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Sample records for salmon disrupt trophic

  1. Spawning salmon disrupt trophic coupling between wolves and ungulate prey in coastal British Columbia

    Directory of Open Access Journals (Sweden)

    Darimont Chris T

    2008-09-01

    Full Text Available Abstract Background As a cross-boundary resource subsidy, spawning salmon can strongly affect consumer and ecosystem ecology. Here we examine whether this marine resource can influence a terrestrial wolf-deer (Canis lupus-Odocoileus hemionus predator-prey system in coastal British Columbia, Canada. Data on resource availability and resource use among eight wolf groups for three seasons over four years allow us to evaluate competing hypotheses that describe salmon as either an alternate resource, consumed in areas where deer are scarce, or as a targeted resource, consumed as a positive function of its availability. Faecal (n = 2203 wolf scats and isotopic analyses (n = 60 wolf hair samples provide independent data sets, also allowing us to examine how consistent these common techniques are in estimating foraging behaviour. Results At the population level during spring and summer, deer remains occurred in roughly 90 and 95% of faeces respectively. When salmon become available in autumn, however, the population showed a pronounced dietary shift in which deer consumption among groups was negatively correlated (r = -0.77, P 13C isotopic signatures (r = 0.78; P = 0.008, which were calculated by intra-hair comparisons between segments grown during summer and fall. The magnitude of this seasonal isotopic shift, our proxy for salmon use, was related primarily to estimates of salmon availability, not deer availability, among wolf groups. Conclusion Concordance of faecal and isotopic data suggests our intra-hair isotopic methodology provides an accurate proxy for salmon consumption, and might reliably track seasonal dietary shifts in other consumer-resource systems. Use of salmon by wolves as a function of its abundance and the adaptive explanations we provide suggest a long-term and widespread association between wolves and salmon. Seasonally, this system departs from the common wolf-ungulate model. Broad ecological implications include the potential

  2. Spawning salmon disrupt trophic coupling between wolves and ungulate prey in coastal British Columbia.

    Science.gov (United States)

    Darimont, Chris T; Paquet, Paul C; Reimchen, Thomas E

    2008-09-02

    As a cross-boundary resource subsidy, spawning salmon can strongly affect consumer and ecosystem ecology. Here we examine whether this marine resource can influence a terrestrial wolf-deer (Canis lupus-Odocoileus hemionus) predator-prey system in coastal British Columbia, Canada. Data on resource availability and resource use among eight wolf groups for three seasons over four years allow us to evaluate competing hypotheses that describe salmon as either an alternate resource, consumed in areas where deer are scarce, or as a targeted resource, consumed as a positive function of its availability. Faecal (n=2203 wolf scats) and isotopic analyses (n=60 wolf hair samples) provide independent data sets, also allowing us to examine how consistent these common techniques are in estimating foraging behaviour. At the population level during spring and summer, deer remains occurred in roughly 90 and 95% of faeces respectively. When salmon become available in autumn, however, the population showed a pronounced dietary shift in which deer consumption among groups was negatively correlated (r=-0.77, Ppopulation dynamics, and the distribution of salmon nutrients by wolves into coastal ecosystems.

  3. Warming Ocean Conditions Relate to Increased Trophic Requirements of Threatened and Endangered Salmon.

    Science.gov (United States)

    Daly, Elizabeth A; Brodeur, Richard D

    2015-01-01

    The trophic habits, size and condition of yearling Chinook salmon (Oncorhynchus tshawytscha) caught early in their marine residence were examined during 19 survey years (1981-1985; 1998-2011). Juvenile salmon consumed distinct highly piscivorous diets in cold and warm ocean regimes with major differences between ocean regimes driven by changes in consumption of juvenile rockfishes, followed by several other fish prey, adult euphausiids and decapod larvae. Notable, Chinook salmon consumed 30% more food in the warm versus cold ocean regime in both May and June. Additionally, there were about 30% fewer empty stomachs in the warm ocean regime in May, and 10% fewer in warm June periods. The total prey energy density consumed during the warmer ocean regime was also significantly higher than in cold. Chinook salmon had lower condition factor and were smaller in fork length during the warm ocean regime, and were longer and heavier for their size during the cold ocean regime. The significant increase in foraging during the warm ocean regime occurred concurrently with lower available prey biomass. Adult return rates of juvenile Chinook salmon that entered the ocean during a warm ocean regime were lower. Notably, our long term data set contradicts the long held assertion that juvenile salmon eat less in a warm ocean regime when low growth and survival is observed, and when available prey are reduced. Comparing diet changes between decades under variable ocean conditions may assist us in understanding the effects of projected warming ocean regimes on juvenile Chinook salmon and their survival in the ocean environment. Bioenergetically, the salmon appear to require more food resources during warm ocean regimes.

  4. Trophic ontogeny of fluvial Bull Trout and seasonal predation on Pacific Salmon in a riverine food web

    Science.gov (United States)

    Lowery, Erin D.; Beauchamp, David A.

    2015-01-01

    Bull Trout Salvelinus confluentus are typically top predators in their host ecosystems. The Skagit River in northwestern Washington State contains Bull Trout and Chinook Salmon Oncorhynchus tshawytschapopulations that are among the largest in the Puget Sound region and also contains a regionally large population of steelhead O. mykiss (anadromous Rainbow Trout). All three species are listed as threatened under the Endangered Species Act (ESA). Our objective was to determine the trophic ecology of Bull Trout, especially their role as predators and consumers in the riverine food web. We seasonally sampled distribution, diets, and growth of Bull Trout in main-stem and tributary habitats during 2007 and winter–spring 2008. Consumption rates were estimated with a bioenergetics model to (1) determine the annual and seasonal contributions of different prey types to Bull Trout energy budgets and (2) estimate the potential impacts of Bull Trout predation on juvenile Pacific salmon populations. Salmon carcasses and eggs contributed approximately 50% of the annual energy budget for large Bull Trout in main-stem habitats, whereas those prey types were largely inaccessible to smaller Bull Trout in tributary habitats. The remaining 50% of the energy budget was acquired by eating juvenile salmon, resident fishes, and immature aquatic insects. Predation on listed Chinook Salmon and steelhead/Rainbow Trout was highest during winter and spring (January–June). Predation on juvenile salmon differed between the two study years, likely due to the dominant odd-year spawning cycle for Pink Salmon O. gorbuscha. The population impact on ocean- and stream-type Chinook Salmon was negligible, whereas the impact on steelhead/Rainbow Trout was potentially very high. Due to the ESA-listed status of Bull Trout, steelhead, and Chinook Salmon, the complex trophic interactions in this drainage provide both challenges and opportunities for creative adaptive management strategies.

  5. Disruption of Trophic Inhibitory Signaling in Autism Sepctrum Disorders

    Science.gov (United States)

    2016-12-01

    responses. This switch is known to be delayed in several neurodevelopmental disorders including Fragile X Syndrome , some forms of syndromic and non...Fragile X mouse model. We found: 1) that EGABA development was not disrupted in the mouse model of Angelman Syndrome 2) EGABA development was delayed in...bumetanide to mice rescues synaptic and circuit dysfunction in Fragile X mice. 15. SUBJECT TERMS Autism Spectrum Disorders, Fragile X Syndrome Angelman

  6. Trophic pathways supporting juvenile Chinook and Coho salmon in the glacial Susitna River, Alaska: patterns of freshwater, marine, and terrestrial resource use across a seasonally dynamic habitat mosaic

    Science.gov (United States)

    Rine, Kristin M.; Wipfli, Mark S.; Schoen, Erik R.; Nightengale, Timothy L.; Stricker, Craig A.

    2016-01-01

    Contributions of terrestrial-, freshwater-, and marine-derived prey resources to stream fishes vary over time and space, altering the energy pathways that regulate production. In this study, we determined large-scale use of these resources by juvenile Chinook and coho salmon (Oncorhynchus tshawytscha and Oncorhynchus kisutch, respectively) in the glacial Susitna River, Alaska. We resolved spatial and temporal trophic patterns among multiple macrohabitat types along a 97 km segment of the river corridor via stable isotope and stomach content analyses. Juvenile salmon were supported primarily by freshwater-derived resources and secondarily by marine and terrestrial sources. The relative contribution of marine-derived prey to rearing salmon was greatest in the fall within off-channel macrohabitats, whereas the contributions of terrestrial invertebrate prey were generally greatest during midsummer, across all macrohabitats. No longitudinal (upstream–downstream) diet pattern was discernable. These results highlight large-scale spatial and seasonal patterns of energy flow and the dynamic interplay of pulsed marine and terrestrial prey subsidies to juvenile Chinook and coho salmon in a large, complex, and relatively pristine glacial river.

  7. Comparative responses to endocrine disrupting compounds in early life stages of Atlantic salmon, Salmo salar

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    Duffy, Tara A.; Iwanowicz, Luke R.; McCormick, Stephen D.

    2014-01-01

    Atlantic salmon (Salmo salar) are endangered anadromous fish that may be exposed to feminizing endocrine disrupting compounds (EDCs) during early development, potentially altering physiological capacities, survival and fitness. To assess differential life stage sensitivity to common EDCs, we carried out short-term (four day) exposures using three doses each of 17α-ethinylestradiol (EE2), 17β-estradiol (E2), and nonylphenol (NP) on four early life stages; embryos, yolk-sac larvae, feeding fry and one year old smolts. Differential response was compared using vitellogenin (Vtg, a precursor egg protein) gene transcription. Smolts were also examined for impacts on plasma Vtg, cortisol, thyroid hormones (T4/T3) and hepatosomatic index (HSI). Compound-related mortality was not observed in any life stage, but Vtg mRNA was elevated in a dose-dependent manner in yolk-sac larvae, fry and smolts but not in embyos. The estrogens EE2 and E2 were consistently stronger inducers of Vtg than NP. Embryos responded significantly to the highest concentration of EE2 only, while older life stages responded to the highest doses of all three compounds, as well as intermediate doses of EE2 and E2. Maximal transcription was greater for fry among the three earliest life stages, suggesting fry may be the most responsive life stage in early development. Smolt plasma Vtg was also significantly increased, and this response was observed at lower doses of each compound than was detected by gene transcription suggesting this is a more sensitive indicator at this life stage. HSI was increased at the highest doses of EE2 and E2 and plasma T3 decreased at the highest dose of EE2. Our results indicate that all life stages after hatching are potentially sensitive to endocrine disruption by estrogenic compounds and that physiological responses were altered over a short window of exposure, indicating the potential for these compounds to impact fish in the wild.

  8. Trophic interactions and consumption rates of subyearling Chinook Salmon and nonnative juvenile American Shad in Columbia River reservoirs

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    Haskell, Craig A.; Beauchamp, David A.; Bollins, Stephen M

    2017-01-01

    We used a large lampara seine coupled with nonlethal gastric lavage to examine the diets and estimate consumption rates of subyearling Chinook Salmon Oncorhynchus tshawytscha during July and August 2013. During August we also examined the diet and consumption rates of juvenile American Shad Alosa sapidissima, a potential competitor of subyearling Chinook Salmon. Subyearling Chinook Salmon consumed Daphnia in July but switched to feeding on smaller juvenile American Shad in August. We captured no juvenile American Shad in July, but in August juvenile American Shad consumed cyclopoid and calanoid copepods. Stomach evacuation rates for subyearling Chinook Salmon were high during both sample periods (0.58 h−1 in July, 0.51 h−1 in August), and daily ration estimates were slightly higher than values reported in the literature for other subyearlings. By switching from planktivory to piscivory, subyearling Chinook Salmon gained greater growth opportunity. While past studies have shown that juvenile American Shad reduce zooplankton availability for Chinook Salmon subyearlings, our work indicates that they also become important prey after Daphnia abundance declines. The diet and consumption data here can be used in future bioenergetics modeling to estimate the growth of subyearling Chinook Salmon in lower Columbia River reservoirs.

  9. Trophic disruption: a meta-analysis of how habitat fragmentation affects resource consumption in terrestrial arthropod systems.

    Science.gov (United States)

    Martinson, Holly M; Fagan, William F

    2014-09-01

    Habitat fragmentation is a complex process that affects ecological systems in diverse ways, altering everything from population persistence to ecosystem function. Despite widespread recognition that habitat fragmentation can influence food web interactions, consensus on the factors underlying variation in the impacts of fragmentation across systems remains elusive. In this study, we conduct a systematic review and meta-analysis to quantify the effects of habitat fragmentation and spatial habitat structure on resource consumption in terrestrial arthropod food webs. Across 419 studies, we found a negative overall effect of fragmentation on resource consumption. Variation in effect size was extensive but predictable. Specifically, resource consumption was reduced on small, isolated habitat fragments, higher at patch edges, and neutral with respect to landscape-scale spatial variables. In general, resource consumption increased in fragmented settings for habitat generalist consumers but decreased for specialist consumers. Our study demonstrates widespread disruption of trophic interactions in fragmented habitats and describes variation among studies that is largely predictable based on the ecological traits of the interacting species. We highlight future prospects for understanding how changes in spatial habitat structure may influence trophic modules and food webs. © 2014 John Wiley & Sons Ltd/CNRS.

  10. Invasive European bird cherry disrupts stream-riparian linkages: effects on terrestrial invertebrate prey subsidies for juvenile coho salmon

    Science.gov (United States)

    Roon, David A.; Wipfli, Mark S.; Wurtz, Tricia L.; Blanchard, Arny L.

    2016-01-01

    The spread of invasive species in riparian forests has the potential to affect both terrestrial and aquatic organisms linked through cross-ecosystem resource subsidies. However, this potential had not been explored in regards to terrestrial prey subsidies for stream fishes. To address this, we examined the effects of an invasive riparian tree, European bird cherry (EBC, Prunus padus), spreading along urban Alaskan salmon streams, by collecting terrestrial invertebrates present on the foliage of riparian trees, their subsidies to streams, and their consumption by juvenile coho salmon (Oncorhynchus kisutch). Riparian EBC supported four to six times less terrestrial invertebrate biomass on its foliage and contributed two to three times lower subsidies relative to native deciduous trees. This reduction in terrestrial invertebrate biomass was consistent between two watersheds over 2 years. In spite of this reduction in terrestrial prey resource input, juvenile coho salmon consumed similar levels of terrestrial invertebrates in stream reaches bordered by EBC. Although we did not see ecological effects extending to stream salmonids, reduced terrestrial prey subsidies to streams are likely to have negative consequences as EBC continues to spread.

  11. SALMON 2100: THE FUTURE OF WILD PACIFIC SALMON

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    Many experts have concluded that wild salmon recovery efforts in western North America (especially California, Oregon, Washington, Idaho, and southern British Columbia), as earnest, expensive, and socially disruptive as they currently are, do not appear likely to sustain biologic...

  12. Organic salmon

    DEFF Research Database (Denmark)

    Ankamah Yeboah, Isaac; Nielsen, Max; Nielsen, Rasmus

    The year 2016 is groundbreaking for organic aquaculture producers in EU, as it represents the deadline for implementing a full organic life cycle in the aquaculture production. Such a shift induces production costs for farmers and if it should be profitable, they must receive higher prices....... This study identifies the price premium on organic salmon in the Danish retail sale sector using consumer panel scanner data for households by applying the hedonic price model while permitting unobserved heterogeneity between households. A premium of 20% for organic salmon is found. Since this premium...... is closer to organic labeled agriculture products than to ecolabelled capture fisheries products, it indicates that consumers value organic salmon as an agriculture product more than fisheries product....

  13. The trophic groups in Coleoptera

    OpenAIRE

    Marinoni, Renato C.

    2001-01-01

    The beetles are a useful group for studies on trophic structure of communities, mainly in forested areas. These kind of studies are based on food habits of species groups. The different terms applied to nomminated these groups (trophic category, ecologic group, trophic group, guild, trophic guild) are discussed. The term trophic group, a natural unity, is proposed to form a group of species with the same food habits, not considering the trophic level. The guild, an artificial unity, is recogn...

  14. Green Turtle Trophic Ecology

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — SWFSC is currently conducting a study of green sea turtle (Chelonia mydas) trophic ecology in the eastern Pacific. Tissue samples and stable carbon and stable...

  15. Impacts of intensive logging on the trophic organisation of ant communities in a biodiversity hotspot.

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    Woodcock, Paul; Edwards, David P; Newton, Rob J; Vun Khen, Chey; Bottrell, Simon H; Hamer, Keith C

    2013-01-01

    Trophic organisation defines the flow of energy through ecosystems and is a key component of community structure. Widespread and intensifying anthropogenic disturbance threatens to disrupt trophic organisation by altering species composition and relative abundances and by driving shifts in the trophic ecology of species that persist in disturbed ecosystems. We examined how intensive disturbance caused by selective logging affects trophic organisation in the biodiversity hotspot of Sabah, Borneo. Using stable nitrogen isotopes, we quantified the positions in the food web of 159 leaf-litter ant species in unlogged and logged rainforest and tested four predictions: (i) there is a negative relationship between the trophic position of a species in unlogged forest and its change in abundance following logging, (ii) the trophic positions of species are altered by logging, (iii) disturbance alters the frequency distribution of trophic positions within the ant assemblage, and (iv) disturbance reduces food chain length. We found that ant abundance was 30% lower in logged forest than in unlogged forest but changes in abundance of individual species were not related to trophic position, providing no support for prediction (i). However, trophic positions of individual species were significantly higher in logged forest, supporting prediction (ii). Consequently, the frequency distribution of trophic positions differed significantly between unlogged and logged forest, supporting prediction (iii), and food chains were 0.2 trophic levels longer in logged forest, the opposite of prediction (iv). Our results demonstrate that disturbance can alter trophic organisation even without trophically-biased changes in community composition. Nonetheless, the absence of any reduction in food chain length in logged forest suggests that species-rich arthropod food webs do not experience trophic downgrading or a related collapse in trophic organisation despite the disturbance caused by logging

  16. Impacts of intensive logging on the trophic organisation of ant communities in a biodiversity hotspot.

    Directory of Open Access Journals (Sweden)

    Paul Woodcock

    Full Text Available Trophic organisation defines the flow of energy through ecosystems and is a key component of community structure. Widespread and intensifying anthropogenic disturbance threatens to disrupt trophic organisation by altering species composition and relative abundances and by driving shifts in the trophic ecology of species that persist in disturbed ecosystems. We examined how intensive disturbance caused by selective logging affects trophic organisation in the biodiversity hotspot of Sabah, Borneo. Using stable nitrogen isotopes, we quantified the positions in the food web of 159 leaf-litter ant species in unlogged and logged rainforest and tested four predictions: (i there is a negative relationship between the trophic position of a species in unlogged forest and its change in abundance following logging, (ii the trophic positions of species are altered by logging, (iii disturbance alters the frequency distribution of trophic positions within the ant assemblage, and (iv disturbance reduces food chain length. We found that ant abundance was 30% lower in logged forest than in unlogged forest but changes in abundance of individual species were not related to trophic position, providing no support for prediction (i. However, trophic positions of individual species were significantly higher in logged forest, supporting prediction (ii. Consequently, the frequency distribution of trophic positions differed significantly between unlogged and logged forest, supporting prediction (iii, and food chains were 0.2 trophic levels longer in logged forest, the opposite of prediction (iv. Our results demonstrate that disturbance can alter trophic organisation even without trophically-biased changes in community composition. Nonetheless, the absence of any reduction in food chain length in logged forest suggests that species-rich arthropod food webs do not experience trophic downgrading or a related collapse in trophic organisation despite the disturbance caused by

  17. Howling about Trophic Cascades

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    Kowalewski, David

    2012-01-01

    Following evolutionary theory and an agriculture model, ecosystem research has stressed bottom-up dynamics, implying that top wild predators are epiphenomenal effects of more basic causes. As such, they are assumed expendable. A more modern co-evolutionary and wilderness approach--trophic cascades--instead suggests that top predators, whose…

  18. Climate and ecosystem linkages explain widespread declines in North American Atlantic salmon populations.

    Science.gov (United States)

    Mills, Katherine E; Pershing, Andrew J; Sheehan, Timothy F; Mountain, David

    2013-10-01

    North American Atlantic salmon (Salmo salar) populations experienced substantial declines in the early 1990s, and many populations have persisted at low abundances in recent years. Abundance and productivity declined in a coherent manner across major regions of North America, and this coherence points toward a potential shift in marine survivorship, rather than local, river-specific factors. The major declines in Atlantic salmon populations occurred against a backdrop of physical and biological shifts in Northwest Atlantic ecosystems. Analyses of changes in climate, physical, and lower trophic level biological factors provide substantial evidence that climate conditions directly and indirectly influence the abundance and productivity of North American Atlantic salmon populations. A major decline in salmon abundance after 1990 was preceded by a series of changes across multiple levels of the ecosystem, and a subsequent population change in 1997, primarily related to salmon productivity, followed an unusually low NAO event. Pairwise correlations further demonstrate that climate and physical conditions are associated with changes in plankton communities and prey availability, which are ultimately linked to Atlantic salmon populations. Results suggest that poor trophic conditions, likely due to climate-driven environmental factors, and warmer ocean temperatures throughout their marine habitat area are constraining the productivity and recovery of North American Atlantic salmon populations. © 2013 John Wiley & Sons Ltd.

  19. Salmon-derived nitrogen in terrestrial invertebrates from coniferous forests of the Pacific Northwest.

    Science.gov (United States)

    Hocking, Morgan D; Reimchen, Thomas E

    2002-03-19

    Bi-directional flow of nutrients between marine and terrestrial ecosystems can provide essential resources that structure communities in transitional habitats. On the Pacific coast of North America, anadromous salmon (Oncorhynchus spp.) constitute a dominant nutrient subsidy to aquatic habitats and riparian vegetation, although the contribution to terrestrial habitats is not well established. We use a dual isotope approach of delta15N and delta13C to test for the contribution of salmon nutrients to multiple trophic levels of litter-based terrestrial invertebrates below and above waterfalls that act as a barrier to salmon migration on two watersheds in coastal British Columbia. Invertebrates varied predictably in delta15N with enrichment of 3-8 per thousand below the falls compared with above the falls in all trophic groups on both watersheds. We observed increasing delta15N levels in our invertebrate groups with increasing consumption of dietary protein. Invertebrates varied in delta13C but did not always vary predictably with trophic level or habitat. From 19.4 to 71.5% of invertebrate total nitrogen was originally derived from salmon depending on taxa, watershed, and degree of fractionation from the source. Enrichment of delta15N in the invertebrate community below the falls in conjunction with the absence of delta13C enrichment suggests that enrichment in delta15N occurs primarily through salmon-derived nitrogen subsidies to litter, soil and vegetation N pools rather than from direct consumption of salmon tissue or salmon tissue consumers. Salmon nutrient subsidies to terrestrial habitats may result in shifts in invertebrate community structure, with subsequent implications for higher vertebrate consumers, particularly the passerines.

  20. Salmon-derived nitrogen in terrestrial invertebrates from coniferous forests of the Pacific Northwest

    Directory of Open Access Journals (Sweden)

    Reimchen Thomas E

    2002-03-01

    Full Text Available Abstract Background Bi-directional flow of nutrients between marine and terrestrial ecosystems can provide essential resources that structure communities in transitional habitats. On the Pacific coast of North America, anadromous salmon (Oncorhynchus spp. constitute a dominant nutrient subsidy to aquatic habitats and riparian vegetation, although the contribution to terrestrial habitats is not well established. We use a dual isotope approach of δ15N and δ13C to test for the contribution of salmon nutrients to multiple trophic levels of litter-based terrestrial invertebrates below and above waterfalls that act as a barrier to salmon migration on two watersheds in coastal British Columbia. Results Invertebrates varied predictably in δ15N with enrichment of 3–8‰ below the falls compared with above the falls in all trophic groups on both watersheds. We observed increasing δ15N levels in our invertebrate groups with increasing consumption of dietary protein. Invertebrates varied in δ13C but did not always vary predictably with trophic level or habitat. From 19.4 to 71.5% of invertebrate total nitrogen was originally derived from salmon depending on taxa, watershed, and degree of fractionation from the source. Conclusions Enrichment of δ15N in the invertebrate community below the falls in conjunction with the absence of δ13C enrichment suggests that enrichment in δ15N occurs primarily through salmon-derived nitrogen subsidies to litter, soil and vegetation N pools rather than from direct consumption of salmon tissue or salmon tissue consumers. Salmon nutrient subsidies to terrestrial habitats may result in shifts in invertebrate community structure, with subsequent implications for higher vertebrate consumers, particularly the passerines.

  1. Response of nutrients, biofilm, and benthic insects to salmon carcass addition.

    Science.gov (United States)

    Shannon M. Claeson; Judith L. Li; Jana E. Compton; Peter A. Bisson

    2006-01-01

    Salmon carcass addition to streams is expected to increase stream productivity at multiple trophic levels. This study examined stream nutrient (nitrogen, phosphorus, and carbon), epilithic biofilm (ash-free dry mass and chlorophyll a), leaf-litter decomposition, and macroinvertebrate (density and biomass) responses to carcass addition in three headwater streams of...

  2. Trophic strategies of unicellular plankton

    DEFF Research Database (Denmark)

    Chakraborty, Subhendu; Nielsen, Lasse Tor; Andersen, Ken Haste

    2017-01-01

    Unicellular plankton employ trophic strategies ranging from pure photoautotrophs over mixotrophy to obligate heterotrophs (phagotrophs), with cell sizes from 10-8 to 1 μg C. A full understanding of how trophic strategy and cell size depend on resource environment and predation is lacking. To this......Unicellular plankton employ trophic strategies ranging from pure photoautotrophs over mixotrophy to obligate heterotrophs (phagotrophs), with cell sizes from 10-8 to 1 μg C. A full understanding of how trophic strategy and cell size depend on resource environment and predation is lacking...... unicellulars are colimited by organic carbon and nutrients, and only large photoautotrophs and smaller mixotrophs are nutrient limited; (2) trophic strategy is bottom-up selected by the environment, while optimal size is top-down selected by predation. The focus on cell size and trophic strategies facilitates...

  3. MULTICRITERIA BAYESIAN ANALYSIS OF LOWER TROPHIC LEVEL UNCERTAINTIES AND VALUE OF RESEARCH IN LAKE ERIE. (R825150)

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    Human activities have severely disrupted the Lake Erie ecosystem. Recent changes in the structure of the lower trophic level associated with exotic species invasions and reduced nutrient loading have created ecological uncertainties for fisheries management. Decisions that na&...

  4. Atlantic Salmon Smolt Monitoring

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Annual data are collected as part of smolt trapping operations using fish trapping methods. Traps collect emigrating salmon smolts to identify cohort...

  5. Atlantic Salmon Telemetry Monitoring

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    National Oceanic and Atmospheric Administration, Department of Commerce — Annual telemetry data are collected as part of specific projects (assessments within watersheds) or as opportunistic efforts to characterize Atlantic salmon smolt...

  6. Calcitonin Salmon Nasal Spray

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    ... bottle and turn to tighten. Then take the plastic cover off of the top of the spray unit. ... room temperature in an upright position. Replace the plastic cover to keep the nozzle clean. Opened calcitonin salmon ...

  7. INFECTIOUS SALMON ANEMIA

    Directory of Open Access Journals (Sweden)

    M. Yu. Shchelkanov

    2017-01-01

    Full Text Available The aim of this work consists in the analysis of modern scientific conceptions about infectious salmon anemia (ISA etiologically linked with ISAV (infectious salmon anemia virus (Orthomyxoviridae, Isavirus. ISA is deadly disease of Salmonidae fishes.Discussion. ISA began to extend actively among salmon breeding farms since the extremity of the XX century and poses nowadays serious threat of fishing industry as there are no not only anti-ISAV chemopreparates and effective vaccines, but also scientifically based ideas of ISAV ecology. In the offered review data on the discovery history, taxonomical status, virion morphology and genome structure as well as ecology of ISAV, clinical features, pathogenesis and laboratory diagnostics, actions in the epizootic foci for the prevention of further distribution and prophylaxis of ISA, arrangement for protection against salmon louses and utilized approaches to anti-ISAV vaccines development are discussed. There is very important that ISAV is capable to be transferred by salmon louses – pelagic crustaceans (Copepoda: Caligidae that allows to classify ISAV as arbovirus ecological group which are transferred due to biological transmission by arthropods (copepods to vertebrate animals (salmons. It is the only example known so far when representatives of Crustacea act as a vector for arboviruses.Conclusion. Investigation of ISAV ecology turns into one of "touchstones" allowing to judge technological readiness of mankind to master resources of the World Ocean. 

  8. Salmon 2100: the future of wild Pacific salmon

    National Research Council Canada - National Science Library

    Lackey, R.T; Lach, D.H; Duncan, S.L

    2006-01-01

    Realistic options to restore and sustain wild salmon runs in California, Oregon, Washington, Idaho and southern British Columbia are identified by 36 salmon scientists, resource managers, and policy experts...

  9. Salmon lice – impact on wild salmonids and salmon aquaculture

    Science.gov (United States)

    Torrissen, O; Jones, S; Asche, F; Guttormsen, A; Skilbrei, O T; Nilsen, F; Horsberg, T E; Jackson, D

    2013-01-01

    Salmon lice, Lepeophtheirus salmonis, are naturally occurring parasites of salmon in sea water. Intensive salmon farming provides better conditions for parasite growth and transmission compared with natural conditions, creating problems for both the salmon farming industry and, under certain conditions, wild salmonids. Salmon lice originating from farms negatively impact wild stocks of salmonids, although the extent of the impact is a matter of debate. Estimates from Ireland and Norway indicate an odds ratio of 1.1:1-1.2:1 for sea lice treated Atlantic salmon smolt to survive sea migration compared to untreated smolts. This is considered to have a moderate population regulatory effect. The development of resistance against drugs most commonly used to treat salmon lice is a serious concern for both wild and farmed fish. Several large initiatives have been taken to encourage the development of new strategies, such as vaccines and novel drugs, for the treatment or removal of salmon lice from farmed fish. The newly sequenced salmon louse genome will be an important tool in this work. The use of cleaner fish has emerged as a robust method for controlling salmon lice, and aquaculture production of wrasse is important towards this aim. Salmon lice have large economic consequences for the salmon industry, both as direct costs for the prevention and treatment, but also indirectly through negative public opinion. PMID:23311858

  10. Pacific Coastal Salmon Recovery Fund

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Congress established the Pacific Coastal Salmon Recovery Fund (PCSRF) to monitor the restoration and conservation of Pacific salmon and steelhead populations and...

  11. Identifying salmon lice transmission characteristics between Faroese salmon farms

    DEFF Research Database (Denmark)

    Kragesteen, Trondur J.; Simonsen, Knud; Visser, AW

    2017-01-01

    Sea lice infestations are an increasing challenge in the ever-growing salmon aquaculture sector and cause large economic losses. The high salmon production in a small area creates a perfect habitat for parasites. Knowledge of how salmon lice planktonic larvae disperse and spread the infection...... between farms is of vital importance in developing treatment management plans to combat salmon lice infestations. Using a particle tracking model forced by tidal currents, we show that Faroese aquaculture farms form a complex network. In some cases as high as 10% of infectious salmon lice released at one...

  12. Prey partitioning and use of insects by juvenile sockeye salmon and a potential competitor, threespine stickleback, in Afognak Lake, Alaska

    Science.gov (United States)

    Richardson, Natura; Beaudreau, Anne H.; Wipfli, Mark S.; Finkle, Heather

    2017-01-01

    Freshwater growth of juvenile sockeye salmon (Oncorhynchus nerka) depends upon the quality and quantity of prey and interactions with potential competitors in the foraging environment. To a large extent, knowledge about the ecology of lake-rearing juvenile sockeye salmon has emerged from studies of commercially important runs returning to deep nursery lakes, yet information from shallow nursery lakes (mean depth ≤ 10 m) is limited. We examined seasonal and ontogenetic variation in diets of juvenile sockeye salmon (N = 219, 30–85 mm) and an abundant potential competitor, threespine stickleback (Gasterosteus aculeatus; N = 198, 42–67 mm), to understand their foraging ecology and potential trophic interactions in a shallow Alaska lake. This study revealed that adult insects made up 74% of all sockeye salmon diets by weight and were present in 98% of all stomachs in Afognak Lake during the summer of 2013. Diets varied temporally for all fishes, but small sockeye salmon (insects in late summer. We found significant differences in diet composition between sockeye salmon and threespine stickleback and the origin of their prey indicated that they also separated their use of habitat on a fine scale; however, the two species showed overlap in size selectivity of zooplankton prey. Considering that aquatic insects can be a primary resource for juvenile sockeye salmon in Afognak Lake, we encourage the development of nursery lake carrying capacity models that include aquatic insects as a prey source for sockeye salmon.

  13. Physiological consequences of the salmon louse (Lepeophtheirus salmonis) on juvenile pink salmon (Oncorhynchus gorbuscha): implications for wild salmon ecology and management, and for salmon aquaculture.

    Science.gov (United States)

    Brauner, C J; Sackville, M; Gallagher, Z; Tang, S; Nendick, L; Farrell, A P

    2012-06-19

    Pink salmon, Oncorhynchus gorbuscha, are the most abundant wild salmon species and are thought of as an indicator of ecosystem health. The salmon louse, Lepeophtheirus salmonis, is endemic to pink salmon habitat but these ectoparasites have been implicated in reducing local pink salmon populations in the Broughton Archipelago, British Columbia. This allegation arose largely because juvenile pink salmon migrate past commercial open net salmon farms, which are known to incubate the salmon louse. Juvenile pink salmon are thought to be especially sensitive to this ectoparasite because they enter the sea at such a small size (approx. 0.2 g). Here, we describe how 'no effect' thresholds for salmon louse sublethal impacts on juvenile pink salmon were determined using physiological principles. These data were accepted by environmental managers and are being used to minimize the impact of salmon aquaculture on wild pink salmon populations.

  14. Disruptive firms

    OpenAIRE

    Coccia, Mario

    2017-01-01

    This study proposes the concept of disruptive firms: they are firms with market leadership that deliberate introduce new and improved generations of durable goods that destroy, directly or indirectly, similar products present in markets in order to support their competitive advantage and/or market leadership. These disruptive firms support technological and industrial change and induce consumers to buy new products to adapt to new socioeconomic environment. In particular, disruptive firms gen...

