interaction effect of low t...

  13. Sexual size dimorphism in anadromous brown trout Salmo trutta.

    Science.gov (United States)

    Jonsson, B; Jonsson, N

    2015-07-01

    Anadromous trout Salmo trutta exhibits sexual size dimorphism (SSD ); females were larger than males in populations where male mean total length (LT ) at maturity was below 49 cm and females were smaller than males when mean male LT was above 49 cm, the slope of the regression of female on male LT was 0·59. In streams with mean annual discharge below 41 m(3) s(-1) , flow added significantly to a model with SSD as the dependent variable and male mean LT at maturity as the first predictor variable. There was a slight increase in SSD with increasing latitude, which may result from an increase in male size with increasing latitude. PMID:25959597

  14. Pre-migratory differentiation of wild brown trout Salmo trutta into migrant and resident individuals

    DEFF Research Database (Denmark)

    Nielsen, Christian; Aarestrup, Kim; Nørum, Ulrik;

    2003-01-01

    In February to March, wild brown trout Salmo trutta were captured by electrofishing in a natural watercourse (tributaries of the River Lille Aa, Denmark), individually tagged (Passive Integrated Transponders), and released. Representatives of the tagged brown trout were recaptured on the release...

  15. Mechanisms and consequences of hybridisation between Atlantic salmon (Salmo salar) and brown trout (Salmo trutta)

    OpenAIRE

    Diamond, Sian

    2012-01-01

    Relatively little research has been done to investigate the way postcopulatory, prezygotic mechanisms act to isolate species at the level of the gamete. This thesis uses the naturallyhybridising, externally-fertilising system of Atlantic salmon, Salmo salar, and brown trout, S. trutta, to investigate mechanisms of hybridisation through sperm-egg interactions, much of which is poorly understood. Salmon and trout experience conspecific sperm precedence during in vitro sperm co...

  16. Effects of turbidity on predation vulnerability of juvenile humpback chub to rainbow and brown trout

    Science.gov (United States)

    Ward, David L.; Morton-Starner, Rylan; Vaage, Benjamin M.

    2016-01-01

    Predation on juvenile native fish by introduced rainbow trout Oncorhynchus mykiss and brown trout Salmo trutta is considered a significant threat to the persistence of endangered humpback chub Gila cypha in the Colorado River in Grand Canyon. Diet studies of rainbow and brown trout in Glen and Grand canyons indicate that these species eat native fish, but impacts are difficult to assess because predation vulnerability is highly variable depending on the physical conditions under which the predation interactions take place. We conducted laboratory experiments to evaluate how short-term predation vulnerability of juvenile humpback chub changes in response to changes in turbidity. In overnight laboratory trials, we exposed hatchery-reared juvenile humpback chub and bonytail Gila elegans (a surrogate for humpback chub) to adult rainbow and brown trout at turbidities ranging from 0 to 1,000 formazin nephlometric units. We found that turbidity as low as 25 formazin nephlometric units significantly reduced predation vulnerability of bonytail to rainbow trout and led to a 36% mean increase in survival (24–60%, 95% CI) compared to trials conducted in clear water. Predation vulnerability of bonytail to brown trout at 25 formazin nephlometric units also decreased with increasing turbidity and resulted in a 25% increase in survival on average (17–32%, 95% CI). Understanding the effects of predation by trout on endangered humpback chub is important when evaluating management options aimed at preservation of native fishes in Grand Canyon National Park. This research suggests that relatively small changes in turbidity may be sufficient to alter predation dynamics of trout on humpback chub in the mainstem Colorado River and that turbidity manipulation may warrant further investigation as a fisheries management tool.

  17. Genetic variation in brown trout Salmo trutta across the Danube, Rhine, and Elbe headwaters: a failure of the phylogeographic paradigm?

    OpenAIRE

    Lerceteau-Köhler, Estelle; Schliewen, Ulrich; Kopun, Theodora; Weiss, Steven

    2013-01-01

    Background Brown trout Salmo trutta have been described in terms of five major mtDNA lineages, four of which correspond to major ocean basins, and one, according to some authors, to a distinct taxon, marbled trout Salmo marmoratus. The Atlantic and Danubian lineages of brown trout meet in a poorly documented contact zone in Central Europe. The natural versus human mediated origin of the Atlantic lineage in the upper Danube is a question of both theoretical and practical importance with respec...

  18. Behaviour and metabolic rates of brown trout and Atlantic salmon : Influence of food, environment and social interactions

    OpenAIRE

    Lans, Linnea

    2012-01-01

    For Atlantic salmon (Salmo salar) and brown trout (Salmo trutta), the decision to migrate or when to migrate is believed to be influenced by the individual’s metabolic rate (MR) relative its food intake. As MR was expected to be related to behaviour, the potential links between behaviour and metabolic costs was studied. For both salmon and trout the dominant individual had a higher standard metabolic rate (SMR) than its subordinate counterpart. Also, successful migrants of brown trout had a h...

  19. EFFECT OF CULTURE CONDITIONS ON REPRODUCTIVE TRAITS OF BROWN TROUT SALMO TRUTTA L.

    Directory of Open Access Journals (Sweden)

    RANDÁK T.

    2006-07-01

    Full Text Available Progeny from artificial propagation of wild brown trout (Salmo trutta L. of the Blanice river, Czech Republic, were farmed to maturity and spawned at ages three, four and five during 2002-2004. Reproductive parameters and biological quality of eggs in this farmed population were compared to those of the original wild population. ANCOVA showed no differences between wild and farmed fish in weight of eggs per female, total fecundity, or relative fecundity in any year. Significantly higher egg diameter (4.57 mm, P = 0.001 and weight (69.3 mg, P = 0.0375 were found in the wild population in 2002 and conversely in 2004, the mean egg weight was higher in the farmed population (94.7 mg, P = 0.0021. Differences in egg diameter in this year (4.64 ± 0.06 and 4.82 ± 0.06 in wild and farmed trout, respectively were close to the level of significance (P = 0.079. Mutual correlations between length or weight and studied reproductive traits were similar in both populations. Fertilization rate, duration of incubation period, egg losses during incubation and mortality of starving hatched fry were monitored in embryos and larvae of farmed population only (FxF, crosses between farmed females and wild males (FxW and wild population only (WxW. Altogether 6.3%, 5.8% and 5.4% of eggs died during incubation period in FxF, FxW and WxW, respectively. There were also no significant differences in duration of incubation period and mortality of starving fry. It can be concluded that farming conditions did not significantly affect the reproductive parameters and quality of eggs in the first generation of farmed broodstock.

  20. Density-dependent compensatory growth in brown trout (Salmo trutta in nature.

    Directory of Open Access Journals (Sweden)

    L Fredrik Sundström

    Full Text Available Density-dependence is a major ecological mechanism that is known to limit individual growth. To examine if compensatory growth (unusually rapid growth following a period of imposed slow growth in nature is density-dependent, one-year-old brown trout (Salmo trutta L. were first starved in the laboratory, and then released back into their natural stream, either at natural or at experimentally increased population density. The experimental trout were captured three times over a one-year period. We found no differences in growth, within the first month after release (May-June, between the starved fish and the control group (i.e. no evidence of compensation. During the summer however (July-September, the starved fish grew more than the control group (i.e. compensation, and the starved fish released into the stream at a higher density, grew less than those released at a natural density, both in terms of weight and length (i.e. density-dependent compensation. Over the winter (October-April, there were no effects of either starvation or density on weight and length growth. After the winter, starved fish released at either density had caught up with control fish in body size, but recapture rates (proxy for survival did not indicate any costs of compensation. Our results suggest that compensatory growth in nature can be density-dependent. Thus, this is the first study to demonstrate the presence of ecological restrictions on the compensatory growth response in free-ranging animals.

  1. Admixture analysis and stocking impact assessment in brown trout ( Salmo trutta ), estimated with incomplete baseline data

    DEFF Research Database (Denmark)

    Hansen, Michael Møller; Eg Nielsen, Einar; Bekkevold, Dorte;

    2001-01-01

    Studies of genetic interactions between wild and domesticated fish are often hampered by unavailability of samples from wild populations prior to population admixture. We assessed the utility of a new Bayesian method, which can estimate individual admixture coefficients even with data missing from...... by the mean of individual admixture coefficients. This method proved more informative than a multidimensional scaling analysis of individual-based genetic distances and assignment tests. The results showed almost complete absence of stocked, domesticated trout in samples of trout from the rivers. Consequently......, stocking had little effect on improving fisheries. In one population, the genetic contribution by domesticated trout was small, whereas in the other population, some genetic impact was suggested. Admixture in this sample of anadromous trout despite absence of stocked domesticated trout could be because...

  2. The physiological basis of the migration continuum in brown trout ( Salmo trutta)

    DEFF Research Database (Denmark)

    Boel, Mikkel; Aarestrup, Kim; Baktoft, Henrik;

    2014-01-01

    Partial migration is common in many animal taxa; however, the physiological variation underpinning migration strategies remains poorly understood. Among salmonid fishes, brown trout (Salmo trutta) is one of the species that exhibits the most complex variation in sympatric migration strategies, ex...

  3. An experimental field evaluation of winter carryover effects in semi-anadromous Brown trout (Salmo trutta)

    DEFF Research Database (Denmark)

    Midwood, Jonathan D.; Larsen, Martin Hage; Boel, Mikkel;

    2015-01-01

    For semi-anadromous brown trout, the decision whether or not to smoltify and migrate to the sea is believed to be made at the end of the preceding summer in response to both local environmental conditions and individual physiological status. Stressors experienced during the fall may therefore inf...

  4. The effects of chronological age and size on toxicity of zinc to juvenile brown trout

    Science.gov (United States)

    A series of toxicity tests were conducted to investigate the role of chronological age and organism weight on zinc tolerance in juvenile brown trout (Salmo trutta). Four different incubation temperatures were used to control the maturation of the juveniles prior to zinc exposure...

  5. Copper avoidance and mortality of juvenile brown trout (Salmo trutta) in tests with copper-sulfate-treated water from West Branch Reservoir, Putnam County, New York

    Science.gov (United States)

    Baldigo, Barry P.; Baudanza, T.P.

    2001-01-01

    Copper-avoidance tests and acute-toxicity (mortality) tests on hatchery-reared, young-of- the-year brown trout (salmo trutta) were conducted with water from West Branch Reservoir to assess the avoidance response to copper sulfate treatment, which is used occasionally by New York City Department of Environmental Protection to decrease phytoplankton populations in the reservoir. Avoidance-test results indicate that juvenile brown trout tend to avoid dissolved copper concentrations greater than about 55 ?g/L (micrograms per liter), which is the approximate avoidance-response threshold. The mean net avoidance response of brown trout to dissolved copper concentrations of 70 and 100 ?g/L, and possibly 80 ?g/L, was significantly different (at a = 0.1) from the mean net avoidance response of fish to control (untreated) water and to treated water at most other tested concentrations. Mortality-test results indicate that the 96-hr median lethal concentration (LC50) of dissolved copper was 61.5 ?g/L. All (100 percent) of the brown trout died at a dissolved copper concentration of 85 ?g/L, many died at concentrations of 62 ?g/L and 70 ?g/L, and none died in the control waters (7 ?g/L) or at concentrations of 10, 20, or 45 ?g/L. The estimated concentration of dissolved copper that caused fish mortality (threshold) was 53.5 ?g/L, virtually equivalent to the avoidance-response threshold. Additional factors that could affect the copper-avoidance and mortality response of individual brown trout and their populations in West Branch Reservoir include seasonal variations in certain water-quality parameters, copper-treatment regimes, natural fish distributions during treatment, and increased tolerance due to acclimation. These warrant additional study before the findings from this study can be used to predict the effects that copper sulfate treatments have on resident fish populations in New York City reservoirs.

  6. 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...

  7. Vitellogenin as a biomarker for estrogenic effects in brown trout, Salmo trutta: laboratory and field investigations.

    Science.gov (United States)

    Bjerregaard, Poul; Hansen, Pernille R; Larsen, Katrine J; Erratico, Claudio; Korsgaard, Bodil; Holbech, Henrik

    2008-11-01

    The sensitivity of juvenile brown trout towards estrogenic chemicals (17beta-estradiol [E2], estrone [E1], 17alpha-ethinylestradiol [EE2], 4-tert-octylphenol [OP], and n-butylparaben [BP]) was tested in laboratory experiments with plasma and liver vitellogenin concentrations as endpoints. Vitellogenin concentrations were also assessed in juvenile brown trout collected in streams affected by agricultural runoff and discharges from scattered houses in the open land. In the laboratory, juvenile brown trout were exposed to the chemicals in flow-through tanks for 7 to 12 d and concentration-response relationships for the induction of vitellogenin synthesis were obtained. The actual exposure concentrations were determined by liquid chromatography-mass spectrometry. The median plasma vitellogenin concentration in first year control brown trout reared in recirculated groundwater was 165 ng/ml with 783 ng/ml as the highest value. The median effective concentration (EC50) values for vitellogenin induction (based on plasma concentrations) were 3.7 ng EE2/L, 15 ng E2/L, 88 ng E1/L, 68 microg BP/L, and 7 microg OP/L. Median effective concentrations derived from liver vitellogenin concentrations were similar. The 166 brown trout caught in the field were mainly first and second year fish and a few third year fish. Plasma vitellogenin concentrations were below 1000 ng/L in 146 of the fish, between 1000 ng/L and 4234 ng/L in 19 fish and 5.3 x 10(6) ng/L in one male fish. Vitellogenin concentrations did not differ between first and second year fish, but were elevated in third year fish. The data may indicate that juvenile (<2 years) trout with plasma vitellogenin concentrations above 1000 ng/ml have had their vitellogenin synthesis induced by exposure to estrogens in the environment. Plasma and liver vitellogenin concentrations were closely correlated in brown trout with elevated vitellogenin concentrations. It is noteworthy, however, that exposure to synthetic estrogens (EE2, BP

  8. Genome-wide methylation study of diploid and triploid brown trout (Salmo trutta L.).

    Science.gov (United States)

    Covelo-Soto, L; Leunda, P M; Pérez-Figueroa, A; Morán, P

    2015-06-01

    The induction of triploidization in fish is a very common practice in aquaculture. Although triploidization has been applied successfully in many salmonid species, little is known about the epigenetic mechanisms implicated in the maintenance of the normal functions of the new polyploid genome. By means of methylation-sensitive amplified polymorphism (MSAP) techniques, genome-wide methylation changes associated with triploidization were assessed in DNA samples obtained from diploid and triploid siblings of brown trout (Salmo trutta). Simple comparative body measurements showed that the triploid trout used in the study were statistically bigger, however, not heavier than their diploid counterparts. The statistical analysis of the MSAP data showed no significant differences between diploid and triploid brown trout in respect to brain, gill, heart, liver, kidney or muscle samples. Nonetheless, local analysis pointed to the possibility of differences in connection with concrete loci. This is the first study that has investigated DNA methylation alterations associated with triploidization in brown trout. Our results set the basis for new studies to be undertaken and provide a new approach concerning triploidization effects of the salmonid genome while also contributing to the better understanding of the genome-wide methylation processes. PMID:25917300

  9. Occurrence and variation of egg cannibalism in brown trout Salmo trutta

    Science.gov (United States)

    Aymes, Jean-Christophe; Larrieu, Maider; Tentelier, Cédric; Labonne, Jacques

    2010-04-01

    Egg cannibalism is a common behavior among fish taxa and is largely studied in species with parental care. Heterocannibalism and filial cannibalism have both been reported in salmonids, a group with no extended parental care, but the topic remained somewhat under-documented, especially in brown trout ( Salmo trutta). In the present study, 83 spawning events were recorded finely with high-resolution video in three natural populations. Redd covering dynamics by females and the timing of cannibalism showed that eggs were vulnerable mainly during the first 120 s after spawning. Cannibalism occurred in 25% of spawnings and was principally perpetrated by peripherals but the sires also cannibalized their brood, especially after multiple mating. The probability of cannibalism increased with operational sex ratio but did not correlate with the date in spawning season. Occurrence of cannibalism also differed between populations. Our results suggest that such behavior is frequent and may reduce the fitness of parents. Its evolutionary implications for population ecology should be considered, since it appeared to be controlled by environmental and spatial factors.

  10. Differential modulation of host genes in the kidney of brown trout Salmo trutta during sporogenesis of Tetracapsuloides bryosalmonae (Myxozoa)

    OpenAIRE

    Kumar, Gokhlesh; Abd-Elfattah, Ahmed; El-Matbouli, Mansour

    2014-01-01

    Tetracapsuloides bryosalmonae (Myxozoa) is the causative agent of proliferative kidney disease in various species of salmonids in Europe and North America. In Europe, spores of T. bryosalmonae develop in the kidney of infected brown trout Salmo trutta and are released via urine to infect the freshwater bryozoan Fredericella sultana. The transcriptomes of kidneys of infected and non-infected brown trout were compared by suppressive subtractive hybridization. Differential screening and a subseq...

  11. Water-borne diclofenac affects kidney and gill integrity and selected immune parameters in brown trout (Salmo trutta f. fario)

    OpenAIRE

    Höger, Birgit; Köllner, Bernd; Dietrich, Daniel R; Hitzfeld, Bettina C

    2005-01-01

    The detection of residues of various pharmaceuticals in surface waters during the last two decades has prompted concerns about possible adverse effects of this kind of pollution on aquatic organisms. The objective of the present study was to investigate effects of the non-steroidal anti-inflammatory drug diclofenac, one of the pharmaceuticals most prevalent in surface waters, on brown trout (Salmo trutta f. fario), a salmonid species native to German rivers. Brown trout were exposed to 0.5, 5...

  12. Differential modulation of host genes in the kidney of brown trout Salmo trutta during sporogenesis of Tetracapsuloides bryosalmonae (Myxozoa).

    Science.gov (United States)

    Kumar, Gokhlesh; Abd-Elfattah, Ahmed; El-Matbouli, Mansour

    2014-10-04

    Tetracapsuloides bryosalmonae (Myxozoa) is the causative agent of proliferative kidney disease in various species of salmonids in Europe and North America. In Europe, spores of T. bryosalmonae develop in the kidney of infected brown trout Salmo trutta and are released via urine to infect the freshwater bryozoan Fredericella sultana. The transcriptomes of kidneys of infected and non-infected brown trout were compared by suppressive subtractive hybridization. Differential screening and a subsequent NCBI BLAST analysis of expressed sequence tags revealed 21 transcripts with functions that included cell stress and cell growth, ribonucleoprotein, signal transduction, ion transporter, immune response, hemoglobin and calcium metabolisms. Quantitative real time PCR was used to verify the presence of these selected transcripts in brown trout kidney at sporogonic stages of T. bryosalmonae development. Expression of cold-inducible RNA-binding protein, cyclin-dependent kinase inhibitor 2A, prothymosin alpha, transforming protein RhoA, immunoglobulin light chain and major histocompatibility complex class I were up-regulated significantly in infected brown trout. Expression of both the hemoglobin subunit beta and stanniocalcin precursor were down-regulated significantly in infected brown trout. This study suggests that cell stress and cell growth processes, signal transduction activities, erythropoiesis and calcium homeostasis of the host are modulated during sporogonic stages of parasite development, which may support the sporogenesis of T. bryosalmonae in the kidney of brown trout.

  13. The concentration of plasma metabolites varies throughout reproduction and affects offspring number in wild brown trout (Salmo trutta).

    Science.gov (United States)

    Gauthey, Zoé; Freychet, Marine; Manicki, Aurélie; Herman, Alexandre; Lepais, Olivier; Panserat, Stéphane; Elosegi, Arturo; Tentelier, Cédric; Labonne, Jacques

    2015-06-01

    In wild populations, measuring energy invested in the reproduction and disentangling investment in gametes versus investment in reproductive behavior (such as intrasexual competition or intersexual preference) remain challenging. In this study, we investigated the energy expenditure in brown trout reproductive behavior by using two proxies: variation in weight and variation of plasma metabolites involved in energy production, over the course of reproductive season in a semi natural experimental river. We estimated overall reproductive success using genetic assignment at the end of the reproductive season. Results show that triglycerides and free fatty acid concentrations vary negatively during reproduction, while amino-acids and glucose concentrations remain stable. Decrease in triglyceride and free fatty acid concentrations during reproduction is not related to initial concentration levels or to weight variation. Both metabolite concentration variations and weight variations are correlated to the number of offspring produced, which could indicate that gametic and behavioral reproductive investments substantially contribute to reproductive success in wild brown trout. This study opens a path to further investigate variations in reproductive investment in wild populations. PMID:25666363

  14. 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.

  15. The volitional travel speed varies with reproductive state in mature female brown trout Salmo trutta

    DEFF Research Database (Denmark)

    Svendsen, Jon Christian; Aarestrup, Kim; Dolby, Jes;

    2009-01-01

    This study tested the effect of reproduction on the volitional travel speed of mature female brown trout Salmo trutta L. The downstream travel speed in the pre-spawning state was 0·25 m s−1 (95% CI : 0·19, 0·34) while it increased significantly to 0·65 m s−1 (95% CI: 0·49, 0·87) in the post...

  16. Measurement of peroxisomal enzyme activities in the liver of brown trout (Salmo trutta, using spectrophotometric methods

    Directory of Open Access Journals (Sweden)

    Resende Albina D

    2003-03-01

    Full Text Available Abstract Background This study was aimed primarily at testing in the liver of brown trout (Salmo trutta spectrophotometric methods previously used to measure the activities of catalase and hydrogen peroxide producing oxidases in mammals. To evaluate the influence of temperature on the activities of those peroxisomal enzymes was the second objective. A third goal of this work was the study of enzyme distribution in crude cell fractions of brown trout liver. Results The assays revealed a linear increase in the activity of all peroxisomal enzymes as the temperature rose from 10° to 37°C. However, while the activities of hydrogen peroxide producing oxidases were strongly influenced by temperature, catalase activity was only slightly affected. A crude fraction enriched with peroxisomes was obtained by differential centrifugation of liver homogenates, and the contamination by other organelles was evaluated by the activities of marker enzymes for mitochondria (succinate dehydrogenase, lysosomes (aryl sulphatase and microsomes (NADPH cytochrome c reductase. For peroxisomal enzymes, the activities per mg of protein (specific activity in liver homogenates were strongly correlated with the activities per g of liver and with the total activities per liver. These correlations were not obtained with crude peroxisomal fractions. Conclusions The spectrophotometric protocols originally used to quantify the activity of mammalian peroxisomal enzymes can be successfully applied to the study of those enzymes in brown trout. Because the activity of all studied peroxisomal enzymes rose in a linear mode with temperature, their activities can be correctly measured between 10° and 37°C. Probably due to contamination by other organelles and losses of soluble matrix enzymes during homogenisation, enzyme activities in crude peroxisomal fractions do not correlate with the activities in liver homogenates. Thus, total homogenates will be used in future seasonal and

  17. The influence of northern pike on the diet of brown trout

    OpenAIRE

    Jansson, Julia

    2015-01-01

    The predation of the northern pike (Esox lucius) has recently been found to initiate divergence in the size structuration of whitefish (Coregonus lavaretus) in Scandinavian lakes. The whitefish community responds to the predation with two different strategies: avoiding the pike by feeding in the pelagic zone with the cost of limited growth, or feeding in the littoral zone, delaying maturation to reach a size which is less subject to predation (Öhlund 2012). Brown trout (Salmo trutta) is an op...

  18. Forest-stream linkages : Experimental studies of foraging and growth of brown trout (Salmo trutta L).

    OpenAIRE

    Gustafsson, Pär

    2008-01-01

    Riparian vegetation along streams and rivers affects the aquatic community in numerous ways and often operates as a link for energy flux between forest and streams. The studies presented in this licentiate thesis focus on light and terrestrial invertebrates, two factors influenced by riparian zone structure, which potentially affect stream ecosystems and thus also brown trout (Salmo trutta). Paper I is a laboratory experiment where I study size dependent foraging behavior on surface-drifting ...

  19. Linking landscape characteristics, streamwater acidity and brown trout (Salmo trutta) distributions in a boreal stream network

    OpenAIRE

    Buffam, Ishi

    2007-01-01

    Perturbations of stream ecosystems are often mediated by the terrestrial watershed, making the understanding of linkages between watersheds and streams essential. In this thesis I explore the connections between landscape characteristics, streamwater acidity and brown trout (Salmo trutta) distributions in Krycklan, a 67 km2 boreal stream network in northern Sweden. The study focuses on hydrochemical changes during the snowmelt-driven spring flood, a period of episodic acidity which is thought...

  20. Histological and stereological characterization of brown trout (Salmo trutta f. fario) trunk kidney.

    Science.gov (United States)

    Resende, Albina D; Lobo-da-Cunha, Alexandre; Malhão, Fernanda; Franquinho, Filipa; Monteiro, Rogério A F; Rocha, Eduardo

    2010-12-01

    The large variability in kidney morphology among fish makes it difficult to build a "universal" model on its function and structure. Therefore, a morphological study of brown trout trunk kidney was performed, considering potential seasonal and sex effects. Three-year-old specimens of both sexes were collected at four stages of their reproductive cycle. Kidney was processed for light and electron microscopy. The relative volumes of renal components, such as renal corpuscles and different nephron tubules, were estimated by stereological methods. Qualitatively, the general nephron structure of brown trout was similar to that described for other glomerular teleost species. Quantitatively, however, differences in the relative volume of some renal components were detected between sexes and among seasons. Particularly, highest values of vacuolized tubules and new growing tubules were observed after spawning, being more relevant in females. Despite seasonal changes, more linear correlations were found between those parameters and the reno-somatic index than the gonado-somatic index. Thus, we verified that some brown trout renal components undergo sex dependent seasonal variations, suggesting a morphological adaptation of the components to accomplish physiological needs. These findings constitute a baseline for launching studies to know which factors govern the morphological variations and their functional consequences.

  1. Microsatellite and mitochondrial DNA polymorphism reveals life history dependent interbreeding between hatchery and wild brown trout ( Salmo trutta L.)

    DEFF Research Database (Denmark)

    Hansen, Michael Møller; Ruzzante, D.E.; Eg Nielsen, Einar;

    2000-01-01

    The effects of stocking hatchery trout into wild populations were studied in a Danish river, using microsatellite and mitochondrial DNA (mtDNA) markers. Baseline samples were taken from hatchery trout and wild trout assumed to be unaffected by previous stocking. Also, samples were taken from...

  2. Effects of nonylphenol on key hormonal balances and histopathology of the endangered Caspian brown trout (Salmo trutta caspius).

    Science.gov (United States)

    Shirdel, Iman; Kalbassi, Mohammad Reza

    2016-01-01

    Endocrine disruptor chemicals (EDCs) potentially pose a hazard to endangered species. Evaluation of the sensitivity of these species to EDCs could be helpful for protecting their populations. So, the present study investigated the adverse effects of nonylphenol, an EDC, on the endocrine hormones and histopathology of male and female juvenile Caspian brown trout (Salmo trutta caspius) following 21 days of exposure to nominal concentrations of 1, 10 and 100 μg/l. The results showed that the HSI and plasma total calcium of male and female fishes exposed to 100 μg/l nonylphenol were significantly increased compared with the control groups (P0.05). No significant effect of nonylphenol exposure was observed on male plasma TSH levels (P>0.05), whereas, in females, nonylphenol at all concentrations significantly reduced TSH levels. A bell-shaped response was observed in male and female plasma GH levels. Moreover, various histopathological lesions were observed in gill and intestine tissues of fishes exposed to different nonylphenol concentrations. These results demonstrate the high sensitivity of this endangered species to even environmentally relevant concentrations of nonylphenol. Furthermore, Caspian brown trout could be used as bioindicators reflecting the toxicity of nonylphenol. PMID:26811907

  3. Brown trout ( Salmo trutta ) stocking impact assessment using microsatellite DNA markers

    DEFF Research Database (Denmark)

    Hansen, Michael Møller; Ruzzante, D.E.; Eg Nielsen, Einar;

    2001-01-01

    between the wild and hatchery populations. We assessed whether wild populations were introgressed by stocked hatchery trout by performing assignment tests to determine population of origin and estimating maximum potential introgression rates. The results suggested that genetic introgression by hatchery...... population, suggesting that extinction of the original population had taken place. The study demonstrates that microsatellite analysis provides a useful tool for distinguishing heavily introgressed populations from those unaffected by stocking. The information can be used to assist in (1) prioritizing...

  4. Comparison of pigment cell ultrastructure and organisation in the dermis of marble trout and brown trout, and first description of erythrophore ultrastructure in salmonids.

    Science.gov (United States)

    Djurdjevič, Ida; Kreft, Mateja Erdani; Sušnik Bajec, Simona

    2015-11-01

    Skin pigmentation in animals is an important trait with many functions. The present study focused on two closely related salmonid species, marble trout (Salmo marmoratus) and brown trout (S. trutta), which display an uncommon labyrinthine (marble-like) and spot skin pattern, respectively. To determine the role of chromatophore type in the different formation of skin pigment patterns in the two species, the distribution and ultrastructure of chromatophores was examined with light microscopy and transmission electron microscopy. The presence of three types of chromatophores in trout skin was confirmed: melanophores; xanthophores; and iridophores. In addition, using correlative microscopy, erythrophore ultrastructure in salmonids was described for the first time. Two types of erythrophores are distinguished, both located exclusively in the skin of brown trout: type 1 in black spot skin sections similar to xanthophores; and type 2 with a unique ultrastructure, located only in red spot skin sections. Morphologically, the difference between the light and dark pigmentation of trout skin depends primarily on the position and density of melanophores, in the dark region covering other chromatophores, and in the light region with the iridophores and xanthophores usually exposed. With larger amounts of melanophores, absence of xanthophores and presence of erythrophores type 1 and type L iridophores in the black spot compared with the light regions and the presence of erythrophores type 2 in the red spot, a higher level of pigment cell organisation in the skin of brown trout compared with that of marble trout was demonstrated. Even though the skin regions with chromatophores were well defined, not all the chromatophores were in direct contact, either homophilically or heterophilically, with each other. In addition to short-range interactions, an important role of the cellular environment and long-range interactions between chromatophores in promoting adult pigment pattern

  5. Proposed standard-weight (Ws) equation and length-categorization standards for brown trout (Salmo trutta) in lentic habitats

    Science.gov (United States)

    Hyatt, M.W.; Hubert, W.A.

    2001-01-01

    We developed a standard-weight (Ws) equation for brown trout (Salmo trutta) in lentic habitats by applying the regression-line-percentile technique to samples from 49 populations in North America. The proposed Ws equation is log10 Ws = -5.422 + 3.194 log10 TL, when Ws is in grams and TL is total length in millimeters. The English-unit equivalent is log10 Ws = -3.592 + 3.194 log10 TL, when Ws is in pounds and TL is total length in inches. The equation is applicable for fish of 140-750 mm TL. Proposed length-category standards to evaluate fish within populations are: stock, 200 mm (8 in); quality, 300 mm (12 in); preferred, 400 mm (16 in); memorable, 500 mm (20 in); and trophy, 600 mm (24 in).

  6. Impact of groundwater abstraction on physical habitat of brown trout (Salmo trutta) in a small Danish stream

    DEFF Research Database (Denmark)

    Olsen, M.; Bøgh, E.; Pedersen, Stig;

    2009-01-01

    discharge reference conditions. Stream physical habitat conditions (WUA) were simulated for four life stages of trout using a hydraulic habitat model (RHYHABSIM). The impact of groundwater abstraction on WUA for trout was assessed by combined simulations from the NAM-model and the RHYHABSIM-model. The model......The purpose of this study was to assess the impact of groundwater abstraction on stream discharge and physical habitat conditions for brown trout (Salmo trutta) in a small Danish stream. Stream discharge was simulated using a lumped hydrological model (NAM) and a scenario was set up for stream...... abstraction during summer. WUA for adult trout was mainly controlled by suitable water depths (>40 cm) even under conditions without abstraction. On annual basis WUA for fry and juvenile trout was most affected by abstraction. Future modelling should consider improving simulation of low discharges...

  7. Effects of Stripping Frequency on Semen Quality of Endangered Caspian Brown Trout, Salmo trutta caspius

    Directory of Open Access Journals (Sweden)

    Saeed Hajirezaee

    2009-01-01

    Full Text Available Problem statement: Because of dramatic declines in stocks of endangered Caspian brown trout males, Salmo trutta caspius in Caspian Sea, each male brooder is stripped indispensably more than once during the spawning season in other to artificial insemination in hatchery. The aim of the present study was to assay the changes of indicators of semen quality (sperm motility, sperm production, semen volume and chemical composition of seminal fluid during these sequential strippings. Approach: The 11 tagged males were stripped four times every 12-14 days with beginning of spermiation period (2 December 2008 towards its end (10 January 2008. One-way Analysis Of Variance (ANOVA was employed to analyze differences between means of semen parameters. Also, the relationships between semen parameters were tested using the bivariate correlation coefficients of Pearson. Results: The semen volume, sperm density, osmolality and the concentrations of Na+, Cl-, K+, Ca2+, Mg2+ and total protein gradually decreased whereas the values of glucose and triglyceride had no significant changes during sequential strippings. Also, the values of semen pH, the percentage (5s post-activation and duration of motility were statistically stable until third stripping but a decrease was recorded for these parameters in the fourth stripping. As well as, significant positive correlations were found for sperm density vs. K+, Cl-, Na+, Ca2+, Mg2+, total protein, spermatocrit; the percentage of motile spermatozoa Vs Ca2+, Mg2+, K+, Cl-, Na+, total protein and also the duration of motility Vs K+, Cl-, total protein and pH. Conclusion: The semen quality of Caspian brown trout males decrease in successive strippings during spawning season. Also, the knowledge on values and correlations between the sperm motility characteristics and the composition of seminal fluid could be useful to formulation of a species-specific extender solution for cryopreservation of semen of Caspian brown trout.

  8. The Diet of the Brown Trout Salmo trutta (L.) during the Reproductive Period: Size-Related and Sexual Effects

    Science.gov (United States)

    Montori, Albert; Tierno de Figueroa, J. Manuel; Santos, Xavier

    2006-10-01

    We investigated the autumnal diet of the brown trout Salmo trutta, in a Prepyrenean stream (NW Iberian Peninsula) focusing on intraspecific dietary differences related to size and sex. The diet of trout included 18 types of prey, with Plecoptera and Ephemeroptera nymphs and Diptera larvae as the most consumed taxa. Large trout ate larger prey, than did small trout, and also increased the consumption of terrestrial-surface prey with respect to aquatic-benthic prey. As terrestrial-surface preys were larger than aquatic-benthic prey, the size-related differences in the diet of trout were related to gape-limitations. Although male and female trout did not differ in size, we found that males foraged on a more diverse type of prey than females, probably owing to male territoriality during the reproductive period. This study provides new evidence of dietary plasticity in the brown trout and confirms the importance of local dietary studies to better understand factors which drive trophic ecology of predators.

  9. Adhesion to brown trout skin mucus, antagonism against cyst adhesion and pathogenicity to rainbow trout of some inhibitory bacteria against Saprolegnia parasitica .

    Science.gov (United States)

    Carbajal-González, M T; Fregeneda-Grandes, J M; González-Palacios, C; Aller-Gancedo, J M

    2013-04-29

    Biological control of saprolegniosis with bacteria might be an alternative to the use of chemical compounds. Among criteria for the selection of such bacteria are their absence of pathogenicity to fish and their ability to prevent adhesion of the pathogen to the skin mucus. The pathogenicity to rainbow trout of 21 bacterial isolates with in vitro inhibitory activity against Saprolegnia parasitica was studied. Fifteen of the isolates, identified as Aeromonas sobria, Pantoea agglomerans, Pseudomonas fluorescens, Serratia fonticola, Xanthomonas retroflexus and Yersinia kristensenii, were non-pathogenic when injected into rainbow trout. Their capacity to adhere to the skin mucus of male and female brown trout and to reduce the adhesion of S. parasitica cysts under exclusion, competition and displacement conditions was tested. The 15 bacterial isolates showed a low adhesion rate, ranging between 1.7% (for an A. sobria isolate) and 15.3% (a P. fluorescens isolate). This adhesion was greater in the case of mucus from male brown trout than from females. Similarities in the adhesion to male mucus and other substrates and correlation to that observed to polystyrene suggest that adhesion to skin mucus does not depend on the substrate. A high percentage (88.9%) of the S. parasitica cysts adhered to the skin mucus of male brown trout. Almost all of the bacteria reduced this adhesion ratio significantly under exclusion and competition conditions. However, only half of the isolates displaced cysts from skin mucus, and more bacterial cells were necessary for this effect. A novel method to study the adhesion of S. parasitica cysts to skin mucus of trout and their interactions with inhibitory bacteria is described. PMID:23670078

  10. 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

  11. Effects of immobilization by electricity and MS-222 on brown trout broodstock and their progeny

    Science.gov (United States)

    Redman, S.D.; Meinertz, J.R.; Gaikowski, M.P.

    1998-01-01

    To determine the effects of electrically and chemically induced immobilization on postspawn broodstock and their progeny, age-2 and age-3 female broodstock and age-2 male broodstock of brown trout Salmo trutta were immobilized with electricity or tricaine methanesulfonate (MS-222), stripped of their eggs or milt, and weighed. Eggs taken from electrically immobilized females were fertilized with milt taken from age-2 males that were immobilized with electricity, and eggs taken from females immobilized with MS-222 were fertilized with milt taken from age-2 males that were immobilized with MS-222. After spawning, the mortality and weight of broodstock were compared twice over a 6-month period. Egg viability and growth of offspring fry from each treatment group were also compared. Electricity induced complete and consistent immobilization in brown trout broodstock. Electrically immobilized fish were more easily handled than fish immobilized with MS-222; however, electrically immobilized fish survival (70%) was significantly less than fish immobilized with MS-222 (83%). Broodstock growth differences were only noted at 6 months postexposure, when the mean weight of electrically immobilized fish was slightly less than the weight of fish immobilized with MS-222. Broodstock immobilization by electricity did not reduce egg viability or fry growth.

  12. Increased diversity of egg-associated bacteria on brown trout (Salmo trutta) at elevated temperatures.

    Science.gov (United States)

    Wilkins, Laetitia G E; Rogivue, Aude; Schütz, Frédéric; Fumagalli, Luca; Wedekind, Claus

    2015-01-01

    The taxonomic composition of egg-associated microbial communities can play a crucial role in the development of fish embryos. In response, hosts increasingly influence the composition of their associated microbial communities during embryogenesis, as concluded from recent field studies and laboratory experiments. However, little is known about the taxonomic composition and the diversity of egg-associated microbial communities within ecosystems; e.g., river networks. We sampled late embryonic stages of naturally spawned brown trout at nine locations within two different river networks and applied 16S rRNA pyrosequencing to describe their bacterial communities. We found no evidence for a significant isolation-by-distance effect on the composition of bacterial communities, and no association between neutral genetic divergence of fish host (based on 11 microsatellites) and phylogenetic distances of the composition of their associated bacterial communities. We characterized core bacterial communities on brown trout eggs and compared them to corresponding water samples with regard to bacterial composition and its presumptive function. Bacterial diversity was positively correlated with water temperature at the spawning locations. We discuss this finding in the context of the increased water temperatures that have been recorded during the last 25 years in the study area. PMID:26611640

  13. Daytime habitat selection for juvenile parr brown trout (Salmo trutta in small lowland streams

    Directory of Open Access Journals (Sweden)

    Conallin J.

    2014-03-01

    Full Text Available Physical habitat is important in determining the carrying capacity of juvenile brown trout, and within freshwater management. Summer daytime physical habitat selection for the parr lifestage (7–20 cm juvenile brown trout (Salmo trutta was assessed in 6 small lowland streams. Habitat preference was determined for the four variables; water velocity, water depth, substrate and cover, and the preferences for physical habitat selection were expressed in terms of habitat suitability indices (HSI’s. The statistical confidence of HSI’s was evaluated using power analysis. It was found that a minimum of 22 fish observations was needed to have statistical confidence in the HSIs for water depth, and a minimum of 92 fish observations for water velocity during daytime summer conditions. Generally parr were utilising the deeper habitats, indicating preference for deeper water. Cover was also being selected for at all sites, but selection was inconsistent among sites for the variables substrate and velocity. The results indicate that during daytime summer conditions water depth is a significant variable for parr habitat selection in these small lowland streams, with cover also being important. Therefore, daytime refugia may be a critical limiting factor for parr in small lowland streams, and important for stream management actions under the Water Framework Directive.

  14. Some Reproductive Features of Brown Trout (Salmo trutta macrostigma Dumeril, 1858 and its Larval Development under Culture Conditions

    Directory of Open Access Journals (Sweden)

    O. Demir, İ. Gülle1, E. Gümüş2*, F. Küçük, A. Günlü and K. Kepenek3

    2010-10-01

    Full Text Available In this study, some reproductive features of wild brown trout (Salmo trutta macrostigma Dumeril, 1858 populations in Aksu, Eşen, Alara and Alakır streams in Turkey were examined and larval development was also investigated in two different culture conditions established on Eşen Stream (Trial 1 and at the Research Unit of Eğirdir Faculty of Fisheries at Süleyman Demirel University (Trial 2. The spawning time of brown trout in Aksu Stream in the second half of December was different from other localities, at the end of the January and in the first week of February. The gonadosomatic index values ranged between 17.5 and 19.8%, the mean egg diameters of females in all localities were between 3.51 and 3.78 mm (P<0.05. The incubation lasted for 370 and 390 day-degree (10.5-10.9 ºC, and the yolk-sac of the larvae was absorbed in 28 and 32 days in trials 1 and 2, respectively. The mean live weight (LW, total length (TL and mouth widths (MW in start-fed larvae and those with absorbed yolk-sac in both trials showed non significant differences before the 25th day of the trial. On the 25th, 50th, 75th and 100th day, the mean LW, TL and MW values of the larvae in the trial 1, however, ranged from 108.30 to 547.30 mg, 23.05 to 42.74 mm and 2441 to 3993 µm; whereas these values in trial 2 were 91.30 to 366.60 mg; 20.04 to 35.18 mm and 2123 to 3386 µm, respectively. The differences among the mean values were significant (P<0.05.

  15. Long-term trends in naturalized rainbow trout (Oncorhynchus mykiss) populations in the upper Esopus Creek, Ulster County, New York, 2009–15

    Science.gov (United States)

    George, Scott D.; Baldigo, Barry P.

    2016-05-13

    The U.S. Geological Survey, in cooperation with Cornell Cooperative Extension of Ulster County, New York State Energy Research and Development Authority, the New York State Department of Environmental Conservation, and the New York City Department of Environmental Protection, surveyed fish communities annually on the main stem and tributaries of the upper Esopus Creek, Ulster County, New York, from 2009 to 2015. This report summarizes the density, biomass, and size structure of rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta) populations from the 2015 surveys along with data from the preceding 6 years. The mean density of rainbow trout populations in 2015 was 98 fish per 0.1 hectare, which was the highest value observed since 2010, and the mean biomass of rainbow trout populations in 2015 was 864 grams per 0.1 hectare, which was the highest value observed since 2012.

  16. Sex hormone concentrations and gonad histology in brown trout (Salmo Trutta) exposed to 17β-estradiol and bisphenol A

    DEFF Research Database (Denmark)

    B Bjerregaard, Lisette; Lindholst, Christian; Korsgaard, Bodil;

    2008-01-01

    Abstract: The impact of 17 beta-estradiol (E2) and bisphenol A (BPA) on steroid hormone levels and gonad development in brown trout (Salmo trutta) was determined. Exposure took place from 0 to 63 days post-fertilisation (dpf) and gonad development was followed till 400 dpf. The onset of xenoestro...

  17. Patterns of cell proliferation and cell death in the developing retina and optic tectum of the brown trout.

    NARCIS (Netherlands)

    Candal, E.; Anadon, R.; Grip, W.J. de; Rodriguez-Moldes, I.

    2005-01-01

    We have analyzed the patterns of cell proliferation and cell death in the retina and optic tectum of the brown trout (Salmo trutta fario) throughout embryonic and postembryonic stages. Cell proliferation was detected by immunohistochemistry with an antibody against the proliferating cell nuclear ant

  18. Decline of brown trout () in Switzerland - How to assess potential causes in a multi-factorial cause-effect relationship

    OpenAIRE

    Burkhardt-Holm, Patricia

    2008-01-01

    Decline of brown trout (Salmo trutta) in Switzerland - How to assess potential causes in a multi-factorial cause-effect relationship correspondence: Corresponding author. (Burkhardt-Holm, Patricia) (Burkhardt-Holm, Patricia) Institute Man-Society-Environment, Department of Environmental Sciences, University of Basel - Vesalgasse 1--> , CH-4051 Basel--> , Tel. +41 ? 61 ? 267 04 02--> - SWITZERL...

  19. Effects of salmon lice infection and salmon lice protection on fjord migrating Atlantic salmon and brown trout post-smolts

    DEFF Research Database (Denmark)

    Sivertsgard, Rolf; Thorstad, Eva B.; Okland, Finn;

    2007-01-01

    fjord system and had, thus, entered the ocean when the more pathogenic pre-adult and adult lice stages developed. The brown trout, in comparison to Atlantic salmon, remained to a larger extent than Atlantic salmon in the inner part of the fjord system. No effect of salmon lice infection, or protection...

  20. Genetic diversity in Chilean populations of rainbow trout, Oncorhynchus mykiss

    Directory of Open Access Journals (Sweden)

    Claudia B Cárcamo

    2015-03-01

    Full Text Available The rainbow trout Oncorhynchus mykiss, was first introduced in Chile between 1905 and 1920 and is currently widely distributed in Chile from Antofagasta (23°S to Patagonia (55°S. The broad range of the geographic and climatic distributions of this species in Chile offers a unique opportunity to study the effect of naturalization of an introduced species on its genetic variability. It is of particular importance to observe the genetic variability of populations in the northern range of this species distribution, in a transition zone where a Mediterranean-type climate changes to an arid climate. The present study analyzed allozymic variability and distribution within and between populations of O. mykiss from the river basins of Elqui and Limari rivers, and six culture strains, using starch-gel protein electrophoresis. Populations were found to be in Hardy-Weinberg equilibrium and the average values of He (0.045, polymorphism (13.9% and allele per locus (1.19 are similar to rainbow trout in its native distributional range. About 77.8% of the genetic variability was within population, similar to the variability reported for wild populations in the northern hemisphere. However, a marked genetic differentiation between wild populations was also found. This is likely to be the consequence of initial founder effects followed by subsequent introgression of resident populations caused by reseeding with trout of different origins in both basins.

  1. Uptake of 17{beta}-estradiol and biomarker responses in brown trout (Salmo trutta) exposed to pulses

    Energy Technology Data Exchange (ETDEWEB)

    Knudsen, Jacob J.G.; Holbech, Henrik; Madsen, Steffen S. [Institute of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense (Denmark); Bjerregaard, Poul, E-mail: poul@biology.sdu.dk [Institute of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense (Denmark)

    2011-12-15

    In streams, chemicals such as 17{beta}-estradiol (E2) are likely to occur in pulses. We investigated uptake and biomarker responses in juvenile brown trout (Salmo trutta) of 3- or 6-h pulses of concentrations up to 370 ng E2 L{sup -1}. Uptake by the fish was estimated from disappearance of E2 from tank water. A single 6-h pulse of 370 ng E2 L{sup -1} increased the plasma vitellogenin concentration, liver Er{alpha}- and vitellogenin-mRNA. Exposure to 150-160 ng E2 L{sup -1} for 6 h increased vitellogenin in one experiment but not in another. Two 6-h pulses had a larger effect one pulse. Brown trout in the size range 24-74 g took up E2 linearly with time and exposure concentration with a concentration ratio rate of 20.2 h{sup -1}. In conclusion, the threshold for induction of estrogenic effects in juvenile brown trout at short term pulse exposure appears to be in the range 150-200 ng E2 L{sup -1}. - Highlights: > We investigated estrogenic effects of pulse exposure of 17{beta}-estradiol in brown trout. > We used induction of vitellogenin and gene expression as biomarkers. > The threshold for effects after 6 h pulses ranges between 150 and 200 ng E2 L{sup -1}. > E2 is taken up in {approx}50 g fish linearly with time and concentration at 20 h{sup -1}. - The threshold concentration for induction of estrogenic effects in brown trout upon short term (6 h) exposure is in the range 150-200 ng E2 L{sup -1}.