  15. The decline of the trophic level concept.

    Science.gov (United States)

    Cousins, S

    1987-10-01

    The development of the trophic level concept(1) is described and the causes of its failure as a predictive model in ecology are examined. A defence(2) of and modifications to the trophic level concept are reviewed. A trend towards taxonomic food web analysis is identified leading to models that are independent of the trophic level approach. Copyright © 1987. Published by Elsevier Ltd.

  16. Digital Disruption

    DEFF Research Database (Denmark)

    Rosenstand, Claus Andreas Foss

    det digitale domæne ud over det niveau, der kendetegner den nuværende debat, så præsenteres der ny viden om digital disruption. Som noget nyt udlægges Clayton Christens teori om disruptiv innovation med et særligt fokus på små organisationers mulighed for eksponentiel vækst. Specielt udfoldes...... forholdet mellem disruption og den stadig accelererende digitale udvikling i konturerne til ny teoridannelse om digital disruption. Bogens undertitel ”faretruende og fascinerende forandringer” peger på, at der er behov for en nuanceret debat om digital disruption i modsætning til den tone, der er slået an i...... videre kalder et ”disruption-råd”. Faktisk er rådet skrevet ind i 2016 regeringsgrundlaget for VLK-regeringen. Disruption af organisationer er ikke et nyt fænomen; men hastigheden, hvormed det sker, er stadig accelererende. Årsagen er den globale mega-trend: Digitalisering. Og derfor er specielt digital...

  17. Relative resistance of Pacific salmon to infectious salmon anaemia virus.

    Science.gov (United States)

    Rolland, J B; Winton, J R

    2003-09-01

    Infectious salmon anaemia (ISA) is a major disease of Atlantic salmon, Salmo salar, caused by an orthomyxovirus (ISAV). Increases in global aquaculture and the international movement of fish made it important to determine if Pacific salmon are at risk. Steelhead trout, Oncorhynchus mykiss, and chum, O. keta, Chinook, O. tshawytscha, coho, O. kisutch, and Atlantic salmon were injected intraperitoneally with a high, medium, or low dose of a Norwegian strain of ISAV. In a second challenge, the same species, except chum salmon, were injected with a high dose of either a Canadian or the Norwegian strain. Average cumulative mortality of Atlantic salmon in trial 1 was 12% in the high dose group, 20% in the medium dose group and 16% in the low dose group. The average cumulative mortality of Atlantic salmon in trial 2 was 98%. No signs typical of ISA and no ISAV-related mortality occurred among any of the groups of Oncorhynchus spp. in either experiment, although ISAV was reisolated from some fish sampled at intervals post-challenge. The results indicate that while Oncorhynchus spp. are quite resistant to ISAV relative to Atlantic salmon, the potential for ISAV to adapt to Oncorhynchus spp. should not be ignored.

  18. A time-lapse photography method for monitoring salmon (Oncorhynchus spp. passage and abundance in streams

    Directory of Open Access Journals (Sweden)

    William W. Deacy

    2016-06-01

    Full Text Available Accurately estimating population sizes is often a critical component of fisheries research and management. Although there is a growing appreciation of the importance of small-scale salmon population dynamics to the stability of salmon stock-complexes, our understanding of these populations is constrained by a lack of efficient and cost-effective monitoring tools for streams. Weirs are expensive, labor intensive, and can disrupt natural fish movements. While conventional video systems avoid some of these shortcomings, they are expensive and require excessive amounts of labor to review footage for data collection. Here, we present a novel method for quantifying salmon in small streams (<15 m wide, <1 m deep that uses both time-lapse photography and video in a model-based double sampling scheme. This method produces an escapement estimate nearly as accurate as a video-only approach, but with substantially less labor, money, and effort. It requires servicing only every 14 days, detects salmon 24 h/day, is inexpensive, and produces escapement estimates with confidence intervals. In addition to escapement estimation, we present a method for estimating in-stream salmon abundance across time, data needed by researchers interested in predator--prey interactions or nutrient subsidies. We combined daily salmon passage estimates with stream specific estimates of daily mortality developed using previously published data. To demonstrate proof of concept for these methods, we present results from two streams in southwest Kodiak Island, Alaska in which high densities of sockeye salmon spawn.

  19. Infectious diseases of Pacific salmon

    Science.gov (United States)

    1954-01-01

    Investigations on infectious diseases of Pacific salmon due to micro-organisms other than viruses are reviewed. The etiological agents include trematodes, fungi, protozoa and bacteria. Bacteria have been found to be the most important agents of disease in the several species of Pacific salmon. Kidney disease, due to a small, unnamed Gram-positive diplobacillus, causes serious mortalities in young salmon reared in hatcheries. The disease has also been found in wild fish. Aquatic myxobacteria are important agents of disease both in the hatchery and in the natural habitat. One of the myxobacteria, Chondrococcus columnaris, causes disease at relatively high water temperatures. The problem of the taxonomy of this organism is discussed. Another myxobacterium, Cytophaga psychrophila, has been found responsible for epizootics in coho salmon at lower water temperatures, i.e., in the range of 40° to 55° F. In outbreaks of gill disease in young salmon, myxobacteria of several kinds have been implicated.

  20. Disrupting Business

    DEFF Research Database (Denmark)

    Cox, Geoff; Bazzichelli, Tatiana

    Disruptive Business explores some of the interconnections between art, activism and the business concept of disruptive innovation. With a backdrop of the crisis of financial capitalism, austerity cuts in the cultural sphere, the idea is to focus on potential art strategies in relation to a broken...... economy. In a perverse way, we ask whether this presents new opportunities for cultural producers to achieve more autonomy over their production process. If it is indeed possible, or desirable, what alternative business models emerge? The book is concerned broadly with business as material for reinvention...

  1. Environmental conditions and prey-switching by a seabird predator impact juvenile salmon survival

    Science.gov (United States)

    Wells, Brian K.; Santora, Jarrod A.; Henderson, Mark J.; Warzybok, Pete; Jahncke, Jaime; Bradley, Russell W.; Huff, David D.; Schroeder, Isaac D.; Nelson, Peter; Field, John C.; Ainley, David G.

    2017-01-01

    Due to spatio-temporal variability of lower trophic-level productivity along the California Current Ecosystem (CCE), predators must be capable of switching prey or foraging areas in response to changes in environmental conditions and available forage. The Gulf of the Farallones in central California represents a biodiversity hotspot and contains the largest common murre (Uria aalge) colonies along the CCE. During spring, one of the West Coast's most important Chinook salmon (Oncorhynchus tshawytscha) populations out-migrates into the Gulf of the Farallones. We quantify the effect of predation on juvenile Chinook salmon associated with ecosystem-level variability by integrating long-term time series of environmental conditions (upwelling, river discharge), forage species abundance within central CCE, and population size, at-sea distribution, and diet of the common murre. Our results demonstrate common murres typically forage in the vicinity of their offshore breeding sites, but in years in which their primary prey, pelagic young-of-year rockfish (Sebastesspp.), are less available they forage for adult northern anchovies (Engraulis mordax) nearshore. Incidentally, while foraging inshore, common murre consumption of out-migrating juvenile Chinook salmon, which are collocated with northern anchovy, increases and population survival of the salmon is significantly reduced. Results support earlier findings that show timing and strength of upwelling, and the resultant forage fish assemblage, is related to Chinook salmon recruitment variability in the CCE, but we extend those results by demonstrating the significance of top-down impacts associated with these bottom-up dynamics. Our results demonstrate the complexity of ecosystem interactions and impacts between higher trophic-level predators and their prey, complexities necessary to quantify in order to parameterize ecosystem models and evaluate likely outcomes of ecosystem management options.

  2. Environmental conditions and prey-switching by a seabird predator impact juvenile salmon survival

    Science.gov (United States)

    Wells, Brian K.; Santora, Jarrod A.; Henderson, Mark J.; Warzybok, Pete; Jahncke, Jaime; Bradley, Russell W.; Huff, David D.; Schroeder, Isaac D.; Nelson, Peter; Field, John C.; Ainley, David G.

    2017-10-01

    Due to spatio-temporal variability of lower trophic-level productivity along the California Current Ecosystem (CCE), predators must be capable of switching prey or foraging areas in response to changes in environmental conditions and available forage. The Gulf of the Farallones in central California represents a biodiversity hotspot and contains the largest common murre (Uria aalge) colonies along the CCE. During spring, one of the West Coast's most important Chinook salmon (Oncorhynchus tshawytscha) populations out-migrates into the Gulf of the Farallones. We quantify the effect of predation on juvenile Chinook salmon associated with ecosystem-level variability by integrating long-term time series of environmental conditions (upwelling, river discharge), forage species abundance within central CCE, and population size, at-sea distribution, and diet of the common murre. Our results demonstrate common murres typically forage in the vicinity of their offshore breeding sites, but in years in which their primary prey, pelagic young-of-year rockfish (Sebastes spp.), are less available they forage for adult northern anchovies (Engraulis mordax) nearshore. Incidentally, while foraging inshore, common murre consumption of out-migrating juvenile Chinook salmon, which are collocated with northern anchovy, increases and population survival of the salmon is significantly reduced. Results support earlier findings that show timing and strength of upwelling, and the resultant forage fish assemblage, is related to Chinook salmon recruitment variability in the CCE, but we extend those results by demonstrating the significance of top-down impacts associated with these bottom-up dynamics. Our results demonstrate the complexity of ecosystem interactions and impacts between higher trophic-level predators and their prey, complexities necessary to quantify in order to parameterize ecosystem models and evaluate likely outcomes of ecosystem management options.

  3. Identifying salmon lice transmission characteristics between Faroese salmon farms

    DEFF Research Database (Denmark)

    Kragesteen, Trondur J.; Simonsen, Knud; Visser, AW

    2017-01-01

    between farms is of vital importance in developing treatment management plans to combat salmon lice infestations. Using a particle tracking model forced by tidal currents, we show that Faroese aquaculture farms form a complex network. In some cases as high as 10% of infectious salmon lice released at one...... farm site enter a neighboring fjord containing another farm site. Farms were characterized as emitters, receivers or isolated, and we could identify two clusters of farms that were largely isolated from each other. The farm characteristics are a valuable input for the development of management plans...... for the entire Faroese salmon industry...

  4. Anthropogenic tracers, endocrine disrupting chemicals, and endocrine disruption in Minnesota lakes

    Science.gov (United States)

    Writer, J.H.; Barber, L.B.; Brown, G.K.; Taylor, H.E.; Kiesling, R.L.; Ferrey, M.L.; Jahns, N.D.; Bartell, S.E.; Schoenfuss, H.L.

    2010-01-01

    Concentrations of endocrine disrupting chemicals and endocrine disruption in fish were determined in 11 lakes across Minnesota that represent a range of trophic conditions and land uses (urban, agricultural, residential, and forested) and in which wastewater treatment plant discharges were absent. Water, sediment, and passive polar organic integrative samplers (POCIS) were analyzed for steroidal hormones, alkylphenols, bisphenol A, and other organic and inorganic molecular tracers to evaluate potential non-point source inputs into the lakes. Resident fish from the lakes were collected, and caged male fathead minnows were deployed to evaluate endocrine disruption, as indicated by the biological endpoints of plasma vitellogenin and gonadal histology. Endocrine disrupting chemicals, including bisphenol A, 17??-estradiol, estrone, and 4-nonylphenol were detected in 90% of the lakes at part per trillion concentrations. Endocrine disruption was observed in caged fathead minnows and resident fish in 90% of the lakes. The widespread but variable occurrence of anthropogenic chemicals in the lakes and endocrine disruption in fish indicates that potential sources are diverse, not limited to wastewater treatment plant discharges, and not entirely predictable based on trophic status and land use. ?? 2010.

  5. Anthropogenic tracers, endocrine disrupting chemicals, and endocrine disruption in Minnesota lakes.

    Science.gov (United States)

    Writer, Jeffrey H; Barber, Larry B; Brown, Greg K; Taylor, Howard E; Kiesling, Richard L; Ferrey, Mark L; Jahns, Nathan D; Bartell, Steve E; Schoenfuss, Heiko L

    2010-12-01

    Concentrations of endocrine disrupting chemicals and endocrine disruption in fish were determined in 11 lakes across Minnesota that represent a range of trophic conditions and land uses (urban, agricultural, residential, and forested) and in which wastewater treatment plant discharges were absent. Water, sediment, and passive polar organic integrative samplers (POCIS) were analyzed for steroidal hormones, alkylphenols, bisphenol A, and other organic and inorganic molecular tracers to evaluate potential non-point source inputs into the lakes. Resident fish from the lakes were collected, and caged male fathead minnows were deployed to evaluate endocrine disruption, as indicated by the biological endpoints of plasma vitellogenin and gonadal histology. Endocrine disrupting chemicals, including bisphenol A, 17β-estradiol, estrone, and 4-nonylphenol were detected in 90% of the lakes at part per trillion concentrations. Endocrine disruption was observed in caged fathead minnows and resident fish in 90% of the lakes. The widespread but variable occurrence of anthropogenic chemicals in the lakes and endocrine disruption in fish indicates that potential sources are diverse, not limited to wastewater treatment plant discharges, and not entirely predictable based on trophic status and land use. Published by Elsevier B.V.

  6. Salmon Population Summary - Impacts of climate change on Pacific salmon

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This work involves 1) synthesizing information from the literature and 2) modeling impacts of climate change on specific aspects of salmon life history and...

  7. Disruptive innovations

    OpenAIRE

    Viglia, Giampaolo; H. Werthner; Buhalis, Dimitrios

    2016-01-01

    The diffusion of disrupting innovations has generated significant market changes, modifying the dominant logic and affecting the strategic positioning of companies. This structural change is affecting market structure, the networks and the services that tourism players are supposed to use (Gretzel et al. 2015). One can also refer to the notion of digital infrastructure, which provides a nice framework that connects the different stakeholders, their relations as well as internal dynamics. At t...

  8. [Treatment of patients with trophic ulcer].

    Science.gov (United States)

    Karapetian, G É; Iakimov, S V; Mikitin, I L; Kochetova, L V; Pakhomova, R A

    2014-01-01

    The authors present the investigation of inpatient treatment of 137 patients with trophic ulcers of venous aethiology. All the patients were hospitalized in the "Road clinical hospital" on the Krasnoyarsk station. A comparative analysis of treatment results of the patients with trophic ulcers using different medical methods was made. The efficacy of combined use of low-frequency ultrasound and ozone therapy was proved.

  9. Trophic mechanisms for exercise-induced stress resilience: Potential role of interactions between BDNF and galanin

    Directory of Open Access Journals (Sweden)

    Philip V Holmes

    2014-07-01

    Full Text Available Current concepts of the neurobiology of stress-related disorders such as anxiety and depression emphasize disruptions in neural plasticity and neurotrophins. The potent trophic actions of exercise therefore represent not only an effective means for prevention and treatment of these disorders, they also afford the opportunity to employ exercise paradigms as a basic research tool to uncover the neurobiological mechanisms underlying these disorders. Novel approaches to studying stress-related disorders focus increasingly on trophic factor signaling in corticolimbic circuits that both mediate and regulate cognitive, behavioral, and physiological responses to deleterious stress. Recent evidence demonstrates that the neural plasticity supported by these trophic mechanisms is vital for establishing and maintaining resilience to stress. Therapeutic interventions that promote these mechanisms, be they pharmacological, behavioral, or environmental, may therefore prevent or reverse stress-related mental illness by enhancing resilience. The present paper will provide an overview of trophic mechanisms responsible for the enhancement of resilience by voluntary exercise with an emphasis on BDNF, galanin, and interactions between these two trophic factors.

  10. Effects of trophic ecology and habitat use on maternal transfer of contaminants in four species of young of the year lamniform sharks.

    Science.gov (United States)

    Lyons, Kady; Carlisle, Aaron; Preti, Antonella; Mull, Christopher; Blasius, Mary; O'Sullivan, John; Winkler, Chuck; Lowe, Christopher G

    2013-09-01

    Organic contaminant and total mercury concentrations were compared in four species of lamniform sharks over several age classes to examine bioaccumulation patterns and gain insights into trophic ecology. Contaminants found in young of the year (YOY) sharks were assumed to be derived from maternal sources and used as a proxy to investigate factors that influence maternal offloading processes. YOY white (Carcharodon carcharias) and mako (Isurus oxyrinchus) sharks had comparable and significantly higher concentrations of PCBs, DDTs, pesticides, and mercury than YOY thresher (Alopias vulpinus) or salmon (Lamna ditropis) sharks. A significant positive relationship was found between YOY contaminant loads and maternal trophic position, suggesting that trophic ecology is one factor that plays an important role in maternal offloading. Differences in organic contaminant signatures and contaminant concentration magnitudes among species corroborated what is known about species habitat use and may be used to provide insights into the feeding ecology of these animals. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  11. Lipids and Composition of Fatty Acids of Saccharina latissima Cultivated Year-round in Integrated Multi-trophic Aquaculture

    DEFF Research Database (Denmark)

    Silva Marinho, Goncalo; Holdt, Susan Løvstad; Jacobsen, Charlotte

    2015-01-01

    This study is evaluating the seasonal lipid and fatty acid composition of the brown seaweed Saccharina latissima. Biomass was sampled throughout the year (bi-monthly) at the commercial cultivation site near a fish farm in an integrated multi-trophic aquaculture (IMTA) and at a reference site...... such as cabbage and lettuce. Compared to fat (salmon) and lean fish (cod) this seaweed species contains higher proportions of ARA and SDA, but lower EPA (only cod) and DHA. Conclusively, the season of harvest is important for the choice of lipid quantity and quality, but the marine vegetables provide better...

  12. Sustainable Disruptions

    DEFF Research Database (Denmark)

    Friis, Silje Alberthe Kamille; Kjær, Lykke Bloch

    2016-01-01

    Since 2012 the Sustainable Disruptions (SD) project at the Laboratory for Sustainability at Design School Kolding (DK) has developed and tested a set of design thinking tools, specifically targeting the barriers to economically, socially, and environmentally sustainable business development....... The tools have been applied in practice in collaboration with 11 small and medium sized companies (SMEs). The study investigates these approaches to further understand how design thinking can contribute to sustainable transition in a business context. The study and the findings are relevant to organizations...... invested in the issue of sustainable business development, in particular the leaders and employees of SMEs, but also to design education seeking new ways to consciously handle and teach the complexity inherent in sustainable transformation. Findings indicate that the SD design thinking approach contributes...

  13. Trophic transfer of persistent organochlorine contaminants (OCs) within an Arctic marine food web from the southern Beaufort-Chukchi Seas

    Energy Technology Data Exchange (ETDEWEB)

    Hoekstra, P.F.; O' Hara, T.M.; Fisk, A.T.; Borgaa, K.; Solomon, K.R.; Muir, D.C.G

    2003-08-01

    The trophic status and biomagnification of persistent OCs within the near-shore Beaufort-Chukchi Seas food web from Barrow, AK is discussed. - Stable isotope values ({delta}{sup 13}C, {delta}{sup 15}N) and concentrations of persistent organochlorine contaminants (OCs) were determined to evaluate the near-shore marine trophic status of biota and biomagnification of OCs from the southern Beaufort-Chukchi Seas (1999-2000) near Barrow, AK. The biota examined included zooplankton (Calanus spp.), fish species such as arctic cod (Boreogadus saida), arctic char (Salvelinus alpinus), pink salmon (Oncorhynchus gorbuscha), and fourhorn sculpin (Myoxocephalus quadricornis), along with marine mammals, including bowhead whales (Balaena mysticetus), beluga whales (Delphinapterus leucas), ringed seals (Phoca hispida) and bearded seals (Erignathus barbatus). The isotopically derived trophic position of biota from the Beaufort-Chukchi Seas marine food web, avian fauna excluded, is similar to other coastal food webs in the Arctic. Concentrations of OCs in marine mammals were significantly greater than in fish and corresponded with determined trophic level. In general, OCs with the greatest food web magnification factors (FWMFs) were those either formed due to biotransformation (e.g. p,p'-DDE, oxychlordane) or considered recalcitrant (e.g. {beta}-HCH, 2,4,5-Cl substituted PCBs) in most biota, whereas concentrations of OCs that are considered to be readily eliminated (e.g. {gamma}-HCH) did not correlate with trophic level. Differences in physical-chemical properties of OCs, feeding strategy and possible biotransformation were reflected in the variable biomagnification between fish and marine mammals. The FWMFs in the Beaufort-Chukchi Seas region were consistent with reported values in the Canadian Arctic and temperate food webs, but were statistically different than FWMFs from the Barents and White Seas, indicating that the spatial variability of OC contamination in top

  14. Treatment of Parkinson's disease with trophic factors

    National Research Council Canada - National Science Library

    Peterson, Amie L; Nutt, John G

    2008-01-01

    Trophic factors are proteins that support and protect subpopulations of cells. A number have been reported to act on dopaminergic neurons in vitro and in vivo, making them potential therapeutic candidates for Parkinson's disease...

  15. Trophic ulcers in the carpal tunnel syndrome

    Directory of Open Access Journals (Sweden)

    Abelardo Q.-C. Araújo

    1993-09-01

    Full Text Available A patient with carpal tunnel syndrome (CTS and trophic ulcers is described. Despite the healing of the ulcers after surgery for CTS, the severe sensory deficit and the electrophysiological tests have not shown any significant improvement. We think these findings argue against the hypothesis of the sensory deficit being responsible for the trophic ulcers. We favor a major role for the sympathetic disturbances as the main cause for those lesions.

  16. Simple trophic modules for complex food webs

    OpenAIRE

    Bascompte, Jordi; Carlos J. Melián

    2005-01-01

    There are two common approaches to food webs. On the one hand, empirical studies have described aggregate statistical measures of many-species food webs. On the other hand, theoretical studies have explored the dynamic properties of simple tri-trophic food chains (i.e., trophic modules). The question remains to what extent results based on simple modules are relevant for whole food webs. Here we bridge between these two independent research agendas by exploring the relative fr...

  17. Protecting the endangered lake salmon

    Energy Technology Data Exchange (ETDEWEB)

    Soimakallio, H.; Oesch, P. [ed.

    1997-11-01

    In addition to the Ringed Seal, the labyrinthine Saimaa lake system created after the Ice Age also trapped a species of salmon, whose entire life cycle became adapted to fresh water. In order to improve the living conditions of this lake salmon which - like the ringed seal - is today classified as an endangered species, an intensive research programme has been launched. The partners include the Finnish Game and Fisheries Research Institute, fishing and environmental authorities and - in collaboration with UPM-Kymmene Oy and Kuurnan Voima Oy - the IVO subsidiary Pamilo Oy

  18. Infectious salmon anaemia virus (ISAV) mucosal infection in Atlantic salmon.

    Science.gov (United States)

    Aamelfot, Maria; McBeath, Alastair; Christiansen, Debes H; Matejusova, Iveta; Falk, Knut

    2015-10-21

    All viruses infecting fish must cross the surface mucosal barrier to successfully enter a host. Infectious salmon anaemia virus (ISAV), the causative agent of the economically important infectious salmon anaemia (ISA) in Atlantic salmon, Salmo salar L., has been shown to use the gills as its entry point. However, other entry ports have not been investigated despite the expression of virus receptors on the surface of epithelial cells in the skin, the gastrointestinal (GI) tract and the conjunctiva. Here we investigate the ISAV mucosal infection in Atlantic salmon after experimental immersion (bath) challenge and in farmed fish collected from a confirmed outbreak of ISA in Norway. We show for the first time evidence of early replication in several mucosal surfaces in addition to the gills, including the pectoral fin, skin and GI tract suggesting several potential entry points for the virus. Initially, the infection is localized and primarily infecting epithelial cells, however at later stages it becomes systemic, infecting the endothelial cells lining the circulatory system. Viruses of low and high virulence used in the challenge revealed possible variation in virus progression during infection at the mucosal surfaces.

  19. 50 CFR 226.205 - Critical habitat for Snake River sockeye salmon, Snake River fall chinook salmon, and Snake River...

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Critical habitat for Snake River sockeye salmon, Snake River fall chinook salmon, and Snake River spring/summer chinook salmon. 226.205 Section... Snake River sockeye salmon, Snake River fall chinook salmon, and Snake River spring/summer chinook...

  20. Trophic hierarchies illuminated via amino acid isotopic analysis.

    Directory of Open Access Journals (Sweden)

    Shawn A Steffan

    Full Text Available Food web ecologists have long sought to characterize the trophic niches of animals using stable isotopic analysis. However, distilling trophic position from isotopic composition has been difficult, largely because of the variability associated with trophic discrimination factors (inter-trophic isotopic fractionation and routing. We circumvented much of this variability using compound-specific isotopic analysis (CSIA. We examined the (15N signatures of amino acids extracted from organisms reared in pure culture at four discrete trophic levels, across two model communities. We calculated the degree of enrichment at each trophic level and found there was a consistent trophic discrimination factor (~7.6‰. The constancy of the CSIA-derived discrimination factor permitted unprecedented accuracy in the measurement of animal trophic position. Conversely, trophic position estimates generated via bulk-(15N analysis significantly underestimated trophic position, particularly among higher-order consumers. We then examined the trophic hierarchy of a free-roaming arthropod community, revealing the highest trophic position (5.07 and longest food chain ever reported using CSIA. High accuracy in trophic position estimation brings trophic function into sharper focus, providing greater resolution to the analysis of food webs.

  1. Trophic level responses differ as climate warms in Ireland

    Science.gov (United States)

    Donnelly, Alison; Yu, Rong; Liu, Lingling

    2015-08-01

    Effective ecosystem functioning relies on successful species interaction. However, this delicate balance may be disrupted if species do not respond to environmental change at a similar rate. Here we examine trends in the timing of spring phenophases of groups of species occupying three trophic levels as a potential indicator of ecosystem response to climate warming in Ireland. The data sets were of varying length (1976-2009) and from varying locations: (1) timing of leaf unfolding and May Shoot of a range of broadleaf and conifer tree species, (2) first appearance dates of a range of moth species, and (3) first arrival dates of a range of spring migrant birds. All three groups revealed a statistically significant ( Pinterdependent phenophases as temperatures rise. Even though these data were not specifically collected to examine climate warming impacts, we conclude that such data may be used as an early warning indicator and as a means to monitor the potential for future ecosystem disruption to occur as climate warms.

  2. Collaborative Approaches to Flow Restoration in Intermittent Salmon-Bearing Streams: Salmon Creek, CA, USA

    National Research Council Canada - National Science Library

    Cleo Woelfle-Erskine

    2017-01-01

    ... and sustainably by their users. Understanding the linkages between salmon and groundwater is one major focus of salmon recovery and climate change adaptation planning in central California and increasingly throughout the Pacific Northwest...

  3. Comparative Genomics Identifies Candidate Genes for Infectious Salmon Anemia (ISA) Resistance in Atlantic Salmon (Salmo salar)

    OpenAIRE

    Li, Jieying; Keith A. Boroevich; Koop, Ben F; Davidson, William S.

    2010-01-01

    Infectious salmon anemia (ISA) has been described as the hoof and mouth disease of salmon farming. ISA is caused by a lethal and highly communicable virus, which can have a major impact on salmon aquaculture, as demonstrated by an outbreak in Chile in 2007. A quantitative trait locus (QTL) for ISA resistance has been mapped to three microsatellite markers on linkage group (LG) 8 (Chr 15) on the Atlantic salmon genetic map. We identified bacterial artificial chromosome (BAC) clones and three f...

  4. Piscivores, Trophic Cascades, and Lake Management

    Directory of Open Access Journals (Sweden)

    Ray W. Drenner

    2002-01-01

    Full Text Available The concept of cascading trophic interactions predicts that an increase in piscivore biomass in lakes will result in decreased planktivorous fish biomass, increased herbivorous zooplankton biomass, and decreased phytoplankton biomass. Though often accepted as a paradigm in the ecological literature and adopted by lake managers as a basis for lake management strategies, the trophic cascading interactions hypothesis has not received the unequivocal support (in the form of rigorous experimental testing that might be expected of a paradigm. Here we review field experiments and surveys, testing the hypothesis that effects of increasing piscivore biomass will cascade down through the food web yielding a decline in phytoplankton biomass. We found 39 studies in the scientific literature examining piscivore effects on phytoplankton biomass. Of the studies, 22 were confounded by supplemental manipulations (e.g., simultaneous reduction of nutrients or removal of planktivores and could not be used to assess piscivore effects. Of the 17 nonconfounded studies, most did not find piscivore effects on phytoplankton biomass and therefore did not support the trophic cascading interactions hypothesis. However, the trophic cascading interactions hypothesis also predicts that lake systems containing piscivores will have lower phytoplankton biomass for any given phosphorus concentration. Based on regression analyses of chlorophyll�total phosphorus relationships in the 17 nonconfounded piscivore studies, this aspect of the trophic cascading interactions hypothesis was supported. The slope of the chlorophyll vs. total phosphorus regression was lower in lakes with planktivores and piscivores compared with lakes containing only planktivores but no piscivores. We hypothesize that this slope can be used as an indicator of “functional piscivory” and that communities with extremes of functional piscivory (zero and very high represent classical 3- and 4-trophic level

  5. Increased susceptibility to infectious salmon anemia virus (ISAv) in Lepeophtheirus salmonis – infected Atlantic salmon

    Science.gov (United States)

    The salmon louse and infectious salmon anemia virus (ISAv) are the two most significant pathogens of concern to the Atlantic salmon (Salmo salar) aquaculture industry. However, the interactions between sea lice and ISAv, as well as the impact of a prior sea lice infection on the susceptibility of th...

  6. 'Trophic' and 'source' amino acids in trophic estimation: a likely metabolic explanation.

    Science.gov (United States)

    O'Connell, T C

    2017-06-01

    Amino acid nitrogen isotopic analysis is a relatively new method for estimating trophic position. It uses the isotopic difference between an individual's 'trophic' and 'source' amino acids to determine its trophic position. So far, there is no accepted explanation for the mechanism by which the isotopic signals in 'trophic' and 'source' amino acids arise. Yet without a metabolic understanding, the utility of nitrogen isotopic analyses as a method for probing trophic relations, at either bulk tissue or amino acid level, is limited. I draw on isotopic tracer studies of protein metabolism, together with a consideration of amino acid metabolic pathways, to suggest that the 'trophic'/'source' groupings have a fundamental metabolic origin, to do with the cycling of amino-nitrogen between amino acids. 'Trophic' amino acids are those whose amino-nitrogens are interchangeable, part of a metabolic amino-nitrogen pool, and 'source' amino acids are those whose amino-nitrogens are not interchangeable with the metabolic pool. Nitrogen isotopic values of 'trophic' amino acids will reflect an averaged isotopic signal of all such dietary amino acids, offset by the integrated effect of isotopic fractionation from nitrogen cycling, and modulated by metabolic and physiological effects. Isotopic values of 'source' amino acids will be more closely linked to those of equivalent dietary amino acids, but also modulated by metabolism and physiology. The complexity of nitrogen cycling suggests that a single identifiable value for 'trophic discrimination factors' is unlikely to exist. Greater consideration of physiology and metabolism should help in better understanding observed patterns in nitrogen isotopic values.

  7. The trophic position of dead autochthonous organic material and its treatment in trophic analyses

    OpenAIRE

    Gaedke, Ursula; Straile, Dietmar

    1997-01-01

    1. The importance of the recycling of organic matter for the overall carbon and nutrient flow in a food web, e.g., by the microbial loop has been recognized for pelagic and other ecosystems during the last decade. In contrast, analyses of the trophic food web structure conducted, e.g., by network analysis based on mass-balanced flow diagrams (i.e., computation of, e.g., trophic positionsand transfer efficiencies, organismal composition of trophic levels) which greatly contribute to our unders...

  8. Molecular mechanisms of continuous light inhibition of Atlantic salmon parr-smolt transformation

    DEFF Research Database (Denmark)

    Steffansson, Sigurd O.E.; Nielsen, Tom O.; Ebbesson, Lars O.E.

    2007-01-01

    . The present study addresses the endocrine and molecular mechanisms controlling the development of hypo-osmoregulatory ability and how artificial photoperiod can disrupt these changes. Juvenile Atlantic salmon reared under constant light (LL) from first feeding, were separated into two groups, and exposed...... that continuous light prevents the completion of parr-smolt transformation at a very basic level, disrupting the natural up-regulation of key elements of the endocrine system involved in the regulation of the parr-smolt transformation, and consequently inhibiting the smoltification-related increase in expression...

  9. Predation on Chinook Salmon parr by hatchery salmonids and Fallfish in the Salmon River, New York

    Science.gov (United States)

    Johnson, James H.; Nack, Christopher C.; Chalupnicki, Marc; Abbett, Ross; McKenna, James E.

    2016-01-01

    Naturally reproduced Chinook Salmon Oncorhynchus tshawytscha contribute substantially to the fishery in Lake Ontario. The Salmon River, a Lake Ontario tributary in New York, produces the largest numbers of naturally spawned Chinook Salmon, with parr abundance in the river often exceeding 10 million. In the spring of each year, large numbers of hatchery salmonid yearlings—potential predators of Chinook Salmon parr—are released into the Salmon River by the New York State Department of Environmental Conservation. We sought to examine predation on Chinook Salmon parr in the Salmon River during May and June prior to out-migration. Over the 4 years examined (2009–2012), annual consumption of Chinook Salmon parr by hatchery-released yearling steelhead O. mykiss and Coho Salmon O. kisutch ranged from 1.5 to 3.3 million and from 0.4 to 2.1 million, respectively. In 2009, Fallfish Semotilus corporalis were estimated to consume 2.9 million Chinook Salmon parr. Predation was higher in May, when the average TL of Chinook Salmon parr was 44.5 mm, than in June. Fallfish were also important predators of naturally reproduced steelhead subyearlings, consuming an estimated 800,000 steelhead in 2009. Hatchery-released yearling salmonids consumed 13.8–15.3% of the Chinook Salmon parr that were estimated to be present in the Salmon River during 2010–2012. Earlier releases of hatchery salmonid yearlings could reduce the riverine consumption of Chinook Salmon parr by facilitating the out-migration of yearlings prior to Chinook Salmon emergence.

  10. Trophic and environmental drivers of the Sechura Bay Ecosystem (Peru) over an ENSO cycle

    Science.gov (United States)

    Taylor, Marc H.; Wolff, Matthias; Vadas, Flora; Yamashiro, Carmen

    2008-03-01

    Interannual environmental variability in Peru is dominated by the El Niño Southern Oscillation (ENSO). The most dramatic changes are associated with the warm El Niño (EN) phase (opposite the cold La Niña phase), which disrupts the normal coastal upwelling and affects the dynamics of many coastal marine and terrestrial resources. This study presents a trophic model for Sechura Bay, located at the northern extension of the Peruvian upwelling system, where ENSO-induced environmental variability is most extreme. Using an initial steady-state model for the year 1996, we explore the dynamics of the ecosystem through the year 2003 (including the strong EN of 1997/98 and the weaker EN of 2002/03). Based on support from literature, we force biomass of several non-trophically-mediated ‘drivers’ (e.g. Scallops, Benthic detritivores, Octopus, and Littoral fish) to observe whether the fit between historical and simulated changes (by the trophic model) is improved. The results indicate that the Sechura Bay Ecosystem is a relatively inefficient system from a community energetics point of view, likely due to the periodic perturbations of ENSO. A combination of high system productivity and low trophic level target species of invertebrates (i.e. scallops) and fish (i.e. anchoveta) results in high catches and an efficient fishery. The importance of environmental drivers is suggested, given the relatively small improvements in the fit of the simulation with the addition of trophic drivers on remaining functional groups’ dynamics. An additional multivariate regression model is presented for the scallop Argopecten purpuratus, which demonstrates a significant correlation between both spawning stock size and riverine discharge-mediated mortality on catch levels. These results are discussed in the context of the appropriateness of trophodynamic modeling in relatively open systems, and how management strategies may be focused given the highly environmentally influenced marine

  11. Trophically available metal - A variable feast

    Energy Technology Data Exchange (ETDEWEB)

    Rainbow, Philip S., E-mail: p.rainbow@nhm.ac.uk [Department of Zoology, Natural History Museum, Cromwell Rd, London SW7 5BD (United Kingdom); Luoma, Samuel N. [Department of Zoology, Natural History Museum, Cromwell Rd, London SW7 5BD (United Kingdom); John Muir Institute of the Environment, University of California, Davis, CA 95616 (United States); Wang Wenxiong [College of Marine and Environmental Sciences, State Key Laboratory for Marine Environmental Sciences, Xiamen University, Fujian (China)

    2011-10-15

    Assimilation of trace metals by predators from prey is affected by the physicochemical form of the accumulated metal in the prey, leading to the concept of a Trophically Available Metal (TAM) component in the food item definable in terms of particular subcellular fractions of accumulated metal. As originally defined TAM consists of soluble metal forms and metal associated with cell organelles, the combination of separated fractions which best explained particular results involving a decapod crustacean predator feeding on bivalve mollusc tissues. Unfortunately TAM as originally defined has subsequently frequently been used in the literature as an absolute description of that component of accumulated metal that is trophically available in all prey to all consumers. It is now clear that what is trophically available varies between food items, consumers and metals. TAM as originally defined should be seen as a useful starting hypothesis, not as a statement of fact. - Trophically Available Metal (TAM), the component of accumulated metal in food that is taken up by a feeding animal, varies with food type and consumer.

  12. Stable Isotopes Reveal Trophic Partitioning and Trophic Plasticity of a Larval Amphibian Guild

    OpenAIRE

    Rosa Arribas; Carmen Díaz-Paniagua; Stephane Caut; Ivan Gomez-Mestre

    2015-01-01

    Temporary ponds are highly variable systems where resource availability and community structure change extensively over time, and consequently the food web is highly dynamic. Amphibians play a critical role both as consumers and prey in aquatic communities and yet there is still little information on the trophic status of most amphibians. More importantly, little is known about the extent to which they can alter their trophic ecology in response to changing conditions. We experimentally inves...

  13. 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

    to infective salmon lice larvae in the laboratory immediately before release in the inner part of the fjord to simulate a naturally high infection pressure. Groups of infected Atlantic salmon (n = 20) and brown trout (n = 12) were also retained in the hatchery to control the infection intensity and lice...

  14. Trophic diversity of Poznań Lakeland lakes

    Directory of Open Access Journals (Sweden)

    Dzieszko Piotr

    2015-06-01

    Full Text Available The main goal of the presented work is to determine the current trophic state of 31 lakes located in Poznań Lakeland. These lakes are included in the lake monitoring programme executed by the Voivodship Environmental Protection Inspectorate in Poznań. The place in the trophic classification for investigated lakes was determined as well as the relationships between their trophic state indices. The trophic state of investigated lakes in the research area is poor. More than a half of the investigated lakes are eutrophic. Depending on the factor that is taken into account the trophic state of investigated lakes differs radically.

  15. THE FUTURE OF PACIFIC NORTHWEST SALMON: ANATOMY OF A CRISIS

    Science.gov (United States)

    Salmon are categorized biologically into two groups: Pacific salmon or Atlantic salmon. All seven species of Pacific salmon on both sides of the North Pacific Ocean have declined substantially from historic levels, but large runs still occur in northern British Columbia, Yukon,...

  16. Geomagnetic imprinting: A unifying hypothesis of long-distance natal homing in salmon and sea turtles.

    Science.gov (United States)

    Lohmann, Kenneth J; Putman, Nathan F; Lohmann, Catherine M F

    2008-12-09

    Several marine animals, including salmon and sea turtles, disperse across vast expanses of ocean before returning as adults to their natal areas to reproduce. How animals accomplish such feats of natal homing has remained an enduring mystery. Salmon are known to use chemical cues to identify their home rivers at the end of spawning migrations. Such cues, however, do not extend far enough into the ocean to guide migratory movements that begin in open-sea locations hundreds or thousands of kilometers away. Similarly, how sea turtles reach their nesting areas from distant sites is unknown. However, both salmon and sea turtles detect the magnetic field of the Earth and use it as a directional cue. In addition, sea turtles derive positional information from two magnetic elements (inclination angle and intensity) that vary predictably across the globe and endow different geographic areas with unique magnetic signatures. Here we propose that salmon and sea turtles imprint on the magnetic field of their natal areas and later use this information to direct natal homing. This novel hypothesis provides the first plausible explanation for how marine animals can navigate to natal areas from distant oceanic locations. The hypothesis appears to be compatible with present and recent rates of field change (secular variation); one implication, however, is that unusually rapid changes in the Earth's field, as occasionally occur during geomagnetic polarity reversals, may affect ecological processes by disrupting natal homing, resulting in widespread colonization events and changes in population structure.

  17. Modeling parasite dynamics on farmed salmon for precautionary conservation management of wild salmon.

    Directory of Open Access Journals (Sweden)

    Luke A Rogers

    Full Text Available Conservation management of wild fish may include fish health management in sympatric populations of domesticated fish in aquaculture. We developed a mathematical model for the population dynamics of parasitic sea lice (Lepeophtheirus salmonis on domesticated populations of Atlantic salmon (Salmo salar in the Broughton Archipelago region of British Columbia. The model was fit to a seven-year dataset of monthly sea louse counts on farms in the area to estimate population growth rates in relation to abiotic factors (temperature and salinity, local host density (measured as cohort surface area, and the use of a parasiticide, emamectin benzoate, on farms. We then used the model to evaluate management scenarios in relation to policy guidelines that seek to keep motile louse abundance below an average three per farmed salmon during the March-June juvenile wild Pacific salmon (Oncorhynchus spp. migration. Abiotic factors mediated the duration of effectiveness of parasiticide treatments, and results suggest treatment of farmed salmon conducted in January or early February minimized average louse abundance per farmed salmon during the juvenile wild salmon migration. Adapting the management of parasites on farmed salmon according to migrations of wild salmon may therefore provide a precautionary approach to conserving wild salmon populations in salmon farming regions.

  18. Modeling Parasite Dynamics on Farmed Salmon for Precautionary Conservation Management of Wild Salmon

    Science.gov (United States)

    Rogers, Luke A.; Peacock, Stephanie J.; McKenzie, Peter; DeDominicis, Sharon; Jones, Simon R. M.; Chandler, Peter; Foreman, Michael G. G.; Revie, Crawford W.; Krkošek, Martin

    2013-01-01

    Conservation management of wild fish may include fish health management in sympatric populations of domesticated fish in aquaculture. We developed a mathematical model for the population dynamics of parasitic sea lice (Lepeophtheirus salmonis) on domesticated populations of Atlantic salmon (Salmo salar) in the Broughton Archipelago region of British Columbia. The model was fit to a seven-year dataset of monthly sea louse counts on farms in the area to estimate population growth rates in relation to abiotic factors (temperature and salinity), local host density (measured as cohort surface area), and the use of a parasiticide, emamectin benzoate, on farms. We then used the model to evaluate management scenarios in relation to policy guidelines that seek to keep motile louse abundance below an average three per farmed salmon during the March–June juvenile wild Pacific salmon (Oncorhynchus spp.) migration. Abiotic factors mediated the duration of effectiveness of parasiticide treatments, and results suggest treatment of farmed salmon conducted in January or early February minimized average louse abundance per farmed salmon during the juvenile wild salmon migration. Adapting the management of parasites on farmed salmon according to migrations of wild salmon may therefore provide a precautionary approach to conserving wild salmon populations in salmon farming regions. PMID:23577082

  19. Endocrine Disrupting Chemicals (EDCs)

    Science.gov (United States)

    ... Pacientes y Cuidadores Hormones and Health The Endocrine System Hormones Endocrine Disrupting Chemicals (EDCs) Steroid and Hormone Abuse Peer ... and Health › Endocrine Disrupting Chemicals (EDCs) The Endocrine System Hormones Endocrine Disrupting Chemicals (EDCs) EDCs Myth vs. Fact Steroid ...

  20. Correction to salmon et Al. (2014).

    Science.gov (United States)

    2015-02-01

    Reports an error in "Does adding an emotion component enhance the Triple P-Positive Parenting Program" by Karen Salmon, Cassandra Dittman, Matthew Sanders, Rebecca Burson and Josie Hammington (Journal of Family Psychology, 2014[Apr], Vol 28[2], 244-252). In the article, a disclaimer was inadvertently omitted from the author note. The disclaimer has been included. (The following abstract of the original article appeared in record 2014-07166-001.) This pilot study aimed to compare the efficacy of a regular offering of the group-delivered Triple P-Positive Parenting Program for child behavior problems with an enhanced version tailored to promote child emotion competence. Families of children between ages 3 and 6 years displaying early-onset conduct problems were randomly assigned to Group Triple P (GTP; final n = 18) or Emotion Enhanced Triple P (EETP; final n = 18), in which parents were encouraged to incorporate emotion labels and causes and to coach emotion competence during discussions of everyday emotional experiences with their child. Compared with parents who received GTP, parents who received EETP increased their discussion of emotion labels and emotion causes in conversations with their child at postintervention, but this advantage was lost by the 4-month follow-up. Parents in the EETP condition also used more emotion coaching postintervention and at follow-up. There were no differences at postintervention or follow-up in children's emotion knowledge skills. Postintervention improvement in disruptive child behavior was greater for GTP, but the groups converged at follow-up. Parents were similarly satisfied with both interventions. Overall, EETP showed little advantage over regular GTP delivery. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

  1. The trophic vacuum and the evolution of complex life cycles in trophically transmitted helminths.

    Science.gov (United States)

    Benesh, Daniel P; Chubb, James C; Parker, Geoff A

    2014-10-22

    Parasitic worms (helminths) frequently have complex life cycles in which they are transmitted trophically between two or more successive hosts. Sexual reproduction often takes place in high trophic-level (TL) vertebrates, where parasites can grow to large sizes with high fecundity. Direct infection of high TL hosts, while advantageous, may be unachievable for parasites constrained to transmit trophically, because helminth propagules are unlikely to be ingested by large predators. Lack of niche overlap between propagule and definitive host (the trophic transmission vacuum) may explain the origin and/or maintenance of intermediate hosts, which overcome this transmission barrier. We show that nematodes infecting high TL definitive hosts tend to have more successive hosts in their life cycles. This relationship was modest, though, driven mainly by the minimum TL of hosts, suggesting that the shortest trophic chains leading to a host define the boundaries of the transmission vacuum. We also show that alternative modes of transmission, like host penetration, allow nematodes to reach high TLs without intermediate hosts. We suggest that widespread omnivory as well as parasite adaptations to increase transmission probably reduce, but do not eliminate, the barriers to the transmission of helminths through the food web. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  2. Introgressive hybridization in a trophically polymorphic cichlid.

    Science.gov (United States)

    Hulsey, C Darrin; García-de-León, Francisco J

    2013-11-01

    Trophically polymorphic species could represent lineages that are rapidly diverging along an ecological axis or could phenotypically mark the collapse of species through introgressive hybridization. We investigated patterns of introgression between the trophically polymorphic cichlid fish Herichthys minckleyi and its relative H. cyanoguttatus using a combination of population genetics and species tree analyses. We first examined the distribution of mitochondrial haplotypes within the alternative H. minckleyi pharyngeal jaw morphotypes that are endemic to the small desert valley of Cuatro Ciénegas. We recovered two clusters of mitochondrial haplotypes. The first contained a number of slightly differentiated cytochrome b (cytb) haplotypes that showed some phylogeographic signal and were present in both jaw morphotypes. The other haplotype was monomorphic, highly differentiated from the other cluster, present in equal frequencies in the morphotypes, and identical to H. cyanoguttatus haplotypes found outside Cuatro Ciénegas. Then, we investigated whether H. minckleyi individuals with the H. cyanoguttatus cytb were more evolutionarily similar to H. cyanoguttatus or other H. minckleyi using a species tree analysis of 84 nuclear loci. Both H. minckleyi pharyngeal morphotypes, regardless of their cytb haplotype, were quite distinct from H. cyanoguttatus. However, hybridization could be blurring subdivision within H. minckleyi as the alternative jaw morphotypes were not genetically distinct from one another. Accounting for introgression from H. cyanoguttatus will be essential to understand the evolution of the trophically polymorphic cichlid H. minckleyi.

  3. Ecology. Can science rescue salmon?

    Science.gov (United States)

    Mann, C C; Plummer, M L

    2000-08-04

    At a press conference on 27 July, the National Marine Fisheries Service (NMFS) released a long-awaited plan to save the Columbia River's endangered salmon by restoring fish habitat, overhauling hatcheries, limiting harvest, and improving river flow. What the plan did not do, however, was call for immediate breaching of four dams on the Snake River, the Columbia's major tributary--an option that has been the subject of a nationwide environmental crusade. The NMFS will hold that option in abeyance while it sees whether the less drastic measures will do the trick. Responses from both sides were immediate and outraged.

  4. Multivariate models of adult Pacific salmon returns.

    Directory of Open Access Journals (Sweden)

    Brian J Burke

    Full Text Available Most modeling and statistical approaches encourage simplicity, yet ecological processes are often complex, as they are influenced by numerous dynamic environmental and biological factors. Pacific salmon abundance has been highly variable over the last few decades and most forecasting models have proven inadequate, primarily because of a lack of understanding of the processes affecting variability in survival. Better methods and data for predicting the abundance of returning adults are therefore required to effectively manage the species. We combined 31 distinct indicators of the marine environment collected over an 11-year period into a multivariate analysis to summarize and predict adult spring Chinook salmon returns to the Columbia River in 2012. In addition to forecasts, this tool quantifies the strength of the relationship between various ecological indicators and salmon returns, allowing interpretation of ecosystem processes. The relative importance of indicators varied, but a few trends emerged. Adult returns of spring Chinook salmon were best described using indicators of bottom-up ecological processes such as composition and abundance of zooplankton and fish prey as well as measures of individual fish, such as growth and condition. Local indicators of temperature or coastal upwelling did not contribute as much as large-scale indicators of temperature variability, matching the spatial scale over which salmon spend the majority of their ocean residence. Results suggest that effective management of Pacific salmon requires multiple types of data and that no single indicator can represent the complex early-ocean ecology of salmon.

  5. Multivariate models of adult Pacific salmon returns.

    Science.gov (United States)

    Burke, Brian J; Peterson, William T; Beckman, Brian R; Morgan, Cheryl; Daly, Elizabeth A; Litz, Marisa

    2013-01-01

    Most modeling and statistical approaches encourage simplicity, yet ecological processes are often complex, as they are influenced by numerous dynamic environmental and biological factors. Pacific salmon abundance has been highly variable over the last few decades and most forecasting models have proven inadequate, primarily because of a lack of understanding of the processes affecting variability in survival. Better methods and data for predicting the abundance of returning adults are therefore required to effectively manage the species. We combined 31 distinct indicators of the marine environment collected over an 11-year period into a multivariate analysis to summarize and predict adult spring Chinook salmon returns to the Columbia River in 2012. In addition to forecasts, this tool quantifies the strength of the relationship between various ecological indicators and salmon returns, allowing interpretation of ecosystem processes. The relative importance of indicators varied, but a few trends emerged. Adult returns of spring Chinook salmon were best described using indicators of bottom-up ecological processes such as composition and abundance of zooplankton and fish prey as well as measures of individual fish, such as growth and condition. Local indicators of temperature or coastal upwelling did not contribute as much as large-scale indicators of temperature variability, matching the spatial scale over which salmon spend the majority of their ocean residence. Results suggest that effective management of Pacific salmon requires multiple types of data and that no single indicator can represent the complex early-ocean ecology of salmon.

  6. Salmon-derived thrombin inhibits development of chronic pain through an endothelial barrier protective mechanism dependent on APC.

    Science.gov (United States)

    Smith, Jenell R; Galie, Peter A; Slochower, David R; Weisshaar, Christine L; Janmey, Paul A; Winkelstein, Beth A

    2016-02-01

    Many neurological disorders are initiated by blood-brain barrier breakdown, which potentiates spinal neuroinflammation and neurodegeneration. Peripheral neuropathic injuries are known to disrupt the blood-spinal cord barrier (BSCB) and to potentiate inflammation. But, it is not known whether BSCB breakdown facilitates pain development. In this study, a neural compression model in the rat was used to evaluate relationships among BSCB permeability, inflammation and pain-related behaviors. BSCB permeability increases transiently only after injury that induces mechanical hyperalgesia, which correlates with serum concentrations of pro-inflammatory cytokines, IL-7, IL-12, IL-1α and TNF-α. Mammalian thrombin dually regulates vascular permeability through PAR1 and activated protein C (APC). Since thrombin protects vascular integrity through APC, directing its affinity towards protein C, while still promoting coagulation, might be an ideal treatment for BSCB-disrupting disorders. Salmon thrombin, which prevents the development of mechanical allodynia, also prevents BSCB breakdown after neural injury and actively inhibits TNF-α-induced endothelial permeability in vitro, which is not evident the case for human thrombin. Salmon thrombin's production of APC faster than human thrombin is confirmed using a fluorogenic assay and APC is shown to inhibit BSCB breakdown and pain-related behaviors similar to salmon thrombin. Together, these studies highlight the impact of BSCB on pain and establish salmon thrombin as an effective blocker of BSCB, and resulting nociception, through its preferential affinity for protein C. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Interaction of growth hormone overexpression and nutritional status on pituitary gland clock gene expression in coho salmon, Oncorhynchus kisutch.

    Science.gov (United States)

    Kim, Jin-Hyoung; White, Samantha L; Devlin, Robert H

    2015-02-01

    Clock genes are involved in generating a circadian rhythm that is integrated with the metabolic state of an organism and information from the environment. Growth hormone (GH) transgenic coho salmon, Oncorhynchus kisutch, show a large increase in growth rate, but also attenuated seasonal growth modulations, modified timing of physiological transformations (e.g. smoltification) and disruptions in pituitary gene expression compared with wild-type salmon. In several fishes, circadian rhythm gene expression has been found to oscillate in the suprachiasmatic nucleus of the hypothalamus, as well as in multiple peripheral tissues, but this control system has not been examined in the pituitary gland nor has the effect of transgenic growth modification been examined. Thus, the daily expression of 10 core clock genes has been examined in pituitary glands of GH transgenic (T) and wild-type coho salmon (NT) entrained on a regular photocycle (12L: 12D) and provided either with scheduled feeding or had food withheld for 60 h. Most clock genes in both genotypes showed oscillating patterns of mRNA levels with light and dark cycles. However, T showed different amplitudes and patterns of expression compared with wild salmon, both in fed and starved conditions. The results from this study indicate that constitutive expression of GH is associated with changes in clock gene regulation, which may play a role in the disrupted behavioural and physiological phenotypes observed in growth-modified transgenic strains.

  8. A stochastic model for infectious salmon anemia (ISA) in Atlantic salmon farming

    OpenAIRE

    Scheel, Ida; Aldrin, Magne; Frigessi, Arnoldo; Jansen, Peder A

    2007-01-01

    Infectious salmon anemia (ISA) is one of the main infectious diseases in Atlantic salmon farming with major economical implications. Despite the strong regulatory interventions, the ISA epidemic is not under control, worldwide. We study the data covering salmon farming in Norway from 2002 to 2005 and propose a stochastic space-time model for the transmission of the virus. We model seaway transmission between farm sites, transmission through shared management and infrastructure, biomass effect...

  9. A Lota lota consumption: Trophic dynamics of nonnative Burbot in a valuable sport fishery

    Science.gov (United States)

    Klobucar, Stephen L.; Saunders, W. Carl; Budy, Phaedra

    2016-01-01

    Unintentional and illegal introductions of species disrupt food webs and threaten the success of managed sport fisheries. Although many populations of Burbot Lota lota are declining in the species’ native range, a nonnative population recently expanded into Flaming Gorge Reservoir (FGR), Wyoming–Utah, and threatens to disrupt predator–prey interactions within this popular sport fishery. To determine potential impacts on sport fishes, especially trophy Lake Trout Salvelinus namaycush, we assessed the relative abundance of Burbot and quantified the potential trophic or food web impacts of this population by using diet, stable isotope, and bioenergetic analyses. We did not detect a significant potential for food resource competition between Burbot and Lake Trout (Schoener’s overlap index = 0.13), but overall consumption by Burbot likely affects other sport fishes, as indicated by our analyses of trophic niche space. Diet analyses suggested that crayfish were important diet items across time (89.3% of prey by weight in autumn; 49.4% in winter) and across Burbot size-classes (small: 77.5% of prey by weight; medium: 76.6%; large: 39.7%). However, overall consumption by Burbot increases as water temperatures cool, and fish consumption by Burbot in FGR was observed to increase during winter. Specifically, large Burbot consumed more salmonids, and we estimated (bioenergetically) that up to 70% of growth occurred in late autumn and winter. Further, our population-wide consumption estimates indicated that Burbot could consume up to double the biomass of Rainbow Trout Oncorhynchus mykiss stocked annually (>1.3 × 105 kg; >1 million individuals) into FGR. Overall, we provide some of the first information regarding Burbot trophic interactions outside of the species’ native range; these findings can help to inform the management of sport fisheries if Burbot range expansion occurs elsewhere.

  10. The Genomic Basis of Trophic Strategy in Marine Bacteria

    National Research Council Canada - National Science Library

    Federico M. Lauro; Diane McDougald; Torsten Thomas; Timothy J. Williams; Suhelen Egan; Scott Rice; Matthew Z. DeMaere; Lily Ting; Haluk Ertan; Justin Johnson; Steven Ferriera; Alla Lapidus; Iain Anderson; Nikos Kyrpides; A. Christine Munk; Chris Defter; Cliff S. Hans; Mark V. Brown; Frank T. Robb; Staffan Kjelleberg; Ricardo Cavicchioli; Rita R. Colwell

    2009-01-01

    Many marine bacteria have evolved to grow optimally at either high (copiotrophic) or low (oligotrophic) nutrient concentrations, enabling different species to colonize distinct trophic habitats in the oceans...

  11. Seasonal succession in zooplankton feeding traits reveals trophic trait coupling

    DEFF Research Database (Denmark)

    Kenitz, Kasia; Visser, Andre; Mariani, Patrizio

    2017-01-01

    acquisition and photosynthesis, it also depends on grazing which couples feeding and motility traits across trophic guilds. Despite interannual variations in the species dominating the protist plankton community, the seasonal trait distribution reveals robust and repeatable seasonal patterns, changing between...... succession and shows how the physical environment controls the vertical structure of plankton communities, where ambush feeders exhibit a preference for greater depths during summer. We characterize the seasonal succession as trophic trait coupling and conjecture that this coupling leads to a trophic trait...... cascade where successive trophic levels alternate in their expression of activity traits further up in the food chain...

  12. CROOS - Collaborative Research on Oregon Ocean Salmon

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Goal 1: Improve understanding of salmon ocean ecology by integrating stock-specific distribution patterns over space and time with biological and environmental data....

  13. Karluk Lake sockeye salmon studies 1984: Draft

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes the findings of a study on Karluk Lake sockeye salmon. The objectives of the study were to: collect sediment core samples from Karluk Lake and...

  14. Pacific Northwest Salmon Habitat Project Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In the Pacific Northwest Salmon Habitat Project Database Across the Pacific Northwest, both public and private agents are working to improve riverine habitat for a...

  15. AFSC/ABL: Chum salmon allozyme baseline

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Allozymes from 46 loci were analyzed from chum salmon (Oncorhynchus keta) collected at 61 locations in southeast Alaska and northern British Columbia. Of the 42...

  16. LABORATORY DIAGNOSIS OF INFECTIOUS SALMON ANEMIA (ISA)

    DEFF Research Database (Denmark)

    Schyth, Brian Dall; Olesen, Niels Jørgen; Østergaard, Peter

    The first outbreak of ISA on the Faroe Islands was diagnosed in March 2000. Despite intensive surveillance, control and eradication of ISA, the disease has since spread to most of the Faroe Islands affecting about half of the 23 aquaculture farms. Sampling and laboratory diagnosis of ISA is perfo...... characterisation of the virus causing infectious salmon anemia in Atlantic salmon (Salmo salar L): an orthomyxo-like virus in a teleost....

  17. Salmon River Habitat Enhancement. 1990 Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    Rowe, Mike

    1991-12-01

    The annual report contains three individual subproject sections detailing tribal fisheries work completed during the summer and fall of 1990. Subproject I contains summaries of evaluation/monitoring efforts associated with the Bear Valley Creek, Idaho enhancement project. Subproject II contains an evaluation of the Yankee Fork of the Salmon River habitat enhancement project. Subproject III concerns the East Fork of the Salmon River, Idaho.

  18. Quantifying Temperature Effects on Fall Chinook Salmon

    Energy Technology Data Exchange (ETDEWEB)

    Jager, Yetta [ORNL

    2011-11-01

    The motivation for this study was to recommend relationships for use in a model of San Joaquin fall Chinook salmon. This report reviews literature pertaining to relationships between water temperature and fall Chinook salmon. The report is organized into three sections that deal with temperature effects on development and timing of freshwater life stages, temperature effects on incubation survival for eggs and alevin, and temperature effects on juvenile survival. Recommendations are made for modeling temperature influences for all three life stages.

  19. Disruption of Radiologist Workflow.

    Science.gov (United States)

    Kansagra, Akash P; Liu, Kevin; Yu, John-Paul J

    2016-01-01

    The effect of disruptions has been studied extensively in surgery and emergency medicine, and a number of solutions-such as preoperative checklists-have been implemented to enforce the integrity of critical safety-related workflows. Disruptions of the highly complex and cognitively demanding workflow of modern clinical radiology have only recently attracted attention as a potential safety hazard. In this article, we describe the variety of disruptions that arise in the reading room environment, review approaches that other specialties have taken to mitigate workflow disruption, and suggest possible solutions for workflow improvement in radiology. Copyright © 2015 Mosby, Inc. All rights reserved.

  20. Eco-Evolutionary Trophic Dynamics: Loss of Top Predators Drives Trophic Evolution and Ecology of Prey

    Science.gov (United States)

    Palkovacs, Eric P.; Wasserman, Ben A.; Kinnison, Michael T.

    2011-01-01

    Ecosystems are being altered on a global scale by the extirpation of top predators. The ecological effects of predator removal have been investigated widely; however, predator removal can also change natural selection acting on prey, resulting in contemporary evolution. Here we tested the role of predator removal on the contemporary evolution of trophic traits in prey. We utilized a historical introduction experiment where Trinidadian guppies (Poecilia reticulata) were relocated from a site with predatory fishes to a site lacking predators. To assess the trophic consequences of predator release, we linked individual morphology (cranial, jaw, and body) to foraging performance. Our results show that predator release caused an increase in guppy density and a “sharpening” of guppy trophic traits, which enhanced food consumption rates. Predator release appears to have shifted natural selection away from predator escape ability and towards resource acquisition ability. Related diet and mesocosm studies suggest that this shift enhances the impact of guppies on lower trophic levels in a fashion nuanced by the omnivorous feeding ecology of the species. We conclude that extirpation of top predators may commonly select for enhanced feeding performance in prey, with important cascading consequences for communities and ecosystems. PMID:21526156

  1. Eco-evolutionary trophic dynamics: loss of top predators drives trophic evolution and ecology of prey.

    Science.gov (United States)

    Palkovacs, Eric P; Wasserman, Ben A; Kinnison, Michael T

    2011-04-19

    Ecosystems are being altered on a global scale by the extirpation of top predators. The ecological effects of predator removal have been investigated widely; however, predator removal can also change natural selection acting on prey, resulting in contemporary evolution. Here we tested the role of predator removal on the contemporary evolution of trophic traits in prey. We utilized a historical introduction experiment where Trinidadian guppies (Poecilia reticulata) were relocated from a site with predatory fishes to a site lacking predators. To assess the trophic consequences of predator release, we linked individual morphology (cranial, jaw, and body) to foraging performance. Our results show that predator release caused an increase in guppy density and a "sharpening" of guppy trophic traits, which enhanced food consumption rates. Predator release appears to have shifted natural selection away from predator escape ability and towards resource acquisition ability. Related diet and mesocosm studies suggest that this shift enhances the impact of guppies on lower trophic levels in a fashion nuanced by the omnivorous feeding ecology of the species. We conclude that extirpation of top predators may commonly select for enhanced feeding performance in prey, with important cascading consequences for communities and ecosystems.

  2. Eco-evolutionary trophic dynamics: loss of top predators drives trophic evolution and ecology of prey.

    Directory of Open Access Journals (Sweden)

    Eric P Palkovacs

    Full Text Available Ecosystems are being altered on a global scale by the extirpation of top predators. The ecological effects of predator removal have been investigated widely; however, predator removal can also change natural selection acting on prey, resulting in contemporary evolution. Here we tested the role of predator removal on the contemporary evolution of trophic traits in prey. We utilized a historical introduction experiment where Trinidadian guppies (Poecilia reticulata were relocated from a site with predatory fishes to a site lacking predators. To assess the trophic consequences of predator release, we linked individual morphology (cranial, jaw, and body to foraging performance. Our results show that predator release caused an increase in guppy density and a "sharpening" of guppy trophic traits, which enhanced food consumption rates. Predator release appears to have shifted natural selection away from predator escape ability and towards resource acquisition ability. Related diet and mesocosm studies suggest that this shift enhances the impact of guppies on lower trophic levels in a fashion nuanced by the omnivorous feeding ecology of the species. We conclude that extirpation of top predators may commonly select for enhanced feeding performance in prey, with important cascading consequences for communities and ecosystems.

  3. Modelling emergent trophic strategies in plankton

    DEFF Research Database (Denmark)

    Andersen, Ken Haste; Aksnes, Dag L.; Berge, Terje

    2015-01-01

    Plankton are typically divided into phytoplankton and zooplankton in marine ecosystem models. Yet, most protists in the photic zone engage in some degree of phagotrophy, and it has been suggested that trophic strategy is really a continuum between pure phototrophs (phytoplankton) and pure...... a general trait-based model of a unicellular planktonic organism where size is a central trait and where nutrient uptake, photosynthesis and phagotrophy are determined by investments into these functions and by the physical constraints imposed by organism size. This framework provides simple predictions...

  4. Salmon River Habitat Enhancement, 1989 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Rowe, Mike

    1989-04-01

    This project was funded by the Bonneville Power Administration (BPA). The annual report contains three individual subproject papers detailing tribal fisheries work completed during the summer and fall of 1989. Subproject 1 contains summaries of evaluation/monitoring efforts associated with the Bear Valley Creek, Idaho enhancement project. Subproject 2 contains an evaluation of the Yankee Fork of the Salmon River habitat enhancement project. This report has been sub-divided into two parts: Part 1; stream evaluation and Part 2; pond series evaluation. Subproject 3 concerns the East Fork of the Salmon River, Idaho. This report summarizes the evaluation of the project to date including the 1989 pre-construction evaluation conducted within the East Fork drainage. Dredge mining has degraded spawning and rearing habitat for chinook salmon and steelhead trout in the Yankee Fork drainage of the Salmon River and in Bear Valley Creek. Mining, agricultural, and grazing practices degraded habitat in the East Fork of the Salmon River. Biological monitoring of the success of habitat enhancement for Bear Valley Creek and Yankee Fork are presented in this report. Physical and biological inventories prior to habitat enhancement in East Fork were also conducted. Four series of off-channel ponds of the Yankee Fork are shown to provide effective rearing habitat for chinook salmon. 45 refs., 49 figs., 24 tabs.