  2. Spawning trout Salmo trutta L. populations in the Cummeragh System, Co. Kerry

    OpenAIRE

    Fahy, E

    1982-01-01

    Concentrations totalling more than 300 spawning trout from five sites at three parts of the Cummeragh system were examined in 1980. The majority of the fish were sea trout but some brown trout and precocious males occurred at every site. Of the various physical characteristics of the sites, numbers of fish displayed the most consistent relationship with the volume of water in the pools where they occurred. Trout ranged from 22cm to 68cm fork length and maiden fish of two sea summers comprised...

  3. 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.

  4. Sediment transport and siltation of brown trout (Salmo trutta L.) spawning gravels in chalk streams

    Science.gov (United States)

    Acornley, R. M.; Sear, D. A.

    1999-02-01

    Deposition rates of fine sediment into brown trout spawning gravels were measured at monthly intervals for a period of one year in a small channel of the River Test, Hampshire. Data were also collected on stream discharge, water depth, flow velocity and suspended sediment concentrations. Deposition rates followed a seasonal pattern and were maximal during periods of high discharge in the late winter/early spring when suspended sediment concentrations were high. The material deposited in the spawning gravels included silts and fine sands (<250 m) that were transported in suspension and coarser fragments of low density tufa-like material that were transported as bed load. The ecological implications of fine sediment deposition for salmonid egg survival in chalk streams are considered.

  5. Kodiak brown bear population on Kodiak Island, Alaska

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Methods and estimates of the Brown bear population on Kodiak Island. The total number of Kodiak Brown Bears on Kodiak Island has been estimated to be 1669. Three...

  6. The influence of three methods of gravel cleaning on brown trout, Salmo trutta, egg survival

    Science.gov (United States)

    Shackle, Victoria J.; Hughes, Simon; Lewis, Vaughan T.

    1999-02-01

    Siltation of spawning gravels in upland rivers appears to be an increasing hindrance to salmonids' spawning success. River managers seek an effective and non-labour intensive means of loosening gravel and reducing fine material, so improving spawning success; this study compared three practical gravel cleaning techniques, applied at realistic (rather than intensive) levels, by assessing survival to hatching of buried brown trout, Salmo trutta L., ova at five sites on four rivers with gravel substrate in southern England. Each site consisted of six reaches, of which three were cleaned by tractor rotovating, high pressure jet washing and pump washing; these were compared with adjacent, untreated reaches. Brown trout ova were buried in both fine mesh and coarse mesh boxes in each reach.Significant improvements (at P<0·05) in survival (number of live alevins) were found in three of the five pump washed reaches, two of the five tractor rotovated reaches and one pressure washed reach when the data were analysed by site. When data from all five sites were analysed together, all treated reaches showed a significant improvement (at P<0·05) in egg survival to hatching compared with control reaches for fine mesh egg boxes; for coarse mesh boxes only pump washed reaches showed such an improvement.We feel that pump-washing provides the most effective, inexpensive and suitably non labour-intensive means of improving gravel, although ultimately it may be better to reduce the silt load of rivers. Freeze core bed samples taken before and immediately after cleaning were analysed for silt content; pump washing and high pressure washing may have reduced the amount of fine material.

  7. Induction of gynogenetic and androgenetic haploid and doubled haploid development in the brown trout (Salmo trutta Linnaeus 1758).

    Science.gov (United States)

    Michalik, O; Dobosz, S; Zalewski, T; Sapota, M; Ocalewicz, K

    2015-04-01

    Gynogenetic and androgenetic brown trout (Salmo trutta Linnaeus 1758) haploids (Hs) and doubled haploids (DHs) were produced in the present research. Haploid development was induced by radiation-induced genetic inactivation of spermatozoa (gynogenesis) or eggs (androgenesis) before insemination. To provide DHs, gynogenetic and androgenetic haploid zygotes were subjected to the high pressure shock to suppress the first mitotic cleavage. Among haploids, gynogenetic embryos were showing lower mortality when compared to the androgenetic embryos; however, most of them die before the first feeding stage. Gynogenetic doubled haploids provided in the course of the brown trout eggs activation performed by homologous and heterologous sperm (rainbow trout) were developing equally showing hatching rates of 14.76 ± 2.4% and 16.14 ± 2.90% and the survival rates at the first feeding stage of 10.48 ± 3.48% and 12.78 ± 2.18%, respectively. Significantly, lower survival rate was observed among androgenetic progenies from the diploid groups with only few specimens that survived to the first feeding stage. Cytogenetic survey showed that among embryos from the diploid variants of the research, only gynogenetic individuals possessed doubled sets of chromosomes. Thus, it is reasonable to assume that radiation employed for the genetic inactivation of the brown trout eggs misaligned mechanism responsible for the cell divisions and might have delayed or even arrested the first mitotic cleavage in the androgenetic brown trout zygotes. Moreover, protocol for the radiation-induced inactivation of the paternal and maternal genome should be adjusted as some of the cytogenetically surveyed gynogenetic and androgenetic embryos exhibited fragments of the irradiated chromosomes. PMID:25601334

  8. Genetic variation within and among Danish brown trout ( Salmo trutta L) hatchery strains, assessed by PCR-RFLP analysis of mitochondrial DNA segments

    DEFF Research Database (Denmark)

    Hansen, Michael Møller; Mensberg, Karen-Lise Dons; Rasmussen, Gorm;

    1997-01-01

    Eleven Danish brown trout hatchery strains were studied by PCR- RFLP analysis of the ND-I and ND-5/6 segments of the mitochondrial genome. For comparison, data from wild trout representing three Danish river systems also were included. Reduced variability in terms of nucleon diversity and number...

  9. Local adaptation at the transcriptome level in brown trout: evidence from early life history temperature genomic reaction norms.

    Directory of Open Access Journals (Sweden)

    Kristian Meier

    Full Text Available Local adaptation and its underlying molecular basis has long been a key focus in evolutionary biology. There has recently been increased interest in the evolutionary role of plasticity and the molecular mechanisms underlying local adaptation. Using transcriptome analysis, we assessed differences in gene expression profiles for three brown trout (Salmo trutta populations, one resident and two anadromous, experiencing different temperature regimes in the wild. The study was based on an F2 generation raised in a common garden setting. A previous study of the F1 generation revealed different reaction norms and significantly higher QST than FST among populations for two early life-history traits. In the present study we investigated if genomic reaction norm patterns were also present at the transcriptome level. Eggs from the three populations were incubated at two temperatures (5 and 8 degrees C representing conditions encountered in the local environments. Global gene expression for fry at the stage of first feeding was analysed using a 32k cDNA microarray. The results revealed differences in gene expression between populations and temperatures and population × temperature interactions, the latter indicating locally adapted reaction norms. Moreover, the reaction norms paralleled those observed previously at early life-history traits. We identified 90 cDNA clones among the genes with an interaction effect that were differently expressed between the ecologically divergent populations. These included genes involved in immune- and stress response. We observed less plasticity in the resident as compared to the anadromous populations, possibly reflecting that the degree of environmental heterogeneity encountered by individuals throughout their life cycle will select for variable level of phenotypic plasticity at the transcriptome level. Our study demonstrates the usefulness of transcriptome approaches to identify genes with different temperature reaction

  10. Tetracapsuloides bryosalmonae infection affects the expression of genes involved in cellular signal transduction and iron metabolism in the kidney of the brown trout Salmo trutta

    OpenAIRE

    Kumar, Gokhlesh; Sarker, Subhodeep; Menanteau-Ledouble, Simon; El-Matbouli, Mansour

    2015-01-01

    Tetracapsuloides bryosalmonae is an enigmatic endoparasite which causes proliferative kidney disease in various species of salmonids in Europe and North America. The life cycle of the European strain of T. bryosalmonae generally completes in an invertebrate host freshwater bryozoan and vertebrate host brown trout (Salmo trutta) Linnaeus, 1758. Little is known about the gene expression in the kidney of brown trout during the developmental stages of T. bryosalmonae. In the present study, quanti...

  11. Differential changes in growth patterns of anadromous brown trout and Atlantic salmon from the River Etneelva over a 25-year period

    OpenAIRE

    Fjørtoft, Helene Børretzen; Borgstrøm, Reidar; Skaala, Øystein

    2013-01-01

    Freshwater and marine growth of anadromous brown trout (Salmo trutta) and Atlantic salmon (Salmo salar) from the River Etneelva was analysed in relation to river, fjord and ocean temperatures during the periods 1976-1982 and 2000-2007. Anadromous brown trout grew more slowly through their first and second summers in the sea during the last observation period compared to the first period, and there were more growth checks in the scales sampled from the last period. The reduced growth in length...

  12. Influence of drought conditions on brown trout biomass and size structure in the Black Hills, South Dakota

    Science.gov (United States)

    James, Daniel A.; Wilhite, Jerry W.; Chipps, Steven R.

    2010-01-01

    We evaluated the influence of drought conditions on the biomass of brown trout Salmo trutta in Spearfish Creek, upper Rapid Creek, and lower Rapid Creek in the Black Hills of western South Dakota. Stream discharge, mean summer water temperature, the biomass of juvenile and adult brown trout, and brown trout size structure were compared between two time periods: early (2000–2002) and late drought (2005–2007). Mean summer water temperatures were similar between the early- and late-drought periods in Spearfish Creek (12.4°C versus 11.5°C), lower Rapid Creek (19.2°C versus 19.3°C), and upper Rapid Creek (9.8°C in both periods). In contrast, mean annual discharge differed significantly between the two time periods in Spearfish Creek (1.95 versus 1.50 m3/s), lower Rapid Creek (2.01 versus 0.94 m3/s), and upper Rapid Creek (1.41 versus 0.84 m3/s). The mean biomass of adult brown trout in all three stream sections was significantly higher in the early-drought than in the late-drought period (238 versus 69 kg/ha in Spearfish Creek, 272 versus 91 kg/ha in lower Rapid Creek, and 159 versus 32 kg/ha in upper Rapid Creek). The biomass of juvenile brown trout was similar (43 versus 23 kg/ha) in Spearfish Creek in the two periods, declined from 136 to 45 kg/ha in lower Rapid Creek, and increased from 14 to 73 kg/ha in upper Rapid Creek. Size structure did not differ between the early- and late-drought periods in lower Rapid and Spearfish creeks, but it did in upper Rapid Creek. In addition to drought conditions, factors such as angler harvest, fish movements, and the nuisance algal species Didymosphenia geminata are discussed as possible contributors to the observed changes in brown trout biomass and size structure in Black Hills streams.

  13. 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.

  14. Tetracapsuloides bryosalmonae infection affects the expression of genes involved in cellular signal transduction and iron metabolism in the kidney of the brown trout Salmo trutta.

    Science.gov (United States)

    Kumar, Gokhlesh; Sarker, Subhodeep; Menanteau-Ledouble, Simon; El-Matbouli, Mansour

    2015-06-01

    Tetracapsuloides bryosalmonae is an enigmatic endoparasite which causes proliferative kidney disease in various species of salmonids in Europe and North America. The life cycle of the European strain of T. bryosalmonae generally completes in an invertebrate host freshwater bryozoan and vertebrate host brown trout (Salmo trutta) Linnaeus, 1758. Little is known about the gene expression in the kidney of brown trout during the developmental stages of T. bryosalmonae. In the present study, quantitative real-time PCR was applied to quantify the target genes of interest in the kidney of brown trout at different time points of T. bryosalmonae development. PCR primers specific for target genes were designed and optimized, and their gene expression levels were quantified in the cDNA kidney samples using SYBR Green Supermix. Expression of Rab GDP dissociation inhibitor beta, integral membrane protein 2B, NADH dehydrogenase 1 beta subcomplex subunit 6, and 26S protease regulatory subunit S10B were upregulated significantly in infected brown trout, while the expression of the ferritin M middle subunit was downregulated significantly. These results suggest that host genes involved in cellular signal transduction, proteasomal activities, including membrane transporters and cellular iron storage, are differentially upregulated or downregulated in the kidney of brown trout during parasite development. The gene expression pattern of infected renal tissue may support the development of intraluminal sporogonic stages of T. bryosalmonae in the renal tubular lumen of brown trout which may facilitate the release of viable parasite spores to transmit to the invertebrate host bryozoan. PMID:25786607

  15. Modes of competition: adding and removing brown trout in the wild to understand the mechanisms of density-dependence.

    Directory of Open Access Journals (Sweden)

    Rasmus Kaspersson

    Full Text Available While the prevalence of density-dependence is well-established in population ecology, few field studies have investigated its underlying mechanisms and their relative population-level importance. Here, we address these issues, and more specifically, how differences in body-size influence population regulation. For this purpose, two experiments were performed in a small coastal stream on the Swedish west coast, using juvenile brown trout (Salmo trutta as a study species. We manipulated densities of large and small individuals, and observed effects on survival, migration, condition and individual growth rate in a target group of intermediate-sized individuals. The generality of the response was investigated by reducing population densities below and increasing above the natural levels (removing and adding large and small individuals. Reducing the density (relaxing the intensity of competition had no influence on the response variables, suggesting that stream productivity was not a limiting factor at natural population density. Addition of large individuals resulted in a negative density-dependent response, while no effect was detected when adding small individuals or when maintaining the natural population structure. We found that the density-dependent response was revealed as reduced growth rate rather than increased mortality and movement, an effect that may arise from exclusion to suboptimal habitats or increased stress levels among inferior individuals. Our findings confirm the notion of interference competition as the primary mode of competition in juvenile salmonids, and also show that the feedback-mechanisms of density-dependence are primarily acting when increasing densities above their natural levels.

  16. Survival and progression rates of anadromous brown trout kelts Salmo trutta during downstream migration in freshwater and at sea

    DEFF Research Database (Denmark)

    Aarestrup, Kim; Baktoft, Henrik; Thorstad, EB;

    2015-01-01

    The marine migration of post-spawning anadromous fish remains poorly understood. The present study examined survival and progression rates of anadromous brown trout Salmo trutta L. after spawning (kelts) during downriver, fjord, and sea migration. Kelts (n = 49) were captured in the Danish River...... Gudenaa, tagged with acoustic transmitters and subsequently recorded by automatic receivers. Kelts spent on average 25 d moving down the 45 km river and through the brackish fjord. The fish entered the Kattegat Sea between 14 April and 30 May. Eighteen of the 49 kelts disappeared in the river and fjord...... completing the reach within 4 d, suggesting that the kelts spent limited time foraging after returning to the fjord. The total survival during the entire marine migration, including the fjord, was a minimum of 29%. Our study provides data that are important for management of anadromous brown trout...

  17. Strong Effects of Temperature on the Early Life Stages of a Cold Stenothermal Fish Species, Brown Trout (Salmo trutta L.).

    Science.gov (United States)

    Réalis-Doyelle, Emilie; Pasquet, Alain; De Charleroy, Daniel; Fontaine, Pascal; Teletchea, Fabrice

    2016-01-01

    Temperature is the main abiotic factor that influences the life cycle of poikilotherms. The present study investigated the thermal tolerance and phenotypic plasticity of several parameters (development time, morphometric measures, bioenergetics) for both embryos and fry of a cold stenothermal fish species, brown trout (Salmo trutta L.) in order to allow for a holistic evaluation of the potential effects of temperature. Five temperatures (4°C, 6°C, 8°C, 10°C, and 12°C) were tested, and the effects of temperature were analyzed at three stages: hatching, emergence, and first food intake. A mean of 5,440 (S.E. ± 573) eggs, coming from seven females and seven males (seven families) captured close to Linkebeek (Belgium), were used for each temperature. Maximum survival of well-formed fry at first food intake and better use of energy budget were found at 6°C and 8°C, temperatures at which the possible contribution to the next generation should therefore be greatest. At 12°C, the experimental population fell dramatically (0.9% survival rate for well-formed fry at first food intake), and fry had almost no yolk sac at first food intake. The present results on survival at 12°C are in accordance with predictions of a sharp decrease in brown trout numbers in France over the coming decades according to climate change projections (1°C to 5°C temperature rise by 2100 for France). At 10°C, there was also a lower survival rate (55.4% at first food intake). At 4°C, the survival rate was high (76.4% at first food intake), but the deformity rate was much higher (22% at first food intake) than at 6°C, 8°C, and 10°C. The energetic budget showed that at the two extreme temperatures (4°C and 12°C) there was less energy left in the yolk sac at first food intake, suggesting a limited ability to survive starvation. PMID:27170996

  18. Strong Effects of Temperature on the Early Life Stages of a Cold Stenothermal Fish Species, Brown Trout (Salmo trutta L..

    Directory of Open Access Journals (Sweden)

    Emilie Réalis-Doyelle

    Full Text Available Temperature is the main abiotic factor that influences the life cycle of poikilotherms. The present study investigated the thermal tolerance and phenotypic plasticity of several parameters (development time, morphometric measures, bioenergetics for both embryos and fry of a cold stenothermal fish species, brown trout (Salmo trutta L. in order to allow for a holistic evaluation of the potential effects of temperature. Five temperatures (4°C, 6°C, 8°C, 10°C, and 12°C were tested, and the effects of temperature were analyzed at three stages: hatching, emergence, and first food intake. A mean of 5,440 (S.E. ± 573 eggs, coming from seven females and seven males (seven families captured close to Linkebeek (Belgium, were used for each temperature. Maximum survival of well-formed fry at first food intake and better use of energy budget were found at 6°C and 8°C, temperatures at which the possible contribution to the next generation should therefore be greatest. At 12°C, the experimental population fell dramatically (0.9% survival rate for well-formed fry at first food intake, and fry had almost no yolk sac at first food intake. The present results on survival at 12°C are in accordance with predictions of a sharp decrease in brown trout numbers in France over the coming decades according to climate change projections (1°C to 5°C temperature rise by 2100 for France. At 10°C, there was also a lower survival rate (55.4% at first food intake. At 4°C, the survival rate was high (76.4% at first food intake, but the deformity rate was much higher (22% at first food intake than at 6°C, 8°C, and 10°C. The energetic budget showed that at the two extreme temperatures (4°C and 12°C there was less energy left in the yolk sac at first food intake, suggesting a limited ability to survive starvation.

  19. Sex hormone concentrations and gonad histology in brown trout (Salmo trutta) exposed to 17beta-estradiol and bisphenol A.

    Science.gov (United States)

    Bjerregaard, Lisette Bachmann; Lindholst, Christian; Korsgaard, Bodil; Bjerregaard, Poul

    2008-05-01

    The impact of 17beta-estradiol (E2) and bisphenol A (BPA) on steroid hormone levels and gonad development in brown trout (Salmo trutta) was determined. Exposure took place from 0 to 63 days post-fertilisation (dpf) and gonad development was followed till 400 dpf. The onset of xenoestrogen metabolism was examined by measurements of whole body concentrations of bisphenol A (BPA) and its conjugation product bisphenol A glucuronic acid (BPAGA). Exposure to 500 ng E2/l led to an increase in E2 levels in the embryos and fry while 10 ng E2/l did not. Metabolic conversion of BPA to BPAGA began during the first weeks of embryonic development. Few consistent effects were found on the sex differentiation of the brown trout. Only one intersex fish (4.5%) was found among male fish at 400 dpf exposed to 500 ng E2/l. Females with male germ cells among the normally developing oocytes were observed in all groups (in up to 50% of the female fish, independently of exposure regime). The fact that exposure to 500 ng E2/l only caused subtle effects in a small number of individuals indicates that exposure during early life stages results in little to no induction of endocrine disruption in brown trout.

  20. Gonad histology and vitellogenin concentrations in brown trout (Salmo trutta) from Danish streams impacted by sewage effluent.

    Science.gov (United States)

    Bjerregaard, Lisette B; Madsen, Allan H; Korsgaard, Bodil; Bjerregaard, Poul

    2006-04-01

    Brown trout (Salmo trutta) collected from a number of Danish streams impacted by sewage effluent were examined for alterations to gonadal development and induction of vitellogenin synthesis. Among fish collected in June/July 2000/2001 and November 2002 higher levels of plasma vitellogenin were found in males from six streams impacted by sewage effluent compared to males from their respective reference sites. A direct non-competitive ELISA was developed for brown trout vitellogenin in order to perform the vitellogenin measurements. Intersex in females with no apparent relation to sewage effluent exposure was observed at all sites. In one stream, male brown trout with a very high level of vitellogenin were concomitantly found to have a high degree of vacuolation of the testes and a presence of only the early spermatogenic stage, spermatogonia. The cause of these alterations to the testis structure is unclear. However, as a high level of plasma vitellogenin in these males indicated estrogenic exposure, the vacuolation might also be a result of endocrine disruption causing delayed or disrupted spermatogenesis.

  1. Enhanced individual selection for selecting fast growing fish: the "PROSPER" method, with application on brown trout (Salmo trutta fario

    Directory of Open Access Journals (Sweden)

    Vandeputte Marc

    2004-11-01

    Full Text Available Abstract Growth rate is the main breeding goal of fish breeders, but individual selection has often shown poor responses in fish species. The PROSPER method was developed to overcome possible factors that may contribute to this low success, using (1 a variable base population and high number of breeders (Ne > 100, (2 selection within groups with low non-genetic effects and (3 repeated growth challenges. Using calculations, we show that individual selection within groups, with appropriate management of maternal effects, can be superior to mass selection as soon as the maternal effect ratio exceeds 0.15, when heritability is 0.25. Practically, brown trout were selected on length at the age of one year with the PROSPER method. The genetic gain was evaluated against an unselected control line. After four generations, the mean response per generation in length at one year was 6.2% of the control mean, while the mean correlated response in weight was 21.5% of the control mean per generation. At the 4th generation, selected fish also appeared to be leaner than control fish when compared at the same size, and the response on weight was maximal (≈130% of the control mean between 386 and 470 days post fertilisation. This high response is promising, however, the key points of the method have to be investigated in more detail.

  2. A general model of distant hybridization reveals the conditions for extinction in Atlantic salmon and brown trout.

    Directory of Open Access Journals (Sweden)

    Claudio S Quilodrán

    Full Text Available Interspecific hybridization is common in nature but can be increased in frequency or even originated by human actions, such as species introduction or habitat modification, which may threaten species persistence. When hybridization occurs between distantly related species, referred to as "distant hybridization," the resulting hybrids are generally infertile or fertile but do not undergo chromosomal recombination during gametogenesis. Here, we present a model describing this frequent but poorly studied interspecific hybridization to assess its consequences on parental species and to anticipate the conditions under which they can reach extinction. Our general model fully incorporates three important processes: density-dependent competition, dominance/recessivity inheritance of traits and assortative mating. We demonstrate its use and flexibility by assessing population extinction risk between Atlantic salmon and brown trout in Norway, whose interbreeding has recently increased due to farmed fish releases into the wild. We identified the set of conditions under which hybridization may threaten salmonid species. Thanks to the flexibility of our model, we evaluated the effect of an additional risk factor, a parasitic disease, and showed that the cumulative effects dramatically increase the extinction risk. The consequences of distant hybridization are not genetically, but demographically mediated. Our general model is useful to better comprehend the evolution of such hybrid systems and we demonstrated its importance in the field of conservation biology to set up management recommendations when this increasingly frequent type of hybridization is in action.

  3. A general model of distant hybridization reveals the conditions for extinction in Atlantic salmon and brown trout.

    Science.gov (United States)

    Quilodrán, Claudio S; Currat, Mathias; Montoya-Burgos, Juan I

    2014-01-01

    Interspecific hybridization is common in nature but can be increased in frequency or even originated by human actions, such as species introduction or habitat modification, which may threaten species persistence. When hybridization occurs between distantly related species, referred to as "distant hybridization," the resulting hybrids are generally infertile or fertile but do not undergo chromosomal recombination during gametogenesis. Here, we present a model describing this frequent but poorly studied interspecific hybridization to assess its consequences on parental species and to anticipate the conditions under which they can reach extinction. Our general model fully incorporates three important processes: density-dependent competition, dominance/recessivity inheritance of traits and assortative mating. We demonstrate its use and flexibility by assessing population extinction risk between Atlantic salmon and brown trout in Norway, whose interbreeding has recently increased due to farmed fish releases into the wild. We identified the set of conditions under which hybridization may threaten salmonid species. Thanks to the flexibility of our model, we evaluated the effect of an additional risk factor, a parasitic disease, and showed that the cumulative effects dramatically increase the extinction risk. The consequences of distant hybridization are not genetically, but demographically mediated. Our general model is useful to better comprehend the evolution of such hybrid systems and we demonstrated its importance in the field of conservation biology to set up management recommendations when this increasingly frequent type of hybridization is in action.

  4. Kinematics and energetics of swimming performance during acute warming in brown trout Salmo trutta.

    Science.gov (United States)

    Lea, J M D; Keen, A N; Nudds, R L; Shiels, H A

    2016-01-01

    This study examined how acute warming of water temperature affects the mechanical efficiency of swimming and aerobic capabilities of the brown trout Salmo trutta. Swimming efficiency was assessed using the relationship between swimming kinematics and forward speed (U), which is thought to converge upon an optimum range of a dimensionless parameter, the Strouhal number (St ). Swim-tunnel intermittent stopped-flow respirometry was used to record kinematics and measure oxygen consumption (ṀO2) of S. trutta during warming and swimming challenges. Salmo trutta maintained St between 0·2 and 0·3 at any given U over a range of temperatures, irrespective of body size. The maintenance of St within the range for maximum efficiency for oscillatory propulsion was achieved through an increase in tail-beat frequency (ftail) and a decrease in tail-beat amplitude (A) as temperature increased. Maintenance of efficient steady-state swimming was fuelled by aerobic metabolism, which increased as temperature increased up to 18° C but declined above this temperature, decreasing the apparent metabolic scope. As St was maintained over the full range of temperatures whilst metabolic scope was not, the results may suggest energetic trade-offs at any given U at temperatures above thermal optima. PMID:26563644

  5. Kinematics and energetics of swimming performance during acute warming in brown trout Salmo trutta.

    Science.gov (United States)

    Lea, J M D; Keen, A N; Nudds, R L; Shiels, H A

    2016-01-01

    This study examined how acute warming of water temperature affects the mechanical efficiency of swimming and aerobic capabilities of the brown trout Salmo trutta. Swimming efficiency was assessed using the relationship between swimming kinematics and forward speed (U), which is thought to converge upon an optimum range of a dimensionless parameter, the Strouhal number (St ). Swim-tunnel intermittent stopped-flow respirometry was used to record kinematics and measure oxygen consumption (ṀO2) of S. trutta during warming and swimming challenges. Salmo trutta maintained St between 0·2 and 0·3 at any given U over a range of temperatures, irrespective of body size. The maintenance of St within the range for maximum efficiency for oscillatory propulsion was achieved through an increase in tail-beat frequency (ftail) and a decrease in tail-beat amplitude (A) as temperature increased. Maintenance of efficient steady-state swimming was fuelled by aerobic metabolism, which increased as temperature increased up to 18° C but declined above this temperature, decreasing the apparent metabolic scope. As St was maintained over the full range of temperatures whilst metabolic scope was not, the results may suggest energetic trade-offs at any given U at temperatures above thermal optima.

  6. The effects of riparian forestry on invertebrate drift and brown trout in upland streams of contrasting acidity

    Science.gov (United States)

    Ormerod, S. J.; Jones, M. E.; Jones, M. C.; Phillips, D. R.

    Variations in macroinvertebrate drift and benthic invertebrate abundance were assessed in 30 upland Welsh streams of varying acidity (pH 6.0) and riparian land-use (conifer, moorland or native broadleaf). The consequences for the diet and condition of wild brown trout Salmo trutta were also assessed. As expected from previous studies, there were significant reductions in benthic invertebrate abundance, aquatic drift density (by >60%), aquatic drift biomass (by >35%), total drift density (by >35%) and total drift biomass (by >20%) at acid sites by comparison with circumneutral sites due largely to the scarcity of mayflies. Absolute drift from terrestrial sources was unrelated to stream pH but formed a significantly greater proportion of total drift at acid sites (30-65% of density) than at circumneutral sites (20-40%) as aquatic contributions declined. Most of this apparent land use effect reflected significantly increased terrestrial drift under broadleaves. There was no significant reduction in terrestrial or aquatic drift at conifer forest sites per se after accounting for low pH. Trout diet varied substantially between locations partly reflecting variations in drift: significantly fewer mayflies and stoneflies were eaten at acid sites, and significantly more terrestrial prey were eaten under broadleaves. However, acidity did not reduce trout condition or gut-fullness. Unexpectedly, trout condition was significantly enhanced at conifer sites, irrespective of their pH. Hence, acidity has greater effects on the benthic abundance and drift density of invertebrates in upland streams than does riparian land use. However, trout forage flexibly enough to offset any possible food deficit, for example by switching to chironomids and terrestrial invertebrates. Enhanced terrestrial contributions to invertebrate drift from riparian broadleaf trees may be important in supplementing foraging opportunities for trout where aquatic prey are scarce. These data illustrate the value

  7. The effects of riparian forestry on invertebrate drift and brown trout in upland streams of contrasting acidity

    Directory of Open Access Journals (Sweden)

    S. J. Ormerod

    2004-01-01

    disproportionately important for otherwise impoverished acid streams Keywords: brown trout, land-use, acidification, drift, forestry, streams

  8. Peroxisome proliferator-activated receptor gamma (PPARγ) in brown trout: Interference of estrogenic and androgenic inputs in primary hepatocytes.

    Science.gov (United States)

    Lopes, Célia; Madureira, Tânia Vieira; Ferreira, Nádia; Pinheiro, Ivone; Castro, L Filipe C; Rocha, Eduardo

    2016-09-01

    Peroxisome proliferator-activated receptor gamma (PPARγ) is a pivotal regulator of lipid and glucose metabolism in vertebrates. Here, we isolated and characterized for the first time the PPARγ gene from brown trout (Salmo trutta f. fario). Hormones have been reported to interfere with the regulatory function of PPARγ in various organisms, albeit with little focus on fish. Thus, primary hepatocytes isolated from juveniles of brown trout were exposed to 1, 10 and 50μM of ethinylestradiol (EE2) or testosterone (T). A significant (3 fold) decrease was obtained in response to 50μM of EE2 and to 10 and 50μM of T (13 and 14 folds), while a 3 fold increase was observed at 1μM of EE2. Therefore, trout PPARγ seems a target for natural/synthetic compounds with estrogenic or androgenic properties and so, we advocate considering PPARγ as another alert sensor gene when assessing the effects of sex-steroid endocrine disruptors. PMID:27541269

  9. First Proliferative Kidney Disease outbreak in Austria, linking to the aetiology of Black Trout Syndrome threatening autochthonous trout populations.

    Science.gov (United States)

    Gorgoglione, Bartolomeo; Kotob, Mohamed H; Unfer, Günter; El-Matbouli, Mansour

    2016-05-01

    Proliferative Kidney Disease (PKD) was diagnosed in juvenile autochthonous brown trout Salmo trutta for the first time in Austria during summer 2014. Cytology showed Tetracapsuloides bryosalmonae sporoblasts, and histology revealed sporogonic (coelozoic) and extrasporogonic (histozoic) stages. Analysis of malacosporean ribosomal small subunit revealed that this strain is closely related to European isolates, although its source is unknown. Infection and high pathogenicity were reproduced upon a pre-restocking test with specific pathogen free (SPF) juvenile trout, resulting in 100% mortality between 28 and 46 d post exposure (dpe), with high ectoparasitosis. Fish showed grade 2 of the Kidney Swelling Index and grade 3 of the PKD histological assessment. T. bryosalmonae enzootic waters were demonstrated in further locations along the River Kamp, with infected bryozoans retrieved up to 6 km upstream of the farm with the PKD outbreak. Fredericella sultana colonies collected from these locations were cultivated in laboratory conditions. Released malacospores successfully induced PKD, and contextually Black Trout Syndrome (BTS), in SPF brown trout. In the absence of co-infections mortality occurred between 59 and 98 dpe, with kidneys enlarged up to 6.74% of total body weight (normal 1.23%). This study confirms the first isolation of a pathogenic myxozoan from an Austrian river tributary of the Danube, where its 2-host life cycle is fully occurring. Its immunosuppressant action could link PKD as a key factor in the multifactorial aetiology of BTS. This T. bryosalmonae isolation provides an impetus to undertake further multi-disciplinary research, aiming to assess the impact of PKD and BTS spreading to central European regions. PMID:27137070

  10. First Proliferative Kidney Disease outbreak in Austria, linking to the aetiology of Black Trout Syndrome threatening autochthonous trout populations.

    Science.gov (United States)

    Gorgoglione, Bartolomeo; Kotob, Mohamed H; Unfer, Günter; El-Matbouli, Mansour

    2016-05-01

    Proliferative Kidney Disease (PKD) was diagnosed in juvenile autochthonous brown trout Salmo trutta for the first time in Austria during summer 2014. Cytology showed Tetracapsuloides bryosalmonae sporoblasts, and histology revealed sporogonic (coelozoic) and extrasporogonic (histozoic) stages. Analysis of malacosporean ribosomal small subunit revealed that this strain is closely related to European isolates, although its source is unknown. Infection and high pathogenicity were reproduced upon a pre-restocking test with specific pathogen free (SPF) juvenile trout, resulting in 100% mortality between 28 and 46 d post exposure (dpe), with high ectoparasitosis. Fish showed grade 2 of the Kidney Swelling Index and grade 3 of the PKD histological assessment. T. bryosalmonae enzootic waters were demonstrated in further locations along the River Kamp, with infected bryozoans retrieved up to 6 km upstream of the farm with the PKD outbreak. Fredericella sultana colonies collected from these locations were cultivated in laboratory conditions. Released malacospores successfully induced PKD, and contextually Black Trout Syndrome (BTS), in SPF brown trout. In the absence of co-infections mortality occurred between 59 and 98 dpe, with kidneys enlarged up to 6.74% of total body weight (normal 1.23%). This study confirms the first isolation of a pathogenic myxozoan from an Austrian river tributary of the Danube, where its 2-host life cycle is fully occurring. Its immunosuppressant action could link PKD as a key factor in the multifactorial aetiology of BTS. This T. bryosalmonae isolation provides an impetus to undertake further multi-disciplinary research, aiming to assess the impact of PKD and BTS spreading to central European regions.

  11. Mobility and residence of Zn in brown trout Salmo trutta: results of environmentally induced change through transfer

    Energy Technology Data Exchange (ETDEWEB)

    O' Grady, K.T.; Abdullah, M.I.

    1985-01-01

    Transfer of brown trout between environments with different Zn concentrations showed that tissue levels of Zn changed in relation to Zn concentration in the environment, but only when the trout were feeding. Uptake and release of Zn by muscle, kidney, liver, bone, and scales were investigated. Equilibrium concentrations and rate of change were tissue-dependent as well as environmentally determined. Simple mathematical models for uptake were discussed. Soft tissues had reversible Zn concentrations and change occurred with both increased and decreased environmental Zn. In contrast, skeletal tissue had irreversible Zn concentrations and an acquired high Zn concentration was not reduced with lowering of environmental Zn. In soft tissues Zn was regulated by metal pathways whereas it was unregulated in skeletal tissue, which acts as a depository for biologically useful elements. Scales were the most sensitive environmental indicator when environmental Zn levels increased but liver responded to both increase and decrease, and overall was a more reliable indicator of the whole organism.

  12. Late summer and fall use of stream margins by young-of year brown trout in a high-elevation stream

    Science.gov (United States)

    La Voie, W. J., IV; Hubert, W.A.

    1997-01-01

    We determined the relative abundance of young-of-year (YOY) brown trout (Salmo trutta) from late summer to fall during day and night in stream margin habitats of Douglas Creek, Wyoming. No significant differences in relative abundance were observed from August 14 through October 26. Few YOY brown trout were observed during the day over the entire sampling period, but significantly greater numbers were seen at night. Within stream margins, YOY brown trout of 36-75 mm total length primarily resided in concealment cover among interstices of cobbie during the day and emerged at night. Because no significant change in relative abundance was observed throughout the study period, we conclude that a shift to winter habitat did not occur up until three days prior to ice formation when the diurnal range in water temperature was 2.5-7.5??C.

  13. Use of sibling relationship reconstruction to complement traditional monitoring in fisheries management and conservation of brown trout.

    Science.gov (United States)

    Ozerov, Mikhail; Jürgenstein, Tauno; Aykanat, Tutku; Vasemägi, Anti

    2015-08-01

    Declining trends in the abundance of many fish urgently call for more efficient and informative monitoring methods that would provide necessary demographic data for the evaluation of existing conservation, restoration, and management actions. We investigated how genetic sibship reconstruction from young-of-the-year brown trout (Salmo trutta L.) juveniles provides valuable, complementary demographic information that allowed us to disentangle the effects of habitat quality and number of breeders on juvenile density. We studied restored (n = 15) and control (n = 15) spawning and nursery habitats in 16 brown trout rivers and streams over 2 consecutive years to evaluate the effectiveness of habitat restoration activities. Similar juvenile densities both in restored and control spawning and nursery grounds were observed. Similarly, no differences in the effective number of breeders, Nb(SA) , were detected between habitats, indicating that brown trout readily used recently restored spawning grounds. Only a weak relationship between the Nb(SA) and juvenile density was observed, suggesting that multiple factors affect juvenile abundance. In some areas, very low estimates of Nb(SA) were found at sites with high juvenile density, indicating that a small number of breeders can produce a high number of progeny in favorable conditions. In other sites, high Nb(SA) estimates were associated with low juvenile density, suggesting low habitat quality or lack of suitable spawning substrate in relation to available breeders. Based on these results, we recommend the incorporation of genetic sibship reconstruction to ongoing and future fish evaluation and monitoring programs to gain novel insights into local demographic and evolutionary processes relevant for fisheries management, habitat restoration, and conservation.

  14. Use of sibling relationship reconstruction to complement traditional monitoring in fisheries management and conservation of brown trout.

    Science.gov (United States)

    Ozerov, Mikhail; Jürgenstein, Tauno; Aykanat, Tutku; Vasemägi, Anti

    2015-08-01

    Declining trends in the abundance of many fish urgently call for more efficient and informative monitoring methods that would provide necessary demographic data for the evaluation of existing conservation, restoration, and management actions. We investigated how genetic sibship reconstruction from young-of-the-year brown trout (Salmo trutta L.) juveniles provides valuable, complementary demographic information that allowed us to disentangle the effects of habitat quality and number of breeders on juvenile density. We studied restored (n = 15) and control (n = 15) spawning and nursery habitats in 16 brown trout rivers and streams over 2 consecutive years to evaluate the effectiveness of habitat restoration activities. Similar juvenile densities both in restored and control spawning and nursery grounds were observed. Similarly, no differences in the effective number of breeders, Nb(SA) , were detected between habitats, indicating that brown trout readily used recently restored spawning grounds. Only a weak relationship between the Nb(SA) and juvenile density was observed, suggesting that multiple factors affect juvenile abundance. In some areas, very low estimates of Nb(SA) were found at sites with high juvenile density, indicating that a small number of breeders can produce a high number of progeny in favorable conditions. In other sites, high Nb(SA) estimates were associated with low juvenile density, suggesting low habitat quality or lack of suitable spawning substrate in relation to available breeders. Based on these results, we recommend the incorporation of genetic sibship reconstruction to ongoing and future fish evaluation and monitoring programs to gain novel insights into local demographic and evolutionary processes relevant for fisheries management, habitat restoration, and conservation. PMID:25773302

  15. Evidence for an autumn downstream migration of Atlantic salmon Salmo salar (Linnaeus) and brown trout Salmo trutta (Linnaeus) parr to the Baltic Sea

    Science.gov (United States)

    Taal, Imre; Kesler, Martin; Saks, Lauri; Rohtla, Mehis; Verliin, Aare; Svirgsden, Roland; Jürgens, Kristiina; Vetemaa, Markus; Saat, Toomas

    2014-06-01

    In the eastern Baltic rivers, anadromous salmonid parr are known to smoltify and migrate to the sea from March until June, depending on latitude, climate and hydrological conditions. In this study, we present the first records of autumn descent of brown trout Salmo trutta and Atlantic salmon Salmo salar from the Baltic Sea Basin. Otolith microchemistry analyses revealed that these individuals hatched in freshwater and had migrated to the brackish water shortly prior to capture. The fish were collected in 2006, 2008, 2009 and 2013 from Eru Bay (surface salinity 4.5-6.5 ‰), Gulf of Finland. This relatively wide temporal range of observations indicates that the autumn descent of anadromous salmonids is not a random event. These results imply that autumn descent needs more consideration in the context of the effective stock management, assessment and restoration of Baltic salmonid populations and their habitats.

  16. Identification of conserved hepatic transcriptomic responses to 17β-estradiol using high-throughput sequencing in brown trout.

    Science.gov (United States)

    Uren Webster, Tamsyn M; Shears, Janice A; Moore, Karen; Santos, Eduarda M

    2015-09-01

    Estrogenic chemicals are major contaminants of surface waters and can threaten the sustainability of natural fish populations. Characterization of the global molecular mechanisms of toxicity of environmental contaminants has been conducted primarily in model species rather than species with limited existing transcriptomic or genomic sequence information. We aimed to investigate the global mechanisms of toxicity of an endocrine disrupting chemical of environmental concern [17β-estradiol (E2)] using high-throughput RNA sequencing (RNA-Seq) in an environmentally relevant species, brown trout (Salmo trutta). We exposed mature males to measured concentrations of 1.94, 18.06, and 34.38 ng E2/l for 4 days and sequenced three individual liver samples per treatment using an Illumina HiSeq 2500 platform. Exposure to 34.4 ng E2/L resulted in 2,113 differentially regulated transcripts (FDR < 0.05). Functional analysis revealed upregulation of processes associated with vitellogenesis, including lipid metabolism, cellular proliferation, and ribosome biogenesis, together with a downregulation of carbohydrate metabolism. Using real-time quantitative PCR, we validated the expression of eight target genes and identified significant differences in the regulation of several known estrogen-responsive transcripts in fish exposed to the lower treatment concentrations (including esr1 and zp2.5). We successfully used RNA-Seq to identify highly conserved responses to estrogen and also identified some estrogen-responsive transcripts that have been less well characterized, including nots and tgm2l. These results demonstrate the potential application of RNA-Seq as a valuable tool for assessing mechanistic effects of pollutants in ecologically relevant species for which little genomic information is available. PMID:26082144

  17. Strong Effects of Temperature on the Early Life Stages of a Cold Stenothermal Fish Species, Brown Trout (Salmo trutta L.).

    OpenAIRE

    Emilie Réalis-Doyelle; Alain Pasquet; Daniel De Charleroy; Pascal Fontaine; Fabrice Teletchea

    2016-01-01

    Temperature is the main abiotic factor that influences the life cycle of poikilotherms. The present study investigated the thermal tolerance and phenotypic plasticity of several parameters (development time, morphometric measures, bioenergetics) for both embryos and fry of a cold stenothermal fish species, brown trout (Salmo trutta L.) in order to allow for a holistic evaluation of the potential effects of temperature. Five temperatures (4°C, 6°C, 8°C, 10°C, and 12°C) were tested, and the eff...

  18. Mini-P-gp and P-gp Co-Expression in Brown Trout Erythrocytes: A Prospective Blood Biomarker of Aquatic Pollution

    OpenAIRE

    Emeline Valton; Christian Amblard; François Desmolles; Bruno Combourieu; Frédérique Penault-Llorca; Mahchid Bamdad

    2015-01-01

    In aquatic organisms, such as fish, blood is continually exposed to aquatic contaminants. Multidrug Resistance (MDR) proteins are ubiquitous detoxification membrane pumps, which recognize various xenobiotics. Moreover, their expression is induced by a large class of drugs and pollutants. We have highlighted the co-expression of a mini P-gp of 75 kDa and a P-gp of 140 kDa in the primary culture of brown trout erythrocytes and in the erythrocytes of wild brown trout collected from three rivers ...

  19. 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

  20. Morphological differences in the skin of marble trout Salmo marmoratus and of brown trout Salmo trutta

    Directory of Open Access Journals (Sweden)

    Urška Sivka

    2012-07-01

    Full Text Available Despite being genetically very closely related, the marble trout Salmo marmoratus and the brown trout Salmo trutta exhibit marked phenotypic differences, particularly with regard to skin pigmentation. Histological analysis of skin from the head and gill cover of differently aged individuals of the two species was carried out in order to characterize differences in skin structure. The basic structure of skin of the individuals studied corresponded with that described for other salmonids, though the head epidermis was somewhat thicker in S. marmoratus than in S. trutta, thickening with age in both species. Numerous secretory goblet cells and sporadic secretory sacciform cells were observed in the upper and middle part of the epidermis in both species. Melanophores were present in both species only in the dermis, and were bigger in S. marmoratus and present at lower average density than in S. trutta, and more or less constant across all age classes. In adult S. marmoratus with fully established marble pigmentation, light areas at low density with small (i.e. aggregated melanophores were present, while in S. trutta melanophores were more uniformly distributed.

  1. Motility and fertilizing ability of cryopreserved Caspian brown trout (Salmo trutta caspius) sperm: Effect of post-thaw storage time and different sperm-to-egg ratios.

    Science.gov (United States)

    Golshahi, Karim; Shabani, Nariman; Aramli, Mohammad Sadegh; Noori, Elnaz

    2015-10-01

    This study was designed to test the effect of post-thaw storage time on sperm motility parameters of Caspian brown trout (n=7). Furthermore, we investigated the effect of sperm-to-egg ratios of 100,000:1, 300,000:1 and 600,000:1 on fertility of cryopreserved Caspian brown semen. Quality was assessed by measuring sperm motility parameters and fertilization rates at the eyed and hatching stages. The percentage of post-thawed sperm motility, curvilinear velocity (VCL) and amplitude of lateral head displacement (ALH) were not affected by 60 min of storage, whereas a decrease in straight line velocity (VSL), average path velocity (VAP) and linearity (LIN) were found in cryopreserved semen. Thus, the cryopreserved sperm of Caspian brown trout could be stored up to 60 min without loss of the percentage of sperm motility. The fertilization rate was not affected by 60 min of post-thaw storage and was over 70% for sperm-to-egg ratios of both 300,000 and 600,000:1. To our knowledge, this study is the first to report the high post-thaw fertilization ability of Caspian brown trout semen at a sperm-to-egg ratio as low as 300,000:1. This procedure after scaling up can be recommended for routine Caspian brown trout sperm cryopreservation. PMID:26255243

  2. Expansion of Non-Native Brown Trout in South Europe May Be Inadvertently Driven by Stocking: Molecular and Social Survey in the North Iberian Narcea River

    Directory of Open Access Journals (Sweden)

    Jose L. Horreo

    2015-07-01

    Full Text Available The biological and anthropogenic (management factors that may contribute to the expansion of non-native lineages in managed fish have been studied in this work taking brown trout (Salmo trutta as a model species. The changes of users’ opinion about stocking was studied employing social science methodology (surveys. The evolution of hatchery stocks together with the outcome of stocking were analysed with two genetic tools: the LDH-C1* locus (marker of non-native stocks and six microsatellite loci (for assignment of wild trout to the natural population or putative hatchery stocks. Consulted stakeholders were convinced of the correctness of releasing only native stocks, although in practice the hatcheries managed by them contained important proportions of non-native gene carriers. Our results suggest that allochthonous individuals perform better and grow faster in hatchery conditions than the native ones. We also find a dilution of the impact of this kind of suplementation in wild conditions. The use of only native individuals as hatchery breeders tested for the presence of non-native alleles previously to the artificial crosses must be a priority. Surveys can help steer policy making toward decisions that will be followed by the public, but they should not be used to justify science.

  3. Expansion of Non-Native Brown Trout in South Europe May Be Inadvertently Driven by Stocking: Molecular and Social Survey in the North Iberian Narcea River.

    Science.gov (United States)

    Horreo, Jose L; Abad, David; Dopico, Eduardo; Oberlin, Maud; Garcia-Vazquez, Eva

    2015-01-01

    The biological and anthropogenic (management) factors that may contribute to the expansion of non-native lineages in managed fish have been studied in this work taking brown trout (Salmo trutta) as a model species. The changes of users' opinion about stocking was studied employing social science methodology (surveys). The evolution of hatchery stocks together with the outcome of stocking were analysed with two genetic tools: the LDH-C1* locus (marker of non-native stocks) and six microsatellite loci (for assignment of wild trout to the natural population or putative hatchery stocks). Consulted stakeholders were convinced of the correctness of releasing only native stocks, although in practice the hatcheries managed by them contained important proportions of non-native gene carriers. Our results suggest that allochthonous individuals perform better and grow faster in hatchery conditions than the native ones. We also find a dilution of the impact of this kind of suplementation in wild conditions. The use of only native individuals as hatchery breeders tested for the presence of non-native alleles previously to the artificial crosses must be a priority. Surveys can help steer policy making toward decisions that will be followed by the public, but they should not be used to justify science. PMID:26184162

  4. Age dependence of the accumulation of organochlorine pollutants in brown trout (Salmo trutta) from a remote high mountain lake (Redo, Pyrenees)

    International Nuclear Information System (INIS)

    Polychlorobiphenyls (PCBs), hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB) and DDT were examined in the muscle of brown trout (Salmo trutta) from a high mountain lake located in the Pyrenees (Catalonia, Spain) that was used as a model of these lacustrine environments. Results indicate that fish age is the main factor of variability among specimens in this population that is subjected to atmospheric inputs of the organochlorine compounds (OC). Increases of 2- and 20-fold between fish aged 1 year and 15 years old are found. The observed pattern cannot be explained in terms of fish size, condition factor, or muscle lipid content. Higher molecular weight compounds (higher lipophilicity) are better correlated with fish age than low molecular weight compounds. A transformation from 4,4'-DDT to 4,4'-DDE occurs in fish after ingestion; this results in amplified age-dependent signals, especially in male specimens. In contrast, PCB congener no. 180 has lower age dependence than the general OC group, which could be due to its high hydrophobicity (log Kow > 7). In any case, selective accumulation of hydrophobic compounds is already observed among younger fish (age, 1 year). Due to this effect, the relative OC composition does not reflect the main OC pollutants in the lake waters. - Trout in high mountain lakes display age-dependent accumulation of certain organochlorine pollutants

  5. 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.

  6. Statistical evaluation of the effects of fall and winter flows on the spring condition of rainbow and brown trout in the green river downstream of Flaming Gorge Dam.

    Energy Technology Data Exchange (ETDEWEB)

    Magnusson, A. K.; LaGory, K. E.; Hayse, J. W.; Environmental Science Division

    2009-01-09

    Flaming Gorge Dam, a hydroelectric facility operated by the Bureau of Reclamation (Reclamation), is located on the Green River in Daggett County, northeastern Utah. In recent years, single peak releases each day or steady flows have been the operational pattern during the winter period. A double-peak pattern (two flow peaks each day) was implemented during the winter of 2006-2007 by Reclamation. Because there is no recent history of double-peaking at Flaming Gorge Dam, the potential effects of double-peaking operations on the body condition of trout in the dam's tailwater are not known. A study plan was developed that identified research activities to evaluate potential effects from double-peaking operations during winter months. Along with other tasks, the study plan identified the need to conduct a statistical analysis of existing data on trout condition and macroinvertebrate abundance to evaluate potential effects of hydropower operations. This report presents the results of this analysis. We analyzed historical data to (1) describe temporal patterns and relationships among flows, benthic macroinvertebrate abundance, and condition of brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) in the tailwaters of Flaming Gorge Dam and (2) to evaluate the degree to which flow characteristics (i.e., flow volumes and flow variability) and benthic macroinvertebrate abundance affect the condition of trout in this area. This information, together with further analyses of size-stratified trout data, may also serve as baseline data to which the effects of potential future double-peaking flows can be compared. The condition (length, weight and/or relative weight) of rainbow trout (Oncorhynchus mykiss) at two sites in the Green River downstream of Flaming Gorge Dam (Tailrace and Little Hole) and weight of brown trout (Salmo trutta) at the Little Hole site has been decreasing since 1990 while the abundance of brown trout has been increasing at the two sites. At

  7. Comparative study of CXC chemokines modulation in brown trout (Salmo trutta) following infection with a bacterial or viral pathogen.

    Science.gov (United States)

    Gorgoglione, Bartolomeo; Zahran, Eman; Taylor, Nick G H; Feist, Stephen W; Zou, Jun; Secombes, Christopher J

    2016-03-01

    Chemokine modulation in response to pathogens still needs to be fully characterised in fish, in view of the recently described novel chemokines present. This paper reports the first comparative study of CXC chemokine genes transcription in salmonids (brown trout), with a particular focus on the fish specific CXC chemokines (CXCL_F). Adopting new primer sets, optimised to specifically target mRNA, a RT-qPCR gene screening was carried out. Constitutive gene expression was assessed first in six tissues from SPF brown trout. Transcription modulation was next investigated in kidney and spleen during septicaemic infection induced by a RNA virus (Viral Haemorrhagic Septicaemia virus, genotype Ia) or by a Gram negative bacterium (Yersinia ruckeri, ser. O1/biot. 2). From each target organ specific pathogen burden, measured detecting VHSV-glycoprotein or Y. ruckeri 16S rRNA, and IFN-γ gene expression were analysed for their correlation to chemokine transcription. Both pathogens modulated CXC chemokine gene transcript levels, with marked up-regulation seen in some cases, and with both temporal and tissue specific effects apparent. For example, Y. ruckeri strongly induced chemokine transcription in spleen within 24h, whilst VHS generally induced the largest increases at 3d.p.i. in both tissues. This study gives clues to the role of the novel CXC chemokines, in comparison to the other known CXC chemokines in salmonids. PMID:26866873

  8. Shifts in the suitable habitat available for brown trout (Salmo trutta L.) under short-term climate change scenarios.

    Science.gov (United States)

    Muñoz-Mas, R; Lopez-Nicolas, A; Martínez-Capel, F; Pulido-Velazquez, M

    2016-02-15

    The impact of climate change on the habitat suitability for large brown trout (Salmo trutta L.) was studied in a segment of the Cabriel River (Iberian Peninsula). The future flow and water temperature patterns were simulated at a daily time step with M5 models' trees (NSE of 0.78 and 0.97 respectively) for two short-term scenarios (2011-2040) under the representative concentration pathways (RCP 4.5 and 8.5). An ensemble of five strongly regularized machine learning techniques (generalized additive models, multilayer perceptron ensembles, random forests, support vector machines and fuzzy rule base systems) was used to model the microhabitat suitability (depth, velocity and substrate) during summertime and to evaluate several flows simulated with River2D©. The simulated flow rate and water temperature were combined with the microhabitat assessment to infer bivariate habitat duration curves (BHDCs) under historical conditions and climate change scenarios using either the weighted usable area (WUA) or the Boolean-based suitable area (SA). The forecasts for both scenarios jointly predicted a significant reduction in the flow rate and an increase in water temperature (mean rate of change of ca. -25% and +4% respectively). The five techniques converged on the modelled suitability and habitat preferences; large brown trout selected relatively high flow velocity, large depth and coarse substrate. However, the model developed with support vector machines presented a significantly trimmed output range (max.: 0.38), and thus its predictions were banned from the WUA-based analyses. The BHDCs based on the WUA and the SA broadly matched, indicating an increase in the number of days with less suitable habitat available (WUA and SA) and/or with higher water temperature (trout will endure impoverished environmental conditions ca. 82% of the days). Finally, our results suggested the potential extirpation of the species from the study site during short time spans. PMID:26674698

  9. Differential Accumulation of Mercury and Selenium in Brown Trout Tissues of a High-Gradient Urbanized Stream in Colorado, USA.

    Science.gov (United States)

    Herrmann, S J; Nimmo, D R; Carsella, J S; Herrmann-Hoesing, L M; Turner, J A; Gregorich, J M; Heuvel, B D Vanden; Nehring, R B; Foutz, H P

    2016-02-01

    Total mercury (THg) and selenium (Se) were analyzed by Inductively Coupled Plasma Mass Spectrometry in 11 internal and external tissues and stomach contents from 23 brown trout, Salmo trutta, of a 22.9-km reach of a high-gradient stream (upper Fountain Creek) in Colorado, USA, impacted by coal-fired power plants, shale deposits, and urbanization. Trout and water were sampled from four sites ranging from 2335 to 1818 m elevation. Lengths, weights, and ages of fish between pairs of the four sites were not significantly different. The dry weight (dw) to wet weight (ww) conversion factor for each tissue was calculated with egg-ovary highest at 0.379 and epaxial muscle fourth highest at 0.223. THg and Se in stomach contents indicated diet and not ambient water was the major source of Hg and Se bioaccumulated. Mean THg ww in kidney was 40.33 µg/kg, and epaxial muscle second highest at 36.76 µg/kg. None of the tissues exceeded the human critical threshold for Hg. However, all 23 trout had at least one tissue type that exceeded 0.02 mg/kg THg ww for birds, and four trout tissues exceeded 0.1 mg/kg THg ww for mammals, indicating that piscivorous mammals and birds should be monitored. Se concentrations in tissues varied depending on ww or dw listing. Mean Se dw in liver was higher than ovary at the uppermost site and the two lower sites. Liver tissue, in addition to egg-ovary, should be utilized as an indicator tissue for Se toxicity. PMID:26608694

  10. Toxicokinetics of tetrabromoethylcyclohexane (TBECH) in juvenile brown trout (Salmo trutta) and effects on plasma sex hormones

    International Nuclear Information System (INIS)

    Technical 1,2-dibromo-4-(1,2 dibromoethyl)cyclohexane or tetrabromoethylcyclohexane (TBECH) used primarily as an additive flame retardant in polystyrene foams, contains two diastereoisomers, α- and β- present in equimolar amounts. At temperatures in excess of 125 oC, isomerization to two other isoforms, δ- and γ- is possible. The recent detection of TBECH in the environment and studies suggesting that isomers are androgenic prompted us to examine the toxicokinetics and biochemical effects of one of the isomers, β-, in a controlled laboratory environment. Juvenile brown trout (Salmo trutta) were exposed to three different amounts of the β-isomer (low, medium and high) via the food followed by a period in which they were exposed to unfortified food. A fourth group of fish was exposed to unfortified food for the duration of the experiment. On days 0, 7, 14, 21, 35, 49, 56, 63, 77, 91, 105, and 133, eight fish from each treatment group were euthanized and liver, plasma, lower jaw (i.e., thyroid tissue) and gonad were collected and the remaining tissue ('whole-fish') was retained. β-Isomer content was measured in whole-fish and in liver while estradiol (E2), 11-ketotestosterone (11-KT) and testosterone (T) were measured in plasma. Based on liver and gonad somatic indices, no apparent effects on liver or gonad development in fish from any of the treatment groups were observed. The bioaccumulation of β-isomer was similar in fish from all treatment groups with steady-state occurring before the end of the uptake phase. Depuration of the β-isomer from fish obeyed first order kinetics and there were no statistically significant differences in the depuration half life (t1/2) among the treatment groups: 22.5 ± 10.4 (low), 13.5 ± 5.9 (med) and 13.8 ± 2.2 (high) days. Steady-state biomagnification factors were much smaller than 1 for fish in all treatment groups. Debrominated metabolites were not detected in composite liver or whole-fish extracts and there was no

  11. Toxicokinetics of tetrabromoethylcyclohexane (TBECH) in juvenile brown trout (Salmo trutta) and effects on plasma sex hormones

    Energy Technology Data Exchange (ETDEWEB)

    Gemmill, Bonnie [Fisheries and Oceans Canada, Arctic Aquatic Research Division, Winnipeg, Manitoba R3T 2N6 (Canada); Department of Environment and Geography, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada); Pleskach, Kerri [Fisheries and Oceans Canada, Arctic Aquatic Research Division, Winnipeg, Manitoba R3T 2N6 (Canada); Peters, Lisa [Fisheries and Oceans Canada, Arctic Aquatic Research Division, Winnipeg, Manitoba R3T 2N6 (Canada); Department of Environment and Geography, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada); Palace, Vince [Department of Environment and Geography, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada); Fisheries and Oceans Canada, Environmental Science Division, Winnipeg, Manitoba R3T 2N6 (Canada); Wautier, Kerry; Park, Brad [Fisheries and Oceans Canada, Environmental Science Division, Winnipeg, Manitoba R3T 2N6 (Canada); Darling, Colin; Rosenberg, Bruno [Fisheries and Oceans Canada, Arctic Aquatic Research Division, Winnipeg, Manitoba R3T 2N6 (Canada); McCrindle, Robert [Wellington Laboratories Incorporated, Research Division, Guelph, ON N1G 3M5 (Canada); Tomy, Gregg T., E-mail: gregg.tomy@dfo-mpo.gc.ca [Fisheries and Oceans Canada, Arctic Aquatic Research Division, Winnipeg, Manitoba R3T 2N6 (Canada); Department of Environment and Geography, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada)

    2011-01-25

    Technical 1,2-dibromo-4-(1,2 dibromoethyl)cyclohexane or tetrabromoethylcyclohexane (TBECH) used primarily as an additive flame retardant in polystyrene foams, contains two diastereoisomers, {alpha}- and {beta}- present in equimolar amounts. At temperatures in excess of 125 {sup o}C, isomerization to two other isoforms, {delta}- and {gamma}- is possible. The recent detection of TBECH in the environment and studies suggesting that isomers are androgenic prompted us to examine the toxicokinetics and biochemical effects of one of the isomers, {beta}-, in a controlled laboratory environment. Juvenile brown trout (Salmo trutta) were exposed to three different amounts of the {beta}-isomer (low, medium and high) via the food followed by a period in which they were exposed to unfortified food. A fourth group of fish was exposed to unfortified food for the duration of the experiment. On days 0, 7, 14, 21, 35, 49, 56, 63, 77, 91, 105, and 133, eight fish from each treatment group were euthanized and liver, plasma, lower jaw (i.e., thyroid tissue) and gonad were collected and the remaining tissue ('whole-fish') was retained. {beta}-Isomer content was measured in whole-fish and in liver while estradiol (E2), 11-ketotestosterone (11-KT) and testosterone (T) were measured in plasma. Based on liver and gonad somatic indices, no apparent effects on liver or gonad development in fish from any of the treatment groups were observed. The bioaccumulation of {beta}-isomer was similar in fish from all treatment groups with steady-state occurring before the end of the uptake phase. Depuration of the {beta}-isomer from fish obeyed first order kinetics and there were no statistically significant differences in the depuration half life (t{sub 1/2}) among the treatment groups: 22.5 {+-} 10.4 (low), 13.5 {+-} 5.9 (med) and 13.8 {+-} 2.2 (high) days. Steady-state biomagnification factors were much smaller than 1 for fish in all treatment groups. Debrominated metabolites were not

  12. GROWTH, MORTALITY AND PRODUCTION OF BROWN AND RAINBOW TROUT IN NEW MEXICO STREAMS

    Directory of Open Access Journals (Sweden)

    S Leiner

    1995-06-01

    Full Text Available Thirty-two representative trout sites in 15 high elevation New Mexico streams (1,661 - 2560 m above sea level were sampled in 1988 and 1989. Fish was captured by consecutive removal via electrofishing in net-blocked segments from 65 to 160 m long. Maximum estimated trout length (Lm.ax was related inversely to yield (r2 = 0.351; p = 0.055. Instantaneous rate of mortality was also marginally related to yield (r2 = 0.294. The production index ranged from 1,38 to 32.02 g/m2/year. Variation in production was highly correlated to trout biomass (r2 = 0.910. Trout growth and production were best defined by the relationships where: cover, stream width, water temperature, yield by anglers, LMAX, and nitrate-nitrogen concentration were included.

  13. Future migratory behaviour predicted from premigratory levels of gill Na+/K(+-)ATPase activity in individual wild brown trout ( Salmo trutta )

    DEFF Research Database (Denmark)

    Nielsen, C.; Aarestrup, Kim; Norum, U.;

    2004-01-01

    The relationship between premigratory gill Na+/K(+-)ATPase activity, determined at two dates during spring, and future migratory behaviour was investigated using non-lethal gill biopsies and PIT-tagging in wild brown trout (Salmo trutta) from two tributaries. No significant relationship between......(-1)), with an average of 91 % of the predictions being correct. The present study shows that a non-lethal premigratory biochemical measurement can successfully select individual brown trout with high probability of migration...... obtained. The ability of this regression model from the tributaries to predict future migratory behaviour in an independent group of trout caught in early April in the mainstream was evaluated. A threshold probability of migration was used to predict the behaviour of the mainstream individuals as either...

  14. Physiological effects of simultaneous, abrupt seawater entry and sea lice (Lepeophtheirus salmonis) infestation of wild, sea-run brown trout (Salmo trutta) smolts

    NARCIS (Netherlands)

    Wells, A.; Grierson, C.E.; MacKenzie, M.; Russon, I.; Middlemiss, C.; Bjorn, P.A.; Finstad, B.; Wendelaar Bonga, S.E.; Todd, C.D.; Hazon, N.

    2006-01-01

    For wild, sea-run brown trout (Salmo trutta) smolts, the physiological consequences of abrupt transfer to seawater and simultaneous challenge with copepodid larvae of the sea louse, Lepeophtheirus salmonis (Krøyer, 1837), were investigated in the laboratory. Analysis of osmoregulatory, metabolic, an

  15. Forest-stream linkages: effects of terrestrial invertebrate input and light on diet and growth of brown trout (Salmo trutta in a boreal forest stream.

    Directory of Open Access Journals (Sweden)

    Tibor Erős

    Full Text Available Subsidies of energy and material from the riparian zone have large impacts on recipient stream habitats. Human-induced changes, such as deforestation, may profoundly affect these pathways. However, the strength of individual factors on stream ecosystems is poorly understood since the factors involved often interact in complex ways. We isolated two of these factors, manipulating the flux of terrestrial input and the intensity of light in a 2×2 factorial design, where we followed the growth and diet of two size-classes of brown trout (Salmo trutta and the development of periphyton, grazer macroinvertebrates, terrestrial invertebrate inputs, and drift in twelve 20 m long enclosed stream reaches in a five-month-long experiment in a boreal coniferous forest stream. We found that light intensity, which was artificially increased 2.5 times above ambient levels, had an effect on grazer density, but no detectable effect on chlorophyll a biomass. We also found a seasonal effect on the amount of drift and that the reduction of terrestrial prey input, accomplished by covering enclosures with transparent plastic, had a negative impact on the amount of terrestrial invertebrates in the drift. Further, trout growth was strongly seasonal and followed the same pattern as drift biomass, and the reduction of terrestrial prey input had a negative effect on trout growth. Diet analysis was consistent with growth differences, showing that trout in open enclosures consumed relatively more terrestrial prey in summer than trout living in covered enclosures. We also predicted ontogenetic differences in the diet and growth of old and young trout, where we expected old fish to be more affected by the terrestrial prey reduction, but we found little evidence of ontogenetic differences. Overall, our results showed that reduced terrestrial prey inputs, as would be expected from forest harvesting, shaped differences in the growth and diet of the top predator, brown trout.

  16. The effects of overwinter flowson the spring condition of rainbow and brown trout size classes in the Green River downstream of Flaming Gorge Dam, Utah.

    Energy Technology Data Exchange (ETDEWEB)

    Magnusson, A. K.; LaGory, K. E.; Hayse, J. W.; Environmental Science Division

    2010-06-25

    Flaming Gorge Dam, a hydroelectric facility operated by the Bureau of Reclamation (Reclamation), is located on the Green River in Daggett County, northeastern Utah. Until recently, and since the early 1990s, single daily peak releases or steady flows have been the operational pattern of the dam during the winter period. However, releases from Flaming Gorge Reservoir followed a double-peak pattern (two daily flow peaks) during the winters of 2006-2007 and 2008-2009. Because there is little recent long-term history of double-peaking at Flaming Gorge Dam, the potential effects of double-peaking operations on trout body condition in the dam's tailwater are not known. A study plan was developed that identified research activities to evaluate potential effects from winter double-peaking operations (Hayse et al. 2009). Along with other tasks, the study plan identified the need to conduct a statistical analysis of historical trout condition and macroinvertebrate abundance to evaluate the potential effects of hydropower operations. The results from analyses based on the combined size classes of trout (85-630 mm) were presented in Magnusson et al. (2008). The results of this earlier analysis suggested possible relationships between trout condition and flow, but concern that some of the relationships resulted from size-based effects (e.g., apparent changes in condition may have been related to concomitant changes in size distribution, because small trout may have responded differently to flow than large trout) prompted additional analysis of within-size class relationships. This report presents the results of analyses of three different size classes of trout (small: 200-299 mm, medium: 300-399 mm, and large: {ge}400 mm body length). We analyzed historical data to (1) describe temporal patterns and relationships among flows, benthic macroinvertebrate abundance, and condition of brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) in the tailwaters of Flaming

  17. The relationship between young brown trout density and water quality in tributary streams to lakes in three acidic watersheds; Effekter av vannkvalitet og habitat paa tettheten av aureunger i tilloepsbekker til innsjoeer i tre forsuringsomraader

    Energy Technology Data Exchange (ETDEWEB)

    Hesthagen, Trygve; Larsen, Bjoern M.; Berger, Hans M.; Forseth, Torbjoern

    1998-09-01

    This publication examines the relationship between young brown trout densities in lake tributaries, and water chemistry and habitat variables. The study was carried out during the autumn in three acidic, freshwater river systems in western and southwestern Norway. The variability in brown trout density in the three watersheds in relation to varying concentrations of calcium and inorganic Al, were investigated. Water chemistry variables seem to limit the density. 38 refs., 3 figs., 5 tabs.

  18. The abiotic environment of the interstitial of a small Swiss river in the foothills of the Alps and its influence on gravel spawning brown trout (Salmo trutta L.)

    Science.gov (United States)

    Schindler, Yael; Michel, Christian; Holm, Patricia; Alewell, Christine

    2010-05-01

    The hyporheic zone can be characterized by multiple abiotic parameters (e.g. bulk density, texture, temperature, oxygen, ammonium, nitrate) which are all influenced directly or indirectly by the exchange processes between surface water and groundwater. These processes can vary both in time and space and are mainly driven by river discharge, ground water level and flow patterns. The input of fine sediment particles can change water-riverbed interactions through river bed clogging potentially affecting the embryonal development and survival of gravel spawning fish, such as brown trout (Salmo trutta L.). With our investigations we aim to understand these complex interactions spatially and temporally on a relevant small scale, i.e. within individual artificial brown trout redds. We designed an experimental field setup to directly investigate i) the influence of the abiotic river and redd environment on brown trout embryo development and ii) the hydrological dynamics affecting the abiotic environment in artificial brown trout. Additionally, our setup allows investigating the temporal dynamics of i) fine-sediment infiltration into the artificial redds and ii) embryo survival to two distinct developmental stages (i.e. eyed stage and hatch) The experiment was conducted in three sites of a typical Swiss river (Enziwigger, Canton of Luzern) with a strongly modified morphology. Individual sites represented a high, medium and low fine-sediment load. In each site, six artificial redds (18 in total) were built and data were collected during the entire incubation phase. Redds were located in places where natural spawning of brown trout is present. We adapted multiple established methods to the smaller scale of our river to study the dynamics of the most relevant abiotic parameters potentially affecting embryo development: Oxygen content and temperature was monitored continuously in different depths, fine sediment (bedload, suspended sediment load and its input in the river bed

  19. Measurement of total Zn and Zn isotope ratios by quadrupole ICP-MS for evaluation of Zn uptake in gills of brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss)

    Science.gov (United States)

    Wolf, R.E.; Todd, A.S.; Brinkman, S.; Lamothe, P.J.; Smith, K.S.; Ranville, J.F.

    2009-01-01

    This study evaluates the potential use of stable zinc isotopes in toxicity studies measuring zinc uptake by the gills of brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss). The use of stable isotopes in such studies has several advantages over the use of radioisotopes, including cost, ease of handling, elimination of permit requirements, and waste disposal. A pilot study using brown trout was performed to evaluate sample preparation methods and the ability of a quadrupole inductively coupled plasma mass spectrometer (ICP-MS) system to successfully measure changes in the 67Zn/66Zn ratios for planned exposure levels and duration. After completion of the pilot study, a full-scale zinc exposure study using rainbow trout was performed. The results of these studies indicate that there are several factors that affect the precision of the measured 67Zn/66Zn ratios in the sample digests, including variations in sample size, endogenous zinc levels, and zinc uptake rates by individual fish. However, since these factors were incorporated in the calculation of the total zinc accumulated by the gills during the exposures, the data obtained were adequate for their intended use in calculating zinc binding and evaluating the influences of differences in water quality parameters.

  20. Epitheliocystis Distribution and Characterization in Brown Trout (Salmo trutta) from the Headwaters of Two Major European Rivers, the Rhine and Rhone.

    Science.gov (United States)

    Guevara Soto, Maricruz; Vaughan, Lloyd; Segner, Helmut; Wahli, Thomas; Vidondo, Beatriz; Schmidt-Posthaus, Heike

    2016-01-01

    We present a first description of the distribution and characterization of epitheliocystis infections in brown trout (Salmo trutta) from the upper catchments of two major European rivers, the Rhine and the Rhone. Overall, epitheliocystis was widely distributed, with 70% of the Rhine and 67% of the Rhone sites harboring epitheliocystis positive brown trout. The epitheliocystis agents Candidatus Piscichlamydia salmonis and Candidatus Clavichlamydia salmonicola could be identified in both catchments, although their relative proportions differed from site to site. Additionally, in two rivers in the Rhine catchment, a new species of Candidatus Similichlamydia was identified. Based on the histology, infection intensity, and severity of pathological changes were significantly more pronounced in mixed chlamydial infections, whereas single infections showed only low numbers of cysts and mild pathology. Infections could be found over a wide range of temperatures, which showed no correlation to infection prevalence or intensity. PMID:27148070

  1. Time-course changes in the expression of Na+, K+-ATPase in gills and pyloric caeca of brown trout (Salmo trutta) during acclimation to seawater

    DEFF Research Database (Denmark)

    Seidelin, Michel; Madsen, Steffen; Blenstrup, Henrik;

    2000-01-01

    Changes in protein and mRNA expression of Na+,K+-ATPase in gills and pyloric caeca of brown trout were investigated on a detailed time course after transfer from freshwater to 25 ppt seawater (SW). A transient deflection in plasma osmolality and muscle water content lasting from 4 h until day 3...... posttransfer. The similarity of the response in these two organs suggests that they both play significant physiological roles in restoring hydromineral balance after abrupt increase in salinity. Further, SW transfer induced a slight, though significant, increase in primary gill filament Na+, K......+-ATPase immunoreactive (NKIR) cell abundance. This was paralleled by a marked (50%) decrease in secondary lamellar NKIR cell abundance after less than 1 d in SW. Thus, SW acclimation in brown trout is characterised by a lasting decrease in overall NKIR cell abundance in the gill. We propose that SW transfer stimulates...

  2. 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...

  3. Feeding Habits and Diet Composition of Brown Trout (Salmo trutta) in the Upper Streams of River Ceyhan and River Euphrates in Turkey

    OpenAIRE

    Kara, Cemil

    2005-01-01

    The feeding habits and diet composition of the stream dwelling resident brown trout Salmo trutta in the upper streams of River Ceyhan and River Euphrates were investigated by examining the stomach contents of 611 specimens collected from May 2000 to April 2001. Analysis of monthly variations of stomach fullness indicated that feeding intensity was higher between February and June than that for the spawning season that covered the period from November to January. A total of 42 prey taxa repres...

  4. SUPPLEMENTAL STOCKING OF EYED BROWN TROUT EGGS (SALMO TRUTTA M. FARIO L., 1758 WITH THE USE OF WHITLOCK–VIBERT BOXES

    Directory of Open Access Journals (Sweden)

    Manuela Turković

    2006-07-01

    Full Text Available The research was carried out in the Upper Kupa valley at three different locations–brooks, Lešnički potok, Lešnički jarak and Grčac. During the research efficiency of stocking with Whitlock Vibert boxes were studied. During the three month research period (January 2005 — April 2005 4000 eyed brown trout eggs from 3 different sources were placed in 14 Whitlock–Vibert boxes. During the research resultes from Grčac brook were excluded from the final analysis of efficiency of Whitlock–Vibert boxes because of technical problems, so resultes for the final analysis were used from 2800 eyed brown trout eggs that were placed in 10 Whitlock–Vibert boxes where 99,53% of the eggs had successfully hatched. The results have shown that the use of Whitlock–Vibert boxes with eyed brown trout eggs is prosperous and that the efficiency of Whitlock–Vibert boxes depends on the quality of eggs and choice of box burial in the stream bed. The research was conducted in the context of the regular management obligations of the fishing right owner on the research area.

  5. Cytochrome P4501A induction in brown trout exposed to small streams of an urbanised area: results of a five-year-study

    International Nuclear Information System (INIS)

    This case study examines the ability of the cytochrome P4501A (CYP1A) biomarker to distinguish the pollution status of two small streams, Kraehenbach and Koersch, receiving different levels of urban and agricultural impact, with low to moderate contamination by arylhydrocarbon receptor (AhR)-binding PAHs and PCBs. Brown trout, Salmo trutta, exposed in enclosure restrictions, showed significant between-stream differences of hepatic CYP1A levels. EROD activities were the better discriminator than CYP1A protein levels. The CYP1A response was consistent and repeatable over the 5-year observation period from 1995 to 1999. In contrast to brown trout, hepatic CYP1A of stone loach, Barbatula barbatula, did not clearly distinguish the streams. The findings of this long-term study lend support to the use of CYP1A as a biomarker of degraded environmental conditions, provided that sufficiently long observation periods are used to average out confounding factors, that sufficiently sensitive detection methods are used, and that a responsive monitoring species is chosen. - The CYP1A biomarker in brown trout robustly ranks the chemical stress status of small streams

  6. 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.

  7. Local variability mediates vulnerability of trout populations to land use and climate change

    Science.gov (United States)

    Penaluna, Brooke E.; Dunham, Jason B.; Railsback, Steve F.; Arismendi, Ivan; Johnson, Sherri L.; Bilby, Robert E; Safeeq, Mohammad; Skaugset, Arne E.

    2015-01-01

    Land use and climate change occur simultaneously around the globe. Fully understanding their separate and combined effects requires a mechanistic understanding at the local scale where their effects are ultimately realized. Here we applied an individual-based model of fish population dynamics to evaluate the role of local stream variability in modifying responses of Coastal Cutthroat Trout (Oncorhynchus clarkii clarkii) to scenarios simulating identical changes in temperature and stream flows linked to forest harvest, climate change, and their combined effects over six decades. We parameterized the model for four neighboring streams located in a forested headwater catchment in northwestern Oregon, USA with multi-year, daily measurements of stream temperature, flow, and turbidity (2007–2011), and field measurements of both instream habitat structure and three years of annual trout population estimates. Model simulations revealed that variability in habitat conditions among streams (depth, available habitat) mediated the effects of forest harvest and climate change. Net effects for most simulated trout responses were different from or less than the sum of their separate scenarios. In some cases, forest harvest countered the effects of climate change through increased summer flow. Climate change most strongly influenced trout (earlier fry emergence, reductions in biomass of older trout, increased biomass of young-of-year), but these changes did not consistently translate into reductions in biomass over time. Forest harvest, in contrast, produced fewer and less consistent responses in trout. Earlier fry emergence driven by climate change was the most consistent simulated response, whereas survival, growth, and biomass were inconsistent. Overall our findings indicate a host of local processes can strongly influence how populations respond to broad scale effects of land use and climate change.

  8. Local Variability Mediates Vulnerability of Trout Populations to Land Use and Climate Change.

    Science.gov (United States)

    Penaluna, Brooke E; Dunham, Jason B; Railsback, Steve F; Arismendi, Ivan; Johnson, Sherri L; Bilby, Robert E; Safeeq, Mohammad; Skaugset, Arne E

    2015-01-01

    Land use and climate change occur simultaneously around the globe. Fully understanding their separate and combined effects requires a mechanistic understanding at the local scale where their effects are ultimately realized. Here we applied an individual-based model of fish population dynamics to evaluate the role of local stream variability in modifying responses of Coastal Cutthroat Trout (Oncorhynchus clarkii clarkii) to scenarios simulating identical changes in temperature and stream flows linked to forest harvest, climate change, and their combined effects over six decades. We parameterized the model for four neighboring streams located in a forested headwater catchment in northwestern Oregon, USA with multi-year, daily measurements of stream temperature, flow, and turbidity (2007-2011), and field measurements of both instream habitat structure and three years of annual trout population estimates. Model simulations revealed that variability in habitat conditions among streams (depth, available habitat) mediated the effects of forest harvest and climate change. Net effects for most simulated trout responses were different from or less than the sum of their separate scenarios. In some cases, forest harvest countered the effects of climate change through increased summer flow. Climate change most strongly influenced trout (earlier fry emergence, reductions in biomass of older trout, increased biomass of young-of-year), but these changes did not consistently translate into reductions in biomass over time. Forest harvest, in contrast, produced fewer and less consistent responses in trout. Earlier fry emergence driven by climate change was the most consistent simulated response, whereas survival, growth, and biomass were inconsistent. Overall our findings indicate a host of local processes can strongly influence how populations respond to broad scale effects of land use and climate change.

  9. Application of a generalized linear mixed model to analyze mixture toxicity: survival of brown trout affected by copper and zinc.

    Science.gov (United States)

    Iwasaki, Yuichi; Brinkman, Stephen F

    2015-04-01

    Increased concerns about the toxicity of chemical mixtures have led to greater emphasis on analyzing the interactions among the mixture components based on observed effects. The authors applied a generalized linear mixed model (GLMM) to analyze survival of brown trout (Salmo trutta) acutely exposed to metal mixtures that contained copper and zinc. Compared with dominant conventional approaches based on an assumption of concentration addition and the concentration of a chemical that causes x% effect (ECx), the GLMM approach has 2 major advantages. First, binary response variables such as survival can be modeled without any transformations, and thus sample size can be taken into consideration. Second, the importance of the chemical interaction can be tested in a simple statistical manner. Through this application, the authors investigated whether the estimated concentration of the 2 metals binding to humic acid, which is assumed to be a proxy of nonspecific biotic ligand sites, provided a better prediction of survival effects than dissolved and free-ion concentrations of metals. The results suggest that the estimated concentration of metals binding to humic acid is a better predictor of survival effects, and thus the metal competition at the ligands could be an important mechanism responsible for effects of metal mixtures. Application of the GLMM (and the generalized linear model) presents an alternative or complementary approach to analyzing mixture toxicity. PMID:25524054

  10. Effects of hydropeaking on the spawning behaviour of Atlantic salmon Salmo salar and brown trout Salmo trutta.

    Science.gov (United States)

    Vollset, K W; Skoglund, H; Wiers, T; Barlaup, B T

    2016-06-01

    An in situ camera set-up was used to study the spawning activity of Atlantic salmon Salmo salar and brown trout Salmo trutta throughout two consecutive seasons in a spawning area affected by hydropower-related pulse flows due to hydropeaking. The purpose was to test whether the flow variation discouraged spawning in shallow areas or motivated spawning into areas with elevated risk of incubation mortality. There were more S. salar observed on the spawning ground during days with high discharge. The presence of S. salar in the spawning grounds was not affected by the hydropeaking cycles of the preceding night. Female S. salar were observed preparing nests within the first hour after water discharge had increased to levels suitable for spawning. In contrast, the number of S. trutta was not correlated with flow and nest preparation was also observed at a discharge corresponding to the lowest discharge levels during a hydropeaking cycle. Survival was generally high in nests excavated the following winter, with only 5·4% suffering mortality due to dewatering. The results suggest that S. salar may respond rapidly to variable-flow conditions and utilize short windows with suitable flows for spawning. Smaller S. trutta may utilize low-flow conditions to spawn in areas that are not habitable by larger S. salar during low flow. PMID:27125209

  11. 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.

  12. Examining indirect effects of lake trout recovery

    Science.gov (United States)

    With the recovery of lake trout populations in Lake Superior, there are indications of decreased forage fish abundance and density-dependence in lake trout. In Lake Superior, lean lake trout historically occupied depths trout occupied depths > 60 m...

  13. Behavioral avoidance: Possible mechanism for explaining abundance and distribution of trout species in a metal-impacted river

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, J.A.; Bergman, H.L. [Univ. of Wyoming, Laramie, WY (United States); Woodward, D.F. [Geological Survey, Jackson, WY (United States). Environmental and Contaminants Research Center; Little, E.E.; DeLonay, A.J. [Geological Survey, Columbia, MO (United States). Environmental and Contaminants Research Center

    1999-02-01

    Behavioral avoidance of metal mixtures by rainbow trout (Oncorhynchus mykiss) was determined in the laboratory under water quality conditions that simulated the upper Clark Fork River, Montana, USA. A metal mixture with a fixed ratio of observed ambient metal concentrations (12 {micro}g/L Cu:1.1 {micro}g/L Cd:3.2 {micro}g/L Pb:50 {micro}g/L Zn) was used to determine avoidance in a countercurrent avoidance chamber. Rainbow trout avoided all metal concentrations tested from 10 to 1,000% of the simulated ambient metal mixture. The behavioral response of rainbow trout to the metal mixture was more sensitive than the response of brown trout (Salmo trutta) previously reported from the same laboratory under the same experimental conditions. Additionally, rainbow trout that were acclimated to the simulated ambient metal mixture for 45 d preferred clean water and avoided higher metal concentrations. Therefore, laboratory experiments on the behavioral avoidance responses of rainbow trout, as well as previously reported experiments on brown trout, show that both species will avoid typical metal concentrations observed on the Clark Fork River. And the greater sensitivity of rainbow trout to the metal mixture may explain, in part, why rainbow trout populations appear to be more severely affected, compared to brown trout populations, in the upper Clark Fork River.

  14. Behavioral avoidance: Possible mechanism for explaining abundance and distribution of trout species in a metal-impacted river

    Science.gov (United States)

    Hansen, J.A.; Woodward, D.F.; Little, E.E.; DeLonay, A.J.; Bergman, H.L.

    1999-01-01

    Behavioral avoidance of metal mixtures by rainbow trout (Oncorhynchus mykiss) was determined in the laboratory under water quality conditions that simulated the upper Clark Fork River, Montana, USA. A metal mixture with a fixed ratio of observed ambient metal concentrations (12 mg/L Cu: 1.1 ??g/L Cd:3.2 ??g/L Pb:50 ??g/L Zn) was used to determine avoidance in a countercurrent avoidance chamber. Rainbow trout avoided all metal concentrations tested from 10 to 1,000% of the simulated ambient metal mixture. The behavioral response of rainbow trout to the metal mixture was more sensitive than the response of brown trout (Salmo trutta) previously reported from the same laboratory under the same experimental conditions. Additionally, rainbow trout that were acclimated to the simulated ambient metal mixture for 45 d preferred clean water and avoided higher metal concentrations. Therefore, our laboratory experiments on the behavioral avoidance responses of rainbow trout, as well as previously reported experiments on brown trout, show that both species will avoid typical metal concentrations observed on the Clark Fork River. And the greater sensitivity of rainbow trout to the metal mixture may explain, in part, why rainbow trout populations appear to be more severely affected, compared to brown trout populations; in the upper Clark Fork River.

  15. Temporal clumping of prey and coexistence of unequal interferers: experiments on social forager groups of brown trout feeding on invertebrate drift

    DEFF Research Database (Denmark)

    Jonsson, Mikael; Skov, Christian; Koed, Anders;

    2008-01-01

    Environmental fluctuations have been proposed to enhance the coexistence of competing phenotypes. Evaluations are here presented on the effects of prey density and short-term temporal clumping of prey availability on the relative foraging success of unequal interferers in social forager groups...... of juvenile brown trout Salmo trutta feeding on drifting invertebrate prey (frozen chironomids). Groups of three trout with established linear dominance hierarchies (dominant, intermediate and subordinate) were subjected to three different total numbers of prey, combined with three different levels...... of temporal clumping of prey arrival, resulting in nine treatment combinations. Higher total number of prey increased the consumption for all dominance ranks, while higher temporal clumping decreased the consumption for the dominant individuals and increased the consumption for the subordinate individuals...

  16. Genetic variation underlying resistance to infectious hematopoietic necrosis virus in a steelhead trout (Oncorhynchus mykiss) population

    Science.gov (United States)

    Brieuc, Marine S. O.; Purcell, Maureen K.; Palmer, Alexander D.; Naish, Kerry A.

    2015-01-01

    Understanding the mechanisms of host resistance to pathogens will allow insights into the response of wild populations to the emergence of new pathogens. Infectious hematopoietic necrosis virus (IHNV) is endemic to the Pacific Northwest and infectious to Pacific salmon and trout (Oncorhynchus spp.). Emergence of the M genogroup of IHNV in steelhead trout O. mykiss in the coastal streams of Washington State, between 2007 and 2011, was geographically heterogeneous. Differences in host resistance due to genetic change were hypothesized to be a factor influencing the IHNV emergence patterns. For example, juvenile steelhead trout losses at the Quinault National Fish Hatchery (QNFH) were much lower than those at a nearby facility that cultures a stock originally derived from the same source population. Using a classical quantitative genetic approach, we determined the potential for the QNFH steelhead trout population to respond to selection caused by the pathogen, by estimating the heritability for 2 traits indicative of IHNV resistance, mortality (h2 = 0.377 (0.226 - 0.550)) and days to death (h2 = 0.093 (0.018 - 0.203)). These results confirm that there is a genetic basis for resistance and that this population has the potential to adapt to IHNV. Additionally, genetic correlation between days to death and fish length suggests a correlated response in these traits to selection. Reduction of genetic variation, as well as the presence or absence of resistant alleles, could affect the ability of populations to adapt to the pathogen. Identification of the genetic basis for IHNV resistance could allow the assessment of the susceptibility of other steelhead populations.

  17. 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.

  18. Population response to habitat fragmentation in a stream-dwelling brook trout population

    Science.gov (United States)

    Letcher, B.H.; Nislow, K.H.; Coombs, J.A.; O'Donnell, M. J.; Dubreuil, T.L.

    2007-01-01

    Fragmentation can strongly influence population persistence and expression of life-history strategies in spatially-structured populations. In this study, we directly estimated size-specific dispersal, growth, and survival of stream-dwelling brook trout in a stream network with connected and naturally-isolated tributaries. We used multiple-generation, individual-based data to develop and parameterize a size-class and location-based population projection model, allowing us to test effects of fragmentation on population dynamics at local (i.e., subpopulation) and system-wide (i.e., metapopulation) scales, and to identify demographic rates which influence the persistence of isolated and fragmented populations. In the naturally-isolated tributary, persistence was associated with higher early juvenile survival (-45% greater), shorter generation time (one-half) and strong selection against large body size compared to the open system, resulting in a stage-distribution skewed towards younger, smaller fish. Simulating barriers to upstream migration into two currently-connected tribuory populations caused rapid (2-6 generations) local extinction. These local extinctions in turn increased the likelihood of system-wide extinction, as tributaries could no longer function as population sources. Extinction could be prevented in the open system if sufficient immigrants from downstream areas were available, but the influx of individuals necessary to counteract fragmentation effects was high (7-46% of the total population annually). In the absence of sufficient immigration, a demographic change (higher early survival characteristic of the isolated tributary) was also sufficient to rescue the population from fragmentation, suggesting that the observed differences in size distributions between the naturally-isolated and open system may reflect an evolutionary response to isolation. Combined with strong genetic divergence between the isolated tributary and open system, these results

  19. Assessing Nutritional Parameters of Brown Bear Diets among Ecosystems Gives Insight into Differences among Populations.

    Directory of Open Access Journals (Sweden)

    Claudia López-Alfaro

    Full Text Available Food habit studies are among the first steps used to understand wildlife-habitat relationships. However, these studies are in themselves insufficient to understand differences in population productivity and life histories, because they do not provide a direct measure of the energetic value or nutritional composition of the complete diet. Here, we developed a dynamic model integrating food habits and nutritional information to assess nutritional parameters of brown bear (Ursus arctos diets among three interior ecosystems of North America. Specifically, we estimate the average amount of digestible energy and protein (per kilogram fresh diet content in the diet and across the active season by bears living in western Alberta, the Flathead River (FR drainage of southeast British Columbia, and the Greater Yellowstone Ecosystem (GYE. As well, we estimate the proportion of energy and protein in the diet contributed by different food items, thereby highlighting important food resources in each ecosystem. Bear diets in Alberta had the lowest levels of digestible protein and energy through all seasons, which might help explain the low reproductive rates of this population. The FR diet had protein levels similar to the recent male diet in the GYE during spring, but energy levels were lower during late summer and fall. Historic and recent diets in GYE had the most energy and protein, which is consistent with their larger body sizes and higher population productivity. However, a recent decrease in consumption of trout (Oncorhynchus clarki, whitebark pine nuts (Pinus albicaulis, and ungulates, particularly elk (Cervus elaphus, in GYE bears has decreased the energy and protein content of their diet. The patterns observed suggest that bear body size and population densities are influenced by seasonal availability of protein an energy, likely due in part to nutritional influences on mass gain and reproductive success.

  20. Assessing Nutritional Parameters of Brown Bear Diets among Ecosystems Gives Insight into Differences among Populations.

    Science.gov (United States)

    López-Alfaro, Claudia; Coogan, Sean C P; Robbins, Charles T; Fortin, Jennifer K; Nielsen, Scott E

    2015-01-01

    Food habit studies are among the first steps used to understand wildlife-habitat relationships. However, these studies are in themselves insufficient to understand differences in population productivity and life histories, because they do not provide a direct measure of the energetic value or nutritional composition of the complete diet. Here, we developed a dynamic model integrating food habits and nutritional information to assess nutritional parameters of brown bear (Ursus arctos) diets among three interior ecosystems of North America. Specifically, we estimate the average amount of digestible energy and protein (per kilogram fresh diet) content in the diet and across the active season by bears living in western Alberta, the Flathead River (FR) drainage of southeast British Columbia, and the Greater Yellowstone Ecosystem (GYE). As well, we estimate the proportion of energy and protein in the diet contributed by different food items, thereby highlighting important food resources in each ecosystem. Bear diets in Alberta had the lowest levels of digestible protein and energy through all seasons, which might help explain the low reproductive rates of this population. The FR diet had protein levels similar to the recent male diet in the GYE during spring, but energy levels were lower during late summer and fall. Historic and recent diets in GYE had the most energy and protein, which is consistent with their larger body sizes and higher population productivity. However, a recent decrease in consumption of trout (Oncorhynchus clarki), whitebark pine nuts (Pinus albicaulis), and ungulates, particularly elk (Cervus elaphus), in GYE bears has decreased the energy and protein content of their diet. The patterns observed suggest that bear body size and population densities are influenced by seasonal availability of protein an energy, likely due in part to nutritional influences on mass gain and reproductive success.

  1. Interactions between European minnow (Phoxinus phoxinus) and brown trout (Salmo trutta) in a subalpine lake 40 years after the minnow establishment.

    OpenAIRE

    Iversen, Elisabeth

    2011-01-01

    The aim of this study is to clarify the interaction between European minnow (Phoxinus phoxinus) and brown trout (Salmo trutta), in the subalpine lake, Øvre Heimdalsvatn, with special emphasis on habitat use and diet between the two species about 40 years after the establishment of minnows in the lake. The fieldwork was carried out in three periods: June-July, July-August and August-September 2009. Nordic gillnets were used for collecting fish and to study the habitat use at four different dep...

  2. The effects of chronic cadmium exposure on repeat swimming performance and anaerobic metabolism in brown trout (Salmo trutta) and lake whitefish (Coregonus clupeaformis).