  5. Comparative anatomy of the dorsal hump in mature Pacific salmon.

    Science.gov (United States)

    Susuki, Kenta; Ban, Masatoshi; Ichimura, Masaki; Kudo, Hideaki

    2017-07-01

    Mature male Pacific salmon (Genus Oncorhynchus) demonstrate prominent morphological changes, such as the development of a dorsal hump. The degree of dorsal hump formation depends on the species in Pacific salmon. It is generally accepted that mature males of sockeye (O. nerka) and pink (O. gorbuscha) salmon develop most pronounced dorsal humps. The internal structure of the dorsal hump in pink salmon has been confirmed in detail. In this study, the dorsal hump morphologies were analyzed in four Pacific salmon species inhabiting Japan, masu (O. masou), sockeye, chum (O. keta), and pink salmon. The internal structure of the dorsal humps also depended on the species; sockeye and pink salmon showed conspicuous development of connective tissue and growth of bone tissues in the dorsal tissues. Masu and chum salmon exhibited less-pronounced increases in connective tissues and bone growth. Hyaluronic acid was clearly detected in dorsal hump connective tissue by histochemistry, except for in masu salmon. The lipid content in dorsal hump connective tissue was richer in masu and chum salmon than in sockeye and pink salmon. These results revealed that the patterns of dorsal hump formation differed among species, and especially sockeye and pink salmon develop pronounced dorsal humps through both increases in the amount of connective tissue and the growth of bone tissues. In contrast, masu and chum salmon develop their dorsal humps by the growth of bone tissues, rather than the development of connective tissue. © 2017 Wiley Periodicals, Inc.

  6. Salmon-Eating Grizzly Bears Exposed to Elevated Levels of Marine Derived Persistent Organic Pollutants

    Science.gov (United States)

    Christensen, J. R.; Ross, P. S.; Whiticar, M. J.

    2004-12-01

    The coastal grizzly bears of British Columbia (BC, Canada) rely heavily on salmon returning from the Pacific Ocean, whereas interior bears do not have access to or readily utilize this marine-derived food source. Since salmon have been shown to accumulate persistent organic pollutants (POPs) from the North Pacific Ocean, we hypothesized that salmon consumption by grizzly bears would be reflected by an increase in the POP burden. To test this hypothesis we collected hair and fat tissue from grizzlies at various locations around BC to compare salmon-eating (coastal) grizzlies to non-salmon-eating (interior) grizzlies. We characterized the feeding habits for each bear sampled by measuring the stable carbon and nitrogen isotope signature of their hair. The positive relationship between 13C/12C and 15N/14N isotopic ratios suggests that the majority of the meat portion of the diet of coastal grizzlies is coming from salmon, rather than from terrestrial or freshwater sources. By contrast, stable isotope ratios revealed that interior bears have an almost exclusive vegetarian diet with no marine influence. As hypothesized, the coastal grizzly bears have significantly greater OC pesticide and lower-brominated PBDE congener body burden than the interior grizzlies. We also found a positive relationship between C and N isotope ratios and these same POP contaminants in bear tissue. Overall, these results demonstrate that Pacific salmon represents a significant vector delivering both OC pesticides and PBDEs to BC coastal grizzly bears.

  7. Effect of exposure on salmon lice Lepeophtheirus salmonis population dynamics in Faroese salmon farms

    DEFF Research Database (Denmark)

    Patursson, Esbern J.; Simonsen, Knud; Visser, Andre

    2017-01-01

    of the freshwater exchange rate, the tidal exchange rate and dispersion by tidal currents. Salmon farms were ranked according to the rate of increase in the average numbers of salmon lice per fish. In a multiple linear regression, physical exposure together with temperature were shown to have a significant effect...

  8. Carotenoid dynamics in Atlantic salmon

    Directory of Open Access Journals (Sweden)

    Omholt Stig W

    2006-04-01

    Full Text Available Abstract Background Carotenoids are pigment molecules produced mainly in plants and heavily exploited by a wide range of organisms higher up in the food-chain. The fundamental processes regulating how carotenoids are absorbed and metabolized in vertebrates are still not fully understood. We try to further this understanding here by presenting a dynamic ODE (ordinary differential equation model to describe and analyse the uptake, deposition, and utilization of a carotenoid at the whole-organism level. The model focuses on the pigment astaxanthin in Atlantic salmon because of the commercial importance of understanding carotenoid dynamics in this species, and because deposition of carotenoids in the flesh is likely to play an important life history role in anadromous salmonids. Results The model is capable of mimicking feed experiments analyzing astaxanthin uptake and retention over short and long time periods (hours, days and years under various conditions. A sensitivity analysis of the model provides information on where to look for possible genetic determinants underlying the observed phenotypic variation in muscle carotenoid retention. Finally, the model framework is used to predict that a specific regulatory system controlling the release of astaxanthin from the muscle is not likely to exist, and that the release of the pigment into the blood is instead caused by the androgen-initiated autolytic degradation of the muscle in the sexually mature salmon. Conclusion The results show that a dynamic model describing a complex trait can be instrumental in the early stages of a project trying to uncover underlying determinants. The model provides a heuristic basis for an experimental research programme, as well as defining a scaffold for modelling carotenoid dynamics in mammalian systems.

  9. Carotenoid dynamics in Atlantic salmon.

    Science.gov (United States)

    Rajasingh, Hannah; Øyehaug, Leiv; Våge, Dag Inge; Omholt, Stig W

    2006-04-18

    Carotenoids are pigment molecules produced mainly in plants and heavily exploited by a wide range of organisms higher up in the food-chain. The fundamental processes regulating how carotenoids are absorbed and metabolized in vertebrates are still not fully understood. We try to further this understanding here by presenting a dynamic ODE (ordinary differential equation) model to describe and analyse the uptake, deposition, and utilization of a carotenoid at the whole-organism level. The model focuses on the pigment astaxanthin in Atlantic salmon because of the commercial importance of understanding carotenoid dynamics in this species, and because deposition of carotenoids in the flesh is likely to play an important life history role in anadromous salmonids. The model is capable of mimicking feed experiments analyzing astaxanthin uptake and retention over short and long time periods (hours, days and years) under various conditions. A sensitivity analysis of the model provides information on where to look for possible genetic determinants underlying the observed phenotypic variation in muscle carotenoid retention. Finally, the model framework is used to predict that a specific regulatory system controlling the release of astaxanthin from the muscle is not likely to exist, and that the release of the pigment into the blood is instead caused by the androgen-initiated autolytic degradation of the muscle in the sexually mature salmon. The results show that a dynamic model describing a complex trait can be instrumental in the early stages of a project trying to uncover underlying determinants. The model provides a heuristic basis for an experimental research programme, as well as defining a scaffold for modelling carotenoid dynamics in mammalian systems.

  10. Reciprocal Subsidies and Food Web Pathways Leading to Chum Salmon Fry in a Temperate Marine-Terrestrial Ecotone

    Science.gov (United States)

    Romanuk, Tamara N.; Levings, Colin D.

    2010-01-01

    Stable isotope analysis was used to determine the relative proportions of terrestrial and marine subsidies of carbon to invertebrates along a tidal gradient (low-intertidal, mid-intertidal, high-intertidal, supralittoral) and to determine the relative importance of terrestrial carbon in food web pathways leading to chum salmon fry Oncorhynchus keta (Walbaum) in Howe Sound, British Columbia. We found a clear gradient in the proportion of terrestrially derived carbon along the tidal gradient ranging from 68% across all invertebrate taxa in the supralittoral to 25% in the high-intertidal, 20% in the mid-intertidal, and 12% in the low-intertidal. Stable isotope values of chum salmon fry indicated carbon contributions from both terrestrial and marine sources, with terrestrially derived carbon ranging from 12.8 to 61.5% in the muscle tissue of chum salmon fry (mean 30%). Our results provide evidence for reciprocal subsidies of marine and terrestrially derived carbon on beaches in the estuary and suggest that the vegetated supralittoral is an important trophic link in supplying terrestrial carbon to nearshore food webs. PMID:20386705

  11. Adaptation Turning Points in River Restoration? The Rhine salmon case

    National Research Council Canada - National Science Library

    Bölscher, T; Slobbe, van, E.J.J; Vliet, van, M.T.H; Werners, S.E

    2013-01-01

    .... The paper shows that the moment at which salmon reintroduction may fail due to climate change can only be approximated because of inherent uncertainties in the interaction between salmon and its environment...

  12. Trophic assimilation efficiency markedly increases at higher trophic levels in four-level host-parasitoid food chain.

    Science.gov (United States)

    Sanders, Dirk; Moser, Andrea; Newton, Jason; van Veen, F J Frank

    2016-03-16

    Trophic assimilation efficiency (conversion of resource biomass into consumer biomass) is thought to be a limiting factor for food chain length in natural communities. In host-parasitoid systems, which account for the majority of terrestrial consumer interactions, a high trophic assimilation efficiency may be expected at higher trophic levels because of the close match of resource composition of host tissue and the consumer's resource requirements, which would allow for longer food chains. We measured efficiency of biomass transfer along an aphid-primary-secondary-tertiary parasitoid food chain and used stable isotope analysis to confirm trophic levels. We show high efficiency in biomass transfer along the food chain. From the third to the fourth trophic level, the proportion of host biomass transferred was 45%, 65% and 73%, respectively, for three secondary parasitoid species. For two parasitoid species that can act at the fourth and fifth trophic levels, we show markedly increased trophic assimilation efficiencies at the higher trophic level, which increased from 45 to 63% and 73 to 93%, respectively. In common with other food chains, δ(15)N increased with trophic level, with trophic discrimination factors (Δ(15)N) 1.34 and 1.49‰ from primary parasitoids to endoparasitic and ectoparasitic secondary parasitoids, respectively, and 0.78‰ from secondary to tertiary parasitoids. Owing to the extraordinarily high efficiency of hyperparasitoids, cryptic higher trophic levels may exist in host-parasitoid communities, which could alter our understanding of the dynamics and drivers of community structure of these important systems. © 2016 The Authors.

  13. Assessing Lake Trophic Status: A Proportional Odds Logistic Regression Model

    Science.gov (United States)

    Lake trophic state classifications are good predictors of ecosystem condition and are indicative of both ecosystem services (e.g., recreation and aesthetics), and disservices (e.g., harmful algal blooms). Methods for classifying trophic state are based off the foundational work o...

  14. Mechanisms of trophic partitioning within two fish communities ...

    African Journals Online (AJOL)

    Epipelagic fish species are segregated in three trophic guilds composed by species foraging on a limited range of prey. This observation is not consistent with the general view that these high trophic level species are opportunistic and generalist. The habitat seems to be the main driver of deep-sea fishes feeding partitioning ...

  15. Spawning Habitat Studies of Hanford Reach Fall Chinook Salmon (Oncorhynchus tshawytscha), Final Report.

    Energy Technology Data Exchange (ETDEWEB)

    Geist, David R.; Arntzen, Evan V.; Chien, Yi-Ju (Pacific Northwest National Laboratory)

    2009-03-02

    The Pacific Northwest National Laboratory conducted this study for the Bonneville Power Administration (BPA) with funding provided through the Northwest Power and Conservation Council(a) and the BPA Fish and Wildlife Program. The study was conducted in the Hanford Reach of the Columbia River. The goal of study was to determine the physical habitat factors necessary to define the redd capacity of fall Chinook salmon that spawn in large mainstem rivers like the Hanford Reach and Snake River. The study was originally commissioned in FY 1994 and then recommissioned in FY 2000 through the Fish and Wildlife Program rolling review of the Columbia River Basin projects. The work described in this report covers the period from 1994 through 2004; however, the majority of the information comes from the last four years of the study (2000 through 2004). Results from the work conducted from 1994 to 2000 were covered in an earlier report. More than any other stock of Pacific salmon, fall Chinook salmon (Oncorhynchus tshawytscha) have suffered severe impacts from the hydroelectric development in the Columbia River Basin. Fall Chinook salmon rely heavily on mainstem habitats for all phases of their life cycle, and mainstem hydroelectric dams have inundated or blocked areas that were historically used for spawning and rearing. The natural flow pattern that existed in the historic period has been altered by the dams, which in turn have affected the physical and biological template upon which fall Chinook salmon depend upon for successful reproduction. Operation of the dams to produce power to meet short-term needs in electricity (termed power peaking) produces unnatural fluctuations in flow over a 24-hour cycle. These flow fluctuations alter the physical habitat and disrupt the cues that salmon use to select spawning sites, as well as strand fish in near-shore habitat that becomes dewatered. The quality of spawning gravels has been affected by dam construction, flood protection, and

  16. Influence of climate change and trophic coupling across four trophic levels in the Celtic Sea.

    Directory of Open Access Journals (Sweden)

    Valentina Lauria

    Full Text Available Climate change has had profound effects upon marine ecosystems, impacting across all trophic levels from plankton to apex predators. Determining the impacts of climate change on marine ecosystems requires understanding the direct effects on all trophic levels as well as indirect effects mediated by trophic coupling. The aim of this study was to investigate the effects of climate change on the pelagic food web in the Celtic Sea, a productive shelf region in the Northeast Atlantic. Using long-term data, we examined possible direct and indirect 'bottom-up' climate effects across four trophic levels: phytoplankton, zooplankton, mid-trophic level fish and seabirds. During the period 1986-2007, although there was no temporal trend in the North Atlantic Oscillation index (NAO, the decadal mean Sea Surface Temperature (SST in the Celtic Sea increased by 0.66 ± 0.02 °C. Despite this, there was only a weak signal of climate change in the Celtic Sea food web. Changes in plankton community structure were found, however this was not related to SST or NAO. A negative relationship occurred between herring abundance (0- and 1-group and spring SST (0-group: p = 0.02, slope = -0.305 ± 0.125; 1-group: p = 0.04, slope = -0.410 ± 0.193. Seabird demographics showed complex species-specific responses. There was evidence of direct effects of spring NAO (on black-legged kittiwake population growth rate: p = 0.03, slope = 0.0314 ± 0.014 as well as indirect bottom-up effects of lagged spring SST (on razorbill breeding success: p = 0.01, slope = -0.144 ± 0.05. Negative relationships between breeding success and population growth rate of razorbills and common guillemots may be explained by interactions between mid-trophic level fish. Our findings show that the impacts of climate change on the Celtic Sea ecosystem is not as marked as in nearby regions (e.g. the North Sea, emphasizing the need for more research at regional scales.

  17. Patterns of change in climate and Pacific salmon production

    Science.gov (United States)

    Nathan J. Mantua

    2009-01-01

    For much of the 20th century a clear north-south inverse production pattern for Pacific salmon had a time dynamic that closely followed that of the Pacific Decadal Oscillation (PDO), which is the dominant pattern of North Pacific sea surface temperature variability. Total Alaska salmon production was high during warm regimes of the PDO, and total Alaska salmon...

  18. Farmed Atlantic salmon: potential invader in the Pacific Northwest?

    Science.gov (United States)

    Jonathan Thompson; Pete Bisson

    2008-01-01

    Commercial farming of Atlantic salmon in marine net-pens has become a booming industry. At present, approximately 130 salmon farms exist along the Pacific coast of North America. Most of these farms are in cold marine bays within British Columbia, where farmed salmon have become the province’s most valuable agricultural export. Each year, thousands of farmed Atlantic...

  19. Adhesion mechanism of salmon to polymer-coated can walls

    NARCIS (Netherlands)

    Dommershuijzen, H.; Hviid, L.; Hartog, den H.; Vereijken, J.

    2005-01-01

    Minimization of the amount of salmon adhering to the can wall after emptying is one of the convenience requirements of consumers of canned salmon. In order to achieve this, the mechanism by which salmon adheres to cans needs to be understood. The aim of this study was to provide such knowledge for

  20. Analysis of trophic interactions reveals highly plastic response to climate change in a tri-trophic High-Arctic ecosystem

    DEFF Research Database (Denmark)

    Mortensen, Lars O.; Schmidt, Niels Martin; Hoye, Toke T.

    2016-01-01

    -Arctic tri-trophic system of flowers, insects and waders (Charadriiformes), with latent factors representing phenology (timing of life history events) and performance (abundance or reproduction success) for each trophic level. The effects derived from the model demonstrated that the time of snowmelt directly...

  1. Alcohol disrupts sleep homeostasis.

    Science.gov (United States)

    Thakkar, Mahesh M; Sharma, Rishi; Sahota, Pradeep

    2015-06-01

    Alcohol is a potent somnogen and one of the most commonly used "over the counter" sleep aids. In healthy non-alcoholics, acute alcohol decreases sleep latency, consolidates and increases the quality (delta power) and quantity of NREM sleep during the first half of the night. However, sleep is disrupted during the second half. Alcoholics, both during drinking periods and during abstinences, suffer from a multitude of sleep disruptions manifested by profound insomnia, excessive daytime sleepiness, and altered sleep architecture. Furthermore, subjective and objective indicators of sleep disturbances are predictors of relapse. Finally, within the USA, it is estimated that societal costs of alcohol-related sleep disorders exceeds $18 billion. Thus, although alcohol-associated sleep problems have significant economic and clinical consequences, very little is known about how and where alcohol acts to affect sleep. In this review, we have described our attempts to unravel the mechanism of alcohol-induced sleep disruptions. We have conducted a series of experiments using two different species, rats and mice, as animal models. We performed microdialysis, immunohistochemical, pharmacological, sleep deprivation and lesion studies which suggest that the sleep-promoting effects of alcohol may be mediated via alcohol's action on the mediators of sleep homeostasis: adenosine (AD) and the wake-promoting cholinergic neurons of the basal forebrain (BF). Alcohol, via its action on AD uptake, increases extracellular AD resulting in the inhibition of BF wake-promoting neurons. Since binge alcohol consumption is a highly prevalent pattern of alcohol consumption and disrupts sleep, we examined the effects of binge drinking on sleep-wakefulness. Our results suggest that disrupted sleep homeostasis may be the primary cause of sleep disruption observed following binge drinking. Finally, we have also shown that sleep disruptions observed during acute withdrawal, are caused due to impaired

  2. Evolution of complex life cycles in trophically transmitted helminths. I. Host incorporation and trophic ascent.

    Science.gov (United States)

    Parker, G A; Ball, M A; Chubb, J C

    2015-02-01

    Links between parasites and food webs are evolutionarily ancient but dynamic: life history theory provides insights into helminth complex life cycle origins. Most adult helminths benefit by sexual reproduction in vertebrates, often high up food chains, but direct infection is commonly constrained by a trophic vacuum between free-living propagules and definitive hosts. Intermediate hosts fill this vacuum, facilitating transmission to definitive hosts. The central question concerns why sexual reproduction, and sometimes even larval growth, is suppressed in intermediate hosts, favouring growth arrest at larval maturity in intermediate hosts and reproductive suppression until transmission to definitive hosts? Increased longevity and higher growth in definitive hosts can generate selection for larger parasite body size and higher fecundity at sexual maturity. Life cycle length is increased by two evolutionary mechanisms, upward and downward incorporation, allowing simple (one-host) cycles to become complex (multihost). In downward incorporation, an intermediate host is added below the definitive host: models suggest that downward incorporation probably evolves only after ecological or evolutionary perturbations create a trophic vacuum. In upward incorporation, a new definitive host is added above the original definitive host, which subsequently becomes an intermediate host, again maintained by the trophic vacuum: theory suggests that this is plausible even under constant ecological/evolutionary conditions. The final cycle is similar irrespective of its origin (upward or downward). Insights about host incorporation are best gained by linking comparative phylogenetic analyses (describing evolutionary history) with evolutionary models (examining selective forces). Ascent of host trophic levels and evolution of optimal host taxa ranges are discussed. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary

  3. Stable Isotopes Reveal Trophic Partitioning and Trophic Plasticity of a Larval Amphibian Guild.

    Science.gov (United States)

    Arribas, Rosa; Díaz-Paniagua, Carmen; Caut, Stephane; Gomez-Mestre, Ivan

    2015-01-01

    Temporary ponds are highly variable systems where resource availability and community structure change extensively over time, and consequently the food web is highly dynamic. Amphibians play a critical role both as consumers and prey in aquatic communities and yet there is still little information on the trophic status of most amphibians. More importantly, little is known about the extent to which they can alter their trophic ecology in response to changing conditions. We experimentally investigated the effects of increased amphibian density, presence of intraguild competitors, and presence of native and invasive predators (either free or caged) on the trophic status of a Mediterranean amphibian guild, using stable isotopes. We observed variations in δ13C and δ15N isotopic values among amphibian species and treatments and differences in their food sources. Macrophytes were the most important food resource for spadefoot toad tadpoles (Pelobates cultripes) and relatively important for all anurans within the guild. High density and presence of P. cultripes tadpoles markedly reduced macrophyte biomass, forcing tadpoles to increase their feeding on detritus, algae and zooplankton, resulting in lower δ13C values. Native dytiscid predators only changed the isotopic signature of newts whereas invasive red swamp crayfish had an enormous impact on environmental conditions and greatly affected the isotopic values of amphibians. Crayfish forced tadpoles to increase detritus ingestion or other resources depleted in δ13C. We found that the opportunistic amphibian feeding was greatly conditioned by intra- and interspecific competition whereas non-consumptive predator effects were negligible. Determining the trophic plasticity of amphibians can help us understand natural and anthropogenic changes in aquatic ecosystems and assess amphibians' ability to adjust to different environmental conditions.

  4. Stable Isotopes Reveal Trophic Partitioning and Trophic Plasticity of a Larval Amphibian Guild.

    Directory of Open Access Journals (Sweden)

    Rosa Arribas

    Full Text Available Temporary ponds are highly variable systems where resource availability and community structure change extensively over time, and consequently the food web is highly dynamic. Amphibians play a critical role both as consumers and prey in aquatic communities and yet there is still little information on the trophic status of most amphibians. More importantly, little is known about the extent to which they can alter their trophic ecology in response to changing conditions. We experimentally investigated the effects of increased amphibian density, presence of intraguild competitors, and presence of native and invasive predators (either free or caged on the trophic status of a Mediterranean amphibian guild, using stable isotopes. We observed variations in δ13C and δ15N isotopic values among amphibian species and treatments and differences in their food sources. Macrophytes were the most important food resource for spadefoot toad tadpoles (Pelobates cultripes and relatively important for all anurans within the guild. High density and presence of P. cultripes tadpoles markedly reduced macrophyte biomass, forcing tadpoles to increase their feeding on detritus, algae and zooplankton, resulting in lower δ13C values. Native dytiscid predators only changed the isotopic signature of newts whereas invasive red swamp crayfish had an enormous impact on environmental conditions and greatly affected the isotopic values of amphibians. Crayfish forced tadpoles to increase detritus ingestion or other resources depleted in δ13C. We found that the opportunistic amphibian feeding was greatly conditioned by intra- and interspecific competition whereas non-consumptive predator effects were negligible. Determining the trophic plasticity of amphibians can help us understand natural and anthropogenic changes in aquatic ecosystems and assess amphibians' ability to adjust to different environmental conditions.

  5. Very low embryonic crude oil exposures cause lasting cardiac defects in salmon and herring.

    Science.gov (United States)

    Incardona, John P; Carls, Mark G; Holland, Larry; Linbo, Tiffany L; Baldwin, David H; Myers, Mark S; Peck, Karen A; Tagal, Mark; Rice, Stanley D; Scholz, Nathaniel L

    2015-09-08

    The 1989 Exxon Valdez disaster exposed embryos of pink salmon and Pacific herring to crude oil in shoreline spawning habitats throughout Prince William Sound, Alaska. The herring fishery collapsed four years later. The role of the spill, if any, in this decline remains one of the most controversial unanswered questions in modern natural resource injury assessment. Crude oil disrupts excitation-contraction coupling in fish heart muscle cells, and we show here that salmon and herring exposed as embryos to trace levels of crude oil grow into juveniles with abnormal hearts and reduced cardiorespiratory function, the latter a key determinant of individual survival and population recruitment. Oil exposure during cardiogenesis led to specific defects in the outflow tract and compact myocardium, and a hypertrophic response in spongy myocardium, evident in juveniles 7 to 9 months after exposure. The thresholds for developmental cardiotoxicity were remarkably low, suggesting the scale of the Exxon Valdez impact in shoreline spawning habitats was much greater than previously appreciated. Moreover, an irreversible loss of cardiac fitness and consequent increases in delayed mortality in oil-exposed cohorts may have been important contributors to the delayed decline of pink salmon and herring stocks in Prince William Sound.

  6. Interactive neurobehavioral toxicity of diazinon, malathion, and ethoprop to juvenile coho salmon.

    Science.gov (United States)

    Laetz, Cathy A; Baldwin, David H; Hebert, Vincent; Stark, John D; Scholz, Nathaniel L

    2013-03-19

    In western North America, mixtures of current use pesticides have been widely detected in streams and other aquatic habitats for threatened and endangered Pacific salmon and steelhead (Oncorhynchus sp.). These include organophosphate insecticides that inhibit acetylcholinesterase (AChE) enzyme activity in the salmon nervous system, thereby disrupting swimming and feeding behaviors. Several organophosphates have been shown to interact as mixtures to produce synergistic AChE inhibition at concentrations near or above the upper range of surface water detections in freshwater systems. To evaluate potential synergism at lower concentrations (near or below 1 part per billion), juvenile coho (Oncorhynchus kisutch) were exposed to a range of mixtures of diazinon-malathion and ethoprop-malathion below a cumulative 0.05 of the predicted EC50 for AChE inhibition, as determined from single chemical concentration-response curves. Brain enzyme inhibition was concentration-dependent, with a 90% reduction and a significant decrease in spontaneous swimming speed at the highest binary mixture concentrations evaluated (diazinon-malathion at 2.6 and 1.1 μg/L, respectively; ethoprop-malathion at 2.8 and 1.2 μg/L, respectively). Brain enzyme activity gradually recovered over six weeks. Our findings extend earlier observations of organophosphate synergism in salmon and reveal an unusually steep concentration-response relationship across a mere 2-fold increase in mixture concentration.

  7. The effect of nonylphenol on gene expression in Atlantic salmon smolts

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, Laura S., E-mail: lrobertson@usgs.gov [USGS, Leetown Science Center, 11649 Leetown Road, Kearneysville, WV 25430 (United States); McCormick, Stephen D., E-mail: smccormick@usgs.gov [USGS, Leetown Science Center, Conte Anadromous Fish Research Center, Turners Falls, MA 01376 (United States)

    2012-10-15

    The parr-smolt transformation in Atlantic salmon (Salmo salar) is a complex developmental process that culminates in the ability to migrate to and live in seawater. Exposure to environmental contaminants like nonylphenol can disrupt smolt development and may be a contributing factor in salmon population declines. We used GRASP 16K cDNA microarrays to investigate the effects of nonylphenol on gene expression in Atlantic salmon smolts. Nonylphenol exposure reduced gill Na{sup +}/K{sup +}-ATPase activity and plasma cortisol and triiodothyronine levels. Transcriptional responses were examined in gill, liver, olfactory rosettes, hypothalamus, and pituitary. Expression of 124 features was significantly altered in the liver of fish exposed to nonylphenol; little to no transcriptional effects were observed in other tissues. mRNA abundance of genes involved in protein biosynthesis, folding, modification, transport and catabolism; nucleosome assembly, cell cycle, cell differentiation, microtubule-based movement, electron transport, and response to stress increased in nonylphenol-treated fish. This study expands our understanding of the effect of nonylphenol on smolting and provides potential targets for development of biomarkers.

  8. Piscine reovirus, but not Jaundice Syndrome, was transmissible to Chinook Salmon, Oncorhynchus tshawytscha (Walbaum), Sockeye Salmon, Oncorhynchus nerka (Walbaum), and Atlantic Salmon, Salmo salar L.

    Science.gov (United States)

    Garver, Kyle A.; Marty, Gary D.; Cockburn, Sarah N.; Richard, Jon; Hawley, Laura M.; Müller, Anita; Thompson, Rachel L.; Purcell, Maureen K.; Saksida, Sonja M.

    2015-01-01

    A Jaundice Syndrome occurs sporadically among sea-pen-farmed Chinook Salmon in British Columbia, the westernmost province of Canada. Affected salmon are easily identified by a distinctive yellow discolouration of the abdominal and periorbital regions. Through traditional diagnostics, no bacterial or viral agents were cultured from tissues of jaundiced Chinook Salmon; however, piscine reovirus (PRV) was identified via RT-rPCR in all 10 affected fish sampled. By histopathology, Jaundice Syndrome is an acute to peracute systemic disease, and the time from first clinical signs to death is likely Salmon, Sockeye Salmon and Atlantic Salmon, intraperitoneally inoculated with a PRV-positive organ homogenate from jaundiced Chinook Salmon, developed no gross or microscopic evidence of jaundice despite persistence of PRV for the 5-month holding period. The results from this study demonstrate that the Jaundice Syndrome was not transmissible by injection of material from infected fish and that PRV was not the sole aetiological factor for the condition. Additionally, these findings showed the Pacific coast strain of PRV, while transmissible, was of low pathogenicity for Atlantic Salmon, Chinook Salmon and Sockeye Salmon.

  9. Assessment Of Trophic Status In Bali Strait

    Directory of Open Access Journals (Sweden)

    Umi Zakiyah

    2016-04-01

    Full Text Available The nutrient content in Banyuwangi coastal environment mostly caused by human activities along the coastal area of Bali strait especially in Banyuwangi surrounding areas. The change of organic element content in waters will directly affect plankton community structure and the aquatic trophic level. The aimed of this research were to analyze the plankton community structure, and to observe the quality of aquatic and determine Bali Strait especially Banyuwangi coastal area trophic level. This research was done in October 2015 at Banyuwangi coastal area. Methods used in this research was descriptive with seawater sampling for water quality analysis of several parameter such as nitrates (NO3, phosphates (PO4, TOM (Total Organic Matter and Chlorophyll-a, meanwhile other parameters were, temperature, pH, Dissolved Oxygen dan salinity from three different depth of three different stations, coastal area of Bangsring, Tandjung Wangi and Muncar. The results for water quality parameters showed that Bangsring coastal area was the most  healthy waters compared to Bangsring and Muncar. Meanwhile, there were tendency that the concentration mostly high in the surface and decrease along with the deeper depth. This condition presumed caused by the ARLINDO current that passed through Bali strait. Phytoplankton identified and calculated consisted of 3 division, namely Chlorophyta, Chrysophyta, and Cyanophyta with total density ranges between 4-2888 ind/ml. The value of diversity index phytoplankton (H’ ranges between 0,3-0,7. Based on the result it can be concluded that Banyuwangi coastal areas were at throphic level of  oligotrophic tended to mesotrophic in northern part and eutrophic especially in Muncar. Thus, it was suggested for the Government to prevent this area becoming more polluted in the future.

  10. Trophic conditions in Lake Winnisquam, New Hampshire

    Science.gov (United States)

    Frost, Leonard R.

    1977-01-01

    Lake Winnisquam has received treated domestic sewage for approximately 50 years and since June 1961 has been treated with copper sulfate to control the growth of nuisance algae. The Laconia City secondary sewage-treatment plant was upgraded in 1975 to include phosphorus removal. Phosphorus was not removed effectively until early 1976, and, therefore, the 1976 data are considered baseline or pre-phosphorus removal with respect to anticipated changes in the trophic condition of the lake. Effluent from the Laconia State School primary-treatment plant was diverted to the Laconia City plant in October 1976. Dissolved oxygen concentrations showed marked differences between the two basins comprising Lake Winnisquam. Phytoplankton samples showed similarities by algal group for all stations but algal genera varied between the upper and lower basins. Total phosphorus concentrations in the epilimnion ranged from 0.01 to 0.10 milligram per liter, and accumulation of total phosphorus in the hypolimnion resulted in concentrations up to 0.59 milligrams per liter. Chemical states of nutrients varied among the stations corresponding to the degree of depletion of hypolimnetic dissolved oxygen. Dissolved oxygen profiles were used to illustrate zones of algal production, respiration, and bacterial decomposition. The rate of depletion of dissolved oxygen in the hypolimnion was linearly related to time. Because change in the rate of hypolimnetic dissolved oxygen depletion is more easily measured than change of nutrient load in the lake, it is suggested it be used as an indicator of the response of the lake to change in trophic condition.

  11. Trigeminal Trophic Syndrome – Case Report

    Directory of Open Access Journals (Sweden)

    Boštjan Matos

    2015-05-01

    Full Text Available 1024x768 Trigeminal trophic syndrome is a rare condition resulting from compulsive self-manipulation of the skin after a peripheral or central injury to the trigeminal system. The classic triad consists of trigeminal anesthesia, facial paresthesias, and crescentric lateral nasal alar erosion and ulceration. Although the symptoms are visibly clear, the diagnosis is not easy to establish. The appearance of the ulcers mimics many other disease entities such as neoplasm, infection, granulomatous disease, vasculitis and factitial dermatitis. Trigeminal trophic syndrome should be considered with a positive neurologic history and when laboratory and biopsy workup is inconclusive. Once diagnosis is confirmed, treatment is complicated and often multidisciplinary. We report a case of a woman who developed a strictly unilateral crescent ulcer of the ala nasi after resection of an statoacoustic neurinoma. A clinician who is faced with a patient with nasal ulceration should consider this diagnosis.     Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

  12. Juvenile Salmonid Trophic Data - Ocean Survival of Salmonids

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A study to evaluate the role of changing ocean conditions on growth and survival of juvenile salmon from the Columbia River basin as they enter the Columbia River...

  13. Disruptive Mood Dysregulation Disorder

    Science.gov (United States)

    ... conduct research on numerous areas of study, including cognition, genetics, epidemiology, and psychiatry. The studies take place ... Leibenluft, Senior Investigator and Chief of the NIMH Emotion and Development Branch, explains the history of Disruptive ...

  14. Search and Disrupt

    DEFF Research Database (Denmark)

    Ørding Olsen, Anders

    This paper analyzes how external search is affected by strategic interest alignment among knowledge sources. I focus on misalignment arising from the heterogeneous effects of disruptive technologies by analyzing the influence of incumbents on 2,855 non-incumbents? external knowledge search efforts....... The efforts most likely to solve innovation problems obtained funding from the European Commission?s 7th Framework Program (2007-2013). The results show that involving incumbents improves search in complementary technologies, while demoting it when strategic interests are misaligned in disruptive technologies....... However, incumbent sources engaged in capability reconfiguration to accommodate disruption improve search efforts in disruptive technologies. The paper concludes that the value of external sources is contingent on more than their knowledge. Specifically, interdependence of sources in search gives rise...