    Science.gov (United States)

    Cunningham, Jessie L; McGeer, James C

    2016-04-01

    This study investigates the effect of chronic Cd exposure on the ability to perform repeat swim challenges in brown trout (Salmo trutta) and lake whitefish (Coregonus clupeaformis). Fish were exposed to waterborne Cd (18nM) in moderately hard water (120mgL(-1) CaCO3) for 30 days. This level of exposure has been shown to cause sublethal physiological disruption and acclimation responses but no impairment of sustained swimming capacity (Ucrit) in single swim challenges. Swim trials were done over the course of the exposure and each one consisted of an initial swim to 85% of the Ucrit of control fish, a 30min recovery period and finally a second swim challenge to determine Ucrit. Plasma and tissue samples were collected before and after each of the swim periods. As expected from previous studies, Cd exposure resulted in significant accumulation of Cd in gills, liver and kidney but not in white muscle. Exposure also induced a loss of plasma Ca followed by subsequent recovery (in lake whitefish but not brown trout) with few mortalities (100% survival for lake whitefish and 93% for brown trout). Both control and exposed fish swam to 85% of the single swim Ucrit and no differences in performance were seen. The Ucrit of unexposed controls in the second swim challenges were not different from the single swim Ucrit. However, second swim performance was significantly reduced in Cd exposed fish, particularly after a week of exposure where 31% and 38% reductions were observed for brown trout and lake whitefish respectively. Swimming to 85% Ucrit resulted in metabolic expenditure with little recovery after 30min. Few differences were observed between control and Cd exposed fish with the exception of a reduction in resting white muscle ATP stores of Cd exposed fish after 1 week of exposure. The results show that chronic sublethal Cd exposure results in an impairment of swimming ability in repeat swim challenges but this impairment is generally not related to metabolic processes

  3. The effects of chronic cadmium exposure on repeat swimming performance and anaerobic metabolism in brown trout (Salmo trutta) and lake whitefish (Coregonus clupeaformis).

    Science.gov (United States)

    Cunningham, Jessie L; McGeer, James C

    2016-04-01

    This study investigates the effect of chronic Cd exposure on the ability to perform repeat swim challenges in brown trout (Salmo trutta) and lake whitefish (Coregonus clupeaformis). Fish were exposed to waterborne Cd (18nM) in moderately hard water (120mgL(-1) CaCO3) for 30 days. This level of exposure has been shown to cause sublethal physiological disruption and acclimation responses but no impairment of sustained swimming capacity (Ucrit) in single swim challenges. Swim trials were done over the course of the exposure and each one consisted of an initial swim to 85% of the Ucrit of control fish, a 30min recovery period and finally a second swim challenge to determine Ucrit. Plasma and tissue samples were collected before and after each of the swim periods. As expected from previous studies, Cd exposure resulted in significant accumulation of Cd in gills, liver and kidney but not in white muscle. Exposure also induced a loss of plasma Ca followed by subsequent recovery (in lake whitefish but not brown trout) with few mortalities (100% survival for lake whitefish and 93% for brown trout). Both control and exposed fish swam to 85% of the single swim Ucrit and no differences in performance were seen. The Ucrit of unexposed controls in the second swim challenges were not different from the single swim Ucrit. However, second swim performance was significantly reduced in Cd exposed fish, particularly after a week of exposure where 31% and 38% reductions were observed for brown trout and lake whitefish respectively. Swimming to 85% Ucrit resulted in metabolic expenditure with little recovery after 30min. Few differences were observed between control and Cd exposed fish with the exception of a reduction in resting white muscle ATP stores of Cd exposed fish after 1 week of exposure. The results show that chronic sublethal Cd exposure results in an impairment of swimming ability in repeat swim challenges but this impairment is generally not related to metabolic processes

  4. Local adaptation in brown trout early life-history traits: implications for climate change adaptability

    DEFF Research Database (Denmark)

    Jensen, L.F.; Hansen, Michael Møller; Pertoldi, C.;

    2008-01-01

      Knowledge of local adaptation and adaptive potential of natural populations is becoming increasingly relevant due to anthropogenic changes in the environment, such as climate change. The concern is that populations will be negatively affected by increasing temperatures without the capacity...... and heritable variation in phenotypic plasticity suggest that although increasing temperatures are likely to affect some populations negatively, they may have the potential to adapt to changing temperature regimes.  ...

  5. Genetic monitoring of supportive breeding in brown trout ( Salmo trutta L.), using microsatellite DNA markers

    DEFF Research Database (Denmark)

    Hansen, Michael Møller; Eg Nielsen, Einar; Ruzzante, D.E.;

    2000-01-01

    reference population. Three different statistical procedures were used to detect population bottlenecks and loss of variability: (i) a randomization test for comparing allelic diversity between samples; (ii) estimates of effective number of breeders from gametic-phase disequilibrium; and (iii) a test...... for assessing population bottlenecks based on detecting deviations from mutation-drift equilibrium. All three procedures were useful but they also exhibited different strengths and limitations, with the test for population bottlenecks probably being the single most useful procedure for routine monitoring...

  6. 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.

  7. The Effects of Florfenicol on the Values of Serum Tumor Necrosis Factor-α and Other Biochemical Markers in Lipopolysaccharide-Induced Endotoxemia in Brown Trout

    Directory of Open Access Journals (Sweden)

    Ayse Er

    2014-01-01

    Full Text Available The aim of the present study was to determine the effects of florfenicol on the expected changes in sTNF-α, damage markers of the liver and kidney, and the lipid metabolism parameters in endotoxemic brown trout. Ninety-six brown trout were included in this study. After six of the fish were reserved as the control group, the remaining 90 fish were divided equally into 3 groups as follows: LPS (2 mg/kg, IP, LPS (2 mg/kg, IP + florfenicol (40 mg/kg, IM, and florfenicol (40 mg/kg, IM. Blood samples were obtained from the tail of the fish at 1.5, 3, 6, 10, and 24 hours. The levels of sTNF-α were determined by ELISA and biochemical markers were evaluated with an autoanalyzer. A significant increase was observed in the values of sTNF-α in the LPS and LPS + florfenicol groups (P<0.05. Significant increases were found in the kidney and liver damage determinants in the LPS and LPS + florfenicol groups (P<0.05. Irregular changes in the lipid metabolism parameters were observed in all the subgroups. In conclusion, florfenicol does not affect the increases of sTNF-α caused by LPS and does not prevent liver or kidney damage; at least, it can be said that florfenicol does not have any evident positive effects on the acute endotoxemia of fish.

  8. Does Habitat Restoration Increase Coexistence of Native Stream Fishes with Introduced Brown Trout: A Case Study on the Middle Provo River, Utah, USA

    Directory of Open Access Journals (Sweden)

    Mark C. Belk

    2016-03-01

    Full Text Available Restoration of altered or degraded habitats is often a key component in the conservation plan of native aquatic species, but introduced species may influence the response of the native community to restoration. Recent habitat restoration of the middle section of the Provo River in central Utah, USA, provided an opportunity to evaluate the effect of habitat restoration on the native fish community in a system with an introduced, dominant predator—brown trout (Salmo trutta. To determine the change in distribution of fish species and community composition, we surveyed 200 m of each of the four study reaches both before restoration (1998 and after restoration (2007 and 2009. Juveniles and adults of six native species increased in distribution after restoration. The variation in fish community structure among reaches was lower post-restoration than pre-restoration. Overall, restoration of complex habitat in the middle Provo River led to increased pattern of coexistence between native fishes and introduced brown trout, but restoration activities did not improve the status of the river’s two rarest native fish species. Habitat restoration may only be completely successful in terms of restoring native communities when the abundance of invasive species can be kept at low levels.

  9. Impact of wastewater on fish health: a case study at the Neckar River (Southern Germany) using biomarkers in caged brown trout as assessment tools.

    Science.gov (United States)

    Vincze, Krisztina; Scheil, Volker; Kuch, Bertram; Köhler, Heinz R; Triebskorn, Rita

    2015-08-01

    The present work describes a field survey aiming at assessing the impact of a sewage treatment plant (STP) effluent on fish health by means of biomarkers. Indigenous fish were absent downstream of the STP. To elucidate the reason behind this, brown trout (Salmo trutta f. fario) were exposed in floating steel cages up- and downstream of a STP located at the Neckar River near Tübingen (Southern Germany), for 10 and 30 days. A combination of biomarker methods (histopathological investigations, analysis of the stress protein Hsp70, micronucleus test, B-esterase assays) offered the possibility to investigate endocrine, geno-, proteo- and neurotoxic effects in fish organs. Biological results were complemented with chemical analyses on 20 accumulative substances in fish tissue. Even after short-term exposure, biomarkers revealed clear evidence of water contamination at both Neckar River sites; however, physiological responses of caged brown trout were more severe downstream of the STP. According to this, similar bioaccumulation levels (low μg/kg range) of DDE and 12 polycyclic aromatic hydrocarbons (PAHs) were detected at both sampling sites, while up to fourfold higher concentrations of four PAHs, methyl-triclosan and two synthetic musks occurred in the tissues of downstream-exposed fish. The results obtained in this study suggest a constitutive background pollution at both sites investigated at the Neckar River and provided evidence for the additional negative impact of the STP Tübingen on water quality and the health condition of fish. PMID:25860546

  10. Acyl-coenzyme A oxidases 1 and 3 in brown trout (Salmo trutta f. fario): Can peroxisomal fatty acid β-oxidation be regulated by estrogen signaling?

    Science.gov (United States)

    Madureira, Tânia Vieira; Castro, L Filipe C; Rocha, Eduardo

    2016-02-01

    Acyl-coenzyme A oxidases 1 (Acox1) and 3 (Acox3) are key enzymes in the regulation of lipid homeostasis. Endogenous and exogenous factors can disrupt their normal expression/activity. This study presents for the first time the isolation and characterization of Acox1 and Acox3 in brown trout (Salmo trutta f. fario). Additionally, as previous data point to the existence of a cross-talk between two nuclear receptors, namely peroxisome proliferator-activated receptors and estrogen receptors, it was here evaluated after in vitro exposures of trout hepatocytes the interference caused by ethynylestradiol in the mRNA levels of an inducible (by peroxisome proliferators) and a non-inducible oxidase. The isolated Acox1 and Acox3 show high levels of sequence conservation compared to those of other teleosts. Additionally, it was found that Acox1 has two alternative splicing isoforms, corresponding to 3I and 3II isoforms of exon 3 splicing variants. Both isoforms display tissue specificity, with Acox1-3II presenting a more ubiquitous expression in comparison with Acox1-3I. Acox3 was expressed in almost all brown trout tissues. According to real-time PCR data, the highest estrogenic stimulus was able to cause a down-regulation of Acox1 and an up-regulation of Acox3. So, for Acox1 we found a negative association between an estrogenic input and a directly activated PPARα target gene. In conclusion, changes in hormonal estrogenic stimulus may impact the mobilization of hepatic lipids to the gonads, with ultimate consequences in reproduction. Further studies using in vivo assays will be fundamental to clarify these issues. PMID:26508171

  11. Population biology of coral trout species in eastern Torres Strait: Implications for fishery management

    Science.gov (United States)

    Williams, Ashley J.; Currey, Leanne M.; Begg, Gavin A.; Murchie, Cameron D.; Ballagh, Aaron C.

    2008-09-01

    Coral trout ( Plectropomus spp.) are the main target species for commercial fishers in the eastern Torres Strait Reef Line Fishery (ETS RLF). The four species of coral trout known to occur in Torres Strait: Plectropomus leopardus, Plectropomus maculatus, Plectropomus areolatus and Plectropomus laevis are currently managed as a single species in Torres Strait, as there is no species-specific biological information available for the region which could be used to assess whether species differ in their response to fishing pressure. The aim of our study was to determine whether it is appropriate (biologically) to manage coral trout in the ETS RLF as a single species group or whether different management arrangements are required for some species. We used catch data and biological data from samples collected by commercial fishers to examine the distribution within Torres Strait and estimate a range of biological parameters for P. leopardus, P. maculatus and P. areolatus. Insufficient P. laevis samples were collected to reliably examine this species. Results indicated that the population biology, particularly the reproductive biology, of P. areolatus was substantially different to both P. leopardus and P. maculatus. Although it is difficult to predict the response to fishing, P. areolatus may be more vulnerable to fishing than P. leopardus and P. maculatus, due to the larger size at sex change observed for this species and the very low proportion of males protected by the current minimum size limit. Therefore, while the common management arrangements for P. leopardus and P. maculatus appear to be adequate for these species, separate management arrangements are needed for the sustainable harvest of P. areolatus populations in the ETS. Specifically, we recommend the introduction of a maximum size limit for P. areolatus, in addition to the current minimum size limit, which may allow a proportion of males some protection from fishing.

  12. Dynamics of Na+,K+,2Cl- cotransporter and Na+,K+-ATPase expression in the branchial epithelium of brown trout (Salmo trutta) and Atlantic salmon (Salmo salar)

    DEFF Research Database (Denmark)

    Tipsmark, Christian Kølbæk; Madsen, Steffen; Seidelin, Michel;

    2002-01-01

    The dynamics of branchial Na+,K+,2Cl- cotransporter (NKCC) and Na+,K+-ATPase (NKA) expression were investigated in brown trout and Atlantic salmon during salinity shifts and the parr-smolt transformation, respectively. In the brown trout, Western blotting revealed that NKCC and NKA abundance...... SW-acclimated trout was strong, and mainly localized in large cells in the filament and around the bases of the lamellae. In FW-acclimated trout, immunostaining was less intense and more diffuse. Partial cDNAs of the secretory NKCC1 isoform were cloned and sequenced from both brown trout and Atlantic...... salmon gills. Two differently sized transcripts were detected by Northern blotting in the gill but not in other osmoregulatory tissues (kidney, pyloric caeca, intestine). The abundance in the gill of these transcripts and of the associated NKCC protein increased four- and 30-fold, respectively, during...

  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. Molecular identification of a bronopol tolerant strain of Saprolegnia australis causing egg and fry mortality in farmed brown trout, Salmo trutta.

    Science.gov (United States)

    Rezinciuc, Svetlana; Sandoval-Sierra, Jose-Vladimir; Diéguez-Uribeondo, Javier

    2014-07-01

    Some species of the genus Saprolegnia, such as Saprolegnia diclina and Saprolegnia ferax are responsible for devastating infections on salmonid eggs. Members of this group cause saprolegniasis, a disease resulting in considerable economic losses in aquaculture. Although both S. diclina and S. ferax have received much attention, the role of other Saprolegnia species in infecting fish eggs is less known. For this purpose, we have investigated the aetiology of chronic egg mortality events occurring in farmed brown trout, Salmo trutta. A total of 48 isolates were obtained from eggs with signs of infection as well as from water samples. A molecular analysis based on nrDNA internal transcribed spacer (ITS) operational taxonomic units indicated that the majority of the isolates correspond to Saprolegnia australis. All isolates of S. australis exhibited the same random amplified polymorphic DNA (RAPD) band patterns suggesting that a single strain is implicated in egg infections. The isolates followed Koch postulates using trout eggs and fry. Under standard concentrations of bronopol commonly used in farms, these isolates could grow, but not sporulate. However, both growth and sporulation were recovered when treatment was removed. This study shows that S. australis can infect and kill salmon eggs, and helps in defining oomycetes core pathogens. PMID:25088073

  15. Viral and bacterial septicaemic infections modulate the expression of PACAP splicing variants and VIP/PACAP receptors in brown trout immune organs.

    Science.gov (United States)

    Gorgoglione, Bartolomeo; Carpio, Yamila; Secombes, Christopher J; Taylor, Nick G H; Lugo, Juana María; Estrada, Mario Pablo

    2015-12-01

    Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) and PACAP-Related Peptide (PRP) are structurally similar peptides encoded in the same transcripts. Their transcription has been detected not only in the brain but also in a wide range of peripheral tissues, even including organs of the immune system. PACAP exerts pleiotropic activities through G-protein coupled membrane receptors: the PACAP-specific PAC-1 and the VPAC-1 and VPAC-2 receptors that exhibit similar affinities for the Vasoactive Intestinal Peptide (VIP) and PACAP. Recent findings added PACAP and its receptors to the growing list of mediators that allow cross-talk between the nervous, endocrine and immune systems in fish. In this study the expression of genes encoding for PACAP and PRP, as well as VIP/PACAP receptors was studied in laboratory-reared brown trout (Salmo trutta) after septicaemic infections. Respectively Viral Haemorrhagic Septicaemia Virus (VHSV-Ia) or the Gram-negative bacterium Yersinia ruckeri (ser. O1 - biot. 2) were used in infection challenges. Kidney and spleen, the teleost main lymphopoietic organs, were sampled during the first two weeks post-infection. RT-qPCR analysis assessed specific pathogens burden and gene expression levels. PACAP and PRP transcription in each organ was positively correlated to the respective pathogen burden, assessed targeting the VHSV-glycoprotein or Y. ruckeri 16S rRNA. Results showed as the transcription of PACAP splicing variants and VIP/PACAP receptors is modulated in these organs during an acute viral and bacterial septicaemic infections in brown trout. These gene expression results provide clues as to how the PACAP system is modulated in fish, confirming an involvement during active immune responses elicited by both viral and bacterial aetiological agents. However, further experimental evidence is still required to fully elucidate and characterize the role of PACAP and PRP for an efficient immune response against pathogens. PMID:26481517

  16. Ascent ability of brown trout, Salmo trutta, and two Iberian cyprinids − Iberian barbel, Luciobarbus bocagei, and northern straight-mouth nase, Pseudochondrostoma duriense − in a vertical slot fishway

    Science.gov (United States)

    Sanz-Ronda, Fco. Javier; Bravo-Cordoba, F.J.; Fuentes-Perez, J.F.; Castro-Santos, Theodore R.

    2016-01-01

    Passage performance of brown trout (Salmo trutta), Iberian barbel (Luciobarbus bocagei), and northern straight-mouth nase (Pseudochondrostoma duriense) was investigated in a vertical slot fishway in the Porma River (Duero River basin, Spain) using PIT telemetry. We analysed the effects of different fishway discharges on motivation and passage success. Both cyprinid species ascended the fishway easily, performing better than the trout despite their theoretically weaker swimming performance. Fishway discharge affected fish motivation although it did not clearly influence passage success. Observed results can guide design and operation criteria of vertical slot fishways for native Iberian fish.

  17. An assessment of the spatial scale of local adaptation in brown trout (Salmo trutta L.): footprints of selection at microsatellite DNA loci

    DEFF Research Database (Denmark)

    Meier, Kristian; Hansen, Michael Møller; Bekkevold, Dorte;

    2011-01-01

    to spawning intrusion by farmed conspecifics that experience selection regimes fundamentally different from wild populations. This prompts the question if adaptive differences between wild populations and hatchery strains are more pronounced than between different wild populations? We addressed these issues...... of outliers between regions was evident. There was no evidence for more outliers in comparisons involving hatchery trout, but the loci under putative selection generally were not the same as those found to be outliers between wild populations. Our study supports the notion of local adaption being increasingly......Local adaptation is considered a paradigm in studies of salmonid fish populations. Yet, little is known about the geographical scale of local adaptation. Is adaptive divergence primarily evident at the scale of regions or individual populations? Also, many salmonid populations are subject...

  18. Effects on the trout and the evertebrate population in the stream Vulluelva during the first year following mass mortality by oil spill; Effekter paa oerret og bunndyr i Vulluelva foerste aaret etter et massivt oljeutslipp

    Energy Technology Data Exchange (ETDEWEB)

    Lund, R.A.; Noest, T.; Finstad, B.

    1996-12-31

    Following the crash of a tanker truck in the autumn of 1994, 27000 litres of petrol, paraffin and diesel oil accidentally spilt into the river Vulluelva, Norway. This report discusses the observed biological effects of the spill. The spill immediately killed the entire brown trout parr population in the lower half of the stream and 30% of the sea trout spawning population. A few weeks later, after extensive clean-up and of heavy flood, significant numbers of trout spawned within a limited river stretch in the lowest part of the stream and not in the normally more favoured spawning habitats further upstream. Analyses of the chloride content of blood plasma of parr and spawners sampled at the final phase of the spawning period showed only a few cases of stressed physiological condition. The significant variation in the observed egg survival in the river stretch preferred for spawning may be related to possible negative impacts by hydrocarbons. The study demonstrates no negative impacts on fry growth during the first season following the contamination. Mass mortality of the zoobenthos followed the oil spill in October 1994 and the populations of the dominating groups were reduced to a very low level. The recovery of zoobenthos was not complete until 9-10 months later. 62 refs., 8 figs., 11 tabs.

  19. Species interactions and response time to climate change: ice-cover and terrestrial run-off shaping Arctic char and brown trout competitive asymmetries

    Science.gov (United States)

    Finstad, A. G.; Palm Helland, I.; Jonsson, B.; Forseth, T.; Foldvik, A.; Hessen, D. O.; Hendrichsen, D. K.; Berg, O. K.; Ulvan, E.; Ugedal, O.

    2011-12-01

    There has been a growing recognition that single species responses to climate change often mainly are driven by interaction with other organisms and single species studies therefore not are sufficient to recognize and project ecological climate change impacts. Here, we study how performance, relative abundance and the distribution of two common Arctic and sub-Arctic freshwater fishes (brown trout and Arctic char) are driven by competitive interactions. The interactions are modified both by direct climatic effects on temperature and ice-cover, and indirectly through climate forcing of terrestrial vegetation pattern and associated carbon and nutrient run-off. We first use laboratory studies to show that Arctic char, which is the world's most northernmost distributed freshwater fish, outperform trout under low light levels and also have comparable higher growth efficiency. Corresponding to this, a combination of time series and time-for-space analyses show that ice-cover duration and carbon and nutrient load mediated by catchment vegetation properties strongly affected the outcome of the competition and likely drive the species distribution pattern through competitive exclusion. In brief, while shorter ice-cover period and decreased carbon load favored brown trout, increased ice-cover period and increased carbon load favored Arctic char. Length of ice-covered period and export of allochthonous material from catchments are major, but contrasting, climatic drivers of competitive interaction between these two freshwater lake top-predators. While projected climate change lead to decreased ice-cover, corresponding increase in forest and shrub cover amplify carbon and nutrient run-off. Although a likely outcome of future Arctic and sub-arctic climate scenarios are retractions of the Arctic char distribution area caused by competitive exclusion, the main drivers will act on different time scales. While ice-cover will change instantaneously with increasing temperature

  20. Survival of Trout Strains as Affected by Limnological Parameters

    OpenAIRE

    Wurtsbaugh, Wayne A.

    1988-01-01

    Prior work at East Canyon Reservoir, Utah indicated that adult trout are important predators of stocked juvenile rainbow trout. Brown trout, in particular, were exclusively piscivorous when th~y exceeded 185 mm standard length. Fish became increasingly important in the diet of cutthroat trout greater than 330 mm. The purpose of this study was to further document the effect of adult trout on survival of juvenile rainbow trout in mid-elevation reservoirs. Causey Reservoir was chosen because it ...

  1. Variability of kokanee and rainbow trout food habits, distribution, and population dynamics, in an ultraoligotrophic lake with no manipulative management

    Science.gov (United States)

    Buktenica, M.W.; Girdner, S.F.; Larson, G.L.; McIntire, C.D.

    2007-01-01

    Crater Lake is a unique environment to evaluate the ecology of introduced kokanee and rainbow trout because of its otherwise pristine state, low productivity, absence of manipulative management, and lack of lotic systems for fish spawning. Between 1986 and 2004, kokanee displayed a great deal of variation in population demographics with a pattern that reoccurred in about 10 years. We believe that the reoccurring pattern resulted from density dependent growth, and associated changes in reproduction and abundance, driven by prey resource limitation that resulted from low lake productivity exacerbated by prey consumption when kokanee were abundant. Kokanee fed primarily on small-bodied prey from the mid-water column; whereas rainbow trout fed on large-bodied prey from the benthos and lake surface. Cladoceran zooplankton abundance may be regulated by kokanee. And kokanee growth and reproductive success may be influenced by the availability of Daphnia pulicaria, which was absent in zooplankton samples collected annually from 1990 to 1995, and after 1999. Distribution and diel migration of kokanee varied over the duration of the study and appeared to be most closely associated with prey availability, maximization of bioenergetic efficiency, and fish density. Rainbow trout were less abundant than were kokanee and exhibited less variation in population demographics, distribution, and food habits. There is some evidence that the population dynamics of rainbow trout were in-part related to the availability of kokanee as prey. ?? 2007 Springer Science+Business Media B.V.

  2. Genetic and Phenotypic Catalog of Native Resident Trout of the interior Columbia River Basin : FY-2001 Report : Populations in the Wenatchee, Entiat, Lake Chelan and Methow River Drainages.

    Energy Technology Data Exchange (ETDEWEB)

    Trotter, Patrick C.

    2001-10-01

    The 1994 Fish and Wildlife Program of the Northwest Power Planning Council specifies the recovery and preservation of population health of native resident fishes of the Columbia River Basin. Among the native resident species of concern are interior rainbow trout of the Columbia River redband subspecies Oncorhynchus mykiss gairdneri 1 and westslope cutthroat trout O. clarki lewisi. The westslope cutthroat trout has been petitioned for listing under the U. S. Endangered Species Act (American Wildlands et al. 1997). Before at-risk populations can be protected, their presence and status must be established. Where introgression from introduced species is a concern, as in the case of both westslope cutthroat trout and redband rainbow trout, genetic issues must be addressed as well. As is true with native trout elsewhere in the western United States (Behnke 1992), most of the remaining pure populations of these species in the Columbia River Basin are in relatively remote headwater reaches. The objective of this project was to photo-document upper Columbia Basin native resident trout populations in Washington, and to ascertain their species or subspecies identity and relative genetic purity using a nonlethal DNA technique. FY-2001 was year three (and final year) of a project in which we conducted field visits to remote locations to seek out and catalog these populations. In FY-2001 we worked in collaboration with the Wenatchee National Forest to catalog populations in the Wenatchee, Entiat, Lake Chelan, and Methow River drainages of Washington State.

  3. Microlensing Discovery of a Population of Very Tight, Very Low-mass Binary Brown Dwarfs

    CERN Document Server

    Choi, J -Y; Udalski, A; Sumi, T; Gaudi, B S; Gould, A; Bennett, D P; Dominik, M; Beaulieu, J -P; Tsapras, Y; Bozza, V; Abe, F; Bond, I A; Botzler, C S; Chote, P; Freeman, M; Fukui, A; Furusawa, K; Itow, Y; Ling, C H; Masuda, K; Matsubara, Y; Miyake, N; Muraki, Y; Ohnishi, K; Rattenbury, N J; Saito, To; Sullivan, D J; Suzuki, K; Sweatman, W L; Suzuki, D; Takino, S; Tristram, P J; Wada, K; Yock, P C M; Szymański, M K; Kubiak, M; Pietrzyński, G; Soszyński, I; Skowron, J; Kozłowski, S; Poleski, R; Ulaczyk, K; Wyrzykowski, Ł; Pietrukowicz, P; Almeida, L A; DePoy, D L; Dong, Subo; Gorbikov, E; Jablonski, F; Henderson, C B; Hwang, K -H; Janczak, J; Jung, Y -K; Kaspi, S; Lee, C -U; Malamud, U; Maoz, D; McGregor, D; Munoz, J A; Park, B -G; Park, H; Pogge, R W; Shvartzvald, Y; Shin, I -G; Yee, J C; Alsubai, K A; Browne, P; Burgdorf, M J; Novati, S Calchi; Dodds, P; Fang, X -S; Finet, F; Glitrup, M; Grundahl, F; Gu, S -H; Hardis, S; Harpsøe, K; Hinse, T C; Hornstrup, A; Hundertmark, M; Jessen-Hansen, J; Jørgensen, U G; Kains, N; Kerins, E; Liebig, C; Lund, M N; Lundkvist, M; Maier, G; Mancini, L; Mathiasen, M; Penny, M T; Rahvar, S; Ricci, D; Scarpetta, G; Skottfelt, J; Snodgrass, C; Southworth, J; Surdej, J; Tregloan-Reed, J; Wambsganss, J; Wertz, O; Zimmer, F; Albrow, M D; Bachelet, E; Batista, V; Brillant, S; Cassan, A; Cole, A A; Coutures, C; Dieters, S; Prester, D Dominis; Donatowicz, J; Fouqué, P; Greenhill, J; Kubas, D; Marquette, J -B; Menzies, J W; Sahu, K C; Zub, M; Bramich, D M; Horne, K; Steele, I A; Street, R A

    2013-01-01

    Although many models have been proposed, the physical mechanisms responsible for the formation of low-mass brown dwarfs are poorly understood. The multiplicity properties and minimum mass of the brown-dwarf mass function provide critical empirical diagnostics of these mechanisms. We present the discovery via gravitational microlensing of two very low-mass, very tight binary systems. These binaries have directly and precisely measured total system masses of 0.025 Msun and 0.034 Msun, and projected separations of 0.31 AU and 0.19 AU, making them the lowest-mass and tightest field brown-dwarf binaries known. The discovery of a population of such binaries indicates that brown dwarf binaries can robustly form at least down to masses of ~0.02 Msun. Future microlensing surveys will measure a mass-selected sample of brown-dwarf binary systems, which can then be directly compared to similar samples of stellar binaries.

  4. The effect of recurrent floods on genetic composition of marble trout populations.

    Directory of Open Access Journals (Sweden)

    José Martin Pujolar

    Full Text Available A changing global climate can threaten the diversity of species and ecosystems. We explore the consequences of catastrophic disturbances in determining the evolutionary and demographic histories of secluded marble trout populations in Slovenian streams subjected to weather extremes, in particular recurrent flash floods and debris flows causing massive mortalities. Using microsatellite data, a pattern of extreme genetic differentiation was found among populations (global F(ST of 0.716, which exceeds the highest values reported in freshwater fish. All locations showed low levels of genetic diversity as evidenced by low heterozygosities and a mean of only 2 alleles per locus, with few or no rare alleles. Many loci showed a discontinuous allele distribution, with missing alleles across the allele size range, suggestive of a population contraction. Accordingly, bottleneck episodes were inferred for all samples with a reduction in population size of 3-4 orders of magnitude. The reduced level of genetic diversity observed in all populations implies a strong impact of genetic drift, and suggests that along with limited gene flow, genetic differentiation might have been exacerbated by recurrent mortalities likely caused by flash flood and debris flows. Due to its low evolutionary potential the species might fail to cope with an intensification and altered frequency of flash flood events predicted to occur with climate change.

  5. 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

  6. Genetic diversity and differentiation of sea trout (Salmo trutta) populations in Lithuanian rivers assessed by microsatellite DNA variation.

    Science.gov (United States)

    Samuiloviene, Aurelija; Kontautas, Antanas; Gross, Riho

    2009-11-01

    The genetic diversity and differentiation of sea trout were studied in three river basins in Lithuania: Akmena-Dane, Bartuva, and Nemunas. A total of 282 individuals were genotyped at eight microsatellite loci. A similar level of genetic diversity was found in all of the populations studied: mean allelic richness ranged from 3.64 to 5.03, and average expected heterozygosity ranged from 0.588 to 0.721. Significant genetic divergence was observed among the different river basins as well as between populations within the drainages. All pairwise F (ST) values were highly significant, ranging from 0.027 to 0.197. The analysis of molecular variance showed rather weak hierarchical population structuring within the Nemunas basin, which may be explained by extensive gene flow among different river basins or, alternatively, reflect the influence of artificial breeding. Information on genetic diversity and differentiation of the Lithuanian sea trout populations will be useful for future management decisions.

  7. Dietary peppermint (Mentha piperita) extracts promote growth performance and increase the main humoral immune parameters (both at mucosal and systemic level) of Caspian brown trout (Salmo trutta caspius Kessler, 1877).

    Science.gov (United States)

    Adel, Milad; Safari, Reza; Pourgholam, Reza; Zorriehzahra, Jalil; Esteban, Maria Ángeles

    2015-11-01

    The effects of dietary administration of peppermint (Mentha piperita L.) on Caspian brown trout fish (Salmo trutta caspius) were studied. Fish were divided into 4 groups before being fed diets supplemented with 0% (control), 1%, 2% and 3% of peppermint extracts for 8 weeks. Dose-dependent increases in growth, immune (both in skin mucus and blood serum) and hematological parameters (number of white cells, hematocrit and hemoglobin content), as well as in amylase activity and in the number of lactic acid bacteria on intestine were recorded in fish fed supplemented diets compared to control fish. However, the dietary peppermint supplements have different effects on the number of blood leucocytes depending on the leukocyte cell type. While no significant differences were observed in the number of blood monocytes and eosinophils, the number of lymphocytes was decreased, respectively, on fish fed peppermint enriched diets, respect to the values found in control fish. Furthermore, dietary peppermint supplements have no significant effect on blood biochemical parameters, enzymatic activities of liver determined in serum and total viable aerobic bacterial count on intestine of Caspian brown trout. Present results support that dietary administration of peppermint promotes growth performance and increases the main humoral immune parameters (both at mucosal and systemic level) and the number of the endogenous lactic acid bacteria of Caspian brown trout. This study underlying several positive effects of dietary administration of peppermint to farmed fish.

  8. Dietary peppermint (Mentha piperita) extracts promote growth performance and increase the main humoral immune parameters (both at mucosal and systemic level) of Caspian brown trout (Salmo trutta caspius Kessler, 1877).

    Science.gov (United States)

    Adel, Milad; Safari, Reza; Pourgholam, Reza; Zorriehzahra, Jalil; Esteban, Maria Ángeles

    2015-11-01

    The effects of dietary administration of peppermint (Mentha piperita L.) on Caspian brown trout fish (Salmo trutta caspius) were studied. Fish were divided into 4 groups before being fed diets supplemented with 0% (control), 1%, 2% and 3% of peppermint extracts for 8 weeks. Dose-dependent increases in growth, immune (both in skin mucus and blood serum) and hematological parameters (number of white cells, hematocrit and hemoglobin content), as well as in amylase activity and in the number of lactic acid bacteria on intestine were recorded in fish fed supplemented diets compared to control fish. However, the dietary peppermint supplements have different effects on the number of blood leucocytes depending on the leukocyte cell type. While no significant differences were observed in the number of blood monocytes and eosinophils, the number of lymphocytes was decreased, respectively, on fish fed peppermint enriched diets, respect to the values found in control fish. Furthermore, dietary peppermint supplements have no significant effect on blood biochemical parameters, enzymatic activities of liver determined in serum and total viable aerobic bacterial count on intestine of Caspian brown trout. Present results support that dietary administration of peppermint promotes growth performance and increases the main humoral immune parameters (both at mucosal and systemic level) and the number of the endogenous lactic acid bacteria of Caspian brown trout. This study underlying several positive effects of dietary administration of peppermint to farmed fish. PMID:26455650

  9. Factors driving spatial and temporal variation in production and production/biomass ratio of stream-resident brown trout (Salmo trutta) in Cantabrian streams

    Science.gov (United States)

    Lobon-Cervia, J.; Gonzalez, G.; Budy, P.

    2011-01-01

    1.The objective was to identify the factors driving spatial and temporal variation in annual production (PA) and turnover (production/biomass) ratio (P/BA) of resident brown trout Salmo trutta in tributaries of the Rio Esva (Cantabrian Mountains, Asturias, north-western Spain). We examined annual production (total production of all age-classes over a year) (PA) and turnover (P/BA) ratios, in relation to year-class production (production over the entire life time of a year-class) (PT) and turnover (P/BT) ratio, over 14years at a total of 12 sites along the length of four contrasting tributaries. In addition, we explored whether the importance of recruitment and site depth for spatial and temporal variations in year-class production (PT), elucidated in previous studies, extends to annual production. 2.Large spatial (among sites) and temporal (among years) variation in annual production (range 1.9-40.3gm-2 per year) and P/BA ratio (range 0.76-2.4per year) typified these populations, values reported here including all the variation reported globally for salmonids streams inhabited by one or several species. 3.Despite substantial differences among streams and sites in all production attributes, when all data were pooled, annual (PA) and year-class production (PT) and annual (P/BA) and year-class P/BT ratios were tightly linked. Annual (PA) and year-class production (PT) were similar but not identical, i.e. PT=0.94 PA, whereas the P/BT ratios were 4+P/BA ratios. 4.Recruitment (Rc) and mean annual density (NA) were major density-dependent drivers of production and their relationships were described by simple mathematical models. While year-class production (PT) was determined (R2=70.1%) by recruitment (Rc), annual production (PA) was determined (R2=60.3%) by mean annual density (NA). In turn, variation in recruitment explained R2=55.2% of variation in year-class P/BT ratios, the latter attaining an asymptote at P/BT=6 at progressively higher levels of recruitment

  10. Interactions Between Trout and Sculpin: Consequences of Trout Introductions for a Native Fish

    Science.gov (United States)

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

    2005-05-01

    We examined interactions between a native (brook) and a nonnative (brown) trout with native slimy sculpin, to test whether introductions of a nonnative salmonid has an effect on growth and diet of sculpin where a native trout was present. Enclosures (1m2) were stocked with fish (five treatments: juvenile brown trout with sculpin, juvenile brook trout with sculpin, and single species controls) at three densities. Replicates of each treatment were placed in Valley Creek, MN, and fish growth rates were measured over six 38-day experiments, conducted over three years. We examined growth of each species in combined-species treatments versus growth of each species alone. We did not find evidence of competition between brook trout and sculpin, regardless of density or fish size. However, we observed competition between brown trout and sculpin, which depended on initial mass of each species. Sculpin gained greater mass when alone than with brown trout when sculpin size was large (>17g). Likewise, brown trout gained greater mass alone than with sculpin when brown trout size was large (>26g). We suggest that differences in morphology and foraging modes between the two native species allow them to coexist without competition, whereas nonnative brown trout compete with sculpin.

  11. Estrogenic and anti-estrogenic influences in cultured brown trout hepatocytes: Focus on the expression of some estrogen and peroxisomal related genes and linked phenotypic anchors.

    Science.gov (United States)

    Madureira, Tânia Vieira; Malhão, Fernanda; Pinheiro, Ivone; Lopes, Célia; Ferreira, Nádia; Urbatzka, Ralph; Castro, L Filipe C; Rocha, Eduardo

    2015-12-01

    Estrogens, estrogenic mimics and anti-estrogenic compounds are known to target estrogen receptors (ER) that can modulate other nuclear receptor signaling pathways, such as those controlled by the peroxisome proliferator-activated receptor (PPAR), and alter organelle (inc. peroxisome) morphodynamics. By using primary isolated brown trout (Salmo trutta f. fario) hepatocytes after 72 and 96h of exposure we evaluated some effects in selected molecular targets and in peroxisomal morphological features caused by: (1) an ER agonist (ethinylestradiol-EE2) at 1, 10 and 50μM; (2) an ER antagonist (ICI 182,780) at 10 and 50μM; and (3) mixtures of both (Mix I-10μM EE2 and 50μM ICI; Mix II-1μM EE2 and 10μM ICI and Mix III-1μM EE2 and 50μM ICI). The mRNA levels of the estrogenic targets (ERα, ERβ-1 and vitellogenin A-VtgA) and the peroxisome structure/function related genes (catalase, urate oxidase-Uox, 17β-hydroxysteroid dehydrogenase 4-17β-HSD4, peroxin 11α-Pex11α and PPARα) were analyzed by real-time polymerase chain reaction (RT-PCR). Stereology combined with catalase immunofluorescence revealed a significant reduction in peroxisome volume densities at 50μM of EE2 exposure. Concomitantly, at the same concentration, electron microscopy showed smaller peroxisome profiles, exacerbated proliferation of rough endoplasmic reticulum, and a generalized cytoplasmic vacuolization of hepatocytes. Catalase and Uox mRNA levels decreased in all estrogenic stimuli conditions. VtgA and ERα mRNA increased after all EE2 treatments, while ERβ-1 had an inverse pattern. The EE2 action was reversed by ICI 182,780 in a concentration-dependent manner, for VtgA, ERα and Uox. Overall, our data show the great value of primary brown trout hepatocytes to study the effects of estrogenic/anti-estrogenic inputs in peroxisome kinetics and in ER and PPARα signaling, backing the still open hypothesis of crosstalk interactions between these pathways and calling for more mechanistic

  12. Analysis of regional scale risk to whirling disease in populations of Colorado and Rio Grande cutthroat trout using Bayesian belief network model

    Science.gov (United States)

    Kolb Ayre, Kimberley; Caldwell, Colleen A.; Stinson, Jonah; Landis, Wayne G.

    2014-01-01

    Introduction and spread of the parasite Myxobolus cerebralis, the causative agent of whirling disease, has contributed to the collapse of wild trout populations throughout the intermountain west. Of concern is the risk the disease may have on conservation and recovery of native cutthroat trout. We employed a Bayesian belief network to assess probability of whirling disease in Colorado River and Rio Grande cutthroat trout (Oncorhynchus clarkii pleuriticus and Oncorhynchus clarkii virginalis, respectively) within their current ranges in the southwest United States. Available habitat (as defined by gradient and elevation) for intermediate oligochaete worm host, Tubifex tubifex, exerted the greatest influence on the likelihood of infection, yet prevalence of stream barriers also affected the risk outcome. Management areas that had the highest likelihood of infected Colorado River cutthroat trout were in the eastern portion of their range, although the probability of infection was highest for populations in the southern, San Juan subbasin. Rio Grande cutthroat trout had a relatively low likelihood of infection, with populations in the southernmost Pecos management area predicted to be at greatest risk. The Bayesian risk assessment model predicted the likelihood of whirling disease infection from its principal transmission vector, fish movement, and suggested that barriers may be effective in reducing risk of exposure to native trout populations. Data gaps, especially with regard to location of spawning, highlighted the importance in developing monitoring plans that support future risk assessments and adaptive management for subspecies of cutthroat trout.

  13. Genetic and Phenotypic Catalog of Native Resident Trout of the Interior Columbia River Basin; Populations of the Upper Yakima Basin, 1997-1998 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Trotter, Patrick C. (Fishery Science Consultant, Seattle, WA); McMillan, Bill; Gayeski, Nick (Washington Trout, Duvall, WA)

    1999-10-01

    The objective of this project is to photo-document upper Columbia Basin native resident trout populations in Washington, and to ascertain their species or subspecies identity and relative genetic purity using a nonlethal DNA technique.

  14. Density-dependent regulation of brook trout population dynamics along a core-periphery distribution gradient in a central Appalachian watershed.

    Directory of Open Access Journals (Sweden)

    Brock M Huntsman

    Full Text Available Spatial population models predict strong density-dependence and relatively stable population dynamics near the core of a species' distribution with increasing variance and importance of density-independent processes operating towards the population periphery. Using a 10-year data set and an information-theoretic approach, we tested a series of candidate models considering density-dependent and density-independent controls on brook trout population dynamics across a core-periphery distribution gradient within a central Appalachian watershed. We sampled seven sub-populations with study sites ranging in drainage area from 1.3-60 km(2 and long-term average densities ranging from 0.335-0.006 trout/m. Modeled response variables included per capita population growth rate of young-of-the-year, adult, and total brook trout. We also quantified a stock-recruitment relationship for the headwater population and coefficients of variability in mean trout density for all sub-populations over time. Density-dependent regulation was prevalent throughout the study area regardless of stream size. However, density-independent temperature models carried substantial weight and likely reflect the effect of year-to-year variability in water temperature on trout dispersal between cold tributaries and warm main stems. Estimated adult carrying capacities decreased exponentially with increasing stream size from 0.24 trout/m in headwaters to 0.005 trout/m in the main stem. Finally, temporal variance in brook trout population size was lowest in the high-density headwater population, tended to peak in mid-sized streams and declined slightly in the largest streams with the lowest densities. Our results provide support for the hypothesis that local density-dependent processes have a strong control on brook trout dynamics across the entire distribution gradient. However, the mechanisms of regulation likely shift from competition for limited food and space in headwater streams to

  15. Density-dependent regulation of brook trout population dynamics along a core-periphery distribution gradient in a central Appalachian watershed.

    Science.gov (United States)

    Huntsman, Brock M; Petty, J Todd

    2014-01-01

    Spatial population models predict strong density-dependence and relatively stable population dynamics near the core of a species' distribution with increasing variance and importance of density-independent processes operating towards the population periphery. Using a 10-year data set and an information-theoretic approach, we tested a series of candidate models considering density-dependent and density-independent controls on brook trout population dynamics across a core-periphery distribution gradient within a central Appalachian watershed. We sampled seven sub-populations with study sites ranging in drainage area from 1.3-60 km(2) and long-term average densities ranging from 0.335-0.006 trout/m. Modeled response variables included per capita population growth rate of young-of-the-year, adult, and total brook trout. We also quantified a stock-recruitment relationship for the headwater population and coefficients of variability in mean trout density for all sub-populations over time. Density-dependent regulation was prevalent throughout the study area regardless of stream size. However, density-independent temperature models carried substantial weight and likely reflect the effect of year-to-year variability in water temperature on trout dispersal between cold tributaries and warm main stems. Estimated adult carrying capacities decreased exponentially with increasing stream size from 0.24 trout/m in headwaters to 0.005 trout/m in the main stem. Finally, temporal variance in brook trout population size was lowest in the high-density headwater population, tended to peak in mid-sized streams and declined slightly in the largest streams with the lowest densities. Our results provide support for the hypothesis that local density-dependent processes have a strong control on brook trout dynamics across the entire distribution gradient. However, the mechanisms of regulation likely shift from competition for limited food and space in headwater streams to competition for

  16. Gene flow between insular, coastal and interior populations of brown bears in Alaska.

    Science.gov (United States)

    Paetkau, D; Shields, G F; Strobeck, C

    1998-10-01

    The brown bears of coastal Alaska have been recently regarded as comprising from one to three distinct genetic groups. We sampled brown bears from each of the regions for which hypotheses of genetic uniqueness have been made, including the bears of the Kodiak Archipelago and the bears of Admiralty, Baranof and Chichagof (ABC) Islands in southeast Alaska. These samples were analysed with a suite of nuclear microsatellite markers. The 'big brown bears' of coastal Alaska were found to be part of the continuous continental distribution of brown bears, and not genetically isolated from the physically smaller 'grizzly bears' of the interior. By contrast, Kodiak brown bears appear to have experienced little or no genetic exchange with continental populations in recent generations. The bears of the ABC Islands, which have previously been shown to undergo little or no female-mediated gene flow with mainland populations, were found not to be genetically isolated from mainland bears. The data from the four insular populations indicate that female and male dispersal can be reduced or eliminated by water barriers of 2-4 km and 7 km in width, respectively.

  17. 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

  18. GENETIC DIVERSITY AND POPULATION STRUCTURE OF WILD AND CULTIVATED BROWN SEA MUSTARD, UNDARIA PINNATIFIDA

    OpenAIRE

    Man, Kyu; Hong, Wook

    2002-01-01

    Enzyme electrophoresis was used to estimate genetic diversity and population structure of the wild and cultivated sea mustard, Undaria pinnatifida (Harvey) Suringar. Compared with other ecologically and economically significant brown seaweed, population structure of this species has not been studied. The objectives of this study were to estimate the levels of genetic diversity in the wild and cultivated populations and to describe the distribution of genetic variation within and among its pop...

  19. Population Structure of Columbia River Basin Chinook Salmon and Steelhead Trout, Technical Report 2001.

    Energy Technology Data Exchange (ETDEWEB)

    Brannon, E.L.; National Science Foundation (U.S.)