  15. Digital disruption ?syndromes.

    Science.gov (United States)

    Sullivan, Clair; Staib, Andrew

    2017-05-18

    The digital transformation of hospitals in Australia is occurring rapidly in order to facilitate innovation and improve efficiency. Rapid transformation can cause temporary disruption of hospital workflows and staff as processes are adapted to the new digital workflows. The aim of this paper is to outline various types of digital disruption and some strategies for effective management. A large tertiary university hospital recently underwent a rapid, successful roll-out of an integrated electronic medical record (EMR). We observed this transformation and propose several digital disruption "syndromes" to assist with understanding and management during digital transformation: digital deceleration, digital transparency, digital hypervigilance, data discordance, digital churn and post-digital 'depression'. These 'syndromes' are defined and discussed in detail. Successful management of this temporary digital disruption is important to ensure a successful transition to a digital platform.What is known about this topic? Digital disruption is defined as the changes facilitated by digital technologies that occur at a pace and magnitude that disrupt established ways of value creation, social interactions, doing business and more generally our thinking. Increasing numbers of Australian hospitals are implementing digital solutions to replace traditional paper-based systems for patient care in order to create opportunities for improved care and efficiencies. Such large scale change has the potential to create transient disruption to workflows and staff. Managing this temporary disruption effectively is an important factor in the successful implementation of an EMR.What does this paper add? A large tertiary university hospital recently underwent a successful rapid roll-out of an integrated electronic medical record (EMR) to become Australia's largest digital hospital over a 3-week period. We observed and assisted with the management of several cultural, behavioural and

  16. Trophic state assessment of Bhindawas Lake, Haryana, India.

    Science.gov (United States)

    Saluja, Ridhi; Garg, J K

    2017-01-01

    Trophic state allows for identification of problems and pressures that an ecosystem faces as well as demarcation of remedial measures. This study focuses on spatial and temporal variations in the trophic state and detection of possible causes of its divergence in Bhindawas Lake, India. The trophic state of the lake undulated between eutrophic and hyper-eutrophic state throughout the study period. Higher phosphorus concentration within the lake ecosystem is the dominant causal factor for its eutrophic state. The influence of other water quality parameters has also been analyzed using Spearman's coefficient of correlation. Deviations between trophic state index (TSI)-chlorophyll-a (Chl-a), TSI-total phosphorus (TP), and TSI-Secchi depth (SD) pointed out that the lake is principally phosphorus limited, and its trophic status is influenced by non-algal turbidity to a large extent. Spatial analysis of trophic levels in geographic information system (GIS) helped in identification of pollution sources and chemical attributes affecting the trophic state of the lake. This study provides a rationale for further investigation of nutrient and sediment loading into the lake system and development of sustainable management and conservation strategy identifying suitable measures ascertaining the ecosystem integrity.

  17. Salmon: Robust Proxy Distribution for Censorship Circumvention

    Directory of Open Access Journals (Sweden)

    Douglas Frederick

    2016-10-01

    Full Text Available Many governments block their citizens’ access to much of the Internet. Simple workarounds are unreliable; censors quickly discover and patch them. Previously proposed robust approaches either have non-trivial obstacles to deployment, or rely on low-performance covert channels that cannot support typical Internet usage such as streaming video. We present Salmon, an incrementally deployable system designed to resist a censor with the resources of the “Great Firewall” of China. Salmon relies on a network of volunteers in uncensored countries to run proxy servers. Although any member of the public can become a user, Salmon protects the bulk of its servers from being discovered and blocked by the censor via an algorithm for quickly identifying malicious users. The algorithm entails identifying some users as especially trustworthy or suspicious, based on their actions. We impede Sybil attacks by requiring either an unobtrusive check of a social network account, or a referral from a trustworthy user.

  18. Cessation of a salmon decline with control of parasites

    KAUST Repository

    Peacock, Stephanie J.

    2013-04-01

    The resilience of coastal social-ecological systems may depend on adaptive responses to aquaculture disease outbreaks that can threaten wild and farm fish. A nine-year study of parasitic sea lice (Lepeophtheirus salmonis) and pink salmon (Oncorhynchus gorbuscha) from Pacific Canada indicates that adaptive changes in parasite management on salmon farms have yielded positive conservation outcomes. After four years of sea lice epizootics and wild salmon population decline, parasiticide application on salmon farms was adapted to the timing of wild salmon migrations. Winter treatment of farm fish with parasiticides, prior to the out-migration of wild juvenile salmon, has reduced epizootics of wild salmon without significantly increasing the annual number of treatments. Levels of parasites on wild juvenile salmon significantly influence the growth rate of affected salmon populations, suggesting that these changes in management have had positive outcomes for wild salmon populations. These adaptive changes have not occurred through formal adaptive management, but rather, through multi-stakeholder processes arising from a contentious scientific and public debate. Despite the apparent success of parasite control on salmon farms in the study region, there remain concerns about the long-term sustainability of this approach because of the unknown ecological effects of parasticides and the potential for parasite resistance to chemical treatments. © 2013 by the Ecological Society of America.

  19. Time-delayed subsidies: interspecies population effects in salmon.

    Directory of Open Access Journals (Sweden)

    Michelle C Nelson

    Full Text Available Cross-boundary nutrient inputs can enhance and sustain populations of organisms in nutrient-poor recipient ecosystems. For example, Pacific salmon (Oncorhynchus spp. can deliver large amounts of marine-derived nutrients to freshwater ecosystems through their eggs, excretion, or carcasses. This has led to the question of whether nutrients from one generation of salmon can benefit juvenile salmon from subsequent generations. In a study of 12 streams on the central coast of British Columbia, we found that the abundance of juvenile coho salmon was most closely correlated with the abundance of adult pink salmon from previous years. There was a secondary role for adult chum salmon and watershed size, followed by other physical characteristics of streams. Most of the coho sampled emerged in the spring, and had little to no direct contact with spawning salmon nutrients at the time of sampling in the summer and fall. A combination of techniques suggest that subsidies from spawning salmon can have a strong, positive, time-delayed influence on the productivity of salmon-bearing streams through indirect effects from previous spawning events. This is the first study on the impacts of nutrients from naturally-occurring spawning salmon on juvenile population abundance of other salmon species.

  20. Damped trophic cascades driven by fishing in model marine ecosystems

    DEFF Research Database (Denmark)

    Andersen, Ken Haste; Pedersen, Martin

    2010-01-01

    cascade triggered by the removal of top predators. Here we use a novel size- and trait-based model to explore how marine ecosystems might react to perturbations from different types of fishing pressure. The model explicitly resolves the whole life history of fish, from larvae to adults. The results show......The largest perturbation on upper trophic levels of many marine ecosystems stems from fishing. The reaction of the ecosystem goes beyond the trophic levels directly targeted by the fishery. This reaction has been described either as a change in slope of the overall size spectrum or as a trophic...

  1. Effects of diluted bitumen exposure on juvenile sockeye salmon: From cells to performance.

    Science.gov (United States)

    Alderman, Sarah L; Lin, Feng; Farrell, Anthony P; Kennedy, Christopher J; Gillis, Todd E

    2017-02-01

    Diluted bitumen (dilbit; the product of oil sands extraction) is transported through freshwater ecosystems critical to Pacific salmon. This is concerning, because crude oil disrupts cardiac development, morphology, and function in embryonic fish, and cardiac impairment in salmon can have major consequences on migratory success and fitness. The sensitivity of early life-stage salmon to dilbit and its specific cardiotoxic effects are unknown. Sockeye salmon parr were exposed to environmentally relevant concentrations of the water-soluble fraction (WSF) of dilbit for 1 wk and 4 wk, followed by an examination of molecular, morphological, and organismal endpoints related to cardiotoxicity. We show that parr are sensitive to WSF of dilbit, with total polycyclic aromatic hydrocarbon (PAH) concentrations of 3.5 µg/L sufficient to induce a liver biomarker of PAH exposure, and total PAH of 16.4 µg/L and 66.7 µg/L inducing PAH biomarkers in the heart. Furthermore, WSF of dilbit induces concentration-dependent cardiac remodeling coincident with performance effects: fish exposed to 66.7 µg/L total PAH have relatively fewer myocytes and more collagen in the compact myocardium and impaired swimming performance at 4 wk, whereas the opposite changes occur in fish exposed to 3.5 µg/L total PAH. The results demonstrate cardiac sensitivity to dilbit exposure that could directly impact sockeye migratory success. Environ Toxicol Chem 2017;36:354-360. © 2016 SETAC. © 2016 SETAC.

  2. The quality of cold smoked salmon

    DEFF Research Database (Denmark)

    Løje, Hanne

    2007-01-01

    The objective of this Ph. D. thesis was to study the liquid holding capacity/liquid loss of raw and smoked salmonids as affected by raw material and chill storage of the cold smoked product. The liquid holding capacity is an important quality parameter for cold smoked salmon. This study has shown...... of the smoked product affected the liquid holding capacity. Thus, the producers of cold smoked salmon should be aware of this and should have a careful control of the raw material especially regarding the lipid content....

  3. Salmon vulnerability maps - Effect of Climate Change on Salmon Population Vulnerability

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Steelhead (Oncorhynchus mykiss) and other Pacific salmon are threatened by unsustainable levels of harvest, genetic introgression from hatchery stocks and...

  4. Chinook salmon Genetic Stock Identification data - Genetic Stock Identification of Washington Chinook salmon

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This project evaluates data from coded wire tagging with that from parental based tagging to identify stock of origin for Chinook salmon landed in Washington state...

  5. Chum and pink salmon genetics - Genetic and life history variation of southern chum and pink salmon

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The distribution of genetic and life history variation in chum (Oncorhynchus keta) and pink (O. gorbuscha) salmon in their southern range in North America is key to...

  6. Salmon and steelhead genetics and genomics - Epigenetic and genomic variation in salmon and steelhead

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Conduct analyses of epigenetic and genomic variation in Chinook salmon and steelhead to determine influence on phenotypic expression of life history traits. Genetic,...

  7. Science for a wilder Anthropocene : Synthesis and future directions for trophic rewilding research

    NARCIS (Netherlands)

    Svenning, Jens Christian; Pedersen, Pil B M; Donlan, C. Josh; Ejrnæs, Rasmus; Faurby, Søren; Galetti, Mauro; Hansen, Dennis M.; Sandel, Brody; Sandom, Christopher J.; Terborgh, John W.; Vera, Frans W M

    2016-01-01

    Trophic rewilding is an ecological restoration strategy that uses species introductions to restore top-down trophic interactions and associated trophic cascades to promote self-regulating biodiverse ecosystems. Given the importance of large animals in trophic cascades and their widespread losses and

  8. Impact of human activities on nutrient and trophic status of some ...

    African Journals Online (AJOL)

    The nutrient and trophic status were used to assess the impact of human activities on lagoon by determining the trophic status of the lagoons and then using nutrient parameters and transparency in a form of model to predict the trophic status index (TSI) of the lagoon waters. The trophic index of Benya, Nakwa, Amisa and ...

  9. Differential rejection of salmon lice by pink and chum salmon: disease consequences and expression of proinflammatory genes.

    Science.gov (United States)

    Jones, Simon R M; Fast, Mark D; Johnson, Stewart C; Groman, David B

    2007-05-09

    The consequences of high (735 copepodids fish-1) and low (243 copepodids fish-1) level exposures of size-matched juvenile pink and chum salmon to Lepeophtheirus salmonis copepodids were examined. At both levels of exposure the prevalence and abundance of L. salmonis was significantly higher on chum salmon. In addition, the weight of exposed chum salmon following the high exposure was significantly less than that of unexposed chum salmon. At both exposures, the haematocrit of exposed chum salmon was significantly less than that of unexposed chum. Neither weight nor haematocrit of pink salmon was affected by exposures at these levels. Despite the presence of microscopic inflammatory lesions associated with attachment of L. salmonis on the epithelium of gill and fin of both salmon species, there were no mortalities following either exposure. A transient cortisol response was observed in chum salmon 21 d after low exposure. An earlier and quantitatively higher expression of the proinflammatory genes interleukin-8 (IL-8), tumour necrosis factor alpha-1 (TNFalpha-1) and interleukin-1beta (IL-1beta) in fin and head kidney of pink salmon suggested a mechanism of more rapid louse rejection in this species. Together, these observations indicate a relatively enhanced innate resistance to L. salmonis in the juvenile pink salmon compared with the juvenile chum salmon.

  10. Captive Rearing Initiative for Salmon River Chinook Salmon, 1998-1999 Progress Report.

    Energy Technology Data Exchange (ETDEWEB)

    Hassemer, Peter F.

    2001-04-01

    During 1999, the Idaho Department of Fish and Game (IDFG) continued developing techniques for the captive rearing of chinook salmon Oncorhynchus tshawytscha. Techniques under development included protocols for rearing juveniles in freshwater and saltwater hatchery environments, and fieldwork to collect brood year 1998 and 1999 juveniles and eggs and to investigate the ability of these fish to spawn naturally. Fish collected as juveniles were held for a short time at the Sawtooth Fish Hatchery and later transferred to the Eagle Fish Hatchery for rearing. Eyed-eggs were transferred immediately to the Eagle Fish Hatchery where they were disinfected and reared by family groups. When fish from either collection method reached approximately 60 mm, they were PIT tagged and reared separately by brood year and source stream. Sixteen different groups were in culture at IDFG facilities in 1999. Hatchery spawning activities of captive-reared chinook salmon produced eyed-eggs for outplanting in streamside incubation chambers in the West Fork Yankee Fork Salmon River (N=2,297) and the East Fork Salmon River (N=1,038). Additionally, a number of these eggs were maintained at the Eagle Fish Hatchery to ensure adequate brood year 1999 representation from these systems, and produced 279 and 87 juveniles from the West Fork Yankee Fork and East Fork Salmon River, respectively. Eyed-eggs were not collected from the West Fork Yankee Fork due to low adult escapement. Brood year 1998 juveniles were collected from the Lemhi River (N=191), West Fork Yankee Fork Salmon River (N=229), and East Fork Salmon River (N=185). Additionally, brood year 1999 eyed-eggs were collected from the Lemhi River (N=264) and East Fork Salmon River (N=143). Sixty-two and seven maturing adults were released into Bear Valley Creek (Lemhi River system) and the East Fork Salmon River, respectively, for spawning evaluation in 1999. Nine female carcasses from Bear Valley Creek were examined for egg retention, and of

  11. Captive Rearing Initiative for Salmon River Chinook Salmon, 1999 Progress Report.

    Energy Technology Data Exchange (ETDEWEB)

    Hassemer, Peter F.

    2001-04-01

    During 1999, the Idaho Department of Fish and Game (IDFG) continued developing techniques for the captive rearing of chinook salmon Oncorhynchus tshawytscha. Techniques under development included protocols for rearing juveniles in freshwater and saltwater hatchery environments, and fieldwork to collect brood year 1998 and 1999 juveniles and eggs and to investigate the ability of these fish to spawn naturally. Fish collected as juveniles were held for a short time at the Sawtooth Fish Hatchery and later transferred to the Eagle Fish Hatchery for rearing. Eyed-eggs were transferred immediately to the Eagle Fish Hatchery where they were disinfected and reared by family groups. When fish from either collection method reached approximately 60 mm, they were PIT tagged and reared separately by brood year and source stream. Sixteen different groups were in culture at IDFG facilities in 1999. Hatchery spawning activities of captive-reared chinook salmon produced eyed-eggs for outplanting in streamside incubation chambers in the West Fork Yankee Fork Salmon River (N=2,297) and the East Fork Salmon River (N=1,038). Additionally, a number of these eggs were maintained at the Eagle Fish Hatchery to ensure adequate brood year 1999 representation from these systems, and produced 279 and 87 juveniles from the West Fork Yankee Fork and East Fork Salmon River, respectively. Eyed-eggs were not collected from the West Fork Yankee Fork due to low adult escapement. Brood year 1998 juveniles were collected from the Lemhi River (N=191), West Fork Yankee Fork Salmon River (N=229), and East Fork Salmon River (N=185). Additionally, brood year 1999 eyed-eggs were collected from the Lemhi River (N=264) and East Fork Salmon River (N=143). Sixty-two and seven maturing adults were released into Bear Valley Creek (Lemhi River system) and the East Fork Salmon River, respectively, for spawning evaluation in 1999. Nine female carcasses from Bear Valley Creek were examined for egg retention, and of

  12. Comparative genomics identifies candidate genes for infectious salmon anemia (ISA) resistance in Atlantic salmon (Salmo salar).

    Science.gov (United States)

    Li, Jieying; Boroevich, Keith A; Koop, Ben F; Davidson, William S

    2011-04-01

    Infectious salmon anemia (ISA) has been described as the hoof and mouth disease of salmon farming. ISA is caused by a lethal and highly communicable virus, which can have a major impact on salmon aquaculture, as demonstrated by an outbreak in Chile in 2007. A quantitative trait locus (QTL) for ISA resistance has been mapped to three microsatellite markers on linkage group (LG) 8 (Chr 15) on the Atlantic salmon genetic map. We identified bacterial artificial chromosome (BAC) clones and three fingerprint contigs from the Atlantic salmon physical map that contains these markers. We made use of the extensive BAC end sequence database to extend these contigs by chromosome walking and identified additional two markers in this region. The BAC end sequences were used to search for conserved synteny between this segment of LG8 and the fish genomes that have been sequenced. An examination of the genes in the syntenic segments of the tetraodon and medaka genomes identified candidates for association with ISA resistance in Atlantic salmon based on differential expression profiles from ISA challenges or on the putative biological functions of the proteins they encode. One gene in particular, HIV-EP2/MBP-2, caught our attention as it may influence the expression of several genes that have been implicated in the response to infection by infectious salmon anemia virus (ISAV). Therefore, we suggest that HIV-EP2/MBP-2 is a very strong candidate for the gene associated with the ISAV resistance QTL in Atlantic salmon and is worthy of further study.

  13. Migration delays caused by anthropogenic barriers: modeling dams, temperature, and success on migrating salmon smolts

    Science.gov (United States)

    Marschall, Elizabeth A.; Mather, Martha E.; Parrish, Donna; Allison, Gary W.; McMenemy, James R.

    2011-01-01

    Disruption to migration is a growing problem for conservation and restoration of animal populations. Anthropogenic barriers along migration paths can delay or prolong migrations, which may result in a mismatch with migration-timing adaptations. To understand the interaction of dams (as barriers along a migration path), seasonally changing environmental conditions, timing of Atlantic salmon (Salmo salar) downstream migration, and ultimate migration success, we used 10 years of river temperature and discharge data as a template upon which we simulated downstream movement of salmon. Atlantic salmon is a cool-water species whose downstream migrating smolts must complete migration before river temperatures become too warm. We found that dams had a local effect on survival as well as a survival effect that was spatially and temporally removed from the encounter with the dam. While smolts are delayed by dams, temperatures downstream can reach lethal or near-lethal temperatures; as a result, the match between completion of migration and the window of appropriate migration conditions can be disrupted. The strength of this spatially and temporally removed effect is at least comparable to the local effects of dams in determining smolt migration success in the presence of dams. We also considered smolts from different tributaries, varying in distance from the river mouth, to assess the potential importance of locally adapted migration timing on the effect of barriers. Migration-initiation temperature affected modeled smolt survival differentially across tributaries, with the success of smolts from upstream tributaries being much more variable across years than that of smolts with a shorter distance to travel. As a whole, these results point to the importance of broadening our spatial and temporal view when managing migrating populations. We must consider not only how many individuals never make it across migration barriers, but also the spatially and temporally removed

  14. Migration delays caused by anthropogenic barriers: Modeling dams, temperature, and success of migrating salmon smolts

    Science.gov (United States)

    Marschall, E.A.; Mather, M. E.; Parrish, D.L.; Allison, G.W.; McMenemy, J.R.

    2011-01-01

    Disruption to migration is a growing problem for conservation and restoration of animal populations. Anthropogenic barriers along migration paths can delay or prolong migrations, which may result in a mismatch with migration-timing adaptations. To understand the interaction of dams (as barriers along a migration path), seasonally changing environmental conditions, timing of Atlantic salmon (Salmo salar) downstream migration, and ultimate migration success, we used 10 years of river temperature and discharge data as a template upon which we simulated downstream movement of salmon. Atlantic salmon is a cool-water species whose downstream migrating smolts must complete migration before river temperatures become too warm. We found that dams had a local effect on survival as well as a survival effect that was spatially and temporally removed from the encounter with the dam. While smolts are delayed by dams, temperatures downstream can reach lethal or near-lethal temperatures;as a result, the match between completion of migration and the window of appropriate migration conditions can be disrupted. The strength of this spatially and temporally removed effect is at least comparable to the local effects of dams in determining smolt migration success in the presence of dams. We also considered smolts from different tributaries, varying in distance from the river mouth, to assess the potential importance of locally adapted migration timing on the effect of barriers. Migration-initiation temperature affected modeled smolt survival differentially across tributaries, with the success of smolts from upstream tributaries being much more variable across years than that of smolts with a shorter distance to travel. As a whole, these results point to the importance of broadening our spatial and temporal view when managing migrating populations. We must consider not only how many individuals never make it across migration barriers, but also the spatially and temporally removed

  15. Collaborative Approaches to Flow Restoration in Intermittent Salmon-Bearing Streams: Salmon Creek, CA, USA

    Directory of Open Access Journals (Sweden)

    Cleo Woelfle-Erskine

    2017-03-01

    Full Text Available In Mediterranean-climate regions of California and southern Oregon, juvenile salmon depend on groundwater aquifers to sustain their tributary habitats through the dry summers. Along California’s North Coast streams, private property regimes on land have created commons tragedies in groundwater and salmon fisheries, both classic examples of commons that are often governed collectively and sustainably by their users. Understanding the linkages between salmon and groundwater is one major focus of salmon recovery and climate change adaptation planning in central California and increasingly throughout the Pacific Northwest. In this paper, I use extended field interviews and participant-observation in field ecology campaigns and regulatory forums to explore how, in one water-scarce, salmon-bearing watershed on California’s central coast, collaborators are synthesizing agency and landowner data on groundwater and salmon management. I focus on three projects undertaken by citizen scientists in collaboration with me and Gold Ridge Resource Conservation District staff: salmonid censuses, mapping of wet and dry stream reaches and well monitoring. I find that collaborative research initiated by local residents and agency personnel has, in some cases, created a new sense of ecological possibility in the region. I also consider some limitations of this collaborations, namely the lack of engagement with indigenous Pomo and Miwok tribal members, with the Confederated Tribes of Graton Rancheria and with farmworkers and other marginalized residents, and suggest strategies for deepening environmental justice commitments in future collaborative work.

  16. Salmon blood plasma: effective inhibitor of protease-laden Pacific whiting surimi and salmon mince.

    Science.gov (United States)

    Fowler, Matthew R; Park, Jae W

    2015-06-01

    The effect of salmon plasma (SP) from Chinook salmon on proteolytic inhibition was investigated. SP was found to inhibit both cysteine and serine proteases as well as protease extracted from Pacific whiting muscle. SP was found to contain a 55kDa cysteine protease inhibitor through SDS-PAGE inhibitor staining. Freeze dried salmon plasma (FSP) and salmon plasma concentrated by ultrafiltration (CSP) were tested for their ability to inhibit autolysis in Pacific whiting surimi and salmon mince at concentrations of 0.25%, 0.5%, 1%, and 2%. Pacific whiting surimi autolysis was inhibited by an average of 89% regardless of concentration while inhibition of salmon mince autolysis increased with concentration (psalmon mince autolysis (p<0.05). Serine protease inhibition decreased when SP heated above 40°C but was stable across a broad NaCl and pH range. Cysteine protease inhibitors exhibited good temperature, NaCl, and pH stability. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. The trophic requirements of selected underwood species occurring in forests

    National Research Council Canada - National Science Library

    Jarosław Lasota; Ewa Błońska; Tomasz Wanic; Maciej Zwydak

    2014-01-01

    ....). We focused on phytocenoses in the vicinity of natural forests in reserves and national parks of Polish lowlands and defined optimal types and subtypes of soil with trophic variations for each underwood species...

  18. Determination of trophic situation of Sarimsakli Dam Lake (Kayseri ...

    African Journals Online (AJOL)

    msakl. Dam Lake from May 2001 to June 2002 monthly to determine the trophic situation of lake. Additionally, physical parameters of water such as temperature, dissolved oxygen, electrical conductivity (EC), pH, light permeability were measured in ...

  19. Climate Change and Baleen Whale Trophic Cascades in Greenland

    Science.gov (United States)

    2009-09-30

    DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. Climate Change and Baleen Whale Trophic Cascades in Greenland...SUBTITLE Climate Change And Baleen Whale Trophic Cascades In Greenland 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S...2009. Polar bears in Northwest Greenland – An interview survey about the catch and the climate . Meddelelser om Grønland. [In Press, refereed] Heide

  20. The disruption management model.

    Science.gov (United States)

    McAlister, James

    2011-10-01

    Within all organisations, business continuity disruptions present a set of dilemmas that managers may not have dealt with before in their normal daily duties. The disruption management model provides a simple but effective management tool to enable crisis management teams to stay focused on recovery in the midst of a business continuity incident. The model has four chronological primary headlines, which steer the team through a quick-time crisis decision-making process. The procedure facilitates timely, systematic, rationalised and justified decisions, which can withstand post-event scrutiny. The disruption management model has been thoroughly tested within an emergency services environment and is proven to significantly support clear and concise decision making in a business continuity context.

  1. Emerging and Disruptive Technologies.

    Science.gov (United States)

    Kricka, Larry J

    2016-08-01

    Several emerging or disruptive technologies can be identified that might, at some point in the future, displace established laboratory medicine technologies and practices. These include increased automation in the form of robots, 3-D printing, technology convergence (e.g., plug-in glucose meters for smart phones), new point-of-care technologies (e.g., contact lenses with sensors, digital and wireless enabled pregnancy tests) and testing locations (e.g., Retail Health Clinics, new at-home testing formats), new types of specimens (e.g., cell free DNA), big biology/data (e.g., million genome projects), and new regulations (e.g., for laboratory developed tests). In addition, there are many emerging technologies (e.g., planar arrays, mass spectrometry) that might find even broader application in the future and therefore also disrupt current practice. One interesting source of disruptive technology may prove to be the Qualcomm Tricorder XPrize, currently in its final stages.

  2. Search and Disrupt

    DEFF Research Database (Denmark)

    Ørding Olsen, Anders

    Extant research on external knowledge search and open innovation assumes that collaborators are aligned in their strategic interests towards solving innovation problems. However, disruptive innovation is known to threaten the competitive advantage of incumbent firms, thereby creating a potential...... conflict of interest between these firms and their collaborators. This paper explores the extent to which strategic interests influence joint problem solving in both complementary and disruptive technologies by analyzing the effects of incumbent collaboration. The analysis disentangles inability...... and strategic intent to find that non-incumbents experience suppression of problem solving likelihood within disruptive technologies when incumbent collaborators are not strategically committed. The paper contributes to extant theory by showing the influence of firms’ underlying strategic interests...

  3. Endocrine disrupting chemicals

    DEFF Research Database (Denmark)

    Mandrup, Karen

    suggested as particularly sensitive to endocrine disruption. Mammary gland examination in toxicological studies may be useful for improving knowledge on possible influences of EDCs on human mammary glands and also be useful for detection of endocrine disrupting effects of chemicals as part of safety testing....... To improve knowledge on possible influences of endocrine disrupters on female reproductive system, the effects of EDCs on genital malformations in females and the development of mammary glands were studied in the present project. AIMS: The aims for the studies on male and female mammary gland development...... effects on prepubertal female rat mammary glands were observed at lower levels than those affecting other endpoints studied. CONCLUSION: The present findings in rats suggest that EDCs may affect mammary gland development in women and men, although risk assessment including comparison with exposure...

  4. Coho salmon dependence on intermittent streams.

    Science.gov (United States)

    P.J. Wigington; J.L. Ebersole; M.E. Colvin; S.G. Leibowitz; B. Miller; B. Hansen; H. Lavigne; D. White; J.P. Baker; M.R. Church; J.R. Brooks; M.A. Cairns; J.E. Compton

    2006-01-01

    In this paper, we quantify the contributions of intermittent streams to coho salmon production in an Oregon coastal watershed. We provide estimates of (1) proportion of spawning that occurred in intermittent streams, (2) movement of juveniles into intermittent streams, (3) juvenile survival in intermittent and perennial streams during winter, and (4) relative size of...

  5. Updraft gasification of salmon processing waste

    Science.gov (United States)

    The purpose of this research is to judge the feasibility of gasification for the disposal of waste streams generated through salmon harvesting. Gasification is the process of converting carbonaceous materials into combustible “syngas” in a high temperature (above 700 °C), oxygen deficient environmen...

  6. SCIENCE, POLITICS, AND PACIFIC NORTHWEST SALMON RECOVERY

    Science.gov (United States)

    Throughout the Pacific Northwest, since 1850, all wild salmon runs have declined and some have disappeared. Billions of dollars have been spent in a so-far failed attempt to reverse the long-term decline. Each year, hundreds of millions of dollars continue to be spent in variou...

  7. Pacific Salmon in aquatic and terrestrial ecosystem.

    Science.gov (United States)

    S.M. Gende; R.T. Edwards; M.F. Willson; M.S. Wipfli

    2002-01-01

    almon runs in the Pacific Northwest have been declining for decades, so much so that many runs are threatened or endangered; others have been completely extirpated (Nehlsen et al. 1991). This "salmon crisis" looms large in the public eye, because it has serious and wideranging economic, cultural, and ecological repercussions. Billions of dollars have gone...

  8. Salmon theology: Return to traditional reasoning

    Science.gov (United States)

    Joseph Clair

    2007-01-01

    When beauty and utility are divorced in the loss of wonder, beauty begins to perish. Salmon go extinct. The fragility of beauty is the fragility of wilderness. It does not perish due to weakness but from the generosity and vulnerability that are bound up with its usefulness.

  9. Evaluation of microcirculation in elderly patients with venous trophic ulcers.

    Science.gov (United States)

    Losev, R Z; Burov, Iu A; Mikul'skaia, Ie G; Iakusheva, Ie A

    2005-01-01

    Altogether 112 patients over 50 years of age suffering from varicosity and chronic trophic ulcers of the distal limb segments were examined. The work was based on an analysis of the microcirculatory flow in lower limb tissues (laser Doppler flowmetry, BLF 21 system, Transonic Systems Inc., USA) and on the evaluation of tissue metabolism by measuring partial oxygen and carbon dioxide tension (percutaneous polarography; TCM-3 system, Radiometry Company, Denmark). The postischemic and orthostatic tests were used to assess the functional microcirculatory reserve. The data obtained indicate local tissue hypoxia in elderly patients with venous trophic ulcers associated with an increase of the basal flow only in the lower third of the leg. Venous trophic ulcers are marked by a significant reduction of partial oxygen tension in the tissues adjacent to the area of trophic ulcers to 4.3+/-0.5 mm Hg on the average in the presence of the low functional microcirculatory reserve. Local tissue hypoxia in the area of trophic ulcers, which develops despite an increase of blood inflow to the microcirculatory bed evidences inhibition of tissue flow and activation of the arterio-venular bypasses. The results obtained in the course of the study allow to optimize the treatment policy in elderly patients suffering from venous trophic ulcers. In addition to the measures lowering venous hypertension, the treatment should include correction of microcirculatory disorders, which is to be carried out in the pre- and postoperative periods.

  10. Interruptions disrupt reading comprehension.

    Science.gov (United States)

    Foroughi, Cyrus K; Werner, Nicole E; Barragán, Daniela; Boehm-Davis, Deborah A

    2015-06-01

    Previous research suggests that being interrupted while reading a text does not disrupt the later recognition or recall of information from that text. This research is used as support for Ericsson and Kintsch's (1995) long-term working memory (LT-WM) theory, which posits that disruptions while reading (e.g., interruptions) do not impair subsequent text comprehension. However, to fully comprehend a text, individuals may need to do more than recognize or recall information that has been presented in the text at a later time. Reading comprehension often requires individuals to connect and synthesize information across a text (e.g., successfully identifying complex topics such as themes and tones) and not just make a familiarity-based decision (i.e., recognition). The goal for this study was to determine whether interruptions while reading disrupt reading comprehension when the questions assessing comprehension require participants to connect and synthesize information across the passage. In Experiment 1, interruptions disrupted reading comprehension. In Experiment 2, interruptions disrupted reading comprehension but not recognition of information from the text. In Experiment 3, the addition of a 15-s time-out prior to the interruption successfully removed these negative effects. These data suggest that the time it takes to process the information needed to successfully comprehend text when reading is greater than that required for recognition. Any interference (e.g., an interruption) that occurs during the comprehension process may disrupt reading comprehension. This evidence supports the need for transient activation of information in working memory for successful text comprehension and does not support LT-WM theory. (c) 2015 APA, all rights reserved).

  11. Alcohol disrupts sleep homeostasis

    Science.gov (United States)

    Thakkar, Mahesh M.; Sharma, Rishi; Sahota, Pradeep

    2014-01-01

    Alcohol is a potent somnogen and one of the most commonly used “over the counter” sleep aids. In healthy non-alcoholics, acute alcohol decreases sleep latency, consolidates and increases the quality (delta power) and quantity of NREM sleep during the first half of the night. However, sleep is disrupted during the second half. Alcoholics, both during drinking periods and during abstinences, suffer from a multitude of sleep disruptions manifested by profound insomnia, excessive daytime sleepiness, and altered sleep architecture. Furthermore, subjective and objective indicators of sleep disturbances are predictors of relapse. Finally, within the USA, it is estimated that societal costs of alcohol-related sleep disorders exceeds $18 billion. Thus, although alcohol-associated sleep problems have significant economic and clinical consequences, very little is known about how and where alcohol acts to affect sleep. In this review, we have described our attempts to understand how and where alcohol acts to affect sleep. We have conducted a series of experiments using two different species, rats and mice, as animal models, and a combination of multi-disciplinary experimental methodologies to examine and understand anatomical and cellular substrates mediating the effects of acute and chronic alcohol exposure on sleep-wakefulness. The results of our studies suggest that the sleep-promoting effects of alcohol may be mediated via alcohol’s action on the mediators of sleep homeostasis: adenosine (AD) and the wake-promoting cholinergic neurons of the basal forebrain (BF). Alcohol, via its action on AD uptake, increases extracellular AD resulting in the inhibition of BF wake-promoting neurons. Lesions of the BF cholinergic neurons or blockade of AD A1 receptors results in attenuation of alcohol-induced sleep promotion, suggesting that AD and BF cholinergic neurons are critical for sleep-promoting effects of alcohol. Since binge alcohol consumption is a highly prevalent pattern

  12. Juvenile salmon usage of the Skeena River estuary.

    Directory of Open Access Journals (Sweden)

    Charmaine Carr-Harris

    Full Text Available Migratory salmon transit estuary habitats on their way out to the ocean but this phase of their life cycle is more poorly understood than other phases. The estuaries of large river systems in particular may support many populations and several species of salmon that originate from throughout the upstream river. The Skeena River of British Columbia, Canada, is a large river system with high salmon population- and species-level diversity. The estuary of the Skeena River is under pressure from industrial development, with two gas liquefaction terminals and a potash loading facility in various stages of environmental review processes, providing motivation for understanding the usage of the estuary by juvenile salmon. We conducted a juvenile salmonid sampling program throughout the Skeena River estuary in 2007 and 2013 to investigate the spatial and temporal distribution of different species and populations of salmon. We captured six species of juvenile anadromous salmonids throughout the estuary in both years, and found that areas proposed for development support some of the highest abundances of some species of salmon. Specifically, the highest abundances of sockeye (both years, Chinook in 2007, and coho salmon in 2013 were captured in areas proposed for development. For example, juvenile sockeye salmon were 2-8 times more abundant in the proposed development areas. Genetic stock assignment demonstrated that the Chinook salmon and most of the sockeye salmon that were captured originated from throughout the Skeena watershed, while some sockeye salmon came from the Nass, Stikine, Southeast Alaska, and coastal systems on the northern and central coasts of British Columbia. These fish support extensive commercial, recreational, and First Nations fisheries throughout the Skeena River and beyond. Our results demonstrate that estuary habitats integrate species and population diversity of salmon, and that if proposed development negatively affects the

  13. Pacific salmon effects on stream ecosystems: a quantitative synthesis.

    Science.gov (United States)

    Janetski, David J; Chaloner, Dominic T; Tiegs, Scott D; Lamberti, Gary A

    2009-03-01

    Pacific salmon (Oncorhynchus spp.) disturb sediments and fertilize streams with marine-derived nutrients during their annual spawning runs, leading researchers to classify these fish as ecosystem engineers and providers of resource subsidies. While these processes strongly influence the structure and function of salmon streams, the magnitude of salmon influence varies widely across studies. Here, we use meta-analysis to evaluate potential sources of variability among studies in stream ecosystem responses to salmon. Results obtained from 37 publications that collectively included 79 streams revealed positive, but highly inconsistent, overall effects of salmon on dissolved nutrients, sediment biofilm, macroinvertebrates, resident fish, and isotopic enrichment. Variation in these response variables was commonly influenced by salmon biomass, stream discharge, sediment size, and whether studies used artificial carcass treatments or observed a natural spawning run. Dissolved nutrients were positively related to salmon biomass per unit discharge, and the slope of the relationship for natural runs was five to ten times higher than for carcass additions. Mean effects on ammonium and phosphorus were also greater for natural runs than carcass additions, an effect attributable to excretion by live salmon. In contrast, we observed larger positive effects on benthic macroinvertebrates for carcass additions than for natural runs, likely because disturbance by live salmon was absent. Furthermore, benthic macroinvertebrates and biofilm associated with small sediments (salmon while those associated with large sediments (>32 mm) showed a positive response. This comprehensive analysis is the first to quantitatively identify environmental and methodological variables that influence the observed effects of salmon. Identifying sources of variation in salmon-stream interactions is a critical step toward understanding why engineering and subsidy effects vary so dramatically over space and

  14. Differential use of salmon by vertebrate consumers: implications for conservation

    Directory of Open Access Journals (Sweden)

    Taal Levi

    2015-08-01

    Full Text Available Salmon and other anadromous fish are consumed by vertebrates with distinct life history strategies to capitalize on this ephemeral pulse of resource availability. Depending on the timing of salmon arrival, this resource may be in surplus to the needs of vertebrate consumers if, for instance, their populations are limited by food availability during other times of year. However, the life history of some consumers enables more efficient exploitation of these ephemeral resources. Bears can deposit fat and then hibernate to avoid winter food scarcity, and highly mobile consumers such as eagles, gulls, and other birds can migrate to access asynchronous pulses of salmon availability. We used camera traps on pink, chum, and sockeye salmon spawning grounds with various run times and stream morphologies, and on individual salmon carcasses, to discern potentially different use patterns among consumers. Wildlife use of salmon was highly heterogeneous. Ravens were the only avian consumer that fed heavily on pink salmon in small streams. Eagles and gulls did not feed on early pink salmon runs in streams, and only moderately at early sockeye runs, but were the dominant consumers at late chum salmon runs, particularly on expansive river flats. Brown bears used all salmon resources far more than other terrestrial vertebrates. Notably, black bears were not observed on salmon spawning grounds despite being the most frequently observed vertebrate on roads and trails. From a conservation and management perspective, all salmon species and stream morphologies are used extensively by bears, but salmon spawning late in the year are disproportionately important to eagles and other highly mobile species that are seasonally limited by winter food availability.

  15. A trophic position model of pelagic food webs: Impact on contaminant bioaccumulation in lake trout

    Energy Technology Data Exchange (ETDEWEB)

    Zanden, M.J.V.; Rasmussen, J.B. [McGill Univ., Montreal, Quebec (Canada)

    1996-11-01

    To test how well use of discrete trophic levels represents pelagic trophic structure, dietary data from > 200 lake trout and pelagic forage fish populations was compiled and calculated a continuous (fractional) measure of trophic position for each population. Lake trout trophic position, which ranged from 3.0 to 4.6, explained 85% of the between-lake variability in mean PCB levels in lake trout muscle tissue, providing a significant improvement over the use of discrete trophic levels as a predictor of contaminant levels. Having demonstrated the utility of trophic position, a generalized {open_quotes}trophic position model{close_quotes} of lake trout food webs was developed. This approach eliminates minor trophic linkages, calculates a fractional measure of each species` trophic position, and aggregates species of similar trophic position into trophic guilds. This {open_quotes}realized{close_quotes} model represents trophic structure in terms of mass transfer and accounts for the complexity and omnivory that characterize aquatic food webs. In our trophic position model, smelt (a species of pelagic forage fish) were designated a trophic guild separate from other pelagic forage fish, due to their elevated trophic position. Separate consideration of smelt was supported by elevated lake trout trophic position, PCB, and Hg levels in lakes containing smelt. Consideration of omnivory caused biomagnification factors (BMFs) to be many times higher than BMFs that ignored omnivory. These omnivory-corrected BMF estimates appeared to be more consistent with values calculated using stable nitrogen isotopes ({delta}{sup 15}N), an alternative continuous measure of trophic position. {delta}{sup 15}N, an alternative continuous measure of trophic position. {delta}{sup 15}N provided trophic position estimates that generally corresponded with our diet-derived estimates. 186 refs., 7 figs., 3 tabs.

  16. Sustainable Disruption Management

    DEFF Research Database (Denmark)

    Vaaben, Bo Valdemar

    in the same way, when operation is disrupted. Never the less, we may recall that the Suez Canal was closed due to riots in Egypt, that the fuel price was impacted by threats of closing of the Strait of Hormuz, and we do from time to time hear about acts of piracy outside the coast of Somalia. All...

  17. Concentrations of trace elements in Pacific and Atlantic salmon

    Science.gov (United States)

    Khristoforova, N. K.; Tsygankov, V. Yu.; Boyarova, M. D.; Lukyanova, O. N.

    2015-09-01

    Concentrations of Hg, As, Cd, Pb, Zn, and Cu were analyzed in the two most abundant species of Pacific salmon, chum and pink salmon, caught in the Kuril Islands at the end of July, 2013. The concentrations of toxic elements (Hg, As, Pb, Cd) in males and females of these species are below the maximum permissible concentrations for seafood. It was found that farmed filleted Atlantic salmon are dominated by Zn and Cu, while muscles of wild salmon are dominated by Pb. Observed differences are obviously related to peculiar environmental geochemical conditions: anthropogenic impact for Atlantic salmon grown in coastal waters and the influence of the natural factors volcanism and upwelling for wild salmon from the Kuril waters.

  18. Coho Salmon Master Plan, Clearwater River Basin.

    Energy Technology Data Exchange (ETDEWEB)

    Nez Perce Tribe; FishPro

    2004-10-01

    The Nez Perce Tribe has a desire and a goal to reintroduce and restore coho salmon to the Clearwater River Subbasin at levels of abundance and productivity sufficient to support sustainable runs and annual harvest. Consistent with the Clearwater Subbasin Plan (EcoVista 2003), the Nez Perce Tribe envisions developing an annual escapement of 14,000 coho salmon to the Clearwater River Subbasin. In 1994, the Nez Perce Tribe began coho reintroduction by securing eggs through U.S. v. Oregon; by 1998 this agreement provided an annual transfer of 550,000 coho salmon smolts from lower Columbia River hatchery facilities for release in the Clearwater River Subbasin. In 1998, the Northwest Power and Conservation Council authorized the Bonneville Power Administration to fund the development of a Master Plan to guide this reintroduction effort. This Master Plan describes the results of experimental releases of coho salmon in the Clearwater River Subbasin, which have been ongoing since 1995. These data are combined with results of recent coho reintroduction efforts by the Yakama Nation, general coho life history information, and historical information regarding the distribution and life history of Snake River coho salmon. This information is used to assess a number of alternative strategies aimed at restoring coho salmon to historical habitats in the Clearwater River subbasin. These data suggest that there is a high probability that coho salmon can be restored to the Clearwater River subbasin. In addition, the data also suggest that the re-establishment of coho salmon could be substantially aided by: (1) the construction of low-tech acclimation facilities; (2) the establishment of a 'localized' stock of coho salmon; and (3) the construction of hatchery facilities to provide a source of juvenile coho salmon for future supplementation activities. The Nez Perce Tribe recognizes that there are factors which may limit the success of coho reintroduction. As a result of these

  19. A stage-structured Bayesian hierarchical model for salmon lice populations at individual salmon farms – Estimated from multiple farm data sets

    OpenAIRE

    Aldrin, Magne Tommy; Huseby, Ragnar Bang; Stien, Audun; Grøntvedt, Randi Nygaard; Viljugrein, Hildegunn; Jansen, Peder A

    2017-01-01

    Salmon farming has become a prosperous international industry over the last decades. Along with growth in the production farmed salmon, however, an increasing threat by pathogens has emerged. Of special concern is the propagation and spread of the salmon louse, Lepeophtheirus salmonis. To gain insight into this parasite’s population dynamics in large scale salmon farming system, we present a fully mechanistic stage-structured population model for the salmon louse, also allowing for complexiti...

  20. Reconnecting Social and Ecological Resilience in Salmon Ecosystems

    Directory of Open Access Journals (Sweden)

    Daniel L. Bottom

    2009-06-01

    Full Text Available Fishery management programs designed to control Pacific salmon (Oncorhynchus spp. for optimum production have failed to prevent widespread fish population decline and have caused greater uncertainty for salmon, their ecosystems, and the people who depend upon them. In this special feature introduction, we explore several key attributes of ecosystem resilience that have been overlooked by traditional salmon management approaches. The dynamics of salmon ecosystems involve social-ecological interactions across multiple scales that create difficult mismatches with the many jurisdictions that manage fisheries and other natural resources. Of particular importance to ecosystem resilience are large-scale shifts in oceanic and climatic regimes or in global economic conditions that unpredictably alter social and ecological systems. Past management actions that did not account for such changes have undermined salmon population resilience and increased the risk of irreversible regime shifts in salmon ecosystems. Because salmon convey important provisioning, cultural, and supporting services to their local watersheds, widespread population decline has undermined both human well-being and ecosystem resilience. Strengthening resilience will require expanding habitat opportunities for salmon populations to express their maximum life-history variation. Such actions also may benefit the "response diversity" of local communities by expanding the opportunities for people to express diverse social and economic values. Reestablishing social-ecological connections in salmon ecosystems will provide important ecosystem services, including those that depend on clean water, ample stream flows, functional wetlands and floodplains, intact riparian systems, and abundant fish populations.

  1. Diphyllobothrium latum infection after eating domestic salmon flesh

    Science.gov (United States)

    Lee, Kyung Won; Suhk, Hyo-Chung; Shin, Ho-Jun; Jung, Suk-Yul; Han, Eun-Taek; Chai, Jong-Yil

    2001-01-01

    Diphyllobothrium latum infection in human is not common in Korea and only thirty seven cases have been reported since 1921. We report two cases of fish tapeworm infection after Ingestion of raw cherry salmon (Oncorhynchus masou) caught in the domestic river. Among four family members who ate together raw salmon flesh six months ago, just two, mother and daughter, were infected. It is our expectation that the salmon associated tapeworm infections would be enlisted as one of the major parasitic problems with the growing consumption of salmon in Korea. PMID:11775333

  2. A global assessment of salmon aquaculture impacts on wild salmonids.

    Directory of Open Access Journals (Sweden)

    Jennifer S Ford

    2008-02-01

    Full Text Available Since the late 1980s, wild salmon catch and abundance have declined dramatically in the North Atlantic and in much of the northeastern Pacific south of Alaska. In these areas, there has been a concomitant increase in the production of farmed salmon. Previous studies have shown negative impacts on wild salmonids, but these results have been difficult to translate into predictions of change in wild population survival and abundance. We compared marine survival of salmonids in areas with salmon farming to adjacent areas without farms in Scotland, Ireland, Atlantic Canada, and Pacific Canada to estimate changes in marine survival concurrent with the growth of salmon aquaculture. Through a meta-analysis of existing data, we show a reduction in survival or abundance of Atlantic salmon; sea trout; and pink, chum, and coho salmon in association with increased production of farmed salmon. In many cases, these reductions in survival or abundance are greater than 50%. Meta-analytic estimates of the mean effect are significant and negative, suggesting that salmon farming has reduced survival of wild salmon and trout in many populations and countries.

  3. Deep water, an effect on the temperature for the management of caligodosis in the Atlantic salmon (Salmon salar)

    OpenAIRE

    Riquelme, Roberto; Laboratorio de Biología Celular Aplicada, Núcleo de investigación en Producción Alimentaria-NIPA, Facultad de Recursos Naturales, Universidad Católica de Temuco, Temuco; Olivares-Ferretti, Pamela; Laboratorio de Biología Celular Aplicada, Núcleo de investigación en Producción Alimentaria-NIPA, Facultad de Recursos Naturales, Universidad Católica de Temuco, Temuco; Fonseca-Salamanca, Flery; Laboratorio de Inmuno Parasitología Molecular, Centro de Excelencia en Medicina Traslacional, Departamento de Ciencias Preclínicas, Universidad de La Frontera, Temuco; Parodi, Jorge; Laboratorio de Biología Celular Aplicada, Núcleo de investigación en Producción Alimentaria-NIPA, Facultad de Recursos Naturales, Universidad Católica de Temuco, Temuco

    2017-01-01

    Salmon farming is one of the pillars of the Chilean economy but due the emerging of many diseases, including the ecto-parasitism caused by Caligus rogercresseyi, the salmon industry has decreased their production indices. Based on that, alternative rearing systems are being evaluated for salmon cultivation, one of them fish farming in deep water, where the temperature is lower than the temperature of the surface, as C. rogercresseyi is a parasite whose life cycle is water temperature dependen...

  4. Trophic interaction modifications: an empirical and theoretical framework.

    Science.gov (United States)

    Terry, J Christopher D; Morris, Rebecca J; Bonsall, Michael B

    2017-10-01

    Consumer-resource interactions are often influenced by other species in the community. At present these 'trophic interaction modifications' are rarely included in ecological models despite demonstrations that they can drive system dynamics. Here, we advocate and extend an approach that has the potential to unite and represent this key group of non-trophic interactions by emphasising the change to trophic interactions induced by modifying species. We highlight the opportunities this approach brings in comparison to frameworks that coerce trophic interaction modifications into pairwise relationships. To establish common frames of reference and explore the value of the approach, we set out a range of metrics for the 'strength' of an interaction modification which incorporate increasing levels of contextual information about the system. Through demonstrations in three-species model systems, we establish that these metrics capture complimentary aspects of interaction modifications. We show how the approach can be used in a range of empirical contexts; we identify as specific gaps in current understanding experiments with multiple levels of modifier species and the distributions of modifications in networks. The trophic interaction modification approach we propose can motivate and unite empirical and theoretical studies of system dynamics, providing a route to confront ecological complexity. © 2017 The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.

  5. Shift in trophic level of Mediterranean mariculture species.

    Science.gov (United States)

    Tsikliras, Athanassios C; Stergiou, Konstantinos I; Adamopoulos, Nikolaos; Pauly, Daniel; Mente, Eleni

    2014-08-01

    The mean trophic level of the farmed fish species in the Mediterranean has been increasing. We examined the farming-up hypothesis (i.e., the increase in the production of high-trophic-level species) in the Mediterranean by determining the trophic level of the aquafeeds (i.e., what the fish are fed) of 5 species of farmed marine fishes: common dentex (Dentex dentex), common pandora (Pagellus erythrinus), European seabass (Dicentrarchus labrax), gilthead seabream (Sparus aurata), and red porgy (Pagrus sp.). The mean trophic level of aquafeed used in mariculture from 1950 to 2011 was higher (3.93) than the prey farmed fish consume in the wild (3.72) and increased at a faster rate (0.48/decade) compared with that based on their diets in the wild (0.43/decade). Future expected replacement of the fishmeal and oil in aquafeeds by plant materials may reverse the farming-up trend, although there are a number of concerns regarding operational, nutritional, environmental, and economic issues. The farming-up reversal can be achieved in an ecologically friendly manner by facilitating the mariculture of low-trophic-level fishes and by promoting high efficiency in the use of living marine resources in aquafeeds. © 2014 Society for Conservation Biology.

  6. Modeling (137)Cs bioaccumulation in the salmon-resident killer whale food web of the Northeastern Pacific following the Fukushima Nuclear Accident.

    Science.gov (United States)

    Alava, Juan José; Gobas, Frank A P C

    2016-02-15

    To track the long term bioaccumulation of (137)Cs in marine organisms off the Pacific Northwest coast of Canada, we developed a time dependent bioaccumulation model for (137)Cs in a marine mammalian food web that included fish-eating resident killer whales. The model outcomes show that (137)Cs can be expected to gradually bioaccumulate in the food web over time as demonstrated by the increase of the apparent trophic magnification factor of (137)Cs, ranging from 0.76 after 1 month of exposure to 2.0 following 30 years of exposure. (137)Cs bioaccumulation is driven by relatively rapid dietary uptake rates, moderate depuration rates in lower trophic level organisms and slow elimination rates in high trophic level organisms. Model estimates of the (137)Cs activity in species of the food web, based on current measurements and forecasts of (137)Cs activities in oceanic waters and sediments off the Canadian Pacific Northwest, indicate that the long term (137)Cs activities in fish species including Pacific herring, wild Pacific salmon, sablefish and halibut will remain well below the current (137)Cs-Canada Action Level for consumption (1000 Bq/kg) following a nuclear emergency. Killer whales and Pacific salmon are expected to exhibit the largest long term (137)Cs activities and may be good sentinels for monitoring (137)Cs in the region. Assessment of the long term consequences of (137)Cs releases from the Fukushima aftermath should consider the extent of ecological magnification in addition to ocean dilution. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Vocally disruptive behavior.

    Science.gov (United States)

    White, M K; Kaas, M J; Richie, M F

    1996-11-01

    Vocally disruptive behavior (VDB) is intelligible or unintelligible noise making that may be goal-directed or purposeless. VDB can be conceptualized as a cyclic phenomenon. VDB has been linked to cognitive impairment, poor sleep, requiring assistance with ADLs, and being at high risk for falling. General nursing interventions for VDB include remaining calm, using gentle touch, creating a familiar, home-like environment, and using diversions during ADLs.

  8. Alteration of thyroid hormone concentrations in juvenile Chinook salmon (Oncorhynchus tshawytscha) exposed to polybrominated diphenyl ethers, BDE-47 and BDE-99.

    Science.gov (United States)

    Arkoosh, Mary R; Van Gaest, Ahna L; Strickland, Stacy A; Hutchinson, Greg P; Krupkin, Alex B; Dietrich, Joseph P

    2017-03-01

    Polybrominated diphenyl ethers (PBDEs) have been used as flame-retardants in consumer products and are currently detected in salmon globally. The two most predominant PBDE congeners found in salmon are BDE-47 (2,2',4,4'-tetrabromodiphenyl ether) and BDE-99 (2,2',4,4',5-pentabromodiphenyl ether). In the present study, groups of juvenile Pacific Chinook salmon were fed five environmentally relevant concentrations of either BDE-47 (0.3-552 ng total PBDEs/g food), BDE-99 (0.3-580 ng total PBDEs/g food), or nearly equal mixtures of both congeners (0.7-690 ng total PBDEs/g food) for 39-40 days. The concentrations of circulating total thyroid hormones, thyroxine (T4) and 3,5,3'-triiodothyronine (T3), were measured using a hormone-specific time-resolved fluoroimmunoassay to determine if PBDE exposure disrupts the hypothalamic-pituitary-thyroid endocrine axis. The concentrations of both circulating T4 and T3 were altered in juvenile salmon by dietary uptake of BDE-99. Exposure to BDE-47 did not alter either T3 or T4 circulating hormone concentrations. However, exposure to a mixture of BDE-47 and BDE-99 reduced T3 in fish with lower concentrations of total whole body PBDEs than with either congener alone at equivalent PBDE whole body concentrations. Accordingly, the disruption of PBDEs on circulating thyroid hormone concentrations has the potential to impact a number of critical functions in juvenile salmon including growth, parr-smolt transformation, and immunological processes. Published by Elsevier Ltd.

  9. Import risk assessment for salmon meat.

    Science.gov (United States)

    Beers, P T; Wilson, D W

    1993-12-01

    The authors discuss the risk assessment currently being conducted by the Australian Quarantine and Inspection Service (AQIS) on the importation of salmon products. AQIS conducted a public consultation on the proposal, in line with Australian Government policy on transparency and accountability in the quarantine decision-making process. The authors examine the factors which should be taken into account in the assessment of the risk associated with the importation of such products, and note the difficulties encountered with the epidemiology of fish diseases.

  10. Bioaccumulation and trophic dilution of human pharmaceuticals across trophic positions of an effluent-dependent wadeable stream.

    Science.gov (United States)

    Du, Bowen; Haddad, Samuel P; Luek, Andreas; Scott, W Casan; Saari, Gavin N; Kristofco, Lauren A; Connors, Kristin A; Rash, Christopher; Rasmussen, Joseph B; Chambliss, C Kevin; Brooks, Bryan W

    2014-11-19

    Though pharmaceuticals are increasingly observed in a variety of organisms from coastal and inland aquatic systems, trophic transfer of pharmaceuticals in aquatic food webs have not been reported. In this study, bioaccumulation of select pharmaceuticals was investigated in a lower order effluent-dependent stream in central Texas, USA, using isotope dilution liquid chromatography-tandem mass spectrometry (MS). A fish plasma model, initially developed from laboratory studies, was tested to examine observed versus predicted internal dose of select pharmaceuticals. Pharmaceuticals accumulated to higher concentrations in invertebrates relative to fish; elevated concentrations of the antidepressant sertraline and its primary metabolite desmethylsertraline were observed in the Asian clam, Corbicula fluminea, and two unionid mussel species. Trophic positions were determined from stable isotopes (δ(15)N and δ(13)C) collected by isotope ratio-MS; a Bayesian mixing model was then used to estimate diet contributions towards top fish predators. Because diphenhydramine and carbamazepine were the only target compounds detected in all species examined, trophic magnification factors (TMFs) were derived to evaluate potential trophic transfer of both compounds. TMFs for diphenhydramine (0.38) and carbamazepine (1.17) indicated neither compound experienced trophic magnification, which suggests that inhalational and not dietary exposure represented the primary route of uptake by fish in this effluent-dependent stream. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  11. Fish Reproduction Is Disrupted upon Lifelong Exposure to Environmental PAHs Fractions Revealing Different Modes of Action

    Directory of Open Access Journals (Sweden)

    Caroline Vignet

    2016-10-01

    Full Text Available Polycyclic aromatic hydrocarbons (PAHs constitute a large family of organic pollutants emitted in the environment as complex mixtures, the compositions of which depend on origin. Among a wide range of physiological defects, PAHs are suspected to be involved in disruption of reproduction. In an aquatic environment, the trophic route is an important source of chronic exposure to PAHs. Here, we performed trophic exposure of zebrafish to three fractions of different origin, one pyrolytic and two petrogenic. Produced diets contained PAHs at environmental concentrations. Reproductive traits were analyzed at individual, tissue and molecular levels. Reproductive success and cumulative eggs number were disrupted after exposure to all three fractions, albeit to various extents depending on the fraction and concentrations. Histological analyses revealed ovary maturation defects after exposure to all three fractions as well as degeneration after exposure to a pyrolytic fraction. In testis, hypoplasia was observed after exposure to petrogenic fractions. Genes expression analysis in gonads has allowed us to establish common pathways such as endocrine disruption or differentiation/maturation defects. Taken altogether, these results indicate that PAHs can indeed disrupt fish reproduction and that different fractions trigger different pathways resulting in different effects.

  12. DANUBE SALMON (HUCHO HUCHO L.. THEMATIC BIBLIOGRAPHY

    Directory of Open Access Journals (Sweden)

    I. Hrytsynyak

    2015-09-01

    Full Text Available Purpose. Creating of the thematic bibliographic list of publications dedicated to ecological and zoogeographical, morphological and biological, physiological, biochemical and genetic characteristics of the Danube salmon, as well as to its cultivation in Ukraine and abroad. Methodology. In the process of systematic search complete and selective methods were applied. The bibliographic core have been formed by the literature from the fund of scientific library of the Institute of Fisheries NAAS. Findings. There was composed the thematic list of publications in a quantity of 100 sources, containing characteristics of Danube salmon as representative of salmonids. Literary sources was arranged in alphabetical order by author or title, and described according to DSTU 7.1:2006 «System of standards on information, librarianship and publishing. Bibliographic entry. Bibliographic description. General requirements and rules», as well as in accordance with the requirements of APA style – international standard of references. Practical value. The list may be useful for scientists, practitioners, students, whose area of interests covers the questions of breeding, and researching of the salmon biological features.

  13. Estimate of the trophic status of subarctic Imandra Lake

    Directory of Open Access Journals (Sweden)

    Terent'eva I. A.

    2017-03-01

    Full Text Available The object of study is Imandra Lake – the largest reservoir of the Murmansk region. The lake is being influenced by the long-term and multi-factorial activities of mining and ore processing industries, air pollution and energetics. Moreover, the drain of municipal sewage from the large settlements situated on the lake's watershed makes a serious contribution to water pollution. As a result the lake has accumulated a significant amount of pollutants and nutrients that resulted currently in an increase of the toxic load on the lake system. One of the main ecological problems also is the intensification of the anthropogenic eutrophication processes. The aim of this study is to evaluate the current trophic status of Imandra Lake using the trophic index (TSI with the average annual values of the parameters: chlorophyll, total nitrogen, total phosphorus, and total organic carbon and to find the dynamics of these parameters' changes during more than 20-year period. The study of the trophic status of Imandra Lake has been performed for the period 1991–2013 yrs. using the trophic state index developed by Carlson, Kratzer and Bresonik, Dunalska. According to the calculated values of the indexes Bolshaja Imandra Lake corresponds to eutrophic-mesotrophic trophic status, Yokostrovskaya Imandra Lake could be described as mesotrophic. Babinskaja Imandra Lake that subjected to essential nutrient loading is close to the oligotrophic trophic status. However, some parts of Babinskaja Imandra Lake refer to the mesotrophic state due to influence of industrial, household and heated water of the Kola atomic power station. Thus, this part of Imadra Lake could be considered as a meso-oligotrophic status. It has been established that currently nitrogen is a limiting factor for development of algae in Imandra Lake. Based on the mathematical Vollenweider model the critical phosphorus loading values to control such an important nutrient element as phosphorus have been

  14. Phenological sensitivity to climate across taxa and trophic levels

    DEFF Research Database (Denmark)

    Thackeray, Stephen J.; Henrys, Peter; Hemming, Deborah

    2016-01-01

    Differences in phenological responses to climate change among species can desynchronise ecological interactions and thereby threaten ecosystem function. To assess these threats, we must quantify the relative impact of climate change on species at different trophic levels. Here, we apply a Climate...... of phenological events could change more for primary consumers than for species in other trophic levels (6.2 versus 2.5–2.9 days earlier on average), with substantial taxonomic variation (1.1–14.8 days earlier on average)....

  15. Salmon Site Remedial Investigation Report, Main Body

    Energy Technology Data Exchange (ETDEWEB)

    US DOE/NV

    1999-09-01

    This Salmon Site Remedial Investigation Report provides the results of activities initiated by the U.S. Department of Energy (DOE) to determine if contamination at the Salmon Site poses a current or future risk to human health and the environment. These results were used to develop and evaluate a range of risk-based remedial alternatives. Located in Lamar County, Mississippi, the Salmon Site was used by the U.S. Atomic Energy Commission (predecessor to the DOE) between 1964 and 1970 for two nuclear and two gas explosions conducted deep underground in a salt dome. The testing resulted in the release of radionuclides into the salt dome. During reentry drilling and other site activities, liquid and solid wastes containing radioactivity were generated resulting in surface soil and groundwater contamination. Most of the waste and contaminated soil and water were disposed of in 1993 during site restoration either in the cavities left by the tests or in an injection well. Other radioactive wastes were transported to the Nevada Test Site for disposal. Nonradioactive wastes were disposed of in pits at the site and capped with clean soil and graded. The preliminary investigation showed residual contamination in the Surface Ground Zero mud pits below the water table. Remedial investigations results concluded the contaminant concentrations detected present no significant risk to existing and/or future land users, if surface institutional controls and subsurface restrictions are maintained. Recent sampling results determined no significant contamination in the surface or shallow subsurface. The test cavity resulting from the experiments is contaminated and cannot be economically remediated with existing technologies. The ecological sampling did not detect biological uptake of contaminants in the plants or animals sampled. Based on the current use of the Salmon Site, the following remedial actions were identified to protect both human health and the environment: (1) the

  16. Salmon Site Remedial Investigation Report, Exhibit 5

    Energy Technology Data Exchange (ETDEWEB)

    USDOE/NV

    1999-09-01

    This Salmon Site Remedial Investigation Report provides the results of activities initiated by the U.S. Department of Energy (DOE) to determine if contamination at the Salmon Site poses a current or future risk to human health and the environment. These results were used to develop and evaluate a range of risk-based remedial alternatives. Located in Lamar County, Mississippi, the Salmon Site was used by the U.S. Atomic Energy Commission (predecessor to the DOE) between 1964 and 1970 for two nuclear and two gas explosions conducted deep underground in a salt dome. The testing resulted in the release of radionuclides into the salt dome. During reentry drilling and other site activities, liquid and solid wastes containing radioactivity were generated resulting in surface soil and groundwater contamination. Most of the waste and contaminated soil and water were disposed of in 1993 during site restoration either in the cavities left by the tests or in an injection well. Other radioactive wastes were transported to the Nevada Test Site for disposal. Nonradioactive wastes were disposed of in pits at the site and capped with clean soil and graded. The preliminary investigation showed residual contamination in the Surface Ground Zero mud pits below the water table. Remedial investigations results concluded the contaminant concentrations detected present no significant risk to existing and/or future land users, if surface institutional controls and subsurface restrictions are maintained. Recent sampling results determined no significant contamination in the surface or shallow subsurface. The test cavity resulting from the experiments is contaminated and cannot be economically remediated with existing technologies. The ecological sampling did not detect biological uptake of contaminants in the plants or animals sampled. Based on the current use of the Salmon Site, the following remedial actions were identified to protect both human health and the environment: (1) the

  17. Salmon Site Remedial Investigation Report, Exhibit 2

    Energy Technology Data Exchange (ETDEWEB)

    USDOE NV

    1999-09-01

    This Salmon Site Remedial Investigation Report provides the results of activities initiated by the U.S. Department of Energy (DOE) to determine if contamination at the Salmon Site poses a current or future risk to human health and the environment. These results were used to develop and evaluate a range of risk-based remedial alternatives. Located in Lamar County, Mississippi, the Salmon Site was used by the U.S. Atomic Energy Commission (predecessor to the DOE) between 1964 and 1970 for two nuclear and two gas explosions conducted deep underground in a salt dome. The testing resulted in the release of radionuclides into the salt dome. During reentry drilling and other site activities, liquid and solid wastes containing radioactivity were generated resulting in surface soil and groundwater contamination. Most of the waste and contaminated soil and water were disposed of in 1993 during site restoration either in the cavities left by the tests or in an injection well. Other radioactive wastes were transported to the Nevada Test Site for disposal. Nonradioactive wastes were disposed of in pits at the site and capped with clean soil and graded. The preliminary investigation showed residual contamination in the Surface Ground Zero mud pits below the water table. Remedial investigations results concluded the contaminant concentrations detected present no significant risk to existing and/or future land users, if surface institutional controls and subsurface restrictions are maintained. Recent sampling results determined no significant contamination in the surface or shallow subsurface. The test cavity resulting from the experiments is contaminated and cannot be economically remediated with existing technologies. The ecological sampling did not detect biological uptake of contaminants in the plants or animals sampled. Based on the current use of the Salmon Site, the following remedial actions were identified to protect both human health and the environment: (1) the

  18. Can intraspecific competition drive disruptive selection? An experimental test in natural populations of sticklebacks.