    2002-08-01

    The population structure of chinook salmon and steelhead trout is presented as an assimilation of the life history forms that have evolved in synchrony with diverse and complex environments over their Pacific range. As poikilotherms, temperature is described as the overwhelming environmental influence that determines what life history options occur and where they are distributed. The different populations represent ecological types referred to as spring-, summer-, fall, and winter-run segments, as well as stream- and ocean-type, or stream- and ocean-maturing life history forms. However, they are more correctly described as a continuum of forms that fall along a temporal cline related to incubation and rearing temperatures that determine spawn timing and juvenile residence patterns. Once new habitats are colonized, members of the founding populations spread through adaptive evolution to assume complementary life history strategies. The related population units are collectively referred to as a metapopulation, and members most closely associated within common temporal and geographic boundaries are designated as first-order metapopulations. Population structure of chinook salmon and steelhead in the Columbia Basin, therefore, is the reflection of the genetic composition of the founding source or sources within the respective region, shaped by the environment, principally temperature, that defines life history evolutionary strategy to maximize fitness under the conditions delineated. The complexity of structure rests with the diversity of opportunities over the elevations that exist within the Basin. Consistent with natural selection, rather than simply attempting to preserve populations, the challenge is to provide opportunities to expand their range to new or restored habitat that can accommodate genetic adaptation as directional environmental changes are elaborated. Artificial propagation can have a critical role in this process, and the emphasis must be placed on

  20. A legacy of divergent fishery management regimes and the resilience of rainbow and cutthroat trout populations in Lake Crescent, Olympic National Park, Washington

    Science.gov (United States)

    Brenkman, Samuel J.; Duda, Jeffrey J.; Kennedy, Philip R.; Baker, Bruce M.

    2014-01-01

    As a means to increase visitation, early fisheries management in the National Park Service (NPS) promoted sport harvest and hatchery supplementation. Today, NPS management objectives focus on the preservation of native fish. We summarized management regimes of Olympic National Park's Lake Crescent, which included decades of liberal sport harvest and hatchery releases of 14.3 million salmonids. Notably, nonnative species failed to persist in the lake. Complementary analyses of annual redd counts (1989–2012) and genetics data delineated three sympatric trout (one rainbow; two cutthroat) populations that exhibited distinct spatial and temporal spawning patterns, variable emergence timings, and genetic distinctiveness. Allacustrine rainbow trout spawned in the lake outlet from January to May. Cutthroat trout spawned in the major inlet tributary (Barnes Creek) from February to June and in the outlet river (Lyre) from September to March, an unusual timing for coastal cutthroat trout. Redd counts for each species were initially low (rainbow = mean 89; range 37–159; cutthroat = mean 93; range 18–180), and significantly increased for rainbow trout (mean 306; range 254–352) after implementation of catch-and-release regulations. Rainbow and cutthroat trout reached maximum sizes of 10.4 kg and 5.4 kg, respectively, and are among the largest throughout their native ranges. Morphometric analyses revealed interspecific differences but no intraspecific differences between the two cutthroat populations. Genetic analyses identified three distinct populations and low levels (9–17%) of interspecific hybridization. Lake Crescent rainbow trout were genetically divergent from 24 nearby Oncorhynchus mykiss populations, and represented a unique evolutionary legacy worthy of protection. The indigenous and geographically isolated Lake Crescent trout populations were resilient to overharvest and potential interactions with introduced fish species.

  1. Comparison of the macroparasite communities of stocked and wild trout (Salmo trutta) from the West of Ireland

    OpenAIRE

    HOLLAND, CELIA

    2002-01-01

    PUBLISHED The aim of the present study was to compare the helminth infra and component communities of wild and stocked brown trout in Lough Feeagh, in the west of Ireland, and also to examine the establishment and development of helminth communities in stocked brown trout. Fish were sampled in May, August and November 1997 and 1998 and an additional sample of wild brown trout was examined in April 1997. In total 217 wild trout and 122 stocked trout were examined. The acanthocephalans Acant...

  2. Evidence of source-sink metapopulations in a vulnerable native galaxiid fish driven by introduced trout.

    Science.gov (United States)

    Woodford, Darragh J; McIntosh, Angus R

    2010-06-01

    Introduced predators with patchy distributions can create demographic sinks within native prey populations. Such invasions may give rise to source-sink metapopulations if there are still sources of native species colonists in the landscape. In New Zealand, introduced brown trout (Salmo trutta) and rainbow trout (Oncorhychus mykiss) are linked with declines in native non-diadromous galaxiids but co-occur with these galaxiids in some locations. We investigated whether trout create sinks in Galaxias vulgaris populations, and whether trout-free reaches could act as sources, allowing persistence in the sink habitat. We conducted quantitative seasonal monitoring of G. vulgaris population structure across two subcatchments of the Waimakariri River, South Island. Two trout-free and seven trout-invaded sites in the Porter River catchment and two trout-free and five trout-invaded sites in the Broken River catchment were monitored over two winters and the adjoining summer. Spatially continuous monitoring of young-of-the-year (YOY) galaxiid distributions and apparent survival across the Broken River catchment was also undertaken. Galaxias vulgaris YOY recruitment was high in trout-free reaches, indicating positive population growth. Galaxias vulgaris was absent from three trout-invaded sites, and the remaining invaded sites had significantly depleted juvenile recruitment. Information-theoretic model selection indicated that trout, rather than habitat, drove recruitment failure. Trout-invaded sites could be divided into "sinks" that retained no YOY galaxiids, indicating no local recruitment, and "pseudosinks," which had very few recruits. Absence of small G. vulgaris at sink sites suggested population maintenance through immigration of adults from sources, whereas pseudosink sites appear capable of self-recruitment at low carrying capacities. Trout-free reaches appear to act as sources in a river network but are susceptible to future invasions by trout. Thus, not only may

  3. Assessment of brown trout habitat suitability in the Jucar River Basin (SPAIN): comparison of data-driven approaches with fuzzy-logic models and univariate suitability curves.

    Science.gov (United States)

    Muñoz-Mas, Rafael; Martínez-Capel, Francisco; Schneider, Matthias; Mouton, Ans M

    2012-12-01

    The implementation of the Water Framework Directive implies the determination of an environmental flow (E-flow) in each running water body. In Spain, many of the minimum flow assessments were determined with the physical habitat simulation system based on univariate habitat suitability curves. Multivariate habitat suitability models, widely applied in habitat assessment, are potentially more accurate than univariate suitability models. This article analyses the microhabitat selection by medium-sized (10-20 cm) brown trout (Salmo trutta fario) in three streams of the Jucar River Basin District (eastern Iberian Peninsula). The data were collected with an equal effort sampling approach. Univariate habitat suitability curves were built with a data-driven process for depth, mean velocity and substrate classes; three types of data-driven fuzzy models were generated with the FISH software: two models of presence-absence and a model of abundance. FISH applies a hill-climbing algorithm to optimize the fuzzy rules. A hydraulic model was calibrated with the tool River-2D in a segment of the Cabriel River (Jucar River Basin). The fuzzy-logic models and three methods to produce a suitability index from the three univariate curves were applied to evaluate the river habitat in the tool CASiMiR©. The comparison of results was based on the spatial arrangement of habitat suitability and the curves of weighted usable area versus discharge. The differences were relevant in different aspects, e.g. in the estimated minimum environmental flow according to the Spanish legal norm for hydrological planning. This work demonstrates the impact of the model's selection on the habitat suitability modelling and the assessment of environmental flows, based on an objective data-driven procedure; the conclusions are important for the water management in the Jucar River Basin and other river systems in Europe, where the environmental flows are a keystone for the achievement of the goals established

  4. Does dispersal from landlocked trout explain the coexistence of resident and migratory trout females in a small stream?

    DEFF Research Database (Denmark)

    Pettersson, J.C.E.; Hansen, Michael Møller; Bohlin, T.

    2001-01-01

    The hypothesis that stream-resident females of brown trout Salmo trutta occurring in sympatry with sea-migrant females in a small stream were immigrants from an up-stream allopatric landlocked population was rejected. Genetic differentiation was not detected between the sympatric forms whereas...... the landlocked population into the down-stream population, However. it cannot be precluded that a modest degree of gene Row takes place from the landlocked population and that this may play a role in maintaining the two co-existing life-history forms among females in the down-stream population. (C) 2001...

  5. Population Properties of Brown Dwarf Analogs to Exoplanets

    Science.gov (United States)

    Faherty, Jacqueline K.; Riedel, Adric R.; Cruz, Kelle L.; Gagne, Jonathan; Filippazzo, Joseph C.; Lambrides, Erini; Fica, Haley; Weinberger, Alycia; Thorstensen, John R.; Tinney, C. G.; Baldassare, Vivienne; Lemonier, Emily; Rice, Emily L.

    2016-07-01

    We present a kinematic analysis of 152 low surface gravity M7-L8 dwarfs by adding 18 new parallaxes (including 10 for comparative field objects), 38 new radial velocities, and 19 new proper motions. We also add low- or moderate-resolution near-infrared spectra for 43 sources confirming their low surface gravity features. Among the full sample, we find 39 objects to be high-likelihood or new bona fide members of nearby moving groups, 92 objects to be ambiguous members and 21 objects that are non-members. Using this age-calibrated sample, we investigate trends in gravity classification, photometric color, absolute magnitude, color-magnitude, luminosity, and effective temperature. We find that gravity classification and photometric color clearly separate 5-130 Myr sources from >3 Gyr field objects, but they do not correlate one to one with the narrower 5-130 Myr age range. Sources with the same spectral subtype in the same group have systematically redder colors, but they are distributed between 1 and 4σ from the field sequences and the most extreme outlier switches between intermediate- and low-gravity sources either confirmed in a group or not. The absolute magnitudes of low-gravity sources from the J band through W3 show a flux redistribution when compared to equivalently typed field brown dwarfs that is correlated with spectral subtype. Low-gravity, late-type L dwarfs are fainter at J than the field sequence but brighter by W3. Low-gravity M dwarfs are >1 mag brighter than field dwarfs in all bands from J through W3. Clouds, which are a far more dominant opacity source for L dwarfs, are the likely cause. On color-magnitude diagrams, the latest-type, low-gravity L dwarfs drive the elbow of the L/T transition up to 1 mag redder and 1 mag fainter than field dwarfs at M J but are consistent with or brighter than the elbow at M W1 and M W2. We conclude that low-gravity dwarfs carry an extreme version of the cloud conditions of field objects to lower temperatures

  6. Local adaptation at the transcriptome level in brown trout: Evidence from early life history temperature genomic reaction norms

    DEFF Research Database (Denmark)

    Meier, Kristian; Hansen, Michael Møller; Normandeau, Eric;

    2014-01-01

    . These included genes involved in immune- and stress response. We observed less plasticity in the resident as compared to the anadromous populations, possibly reflecting that the degree of environmental heterogeneity encountered by individuals throughout their life cycle will select for variable level...... C) representing conditions encountered in the local environments. Global gene expression for fry at the stage of first feeding was analysed using a 32k cDNA microarray. The results revealed differences in gene expression between populations and temperatures and population × temperature interactions...

  7. Local adaptation at the transcriptome level in brown trout: Evidence from early life history temperature genomic reaction norms

    DEFF Research Database (Denmark)

    Meier, Kristian; Hansen, Michael Møller; Normandeau, Eric;

    2014-01-01

    reaction norms and significantly higher QST than FST among populations for two early life-history traits. In the present study we investigated if genomic reaction norm patterns were also present at the transcriptome level. Eggs from the three populations were incubated at two temperatures (5 and 8 degrees......, the latter indicating locally adapted reaction norms. Moreover, the reaction norms paralleled those observed previously at early life-history traits. We identified 90 cDNA clones among the genes with an interaction effect that were differently expressed between the ecologically divergent populations...... phenotypic plasticity at the transcriptome level. Our study demonstrates the usefulness of transcriptome approaches to identify genes with different temperature reaction norms. The responses observed suggest that populations may vary in their susceptibility to climate change....

  8. Estimating the spatial distribution of wintering little brown bat populations in the eastern United States

    Science.gov (United States)

    Russell, Robin E.; Tinsley, Karl; Erickson, Richard A.; Thogmartin, Wayne E.; Jennifer A. Szymanski,

    2014-01-01

    Depicting the spatial distribution of wildlife species is an important first step in developing management and conservation programs for particular species. Accurate representation of a species distribution is important for predicting the effects of climate change, land-use change, management activities, disease, and other landscape-level processes on wildlife populations. We developed models to estimate the spatial distribution of little brown bat (Myotis lucifugus) wintering populations in the United States east of the 100th meridian, based on known hibernacula locations. From this data, we developed several scenarios of wintering population counts per county that incorporated uncertainty in the spatial distribution of the hibernacula as well as uncertainty in the size of the current little brown bat population. We assessed the variability in our results resulting from effects of uncertainty. Despite considerable uncertainty in the known locations of overwintering little brown bats in the eastern United States, we believe that models accurately depicting the effects of the uncertainty are useful for making management decisions as these models are a coherent organization of the best available information.

  9. Diagnosing mechanisms of decline and planning for recovery of an endangered brown bear (Ursus arctos population.

    Directory of Open Access Journals (Sweden)

    Guillaume Chapron

    Full Text Available BACKGROUND: The usual paradigm for translocations is that they should not take place in declining populations until the causes(s of the decline has been reversed. This approach sounds intuitive, but may not apply in cases where population decline is caused by behavioral or demographic mechanisms that could only be reversed by translocation itself. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed a decade of field data for Pyrenean brown bears (Ursus arctos from two small populations: the growing Central population--created from a previous translocation and the endemic Western population--believed to be declining because of excessive human-caused mortality. We found that adult survival rates for both populations were as high as those observed for most other protected brown bear populations. However, the Western population had much lower reproductive success than the Central population. Adult breeding sex ratio was male-biased in the Western population and female-biased in the Central population. Our results exclude high anthropogenic mortality as a cause for population decline in the West but support low reproductive success, which could result from sexually selected infanticide induced by a male-biased adult sex ratio or inbreeding depression. Using a stochastic demographic model to compute how many bears should be released to ensure viability, we show that the Western population could recover provided adequate numbers of new females are translocated. CONCLUSIONS/SIGNIFICANCE: We suggest that a translocation could take place, even if the decline has not yet been reversed, if the translocation itself removes the biological mechanisms behind the decline. In our case, the ultimate cause of low reproductive success remained unknown (infanticide or inbreeding, but our proposed translocation strategies should eliminate the proximate cause (low reproductive success of the decline and ensure population recovery and viability.

  10. Marine effect of introduced salmonids: Prey consumption by exotic steelhead and anadromous brown trout in the Patagonian Continental Shelf

    Science.gov (United States)

    Ciancio, J.; Beauchamp, D.A.; Pascual, M.

    2010-01-01

    On the basis of stable isotope analysis, we estimated the marine diet of the most abundant anadromous salmonid species in Patagonian Atlantic basins. The results were coupled with bioenergetic and population models to estimate the consumption of food by salmonids and was compared with that by seabirds, the most abundant top predators in the area. Amphipods were the main salmonid prey, followed by sprat, silversides, squid, and euphausiids. The total consumption, even assuming large anadromous salmonid populations, represented <5% of the total consumption by seabirds. We also identified the particular seabird colonies and artisanal fisheries with which salmonid trophic interactions at a more local scale could be significant. ?? 2010, by the American Society of Limnology and Oceanography, Inc.

  11. Identifying causes for population decline of the brown hare (Lepus europaeus) in agricultural landscapes in Denmark

    DEFF Research Database (Denmark)

    Jensen, Trine-Lee Wincentz

    proportions in game bags have dropped significantly since the 1950ies. Simple matrix population models with variable juvenile recruitment predict the similar population growth rates as actually observed in the annual bag records. The model substantiates the supposition that declines in the Danish hare......In recent decades the brown hare (Lepus europaeus) population in Denmark has undergone a substantial decline, but proximate causes are unknown and little is known about actual densities. In this thesis, hare populations are investigated with respect to age composition and reproductive parameters...... population are caused by reduced juvenile recruitment. Point transect counts are suitable and corrections for detection necessary, when monitoring hare populations, but work is still needed, before the effects of e.g. road avoidance on density estimates are fully clarified....

  12. Temporal changes in allele frequencies in a small marble trout Salmo marmoratus population threatened by extreme flood events.

    Science.gov (United States)

    Pujolar, J M; Vincenzi, S; Zane, L; Crivelli, A J

    2016-03-01

    The effect of extreme floods on the genetic composition of marble trout Salmo marmoratus living in Lipovscek, a tributary of the Soca River in Slovenia, which has been affected by multiple destructive flood events for centuries was investigated. By monitoring genetic variability during the period 2004-2011, apparent signatures of genetic erosion including a decline in observed and expected heterozygosities and allelic richness were observed. Contemporary effective population size was estimated between 11 and 55 individuals, which is congruent with census data. The data suggest asymmetric gene flow between the two sections of the river. The existence of substantial downstream migration (15-19%) was confirmed by paternity analysis. A small (1-3%) upstream migration was also suggested, which was confirmed by tagging data. Overall, low genetic diversity has not prevented the survival of the Lipovscek population, which might be a common feature of salmonid freshwater populations. PMID:26832308

  13. Density-Dependent Regulation of Brook Trout Population Dynamics along a Core-Periphery Distribution Gradient in a Central Appalachian Watershed

    OpenAIRE

    Huntsman, Brock M.; Petty, J. Todd

    2014-01-01

    Spatial population models predict strong density-dependence and relatively stable population dynamics near the core of a species' distribution with increasing variance and importance of density-independent processes operating towards the population periphery. Using a 10-year data set and an information-theoretic approach, we tested a series of candidate models considering density-dependent and density-independent controls on brook trout population dynamics across a core-periphery distribution...

  14. 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.

  15. Bacterial Community in Different Populations of Rice Brown Planthopper Nilaparvata lugens (Stål)

    Institute of Scientific and Technical Information of China (English)

    XU Hong-xing; ZHENG Xu-song; YANG Ya-jun; WANG Xin; YE Gong-yin; LU Zhong-xian

    2014-01-01

    The structures of bacterial communities in the brown planthopper (BPH) Nilaparvata lugens (Stål) from different geographic and resistant virulent populations were analyzed by using denatured gradient gel electrophoresis (DGGE). Results showed that the bacterial communities in BPH nymph from the first to the fifth instars varied with nymphal growth and development. The bacterial communities in the first-instar BPH nymph were similar to those in adults. Nine geographic BPH populations were divided into three groups based on the cluster analysis of DGGE fingerprint. The first group was from the Philippines;the second group was from Thailand and Hainan, Yunnan and Zhejiang provinces of China; and the third group was from Vietnam and Guangxi, Hunan and Jiangxi provinces of China. BPH populations adapted to different resistant rice varieties. The BPH populations from Mudgo (with resistant gene Bph1) and ASD7 (with resistant gene bph2) differed with those of the susceptible rice variety TN1.

  16. Study of population genetic polymorphism and gene flow rate in Indian snow trout, Schizothorax richardsonii fish of Himalaya, India.

    Science.gov (United States)

    Sivaraman, G K; Barat, A; Ali, S; Mahanta, P C

    2014-11-01

    The genetic polymorphism and gene flow rate among the Indian snow trout fish population S. richadsonii from three different locations viz., Chirapani stream of Champawat district, Kosi and Gola river of Nainital district, Uttarakhand State, India were assessed by employing twenty numbers of Randomly Amplified Polymorphic DNA (RAPD) markers. The overall percent polymorphisms among these three populations were 14.76 with 6.56, 4.92 and 3.28 in Chirapani, Kosi and Gola river population, respectively. Chirapani population had higher proportion of polymorphic loci as compared to the Kosi and Gola. The higher value of genetic distance (0.1565) was obtained between Chirapani and Gola population and the lower value of genetic distance was observed between Chirapani and Kosi (0.1058) river population. The cluster analysis revealed that in the formation of two clusters, one consisted of Chirapani and Kosi and the other was Gola fish population. Gst estimates among these populations showed some extent of homogeneity with lower genetic differentiation rate between populations and further suggested that higher tolerance to mutation, as expected that RAPD bands, arose from both coding and non-coding DNA regions. The findings revealed that the rate of gene flow in three populations seemed very low i.e. highly conserved its genetic diversity in their natural waterbodies and indicative of little migration among populations (geographically isolated and not the possibilities man made interventions/introduction of similar kind of fish species). It is further concluded that the Chirapani, Kosi and Gola river populations of S. richardsonii were being conserved naturally in their habitat and the species actual genetic potential were being maintained (adaptation to local climatic conditions, reproduction, production traits and disease resistance trait etc) in their natural habitat. PMID:25522514

  17. The SOPHIE search for northern extrasolar planets IX. Populating the brown dwarf desert

    CERN Document Server

    Wilson, P A; Santos, N C; Sahlmann, J; Montagnier, G; Astudillo-Defru, N; Boisse, I; Bouchy, F; Rey, J; Arnold, L; Bonfils, X; Bourrier, V; Courcol, B; Deleuil, M; Delfosse, X; Díaz, R F; Ehrenreich, D; Forveille, T; Moutou, C; Pepe, F; Santerne, A; Ségransan, D; Udry, S

    2016-01-01

    Radial velocity planet search surveys of nearby Solar-type stars have shown a strong deficit of brown dwarf companions within $\\sim5\\,\\mathrm{AU}$. There is presently no comprehensive explanation of this lack of brown dwarf companions, therefore, increasing the sample of such objects is crucial to understand their formation and evolution. Based on precise radial velocities obtained using the SOPHIE spectrograph at Observatoire de Haute-Provence we characterise the orbital parameters of $15$ companions to solar-type stars and constrain their true mass using astrometric data from the Hipparcos space mission. The nine companions not shown to be stellar in nature have minimum masses ranging from ~$13$ to $70\\,\\mathrm{M}_{\\mathrm{Jup}}$, and are well distributed across the planet/brown dwarf mass regime, making them an important contribution to the known population of massive companions around solar-type stars. We characterise six companions as stellar in nature with masses ranging from a minimum mass of $76 \\pm 4...

  18. The research of Recovery technology of natural populations of Dolly Varden trout%花羔红点鲑自然种群恢复技术研究

    Institute of Scientific and Technical Information of China (English)

    周旭昌; 赵莹

    2013-01-01

    This paper discusses the restoration mode of natural populations of the Dolly Varden trout spawning grounds and ecological habitats ,through constructed walls in the pond to make water stability in the forest basin of Wangqing county of Jilin province ,effectively increased the amount of Dolly varden trout ,improved natural populations of Dolly Varden trout spawning grounds and their ecological habitats environment ,itgreatly improved the Dolly Varden trout speed of recovery of natural populations.%本文讨论了花羔红点鲑自然种群产卵场和栖息地的生态修复模式,通过在吉林省汪清县南沟林场流域内修建稳汀子和稳水墙,有效的增加了花羔红点鲑在稳汀子中的数量,修复和改善了花羔红点鲑自然种群产卵场和栖息地的生态环境,极大地提高了花羔红点鲑自然种群的恢复速度。

  19. Net ground speed of downstream migrating radio-tagged Atlantic salmon ( Salmo salar L.) and brown trout ( Salmo trutta L.) smolts in relation to environmental factors

    DEFF Research Database (Denmark)

    Aarestrup, Kim; Nielsen, C.; Koed, Anders

    2002-01-01

    diel migration pattern of the radio tagged smolts was predominantly nocturnal in both species. Wild sea trout smolt migrated significantly faster than both the F1 trout and the introduced salmon. There was no correlation between net ground speed, gill Na+, K+-ATPase activity or fish length in any of...... tagged and released in the Danish River Lilleaa. The downstream migration of the different groups of fish was monitored by manual tracking and by three automatic listening stations. The downstream migration of radio tagged smolts of both species occurred concurrently with their untagged counterparts. The...

  20. Genetic and Phenotype [Phenotypic] Catalog of Native Resident Trout of the interior Columbia River Basin : FY-99 Report : Populations of the Pend Oreille, Kettle, and Sanpoil River Basins of Colville National Forest.

    Energy Technology Data Exchange (ETDEWEB)

    Trotter, Patrick C.

    2001-05-01

    The 1994 Fish and Wildlife Program of the Northwest Power Planning Council specifies the recovery and preservation of population health of native resident fishes of the Columbia River Basin. Among the native resident species of concern are interior rainbow trout of the Columbia River redband subspecies Oncorhynchus mykiss gairdneri 1 and westslope cutthroat trout O. clarki lewisi. The westslope cutthroat trout has been petitioned for listing under the U. S. Endangered Species Act (American Wildlands et al. 1997). Before at-risk populations can be protected, their presence and status must be established. Where introgression from introduced species is a concern, as in the case of both westslope cutthroat trout and redband rainbow trout, genetic issues must be addressed as well. As is true with native trout elsewhere in the western United States (Behnke 1992), most of the remaining pure populations of these species in the Columbia River Basin are in relatively remote headwater reaches. The objective of this project is to photo-document upper Columbia Basin native resident trout populations in Washington, and to ascertain their species or subspecies identity and relative genetic purity using a nonlethal DNA technique. FY-99 was year two of a five-year project in which we conducted field visits to remote locations to seek out and catalog these populations. In FY-99 we worked in collaboration with the Colville National Forest and Kalispel Indian Tribe to catalog populations in the northeastern corner of Washington State.

  1. Genetic variation for growth rate, feed conversion efficiency, and disease resistance exists within a farmed population of rainbow trout

    DEFF Research Database (Denmark)

    Henryon, Mark; Jokumsen, Alfred; Berg, Peer;

    2002-01-01

    The objective of this study was to test that additive genetic (co)variation for survival, growth rate, feed conversion efficiency, and resistance to viral haemorrhagic septicaemia (VHS) exists within a farmed population of rainbow trout. Thirty sires and 30 dams were mated by a partly factorial...... on days 52, 76, 96, 123, 157, 185, and 215, and body length on days 52 and 215); feed conversion efficiency between days 52-215, 52-76, 77-96, 97-123, 124-157, 158-185, and 186-215, and VHS resistance. REML estimates of additive genetic variation for the body weights, body lengths, and feed conversion...... efficiencies were obtained by fitting univariate linear (reduced) animal models. Additive genetic variation for VHS resistance was estimated by fitting a Weibull, sire-dam frailty model to time until death of fish challenged with VHS. Genetic correlations were estimated among the body weights, body length...

  2. 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

  3. HABITAT USE BY NATIVE AND STOCKED TROUT (SALMO TRUTTA L. IN TWO NORTHEAST STREAMS, PORTUGAL

    Directory of Open Access Journals (Sweden)

    TEIXEIRA A.

    2006-04-01

    Full Text Available Habitat use by stocked and native brown trout (Salmo trutta L. was assessed in two headwater streams of North-eastern Portugal. Underwater observations were made during the summer season in three successive years to evaluate the effect of supplemental trout stocking. Multivariate analysis techniques applied to data sets on microhabitat use were exploited to identify the focal elevation (distance of fish from the bottom, total depth and cover as the variables that contribute most to the discrimination between stocked and native trout. Preference curves computed for native and stocked trout of the same age (1+, showed a distinct pattern in their ability to explore the available microhabitat resources. Stocked trout tended to occupy deeper pools (total depth > 100 cm vs. 60-100 cm for native trout, holding higher focal elevations (140-160 cm vs. 22.5 cm and cover (combination of boulders and overhanging vegetation or undercut banks. Furthermore, a high poststocking movement of 80% hatchery-reared fish was verified just one month after their release, suggesting that stocking did not contribute to the sustainable populations in either stream, and is far from being an adequate management technique.

  4. Estimates of genetic diversity in the brown cattle population of Switzerland obtained from pedigree information.

    Science.gov (United States)

    Hagger, C

    2005-12-01

    The study investigates the genetic diversity present as well as its development in the Brown Cattle population of Switzerland from pedigree information. The population consisted of three subpopulations, the Braunvieh (BV), the original Braunvieh (OB) and the US-Brown Swiss (BS). The BV is a cross of OB with BS where crossing still continues. The OB is without any genetic influence of BS. The diversity measures effective population size, effective number of ancestors (explaining 99% of reference genome) and founder genome equivalents were calculated for 11 reference populations of animals born in a single year from 1992 onwards. The BS-subpopulation consisted of animals and their known ancestors which were used in the crossing scheme and was, therefore, quite small. The youngest animals were born in 2002, the oldest ones in the 1920s. Average inbreeding was by far the highest in BS, in spite of the lowest quality of pedigrees, and lowest in OB. Effective population size obtained from the difference between average inbreeding of offspring and their parents was, mostly due to the heavy use of few highly inbred BS-sires, strongly overestimated in some BV-reference populations. If this parameter was calculated from the yearly rate of inbreeding and a generation interval of 5 years, no bias was observed and ranking of populations from high to low was OB-BV-BS, i.e. equal to the other diversity parameters. The high genetic diversity found in OB was a consequence of the use of many natural service sires. Rate of decrease of effective number of ancestors was steeper in BV than OB was, however, equal for founder genome equivalents. Founder genome equivalents were more stable than effective population sizes calculated from the difference between average inbreeding of offspring and parents. The five most important ancestors contributed one-third of the 2002-reference genomes of BV and OB, in BV all were BS-sires. The relative amount of BS-genes in the BV-genome increased from

  5. Adult survival and population growth rate in Colorado big brown bats (Eptesicus fuscus)

    Science.gov (United States)

    O'Shea, T.J.; Ellison, L.E.; Stanley, T.R.

    2011-01-01

    We studied adult survival and population growth at multiple maternity colonies of big brown bats (Eptesicus fuscus) in Fort Collins, Colorado. We investigated hypotheses about survival using information-theoretic methods and mark-recapture analyses based on passive detection of adult females tagged with passive integrated transponders. We constructed a 3-stage life-history matrix model to estimate population growth rate (??) and assessed the relative importance of adult survival and other life-history parameters to population growth through elasticity and sensitivity analysis. Annual adult survival at 5 maternity colonies monitored from 2001 to 2005 was estimated at 0.79 (95% confidence interval [95% CI] = 0.77-0.82). Adult survival varied by year and roost, with low survival during an extreme drought year, a finding with negative implications for bat populations because of the likelihood of increasing drought in western North America due to global climate change. Adult survival during winter was higher than in summer, and mean life expectancies calculated from survival estimates were lower than maximum longevity records. We modeled adult survival with recruitment parameter estimates from the same population. The study population was growing (?? = 1.096; 95% CI = 1.057-1.135). Adult survival was the most important demographic parameter for population growth. Growth clearly had the highest elasticity to adult survival, followed by juvenile survival and adult fecundity (approximately equivalent in rank). Elasticity was lowest for fecundity of yearlings. The relative importances of the various life-history parameters for population growth rate are similar to those of large mammals. ?? 2011 American Society of Mammalogists.

  6. MICROLENSING DISCOVERY OF A POPULATION OF VERY TIGHT, VERY LOW MASS BINARY BROWN DWARFS

    Energy Technology Data Exchange (ETDEWEB)

    Choi, J.-Y.; Han, C. [Department of Physics, Institute for Astrophysics, Chungbuk National University, Cheongju 371-763 (Korea, Republic of); Udalski, A. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Sumi, T. [Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan); Gaudi, B. S.; Gould, A. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Bennett, D. P. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556-5670 (United States); Dominik, M. [SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS (United Kingdom); Beaulieu, J.-P. [Institut dAstrophysique de Paris, UMR7095 CNRS-Universite Pierre and Marie Curie, 98 bis boulevard Arago, F-75014 Paris (France); Tsapras, Y. [Las Cumbres Observatory Global Telescope Network, 6740B Cortona Drive, Goleta, CA 93117 (United States); Bozza, V. [INFN, Sezione di Napoli, I-80126 Napoli (Italy); Abe, F.; Furusawa, K.; Itow, Y. [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601 (Japan); Bond, I. A.; Ling, C. H. [Institute of Information and Mathematical Sciences, Massey University, Private Bag 102-904, North Shore Mail Centre, Auckland 0745 (New Zealand); Botzler, C. S.; Freeman, M. [Department of Physics, University of Auckland, Private Bag 92-019, Auckland 1001 (New Zealand); Chote, P. [School of Chemical and Physical Sciences, Victoria University, Wellington 6140 (New Zealand); Fukui, A. [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Asakuchi, Okayama 719-0232 (Japan); Collaboration: MOA Collaboration; OGLE Collaboration; muFUN Collaboration; MiNDSTEp Consortium; PLANET Collaboration; RoboNet Collaboration; and others

    2013-05-10

    Although many models have been proposed, the physical mechanisms responsible for the formation of low-mass brown dwarfs (BDs) are poorly understood. The multiplicity properties and minimum mass of the BD mass function provide critical empirical diagnostics of these mechanisms. We present the discovery via gravitational microlensing of two very low mass, very tight binary systems. These binaries have directly and precisely measured total system masses of 0.025 M{sub Sun} and 0.034 M{sub Sun }, and projected separations of 0.31 AU and 0.19 AU, making them the lowest-mass and tightest field BD binaries known. The discovery of a population of such binaries indicates that BD binaries can robustly form at least down to masses of {approx}0.02 M{sub Sun }. Future microlensing surveys will measure a mass-selected sample of BD binary systems, which can then be directly compared to similar samples of stellar binaries.

  7. 伊比利亚河共生的当年生鳟和埃布罗河鳟的夏季摄食关系%Summer feeding relationships of the co-occurring hatchling brown trout Salmo trutta and Ebro minnows Phoxinus bigrri in an Iberian river

    Institute of Scientific and Technical Information of China (English)

    Javier OSCOZ; Pedro M.LEUNDA; María C.ESCALA; Rafael MIRANDA

    2008-01-01

    The stomach content composition of 306 Ebro minnows and 185 hatchling brown trout captured in August (1996-1998) in the Larraun River (Ebro River Basin, Northern Spain) is described and compared in order to determine interspecific dietary overlap. Both species fed mainly on aquatic invertebrates. Feeding strategy plots showed that both species are generalist feeders with a heterogeneous diet. Additionally, the comparison between the stomach content and the benthic macroinvertebrate community revealed that both hatchling brown trout and Ebro minnows avoided Elmidae, Gammaridae, Caenidae, Baetidae and Leuctridae, instead showing a preference for Chironomidae, Heptageniidae and Trichoptera. Even though a two species was significant in the Larraun River, differential habitat use and diet plasticity could be minimizing the interspecific competition in river reaches where both species were co-dominant, allowing co-occurrence of these species in relatively high numbers. However, this adaptability and plasticity in Ebro minnows could be a threat to allopatric brown trout populations in rivers with limited trophic resources and limited habitat availability%1996-1998年8月在Larraun河(埃布罗河流域,西班牙北部)共捕获306尾埃布罗河(鱼岁)和185尾0龄的鳟,分析比较了胃含物组成,并测定了种间的食物重叠.食物的个数百分比组成表明两种都主要摄食水生无脊椎动物.摄食策略图显示两种都是摄食不同食物 种类的广食性种类.另外,比较胃含物和底栖大型无脊椎动物群落表明,0龄的鳟和埃布罗河(鱼岁)不摄食光螺科、钩虾科、细蜉科、 四节蜉科和卷襀科的物种,而喜食摇蚊科、五节蜉科和毛翅目物种.尽管简化的Morisitas指数表明Larraun河中这两种鱼之间的食物重叠是显著的,但由于栖息地不同和摄食的可塑性可以降低种间的竞争,使得该水域的这两种鱼能以相对较大的数量共存.然而,在食物资源和

  8. Evaluation of trap capture in a geographically closed population of brown treesnakes on Guam

    Science.gov (United States)

    Tyrrell, C.L.; Christy, M.T.; Rodda, G.H.; Yackel Adams, A.A.; Ellingson, A.R.; Savidge, J.A.; Dean-Bradley, K.; Bischof, R.

    2009-01-01

    1. Open population mark-recapture analysis of unbounded populations accommodates some types of closure violations (e.g. emigration, immigration). In contrast, closed population analysis of such populations readily allows estimation of capture heterogeneity and behavioural response, but requires crucial assumptions about closure (e.g. no permanent emigration) that are suspect and rarely tested empirically. 2. In 2003, we erected a double-sided barrier to prevent movement of snakes in or out of a 5-ha semi-forested study site in northern Guam. This geographically closed population of >100 snakes was monitored using a series of transects for visual searches and a 13 ?? 13 trapping array, with the aim of marking all snakes within the site. Forty-five marked snakes were also supplemented into the resident population to quantify the efficacy of our sampling methods. We used the program mark to analyse trap captures (101 occasions), referenced to census data from visual surveys, and quantified heterogeneity, behavioural response, and size bias in trappability. Analytical inclusion of untrapped individuals greatly improved precision in the estimation of some covariate effects. 3. A novel discovery was that trap captures for individual snakes consisted of asynchronous bouts of high capture probability lasting about 7 days (ephemeral behavioural effect). There was modest behavioural response (trap happiness) and significant latent (unexplained) heterogeneity, with small influences on capture success of date, gender, residency status (translocated or not), and body condition. 4. Trapping was shown to be an effective tool for eradicating large brown treesnakes Boiga irregularis (>900 mm snout-vent length, SVL). 5. Synthesis and applications. Mark-recapture modelling is commonly used by ecological managers to estimate populations. However, existing models involve making assumptions about either closure violations or response to capture. Physical closure of our population on a

  9. Y chromosome haplotype distribution of brown bears (Ursus arctos) in Northern Europe provides insight into population history and recovery.

    Science.gov (United States)

    Schregel, Julia; Eiken, Hans Geir; Grøndahl, Finn Audun; Hailer, Frank; Aspi, Jouni; Kojola, Ilpo; Tirronen, Konstantin; Danilov, Piotr; Rykov, Alexander; Poroshin, Eugene; Janke, Axel; Swenson, Jon E; Hagen, Snorre B

    2015-12-01

    High-resolution, male-inherited Y-chromosomal markers are a useful tool for population genetic analyses of wildlife species, but to date have only been applied in this context to relatively few species besides humans. Using nine Y-chromosomal STRs and three Y-chromosomal single nucleotide polymorphism markers (Y-SNPs), we studied whether male gene flow was important for the recent recovery of the brown bear (Ursus arctos) in Northern Europe, where the species declined dramatically in numbers and geographical distribution during the last centuries but is expanding now. We found 36 haplotypes in 443 male extant brown bears from Sweden, Norway, Finland and northwestern Russia. In 14 individuals from southern Norway from 1780 to 1920, we found two Y chromosome haplotypes present in the extant population as well as four Y chromosome haplotypes not present among the modern samples. Our results suggested major differences in genetic connectivity, diversity and structure between the eastern and the western populations in Northern Europe. In the west, our results indicated that the recovered population originated from only four male lineages, displaying pronounced spatial structuring suggestive of large-scale population size increase under limited male gene flow within the western subpopulation. In the east, we found a contrasting pattern, with high haplotype diversity and admixture. This first population genetic analysis of male brown bears shows conclusively that male gene flow was not the main force of population recovery.

  10. 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

  11. Prehibernation Energy Storage in Heilongjiang Brown Frogs (Rana amurensis) from Five Populations in North China

    Institute of Scientific and Technical Information of China (English)

    Wei CHEN; Tianpei GUAN; Lina REN; Dujuan HE; Ying WANG; Xin LU

    2015-01-01

    Energy storage is an important component in the life history of species that directly inlfuences survival and reproduction. The energetic demands of amphibian reproduction can differ between the sexes, with environmental conditions, reproductive pattern or process of the species, and depending upon the timing of breeding, and the reproductive season for a species. Surprisingly, comparative studies of pre-hibernation energy storage for anuran populations from different latitudes are relatively few in Asia, especially in China. Here we investigated the patterns of pre-hibernation energy storage of Heilongjiang brown frogsRana amurensis, based on ifve populations along a ifnely latitudinal gradient in north China (40.7–43.7°N). We found that pre-hibernation energy storage of the frogs did not show a clear latitudinal cline, but differed strongly between the sexes, with males depositing more energy reserves into the muscle and liver, whereas females accumulate more energy in the gonads. The sexual differences in energy storage may result from differential timing of energy allocation for reproduction.

  12. Population size structure indices and growth standards for Salmo (trutta trutta Linnaeus, 1758 in Central Italy

    Directory of Open Access Journals (Sweden)

    Pedicillo G.

    2010-10-01

    Full Text Available The purpose of this study was to provide reference data on the growth and population structure of brown trout Salmo (trutta trutta Linnaeus, in Central Italy. Standards for growth (percentiles and a standard growth model were developed from the von Bertalanffy growth model by using length-at-age data obtained from 122 sampling sites in the River Tiber basin. Length-frequency indices provide a numeric estimation for deviations of the population structure from a balanced population. We adapted the traditional North American Relative Stock Density (RSD and Proportional Stock Density (PSD indices to brown trout populations in Central Italy by means of two methods. In the first method, the benchmarks of length categories were established by using percentages applied to the largest individual in the dataset. In the second method, asymptotic length and size at maturity were used to define the length categories for index calculation. Both methods were tested on length-frequency data from 263 sampling sites in the River Tiber basin. The results showed that the PSD calculated by the first method provided a better insight into the population structures of brown trout. These results provide tools that will help ichthyologists and fish managers to compare the growth and population structure of brown trout throughout Central Italy.

  13. Genetic management of broodstock populations with DNA markers in rainbow trout

    Science.gov (United States)

    DNA markers are very useful for aquaculture and fisheries broodstock management. They have been used for parentage assignment when spawning families share common environments, and to evaluate genetic parameters in broodstock populations. The selective breeding program at the National Center for Cool...

  14. Fish populations in Plynlimon streams

    Directory of Open Access Journals (Sweden)

    D. T. Crisp

    1997-01-01

    Full Text Available In Plynlimon streams, brown trout (Salmo trutta L. are widespread in the upper Wye at population densities of 0.03 to 0.32 fish m-2 and show evidence of successful recruitment in most years. In the upper Severn, brown trout are found only in an area of c. 1670 -2 downstream of Blaenhafren Falls at densities of 0.03 to 0.24 fish -2 and the evidence suggests very variable year to year success in recruitment (Crisp & Beaumont, 1996. Analyses of the data show that temperature differences between afforested and unafforested streams may affect the rates of trout incubation and growth but are not likely to influence species survival. Simple analyses of stream discharge data suggest, but do not prove, that good years for recruitment in the Hafren population were years of low stream discharge. This may be linked to groundwater inputs detected in other studies in this stream. More research is needed to explain the survival of the apparently isolated trout population in the Hafren.

  15. High temperature determines the ups and downs of small brown planthopper Laodelphax striatellus population

    Institute of Scientific and Technical Information of China (English)

    Xiang-Dong Liu; Ai-Min Zhang

    2013-01-01

    Small brown planthopper,Laodelphax striatellus (Fallén) numbers usually drop sharply in the summer and revive quickly in the autumn.However,it is unclear whether and how the high temperature plays a role in this process.The effects of durations of heat exposure (33℃) on life-history traits were examined here.Exposure of adults for 1 day during the oviposition stage led to a very low survival of nymphs.The average longevity ofL.striatellus exposed for 1-31 days from oviposition was significantly longer than that of the control (27℃).Short-term (1-5 days) heat exposure of the third instar nymphs did not significantly influence eclosion,but exposure of the fourth instar nymphs significantly increased eclosion.Lifespan from egg to adult was significantly lengthened when the third instar nymphs were exposed to heat for 2-15 days,or the fourth instar were exposed for 10 days.The preoviposition period was prolonged by heat exposure of the third or fourth instar nymphs.Short-term heat exposure of less than 3 days of the third or fourth instar nymphs did not restrict fecundity,but when the exposure duration exceeded 5 days the total eggs per female and hatchability decreased.Exposure to high temperature increased the brachypter rate of adults.In summary,low survival and slowing development under heat exposure resulted in population decline in the summer,and the relatively high fecundity and brachypter rate led to quick revival in autumn.Temperature in the summer determines the rise and fall in numbers of L.striatellus.

  16. Growth strategy of heterotrophic bacterial population along successional sequence on spoil of brown coal colliery substrate

    Energy Technology Data Exchange (ETDEWEB)

    Kristufek, V.; Elhottova, D.; Chronakova, A.; Dostalkova, I.; Picek, T.; Kalcik, J. [Academy of Science in Czech Republic, Ceske Budejovice (Czech Republic). Inst. of Soil Biology

    2005-07-01

    The bacterial population of brown coal colliery spoil (Sokolov coal mining district, Czech Republic) was characterized by measuring viable bacterial biomass, the culturable to total cell ratio (C:T), colony-forming curve (CFC) analysis and species and/or biotype diversity. Bacterial representatives that differed in colony-forming growth (fast and/or slow growers) were used for growth-strategy investigation of heterotrophic bacteria. Spoil substrates from the surface (0-50 mm) and the mineral (100-150 mm) layers were sampled on 4 sites undergoing spontaneous succession corresponding to 1, 11, 21 and 43 years after deposition (initial, early, mid and late stages). The bacterial biomass of the surface layer increased during the initial and early stages with a maximum at mid stage and stabilized in the late stage while mineral layer biomass increased throughout the succession. The maxima of C:T ratios were at the early stage, minima at the late stage. Depending on the succession stage the C:T ratio was 1.5-2 times higher in the mineral than the surface layer of soil. An increase in the fraction of nonculturable bacteria was associated with the late succession stage. CFC analysis of the surface layer during a 3-d incubation revealed that the early-succession substrate contained more (75%) rapidly colonizing bacteria than successively older substrates. The culturable bacterial community of the mineral layer maintained a high genera and species richness of fast growers along the succession line in contrast to the surface layer community, where there was a maximum in the abundance of fast growers in the early stage. A markedly lower abundance of slow growers was observed in the mineral in contrast to the surface layer.

  17. Determination of the effects of fine-grained sediment and other limiting variables on trout habitat for selected streams in Wisconsin

    Science.gov (United States)

    Scudder, Barbara C.; Selbig, J.W.; Waschbusch, R.J.

    2000-01-01

    Two Habitat Suitability Index (HSI) models, developed by the U.S. Fish and Wildlife Service, were used to evaluate the effects of fine-grained (less than 2 millimeters) sediment on brook trout (Salvelinusfontinalis, Mitchill) and brown trout (Salmo trutta, Linnaeus) in 11 streams in west-central and southwestern Wisconsin. Our results indicated that fine-grained sediment limited brook trout habitat in 8 of 11 streams and brown trout habitat in only one stream. Lack of winter and escape cover for fry was the primary limiting variable for brown trout at 61 percent of the sites, and this factor also limited brook trout at several stations. Pool area or quality, in stream cover, streambank vegetation for erosion control, minimum flow, thalweg depth maximum, water temperature, spawning substrate, riffle dominant substrate, and dissolved oxygen also were limiting to trout in the study streams. Brook trout appeared to be more sensitive to the effects of fine-grained sediment than brown trout. The models for brook trout and brown trout appeared to be useful and objective screening tools for identifying variables limiting trout habitat in these streams. The models predicted that reduction in the amount of fine-grained sediment would improve brook trout habitat. These models may be valuable for establishing instream sediment-reduction goals; however, the decrease in sediment delivery needed to meet these goals cannot be estimated without quantitative data on land use practices and their effects on sediment delivery and retention by streams.

  18. TAILLE À 3 ANS DE LA TRUITE COMMUNE (SALMO TRUTTA L. DANS LES RIVIÈRES DES PYRÉNÉES FRANÇAISES : RELATIONS AVEC LES CARACTÉRISTIQUES MÉSOLOGIQUES ET INFLUENCE DES AMÉNAGEMENTS HYDROÉLECTRIQUES. TOTAL LENGTH OF AGE-3 BROWN TROUT (SALMO TRUTTA L. IN FRENCH PYRENEAN STREAMS : RELATIONSHIPS WITH ENVIRONMENTAL FACTORS AND INFLUENCE OF HYDROELECTRIC FACILITIES.

    Directory of Open Access Journals (Sweden)

    LAGARRIGUE T.

    2008-05-01

    Full Text Available La croissance de populations de truite commune (Salmo trutta L. a été étudiée sur 84 cours d'eau répartis sur l'ensemble de la chaîne des Pyrénées. Pour cela, des échantillons d'écailles ont été récoltés dans 215 sites situés à des altitudes comprises entre 185 et 2000 m, pour des largeurs variant de 1,2 à 60 m. La croissance des individus a été déterminée par scalimétrie. La longueur totale moyenne atteinte par les individus à l'âge de 3 ans a été retenue comme variable biologique. La taille moyenne à 3 ans des individus est fortement structurée par l'altitude, ce gradient altitudinal représentant en grande partie un gradient thermique. Elle est corrélée négativement avec l'altitude et la densité totale en truites communes et positivement avec la largeur du cours d'eau et la conductivité estivale. La nature du débit joue également un rôle important sur la croissance puisqu'à altitude et à température moyenne estivale équivalentes, la taille moyenne à 3 ans est significativement plus faible en site soumis à un débit réservé qu'en site à débit naturel. Selon la nature du débit, deux modèles prédictifs de la taille moyenne à 3 ans (T3 en fonction de l'altitude (ALT et de la largeur du cours d'eau (L ont été établis par régression multiple pas à pas : - sites à débit naturel : Log (T3 = 2.457 - 0.007 x sgrt ALT + 0.066 x Log (L 65.5 % (p The growth of brown trout (Salmo trutta L. populations has been studied on 84 streams distributed over the whole range of the Pyrenees. Samples of scales were collected in 215 sites located at altitudes ranging between 185 and 2000 m, for width varying from 1,2 to 60 m. The growth of individuals was determined by scale reading. The mean total length of age-3 trout was selected as the biological variable. The mean total length of age-3 trout was strongly structured by altitude, this altitudinal gradient mainly representing a thermal gradient. It is

  19. Genetic Dissection of Sympatric Populations of Brown Planthopper, Nilaparvata lugens (Stål, Using DALP-PCR Molecular Markers

    Directory of Open Access Journals (Sweden)

    M. A. Latif

    2012-01-01

    Full Text Available Direct amplified length polymorphism (DALP combines the advantages of a high-resolution fingerprint method and also characterizing the genetic polymorphisms. This molecular method was also found to be useful in brown planthopper, Nilaparvata lugens species complex for the analysis of genetic polymorphisms. A total of 11 populations of Nilaparvata spp. were collected from 6 locations from Malaysia. Two sympatric populations of brown planthopper, N. lugens, one from rice and the other from a weed grass (Leersia hexandra, were collected from each of five locations. N. bakeri was used as an out group. Three oligonucleotide primer pairs, DALP231/DALPR′5, DALP234/DALPR′5, and DALP235/DALPR′5 were applied in this study. The unweighted pair group method with arithmetic mean (UPGMA dendrogram based on genetic distances for the 11 populations of Nilaparvata spp. revealed that populations belonging to the same species and the same host type clustered together irrespective of their geographical localities of capture. The populations of N. lugens formed into two distinct clusters, one was insects with high esterase activities usually captured from rice and the other was with low esterase activities usually captured from L. hexandra. N. bakeri, an out group, was the most isolated group. Analyses of principal components, molecular variance, and robustness also supported greatly to the findings of cluster analysis.

  20. Metabolic fates and effects of nitrite in brown trout under normoxic and hypoxic conditions: blood and tissue nitrite metabolism and interactions with branchial NOS, Na+/K+-ATPase and hsp70 expression.

    Science.gov (United States)

    Jensen, Frank B; Gerber, Lucie; Hansen, Marie N; Madsen, Steffen S

    2015-07-01

    Nitrite secures essential nitric oxide (NO) bioavailability in hypoxia at low endogenous concentrations, whereas it becomes toxic at high concentrations. We exposed brown trout to normoxic and hypoxic water in the absence and presence of added ambient nitrite to decipher the cellular metabolism and effects of nitrite at basal and elevated concentrations under different oxygen regimes. We also tested hypotheses concerning the influence of nitrite on branchial nitric oxide synthase (NOS), Na(+)/K(+)-ATPase (nka) and heat shock protein (hsp70) mRNA expression. Basal plasma and erythrocyte nitrite levels were higher in hypoxia than normoxia, suggesting increased NOS activity. Nitrite exposure strongly elevated nitrite concentrations in plasma, erythrocytes, heart tissue and white muscle, which was associated with an extensive metabolism of nitrite to nitrate and to iron-nitrosylated and S-nitrosated compounds. Nitrite uptake was slightly higher in hypoxia than normoxia, and high internal nitrite levels extensively converted blood hemoglobin to methemoglobin and nitrosylhemoglobin. Hypoxia increased inducible NOS (iNOS) mRNA levels in the gills, which was overruled by a strong inhibition of iNOS expression by nitrite in both normoxia and hypoxia, suggesting negative-feedback regulation of iNOS gene expression by nitrite. A similar inhibition was absent for neuronal NOS. Branchial NKA activity stayed unchanged, but mRNA levels of the nkaα1a subunit increased with hypoxia and nitrite, which may have countered an initial NKA inhibition. Nitrite also increased hsp70 gene expression, probably contributing to the cytoprotective effects of nitrite at low concentrations. Nitrite displays a concentration-dependent switch between positive and negative effects similar to other signaling molecules. PMID:25908056

  1. Patterns of hybridization among cutthroat trout and rainbow trout in northern Rocky Mountain streams.

    Science.gov (United States)

    McKelvey, Kevin S; Young, Michael K; Wilcox, Taylor M; Bingham, Daniel M; Pilgrim, Kristine L; Schwartz, Michael K

    2016-02-01

    Introgressive hybridization between native and introduced species is a growing conservation concern. For native cutthroat trout and introduced rainbow trout in western North America, this process is thought to lead to the formation of hybrid swarms and the loss of monophyletic evolutionary lineages. Previous studies of this phenomenon, however, indicated that hybrid swarms were rare except when native and introduced forms of cutthroat trout co-occurred. We used a panel of 86 diagnostic, single nucleotide polymorphisms to evaluate the genetic composition of 3865 fish captured in 188 locations on 129 streams distributed across western Montana and northern Idaho. Although introgression was common and only 37% of the sites were occupied solely by parental westslope cutthroat trout, levels of hybridization were generally low. Of the 188 sites sampled, 73% contained ≤5% rainbow trout alleles and 58% had ≤1% rainbow trout alleles. Overall, 72% of specimens were nonadmixed westslope cutthroat trout, and an additional 3.5% were nonadmixed rainbow trout. Samples from seven sites met our criteria for hybrid swarms, that is, an absence of nonadmixed individuals and a random distribution of alleles within the sample; most (6/7) were associated with introgression by Yellowstone cutthroat trout. In streams with multiple sites, upstream locations exhibited less introgression than downstream locations. We conclude that although the widespread introduction of nonnative trout within the historical range of westslope cutthroat trout has increased the incidence of introgression, sites containing nonadmixed populations of this taxon are common and broadly distributed.

  2. Metabolic fates and effects of nitrite in brown trout under normoxic and hypoxic conditions: blood and tissue nitrite metabolism and interactions with branchial NOS, Na+/K+-ATPase and hsp70 expression

    DEFF Research Database (Denmark)

    Jensen, Frank Bo; Gerber, Lucie; Hansen, Marie Niemann;

    2015-01-01

    Nitrite secures essential nitric oxide (NO) bioavailability in hypoxia at low endogenous concentrations, whereas it becomes toxic at high concentrations. We exposed brown trout to normoxic and hypoxic water in the absence and presence of added ambient nitrite to decipher the cellular metabolism and...... were higher in hypoxia than normoxia, suggesting increased NOS activity. Nitrite exposure strongly elevated nitrite concentrations in plasma, erythrocytes, heart tissue and white muscle, which was associated with an extensive metabolism of nitrite to nitrate and to iron-nitrosylated and S...

  3. Microlensing discovery of a population of very tight, very low mass binary brown dwarfs

    DEFF Research Database (Denmark)

    Choi, J.-Y.; Han, C.; Udalski, A.;

    2013-01-01

    Although many models have been proposed, the physical mechanisms responsible for the formation of low-mass brown dwarfs (BDs) are poorly understood. The multiplicity properties and minimum mass of the BD mass function provide critical empirical diagnostics of these mechanisms. We present the disc...

  4. 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

  5. Genetic diversity of contemporary populations of Salmo trutta L. in the basin of the River Neretva, Bosnia and Herzegovina

    Directory of Open Access Journals (Sweden)

    Belma Kalamujic

    2015-11-01

    Full Text Available Across its cosmopolitan range, the survival of the local gene pool of wild brown trout, Salmo trutta L., is threatened due to habitat degradation, overexploitation, inadequate stocking and hybridization. In Bosnia and Herzegovina, brown trout reside in both, the Danube and the Adriatic river drainages. The aim of this study was to assess the contemporary genetic diversity of brown trout populations in the Neretva River basin and to detect the populations that could serve as a source of material for future revitalization projects. The control region of mitochondrial genome, LDH gene, 13 nuclear microsatellites as well as GP85 SNP were analyzed in a total of 335 specimens from the main course of the River Neretva and 11 of its tributaries. Sampling locations on tributaries were located in hardly accessible areas so to maximally reduce the possibility of previous stocking. Besides the indigenous Adriatic haplotype, the Danube and the Atlantic mtDNA haplotypes were detected, which clearly indicates that populations of brown trout in the Neretva river basin have been subject to translocation activities and stocking with allochthonous gene pool. The existence of individuals with Adriatic haplotype but microsatellite variants corresponding to the Danube and the Atlantic lineages, as well as the presence of obtusirostris haplotype, characteristic for soft-muzzled trout, clearly prove hybridization events. The frequency of almost 100% of the allele 167 (locus SsoSL417 in indigenous group clearly points to the possibility that this allele is correlated with the Neretva/Adriatic haplotype and could be used as a potential marker of autochthony. Though the gene pool of the Neretva brown trout has been highly compromised, there is still a real genetic basis for the successful revitalization of indigenous genetic resources, if the immediate and urgent actions are taken through joint activities of the government, public and private sectors (fisheries, and

  6. 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...

  7. The relative importance of direct and indirect effects of hunting mortality on the population dynamics of brown bears.

    Science.gov (United States)

    Gosselin, Jacinthe; Zedrosser, Andreas; Swenson, Jon E; Pelletier, Fanie

    2015-01-01

    There is increasing evidence of indirect effects of hunting on populations. In species with sexually selected infanticide (SSI), hunting may decrease juvenile survival by increasing male turnover. We aimed to evaluate the relative importance of direct and indirect effects of hunting via SSI on the population dynamics of the Scandinavian brown bear (Ursus arctos). We performed prospective and retrospective demographic perturbation analyses for periods with low and high hunting pressures. All demographic rates, except yearling survival, were lower under high hunting pressure, which led to a decline in population growth under high hunting pressure (λ = 0.975; 95% CI = 0.914-1.011). Hunting had negative indirect effects on the population through an increase in SSI, which lowered cub survival and possibly also fecundity rates. Our study suggests that SSI could explain 13.6% of the variation in population growth. Hunting also affected the relative importance of survival and fecundity of adult females for population growth, with fecundity being more important under low hunting pressure and survival more important under high hunting pressure. Our study sheds light on the importance of direct and indirect effects of hunting on population dynamics, and supports the contention that hunting can have indirect negative effects on populations through SSI. PMID:25392469

  8. Life+ Trout Project (LIFE12 NAT/IT/0000940) for the recovery and conservation of Mediterranean trout (Salmo trutta complex) in the central Apennines (Italy).

    OpenAIRE

    Vincenzo Caputo Barucchi; Antonella Carosi

    2015-01-01

    The Mediterranean brown trout (Salmo trutta complex) is one of the freshwater fish species complex at greater risk of extinction in the Mediterranean area. The introduction of alien invasive species and their interaction with the native fauna represent some of the major threats to the survival of this species (Caputo et al., 2004). Currently, the genetic integrity of the Mediterranean trout is being compromised by the introgressive hybridization with the Atlantic trout. This hybridization, wh...

  9. Variations in water temperature and implications for trout populations in the Upper Schoharie Creek and West Kill, New York, USA

    Science.gov (United States)

    George, Scott D.; Baldigo, Barry P.; Smith, Martyn J.; Mckeown, Donald M; Faulringer, Jason

    2016-01-01

    Water temperature is a key component of aquatic ecosystems because it plays a pivotal role in determining the suitability of stream and river habitat to most freshwater fish species. Continuous temperature loggers and airborne thermal infrared (TIR) remote sensing were used to assess temporal and spatial temperature patterns on the Upper Schoharie Creek and West Kill in the Catskill Mountains, New York, USA. Specific objectives were to characterize (1) contemporary thermal conditions, (2) temporal and spatial variations in stressful water temperatures, and (3) the availability of thermal refuges. In-stream loggers collected data from October 2010 to October 2012 and showed summer water temperatures exceeded the 1-day and 7-day thermal tolerance limits for trout survival at five of the seven study sites during both summers. Results of the 7 August 2012 TIR indicated there was little thermal refuge at the time of the flight. About 690,170 m2 of water surface area were mapped on the Upper Schoharie, yet only 0.009% (59 m2) was more than 1.0 °C below the median water surface temperature (BMT) at the thalweg and no areas were more than 2.0 °C BMT. On the West Kill, 79,098 m2 were mapped and 0.085% (67 m2) and 0.018% (14 m2) were BMT by 1 and 2 °C, respectively. These results indicate that summer temperatures in the majority of the study area are stressful for trout and may adversely affect growth and survival. Validation studies are needed to confirm the expectation that resident trout are in poor condition or absent from the downstream portion of the study area during warm-water periods.

  10. Phylogeny and population structure of brown rot- and Moko disease-causing strains of Ralstonia solanacearum phylotype II.

    Science.gov (United States)

    Cellier, G; Remenant, B; Chiroleu, F; Lefeuvre, P; Prior, P

    2012-04-01

    The ancient soilborne plant vascular pathogen Ralstonia solanacearum has evolved and adapted to cause severe damage in an unusually wide range of plants. In order to better describe and understand these adaptations, strains with very similar lifestyles and host specializations are grouped into ecotypes. We used comparative genomic hybridization (CGH) to investigate three particular ecotypes in the American phylotype II group: (i) brown rot strains from phylotypes IIB-1 and IIB-2, historically known as race 3 biovar 2 and clonal; (ii) new pathogenic variants from phylotype IIB-4NPB that lack pathogenicity for banana but can infect many other plant species; and (iii) Moko disease-causing strains from phylotypes IIB-3, IIB-4, and IIA-6, historically known as race 2, that cause wilt on banana, plantain, and Heliconia spp. We compared the genomes of 72 R. solanacearum strains, mainly from the three major ecotypes of phylotype II, using a newly developed pangenomic microarray to decipher their population structure and gain clues about the epidemiology of these ecotypes. Strain phylogeny and population structure were reconstructed. The results revealed a phylogeographic structure within brown rot strains, allowing us to distinguish European outbreak strains of Andean and African origins. The pangenomic CGH data also demonstrated that Moko ecotype IIB-4 is phylogenetically distinct from the emerging IIB-4NPB strains. These findings improved our understanding of the epidemiology of important ecotypes in phylotype II and will be useful for evolutionary analyses and the development of new DNA-based diagnostic tools.

  11. Phylogeny and population structure of brown rot- and Moko disease-causing strains of Ralstonia solanacearum phylotype II.

    Science.gov (United States)

    Cellier, G; Remenant, B; Chiroleu, F; Lefeuvre, P; Prior, P

    2012-04-01

    The ancient soilborne plant vascular pathogen Ralstonia solanacearum has evolved and adapted to cause severe damage in an unusually wide range of plants. In order to better describe and understand these adaptations, strains with very similar lifestyles and host specializations are grouped into ecotypes. We used comparative genomic hybridization (CGH) to investigate three particular ecotypes in the American phylotype II group: (i) brown rot strains from phylotypes IIB-1 and IIB-2, historically known as race 3 biovar 2 and clonal; (ii) new pathogenic variants from phylotype IIB-4NPB that lack pathogenicity for banana but can infect many other plant species; and (iii) Moko disease-causing strains from phylotypes IIB-3, IIB-4, and IIA-6, historically known as race 2, that cause wilt on banana, plantain, and Heliconia spp. We compared the genomes of 72 R. solanacearum strains, mainly from the three major ecotypes of phylotype II, using a newly developed pangenomic microarray to decipher their population structure and gain clues about the epidemiology of these ecotypes. Strain phylogeny and population structure were reconstructed. The results revealed a phylogeographic structure within brown rot strains, allowing us to distinguish European outbreak strains of Andean and African origins. The pangenomic CGH data also demonstrated that Moko ecotype IIB-4 is phylogenetically distinct from the emerging IIB-4NPB strains. These findings improved our understanding of the epidemiology of important ecotypes in phylotype II and will be useful for evolutionary analyses and the development of new DNA-based diagnostic tools. PMID:22286995

  12. Bull Trout Life History, Genetics, Habitat Needs, and Limiting Factors in Central and Northeast Oregon. Annual Report 1996.

    Energy Technology Data Exchange (ETDEWEB)

    Bellerud, Blane L.; Gunckel, Stephanie; Hemmingsen, Alan R.; Buchanan, David V.; Howell, Philip J.

    1997-10-01

    This study is part of a multi-year research project studying aspects of bull trout life history, ecology and genetics. This report covers the activities of the project in 1996. Results and analysis are presented in the following five areas: (1) analysis of the genetic structure of Oregon bull trout populations; (2) distribution and habitat use of bull trout and brook trout in streams containing both species; (3) bull trout spawning surveys; (4) summary and analysis of historical juvenile bull trout downstream migrant trap catches in the Grande Ronde basin; and (5) food habits and feeding behavior of bull trout alone and in sympatry with brook trout.

  13. Brown adipose tissue harbors a distinct sub-population of regulatory T cells.

    Directory of Open Access Journals (Sweden)

    Dasa Medrikova

    Full Text Available Regulatory T (Treg cells are critical determinants of both immune responses and metabolic control. Here we show that systemic ablation of Treg cells compromised the adaptation of whole-body energy expenditure to cold exposure, correlating with impairment in thermogenic marker gene expression and massive invasion of pro-inflammatory macrophages in brown adipose tissue (BAT. Indeed, BAT harbored a unique sub-set of Treg cells characterized by a unique gene signature. As these Treg cells respond to BAT activation upon cold exposure, this study defines a BAT-specific Treg sub-set with direct implications for the regulation of energy homeostasis in response to environmental stress.

  14. Hydrography - Class A Wild Trout Streams - points

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Class A streams are streams that support a population of wild (natural reproduction) trout of sufficient size and abundance to support a long-term and rewarding...

  15. Hydrography - Class A Wild Trout Streams

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Class A streams are streams that support a population of wild (natural reproduction) trout of sufficient size and abundance to support a long-term and rewarding...

  16. Overwintering of sea trout (Salmo trutta) in freshwater

    DEFF Research Database (Denmark)

    Thomsen, Dennis; Koed, Anders; Nielsen, Christian;

    2007-01-01

    Brown trout (Salmo trutta) show large phenotypic plasticity. Juveniles may reside in their native freshwater habitat until maturation or migrate into the ocean as 1- to 3-year-old smolts. Sea-going fish (sea trout) reside at sea for 2-3 years until migrating back to their native stream for reprod...

  17. 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.

  18. 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.

  19. Trout in the Classroom

    Science.gov (United States)

    Heath, Thomas

    2014-05-01

    Trout in the Classroom (TIC) is a conservation-oriented environmental education program for elementary, middle, and high school students. During the year each teacher tailors the program to fit his or her curricular needs. Therefore, each TIC program is unique. TIC has interdisciplinary applications in science, social studies, mathematics, language arts, fine arts, and physical education. In the program, students and teachers raise trout from fertilized eggs supplied by Virginia Department of Game and Inland Fisheries (VGIF) hatcheries, in aquariums equipped with special chillers designed to keep the water near 50 degrees F. The students make daily temperature measurements, and monitor pH, dissolved oxygen, conductivity, and ammonia levels. They record their data, plot trends, and make sure that the water quality is sufficient to support trout development. The fingerlings, which hatch in late October, are almost an inch and a half long by mid-January. And towards the end of the school year, students will release the fry into VGIF approved watersheds. TIC programs have been in place all across the country for more than 20 years, and are the result of numerous collaborations between teachers, volunteers, government agencies, and local organizations like Trout Unlimited. The programs were designed specifically for teachers who wanted to incorporate more environmental education into their curriculum. While the immediate goal of Trout in the Classroom is to increase student knowledge of water quality and cold water conservation, its long-term goal is to reconnect an increasingly urbanized population of youth to the system of streams, rivers, and watersheds that sustain them. Successful programs have helped: connect students to their local environments and their local watersheds; teach about watershed health and water quality, and; get students to care about fish and the environment. In Virginia, the TIC program is now in its 8th year. Over the past year, the program

  20. 腐植酸在褐鳟鱼鳃和肌肉抵抗镉中毒的组织病理学和生物化学作用%Histopathological and Biochemical Effects of Humic Acid Against Cadmium Toxicity in Brown Trout Gills and Muscles

    Institute of Scientific and Technical Information of China (English)

    Gonca Alak; Muhammed Atamanalp; Ahmet Topal; Harun Arslan; Ertan Oruç; Serdar Altun; 李双(译)

    2015-01-01

    It was biochemically and histopathologically investigated whether humic acid (HA) has protective effects on cadmium (Cd) toxicity on muscle and gills of brown trout. The brown trout were exposed to cadmium (2ppm) and/or humic acid (5ppm). For this purpose, levels of glutathione peroxidase (GPx), superoxide dismutase (SOD), malondi-aldehyde (MDA) was investigated in muscle and gills tissues of brown trout. The activities of GPx and SOD in the tis-sues of ifsh exposed to Cd was signiifcantly lower than the control groups (P0.05). Hovewer, humic acid did not affect biochemical damage in cadmium group. Cd caused a signiifcant increase in histopathological changes in muscle and gills tissues, but histopathological changes were lower in the muscle tissue of Cd+HA group. These results suggest that humic acid may counteract the cadmium toxicity in muscles tissue in histopathologic aspect.%为了探究腐植酸(HA)对褐鳟鱼鳃和肌肉在抵抗镉(Cd)中毒方面是否发挥积极作用,进行了组织病理学和生物化学方面的研究。试验中,褐鳟暴露在仅施加2 ppm镉,施加2 ppm镉加5 ppm腐植酸,仅施加5 ppm腐植酸的3种环境条件下,分别测定其鳃和肌肉组织的谷胱甘肽过氧化物酶(G P x)、超氧化物歧化酶(S O D)、丙二醛(M D A)水平。在含镉条件下,褐鳟组织中的G P x和S O D活性显著低于对照组(P0.05)。然而,腐植酸并未影响镉造成的生化伤害。镉对鱼鳃和肌肉组织造成明显的组织病理学变化,而在镉+腐植酸处理组中,肌肉组织病理学变化较小。这些结果表明,腐植酸可从组织病理学方面中和肌肉组织镉中毒。

  1. 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.

  2. A population genetics toolbox for the threatened canopy-forming brown seaweeds Cystoseira tamariscifolia and C. amentacea (Fucales, Sargassaceae)

    KAUST Repository

    Engelen, Aschwin H.

    2016-09-28

    The brown macroalga Cystoseira tamariscifolia is a foundation species along the northeastern Atlantic and western Mediterranean Sea. It occurs from lower intertidal rock pools to the shallow subtidal. Anthropogenic pollution and rising seawater temperatures can threaten its local distributions. In order to address impacts of historical and current environmental changes, to quantify effective dispersal and population connectivity, and to provide genetic tools for restoration and coastal management strategies, we have developed ten microsatellite markers, validated on 48 individuals from a single population. With 2–11 alleles per locus, the observed heterozygosity varied between 0.244 and 0.875. All of the developed microsatellites cross-amplified also on Cystoseira amentacea. The ten microsatellite loci developed here show high genetic diversity, making them useful for connectivity and population genetic studies aimed at small to large spatial scales, and provide essential insight for the development of conservation strategies for this important but threatened foundation species. © 2016 Springer Science+Business Media Dordrecht

  3. BASEMAP, BROWN COUNTY, WISCONSIN TROUT CREEK PMR

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — FEMA Framework Basemap datasets comprise six of the seven FGDC themes of geospatial data that are used by most GIS applications (Note: the seventh framework theme,...

  4. 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.

  5. Population dynamics of the brown alga Himanthalia elongata under harvesting pressure

    Science.gov (United States)

    Stagnol, Doriane; Michel, Renaud; Davoult, Dominique

    2016-06-01

    Through experimental harvesting, followed by a 12-month monitoring of demographic attributes, we tested the influence of harvesting on the population dynamics of Himanthalia elongata. We further explore the data to test the hypothesis that the canopy would exert a negative effect on the other developmental stages (intraspecific competition) throughout the recovery cycle of the population. This showed that the H. elongata canopy plays a marked seasonal role not by precluding the presence of other developmental stages but by delaying or preventing their growth and development. The removal of the canopy facilitates the transition from one developmental stage to another, eventually permitting a fast recovery of size structure in the population. This study allows us to integrate population dynamics and intraspecific relationships in our understanding of macroalgal recovery patterns.

  6. 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.

  7. 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.

  8. 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.

  9. Microsatellite analyses of the trout of northwest Mexico

    Science.gov (United States)

    Nielsen, J.L.; Sage, G.K.

    2001-01-01

    The trout of northwest Mexico represent an undescribed group of fish considered part of the Oncorhynchus mykiss (Pacific trout) complex of species and subspecies. Recent genetic studies have shown these fish to have important genetic diversity and a unique evolutionary history when compared to coastal rainbow trout. Increased levels of allelic diversity have been found in this species at the southern extent of its range. In this study we describe the trout in the Sierra Madre Occidental from the rios Yaqui, Mayo, Casas Grandes and de Bavispe, and their relationship to the more southern distribution of Mexican golden trout (O. chrysogaster) using 11 microsatellite loci. Microsatellite allelic diversity in Mexican trout was high with a mean of 6.6 alleles/locus, average heterozygosity = 0.35, and a mean Fst = 0.43 for all loci combined. Microsatellite data were congruent with previously published mtDNA results showing unique panmictic population structure in the Rio Yaqui trout that differs from Pacific coastal trout and Mexican golden trout. These data also add support for the theory of headwaters transfer of trout across the Continental Divide from tributaries of the Rio de Bavispe into the Rio Casas Grandes. Rio Mayo trout share a close genetic relationship to trout in Rio Yaqui, but sample sizes from the Rio Mayo prevent significant comparisons in this study. Microsatellite analyses show significant allelic frequency differences between Rio Yaqui trout and O. chrysogaster in Sinaloa and Durango Mexico, adding further support for a unique evolutionary status for this group of northwestern Mexican trout.

  10. 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...

  11. Molecular crosstalk between a chemical and a biological stressor and consequences on disease manifestation in rainbow trout

    Energy Technology Data Exchange (ETDEWEB)

    Burki, Richard [Centre for Fish and Wildlife Health, University of Bern, Laenggassstrasse 122, CH-3001 Bern (Switzerland); Krasnov, Aleksei [NOFIMA Marin, Postboks. 5010, 1432As (Norway); Bettge, Kathrin [Centre for Fish and Wildlife Health, University of Bern, Laenggassstrasse 122, CH-3001 Bern (Switzerland); Rexroad, Caird E. [National Center for Cool and Cold Water Aquaculture, USDA-ARS, 11876 Leetown Road, Kearneysville, WV 25430 (United States); Afanasyev, Sergey [Sechenov Institute of Evolutionary Physiology and Biochemistry, M. Toreza av. 44, Peterburg 194223 (Russian Federation); Antikainen, Miia [Institute of Applied Biotechnology, University of Kuopio (Finland); Burkhardt-Holm, Patricia [Man-Society-Environment, University of Basel, Vesalgasse 1, CH-4051 Basel (Switzerland); Wahli, Thomas [Centre for Fish and Wildlife Health, University of Bern, Laenggassstrasse 122, CH-3001 Bern (Switzerland); Segner, Helmut, E-mail: helmut.segner@vetsuisse.unibe.ch [Centre for Fish and Wildlife Health, University of Bern, Laenggassstrasse 122, CH-3001 Bern (Switzerland)

    2013-02-15

    The aim of the present study was to examine the molecular and organism reaction of rainbow trout, Oncorhynchus mykiss, to the combined impact of two environmental stressors. The two stressors were the myxozoan parasite, Tetracapsuloides bryosalmonae, which is the etiological agent of proliferative kidney disease (PKD) and a natural stressor to salmonid populations, and 17{beta}-estradiol (E2) as prototype of estrogen-active chemical stressors in the aquatic environment. Both stressors, the parasite and estrogenic contaminants, co-exist in Swiss rivers and are discussed as factors contributing to the decline of Swiss brown trout populations over the last decades. Using a microarray approach contrasting parasite-infected and non-infected rainbow trout at low or high estrogen levels, it was observed that molecular response patterns under joint exposure differed from those to the single stressors. More specifically, three major response patterns were present: (i) expression responses of gene transcripts to one stressor are weakened by the presence of the second stressor; (ii) expression responses of gene transcripts to one stressor are enhanced by the presence of the second stressor; (iii) expression responses of gene transcripts at joint treatment are dominated by one of the two stressors. Organism-level responses to concurrent E2 and parasite treatment - assessed through measuring parasite loads in the fish host and cumulative mortalities of trout - were dominated by the pathogen, with no modulating influence of E2. The findings reveal function- and level-specific responses of rainbow trout to stressor combinations, which are only partly predictable from the response to the single stressors.

  12. Molecular crosstalk between a chemical and a biological stressor and consequences on disease manifestation in rainbow trout

    International Nuclear Information System (INIS)

    The aim of the present study was to examine the molecular and organism reaction of rainbow trout, Oncorhynchus mykiss, to the combined impact of two environmental stressors. The two stressors were the myxozoan parasite, Tetracapsuloides bryosalmonae, which is the etiological agent of proliferative kidney disease (PKD) and a natural stressor to salmonid populations, and 17β-estradiol (E2) as prototype of estrogen-active chemical stressors in the aquatic environment. Both stressors, the parasite and estrogenic contaminants, co-exist in Swiss rivers and are discussed as factors contributing to the decline of Swiss brown trout populations over the last decades. Using a microarray approach contrasting parasite-infected and non-infected rainbow trout at low or high estrogen levels, it was observed that molecular response patterns under joint exposure differed from those to the single stressors. More specifically, three major response patterns were present: (i) expression responses of gene transcripts to one stressor are weakened by the presence of the second stressor; (ii) expression responses of gene transcripts to one stressor are enhanced by the presence of the second stressor; (iii) expression responses of gene transcripts at joint treatment are dominated by one of the two stressors. Organism-level responses to concurrent E2 and parasite treatment – assessed through measuring parasite loads in the fish host and cumulative mortalities of trout – were dominated by the pathogen, with no modulating influence of E2. The findings reveal function- and level-specific responses of rainbow trout to stressor combinations, which are only partly predictable from the response to the single stressors.

  13. Mitochondrial DNA differentiation between two forms of trout Salmo letnica, endemic to the Balkan Lake Ohrid, reflects their reproductive isolation.

    Science.gov (United States)

    Sell, J; Spirkovski, Z

    2004-12-01

    Mitochondrial haplotype diversity in sympatric populations of Ohrid trout, Salmo letnica was investigated by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of the mtDNA control region and ND1, ND3/4, ND5/6 segments. A 310 bp fragment at the 5' end, and a 340-572 bp fragment at the 3' end of the control region were sequenced from representatives of the populations studied. Based on pairwise comparison of the sequences, five new haplotypes were identified plus one identical with the brown trout Andalusian haplotype from the southern Iberian Peninsula. The combination of both RFLP and sequence data sets yielded a total of 10 composite haplotypes. A high degree of genetic subdivision between S. letnica typicus and S. letnica aestivalis populations was observed. The notion of a sympatric origin for the two morphs is discussed. Length variation of the mtDNA control region due to the presence of an 82 bp unit, tandemly repeated one to four times, in the region between the conserved sequence block-3 (CSB-3) and the gene for phenylalanine tRNA is reported. Further, we demonstrate that a single duplication of the approximately 82 bp repeat unit is a common element of the salmonid mitochondrial control region. The unique genetic structure of Ohrid trout represents a highly valuable genetic resource that deserves appropriate management and conservation. PMID:15548279

  14. Genetic Investigations Using Immuno-biochemical Markers in a Maramureş Brown Cattle Population

    Directory of Open Access Journals (Sweden)

    Nicoleta Isfan

    2011-05-01

    Full Text Available The study of the genetic markers and identifying new markers involves an increasing number of research projects in the fields of genetics of immunology, biochemical genetics, molecular genetics, quantity genetics and the genetic improvement of animals. Some studies on genes frequency determining the red cells specificity and for whey hemoglobin are approached in the present report. In this way, some blood factors, most of them belonging to B system (the most complex system in cattle have been evidenced. The lowest gene frequency was present in K factor (7%, and highest one in, O1, G’ , W and F1 (100%. In addition to basic importance on knowledge and determination of cattle population genetic structure for studied protein loci, another theme proposed to correlate hemoglobin type with some traits of economical importance: milk yield, fat and protein content, fat and protein yield. Higher performance was recorded by HbA/HbA individuals.

  15. A comparison between single exponential smoothing (SES, double exponential smoothing (DES, holt’s (brown and adaptive response rate exponential smoothing (ARRES techniques in forecasting Malaysia population

    Directory of Open Access Journals (Sweden)

    Ahmad Nazim Aimran

    2014-09-01

    Full Text Available This research develops techniques which are helpful in forecasting univariate time series data. The techniques used in this study are Single Exponential Smoothing (SES, Double Exponential Smoothing (DES, Holt’s (Brown and Adaptive Response Rate Exponential Smoothing (ARRES Techniques. For the purpose of this study, secondary data of Malaysia Population covering the period 1957 up to 2013 was obtained from the Department of Statistics Malaysia. From the result obtained, Holt’s method was found to be the best method to forecast the Malaysia population since it produces the lowest Mean Square Error (MSE value which is 38,273.3 compared to 210,480.29 for SES, 38,827.7 for DEB and 209,835.8 for ARRES techniques. Keywords: Univariate, Forecasting, Single Exponential Smoothing, Double Exponential Smoothing, And Adaptive Response Rate Exponential Smoothing, Holt’s (Brown.

  16. An epizootic among rainbow trout

    Science.gov (United States)

    1953-01-01

    An epizootic among rainbow trout (Salmo gairdnerii) in a private trout farm, resulting from a species of Ichthyosporidium that caused very high mortality rates in all ages of trout, reported from the State of Washington.

  17. Fatty acid binding protein 4 expression marks a population of adipocyte progenitors in white and brown adipose tissues.

    Science.gov (United States)

    Shan, Tizhong; Liu, Weiyi; Kuang, Shihuan

    2013-01-01

    Adipose tissues regulate metabolism, reproduction, and life span. The development and growth of adipose tissue are due to increases of both adipocyte cell size and cell number; the latter is mediated by adipocyte progenitors. Various markers have been used to identify either adipocyte progenitors or mature adipocytes. The fatty acid binding protein 4 (FABP4), commonly known as adipocyte protein 2 (aP2), has been extensively used as a marker for differentiated adipocytes. However, whether aP2 is expressed in adipogenic progenitors is controversial. Using Cre/LoxP-based cell lineage tracing in mice, we have identified a population of aP2-expressing progenitors in the stromal vascular fraction (SVF) of both white and brown adipose tissues. The aP2-lineage progenitors reside in the adipose stem cell niche and express adipocyte progenitor markers, including CD34, Sca1, Dlk1, and PDGFRα. When isolated and grown in culture, the aP2-expressing SVF cells proliferate and differentiate into adipocytes upon induction. Conversely, ablation of the aP2 lineage greatly reduces the adipogenic potential of SVF cells. When grafted into wild-type mice, the aP2-lineage progenitors give rise to adipose depots in recipient mice. Therefore, the expression of aP2 is not limited to mature adipocytes, but also marks a pool of undifferentiated progenitors associated with the vasculature of adipose tissues. Our finding adds to the repertoire of adipose progenitor markers and points to a new regulator of adipose plasticity.

  18. Evolutionary Genetics of Rainbow Trout, Parasalmo gairdnerii (Richardson)

    OpenAIRE

    Berg, William J.

    1987-01-01

    Starch-gel electrophoresis was used to obtain allozyme data from 114 populations of rainbow-series trout. Seventy-three alleles were segregating at 24 genetic loci. An additional seven loci were monomorphic in all populations. Eight genetically discrete intraspecific population-groups were identified and formal nomenclatural recognition of their subspecific status was suggested. The widespread coastal rainbow trout subspecies, Parasalmo gairdnerii gairdnerii was found to have higher levels of...

  19. Assembling a dual purpose TaqMan-based panel of single-nucleotide polymorphism markers in rainbow trout and steelhead (Oncorhynchus mykiss) for association mapping and population genetics analysis

    DEFF Research Database (Denmark)

    Hansen, Mette H H; Young, Sewall; Jørgensen, Hanne Birgitte Hede;

    2011-01-01

    We establish a TaqMan-based assay panel for genotyping single-nucleotide polymorphisms in rainbow trout and steelhead (Oncorhynchus mykiss). We develop 22 novel single-nucleotide polymorphism markers based on new steelhead sequence data and on assays from sister taxa. Additionally, we adapt 154...... previously developed markers to the TaqMan platform. At the beginning of this study, 59 SNPs with TaqMan assays were available to the scientific community. By adding 176 additional TaqMan assays to this number, we greatly expand the biological applications of TaqMan genotyping within both population genetics...... and quantitative genetics...

  20. Yellow fever impact on brown howler monkeys (Alouatta guariba clamitans) in Argentina: a metamodelling approach based on population viability analysis and epidemiological dynamics.

    Science.gov (United States)

    Moreno, Eduardo S; Agostini, Ilaria; Holzmann, Ingrid; Di Bitetti, Mario S; Oklander, Luciana I; Kowalewski, Martín M; Beldomenico, Pablo M; Goenaga, Silvina; Martínez, Mariela; Lestani, Eduardo; Desbiez, Arnaud L J; Miller, Philip

    2015-11-01

    In South America, yellow fever (YF) is an established infectious disease that has been identified outside of its traditional endemic areas, affecting human and nonhuman primate (NHP) populations. In the epidemics that occurred in Argentina between 2007-2009, several outbreaks affecting humans and howler monkeys (Alouatta spp) were reported, highlighting the importance of this disease in the context of conservation medicine and public health policies. Considering the lack of information about YF dynamics in New World NHP, our main goal was to apply modelling tools to better understand YF transmission dynamics among endangered brown howler monkey (Alouatta guariba clamitans) populations in northeastern Argentina. Two complementary modelling tools were used to evaluate brown howler population dynamics in the presence of the disease: Vortex, a stochastic demographic simulation model, and Outbreak, a stochastic disease epidemiology simulation. The baseline model of YF disease epidemiology predicted a very high probability of population decline over the next 100 years. We believe the modelling approach discussed here is a reasonable description of the disease and its effects on the howler monkey population and can be useful to support evidence-based decision-making to guide actions at a regional level.

  1. Yellow fever impact on brown howler monkeys (Alouatta guariba clamitans) in Argentina: a metamodelling approach based on population viability analysis and epidemiological dynamics

    Science.gov (United States)

    Moreno, Eduardo S; Agostini, Ilaria; Holzmann, Ingrid; Di Bitetti, Mario S; Oklander, Luciana I; Kowalewski, Martín M; Beldomenico, Pablo M; Goenaga, Silvina; Martínez, Mariela; Lestani, Eduardo; Desbiez, Arnaud LJ; Miller, Philip

    2015-01-01

    In South America, yellow fever (YF) is an established infectious disease that has been identified outside of its traditional endemic areas, affecting human and nonhuman primate (NHP) populations. In the epidemics that occurred in Argentina between 2007-2009, several outbreaks affecting humans and howler monkeys (Alouatta spp) were reported, highlighting the importance of this disease in the context of conservation medicine and public health policies. Considering the lack of information about YF dynamics in New World NHP, our main goal was to apply modelling tools to better understand YF transmission dynamics among endangered brown howler monkey (Alouatta guariba clamitans) populations in northeastern Argentina. Two complementary modelling tools were used to evaluate brown howler population dynamics in the presence of the disease: Vortex, a stochastic demographic simulation model, and Outbreak, a stochastic disease epidemiology simulation. The baseline model of YF disease epidemiology predicted a very high probability of population decline over the next 100 years. We believe the modelling approach discussed here is a reasonable description of the disease and its effects on the howler monkey population and can be useful to support evidence-based decision-making to guide actions at a regional level. PMID:26517499

  2. Effect of climate change on annual fluctuations in the population density of the brown marmorated stink bug (Hemiptera: Pentatomidae) in northern Japan.

    Science.gov (United States)

    Funayama, Ken

    2013-10-01

    The relationship between the population density of overwintering adults of the brown marmorated stink bug and the temperatures of each month during the preceding November to April was investigated in Akita Prefecture, northern Japan, from 1999 to 2012. The number of adults entering traps for overwintering at the monitored hibernation site differed considerably among years. There was a significant negative correlation between the increase ratio (the ratio of the number collected in the current year to the number collected in the previous year) and the mean daily maximum temperature of the preceding March and April. These results suggest that the proportion of surviving adult brown marmorated stink bug may be higher when temperatures in early spring (March and April) are lower, as the postoverwintering adults may need to survive without food for a shorter period of time.

  3. Effect of climate change on annual fluctuations in the population density of the brown marmorated stink bug (Hemiptera: Pentatomidae) in northern Japan.

    Science.gov (United States)

    Funayama, Ken

    2013-10-01

    The relationship between the population density of overwintering adults of the brown marmorated stink bug and the temperatures of each month during the preceding November to April was investigated in Akita Prefecture, northern Japan, from 1999 to 2012. The number of adults entering traps for overwintering at the monitored hibernation site differed considerably among years. There was a significant negative correlation between the increase ratio (the ratio of the number collected in the current year to the number collected in the previous year) and the mean daily maximum temperature of the preceding March and April. These results suggest that the proportion of surviving adult brown marmorated stink bug may be higher when temperatures in early spring (March and April) are lower, as the postoverwintering adults may need to survive without food for a shorter period of time. PMID:24224257

  4. Assessment of genetic correlation between bacterial cold water disease resistance and spleen index in a domesticated population of rainbow trout: Identification of QTL on chromosome Omy19

    Science.gov (United States)

    Selective breeding of animals for increased disease resistance is an effective strategy to reduce mortality in aquaculture. However, implementation of selective breeding programs is limited by an incomplete understanding of host resistance traits. We previously reported results of a rainbow trout ...

  5. Genetic Diversity of Brown Trout Populations Using Mitochondrial Markers In Relatively Similar Geographical and Ecological Conditions – a Carpathian Case Study

    Directory of Open Access Journals (Sweden)

    Popa Gina-Oana

    2013-12-01

    Full Text Available Analiza diversităţii genetice cu ajutorul markerilor mitocondriali, a unor populaţii de păstrav comun aflate în condiţii geografice şi ecologice relativ similare în Munţii Carpaţi.

  6. HABITAT USE BY NATIVE AND STOCKED TROUT (SALMO TRUTTA L.) IN TWO NORTHEAST STREAMS, PORTUGAL

    OpenAIRE

    Teixeira, A; CORTES R. M.V.; D. Oliveira

    2006-01-01

    Habitat use by stocked and native brown trout (Salmo trutta L.) was assessed in two headwater streams of North-eastern Portugal. Underwater observations were made during the summer season in three successive years to evaluate the effect of supplemental trout stocking. Multivariate analysis techniques applied to data sets on microhabitat use were exploited to identify the focal elevation (distance of fish from the bottom), total depth and cover as the variables that contribute most to the disc...

  7. Genetic Structure Analysis of Three Cultured Populations of Rainbow Trout(Oncorhynchus mykiss) Based on MHC-DAB Gene Intron Sequence%基于MHC-DAB基因内含子序列的3种虹鳟养殖群体遗传结构分析

    Institute of Scientific and Technical Information of China (English)

    杨娟; 刘山东; 施海娜; 胡丹丹; 王建福; 宋超; 张久盘; 刘哲

    2013-01-01

    Oncorhynchus mykiss was cultured all over the world, this paper analyzed the genetic variation of MHC-DAB intron 2 sequences ( 308 bp) in Gansu golden trout, Donaldson rainbow trout and USA Golden trout using PCR-SSCP. 11 different nucleotide sequences(Ⅰ~Ⅺ) were detected from 108 positive clones, a maximum of 4 alleles were amplified from one single individual. Allele Ⅱ,Ⅲ andⅥwere presented in all the 3 populations. Ⅳwas only presented in Donaldson rainbow trout; Ⅶ only presented in Gansu golden trout; Ⅸ, Ⅹ and Ⅺ only presented in Golden trout. In Gansu golden trout, Donaldson rainbow trout and Golden trout, the nucleotide polymorphic sites were 17, 19 and 22. The nucleotide diversities (Pi) were 0.005, 0.008 and 0.013. The average numbers of nucleotide differences ( K ) were 1. 200, 2. 000 and 3. 333, respectively. The genetic distance of Gansu golden trout and Donaldson rainbow trout was the smallest ( 0�231) , while that of Gansu golden trout and Golden trout was the largest (0.539). The genetic differentiation that compared any 2 of the 3 populations all up to the standard of population division (D>0.05). The genetic differentiation index (GST) of the 3 populations was 0.097, indicating that the variation mainly came from the inter-individual of the population.%虹鳟是当前全球性养殖品种,采用PCR-SSCP的方法,分析了甘肃金鳟、道氏虹鳟和美国金鳟三个虹鳟养殖群体各30个个体MHC-DAB基因第2内含子序列(308 bp)的遗传变异。108个阳性克隆经SSCP筛选及测序,共获得11种不同的核苷酸序列(Ⅰ~Ⅺ),单个个体最多存在4种等位基因。等位基因Ⅱ、Ⅲ、Ⅵ是三个群体共有的;Ⅳ仅存在于道氏虹鳟中;Ⅶ仅存在于甘肃金鳟中;Ⅸ、Ⅹ、Ⅺ仅存在于美国金鳟中。甘肃金鳟、道氏虹鳟、美国金鳟群体内核苷酸多态位点分别为17个、19个、22个,核苷酸多样性指数( Pi)分别为0.005、0.008、0

  8. 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

  9. 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

  10. Decrease of Population Divergence in Eurasian Perch (Perca fluviatilis) in Browning Waters: Role of Fatty Acids and Foraging Efficiency.

    Science.gov (United States)

    Scharnweber, Kristin; Strandberg, Ursula; Karlsson, Konrad; Eklöv, Peter

    2016-01-01

    Due to altered biogeochemical processes related to climate change, highly colored dissolved organic carbon (DOC) from terrestrial sources will lead to a water "brownification" in many freshwater systems of the Northern Hemisphere. This will create deteriorated visual conditions that have been found to affect habitat-specific morphological variations in Eurasian perch (Perca fluviatilis) in a previous study. So far, potential drivers and ultimate causes of these findings have not been identified. We conducted a field study to investigate the connection between morphological divergence and polyunsaturated fatty acid (PUFA) composition of perch from six lakes across a gradient of DOC concentration. We expected a decrease in the prevalence of PUFAs, which are important for perch growth and divergence with increasing DOC concentrations, due to the restructuring effects of DOC on aquatic food webs. In general, rate of morphological divergence in perch decreased with increasing DOC concentrations. Proportions of specific PUFAs (22:6n-3, 18:3n-3, 20:5n-3, and 20:4n-6) identified to primarily contribute to overall differences between perch caught in clear and brown-water lakes tended to be connected to overall decline of morphological divergence. However, no overall significant relationship was found, indicating no severe limitation of essential fatty acids for perch inhabiting brown water lakes. We further broaden our approach by conducting a laboratory experiment on foraging efficiency of perch. Therefore, we induced pelagic and littoral phenotypes by differences in habitat-structure and feeding mode and recorded attack rate in a feeding experiment. Generally, fish were less efficient in foraging on littoral prey (Ephemeroptera) when visual conditions were degraded by brown water color. We concluded that browning water may have a strong effect on the forager's ability to find particular food resources, resulting in the reduced development of evolutionary traits, such as

  11. 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.

  12. Yakima River Radio-Telemetry Study, Rainbow Trout, 1993 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Hockersmith, Eric E.