    Science.gov (United States)

    Bolnick, Daniel I

    2004-03-01

    Theory suggests that frequency-dependent resource competition will disproportionately impact the most common phenotypes in a population. The resulting disruptive selection forms the driving force behind evolutionary models of niche diversification, character release, ecological sexual dimorphism, resource polymorphism, and sympatric speciation. However, there is little empirical support for the idea that intraspecific competition generates disruptive selection. This paper presents a test of this theory, using natural populations of the three-spine stickleback, Gasterosteus aculeatus. Sticklebacks exhibit substantial individual specialization associated with phenotypic variation and so are likely to experience frequency-dependent competition and hence disruptive selection. Using body size and relative gonad mass as indirect measures of potential fecundity and hence fitness, I show that an important aspect of trophic morphology, gill raker length, is subject to disruptive selection in one of two natural lake populations. To test whether this apparent disruptive selection could have been caused by competition, I manipulated population densities in pairs of large enclosures in each of five lakes. In each lake I removed fish from one enclosure and added them to the other to create paired low- and high-population-density treatments with natural phenotype distributions. Again using indirect measures of fitness, disruptive selection was consistently stronger in high-density than low-density enclosures. These results support long-standing theoretical arguments that intraspecific competition drives disruptive selection and thus may be an important causal agent in the evolution of ecological variation.

  19. Trophic transfer potential of aluminium oxide nanoparticles using representative primary producer (Chlorella ellipsoides) and a primary consumer (Ceriodaphnia dubia)

    Energy Technology Data Exchange (ETDEWEB)

    Pakrashi, Sunandan; Dalai, Swayamprava; Chandrasekaran, Natarajan; Mukherjee, Amitava, E-mail: amit.mookerjea@gmail.com

    2014-07-01

    Highlights: • Trophic transfer of alumina nanoparticles using Chlorella ellipsoides and Ceriodaphnia dubia. • Subtle alterations in the feeding behaviour of the daphnids. • Disruption the energy flow through the food chain. • Transmission electron microscopy validated the disrupted feeding behaviour. - Abstract: The transfer of nanoparticles through the food chain can lead to bioaccumulation and biomagnification resulting in a long term negative impact on the ecosystem functions. The primary objective of this study was evaluation of aluminium oxide nanoparticles transfer from primary producers to primary consumers. A simple set up consisting of a primary producer (Chlorella ellipsoides) and a primary consumer (Ceriodaphnia dubia) was used. Here, C. ellipsoides were exposed to the varying concentrations of the nanoparticles ranging from 20 to 120 μg/mL (196 to 1176 μM) for 48 h and the infested algal cells were used as the feed to C. dubia. The bioaccumulation of the nanoparticles into the daphnids was noted and the biomagnification factors were computed. The exposure was noted to cause subtle alterations in the feeding behaviour of the daphnids. This might have long term consequences in the energy flow through the food chain. The reproductive behaviour of the daphnids remained unaffected upon exposure to nanoparticle infested algal feed. Distinct observations at ultra-structural scale using transmission electron microscopy provided visual evidences for the disrupted feeding behaviour upon exposure to nanoparticle treated algae. Internalization of nanoparticle like inclusion bodies in the intracellular space of algae was also detected. The findings were further substantiated by a detailed analysis of hydrodynamic stability, bioavailability and dissolution of ions from the nanoparticles over the exposure period. Altogether, the study brings out the first of its kind of observation of trophic transfer potential/behaviour of aluminium oxide nanoparticles and

  20. 50 CFR 660.412 - EFH identifications and descriptions for Pacific salmon.

    Science.gov (United States)

    2010-10-01

    ... Pacific salmon. 660.412 Section 660.412 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT... COAST STATES West Coast Salmon Fisheries § 660.412 EFH identifications and descriptions for Pacific salmon. Pacific salmon essential fish habitat (EFH) includes all those water bodies occupied or...

  1. Response of ecosystem metabolism to low densities of spawning Chinook salmon

    Science.gov (United States)

    Benjamin, Joseph R.; Bellmore, J. Ryan; Watson, Grace A.

    2016-01-01

    Marine derived nutrients delivered by large runs of returning salmon are thought to subsidize the in situ food resources that support juvenile salmon. In the Pacific Northwest, USA, salmon have declined to marine derived nutrients once provided by large salmon runs. We explored whether low densities (marine derived nutrients may inform nutrient augmentation studies aimed at enhancing fish populations.

  2. Diphyllobothrium nihonkaiense Tapeworm Larvae in Salmon from North America

    Science.gov (United States)

    Oros, Mikuláš; Ferguson, Jayde; Scholz, Tomáš

    2017-01-01

    Diphyllobothriosis is reemerging because of global importation and increased popularity of eating raw fish. We detected Diphyllobothrium nihonkaiense plerocercoids in the musculature of wild pink salmon (Oncorhynchus gorbuscha) from Alaska, USA. Therefore, salmon from the American and Asian Pacific coasts and elsewhere pose potential dangers for persons who eat these fish raw. PMID:28098540

  3. Future challanges for the maturing Norwegian salmon aquaculture industry

    DEFF Research Database (Denmark)

    Asche, Frank; Guttormsen, Atle G.; Nielsen, Rasmus

    2013-01-01

    In this paper, we analyze total factor productivity change in the Norwegian salmon aquaculture sector from 1996 to 2008. During this period, the production has on average been growing with 8% per year. At the same time, the price of salmon has stabilized indicating that an increase in demand is d...

  4. Histopathology of fish. II. The salmon-poisoning fluk

    Science.gov (United States)

    1956-01-01

    THE SALMON-POISONING FLUKE is misnamed as far as the fish culturist is concerned, for the disease affects dogs, not fish. There is considerable evidence, however, that fish may also suffer from the complex chain of events leading from snail to dying dog. Histological studies indicate that young salmon and trout may be severely damaged by the encysted stage of the fluke.

  5. SALMON AND THE ENDANGERED SPECIES ACT: TROUBLESOME QUESTIONS

    Science.gov (United States)

    Throughout the Pacific Northwest and California, all wild salmon runs have declined since 1850 and some have disappeared. A sustainable future for wild salmon remains elusive. In response to requirements of the U.S. Endangered Species Act, the Canadian Species at Risk Act, and ...

  6. Indirect benefits for female salmon from mating with brown trout.

    Science.gov (United States)

    Castillo, Ana G F; Beall, Edward; Morán, Paloma; Martinez, Jose L; Garcia-Vazquez, Eva

    2010-01-01

    By genetic analysis of 1625 samples from 10 south European rivers, we have found that Atlantic salmon Salmo salar hybridize with sympatric brown trout S. trutta in the wild and provide the female in most heterospecific crosses. Hybrids exhibit reduced fertility and could be considered a wasted reproductive effort by salmon females. In 7 experiments involving salmon females, large brown trout males, and small salmon male sneakers, reproductive success of Atlantic salmon females mating with brown trout males was not significantly different from that of 5 experiments of females mating with conspecific males because small Atlantic salmon sneakers fertilized most ova (mean 93%) in salmon x trout matings. Although egg retention tended to be higher in heterospecific than in conspecific crosses (mean 5.7% vs. 20.5% respectively), mean offspring survival was 24.4% and 30.3%, respectively (t = 1.5 x 10(-8), not significant). Brown trout males taking on a courting role may benefit late-maturing females in absence or scarcity of anadromous salmon males because they play a protective role against disturbances from other fishes (including cannibal sneakers).

  7. Disruption - Access cards service

    CERN Multimedia

    2014-01-01

    We would like to inform you that between 10 November and 15 December 2014, the access cards service in Building 55 will be disrupted, as the GS Department has decided to improve the facilities for users of this building. During the work, you will find the registration, biometric registration and dosimeter exchange services on the second floor of Building 55 and the vehicle sticker service on the ground floor along with the access cards service. We thank you for your understanding and apologise for any inconvenience caused.

  8. Manuel's asteroid disruption technique.

    Science.gov (United States)

    John, Manuel; Ipe, Abraham; Jacob, Ivan

    2015-06-01

    A seventy-year-old male presented with dense asteroid hyalosis in both eyes. He had undergone cataract extraction in one eye 3 years ago, and the other eye had immature cataract. Both the autorefractor and dilated streak retinoscopy did not give readings and subjective visual improvement could not be achieved. Immediately following YAG posterior capsulotomy and anterior vitreous asteroid disruption, the vision improved to 20/20 with recordable auto refractor and streak retinoscopy values. Our initial experience indicates that the treatment is simple, safe and effective but needs controlled and prospective studies to confirm its long-term safety.

  9. Disrupted Refugee Family Life

    DEFF Research Database (Denmark)

    Shapiro, Ditte Krogh

    2017-01-01

    of family members in social historical contexts. Studying the multiple perspectives of family members shows how social support conceptualized as care practises is conflictual in the changing everyday family practices that are transformed by policy. The purpose of studying how families manage to flee civil......Fleeing civil war involves managing life threatening events and multiple disruptions of everyday life. The theoretical potentials of analysing the recreation of everyday family life among Syrian refugees in Denmark is explored based on conceptualizations that emphasize the collective agency...

  10. Future of Pacific salmon in the face of environmental change: Lessons from one of the world's remaining productive salmon regions

    Science.gov (United States)

    Schoen, Erik R.; Wipfli, Mark S.; Trammell, Jamie; Rinella, Daniel J.; Floyd, Angelica L.; Grunblatt, Jess; McCarthy, Molly D.; Meyer, Benjamin E.; Morton, John M.; Powell, James E.; Prakash, Anupma; Reimer, Matthew N.; Stuefer, Svetlana L.; Toniolo, Horacio; Wells, Brett M.; Witmer, Frank D. W.

    2017-01-01

    Pacific salmon Oncorhynchus spp. face serious challenges from climate and landscape change, particularly in the southern portion of their native range. Conversely, climate warming appears to be allowing salmon to expand northwards into the Arctic. Between these geographic extremes, in the Gulf of Alaska region, salmon are at historically high abundances but face an uncertain future due to rapid environmental change. We examined changes in climate, hydrology, land cover, salmon populations, and fisheries over the past 30–70 years in this region. We focused on the Kenai River, which supports world-famous fisheries but where Chinook Salmon O. tshawytscha populations have declined, raising concerns about their future resilience. The region is warming and experiencing drier summers and wetter autumns. The landscape is also changing, with melting glaciers, wetland loss, wildfires, and human development. This environmental transformation will likely harm some salmon populations while benefiting others. Lowland salmon streams are especially vulnerable, but retreating glaciers may allow production gains in other streams. Some fishing communities harvest a diverse portfolio of fluctuating resources, whereas others have specialized over time, potentially limiting their resilience. Maintaining diverse habitats and salmon runs may allow ecosystems and fisheries to continue to thrive amidst these changes.

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

    Science.gov (United States)

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

  12. Antibody against infectious salmon anaemia virus among feral Atlantic salmon (Salmo salar)

    Science.gov (United States)

    Cipriano, R.C.

    2009-01-01

    Archived sera from Atlantic salmon (Salmo salar) that returned to the Penobscot River (Maine), Merrimack River (Massachusetts), and Connecticut River (in Massachusetts) from 1995 to 2002 were analysed for antibodies against infectious salmon anaemia virus (ISAV) using an enzyme-linked immunosorbent assay (ELISA). Up to 60 samples were archived per river system per year. In a given year, the number of fish sampled by ELISA for ISAV antibodies in the Penobscot River ranged from 2.9 to 11.2, and the range of salmon sampled in the Merrimack River and the Connecticut River was 31.3-100 and 20.0-67.5, respectively. Archived sera were not available for the 1995 and 2002 year classes from the Connecticut River. In all, 1141 samples were processed; 14 serum samples tested positive for antibodies to ISAV. In the Penobscot River, serum from one fish tested positive in each of the 1995 and 1999 year-class returns, and sera from two fish tested positive in the 1998 returns. In the Merrimack River, sera from four fish tested positive in each of the 1996 and 1997 returns, and sera from two fish were positive in the 2002 return. None of the archived sera from Atlantic salmon that returned to the Connecticut River tested positive. ?? 2009 United States Government, Department of the Interior.

  13. Salmon Farming and Salmon People: Identity and Environment in the Leggatt Inquiry

    Science.gov (United States)

    Schreiber, Dorothee

    2003-01-01

    In October of 2001, the Leggatt Inquiry into salmon farming traveled to four small communities (Port Hardy, Tofino, Alert Bay, and Campbell River) close to the centers of operation for the finfish aquaculture industry in British Columbia. In doing so, it gave local people, particularly First Nations people, an opportunity to speak about salmon…

  14. Effect of Inclusion of Salmon Roe on Characteristics of Salmon Baby Food Products

    Science.gov (United States)

    Baby food was formulated from sockeye salmon (puree alone, puree +chunks, puree +pink row, puree +pink row +chunks, puree +red row, puree +red roe +chunks). In the 1st study, physical (pH, instrumental color, water activity) and descriptive sensory (odor, flavor, texture, visual color) characteristi...

  15. Relativistic tidal disruption events

    Directory of Open Access Journals (Sweden)

    Levan A.

    2012-12-01

    Full Text Available In March 2011 Swift detected an extremely luminous and long-lived outburst from the nucleus of an otherwise quiescent, low luminosity (LMC-like galaxy. Named Swift J1644+57, its combination of high-energy luminosity (1048 ergs s−1 at peak, rapid X-ray variability (factors of >100 on timescales of 100 seconds and luminous, rising radio emission suggested that we were witnessing the birth of a moderately relativistic jet (Γ ∼ 2 − 5, created when a star is tidally disrupted by the supermassive black hole in the centre of the galaxy. A second event, Swift J2058+0516, detected two months later, with broadly similar properties lends further weight to this interpretation. Taken together this suggests that a fraction of tidal disruption events do indeed create relativistic outflows, demonstrates their detectability, and also implies that low mass galaxies can host massive black holes. Here, I briefly outline the observational properties of these relativistic tidal flares observed last year, and their evolution over the first year since their discovery.

  16. Integrating microbes into food-chains: Insect trophic identity reflects rampant microbivory

    Science.gov (United States)

    Detritivory is the dominant trophic paradigm in most terrestrial, aquatic, and marine ecosystems, yet accurate measurement of consumer trophic position within detrital (= ‘brown’) food-webs has remained relatively impenetrable. Measurement of detritivore trophic position is complicated by the fact t...

  17. Horizontal and vertical distribution of sea lice larvae (Lepeophtheirus salmonis) in and around salmon farms in the Bay of Fundy, Canada.

    Science.gov (United States)

    Nelson, E J; Robinson, S M C; Feindel, N; Sterling, A; Byrne, A; Pee Ang, K

    2017-11-21

    The sea louse, Lepeophtheirus salmonis, is parasitic to salmonid species in the Northern Hemisphere and has become a widespread biological and economic problem for the salmon farming industry. A better understanding is needed of their spatial distribution and early life history to disrupt the life cycle of the sea louse. In this study, sea lice larval densities within salmon farms, between salmon farms and reference sites, and at various depths were quantified using both plankton pumps and plankton nets. Farm sites exhibited significantly higher densities than reference sites; however, these densities dropped an order of magnitude at a distance of 100 m from the cages. The majority of the larvae captured in the study were nauplii (93%), and densities ranged from 0 to 10 larvae/m3 . Free-swimming sea lice larvae were found to exhibit a diel cycle where nauplii larvae were in deeper waters (10-17 m) during the day and in surface waters (1-6 m) during the night. The results of this study suggest that the early life-history stages of sea lice originate from and may remain close to active salmon farms, creating a self-sustaining population. © 2017 Her Majesty the Queen in Right of Canada. Journal of Fish Diseases © 2017 John Wiley & Sons Ltd Reproduced with the permission of the Minister of Fisheries and Oceans of Canada.

  18. Aluminum exposure impacts brain plasticity and behavior in Atlantic salmon (Salmo salar).

    Science.gov (United States)

    Grassie, C; Braithwaite, V A; Nilsson, J; Nilsen, T O; Teien, H-C; Handeland, S O; Stefansson, S O; Tronci, V; Gorissen, M; Flik, G; Ebbesson, L O E

    2013-08-15

    Aluminum (Al) toxicity occurs frequently in natural aquatic ecosystems as a result of acid deposition and natural weathering processes. Detrimental effects of Al toxicity on aquatic organisms are well known and can have consequences for survival. Fish exposed to Al in low pH waters will experience physiological and neuroendocrine changes that disrupt homeostasis and alter behavior. To investigate the effects of Al exposure on both the brain and behavior, Atlantic salmon (Salmo salar) kept in water treated with Al (pH 5.7, 0.37±0.04 μmol 1(-1) Al) for 2 weeks were compared with fish kept in under control conditions (pH 6.7, physiological stress, indicated by elevated plasma cortisol and glucose levels. Here we show for the first time that exposure to Al in acidic conditions also impaired learning performance in a maze task. Al toxicity also reduced the expression of NeuroD1 transcript levels in the forebrain of exposed fish. As in mammals, these data show that exposure to chronic stress, such as acidified Al, can reduce neural plasticity during behavioral challenges in salmon, and may impair the ability to cope with new environments.

  19. Trophic Ecology of Some Common Juvenile Fish Species in Mtwapa ...

    African Journals Online (AJOL)

    The trophic status of common fish species in Mtwapa creek on the Kenyan coast was studied. Both the qualitative and quantitative spectra of the diets of these fish species were investigated. It was found that the eight most abundant fish species, Sardinella gibbosa, Pellona ditchella, Spratelloides delicatilus, Atherinomorous ...

  20. Squid as trophic bridges for parasite flow within marine ecosystems ...

    African Journals Online (AJOL)

    Squid as trophic bridges for parasite flow within marine ecosystems: The case of anisakis simplex (nematoda: Anisakidae), or when the wrong way can be right. E Abollo, C Gestal, A López, AF González, A Guerra, S Pascual ...

  1. Mesoscale eddies are oases for higher trophic marine life

    KAUST Repository

    Godø, Olav R.

    2012-01-17

    Mesoscale eddies stimulate biological production in the ocean, but knowledge of energy transfers to higher trophic levels within eddies remains fragmented and not quantified. Increasing the knowledge base is constrained by the inability of traditional sampling methods to adequately sample biological processes at the spatio-temporal scales at which they occur. By combining satellite and acoustic observations over spatial scales of 10 s of km horizontally and 100 s of m vertically, supported by hydrographical and biological sampling we show that anticyclonic eddies shape distribution and density of marine life from the surface to bathyal depths. Fish feed along density structures of eddies, demonstrating that eddies catalyze energy transfer across trophic levels. Eddies create attractive pelagic habitats, analogous to oases in the desert, for higher trophic level aquatic organisms through enhanced 3-D motion that accumulates and redistributes biomass, contributing to overall bioproduction in the ocean. Integrating multidisciplinary observation methodologies promoted a new understanding of biophysical interaction in mesoscale eddies. Our findings emphasize the impact of eddies on the patchiness of biomass in the sea and demonstrate that they provide rich feeding habitat for higher trophic marine life. 2012 God et al.

  2. Trophic position of coexisting krill species: a stable isotope approach

    DEFF Research Database (Denmark)

    Agersted, Mette Dalgaard; Bode, Antonio; Nielsen, Torkel Gissel

    2014-01-01

    Four krill species with overlapping functional biology coexist in Greenland waters. Here, we used stable isotopes to investigate and discuss their trophic role and mode of coexistence. Bulk carbon (δ13C) and nitrogen (δ15N) stable isotope analyses of Thysanoessa longicaudata, T. inermis, T. raschii...

  3. Assessing Trophic Position and Mercury Accumulation in Sanpping Turtles

    Science.gov (United States)

    This study determined the trophic position and the total mercury concentrations of snapping turtles (Chelydra serpentina) captured from 26 freshwater sites in Rhode Island. Turtles were captured in baited wire cages, and a non-lethal sampling technique was used in which tips of ...

  4. Trophic state categorisation and assessment of water quality in ...

    African Journals Online (AJOL)

    In this study we investigated the water quality, determined the trophic state and assessed the influence of lake zones on the physical-chemical parameters of the Manjirenji Dam, Zimbabwe. Furthermore, we tested the applicability of two customary temperate water quality indices, the Canadian Council of Ministers of the ...

  5. Changes in the trophic structure of the northern Benguela before ...

    African Journals Online (AJOL)

    The dominant small pelagic fish, characteristic of upwelling systems, were replaced by a wider range of species, and biomass of gelatinous zooplankton appears to have increased dramatically in recent decades. Catches declined, and mean trophic level of the catch increased from 3.18 in 1967 to 3.68 in 1990, as did the ...

  6. Assessing trophic adaptability is critical for understanding the ...

    African Journals Online (AJOL)

    Predators dependent on a narrow range of prey species should respond rapidly to shifts in the distribution of their prey, whereas those with broad trophic adaptability may respond to shifts in their prey by altering their diet. Small pelagic fishes are an extremely important component of the diet of many marine predators.

  7. Changes in the trophic structure, abundance and species diversity of ...

    African Journals Online (AJOL)

    ... the biomass of high trophic level species and indices of species diversity between 1990 and 2009 were observed in commercial catches. These decreases were then related to changes in fishing pressure, fishing strategy and the combined effects of fishing and environmental factors (as derived from satellite observations) ...

  8. Trophic structure and biomass distribution on two East Cape rocky ...

    African Journals Online (AJOL)

    1980-01-12

    Jan 12, 1980 ... Trophic structure and biomass distribution on two. East Cape rocky shores. A Mclachlan, H.W. Lombard and S. Louwrens. Zoology Department, University of Port Elizabeth, Port Elizabeth. The distribution and biomass of macrofauna and macroalgae is described for two intertidal rocky shores near Port Eliza ...

  9. Trait-mediated trophic interactions: is foraging theory keeping up?

    Science.gov (United States)

    Steven F. Railsback; Bret C. Harvey

    2013-01-01

    Many ecologists believe that there is a lack of foraging theory that works in community contexts, for populations of unique individuals each making trade-offs between food and risk that are subject to feedbacks from behavior of others. Such theory is necessary to reproduce the trait-mediated trophic interactions now recognized as widespread and strong. Game theory can...

  10. Mesoscale eddies are oases for higher trophic marine life.

    Directory of Open Access Journals (Sweden)

    Olav R Godø

    Full Text Available Mesoscale eddies stimulate biological production in the ocean, but knowledge of energy transfers to higher trophic levels within eddies remains fragmented and not quantified. Increasing the knowledge base is constrained by the inability of traditional sampling methods to adequately sample biological processes at the spatio-temporal scales at which they occur. By combining satellite and acoustic observations over spatial scales of 10 s of km horizontally and 100 s of m vertically, supported by hydrographical and biological sampling we show that anticyclonic eddies shape distribution and density of marine life from the surface to bathyal depths. Fish feed along density structures of eddies, demonstrating that eddies catalyze energy transfer across trophic levels. Eddies create attractive pelagic habitats, analogous to oases in the desert, for higher trophic level aquatic organisms through enhanced 3-D motion that accumulates and redistributes biomass, contributing to overall bioproduction in the ocean. Integrating multidisciplinary observation methodologies promoted a new understanding of biophysical interaction in mesoscale eddies. Our findings emphasize the impact of eddies on the patchiness of biomass in the sea and demonstrate that they provide rich feeding habitat for higher trophic marine life.

  11. Size, Length-Weight Relationships, Reproduction And Trophic ...

    African Journals Online (AJOL)

    Size, Length-Weight Relationships, Reproduction And Trophic Biology Of Chrysichthys nigrodigitatus And Chrysichthys auratus (Siluriformes: Bagridae) In A ... The high Spearman's rank coefficient (r = 0.75) and the Raabe's factor (R = 59.0%, %FO; 56.8%, VI) show strong similarity and overlap in the food types of the two ...

  12. Aspects of the trophic ecology of Liza falcipinnis (Valenciennes 1836)

    African Journals Online (AJOL)

    Aspects of the trophic ecology of Liza falcipinnis (Valenciennes 1836) (Pisces: Mugilidae) in the Cross River Estuary (Nigeria) ... From the index of relative importance (IRI), L. falcipinnis fed primarily on diatoms, FPOM, mud, sand, secondarily on CPOM, prey fish, green algae and blue-green algae while free living ...

  13. Trophic relationships of hake ( Merluccius capensis and M ...

    African Journals Online (AJOL)

    The trophic relationships of two hake species (Merluccius capensis and M. paradoxus) and three shark species (Centrophorus squamosus, Deania calcea and D. profundorum) were investigated using nitrogen and carbon stable isotope signatures (δ15N and δ13C) of their muscle tissues. The sharks were more enriched in ...

  14. Trophic interactions amongst the plankton in the temporarily open ...

    African Journals Online (AJOL)

    The trophic interactions between bacteria, phytoplankton, nanoflagellates (2–20 µm), microzooplankton (20–200 µm) and mesozooplankton (200–2 000 µm) were investigated in winter and summer in the temporarily open/closed East Kleinemonde Estuary, Eastern Cape. During winter the phytoplankton community was ...

  15. Disruptive behavior within the workplace.

    Science.gov (United States)

    Small, Charlene R; Porterfield, Susan; Gordon, Glenna

    2015-05-01

    The aim of this study was to determine the incidence of disruptive behavior among nurses in the healthcare workplace, the details that are associated with its occurrence, and the organizational procedures utilized when disruptive incidents occur. Healthcare workers have a higher risk of experiencing disruptive behavior among staff in the workplace compared to other industries, and nurses are more susceptible than other healthcare workers. A quantitative, descriptive, survey design asked nurses if they had experienced disruptive behavior within the past 12 months and how this was handled by their organization. Disruptive behavior included any type of verbal abuse, electronic or e-mail abuse, or physical abuse within the work environment. There were 2,821 participants that validated the occurrence of verbal, electronic, and physical disruptive behavior, and the majority rated their overall work environment to be at high risk of experiencing disruptive behavior at least once every 6 months. Twenty-four statistically significant relationships were found with strongest associations (disruptive behavior and position; and feeling comfortable reporting the abuse and position as well as education. It is evident that disruptive behavior exists verbally, electronically, and physically, and that the overall work environment is felt to be at high risk of experiencing repeated disruptive behavior. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Evaluation of Fall Chinook and Chum Salmon Spawning below Bonneville Dam; 2004-2005 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    van der Naald, Wayne; Duff, Cameron; Friesen, Thomas A. (Oregon Department of Fish and Wildlife, Clackamas, OR)

    2006-02-01

    Pacific salmon Oncorhynchus spp. populations have declined over the last century due to a variety of human impacts. Chum salmon O. keta populations in the Columbia River have remained severely depressed for the past several decades, while upriver bright (URB) fall Chinook salmon O. tschawytscha populations have maintained relatively healthy levels. For the past seven years we have collected data on adult spawning and juvenile emergence and outmigration of URB fall Chinook and chum salmon populations in the Ives and Pierce islands complex below Bonneville Dam. In 2004, we estimated 1,733 fall Chinook salmon and 336 chum salmon spawned in our study area. Fall Chinook salmon spawning peaked 19 November with 337 redds and chum salmon spawning peaked 3 December with 148 redds. Biological characteristics continue to suggest chum salmon in our study area are similar to nearby stocks in Hardy and Hamilton creeks, and Chinook salmon we observe are similar to upriver bright stocks. Temperature data indicated that 2004 brood URB fall Chinook salmon emergence began on 6 January and ended 27 May 2005, with peak emergence occurring 12 March. Chum salmon emergence began 4 February and continued through 2 May 2005, with peak emergence occurring on 21 March. Between 13 January and 28 June, we sampled 28,984 juvenile Chinook salmon and 1,909 juvenile chum salmon. We also released 32,642 fin-marked and coded-wire tagged juvenile fall Chinook salmon to assess survival. The peak catch of juvenile fall Chinook salmon occurred on 18 April. Our results suggested that the majority of fall Chinook salmon outmigrate during late May and early June, at 70-80 mm fork length (FL). The peak catch of juvenile chum salmon occurred 25 March. Juvenile chum salmon appeared to outmigrate at 40-55 mm FL. Outmigration of chum salmon peaked in March but extended into April and May.

  17. Mitochondrial DNA variation in chinook salmon and chum salmon detected by restriction enzyme analysis of polymerase chain reaction products

    Science.gov (United States)

    Cronin, M.; Spearman, R.; Wilmot, R.; Patton, J.; Bickman, J.

    1993-01-01

    We analyze intraspecific mitochondrial DNA variation in chinook salmon from drainages in the Yukon River, the Kenai River, and Oregon and California rivers; and chum salmon from the Yukon River and vancouver Island, and Washington rivers. For each species, three different portions of the mtDNA molecule were amplified seperately using the polymerase chain reaction and then digested with at least 19 restrictions enzymes. Intraspecific sequence divergences between haplotypes were less than 0.01 base subsitution per nucleotide. Nine chum salmon haplotypes were identified. Yukon River chum salmon stocks displayed more haplotypes (8) occurred in all areas. Seven chinook salmon haplotypes were identified. Four haplotypes occurred in the Yukon and Kenai rviers and four occured in the Oregon/California, with only one haplotype shared between the regions. Sample sizes were too small to quantify the degree of stock seperation among drainages, but the patterns of variation that we observed suggest utility of the technique in genetic stock identification.

  18. Diel horizontal migration in streams: juvenile fish exploit spatial heterogeneity in thermal and trophic resources

    Science.gov (United States)

    Armstrong, Jonathan B.; Schindler, Daniel E.; Ruff, Casey P.; Brooks, Gabriel T.; Bentley, Kale E.; Torgersen, Christian E.

    2013-01-01

    Vertical heterogeneity in the physical characteristics of lakes and oceans is ecologically salient and exploited by a wide range of taxa through diel vertical migration to enhance their growth and survival. Whether analogous behaviors exploit horizontal habitat heterogeneity in streams is largely unknown. We investigated fish movement behavior at daily timescales to explore how individuals integrated across spatial variation in food abundance and water temperature. Juvenile coho salmon made feeding forays into cold habitats with abundant food, and then moved long distances (350–1300 m) to warmer habitats that accelerated their metabolism and increased their assimilative capacity. This behavioral thermoregulation enabled fish to mitigate trade-offs between trophic and thermal resources by exploiting thermal heterogeneity. Fish that exploited thermal heterogeneity grew at substantially faster rates than did individuals that assumed other behaviors. Our results provide empirical support for the importance of thermal diversity in lotic systems, and emphasize the importance of considering interactions between animal behavior and habitat heterogeneity when managing and restoring ecosystems.

  19. Development of the salmon louse Lepeophtheirus salmonis and its effects on juvenile sockeye salmon Oncorhynchus nerka.

    Science.gov (United States)

    Jakob, E; Sweeten, T; Bennett, W; Jones, S R M

    2013-11-06

    Responses of sockeye salmon Oncorhynchus nerka during infection with Lepeophtheirus salmonis were assessed in controlled laboratory trials. Juvenile salmon were exposed to 100 copepodids fish-1 (Trials 1 and 2) or 300 copepodids fish-1 (Trial 3) at mean weights of approximately 40, 80 and 135 g, respectively. Infections occurred on all salmon in all trials, and mean abundances (infection densities) ranged between 3.3 and 19.4 lice fish-1 (0.08 and 0.44 lice g-1 fish) in Trial 1, between 7.2 and 18.3 (0.09 and 0.22) in Trial 2 and between 19.5 and 60.7 (0.15 and 0.46) in Trial 3. A cumulative mortality of 24.4% occurred in Trial 3. At attachment sites on gills, we observed hyperplasia of basal epithelial cells and fusion of secondary lamellae occasionally associated with a cellular infiltrate. At attachment sites on fins, partial to complete skin erosion occurred, with limited evidence of hyperplasia or inflammation. Scale loss and abrasions coincided with pre-adult lice around 20 d post infection (dpi). Plasma osmolality was significantly elevated in exposed fish in Trials 1 (21 dpi), 2 (15 and 36 dpi) and 3 (20 dpi), whereas haematocrit was significantly depressed in exposed fish in Trials 1 (21 and 28 dpi) and 3 (20 dpi). Plasma cortisol was significantly elevated in exposed fish at 20 dpi (Trial 3). Physiological changes and mortality were related to the intensity of infection and became most prominent with pre-adult stages, suggesting patterns of infection and response in sockeye salmon similar to those reported for Atlantic and Chinook salmon.

  20. 50 CFR Table 1 to Subpart H of... - Pacific Salmon EFH Identified by USGS Hydrologic Unit Code (HUC)

    Science.gov (United States)

    2010-10-01

    ... Name Salmon Species Impassible Man-made Barrier (if present) 17110001 WA Fraser (Whatcom) Coho salmon n... Lower Columbia-Sandy River Chinook and coho salmon Impassable Man-made Barrier 17080002 WA Lewis River... salmon n/a 17020016 WA Upper Columbia - Priest Rapids Chinook and coho salmon n/a 17060101 OR/ID Hells...

  1. Trophic ecomorphology of Siluriformes (Pisces, Osteichthyes) from a tropical stream.

    Science.gov (United States)

    Pagotto, J P A; Goulart, E; Oliveira, E F; Yamamura, C B

    2011-05-01

    The present study analysed the relationship between morphology and trophic structure of Siluriformes (Pisces, Osteichthyes) from the Caracu Stream (22º 45' S and 53º 15' W), a tributary of the Paraná River (Brazil). Sampling was carried out at three sites using electrofishing, and two species of Loricariidae and four of Heptapteridae were obtained. A cluster analysis revealed the presence of three trophic guilds (detritivores, insectivores and omnivores). Principal components analysis demonstrated the segregation of two ecomorphotypes: at one extreme there were the detritivores (Loricariidae) with morphological structures that are fundamental in allowing them to fix themselves to substrates characterised by rushing torrents, thus permitting them to graze on the detritus and organic materials encrusted on the substrate; at the other extreme of the gradient there were the insectivores and omnivores (Heptapteridae), with morphological characteristics that promote superior performance in the exploitation of structurally complex habitats with low current velocity, colonised by insects and plants. Canonical discriminant analysis revealed an ecomorphological divergence between insectivores, which have morphological structures that permit them to capture prey in small spaces among rocks, and omnivores, which have a more compressed body and tend to explore food items deposited in marginal backwater zones. Mantel tests showed that trophic structure was significantly related to the body shape of a species, independently of the phylogenetic history, indicating that, in this case, there was an ecomorphotype for each trophic guild. Therefore, the present study demonstrated that the Siluriformes of the Caracu Stream were ecomorphologically structured and that morphology can be applied as an additional tool in predicting the trophic structure of this group.