    1995-04-01

    Rainbow trout populations in the upper Yakima River Basin have increased due to reduced competition from declining populations of steelhead, chinook salmon, and coho salmon. Changing population abundances have increased the potential for interactions between rainbow trout and steelhead. In 1993, NMFS, in cooperation with WDW, proposed a 1-year radio-telemetry study to determine the spawning distribution, timing, and behavior of rainbow trout in the upper Yakima River Basin. Specific objectives were to: (1) Determine the spatial and temporal spawning distributions of rainbow trout in the upper Yakima River Basin. (2) Describe post-spawning behavior of rainbow trout in the upper Yakima River Basin. (3) Determine the magnitude and causes of mortalities to rainbow trout that were radio- tagged.

  13. 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.

  14. Trout Stream Special Regulations

    Data.gov (United States)

    Minnesota Department of Natural Resources — This layer shows Minnesota trout streams that have a special regulation as described in the 2006 Minnesota Fishing Regulations. Road crossings were determined using...

  15. Monitoring of fish species in the Lamone river: distribution and morphometric measures of the populations

    Directory of Open Access Journals (Sweden)

    Riccardo Bozzi

    2010-01-01

    Full Text Available Fish samplings were carried out monthly from spring to autumn during 2008, on the Lamone river and the Campigno stream by an electrofishing, in order to verify the presence of fish populations and the most common species represented. Barb, Barbus plebejus, Blageon, Leuciscus muticellus, Chub, Leuciscus cephalus, South European Nase, Chondrostoma genei were identified. A small population of Brown trout, Salmo trutta fario was also recognized. Barb is the most represented species in all the sites. The samplings highlight that Lamone river presented conditions suitable to fully guarantee the life of the fish populations.

  16. Study of Meat Physical-Chemical Composition of Three Trout Breeds Farmed in Salmonid Exploitations from Moldova

    Directory of Open Access Journals (Sweden)

    Cătălin Emilian NISTOR

    2014-11-01

    Full Text Available For all trout breeds, especially regarding brown trout, data from local and foreign literature consulted are less conclusive and sometimes controversial in terms of physical-chemical composition of trout meat, so our research represents a first for Romanian literature and aims to bring new information to enrich it.Our research aimed to evaluate the physical-chemical composition of the meat gathered from brook, rainbow and brown trout breed, by analyzing 50 individuals, 10 individuals in each batch (F1, F2, C1 C2 and I1, from two trout farms from Moldova, being determine the pH of meat, dry matter, content in proteins, lipids, ash and water/protein ratio for all three trout breeds. The obtained values for pH at warm ranged between 6.91 at batch F1, and 7.09 for batch I1. As regarding the pH at cold, this one had and descendant evolution ranging between: 6.78 for trout from batch F1 respectively a value of 6.88 for individuals from batch I1. The obtained values were between 23.95 and 27.12 for dry matter. Content in proteins recorded the best values (19.21% at individuals from batch F2, and content in lipids oscillated between 4.14% and 5.62%. The obtained values regarding physical-chemical composition highlighted that all trout breeds have a good nutritional value.

  17. 亚东鲑 Salmo trutta fario 肌肉营养成分分析和品质评价%Analysis and Evaluation of Muscular Nutrition in Brown Trout Salmo trutta fario

    Institute of Scientific and Technical Information of China (English)

    王芳; 户国; 周建设; 谷伟; 李宝海; 白庆利; 王炳谦

    2015-01-01

    N utritionalcom positions in m uscle of brow n troutSalmo trutta fario w ere analyzed by routine m ethods and evaluated by am ino acidsscore(AAS)and chem icalscore(CS).The resultsshow ed thatthe fresh m uscle contained m oisture of70.81% ,crude pro-tein22.63% ,crude fat4.91% and crude ash 1.80% .There w ere totalam ino acid (TA A)of69.51% ,totalessentialam ino acid(EA A) 28.86% and totaldelicious am ino acid (D A A)26.09% in dry m uscle w ith EA A /TA A of41.52% and EA A /N EA A of84.11% .Itw as clearthatthe tw o ratiosin the m uscle w ere in accord w ith the standard ofFA O /W H O(40% and 60% ).The A A S and C S revealed that m ethionine+cysteine and valine w ere the lim ited am ino acids,w ith essentialam ino acidsindex(EAAI)of85.54.A totalof12 kindsof fatty acidsw ere detected in the m uscle ofthe brow n trout,including 19.76% ofsaturated fatty acid (SFA),38.32% ofm onounsaturat-ed fatty acid(M U FA),38.98% ofpolyunsaturated fatty acid(PU FA),and up to 12.31% oftotalcontentofEPA and D H A .In conclu-sion,brow n troutisone ofthe fish w ith good nutritive value and culture values.%本实验通过测定亚东鲑 Salmo trutta fario 肌肉中常规成分、氨基酸含量及脂肪酸含量,评价其营养价值。结果表明:亚东鲑肌肉中水分、粗蛋白、粗脂肪和粗灰分含量分别为70.81%、22.63%、4.91%,和1.80%。除色氨酸水解外,亚东鲑肌肉中17种氨基酸的总量为69.51%,其中必需氨基酸为28.86%,占氨基酸总量的41.52%,符合 FAO/WHO 标准中必需氨基酸构成比例。4种鲜味氨基酸总量为26.09%,其中谷氨酸的含量最高,占鲜味氨基酸总量的41.47%。亚东鲑肌肉的限制性氨基酸为蛋氨酸+胱氨酸和缬氨酸。必需氨基酸指数为85.54。在亚东鲑肌肉中共检出12种脂肪酸,其中单不饱和脂肪酸含量为38.32%,多不饱和脂肪酸含量为38.98%,二十碳五烯酸和二十二碳六烯酸总量达到12.31%。结果表明:亚东鲑肌肉氨基

  18. Normative data for a computer-assisted version of the auditory three-consonant Brown-Peterson paradigm in the elderly French-Quebec population.

    Science.gov (United States)

    Callahan, Brandy L; Belleville, Sylvie; Ferland, Guylaine; Potvin, Olivier; Tremblay, Marie-Pier; Hudon, Carol; Macoir, Joël

    2014-01-01

    The Brown-Peterson task is used to assess verbal short-term memory as well as divided attention. In its auditory three-consonant version, trigrams are presented to participants who must recall the items in correct order after variable delays, during which an interference task is performed. The present study aimed to establish normative data for this test in the elderly French-Quebec population based on cross-sectional data from a retrospective, multi-center convenience sample. A total of 595 elderly native French-speakers from the province of Quebec performed the Memoria version of the auditory three-consonant Brown-Peterson test. For both series and item-by-item scoring methods, age, education, and, in most cases, recall after a 0-second interval were found to be significantly associated with recall performance after 10-second, 20-second, and 30-second interference intervals. Based on regression model results, equations to calculate Z scores are presented for the 10-second, 20-second and 30-second intervals and for each scoring method to allow estimation of expected performance based on participants' individual characteristics. As an important ceiling effect was observed at the 0-second interval, norms for this interference interval are presented in percentiles. PMID:24498960

  19. Normative data for a computer-assisted version of the auditory three-consonant Brown-Peterson paradigm in the elderly French-Quebec population.

    Science.gov (United States)

    Callahan, Brandy L; Belleville, Sylvie; Ferland, Guylaine; Potvin, Olivier; Tremblay, Marie-Pier; Hudon, Carol; Macoir, Joël

    2014-01-01

    The Brown-Peterson task is used to assess verbal short-term memory as well as divided attention. In its auditory three-consonant version, trigrams are presented to participants who must recall the items in correct order after variable delays, during which an interference task is performed. The present study aimed to establish normative data for this test in the elderly French-Quebec population based on cross-sectional data from a retrospective, multi-center convenience sample. A total of 595 elderly native French-speakers from the province of Quebec performed the Memoria version of the auditory three-consonant Brown-Peterson test. For both series and item-by-item scoring methods, age, education, and, in most cases, recall after a 0-second interval were found to be significantly associated with recall performance after 10-second, 20-second, and 30-second interference intervals. Based on regression model results, equations to calculate Z scores are presented for the 10-second, 20-second and 30-second intervals and for each scoring method to allow estimation of expected performance based on participants' individual characteristics. As an important ceiling effect was observed at the 0-second interval, norms for this interference interval are presented in percentiles.

  20. 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.

  1. 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

  2. Genetic Structure of Pacific Trout at the Extreme Southern End of Their Native Range.

    Science.gov (United States)

    Abadía-Cardoso, Alicia; Garza, John Carlos; Mayden, Richard L; García de León, Francisco Javier

    2015-01-01

    Salmonid fishes are cold water piscivores with a native distribution spanning nearly the entire temperate and subarctic northern hemisphere. Trout in the genus Oncorhynchus are the most widespread salmonid fishes and are among the most important fish species in the world, due to their extensive use in aquaculture and valuable fisheries. Trout that inhabit northwestern Mexico are the southernmost native salmonid populations in the world, and the least studied in North America. They are unfortunately also facing threats to their continued existence. Previous work has described one endemic species, the Mexican golden trout (O. chrysogaster), and one endemic subspecies, Nelson's trout (O. mykiss nelsoni), in Mexico, but previous work indicated that there is vastly more biodiversity in this group than formally described. Here we conducted a comprehensive genetic analysis of this important group of fishes using novel genetic markers and techniques to elucidate the biodiversity of trout inhabiting northwestern Mexico, examine genetic population structure of Mexican trout and their relationships to other species of Pacific trout, and measure introgression from non-native hatchery rainbow trout. We confirmed substantial genetic diversity and extremely strong genetic differentiation present in the Mexican trout complex, not only between basins but also between some locations within basins, with at least four species-level taxa present. We also revealed significant divergence between Mexican trout and other trout species and found that introgression from non-native rainbow trout is present but limited, and that the genetic integrity of native trout is still maintained in most locations. This information will help to guide effective conservation strategies for this important group of fishes. PMID:26509445

  3. Testing for multiple invasion routes and source populations for the invasive brown treesnake (Boiga irregularis) on Guam: implications for pest management

    Science.gov (United States)

    Richmond, Jonathan Q.; Wood, Dustin A.; Stanford, James W.; Fisher, Robert N.

    2014-01-01

    The brown treesnake (Boiga irregularis) population on the Pacific island of Guam has reached iconic status as one of the most destructive invasive species of modern times, yet no published works have used genetic data to identify a source population. We used DNA sequence data from multiple genetic markers and coalescent-based phylogenetic methods to place the Guam population within the broader phylogeographic context of B. irregularis across its native range and tested whether patterns of genetic variation on the island are consistent with one or multiple introductions from different source populations. We also modeled a series of demographic scenarios that differed in the effective size and duration of a population bottleneck immediately following the invasion on Guam, and measured the fit of these simulations to the observed data using approximate Bayesian computation. Our results exclude the possibility of serial introductions from different source populations, and instead verify a single origin from the Admiralty Archipelago off the north coast of Papua New Guinea. This finding is consistent with the hypothesis thatB. irregularis was accidentally transported to Guam during military relocation efforts at the end of World War II. Demographic model comparisons suggest that multiple snakes were transported to Guam from the source locality, but that fewer than 10 individuals could be responsible for establishing the population. Our results also provide evidence that low genetic diversity stemming from the founder event has not been a hindrance to the ecological success of B. irregularis on Guam, and at the same time offers a unique ‘genetic opening’ to manage snake density using classical biological approaches.

  4. Insecticide resistance monitoring and correlation analysis of insecticides in field populations of the brown planthopper Nilaparvata lugens (stål) in China 2012-2014.

    Science.gov (United States)

    Zhang, Xiaolei; Liao, Xun; Mao, Kaikai; Zhang, Kaixiong; Wan, Hu; Li, Jianhong

    2016-09-01

    The brown planthopper is a serious rice pest in China. Chemical insecticides have been considered a satisfactory means of controlling the brown planthopper. In the present study, we determined the susceptibility of twenty-one populations of Nilaparvata lugens to eleven insecticides by a rice-stem dipping method from 2012 to 2014 in eight provinces of China. These field-collected populations of N. lugens had developed high levels of resistance to imidacloprid (resistant ratio, RR=233.3-2029-fold) and buprofezin (RR=147.0-1222). Furthermore, N. lugens showed moderate to high levels of resistance to thiamethoxam (RR=25.9-159.2) and low to moderate levels of resistance to dinotefuran (RR=6.4-29.1), clothianidin (RR=6.1-33.6), ethiprole (RR=11.5-71.8), isoprocarb (RR=17.1-70.2), and chlorpyrifos (RR=7.4-30.7). In contrast, the susceptibility of N. lugens to etofenprox (RR=1.1-4.9), thiacloprid (RR=2.9-8.2) and acetamiprid (RR=2.7-26.2) remained susceptible to moderate levels of resistance. Significant correlations were detected between the LC50 values of imidacloprid and thiamethoxam, dinotefuran, buprofezin, and etofenprox, as well as between clothianidin and thiamethoxam, dinotefuran, ethiprole, acetamiprid, and thiacloprid. Similarly, significant correlations were observed between chlorpyrifos and etofenprox, acetamiprid and thiacloprid. Additionally, the activity of the detoxification enzymes of N. lugens showed a significant correlation with the log LC50 values of imidacloprid, dinotefuran and ethiprole. These results will be beneficial for effective insecticide resistance management strategies to prevent or delay the development of insecticide resistance.

  5. 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.

  6. Not All Larvae Stay Close to Home: Insights into Marine Population Connectivity with a Focus on the Brown Surgeonfish (Acanthurus nigrofuscus

    Directory of Open Access Journals (Sweden)

    Jeff A. Eble

    2011-01-01

    Full Text Available Recent reports of localized larval recruitment in predominately small-range fishes are countered by studies that show high genetic connectivity across large oceanic distances. This discrepancy may result from the different timescales over which genetic and demographic processes operate or rather may indicate regular long-distance dispersal in some species. Here, we contribute an analysis of mtDNA cytochrome b diversity in the widely distributed Brown Surgeonfish (Acanthurus nigrofuscus; N=560, which revealed significant genetic structure only at the extremes of the range (ΦCT=0.452; P<.001. Collections from Hawaii to the Eastern Indian Ocean comprise one large, undifferentiated population. This pattern of limited genetic subdivision across reefs of the central Indo-Pacific has been observed in a number of large-range reef fishes. Conversely, small-range fishes are often deeply structured over the same area. These findings demonstrate population connectivity differences among species at biogeographic and evolutionary timescales, which likely translates into differences in dispersal ability at ecological and demographic timescales. While interspecific differences in population connectivity complicate the design of management strategies, the integration of multiscale connectivity patterns into marine resource planning will help ensure long-term ecosystem stability by preserving functionally diverse communities.

  7. Homogeneous population of the brown alga Sargassum polycystum in Southeast Asia: possible role of recent expansion and asexual propagation.

    Directory of Open Access Journals (Sweden)

    Sze Wai Chan

    Full Text Available Southeast Asia has been known as one of the biodiversity hotspots in the world. Repeated glacial cycles during Pleistocene were believed to cause isolation of marine taxa in refugia, resulting in diversification among lineages. Recently, ocean current was also found to be another factor affecting gene flow by restricting larval dispersal in animals. Macroalgae are unique in having mode of reproduction that differs from that of animals. Our study on the phylogeographical pattern of the brown macroalga Sargassum polycystum using nuclear Internal Transcribed Spacer 2 (ITS2, plastidal RuBisCO spacer (Rub spacer and mitochondrial cytochrome oxidase subunit-III (Cox3 as molecular markers revealed genetic homogeneity across 27 sites in Southeast Asia and western Pacific, in sharp contrast to that revealed from most animal studies. Our data suggested that S. polycystum persisted in single refugium during Pleistocene in a panmixia pattern. Expansion occurred more recently after the Last Glacial Maximum and recolonization of the newly flooded Sunda Shelf could have involved asexual propagation of the species. High dispersal ability through floating fronds carrying developing germlings may also contribute to the low genetic diversity of the species.

  8. Wild Estonian and Russian sea trout (Salmo trutta) in Finnish coastal sea trout catches: results of genetic mixed-stock analysis.

    Science.gov (United States)

    Koljonen, Marja-Liisa; Gross, Riho; Koskiniemi, Jarmo

    2014-12-01

    For responsible fisheries management of threatened species, it is essential to know the composition of catches and the extent to which fisheries exploit weak wild populations. The threatened Estonian, Finnish and Russian sea trout populations in the Gulf of Finland are targets of mixed-stock fisheries. The fish may originate from rivers with varying production capacities, from different countries, and they may also have either a wild or hatchery origin. In order to resolve the composition of Finnish coastal sea trout catches, we created a standardized baseline dataset of 15 DNA microsatellite loci for 59 sea trout populations around the Gulf of Finland and tested its resolution for mixed-stock analysis of 1372 captured fish. The baseline dataset provided sufficient resolution for reliable mixture analysis at regional group level, and also for most of the individual rivers stocks. The majority (76-80%) of the total catch originated from Finnish sea trout populations, 6-9% came from Russian and 12-15% from Estonian populations. Nearly all Finnish trout in the catch were of hatchery origin, while the Russian and Estonian trout were mostly of wild origin. The proportion of fish in the Finnish catches that originated from rivers with natural production was at least one fifth (22%, 19-23%). Two different spotting patterns were observed among the captured trout, with a small and sparsely spotted form being markedly more common among individuals of Russian (28%) and Estonian origin (22%) than among fish assigned to a Finnish origin (0.7%).

  9. Recruitment in a Colorado population of big brown bats: Breeding probabilities, litter size, and first-year survival

    Science.gov (United States)

    O'Shea, T.J.; Ellison, L.E.; Neubaum, D.J.; Neubaum, M.A.; Reynolds, C.A.; Bowen, R.A.

    2010-01-01

    We used markrecapture estimation techniques and radiography to test hypotheses about 3 important aspects of recruitment in big brown bats (Eptesicus fuscus) in Fort Collins, Colorado: adult breeding probabilities, litter size, and 1st-year survival of young. We marked 2,968 females with passive integrated transponder (PIT) tags at multiple sites during 2001-2005 and based our assessments on direct recaptures (breeding probabilities) and passive detection with automated PIT tag readers (1st-year survival). We interpreted our data in relation to hypotheses regarding demographic influences of bat age, roost, and effects of years with unusual environmental conditions: extreme drought (2002) and arrival of a West Nile virus epizootic (2003). Conditional breeding probabilities at 6 roosts sampled in 2002-2005 were estimated as 0.64 (95% confidence interval [95% CI] = 0.530.73) in 1-year-old females, but were consistently high (95% CI = 0.940.96) and did not vary by roost, year, or prior year breeding status in older adults. Mean litter size was 1.11 (95% CI = 1.051.17), based on examination of 112 pregnant females by radiography. Litter size was not higher in older or larger females and was similar to results of other studies in western North America despite wide variation in latitude. First-year survival was estimated as 0.67 (95% CI = 0.610.73) for weaned females at 5 maternity roosts over 5 consecutive years, was lower than adult survival (0.79; 95% CI = 0.770.81), and varied by roost. Based on model selection criteria, strong evidence exists for complex roost and year effects on 1st-year survival. First-year survival was lowest in bats born during the drought year. Juvenile females that did not return to roosts as 1-year-olds had lower body condition indices in late summer of their natal year than those known to survive. ?? 2009 American Society of Mammalogists.

  10. 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

  11. Spawning Behaviour and the Softmouth Trout Dilemma

    Directory of Open Access Journals (Sweden)

    Esteve Manu

    2014-07-01

    Full Text Available Morphological, ecological and molecular data sets do not completely agree on the phylogenetic placement of the softmouth trout, Salmo (Salmothymus obtusirostris (Heckel. Molecules posit that softmouths are closely related to brown trout, Salmo trutta L. while some morphological, ecological and life history traits place them in the most basal position of the Salmoninae subfamily between grayling (Thymallus and lenok (Brachymystax. Here we add an additional source of data, behavioural characters based on the first reported observations of softmouth spawning. During spawning softmouth females present three important behaviours not found in the other Salmo members: they continually abandon their nests, rarely staying on them for periods over nine minutes; they expel different batches of eggs at the same nest at intervals of several minutes; and they do not cover their eggs immediately after spawning. These three behaviours are intriguing for two reasons: 1 they are possible homologous to behaviours found in grayling females; 2 when coupled to the nest digging behaviour-widespread in all the salmonines, including softmouths, they seem to be mal-adaptive.

  12. Resistance to re-challenge in the Brown Norway rat model of vasculitis is not always complete and may reveal separate effector and regulatory populations

    Science.gov (United States)

    Vinen, C S; Turner, D R; Oliveira, D B G

    2004-01-01

    Administration of mercuric chloride to Brown Norway rats results in T helper type 2 (Th2)- dominated autoimmunity characterized by high immunoglobulin E (IgE) concentrations, the production of multiple IgG autoantibodies, including those to glomerular basement membrane (GBM), arthritis and caecal vasculitis. After 14 days animals immunoregulate and auto-immunity resolves even if mercuric chloride injections are continued. In a third phase, if animals are re-challenged with mercuric chloride 6 weeks later, they show only attenuated autoimmunity with lower anti-GBM antibody concentrations and arthritis scores. Resistance to the induction of anti-GBM antibodies can also be achieved following an initial challenge with low-dose (one-tenth standard dose) mercuric chloride. We have now studied this resistant phase in more detail. We have shown, first, that following an initial full-dose mercuric chloride challenge, resistance also affects susceptibility to caecal vasculitis. Second, following an initial full-dose mercuric chloride challenge, the IgE response upon re-challenge is initially accelerated but subsequently enters a resistant phase and third, following an initial challenge with low-dose mercuric chloride, resistance is also seen to the induction of caecal vasculitis but is not seen in IgE serology (where results suggest competing effector and regulatory cell populations). Studying such regulatory phases in animal models of autoimmunity may be of benefit in the future in designing new therapies for human vasculitis. PMID:15379988

  13. The Sea Trout Year 1985

    OpenAIRE

    Fahy, E

    1986-01-01

    The wet year of 1985 yielded good catches to the rod and to commercial engines. Salmon were taken in reasonable numbers in the drift nets although only small numbers of sea trout were captured by this method. The wet angling season is thought to have provided productive fishing conditions contributing largely to a 22% increase over the previous year's landings of sea trout.

  14. Embryotoxicity of an extract from Great Lakes lake trout to rainbow trout and lake trout

    Energy Technology Data Exchange (ETDEWEB)

    Wright, P.J.; Tillitt, D.E. [National Biological Service, Columbia, MO (United States). Midwest Science Center

    1995-12-31

    Aquatic ecosystems such as the Great Lakes are known to be contaminated with chemicals that are toxic to fish. However, the role of these contaminants in reproductive failures of fishes, such as lake trout recruitment, has remained controvertible. It was the objective to evaluate dioxin-like embryotoxicity of a complex mixture of chemicals and predict their potential to cause the lack of recruitment in Great Lakes lake trout. Graded doses of a complex environmental extract were injected into eggs of both rainbow trout and lake trout. The extract was obtained from whole adult lake trout collected from Lake Michigan in 1988. The extract was embryotoxic in rainbow trout, with LD50 values for Arlee strain and Erwin strain of 33 eggEQ and 14 eggEQ respectively. The LOAEL for hemorrhaging, yolk-sac edema, and craniofacial deformities in rainbow trout were 2, 2, and 4 eggEQ, respectively. Subsequent injections of the extract into lake trout eggs were likewise embryotoxic, with an LD50 value of 7 eggEQ. The LOAEL values for the extract in lake trout for hemorrhaging, yolk-sac edema, and craniofacial deformities were 0.1, 1, and 2 eggEQ, respectively. The current levels of contaminants in lake trout eggs are above the threshold for hemorrhaging and yolk-sac edema. The results also support the use of an additive model of toxicity to quantify PCDDs, PCDFs, Non-o-PCBs, and Mono-o-PCBs in relation to early life stage mortality in Lake Michigan lake trout.

  15. Assessment of genetic correlation between bacterial cold water disease resistance and spleen index in a domesticated population of rainbow trout: identification of QTL on chromosome Omy19.

    Directory of Open Access Journals (Sweden)

    Gregory D Wiens

    Full Text Available Selective breeding of animals for increased disease resistance is an effective strategy to reduce mortality in aquaculture. However, implementation of selective breeding programs is limited by an incomplete understanding of host resistance traits. We previously reported results of a rainbow trout selection program that demonstrated increased survival following challenge with Flavobacterium psychrophilum, the causative agent of bacterial cold water disease (BCWD. Mechanistic study of disease resistance identified a positive phenotypic correlation between post-challenge survival and spleen somatic-index (SI. Herein, we investigated the hypothesis of a genetic correlation between the two traits influenced by colocalizing QTL. We evaluated the inheritance and calculated the genetic correlation in five year-classes of odd- and even-year breeding lines. A total of 322 pedigreed families (n = 25,369 fish were measured for disease resistance, and 251 families (n = 5,645 fish were evaluated for SI. Spleen index was moderately heritable in both even-year (h(2  = 0.56±0.18 and odd-year (h(2  = 0.60±0.15 lines. A significant genetic correlation between SI and BCWD resistance was observed in the even-year line (rg  = 0.45±0.20, P = 0.03 but not in the odd-year line (rg  = 0.16±0.12, P = 0.19. Complex segregation analyses of the even-year line provided evidence of genes with major effect on SI, and a genome scan of a single family, 2008132, detected three significant QTL on chromosomes Omy19, 16 and 5, in addition to ten suggestive QTL. A separate chromosome scan for disease resistance in family 2008132 identified a significant BCWD QTL on Omy19 that was associated with time to death and percent survival. In family 2008132, Omy19 microsatellite alleles that associated with higher disease resistance also associated with increased spleen size raising the hypothesis that closely linked QTL contribute to the correlation between

  16. 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.

  17. Population transcriptomics of life-history variation in the genus Salmo

    DEFF Research Database (Denmark)

    Giger, T.; Excoffier, L.; Amstutz, U.;

    2008-01-01

    design involving 180 cDNA microarray experiments, we measured gene-expression levels from 1098 transcript probes in 90 individuals originating from six brown trout (Salmo trutta) and one Atlantic salmon (Salmo salar) population, which follow either a migratory or a sedentary life history. We identified...... pathways potentially involved in the expression of life-history related phenotypic differences. Such differences included the down-regulation of genes involved in the respiratory system of future migratory individuals. In addition, we used linear discriminant analysis to identify a set of 12 genes...

  18. Plump Cutthroat Trout and Thin Rainbow Trout in a Lentic Ecosystem

    OpenAIRE

    Courtney, Joshua; Abbott, Jessica; Schmidt, Kerri; Courtney, Michael

    2012-01-01

    Background: Much has been written about introduced rainbow trout (Oncorhynchus mykiss) interbreeding and outcompeting cutthroat trout (Oncorhynchus clarkii). However, the specific mechanisms by which rainbow trout and their hybrids outcompete cutthroat trout have not been thoroughly explored, and the published data is limited to lotic ecosystems. Materials and Methods: Samples of rainbow trout and cutthroat trout were obtained from a lentic ecosystem by angling. The total length and weight of...

  19. Founding population size of an aquatic invasive species

    Science.gov (United States)

    Kalinowski, Steven T.; Muhlfeld, Clint C.; Guy, Christopher S.; Benjamin Cox

    2010-01-01

    Non-native species of fish threaten native fishes throughout North America, and in the Rocky Mountains, introduced populations of lake trout threaten native populations of bull trout. Effective management of lake trout and other exotic species require understanding the dynamics of invasion in order to either suppress non-native populations or to prevent their spread. In this study, we used microsatellite genetic data to estimate the number of lake trout that invaded a population of bull trout in Swan Lake, MT. Examination of genetic diversity and allele frequencies within the Swan Lake populations showed that most of the genes in the lake trout population are descended from two founders. This emphasizes the importance of preventing even a few lake trout from colonizing new territory.

  20. 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...

  1. Microlensing Binaries with Candidate Brown Dwarf Companions

    DEFF Research Database (Denmark)

    Shin, I.-G; Han, C.; Gould, A.;

    2012-01-01

    Brown dwarfs are important objects because they may provide a missing link between stars and planets, two populations that have dramatically different formation histories. In this paper, we present the candidate binaries with brown dwarf companions that are found by analyzing binary microlensing ...

  2. Impacts of Northern Pike on stocked Rainbow Trout in Pactola Reservoir, South Dakota

    Science.gov (United States)

    Scheibel, Natalie C.; Dembkowski, Daniel J.; Davis, Jacob L.; Chipps, Steven R.

    2016-01-01

    Establishment of nonnative Northern Pike Esox lucius in Pactola Reservoir, South Dakota, has prompted concern among biologists about the influence of this species on the lake’s intensively managed salmonid fisheries. Ancedotal information suggests that catch rates of Rainbow Trout Oncorhynchus mykiss have declined while mean size and abundance of Northern Pike has increased, although quantitative information on diet and growth of the Northern Pike population is lacking. To address potential interactions between Northern Pike and Rainbow Trout, we assessed size-dependent predation by Northern Pike on Rainbow Trout and determined the relative energetic contribution of stocked Rainbow Trout to Northern Pike growth using bioenergetics modeling. Stable isotopes combined with traditional diet analyses revealed that smaller Northern Pike (production costs of catchable-size Rainbow Trout revealed that annual economic losses ranged from US$15,259 to $24,801 per year. Over its lifespan, an age-10 Northern Pike was estimated to consume ~117 Rainbow Trout worth approximately $340. Thus, Northern Pike predation substantially influences salmonid management initiatives and is likely a primary factor contributing to reduced Rainbow Trout abundance and return to anglers in Pactola Reservoir. Strategies for reducing Northern Pike predation on Rainbow Trout include increasing the size of stocked fish or altering the timing and spatial distribution of stocking events.

  3. Larval long-toed salamanders incur nonconsumptive effects in the presence of nonnative trout

    Science.gov (United States)

    Kenison, Erin K.; Litt, Andrea R.; Pilliod, David; McMahon, Thomas E.

    2016-01-01

    Predators can influence prey directly through consumption or indirectly through nonconsumptive effects (NCEs) by altering prey behavior, morphology, and life history. We investigated whether predator-avoidance behaviors by larval long-toed salamanders (Ambystoma macrodactylum) in lakes with nonnative trout result in NCEs on morphology and development. Field studies in lakes with and without trout were corroborated by experimental enclosures, where prey were exposed only to visual and chemical cues of predators. We found that salamanders in lakes with trout were consistently smaller than in lakes without trout: 38% lower weight, 24% shorter body length, and 29% shorter tail length. Similarly, salamanders in protective enclosures grew 2.9 times slower when exposed to visual and olfactory trout cues than when no trout cues were present. Salamanders in trout-free lakes and enclosures were 22.7 times and 1.48 times, respectively, more likely to metamorphose during the summer season than those exposed to trout in lakes and/or their cues. Observed changes in larval growth rate and development likely resulted from a facultative response to predator-avoidance behavior and demonstrate NCEs occurred even when predation risk was only perceived. Reduced body size and growth, as well as delayed metamorphosis, could have ecological consequences for salamander populations existing with fish if those effects carry-over into lower recruitment, survival, and fecundity.

  4. Use of naturally occurring mercury to determine the importance of cutthroat trout to Yellowstone grizzly bears

    Science.gov (United States)

    Felicetti, L.A.; Schwartz, C.C.; Rye, R.O.; Gunther, K.A.; Crock, J.G.; Haroldson, M.A.; Waits, L.; Robbins, C.T.

    2004-01-01

    Spawning cutthroat trout (Oncorhynchus clarki (Richardson, 1836)) are a potentially important food resource for grizzly bears (Ursus arctos horribilis Ord, 1815) in the Greater Yellowstone Ecosystem. We developed a method to estimate the amount of cutthroat trout ingested by grizzly bears living in the Yellowstone Lake area. The method utilized (i) the relatively high, naturally occurring concentration of mercury in Yellowstone Lake cutthroat trout (508 ± 93 ppb) and its virtual absence in all other bear foods (6 ppb), (ii) hair snares to remotely collect hair from bears visiting spawning cutthroat trout streams between 1997 and 2000, (iii) DNA analyses to identify the individual and sex of grizzly bears leaving a hair sample, (iv) feeding trials with captive bears to develop relationships between fish and mercury intake and hair mercury concentrations, and (v) mercury analyses of hair collected from wild bears to estimate the amount of trout consumed by each bear. Male grizzly bears consumed an average of 5 times more trout/kg bear than did female grizzly bears. Estimated cutthroat trout intake per year by the grizzly bear population was only a small fraction of that estimated by previous investigators, and males consumed 92% of all trout ingested by grizzly bears.

  5. The marine life of sea trout (Salmo trutta)

    DEFF Research Database (Denmark)

    Del Villar, Diego

    -smolts as well as on the fish returning to freshwater after the marine stage. The results of my experiments increase the current knowledge of specific behavioural traits that sea trout displays during their marine life. Additionally, it provides new information on the early and late marine survival which......During my PhD. research project I have studied the marine migratory behaviour and survival of wild sea trout (Salmo trutta L.) juveniles when moving from freshwater to saltwater (i.e. smolts/post-smolts) in two different fjord systems. These studies are focused on the initial marine stage of post...... is needed for comprehensive management of sea trout populations in the area. The principal method used was telemetry (acoustic and PIT-telemetry) which enable studying migratory patterns of fish in the fjord (i.e. acoustic telemetry) and detecting the transitions from the marine to the riverine environments...

  6. Estrogenic effects of phytoestrogens in brown trout (Salmo trutta)

    DEFF Research Database (Denmark)

    Nielsen, Louise Marie; Holbech, Henrik; Bjerregaard, Poul;

    2010-01-01

    Phytoestrogens produced by agriculturally important crops such as clover, alfalfa and soya have the potential of leaching from the soil into streams. Concentrations of phytoestrogens in freshwater systems ranging from the low nanogram to low microgram per litre range have been demonstrated. However...

  7. Assessing effects of stocked trout on nongame fish assemblages in southern Appalachian Mountain streams

    Science.gov (United States)

    Weaver, D.; Kwak, Thomas J.

    2013-01-01

    Fisheries managers are faced with the challenge of balancing the management of recreational fisheries with that of conserving native species and preserving ecological integrity. The negative effects that nonnative trout species exert on native trout are well documented and include alteration of competitive interactions, habitat use, and production. However, the effects that nonnative trout may exert on nongame fish assemblages are poorly understood. Our objectives were to quantify the effects of trout stocking on native nongame fish assemblages intensively on one newly stocked river, the North Toe River, North Carolina, and extensively on other southern Appalachian Mountain streams that are annually stocked with trout. In the intensive study, we adopted a before-after, control-impact (BACI) experimental design to detect short-term effects on the nongame fish assemblage and found no significant differences in fish density, species richness, species diversity, or fish microhabitat use associated with trout stocking. We observed differences in fish microhabitat use between years, however, which suggests there is a response to environmental changes, such as the flow regime, which influence available habitat. In the extensive study, we sampled paired stocked and unstocked stream reaches to detect long-term effects from trout stocking; however, we detected no differences in nongame fish density, species richness, species diversity, or population size structure between paired sites. Our results revealed high inherent system variation caused by natural and anthropogenic factors that appear to overwhelm any acute or chronic effect of stocked trout. Furthermore, hatchery-reared trout may be poor competitors in a natural setting and exert a minimal or undetectable impact on native fish assemblages in these streams. These findings provide quantitative results necessary to assist agencies in strategic planning and decision making associated with trout fisheries, stream

  8. Movement of resident rainbow trout transplanted below a barrier to anadromy

    Science.gov (United States)

    Wilzbach, Margaret A.; Ashenfelter, Mark J.; Ricker, Seth J.

    2012-01-01

    We tracked the movement of resident coastal rainbow trout Oncorhynchus mykiss irideus that were experimentally transplanted below a migration barrier in a northern California stream. In 2005 and 2006, age-1 and older rainbow trout were captured above a 5-m-high waterfall in Freshwater Creek and individually marked with passive integrated transponder tags. Otolith microchemistry confirmed that the above-barrier trout were the progeny of resident rather than anadromous parents, and genetic analysis indicated that the rainbow trout were introgressed with cutthroat trout O. clarkii. At each of three sampling events, half of the tagged individuals (n = 22 and 43 trout in 2005 and 2006, respectively) were released 5 km downstream from the waterfall (approximately 10 km upstream from tidewater), and an equal number of tagged individuals were released above the barrier. Tagged individuals were subsequently relocated with stationary and mobile antennae or recaptured in downstream migrant traps, or both, until tracking ceased in October 2007. Most transplanted individuals remained within a few hundred meters of their release location. Three individuals, including one rainbow trout released above the waterfall, were last detected in the tidally influenced lower creek. Two additional tagged individuals released above the barrier were found alive in below-barrier reaches and had presumably washed over the falls. Two of seven tagged rainbow trout captured in downstream migrant traps had smolted and one was a presmolt. The smoltification of at least some individuals, coupled with above-barrier "leakage" of fish downstream, suggests that above-barrier resident trout have the potential to exhibit migratory behavior and to enter breeding populations of steelhead (anadromous rainbow trout) within the basin.

  9. 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.

  10. 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.

  11. Restoration and enhancement of Atlantic salmon populations: what we have learned from North Iberian rivers

    Directory of Open Access Journals (Sweden)

    Horreo J.L.

    2012-01-01

    Full Text Available Found on the southernmost edge of the species’ natural distribution, North Iberian Atlantic salmon populations are extremely vulnerable to environmental change. In the last few decades, associated with global indicators of climate change, these populations have been experiencing a sharp decline. Efforts have been made to address their decline, principally through stocking, supportive breeding and habitat restoration (enabling accessibility to upstream spawning sites. The efficiency of each of these measures has been different. In this study, focused on the river Sella containing one of the largest Spanish populations as a case study, we demonstrate that accessibility and habitat improvement have been the most efficient measures for increasing population size. Supportive breeding accounts for some level of population increase, but generally lower than 10%. Finally, our review suggests that stocking should be discarded as a restoration method because it encompasses threats to natural variation of Atlantic salmon and also the sympatric brown trout.

  12. Influence of barriers to movement on within-watershed genetic variation of coastal cutthroat trout

    Science.gov (United States)

    Wofford, John E.B.; Gresswell, Robert E.; Banks, M.A.

    2005-01-01

    Because human land use activities often result in increased fragmentation of aquatic and terrestrial habitats, a better understanding of the effects of fragmentation on the genetic heterogeneity of animal populations may be useful for effective management. We used eight microsatellites to examine the genetic structure of coastal cutthroat trout (Oncorhynchus clarki clarki) in Camp Creek, an isolated headwater stream in western Oregon. Our objectives were to determine if coastal cutthroat trout were genetically structured within streams and to assess the effects of natural and anthropogenic barriers on coastal cutthroat trout genetic variation. Fish sampling occurred at 10 locations, and allele frequencies differed significantly among all sampling sections. Dispersal barriers strongly influenced coastal cutthroat trout genetic structure and were associated with reduced genetic diversity and increased genetic differentiation. Results indicate that Camp Creek coastal cutthroat trout exist as many small, partially independent populations that are strongly affected by genetic drift. In headwater streams, barriers to movement can result in genetic and demographic isolation leading to reduced coastal cutthroat trout genetic diversity, and potentially compromising long-term population persistence. When habitat fragmentation eliminates gene flow among small populations, similar results may occur in other species.

  13. Annual variation of spawning Cutthroat Trout in a small Western USA stream: A case study with implications for the conservation of potamodromous trout life history diversity

    Science.gov (United States)

    Bennett, Stephen; Al-Chokhachy, Robert K.; Roper, Brett B.; Budy, Phaedra

    2014-01-01

    Little is known about the variability in the spatial and temporal distribution of spawning potamodromous trout despite decades of research directed at salmonid spawning ecology and the increased awareness that conserving life history diversity should be a focus of management. We monitored a population of fluvial–resident Bonneville Cutthroat Trout Oncorhynchus clarkii utah in a tributary to the Logan River, Utah, from 2006 to 2012 to gain insight into the distribution and timing of spawning and what factors may influence these spawning activities. We monitored Bonneville Cutthroat Trout using redd surveys with multiple observers and georeferenced redd locations. We documented an extended spawning period that lasted from late April to mid-July. The onset, median, and end of spawning was best predicted by the mean maximum water temperature during the first 13 weeks of the year (F = 130. 4, df = 5, R2 = 0.96, P Trout appeared to establish and defend a redd for up to 2 d, and spawning most often occurred between similar-sized individuals. Spawning surveys for potamodromous trout are an underutilized tool that could be used to better understand the distribution and timing of spawning as well as determine the size and trends of the reproducing portion of populations of management concern. Without efforts to document the diversity of this important aspect of potamodromous trout life history, prioritization of conservation will be problematic.

  14. BACTERIAL FLORA OF RAINBOW TROUT LARVAE AND FRY (ONCORHYNCHUS MYKISS

    Directory of Open Access Journals (Sweden)

    Damir Kapetanović

    2003-09-01

    Full Text Available There are no information in available literature about the structure of bacterial flora in rainbow trout larvae and fry in the first days of their lives. The objective of our work has been to follow bacteroflora between the third and the eighth week of their lives. During 35 days of experiment bacteroflora of rainbow trout has been examined, along with following physico–chemical characteristics of water quality as well as it’s influence on health. Samples for bacteriological examination were taken from gill, heart and kidney areas and innoculated on the plates. Bacterial colonies were examined macroscopically, slides with Gram staining, and afterwords biochemical tests were performed. For identification, APILAB Plus programme (bio Mérieux, France was used. Bacterial population of rainbow trout larvae and fry changed in dependence with their age. Physico–chemical characteristics of water ranged within optimal values. Most of bacterial colonies originated from gill isolates (64,4 %, than from heart (21,8 % and kidney areas (13,8 %. The bacterial flora of larvae in incubator was composed mostly of Gram–positive bacteria (75,1 %, genera: Renibacterium (25 %, Lactobacillus (16,7 %, Staphilococcus (16,7 % and Corynebacterium (16,7 %. The transfer of larvae from incubator into the pools resulted in reducing bacterial flora (–66,7 % after 45 minute stay in the pool. Gram–negative bacteria, which have been represented in larvae in incubator with low percent (24, 9 %, after the transfer of larvae to the pools became dominant and represented more than 95 % of rainbow trout larvae and fry bacterial flora. Flavobacterium, Acinetobacter and Yersinia were the predominant Gram–negative genera in larvae in incubator, whereas Aeromonas, Pseudomonas, Flavobacterium and Pasteurella were the main isolates from rainbow trout larvae and fry until the end of experiment. Bacterial flora of larvae in incubator mostly consists of Gram–positive bacteria

  15. Do Rainbow Trout and Their Hybrids Outcompete Cutthroat Trout in a Lentic Ecosystem?

    OpenAIRE

    Courtney, Joshua M.; Courtney, Amy C.; Courtney, Michael W.

    2013-01-01

    Much has been written about introduced rainbow trout interbreeding and outcompeting native cutthroat trout. However, specific mechanisms have not been thoroughly explored, and most data is limited to lotic ecosystems. Samples of Snake River cutthroat trout (Oncorhynchus clarkii bouvieri), the rainbow-cutthroat hybrid, the cutbow trout (Onchorhynchus mykiss x clarkii), and rainbow trout (Oncorhynchus mykiss), were obtained from a lentic ecosystem (Eleven Mile Reservoir, Colorado) by creel surv...

  16. Predation Risk and the Importance of Cover for Juvenile Rainbow Trout in Lentic Systems

    OpenAIRE

    Tabor, R. A.; Wurtsbaugh, Wayne A.

    1991-01-01

    Juvenile rainbow trout Oncorhynchus mykiss stocked in midelevation reservoirs in Utah inhabit shallow nearshore areas and are vulnerable to predation from piscivorous fish and birds. We determined the use and importance of nearshore habitats by (1) measuring habitat selection by, prey availability to, and feeding of juvenile rainbow trout in two reservoirs with populations of predators, and (2) measuring survival and growth rates in the presence and absence of cover in a pond experiment where...

  17. Genetic Structure of Pacific Trout at the Extreme Southern End of Their Native Range

    OpenAIRE

    Alicia Abadía-Cardoso; John Carlos Garza; Mayden, Richard L.; Francisco Javier García León

    2015-01-01

    Salmonid fishes are cold water piscivores with a native distribution spanning nearly the entire temperate and subarctic northern hemisphere. Trout in the genus Oncorhynchus are the most widespread salmonid fishes and are among the most important fish species in the world, due to their extensive use in aquaculture and valuable fisheries. Trout that inhabit northwestern Mexico are the southernmost native salmonid populations in the world, and the least studied in North America. They are unfortu...

  18. 33 CFR 117.337 - Trout River.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Trout River. 117.337 Section 117... OPERATION REGULATIONS Specific Requirements Florida § 117.337 Trout River. The draw of the CSX Railroad Bridge across the Trout River, mile 0.9 at Jacksonville, operates as follows: (a) The bridge is...

  19. Estimation of Population Size of Dentaria Enneaphyllos in the Vicinity of the Bełchatów Brown Coal Mine and the Attempt of its Metaplantation

    OpenAIRE

    Kurowski, Józef; Koczywąs, Ewelina; Pieńkowski, Michał

    2012-01-01

    The impact of anthropopressure on the flora in the vicinity of the Bełchatów Brown Coal Mine in Central Poland has been substantially strong. Consequently, certain changes in habitat conditions have been observed, leading to a decline in particular species stands. Mechanical damage, as well as the mine and power plant expansion have contributed to further species decline in the area. Ex situ conservation, e.g. metaplantation from native to secondary localities seems an efficient method of ens...

  20. 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

  1. Determining vaccination frequency in farmed rainbow trout using Vibrio anguillarum O1 specific serum antibody measurements.

    Directory of Open Access Journals (Sweden)

    Lars Holten-Andersen

    Full Text Available BACKGROUND: Despite vaccination with a commercial vaccine with a documented protective effect against Vibrio anguillarum O1 disease outbreaks caused by this bacterium have been registered among rainbow trout at Danish fish farms. The present study examined specific serum antibody levels as a valid marker for assessing vaccination status in a fish population. For this purpose a highly sensitive enzyme-linked immunosorbent assay (ELISA was developed and used to evaluate sera from farmed rainbow trout vaccinated against V. anguillarum O1. STUDY DESIGN: Immune sera from rainbow trout immunised with an experimental vaccine based on inactivated V. anguillarum O1 bacterin in Freund's incomplete adjuvant were used for ELISA optimisation. Subsequently, sera from farmed rainbow trout vaccinated with a commercial vaccine against V. anguillarum were analysed with the ELISA. The measured serum antibody levels were compared with the vaccine status of the fish (vaccinated/unvaccinated as evaluated through visual examination. RESULTS: Repeated immunisation with the experimental vaccine lead to increasing levels of specific serum antibodies in the vaccinated rainbow trout. The farmed rainbow trout responded with high antibody levels to a single injection with the commercial vaccine. However, the diversity in responses was more pronounced in the farmed fish. Primary visual examinations for vaccine status in rainbow trout from the commercial farm revealed a large pool of unvaccinated specimens (vaccination failure rate=20% among the otherwise vaccinated fish. Through serum analyses using the ELISA in a blinded set-up it was possible to separate samples collected from the farmed rainbow trout into vaccinated and unvaccinated fish. CONCLUSIONS: Much attention has been devoted to development of new and more effective vaccines. Here we present a case from a Danish rainbow trout farm indicating that attention should also be directed to the vaccination procedure in

  2. Reprodctive biology of trout in a thermally enriched environment: the Firehole River of Yellowstone National Park. Second annual progress report, April 1, 1974--June 30, 1976

    International Nuclear Information System (INIS)

    Temperature recordings indicate that trout inhabiting the warmest section of the river live at temperatures averaging 11.5 C higher than those inhabiting the upstream, cold-water section above most of the thermal discharges. Daily maximum temperatures during summer occasionally exceed published lethal levels for trout, and daily means consistently exceed the 200C upper limit considered favorable for growth. Brown trout at the cold-water station show a normal reproductive pattern and spawn in the late fall. Brown trout at the warmest water station show a similar seasonal pattern; however about half of the specimens examined were either not maturing or were undergoing massive atresia of ova. Rainbow trout also have a similar reproductive pattern and spawn in late fall, in contrast to the normal spring and early summer spawning period of this species. Both species grow considerably faster at the warm-water stations than they do at the cold-water stations, despite having their growth inhibited by high summer temperatures. Differences in diet are evident. Trout captured from both warm and cold areas have internal body temperatures closely similar to water temperatures, and thus provide no evidence for the existence of cooler microhabitats within the general stream

  3. 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.

  4. Single nucleotide polymorphism discovery in cutthroat trout subspecies using genome reduction, barcoding, and 454 pyro-sequencing

    Directory of Open Access Journals (Sweden)

    Houston Derek D

    2012-12-01

    Full Text Available Abstract Background Salmonids are popular sport fishes, and as such have been subjected to widespread stocking throughout western North America. Historically, stocking was done with little regard for genetic variation among populations and has resulted in genetic mixing among species and subspecies in many areas, thus putting the genetic integrity of native salmonid populations at risk and creating a need to assess the genetic constitution of native salmonid populations. Cutthroat trout is a salmonid species with pronounced geographic structure (there are 10 extant subspecies and a recent history of hybridization with introduced rainbow trout in many populations. Genetic admixture has also occurred among cutthroat trout subspecies in areas where introductions have brought two or more subspecies into contact. Consequently, management agencies have increased their efforts to evaluate the genetic composition of cutthroat trout populations to identify populations that remain uncompromised and manage them accordingly, but additional genetic markers are needed to do so effectively. Here we used genome reduction, MID-barcoding, and 454-pyrosequencing to discover single nucleotide polymorphisms that differentiate cutthroat trout subspecies and can be used as a rapid, cost-effective method to characterize the genetic composition of cutthroat trout populations. Results Thirty cutthroat and six rainbow trout individuals were subjected to genome reduction and next-generation sequencing. A total of 1,499,670 reads averaging 379 base pairs in length were generated by 454-pyrosequencing, resulting in 569,060,077 total base pairs sequenced. A total of 43,558 putative SNPs were identified, and of those, 125 SNP primers were developed that successfully amplified 96 cutthroat trout and rainbow trout individuals. These SNP loci were able to differentiate most cutthroat trout subspecies using distance methods and Structure analyses. Conclusions Genomic and

  5. 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.

  6. A STUDY ON TROUT BREEDING IN DUZCE PROVINCE

    OpenAIRE

    Akbulut, Süleyman; KETEN, Akif

    2009-01-01

    In this study, trout breeding facilities of Duzce Province, a suitable place for trout breeding, were evaluated. As a result of this evaluation, current status, capacities, and problems of trout breeding facilities were determined. Some suggestions were provided to solve these problems and increase the capacity of trout breeding facilities. Keywords: Duzce, Trout Breeding.

  7. A nematomorph parasite explains variation in terrestrial subsidies to trout streams in Japan

    Science.gov (United States)

    Sato, Takuya; Watanabe, Katsutoshi; Tokuchi, Naoko; Kamauchi, Hiromitsu; Harada, Yasushi; Lafferty, Kevin D.

    2011-01-01

    Nematomorph parasites alter the behavior of their orthopteran hosts, driving them to water and creating a source of food for stream salmonids. We investigated whether nematomorphs could explain variation in terrestrial subsidies across several streams. In nine study streams, orthopterans comprise much of the stomach contents of trout (46 +/- 31% on average). Total mass of ingested prey per trout biomass positively correlated with the mass of orthopterans ingested, suggesting that the orthopterans enhanced absolute mass of prey consumption by the trout population. The orthopterans ingested per trout biomass positively correlated with the abundance of nematomorphs in the stream, but not with the abundance of camel crickets (the dominant hosts) around the streams. Streams in conifer plantations had fewer nematomorphs than streams in natural deciduous forests. These results provide the first quantitative evidence that a manipulative parasite can explain variation in the allochthonous energy flow through and across ecosystems.

  8. Life+ Trout Project (LIFE12 NAT/IT/0000940 for the recovery and conservation of Mediterranean trout (Salmo trutta complex in the central Apennines (Italy.

    Directory of Open Access Journals (Sweden)

    Vincenzo Caputo Barucchi

    2015-11-01

    At present the genetic and demographic characterization of the trout populations is completed. Table 1 and Figures 1-2 show the results of abundance analysis of the fish assemblages divided by basin. The standing crop’s mean values can be considered in the standard range, according to the small size and the limited productivity that generally characterized the watercourses analyzed, as most of the Apennine rivers. The differences of the mean values among basins were highly statistically significant according to the ANOVA analysis (density: F= 5.24, p=0.001; standing crop: F=12.42, p=0.001. The results of genetic analysis separated clearly native and aliene genomes (K = 2, Fig. 3a and showed the presence of three distinct genetic stocks of native Apennine trout (K = 4, Fig. 3b: i Tevere (green bars, ii Tenna (red and iii Chienti /Potenza/Metauro/Esino (yellow. Populations characterized by very low introgression values will be the source of wild individuals to produce pure juvenile trouts in captivity. Four moderately introgressed populations will be subject to supportive breeding activities. Finally, six stream, where trouts showed almost exclusively an alien genetic make-up will be selected for the eradication activities. The data collected are the indispensable premise for the adoption of the necessary strategies for conservation of the Apennine trout in Central Italy.

  9. 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. 

  10. [Human brown adipose tissue].

    Science.gov (United States)

    Virtanen, Kirsi A; Nuutila, Pirjo

    2015-01-01

    Adult humans have heat-producing and energy-consuming brown adipose tissue in the clavicular region of the neck. There are two types of brown adipose cells, the so-called classic and beige adipose cells. Brown adipose cells produce heat by means of uncoupler protein 1 (UCP1) from fatty acids and sugar. By applying positron emission tomography (PET) measuring the utilization of sugar, the metabolism of brown fat has been shown to multiply in the cold, presumably influencing energy consumption. Active brown fat is most likely present in young adults, persons of normal weight and women, least likely in obese persons.

  11. Atmospheres of Brown Dwarfs

    CERN Document Server

    Helling, Christiane

    2014-01-01

    Brown Dwarfs are the coolest class of stellar objects known to date. Our present perception is that Brown Dwarfs follow the principles of star formation, and that Brown Dwarfs share many characteristics with planets. Being the darkest and lowest mass stars known makes Brown Dwarfs also the coolest stars known. This has profound implication for their spectral fingerprints. Brown Dwarfs cover a range of effective temperatures which cause brown dwarfs atmospheres to be a sequence that gradually changes from a M-dwarf-like spectrum into a planet-like spectrum. This further implies that below an effective temperature of < 2800K, clouds form already in atmospheres of objects marking the boundary between M-Dwarfs and brown dwarfs. Recent developments have sparked the interest in plasma processes in such very cool atmospheres: sporadic and quiescent radio emission has been observed in combination with decaying Xray-activity indicators across the fully convective boundary.

  12. Mexican native trouts: A review of their history and current systematic and conservation status

    Science.gov (United States)

    Hendrickson, D.A.; Perez, H.E.; Findley, L.T.; Forbes, W.; Tomelleri, J.R.; Mayden, Richard L.; Nielsen, J.L.; Jensen, B.; Campos, G.R.; Romero, A.V.; van der Heiden, A.; Camarena, F.; Garcia de Leon, F.J.

    2002-01-01

    While biologists have been aware of the existence of native Mexican trouts for over a century, they have received little study. The few early studies that did much more than mention their existence began in the 1930s and continued into the early 1960s, focusing primarily on distributional surveys and taxonomic analyses. Starting in the 1980s the Baja California rainbow trout became the subject of more detailed studies, but very little remains known of mainland trouts of the Sierra Madre Occidental. We review earlier studies and report on our own collections and observations made between 1975 and 2000. We present newly discovered historical evidence that leads us to conclude that a "lost" cutthroat trout, a lineage not previously known from Mexico, was collected more than a century ago from headwaters of the Ri??o Conchos (a major tributary of the Rio Grande (= Ri??o Bravo)), a basin not previously considered to harbor a native trout. We review the last century of regional natural resource management and discuss our own observations of trout habitats. Impacts of logging, road building and overgrazing are widespread and expanding. Many streams suffer from heavy erosion, siltation and contamination, and though long-term hydrologic data are generally not available, there is evidence of decreased discharge in many streams. These problems appear related to region-wide land management practices as well as recent regional drought. Trout culture operations using exotic rainbow trout have rapidly proliferated throughout the region, threatening genetic introgression and/or competition with native forms and predation on them. Knowledge of distribution, abundance, relationships and taxonomy, not to mention ecology and population biology, of native trouts of the Sierra Madre Occidental remains inadequate. Vast areas of most mainland drainages are still unexplored by fish collectors, and even rudimentary information regarding basic biology, ecology and population structure of

  13. Assessing the impact of swimming exercise and the relative susceptibility of rainbow trout oncorhynchus mykiss (walbaum) and atlantic salmon salmo salar L. following injection challenge with weissella ceti

    Science.gov (United States)

    All-female rainbow trout and mixed-sex Atlantic salmon (approximately 200 g and 120 g initial weight, respectively) were maintained in small circular tanks in a flow-through system under study conditions for a period of five months. The four tank populations consisted of rainbow trout exposed to ei...

  14. 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

  15. Review of potential interactions between stocked rainbow trout and listed Snake River sockeye salmon in Pettit Lake Idaho

    Energy Technology Data Exchange (ETDEWEB)

    Teuscher, D.

    1996-05-01

    The objective of this study was to determine if hatchery rainbow trout compete with or prey on juvenile Snake River sockeye salmon Oncorhynchus nerka in Pettit Lake, Idaho. In 1995, a total of 8,570 age-0 sockeye and 4,000 hatchery rainbow trout were released in Pettit Lake. After releasing the fish, gillnets were set in the pelagic and littoral zones to collected diet and spatial distribution data. Interactions were assessed monthly from June 1995 through March 1996. Competition for food was discounted based on extremely low diet overlap results observed throughout the sample period. Conversely, predation interactions were more significant. A total of 119 rainbow trout stomachs were analyzed, two contained O. nerka. The predation was limited to one sample period, but when extrapolated to the whole rainbow trout populations results in significant losses. Total consumption of O. nerka by rainbow trout ranged from an estimated 10 to 23% of initial stocking numbers. Predation results contradict earlier findings that stocked rainbow trout do not prey on wild kokanee or sockeye in the Sawtooth Lakes. The contradiction may be explained by a combination of poorly adapted hatchery sockeye and a littoral release site that forced spatial overlap that was not occurring in the wild populations. Releasing sockeye in the pelagic zone may have reduced or eliminated predation losses to rainbow trout.

  16. Review of potential interactions between stocked rainbow trout and listed Snake River sockeye salmon in Pettit Lake Idaho

    International Nuclear Information System (INIS)

    The objective of this study was to determine if hatchery rainbow trout compete with or prey on juvenile Snake River sockeye salmon Oncorhynchus nerka in Pettit Lake, Idaho. In 1995, a total of 8,570 age-0 sockeye and 4,000 hatchery rainbow trout were released in Pettit Lake. After releasing the fish, gillnets were set in the pelagic and littoral zones to collected diet and spatial distribution data. Interactions were assessed monthly from June 1995 through March 1996. Competition for food was discounted based on extremely low diet overlap results observed throughout the sample period. Conversely, predation interactions were more significant. A total of 119 rainbow trout stomachs were analyzed, two contained O. nerka. The predation was limited to one sample period, but when extrapolated to the whole rainbow trout populations results in significant losses. Total consumption of O. nerka by rainbow trout ranged from an estimated 10 to 23% of initial stocking numbers. Predation results contradict earlier findings that stocked rainbow trout do not prey on wild kokanee or sockeye in the Sawtooth Lakes. The contradiction may be explained by a combination of poorly adapted hatchery sockeye and a littoral release site that forced spatial overlap that was not occurring in the wild populations. Releasing sockeye in the pelagic zone may have reduced or eliminated predation losses to rainbow trout

  17. Copper uptake across rainbow trout gills: mechanisms of apical entry

    DEFF Research Database (Denmark)

    Grosell, Martin Hautopp; Wood, C. M.

    2002-01-01

    Copper, Homeostasis, sodium uptake, copper/sodium interactions, gill, rainbow trout, Oncorhynchus mykiss......Copper, Homeostasis, sodium uptake, copper/sodium interactions, gill, rainbow trout, Oncorhynchus mykiss...

  18. 不同群体山女鳟及其杂交F1的生产性能比较%Production Performance of Different Populations of Rainbow Trout Oncorhynchus masou masou and Their Cross-breeding F1

    Institute of Scientific and Technical Information of China (English)

    张玉勇; 张永泉; 贾智英; 贾忠贺; 白庆利

    2013-01-01

    本文系统研究了我国引进的两个山女鳟(Oncorhynchus masou masou)群体及其杂交F1代的生产性能.结果表明,(1)两个杂交组合的早期生产性能,如授精率、发眼率和孵化率等不存在显著优势,自交组合BH 08♀×BH08♂的最终成活率为63.37%,远低于其他三组的成活率(P<0.01);(2)378d的生长对比试验表明,杂交组合与自交组合的体质量、绝对增重率、特定生长率和肥满度等存在一定差异,养殖时间对这些指标的影响达到极显著水平(P<0.01),但组间差异仅为显著水平(P<0.05)或没有差异(P>0.05);(3)378d的生长对比试验结束时,两个杂交组合均表现出一定的杂种优势.方差分析表明,不同生长阶段对杂交组合杂种优势率的影响极显著(P<0.01),不同组合间的杂种优势率也存在极显著差异(P<0.01).%In this paper, the production performance were studied in two populations of rainbow trout Oncorhynchus masou masou and their cross-breeding Fl. The results showed that firstly there were no significant differences in production performance including fertil ization, eyed embryonic rate, and hatching success between the cross-breeding F1 (BH 96 9 ♀×BH 08 6 and BH 08 9 ♂ BH 96 5 ) and the controls (BH 96 ♀× BH 96 6 and BH 08 9 × BH 08 5 (P>0.05), with survival rate of only 63.3% in BH 08 9 ♀× BH 08 ♂ , very significantly lower than in the others (P0.05 ).Thirdly after a 378-day experi ment the cross-breeding Fl appeared some growth heterosis. The analysis of variance showed that the heterosis difference was affected not only by culture-time, but also among different groups (P<0.01).

  19. Characterization of brown adipose tissue ¹⁸F-FDG uptake in PET/CT imaging and its influencing factors in the Chinese population.

    Science.gov (United States)

    Shao, Xiaonan; Shao, Xiaoliang; Wang, Xiaosong; Wang, Yuetao

    2016-01-01

    (18)F-FDG PET/CT has been widely applied for tumor imaging. However, it is reported that many normal tissues, e.g., brown adipose tissue, can also uptake (18)F-FDG. The purpose of this study was to determine the imaging characteristics of (18)F-FDG uptake in brown adipose tissue (BAT) in PET/CT. A total of 2,944 patients who underwent PET/CT from September 2011 to March 2013 were analyzed retrospectively. Imaging features of (18)F-FDG uptake in BAT were analyzed. Univariate analysis and logistic regression analysis were performed to evaluate the effect of age, gender, cancer status, body mass index (BMI), average daily maximum temperature of imaging month and fasting plasma glucose (Glu) on the positive rate of (18)F-FDG uptake in BAT. The results showed that 1.9% (57/2944) patients had (18)F-FDG uptake in BAT. (18)F-FDG, manifested as flaky, nodular and beaded shape, was symmetrically distributed in the adipose tissues of cervical and supraclavicular, mediastinal, paravertebral, and perirenal areas. Uptake of (18)F-FDG within cervical/supraclavicular area was most common (89.5%, 51/57) with an SUVmax ranging from 2.8 to 31.4. Univariate analysis showed that gender and cancer status were not significantly correlated with the BAT (18)F-FDG uptake rate. In contrast, age, BMI, Glu and average daily maximum temperature in the imaging month were significantly correlated with the BAT (18)F-FDG uptake rate (Puptake rate was age, followed by the average daily maximum temperature and BMI. We concluded that Chinese adult has low positive rate of (18)F-FDG uptake in BAT. Cervical/Supraclavicular is the most common area with BAT (18)F-FDG uptake. Age, average daily maximum temperature and BMI are independent factors affecting (18)F-FDG uptake. PMID:26702781

  20. 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.

  1. 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.

  2. Study of Some Morphological Characters of Three Trout Breed Farmed in Salmonid Exploitations from Moldova

    Directory of Open Access Journals (Sweden)

    Cătălin Emilian Nistor

    2014-05-01

    Full Text Available Study of morphological characters at fish by means of biometry is a frequently utilized method and consists in determining the variability of characters in groups of individuals, by direct measurement, weighting and statistical processing of obtained data.Effectuation of body measurements and weighting is used to determine the increase in length of fish and to evaluate the general physiological condition. Brook trout, rainbow trout, and brown trout were the object of the current study by analyzing of 50 individuals, 10 individuals in each batch (F1, F2, C1 C2 and I1, from two trout farms from Moldova. After processing the obtained data were calculated the most representative indexes and maintenance coefficients. The obtained values were between 3.49 at batch F1 and 3.94 at batch I1 for profile index; 1.5 at batch I1 and 1.75 at batch F1 for Fulton coefficient; 1.47 at batch F2 and 1.6 at batch I1 for Kiselev index; 41.36 for batch F1 and 47.94 at batch C2 for thickness index; 19.94 C1 batch and 22.08 at F1 batch for fleshy index I, and 19.05 C2 batch and 21.2 at I1 batch for fleshy index II. Having in view the obtained results we can conclude that the analyzed fishes had a good state of maintenance.

  3. Brown Fat Cell Isolation

    OpenAIRE

    sprotocols

    2014-01-01

    Author: C.R. Kahn ### 1.) ISOLATION AND PRIMARY CULTURE OF BROWN FAT PREADIPOCYTES ### Rationale: To prepare primary brown preadipocytes for immortalization: useful for metabolic studies from knockout mice. This consists of the following five protocols. References: Fasshauer, M., J. Klein, K M. Kriauciunas, K. Ueki, M.Benito, and C.R. Kahn. 2001. Essential role of insulin substrate 1 in differentiation of brown adipocytes. *Mol Cell Biol* 21: 319-329. Fasshauer, M....

  4. Status and conservation of interior Redband Trout in the western United States

    Science.gov (United States)

    Muhlfeld, Clint C.; Albeke, Shannon E.; Gunckel, Stephanie L; Writer, Benjamin J; Shepard, Bradley B.; May, Bruce E

    2015-01-01

    In this article we describe the current status and conservation of interior (potamodromous) Redband Trout Oncorhynchus mykiss sspp. throughout its range in the western United States using extant data and expert opinion provided by fish managers. Redband Trout historically occupied 60,295 km of stream habitat and 152 natural lakes. Currently, Redband Trout occupy 25,417 km of stream habitat (42% of their historical range) and 124 lakes or reservoirs. Nonhybridized populations are assumed to occupy 11,695 km (46%) of currently occupied streams; however, fish from only 4,473 km (18%) have been genetically tested. Approximately 47% of the streams occupied by Redband Trout occur on private land, 45% on government lands, and 8% in protected areas. A total of 210 Redband Trout populations, occupying 15,252 km of stream habitat (60% of the current distribution) and 95,158 ha of lake habitat (52%), are being managed as “conservation populations.” Most conservation populations have been designated as weakly to strongly connected metapopulations (125; 60%) and occupy much more stream length (14,112 km; 93%) than isolated conservation populations (1,141 km; 7%). The primary threats to Redband Trout include invasive species, habitat degradation and fragmentation, and climate change. Although the historical distribution of interior Redband Trout has declined dramatically, we conclude that the species is not currently at imminent risk of extinction because it is still widely distributed with many populations isolated by physical barriers and active conservation efforts are occurring for many populations. However, the hybridization status of many populations has not been well quantified, and introgression may be more prevalent than documented here. We recommend (1) collecting additional genetic data and estimating distribution and abundance by means of a more rigorous spatial sampling design to reduce uncertainties, (2) collecting additional information to assess and

  5. Giant planet and brown dwarf formation

    CERN Document Server

    Chabrier, G; Janson, M; Rafikov, R

    2014-01-01

    Understanding the dominant brown dwarf and giant planet formation processes, and finding out whether these processes rely on completely different mechanisms or share common channels represents one of the major challenges of astronomy and remains the subject of heated debates. It is the aim of this review to summarize the latest developments in this field and to address the issue of origin by confronting different brown dwarf and giant planet formation scenarios to presently available observational constraints. As examined in the review, if objects are classified as "Brown Dwarfs" or "Giant Planets" on the basis of their formation mechanism, it has now become clear that their mass domains overlap and that there is no mass limit between these two distinct populations. Furthermore, while there is increasing observational evidence for the existence of non-deuterium burning brown dwarfs, some giant planets, characterized by a significantly metal enriched composition, might be massive enough to ignite deuterium bur...

  6. Improved husbandry to control an outbreak of rainbow trout fry syndrome caused by infection with Flavobacterium psychrophilum

    Science.gov (United States)

    Bebak, J.A.; Welch, T.J.; Starliper, C.E.; Baya, A.M.; Garner, M.M.

    2007-01-01

    Case Description - A cohort of 35,200, 13-week-old, female rainbow trout at a fish farm was evaluated because of a 2-week history of anorexia and lethargy and a mortality rate of approximately 100 fish/d. Clinical Findings - Affected fish were lethargic and thin and had disequilibrium, bilateral exophthalmia, pale red gills and kidneys, red-tinged coelomic fluid, and pale brown livers. Some fish were differentially pigmented bilaterally. The presumptive diagnosis was bacterial or viral septicemia. The definitive diagnosis was rainbow trout fry syndrome caused by infection with Flavobacterium psychrophilum. Treatment and Outcome - A strategy for controlling the outbreak based on reducing pathogen numbers in affected tanks and reducing pathogen spread among tanks was developed. The option of treating with antimicrobial-medicated feed was discussed with the farmer, but was declined. After changes were made, mortality rate declined quickly, with no more deaths within 10 days after the initial farm visit. Clinical Relevance - Bacterial coldwater disease is the most common manifestation of infection with F psychrophilum in fingerling and adult rainbow trout. However, the organism can also cause rainbow trout fry syndrome. This condition should be included on a list of differential diagnoses for septicemia in hatchery-reared rainbow trout fry.

  7. 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

  8. Characterization of brown adipose tissue ¹⁸F-FDG uptake in PET/CT imaging and its influencing factors in the Chinese population.

    Science.gov (United States)

    Shao, Xiaonan; Shao, Xiaoliang; Wang, Xiaosong; Wang, Yuetao

    2016-01-01

    (18)F-FDG PET/CT has been widely applied for tumor imaging. However, it is reported that many normal tissues, e.g., brown adipose tissue, can also uptake (18)F-FDG. The purpose of this study was to determine the imaging characteristics of (18)F-FDG uptake in brown adipose tissue (BAT) in PET/CT. A total of 2,944 patients who underwent PET/CT from September 2011 to March 2013 were analyzed retrospectively. Imaging features of (18)F-FDG uptake in BAT were analyzed. Univariate analysis and logistic regression analysis were performed to evaluate the effect of age, gender, cancer status, body mass index (BMI), average daily maximum temperature of imaging month and fasting plasma glucose (Glu) on the positive rate of (18)F-FDG uptake in BAT. The results showed that 1.9% (57/2944) patients had (18)F-FDG uptake in BAT. (18)F-FDG, manifested as flaky, nodular and beaded shape, was symmetrically distributed in the adipose tissues of cervical and supraclavicular, mediastinal, paravertebral, and perirenal areas. Uptake of (18)F-FDG within cervical/supraclavicular area was most common (89.5%, 51/57) with an SUVmax ranging from 2.8 to 31.4. Univariate analysis showed that gender and cancer status were not significantly correlated with the BAT (18)F-FDG uptake rate. In contrast, age, BMI, Glu and average daily maximum temperature in the imaging month were significantly correlated with the BAT (18)F-FDG uptake rate (P<0.05). Further logistic regression analysis showed that only age, BMI and average daily maximum temperature were significant (OR<1, P<0.05). Based on the value of OR, the most significant factor that affects BAT (18)F-FDG uptake rate was age, followed by the average daily maximum temperature and BMI. We concluded that Chinese adult has low positive rate of (18)F-FDG uptake in BAT. Cervical/Supraclavicular is the most common area with BAT (18)F-FDG uptake. Age, average daily maximum temperature and BMI are independent factors affecting (18)F-FDG uptake.

  9. Father Brown, Selected sories

    NARCIS (Netherlands)

    Chesterton, G.K.

    2005-01-01

    Father Brown, a small, round Catholic priest with a remarkable understanding of the criminal mind, is one of literature's most unusual and endearing detectives, able to solve the strangest crimes in a most fascinating manner. This collection draws from all five Father Brown books, and within their r

  10. Seasonal and spatial patterns of growth of rainbow trout in the Colorado River in Grand Canyon, AZ

    Science.gov (United States)

    Yard, Micheal D.; Korman, Josh; Walters, Carl J.; Kennedy, T.A.

    2016-01-01

    Rainbow trout (Oncorhynchus mykiss) have been purposely introduced in many regulated rivers, with inadvertent consequences on native fishes. We describe how trout growth rates and condition could be influencing trout population dynamics in a 130 km section of the Colorado River below Glen Canyon Dam based on a large-scale mark–recapture program where ∼8000 rainbow trout were recaptured over a 3-year period (2012–2014). There were strong temporal and spatial variations in growth in both length and weight as predicted from von Bertalanffy and bioenergetic models, respectively. There was more evidence for seasonal variation in the growth coefficient and annual variation in the asymptotic length. Bioenergetic models showed more variability for growth in weight across seasons and years than across reaches. These patterns were consistent with strong seasonal variation in invertebrate drift and effects of turbidity on foraging efficiency. Highest growth rates and relative condition occurred in downstream reaches with lower trout densities. Results indicate that reduction in rainbow trout abundance in Glen Canyon will likely increase trout size in the tailwater fishery and may reduce downstream dispersal into Grand Canyon.

  11. Temporary Restoration of Bull Trout Passage at Albeni Falls Dam

    Energy Technology Data Exchange (ETDEWEB)

    Paluch, Mark; Scholz, Allan; McLellan, Holly [Eastern Washington University Department of Biology; Olson, Jason [Kalispel Tribe of Indians Natural Resources Department

    2009-07-13

    This study was designed to monitor movements of bull trout that were provided passage above Albeni Falls Dam, Pend Oreille River. Electrofishing and angling were used to collect bull trout below the dam. Tissue samples were collected from each bull trout and sent to the U. S. Fish and Wildlife Service Abernathy Fish Technology Center Conservation Genetics Lab, Washington. The DNA extracted from tissue samples were compared to a catalog of bull trout population DNA from the Priest River drainage, Lake Pend Oreille tributaries, and the Clark Fork drainage to determine the most probable tributary of origin. A combined acoustic radio or radio tag was implanted in each fish prior to being transported and released above the dam. Bull trout relocated above the dam were able to volitionally migrate into their natal tributary, drop back downstream, or migrate upstream to the next dam. A combination of stationary radio receiving stations and tracking via aircraft, boat, and vehicle were used to monitor the movement of tagged fish to determine if the spawning tributary it selected matched the tributary assigned from the genetic analysis. Seven bull trout were captured during electrofishing surveys in 2008. Of these seven, four were tagged and relocated above the dam. Two were tagged and left below the dam as part of a study monitoring movements below the dam. One was immature and too small at the time of capture to implant a tracking tag. All four fish released above the dam passed by stationary receivers stations leading into Lake Pend Oreille and no fish dropped back below the dam. One of the radio tags was recovered in the tributary corresponding with the results of the genetic test. Another fish was located in the vicinity of its assigned tributary, which was impassable due to low water discharge at its mouth. Two fish have not been located since entering the lake. Of these fish, one was immature and not expected to enter its natal tributary in the fall of 2008. The other

  12. Lice pressure from salmon farms on wild sea trout (Salmo trutta in a Norwegian fjord

    Directory of Open Access Journals (Sweden)

    Pablo Arechavala-Lopez

    2015-11-01

    Full Text Available Salmon lice Lepeophtheirus salmonis are external parasites on salmonids in the marine environment. However, during recent years, salmon lice abundance has increased due to the presence of salmon farming. Scientific studies shows that salmon farming increases the abundance of lice in the marine habitat and that salmon lice in the most intensively farmed areas have negatively affected wild fish populations. The present study assesses the spatiotemporal distribution of salmon lice infestations on wild sea trout population in the Romsdalsfjord region (Norway, and the potential relationship with fish-farming activity and environmental parameters in this area. Salmon lice at farms varied among localities or farming areas, although infestation levels were under the safety established thresholds (max: 0.5 adult females per fish in most of the cases. However, salmon farms with these levels might produce and release millions of copepods, potentially infecting wild salmonids. In accordance, low lice loads were recorded on wild sea trout captured in areas with low farming activity, while higher mean loads were recorded in areas with higher farming activity. A clear seasonal pattern and a positive correlation between lice on sea trout and sea water temperature were observed throughout the study period. The estimated production of copepods at farms and the mobile lice counted on wild sea trout one month later were correlated, suggesting the potential use of lice monitoring on sea trout as a proxy indicator of salmon lice infestation risks.

  13. Impact of climatic factors to the percentage of young in the population of brown hare (Lepus europaeus P in the Bačka district

    Directory of Open Access Journals (Sweden)

    Beuković Miloš

    2013-01-01

    Full Text Available Climatic factors, especially temperature and precipitations, greatly affect the dynamics of the hare number and population. Climatic factors directly affect the physiological and reproductive processes of both individuals and entire populations, or indirectly, through the availability of food, competition with other species, predators and other. The age structure of the hare population at the end of the period of reproduction is an important indicator of the population growth that is used for planning the level of explotation of the hare population (hunting. The rational use of the hare's population is one of the most important protection procedures and it should be well monitored and controlled by the hunting professionals. We used the average monthly temperature and the sum of monthly precipitations in the hare reproductive period (March-September during ten years (2000 - 2009, together with the percent of young in the hare population, on the territory of Bačka, for multiple regression (stepwise analysis. Results of the regression analysis show an association between the percentage of young hares and the influence of climatic factors. The average temperature and sum of precipitation in June, are the strongest predictor of the percent of young in the hare’s population in Bačka. According to the coefficient of determination (R2=0.50 climatic parameters account for 50% of variance in the percentage of young hares in Bačka. The regression correlation coefficient of all factors was R=0.70, which is on the border line between medium and high correlation.

  14. Rainbow Trout Innate Immunity against Flavobacterium psychrophilum

    Science.gov (United States)

    Flavobacterium psychrophilum infection is associated with significant loss of rainbow trout production in the U.S. and other parts of the world. In 2005, a selective breeding program was initiated at the National Center for Cool and Cold Water Aquaculture to improve rainbow trout innate resistance ...

  15. Farming of Freshwater Rainbow Trout in Denmark

    DEFF Research Database (Denmark)

    Jokumsen, Alfred; Svendsen, Lars Moeslund

    Textbook on Farming of Freshwater Rainbow Trout in Denmark. Danish edition with the title: Opdræt af regnbueørred i Danmark......Textbook on Farming of Freshwater Rainbow Trout in Denmark. Danish edition with the title: Opdræt af regnbueørred i Danmark...

  16. 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.

  17. Variability in seroprevalence of rabies virus neutralizing antibodies and associated factors in a Colorado population of big brown bats (Eptesicus fuscus)

    Science.gov (United States)

    O’Shea, Thomas J.; Bowen, Richard A.; Stanley, Thomas R.; Shankar, Vidya; Rupprecht, Charles E.

    2014-01-01

    In 2001–2005 we sampled permanently marked big brown bats (Eptesicus fuscus) at summer roosts in buildings at Fort Collins, Colorado, for rabies virus neutralizing antibodies (RVNA). Seroprevalence was higher in adult females (17.9%, n = 2,332) than males (9.4%, n = 128; P = 0.007) or volant juveniles (10.2%, n = 738; Pbats. Seroprevalence also increased with age of bat, and varied from 6.2 to 26.7% among adult females at five roosts sampled each year for five years. Seroprevalence of adult females at 17 other roosts sampled for 1 to 4 years ranged from 0.0 to 47.1%. Using logistic regression, the only ranking model in our candidate set of explanatory variables for serological status at first sampling included year, day of season, and a year by day of season interaction that varied with relative drought conditions. The presence or absence of antibodies in individual bats showed temporal variability. Year alone provided the best model to explain the likelihood of adult female bats showing a transition to seronegative from a previously seropositive state. Day of the season was the only competitive model to explain the likelihood of a transition from seronegative to seropositive, which increased as the season progressed. We found no rabies viral RNA in oropharyngeal secretions of 261 seropositive bats or in organs of 13 euthanized seropositive bats. Survival of seropositive and seronegative bats did not differ. The presence of RVNA in serum of bats should not be interpreted as evidence for ongoing rabies infection.

  18. Wigwam River juvenile bull trout and fish habitat monitoring program : 2001 data report

    International Nuclear Information System (INIS)

    The Wigwam River juvenile bull trout and fish habitat monitoring program is a co-operative initiative of the British Columbia Ministry of Water, Land, and Air Protection and Bonneville Power Administration. The Wigwam River has been characterized as the single most important bull trout spawning stream in the Kootenay Region. This report provides a summary of results obtained during the second year (2001) of the juvenile bull trout enumeration and fish habitat assessment program. This project was commissioned in planning for fish habitat protection and forest development within the upper Wigwam River valley. The broad intent is to develop a better understanding of juvenile bull trout and Westslope cutthroat trout recruitment and the ongoing hydrologic and morphologic processes in the upper Wigwam River, especially as they relate to spawning and rearing habitat quality. Five permanent sampling sites were established August 2000 in the Wigwam river drainage (one site on Bighorn Creek and four sites on the mainstem Wigwam River). At each site, juvenile (0(sup+), 1(sup+) and 2(sup+) age classes) fish densities and stream habitat conditions were measured over two stream meander wavelengths. Bull trout represented 95.1% of the catch and the mean density of juvenile bull trout was estimated to be 20.7 fish/100m(sup 2) (range 0.9 to 24.0 fish/100m(sup 2)). This compares to 17.2 fish/100m(sup 2) (+20%) for the previous year. Fry (0(sup+)) dominated the catch and this was a direct result of juvenile bull trout ecology and habitat partitioning among life history stages. Site selection was biased towards sample sites which favored high bull trout fry capture success. Comparison of fry density estimates replicated across both the preliminary survey (1997) and the current study (Cope and Morris 2001) illustrate the stable nature of these high densities. Bull trout populations have been shown to be extremely susceptible to habitat degradation and over-harvest and are ecologically

  19. Bath vaccination of rainbow trout against yersiniosis

    DEFF Research Database (Denmark)

    Raida, Martin Kristian; Buchmann, Kurt

    2007-01-01

    Studies have been conducted on the temperature-dependent effect of bath vaccination of rainbow trout against Yersinia ruckeri O1. Protection of rainbow trout fry against challenge, following bath vaccination with a bacterin of Yersinia ruckeri O1, the bacterial pathogen causing enteric red mouth...... disease (ERM), was investigated at 5, 15 and 25° C. Rainbow trout fry were kept at controlled temperatures for two month before they were immersed in a commercial Yersinia ruckeri O1 bacterin for 10 minutes. Control groups were sham vaccinated using pure water. Fish were challenged with Yersinia ruckeri O......1 one and two month post vaccination at the three temperatures. Protection of vaccinated fish was seen one and two month post vaccination in rainbow trout reared at 15° C. There was no effect of vaccination in rainbow trout reared at 5 and 25° C. Spleen tissue was sampled from 5 vaccinated and 5...

  20. A second generation genetic map for rainbow trout (Oncorhynchus mykiss

    Directory of Open Access Journals (Sweden)

    Gahr Scott A

    2008-11-01

    Full Text Available Abstract Background Genetic maps characterizing the inheritance patterns of traits and markers have been developed for a wide range of species and used to study questions in biomedicine, agriculture, ecology and evolutionary biology. The status of rainbow trout genetic maps has progressed significantly over the last decade due to interest in this species in aquaculture and sport fisheries, and as a model research organism for studies related to carcinogenesis, toxicology, comparative immunology, disease ecology, physiology and nutrition. We constructed a second generation genetic map for rainbow trout using microsatellite markers to facilitate the identification of quantitative trait loci for traits affecting aquaculture production efficiency and the extraction of comparative information from the genome sequences of model fish species. Results A genetic map ordering 1124 microsatellite loci spanning a sex-averaged distance of 2927.10 cM (Kosambi and having 2.6 cM resolution was constructed by genotyping 10 parents and 150 offspring from the National Center for Cool and Cold Water Aquaculture (NCCCWA reference family mapping panel. Microsatellite markers, representing pairs of loci resulting from an evolutionarily recent whole genome duplication event, identified 180 duplicated regions within the rainbow trout genome. Microsatellites associated with genes through expressed sequence tags or bacterial artificial chromosomes produced comparative assignments with tetraodon, zebrafish, fugu, and medaka resulting in assignments of homology for 199 loci. Conclusion The second generation NCCCWA genetic map provides an increased microsatellite marker density and quantifies differences in recombination rate between the sexes in outbred populations. It has the potential to integrate with cytogenetic and other physical maps, identifying paralogous regions of the rainbow trout genome arising from the evolutionarily recent genome duplication event, and

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Genomic evidence of geographically widespread effect of gene flow from polar bears into brown bears

    OpenAIRE

    Cahill, J.; Stirling, I.; Kistler, L.; Salamzade, R.; Ersmark, E.; Fulton, T.; Stiller, M.; Green, R.; Shapiro, B.

    2015-01-01

    Polar bears are an arctic, marine adapted species that is closely related to brown bears. Genome analyses have shown that polar bears are distinct and genetically homogeneous in comparison to brown bears. However, these analyses have also revealed a remarkable episode of polar bear gene flow into the population of brown bears that colonized the Admiralty, Baranof and Chichagof islands (ABC islands) of Alaska. Here, we present an analysis of data from a large panel of polar bear and brown bear...

  7. A Management Strategy for Kenai Peninsula Brown Bears

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Increasing human activity and land development on the Kenai Peninsula, Alaska has brought about concern for the brown bear (Ursus arctos) population. The human...

  8. Movement patterns, habitat use, and survival of Lahontan cutthroat trout in the Truckee River

    Science.gov (United States)

    Alexiades, Alexander V.; Peacock, Mary M.; Al-Chokhachy, Robert K.

    2012-01-01

    Habitat fragmentation, hybridization, and competition with nonnative salmonids are viewed as major threats to Lahontan cutthroat trout Oncorhynchus clarkii henshawi. Understanding Lahontan cutthroat trout behavior and survival is a necessary step in the reintroduction and establishment of naturally reproducing populations of Lahontan cutthroat trout. We used weekly radiotelemetry monitoring to examine movement patterns, habitat use, and apparent survival of 42 hatchery-reared Lahontan cutthroat trout in a 16.5-km stretch of the Truckee River, Nevada, across three reaches separated by barriers to upstream movement. We found differences in total movement distances and home range sizes of fish in different reaches within our study area. Fish used pool habitats more than fast water habitats in all reaches. Time of year, stream temperature, and fish standard length covariates had the strongest relationship with apparent survival. Monthly apparent survival was lowest in January, which coincided with the lowest flows and temperatures during the study period. Our results verify the mobility of Lahontan cutthroat trout and indicate that conditions during winter may limit the survival and reintroduction success in the portions of the Truckee River evaluated in this study.

  9. Patterns of hybridization among cutthroat trout and rainbow trout in northern Rocky Mountain streams

    OpenAIRE

    McKelvey, Kevin S.; Young, Michael K.; Taylor M Wilcox; Bingham, Daniel M.; Pilgrim, Kristine L.; Schwartz, Michael K.

    2016-01-01

    Abstract Introgressive hybridization between native and introduced species is a growing conservation concern. For native cutthroat trout and introduced rainbow trout in western North America, this process is thought to lead to the formation of hybrid swarms and the loss of monophyletic evolutionary lineages. Previous studies of this phenomenon, however, indicated that hybrid swarms were rare except when native and introduced forms of cutthroat trout co‐occurred. We used a panel of 86 diagnost...

  10. Spatial behaviour and survival of translocated wild brown hares

    OpenAIRE

    Fischer, C.; TAGAND, R.

    2012-01-01

    The fragility of many populations of brown hares in Western Europe is a concern for managers, hunters and naturalists. We took advantage of a locally high density population to use wild individuals to restock areas where the species had disappeared or was close to disappearing. The aim of the project was to assess the evolution of the spatial behaviour after release using radio–tracking. Over 150 wild brown hares were translocated, one third of which were fitted with radio collars. In additio...

  11. Who’s your mama? Riverine hybridisation of threatened freshwater Trout Cod and Murray Cod

    Science.gov (United States)

    Unmack, Peter J.; Dyer, Fiona J.; Lintermans, Mark

    2016-01-01

    Rates of hybridization and introgression are increasing dramatically worldwide because of translocations, restocking of organisms and habitat modifications; thus, determining whether hybridization is occuring after reintroducing extirpated congeneric species is commensurately important for conservation. Restocking programs are sometimes criticized because of the genetic consequences of hatchery-bred fish breeding with wild populations. These concerns are important to conservation restocking programs, including those from the Australian freshwater fish family, Percichthyidae. Two of the better known Australian Percichthyidae are the Murray Cod, Maccullochella peelii and Trout Cod, Maccullochella macquariensis which were formerly widespread over the Murray Darling Basin. In much of the Murrumbidgee River, Trout Cod and Murray Cod were sympatric until the late 1970s when Trout Cod were extirpated. Here we use genetic single nucleotide polymorphism (SNP) data together with mitochondrial sequences to examine hybridization and introgression between Murray Cod and Trout Cod in the upper Murrumbidgee River and consider implications for restocking programs. We have confirmed restocked riverine Trout Cod reproducing, but only as inter-specific matings, in the wild. We detected hybrid Trout Cod–Murray Cod in the Upper Murrumbidgee, recording the first hybrid larvae in the wild. Although hybrid larvae, juveniles and adults have been recorded in hatcheries and impoundments, and hybrid adults have been recorded in rivers previously, this is the first time fertile F1 have been recorded in a wild riverine population. The F1 backcrosses with Murray cod have also been found to be fertile. All backcrosses noted were with pure Murray Cod. Such introgression has not been recorded previously in these two species, and the imbalance in hybridization direction may have important implications for restocking programs.

  12. Multiscale Genetic Structure of Yellowstone Cutthroat Trout in the Upper Snake River Basin.

    Energy Technology Data Exchange (ETDEWEB)

    Cegelski, Christine C.; Campbell, Matthew R.

    2006-05-30

    Populations of Yellowstone cutthroat trout Oncorhynchus clarkii bouvierii have declined throughout their native range as a result of habitat fragmentation, overharvest, and introductions of nonnative trout that have hybridized with or displaced native populations. The degree to which these factors have impacted the current genetic population structure of Yellowstone cutthroat trout populations is of primary interest for their conservation. In this study, we examined the genetic diversity and genetic population structure of Yellowstone cutthroat trout in Idaho and Nevada with data from six polymorphic microsatellite loci. A total of 1,392 samples were analyzed from 45 sample locations throughout 11 major river drainages. We found that levels of genetic diversity and genetic differentiation varied extensively. The Salt River drainage, which is representative of the least impacted migration corridors in Idaho, had the highest levels of genetic diversity and low levels of genetic differentiation. High levels of genetic differentiation were observed at similar or smaller geographic scales in the Portneuf River, Raft River, and Teton River drainages, which are more altered by anthropogenic disturbances. Results suggested that Yellowstone cutthroat trout are naturally structured at the major river drainage level but that habitat fragmentation has altered this structuring. Connectivity should be restored via habitat restoration whenever possible to minimize losses in genetic diversity and to preserve historical processes of gene flow, life history variation, and metapopulation dynamics. However, alternative strategies for management and conservation should also be considered in areas where there is a strong likelihood of nonnative invasions or extensive habitat fragmentation that cannot be easily ameliorated.

  13. Genetically Based Location from Triploid Populations and Gene Ontology of a 3.3-Mb Genome Region Linked to Alternaria Brown Spot Resistance in Citrus Reveal Clusters of Resistance Genes

    Science.gov (United States)

    Cuenca, José; Aleza, Pablo; Vicent, Antonio; Brunel, Dominique; Ollitrault, Patrick; Navarro, Luis

    2013-01-01

    Genetic analysis of phenotypical traits and marker-trait association in polyploid species is generally considered as a challenge. In the present work, different approaches were combined taking advantage of the particular genetic structures of 2n gametes resulting from second division restitution (SDR) to map a genome region linked to Alternaria brown spot (ABS) resistance in triploid citrus progeny. ABS in citrus is a serious disease caused by the tangerine pathotype of the fungus Alternaria alternata. This pathogen produces ACT-toxin, which induces necrotic lesions on fruit and young leaves, defoliation and fruit drop in susceptible genotypes. It is a strong concern for triploid breeding programs aiming to produce seedless mandarin cultivars. The monolocus dominant inheritance of susceptibility, proposed on the basis of diploid population studies, was corroborated in triploid progeny. Bulk segregant analysis coupled with genome scan using a large set of genetically mapped SNP markers and targeted genetic mapping by half tetrad analysis, using SSR and SNP markers, allowed locating a 3.3 Mb genomic region linked to ABS resistance near the centromere of chromosome III. Clusters of resistance genes were identified by gene ontology analysis of this genomic region. Some of these genes are good candidates to control the dominant susceptibility to the ACT-toxin. SSR and SNP markers were developed for efficient early marker-assisted selection of ABS resistant hybrids. PMID:24116149

  14. Genetically based location from triploid populations and gene ontology of a 3.3-mb genome region linked to Alternaria brown spot resistance in citrus reveal clusters of resistance genes.

    Directory of Open Access Journals (Sweden)

    José Cuenca

    Full Text Available Genetic analysis of phenotypical traits and marker-trait association in polyploid species is generally considered as a challenge. In the present work, different approaches were combined taking advantage of the particular genetic structures of 2n gametes resulting from second division restitution (SDR to map a genome region linked to Alternaria brown spot (ABS resistance in triploid citrus progeny. ABS in citrus is a serious disease caused by the tangerine pathotype of the fungus Alternaria alternata. This pathogen produces ACT-toxin, which induces necrotic lesions on fruit and young leaves, defoliation and fruit drop in susceptible genotypes. It is a strong concern for triploid breeding programs aiming to produce seedless mandarin cultivars. The monolocus dominant inheritance of susceptibility, proposed on the basis of diploid population studies, was corroborated in triploid progeny. Bulk segregant analysis coupled with genome scan using a large set of genetically mapped SNP markers and targeted genetic mapping by half tetrad analysis, using SSR and SNP markers, allowed locating a 3.3 Mb genomic region linked to ABS resistance near the centromere of chromosome III. Clusters of resistance genes were identified by gene ontology analysis of this genomic region. Some of these genes are good candidates to control the dominant susceptibility to the ACT-toxin. SSR and SNP markers were developed for efficient early marker-assisted selection of ABS resistant hybrids.

  15. Genetically based location from triploid populations and gene ontology of a 3.3-mb genome region linked to Alternaria brown spot resistance in citrus reveal clusters of resistance genes.

    Science.gov (United States)

    Cuenca, José; Aleza, Pablo; Vicent, Antonio; Brunel, Dominique; Ollitrault, Patrick; Navarro, Luis

    2013-01-01

    Genetic analysis of phenotypical traits and marker-trait association in polyploid species is generally considered as a challenge. In the present work, different approaches were combined taking advantage of the particular genetic structures of 2n gametes resulting from second division restitution (SDR) to map a genome region linked to Alternaria brown spot (ABS) resistance in triploid citrus progeny. ABS