  2. Trophic ecomorphology of Siluriformes (Pisces, Osteichthyes from a tropical stream

    Directory of Open Access Journals (Sweden)

    JPA Pagotto

    Full Text Available The present study analysed the relationship between morphology and trophic structure of Siluriformes (Pisces, Osteichthyes from the Caracu Stream (22º 45' S and 53º 15' W, a tributary of the Paraná River (Brazil. Sampling was carried out at three sites using electrofishing, and two species of Loricariidae and four of Heptapteridae were obtained. A cluster analysis revealed the presence of three trophic guilds (detritivores, insectivores and omnivores. Principal components analysis demonstrated the segregation of two ecomorphotypes: at one extreme there were the detritivores (Loricariidae with morphological structures that are fundamental in allowing them to fix themselves to substrates characterised by rushing torrents, thus permitting them to graze on the detritus and organic materials encrusted on the substrate; at the other extreme of the gradient there were the insectivores and omnivores (Heptapteridae, with morphological characteristics that promote superior performance in the exploitation of structurally complex habitats with low current velocity, colonised by insects and plants. Canonical discriminant analysis revealed an ecomorphological divergence between insectivores, which have morphological structures that permit them to capture prey in small spaces among rocks, and omnivores, which have a more compressed body and tend to explore food items deposited in marginal backwater zones. Mantel tests showed that trophic structure was significantly related to the body shape of a species, independently of the phylogenetic history, indicating that, in this case, there was an ecomorphotype for each trophic guild. Therefore, the present study demonstrated that the Siluriformes of the Caracu Stream were ecomorphologically structured and that morphology can be applied as an additional tool in predicting the trophic structure of this group.

  3. De novo lipogenesis in Atlantic salmon adipocytes.

    Science.gov (United States)

    Bou, Marta; Todorčević, Marijana; Torgersen, Jacob; Škugor, Stanko; Navarro, Isabel; Ruyter, Bente

    2016-01-01

    Carnivorous teleost fish utilize glucose poorly, and the reason for this is not known. It is possible that the capacity of adipocytes to synthesize lipids from carbohydrate precursors through a process known as "de novo lipogenesis" (DNL) is one of the factors that contributes to glucose intolerance in Atlantic salmon. Primary adipocytes from Atlantic salmon differentiated in vitro were incubated with radiolabelled glucose in order to explore the capacity of salmon adipocytes to synthesize and deposit lipids from glucose through DNL. The lipid-storage capacity of adipocytes incubated with glucose was compared with that of cells incubated with the fatty acid palmitic acid. Quantitative PCR and immunohistochemistry were used to assess changes of genes and proteins involved in glucose and lipid transport and metabolism. Less than 0.1% of the radiolabelled glucose was metabolized to the fatty acids 16:0 and the stearoyl-CoA desaturase products 16:1 and 18:1 by DNL, whereas approximately 40% was converted to glycerol to form the triacylglycerol backbone of lipids. Transcriptional analysis indicated that adipocytes ensure the availability of necessary cofactors and other substrates for lipid synthesis and storage from glycolysis, the pentose phosphate pathway and glyceroneogenesis. We have shown for the first time that the DNL pathway is active in fish adipocytes. The capacity of the pathway to convert glucose into cellular lipids for storage is relatively low. The limited capacity of adipocytes to utilize glucose as a substrate for lipid deposition may contribute to glucose intolerance in salmonids. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Disruptive Co-Creation?

    DEFF Research Database (Denmark)

    Butler, Ivan; Christensen, David

    set up to foster innovative partnerships between civil society organizations, businesses and academia with the objective of supporting disruptive business model innovation in co-creation processes across these sectors. This paper delves into state-of-the-art concerning literature pertinent......Faced with constant changes in the marketplace and increasing pressure to adapt to e.g. recessive and saturated conditions, businesses in industrialized countries have the option to pursue opportunities in emerging markets. In the poorest of developing countries, there is a proposition of high......-payoff, albeit high-risk opportunities for sustainable business models that address poverty alleviation. However, many businesses exhibit hesitation and wariness before giving serious consideration toward entering markets in e.g. Sub-Saharan Africa. In addressing this, the initiative access2innovation has been...

  5. Trophic levels of fish species of commercial importance in the Colombian Caribbean.

    Science.gov (United States)

    García, Camilo B; Contreras, Cristian Camilo

    2011-09-01

    Ecological studies on commercial important fish species are of great value to support resource management issues. This study calculated trophic levels of those Colombian Caribbean fish species whose diet has been locally described. Usable diet data of 119 species resulted in 164 trophic level estimates. An ordinary regression model relating trophic level and fish size was formulated. The regression slope was positive and significantly different from zero (p fish size. Both the list of trophic levels and the regression model should be of help in the formulation of trophic indicators and models of neotropical ecosystems.

  6. Disrupting the Industry with Play

    DEFF Research Database (Denmark)

    Lund, Henrik Hautop

    2016-01-01

    Decades of research into intelligent, playful technology and user-friendly man-machine interfaces has provided important insight into the creation of robotic systems and intelligent interactive systems which are much more user-friendly, safer and cheaper than what appeared possible merely a decade...... or two ago. This is significantly disrupting the industry in several market sectors. This paper describes the components of the playware and embodied artificial intelligence research that has led to disruption in the industrial robotics sector, and which points to the next disruption of the health care......, anytime to use these systems, providing an unforeseen flexibility into the sectors, which become disrupted with these systems....

  7. Chemical data for 7 streams in Salmon River Basin - Importance of biotic and abiotic features of salmon habitat implications for juvenile Chinook and steelhead growth and survival

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is a large-scale, long-term comparative study that includes many streams (20+ streams in the Salmon River Basin, Idaho, including a few non-salmon streams for...

  8. Radio telemetry data - Characterizing migration and survival for juvenile Snake River sockeye salmon between the upper Salmon River basin and Lower Granite Dam

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This project estimates survival and characterizes the migration of juvenile sockeye salmon between the upper Salmon River basin in central Idaho and Lower Granite...

  9. Determinants of Public Attitudes to Genetically Modified Salmon

    Science.gov (United States)

    Amin, Latifah; Azad, Md. Abul Kalam; Gausmian, Mohd Hanafy; Zulkifli, Faizah

    2014-01-01

    The objective of this paper is to assess the attitude of Malaysian stakeholders to genetically modified (GM) salmon and to identify the factors that influence their acceptance of GM salmon using a structural equation model. A survey was carried out on 434 representatives from various stakeholder groups in the Klang Valley region of Malaysia. Public attitude towards GM salmon was measured using self-developed questionnaires with seven-point Likert scales. The findings of this study have confirmed that public attitudes towards GM salmon is a complex issue and should be seen as a multi-faceted process. The most important direct predictors for the encouragement of GM salmon are the specific application-linked perceptions about religious acceptability of GM salmon followed by perceived risks and benefits, familiarity, and general promise of modern biotechnology. Encouragement of GM salmon also involves the interplay among other factors such as general concerns of biotechnology, threatening the natural order of things, the need for labeling, the need for patenting, confidence in regulation, and societal values. The research findings can serve as a database that will be useful for understanding the social construct of public attitude towards GM foods in a developing country. PMID:24489695

  10. Determinants of public attitudes to genetically modified salmon.

    Directory of Open Access Journals (Sweden)

    Latifah Amin

    Full Text Available The objective of this paper is to assess the attitude of Malaysian stakeholders to genetically modified (GM salmon and to identify the factors that influence their acceptance of GM salmon using a structural equation model. A survey was carried out on 434 representatives from various stakeholder groups in the Klang Valley region of Malaysia. Public attitude towards GM salmon was measured using self-developed questionnaires with seven-point Likert scales. The findings of this study have confirmed that public attitudes towards GM salmon is a complex issue and should be seen as a multi-faceted process. The most important direct predictors for the encouragement of GM salmon are the specific application-linked perceptions about religious acceptability of GM salmon followed by perceived risks and benefits, familiarity, and general promise of modern biotechnology. Encouragement of GM salmon also involves the interplay among other factors such as general concerns of biotechnology, threatening the natural order of things, the need for labeling, the need for patenting, confidence in regulation, and societal values. The research findings can serve as a database that will be useful for understanding the social construct of public attitude towards GM foods in a developing country.

  11. The characteristics of railway service disruption: implications for disruption management.

    Science.gov (United States)

    Golightly, D; Dadashi, N

    2017-03-01

    Rail disruption management is central to operational continuity and customer satisfaction. Disruption is not a unitary phenomenon - it varies by time, cause, location and complexity of coordination. Effective, user-centred technology for rail disruption must reflect this variety. A repertory grid study was conducted to elicit disruption characteristics. Construct elicitation with a group of experts (n = 7) captured 26 characteristics relevant to rail disruption. A larger group of operational staff (n = 28) rated 10 types of rail incident against the 26 characteristics. The results revealed distinctions such as business impact and public perception, and the importance of management of the disruption over initial detection. There were clear differences between those events that stop the traffic, as opposed to those that only slow the traffic. The results also demonstrate the utility of repertory grid for capturing the characteristics of complex work domains. Practitioner Summary: The aim of the paper is to understand how variety in rail disruption influences socio-technical design. It uses repertory grid to identify and prioritise 26 constructs, and group 10 disruption types, identifying critical factors such as whether an incident stops or merely slows the service, and business reputation.

  12. Trophic flexibility and the persistence of understory birds in intensively logged rainforest.

    Science.gov (United States)

    Edwards, David P; Woodcock, Paul; Newton, Rob J; Edwards, Felicity A; Andrews, David J R; Docherty, Teegan D S; Mitchell, Simon L; Ota, Takahiro; Benedick, Suzan; Bottrell, Simon H; Hamer, Keith C

    2013-10-01

    Effects of logging on species composition in tropical rainforests are well known but may fail to reveal key changes in species interactions. We used nitrogen stable-isotope analysis of 73 species of understory birds to quantify trophic responses to repeated intensive logging of rainforest in northern Borneo and to test 4 hypotheses: logging has significant effects on trophic positions and trophic-niche widths of species, and the persistence of species in degraded forest is related to their trophic positions and trophic-niche widths in primary forest. Species fed from higher up the food chain and had narrower trophic-niche widths in degraded forest. Species with narrow trophic-niche widths in primary forest were less likely to persist after logging, a result that indicates a higher vulnerability of dietary specialists to local extinction following habitat disturbance. Persistence of species in degraded forest was not related to a species' trophic position. These results indicate changes in trophic organization that were not apparent from changes in species composition and highlight the importance of focusing on trophic flexibility over the prevailing emphasis on membership of static feeding guilds. Our results thus support the notion that alterations to trophic organization and interactions within tropical forests may be a pervasive and functionally important hidden effect of forest degradation. © 2013 Society for Conservation Biology.

  13. A virus disease of sockeye salmon: Interim report

    Science.gov (United States)

    Watson, S.W.; Guenther, R.W.; Rucker, R.R.

    1954-01-01

    Since 1951 a disease, usually occurring in late spring or early summer, has caused severe losses in 3- to 12-month-old fingerling sockeye salmon in hatcheries in the State of Washington. The disease is characterized by an explosive outbreak, mortality usually 80 percent or greater, and a residual spinal deformity in a small percentage of the surviving fish, and its specificity for the one species of salmon, Oncorhynchus nerka. (The anadromous strain of this species is commonly known as sockeye, blueback, or red salmon, while the fresh-water strain is called kokanee or silver trout.) The etiological agent is believed to be a virus.

  14. Production of trout offspring from triploid salmon parents.

    Science.gov (United States)

    Okutsu, Tomoyuki; Shikina, Shinya; Kanno, Megumi; Takeuchi, Yutaka; Yoshizaki, Goro

    2007-09-14

    Many salmonids have become at risk of extinction. For teleosts whose eggs cannot be cryopreserved, developing techniques other than egg cryopreservation to save genetic resources is imperative. In this study, spermatogonia from rainbow trout were intraperitoneally transplanted into newly hatched sterile triploid masu salmon. Transplanted trout spermatogonia underwent spermatogenesis and oogenesis in male and female recipients, respectively. At 2 years after transplantation, triploid salmon recipients only produced trout sperm and eggs. With use of these salmon as parents, we successfully produced only donor-derived trout offspring. Thus, by transplanting cryopreserved spermatogonia into sterile xenogeneic recipients, we can generate individuals of a threatened species.

  15. Fuzzy modelling of Atlantic salmon physical habitat

    Science.gov (United States)

    St-Hilaire, André; Mocq, Julien; Cunjak, Richard

    2015-04-01

    Fish habitat models typically attempt to quantify the amount of available river habitat for a given fish species for various flow and hydraulic conditions. To achieve this, information on the preferred range of values of key physical habitat variables (e.g. water level, velocity, substrate diameter) for the targeted fishs pecies need to be modelled. In this context, we developed several habitat suitability indices sets for three Atlantic salmon life stages (young-of-the-year (YOY), parr, spawning adults) with the help of fuzzy logic modeling. Using the knowledge of twenty-seven experts, from both sides of the Atlantic Ocean, we defined fuzzy sets of four variables (depth, substrate size, velocity and Habitat Suitability Index, or HSI) and associated fuzzy rules. When applied to the Romaine River (Canada), median curves of standardized Weighted Usable Area (WUA) were calculated and a confidence interval was obtained by bootstrap resampling. Despite the large range of WUA covered by the expert WUA curves, confidence intervals were relatively narrow: an average width of 0.095 (on a scale of 0 to 1) for spawning habitat, 0.155 for parr rearing habitat and 0.160 for YOY rearing habitat. When considering an environmental flow value corresponding to 90% of the maximum reached by WUA curve, results seem acceptable for the Romaine River. Generally, this proposed fuzzy logic method seems suitable to model habitat availability for the three life stages, while also providing an estimate of uncertainty in salmon preferences.

  16. Salmon River Habitat Enhancement, 1984 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Konopacky, Richard C.

    1986-04-01

    This report has four volumes: a Tribal project annual report (Part 1) and three reports (Parts 2, 3, and 4) prepared for the Tribes by their engineering subcontractor. The Tribal project annual report contains reports for four subprojects within Project 83-359. Subproject I involved habitat and fish inventories in Bear Valley Creek, Valley County, Idaho that will be used to evaluate responses to ongoing habitat enhancement. Subproject II is the coordination/planning activities of the Project Leader in relation to other BPA-funded habitat enhancement projects that have or will occur within the traditional Treaty (Fort Bridger Treaty of 1868) fishing areas of the Shoshone-Bannock Tribes, Fort Hall Reservation, Idaho. Subproject III involved habitat and fish inventories (pretreatment) and habitat problem identification on the Yankee Fork of the Salmon River (including Jordan Creek). Subproject IV during 1985 involved habitat problem identification in the East Fork of the Salmon River and habitat and fish inventories (pretreatment) in Herd Creek, a tributary to the East Fork.

  17. The influence of fall-spawning coho salmon (Oncorhynchus kisutch) on growth and production of juvenile coho salmon rearing in beaver ponds on the Copper River Delta, Alaska.

    Science.gov (United States)

    Dirk W. Lang; Gordon H. Reeves; James D. Hall; Mark S. Wipfli

    2006-01-01

    This study examined the influence of fall-spawning coho salmon (Oncorhynchrcs kisutch) on the density, growth rate, body condition, and survival to outmigration of juvenile coho salmon on the Copper River Delta, Alaska, USA. During the fall of 1999 and 2000, fish rearing in beaver ponds that received spawning salmon were compared with fish from...

  18. Evaluation of the Contribution of Fall Chinook Salmon Reared at Columbia River Hatcheries to the Pacific Salmon Fisheries, Appendix, 1989 Final Report.

    Energy Technology Data Exchange (ETDEWEB)

    Vreeland, Robert R.

    1989-10-01

    This document contains 43 appendices for the Evaluation of the Contribution of Fall Chinook Salmon Reared at Columbia River Hatcheries to the Pacific Salmon Fisheries'' report. This study was initiated to determine the distribution, contribution, and value of artificially propagated fall Chinook Salmon from the Columbia River.

  19. In situ localisation of major histocompatibility complex class I and class II and CD8 positive cells in infectious salmon anaemia virus (ISAV)-infected Atlantic salmon

    DEFF Research Database (Denmark)

    Hetland, Dyveke Lem; Jørgensen, Sven Martin; Skjødt, Karsten

    2010-01-01

    It is assumed that the mobilisation of a strong cellular immune response is important for the survival of Atlantic salmon infected with infectious salmon anaemia virus (ISAV). In this study, the characterisation of immune cell populations in tissues of non-ISAV infected Atlantic salmon and during...

  20. AFSC/ABL: Adult Pink Salmon Predation in Prince William Sound and Southeast Alaska, 2009-2011

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The project objectives were to assess potential salmon predation impact on juvenile salmon and herring by: (1) comparing diets of adult pink salmon during their...

  1. Disruptive technology and medical librarians

    National Research Council Canada - National Science Library

    Cooper, I Diane

    2015-01-01

    ... has also been disrupted by technology. In our town, we used to have an afternoon newspaper. The reporters were competent; the managers worked hard. My father looked forward to reading the evening paper after coming home from work. But the newspaper industry was disrupted by technology, television. Dad's afternoon paper quit publishing, as newspapers...

  2. Disrupting Ethnography through Rhizoanalysis

    Directory of Open Access Journals (Sweden)

    Diana Masny

    2014-10-01

    Full Text Available This article interrogates principles of ethnography in education proposed by Mills and Morton: raw tellings, analytic pattern, vignette and empathy. This article adopts a position that is uncomfortable, unconventional and interesting. It involves a deterritorialization/ rupture of ethnography in education in order to reterritorialize a different concept: rhizoanalysis, a way to position theory and data that is multilayered, complex and messy. Rhizoanalysis, the main focus of this article is not a method. It is an approach to research conditioned by a reality in which Deleuze and Guattari disrupt representation, interpretation and subjectivity. In this article, Multiple Literacies Theory, a theoretical and practical framework, becomes a lens to examine a rhizomatic study of a Korean family recently arrived to Australia and attending English as a second language classes. Observations and interviews recorded the daily lives of the family. The vignettes were selected by reading data intensively and immanently through a process of palpation, an innovative approach to educational research. Rhizoanalysis proposes to abandon the given and invent different ways of thinking about and doing research and what might happen when reading data differently, intensively and immanently, through Multiple Literacies Theory. Rhizoanalysis, a game-changer in the way research can be conducted, affords a different lens to tackle issues in education through research.

  3. Infectious salmon anaemia virus replication and induction of alpha interferon in Atlantic salmon erythrocytes

    Directory of Open Access Journals (Sweden)

    Groman David B

    2008-02-01

    Full Text Available Abstract Background Infectious salmon anaemia (ISA virus (ISAV, which causes ISA in marine-farmed Atlantic salmon, is an orthomyxovirus belonging to the genus Isavirus, family Orthomyxoviridae. ISAV agglutinates erythrocytes of several fish species and it is generally accepted that the ISAV receptor destroying enzyme dissolves this haemagglutination except for Atlantic salmon erythrocytes. Recent work indicates that ISAV isolates that are able to elute from Atlantic salmon erythrocytes cause low mortality in challenge experiments using Atlantic salmon. Previous work on ISAV-induced haemagglutination using the highly pathogenic ISAV strain NBISA01 and the low pathogenic ISAV strain RPC/NB-04-0851, showed endocytosis of NBISA01 but not RPC/NB-04-0851. Real-time RT-PCR was used to assess the viral RNA levels in the ISAV-induced haemagglutination reaction samples, and we observed a slight increase in viral RNA transcripts by 36 hours in the haemagglutination reaction with NBISA01 virus when the experiment was terminated. However, a longer sampling interval was considered necessary to confirm ISAV replication in fish erythrocytes and to determine if the infected cells mounted any innate immune response. This study examined the possible ISAV replication and Type I interferon (IFN system gene induction in Atlantic salmon erythrocytes following ISAV haemagglutination. Results Haemagglutination assays were performed using Atlantic salmon erythrocytes and one haemagglutination unit of the two ISAV strains, NBISA01 and RPC/NB-04-0851, of differing genotypes and pathogenicities. Haemagglutination induced by the highly pathogenic NBISA01 but not the low pathogenic RPC/NB-04-0851 resulted in productive infection as evidenced by increased ISAV segment 8 transcripts and increase in the median tissue culture infectious dose (TCID50 by 5 days of incubation. Moreover, reverse transcription (RT quantitative PCR used to compare mRNA levels of key Type I IFN system

  4. Predation of Karluk River sockeye salmon by coho salmon and char

    Science.gov (United States)

    McIntyre, J.D.; Reisenbichler, R.R.; Emlen, J.M.; Wilmot, R.L.; Finn, J.E.

    1988-01-01

    The number of sockeye salmon, Oncorhynchus nerka, in Alaska's Karluk River (Fig. 1) declined from millions to thousands during the early part of the present century. Rounsefell (1958) discussed alternative explanations for the decline including a general loss offertility ofthe system as the number of salmon carcasses declined, competition, overfishing, subtle changes in climate, and predation; he concluded that the combined effect of predation and fishing was the most probable explanation. Later, Van Cleave and Bevan (1973) suggested that the weir constructed in the river each year to facilitate counting the fish as they entered the system was the most probable cause ofthe decline. Itprevented free movement of both adults and juveniles in the river. All of these hypotheses remain as potential explanations for the decline

  5. Global change in the trophic functioning of marine food webs

    DEFF Research Database (Denmark)

    Maureaud, Aurore; Gascuel, Didier; Colléter, Mathieu

    2017-01-01

    The development of fisheries in the oceans, and other human drivers such as climate warming, have led to changes in species abundance, assemblages, trophic interactions, and ultimately in the functioning of marine food webs. Here, using a trophodynamic approach and global databases of catches...... and life history traits of marine species, we tested the hypothesis that anthropogenic ecological impacts may have led to changes in the global parameters defining the transfers of biomass within the food web. First, we developed two indicators to assess such changes: the Time Cumulated Indicator (TCI......) measuring the residence time of biomass within the food web, and the Efficiency Cumulated Indicator (ECI) quantifying the fraction of secondary production reaching the top of the trophic chain. Then, we assessed, at the large marine ecosystem scale, the worldwide change of these two indicators over the 1950...

  6. Trait-mediated trophic interactions: is foraging theory keeping up?

    Science.gov (United States)

    Railsback, Steven F; Harvey, Bret C

    2013-02-01

    Many ecologists believe that there is a lack of foraging theory that works in community contexts, for populations of unique individuals each making trade-offs between food and risk that are subject to feedbacks from behavior of others. Such theory is necessary to reproduce the trait-mediated trophic interactions now recognized as widespread and strong. Game theory can address feedbacks but does not provide foraging theory for unique individuals in variable environments. 'State- and prediction-based theory' (SPT) is a new approach that combines existing trade-off methods with routine updating: individuals regularly predict future food availability and risk from current conditions to optimize a fitness measure. SPT can reproduce a variety of realistic foraging behaviors and trait-mediated trophic interactions with feedbacks, even when the environment is unpredictable. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Climate change impact on Balearic shearwater through a trophic cascade.

    Science.gov (United States)

    Luczak, C; Beaugrand, G; Jaffré, M; Lenoir, S

    2011-10-23

    A recent study showed that a critically endangered migratory predator species, the Balearic shearwater Puffinus mauretanicus, rapidly expanded northwards in northeast Atlantic waters after the mid-1990s. As a significant positive correlation was found between the long-term changes in the abundance of this seabird and sea temperature around the British Isles, it was hypothesized that the link between the biogeographic shift and temperature occurred through the food web. Here, we test this conjecture and reveal concomitant changes in a regional index of sea temperature, plankton (total calanoid copepod), fish prey (anchovy and sardine) and the Balearic shearwater for the period 1980-2003. All three trophic levels exhibit a significant shift detected between 1994 and 1996. Our findings therefore support the assertion of both a direct and an indirect effect of climate change on the spatial distribution of post-breeding Balearic shearwater through a trophic cascade.

  8. Trophic magnification of organic chemicals: A global synthesis

    Science.gov (United States)

    Walters, W. David; Jardine, T.D.; Cade, Brian S.; Kidd, K.A.; Muir, D.C.G.; Leipzig-Scott, Peter C.

    2016-01-01

    Production of organic chemicals (OCs) is increasing exponentially, and some OCs biomagnify through food webs to potentially toxic levels. Biomagnification under field conditions is best described by trophic magnification factors (TMFs; per trophic level change in log-concentration of a chemical) which have been measured for more than two decades. Syntheses of TMF behavior relative to chemical traits and ecosystem properties are lacking. We analyzed >1500 TMFs to identify OCs predisposed to biomagnify and to assess ecosystem vulnerability. The highest TMFs were for OCs that are slowly metabolized by animals (metabolic rate kM  0.2 day–1). This probabilistic model provides a new global tool for screening existing and new OCs for their biomagnification potential.

  9. Comparison of contaminants from different trophic levels and ecosystems

    DEFF Research Database (Denmark)

    Dietz, R.; Riget, F.; Cleemann, M.

    2000-01-01

    ecosystems. Of the nine compounds presented, seven (Cd, Hg, Se, Sigma PCB, Sigma DDT, Sigma HCH, HCB) increased in concentration towards higher trophic levels. For these contaminants the concentrations in soil and aquatic sediment were in the same order of magnitude, whereas the concentrations in marine...... considerably less mercury but higher levels of Sigma PCB, Sigma DDT and HCB than other Arctic marine top consumers. (C) 2000 Elsevier Science B.V. All rights reserved....

  10. The trophic requirements of selected underwood species occurring in forests

    OpenAIRE

    Lasota Jarosław; Błońska Ewa; Wanic Tomasz; Zwydak Maciej

    2014-01-01

    The subject of this study were soil requirements of common woody shrubs, which may be part of the forest understory (Sorbus aucuparia L., Frangula alnus Mill., Corylus avellana L., Juniperus communis L., Padus avium Mill., Euonymus europaea L., Sambucus nigra L.). We focused on phytocenoses in the vicinity of natural forests in reserves and national parks of Polish lowlands and defined optimal types and subtypes of soil with trophic variations for each underwood species. The range of trophis...

  11. TROPHIC RELATIONS OF LADY BEETLES (COLEOPTERA, COCCINELLIDAE) OF THE URALS

    OpenAIRE

    Z. I. Tyumaseva; E. V. Guskova

    2016-01-01

    The article contains the study of the trophic relations of the lady beetles living in the Urals. The study allocates three ecological groups depending on the peculiarities of the beetles and larvae nutrition: phytophages, micetophages, and entomophages-predators. We have revealed 66 species of lady birds-predators and two species-phytophages: Subcoccinella vigintiquatuorpunctata (Linnaeus, 1758) and Bulaea lichatschovii (Hummel, 1827). In the group of obligatory micetophages in the Urals we r...

  12. Bacterial Chitin Hydrolysis in Two Lakes with Contrasting Trophic Statuses

    OpenAIRE

    Köllner, Krista E.; Carstens, Dörte; Keller, Esther; Vazquez, Francisco; Schubert, Carsten J.; Zeyer, Josef; Bürgmann, Helmut

    2012-01-01

    Chitin, which is a biopolymer of the amino sugar glucosamine (GlcN), is highly abundant in aquatic ecosystems, and its degradation is assigned a key role in the recycling of carbon and nitrogen. In order to study the significance of chitin decomposition in two temperate freshwater lakes with contrasting trophic and redox conditions, we measured the turnover rate of the chitin analog methylumbelliferyl-N,N′-diacetylchitobioside (MUF-DC) and the presence of chitinase (chiA) genes in zooplankton...

  13. An approach to salmon farming in Norway : a future for land based salmon farming?

    OpenAIRE

    Tvete, Anders

    2016-01-01

    The aim of this thesis is to give an overview over the salmon farming industry in Norway. It presents some theory around production- and investment costs associated with land basedand sea based fish farming, as well as challenges around environmental issues, technology, fish feed etc. Several production concepts such as open cages in the sea, cages offshore, closed operations in the sea, both exposed and protected and land based production sites are available today, and the cha...

  14. Phenological sensitivity to climate across taxa and trophic levels.

    Science.gov (United States)

    Thackeray, Stephen J; Henrys, Peter A; Hemming, Deborah; Bell, James R; Botham, Marc S; Burthe, Sarah; Helaouet, Pierre; Johns, David G; Jones, Ian D; Leech, David I; Mackay, Eleanor B; Massimino, Dario; Atkinson, Sian; Bacon, Philip J; Brereton, Tom M; Carvalho, Laurence; Clutton-Brock, Tim H; Duck, Callan; Edwards, Martin; Elliott, J Malcolm; Hall, Stephen J G; Harrington, Richard; Pearce-Higgins, James W; Høye, Toke T; Kruuk, Loeske E B; Pemberton, Josephine M; Sparks, Tim H; Thompson, Paul M; White, Ian; Winfield, Ian J; Wanless, Sarah

    2016-07-14

    Differences in phenological responses to climate change among species can desynchronise ecological interactions and thereby threaten ecosystem function. To assess these threats, we must quantify the relative impact of climate change on species at different trophic levels. Here, we apply a Climate Sensitivity Profile approach to 10,003 terrestrial and aquatic phenological data sets, spatially matched to temperature and precipitation data, to quantify variation in climate sensitivity. The direction, magnitude and timing of climate sensitivity varied markedly among organisms within taxonomic and trophic groups. Despite this variability, we detected systematic variation in the direction and magnitude of phenological climate sensitivity. Secondary consumers showed consistently lower climate sensitivity than other groups. We used mid-century climate change projections to estimate that the timing of phenological events could change more for primary consumers than for species in other trophic levels (6.2 versus 2.5-2.9 days earlier on average), with substantial taxonomic variation (1.1-14.8 days earlier on average).

  15. Trophic transfer of metal-based nanoparticles in aquatic environments

    DEFF Research Database (Denmark)

    Tangaa, Stine Rosendal; Selck, Henriette; Winther-Nielsen, Margrethe

    2016-01-01

    Metal-containing engineered nanoparticles (Me-ENPs) are used in a wide range of products including inks, plastics, personal care products, clothing and electronic devices. The release of Me-ENPs has been demonstrated from some products, and thus, particles are likely to enter the aquatic environm......Metal-containing engineered nanoparticles (Me-ENPs) are used in a wide range of products including inks, plastics, personal care products, clothing and electronic devices. The release of Me-ENPs has been demonstrated from some products, and thus, particles are likely to enter the aquatic...... environment where they have been shown to be taken up by a variety of species. Therefore, there is a possibility that Me-ENPs will enter and pass through aquatic food webs, but research on this topic is limited. In this tutorial review, we discuss the factors contributing to trophic transfer of Me......-ENPs, and where this information is scarce, we utilize the existing literature on aqueous metal trophic transfer as a potential starting point for greater mechanistic insight and for setting directions for future studies. We identify four key factors affecting trophic transfer of Me-ENPs: (1) environmental...

  16. Influence of plant antibiosis through four trophic levels.

    Science.gov (United States)

    Orr, D B; Boethel, D J

    1986-09-01

    The effects of an insect herbivore-resistant soybean genotype on relationships between four levels of a trophic system were examined in the laboratory using both greenhouse and field-grown plants. Pre-imaginal development of the predatory pentatomid, Podisus maculiventris (Say), was affected by soybean antibiosis in a manner similar to that of its lepidopteran prey, Pseudoplusia includens (Walker). Pre-imaginal development time was increased, and cumulative weight gain tended to be reduced on both greenhouse and field-grown resistant foliage; although mortality was increased on greenhouse-grown resistant foliage, it appeared unchanged on field-grown foliage. Reproductive capacity of P. maculiventris reared on P. includens larvae that were fed resistant soybean generally was unaffected, although peak progeny production was delayed and extended slightly. Pre-imaginal development and adult emergence of the egg parasitoid Telenomus podisi Ashmead from eggs of P. maculiventris reared on P. includens larvae that were fed resistant soybean were unaffected. However, the overall reproductive capabilities of this parasitoid were reduced. Our results demonstrate that plant antibiosis can influence the biology of organisms over four trophic levels, thus documenting a relationship heretofore undescribed. Determination of the final outcome of the interaction between plant resistance and biological control is difficult. The four trophic level model reported in this study further illustrates the complexity which hinhers a general understanding of these interactions.

  17. Unpacking brown food-webs: Animal trophic identity reflects rampant microbivory.

    Science.gov (United States)

    Steffan, Shawn A; Chikaraishi, Yoshito; Dharampal, Prarthana S; Pauli, Jonathan N; Guédot, Christelle; Ohkouchi, Naohiko

    2017-05-01

    Detritivory is the dominant trophic paradigm in most terrestrial, aquatic, and marine ecosystems, yet accurate measurement of consumer trophic position within detrital (="brown") food webs has remained unresolved. Measurement of detritivore trophic position is complicated by the fact that detritus is suffused with microbes, creating a detrital complex of living and nonliving biomass. Given that microbes and metazoans are trophic analogues of each other, animals feeding on detrital complexes are ingesting other detritivores (microbes), which should elevate metazoan trophic position and should be rampant within brown food webs. We tested these hypotheses using isotopic (15N) analyses of amino acids extracted from wild and laboratory-cultured consumers. Vertebrate (fish) and invertebrate detritivores (beetles and moths) were reared on detritus, with and without microbial colonization. In the field, detritivorous animal specimens were collected and analyzed to compare trophic identities among laboratory-reared and free-roaming detritivores. When colonized by bacteria or fungi, the trophic positions of detrital complexes increased significantly over time. The magnitude of trophic inflation was mediated by the extent of microbial consumption of detrital substrates. When detrital complexes were fed to vertebrate and invertebrate animals, the consumers registered similar degrees of trophic inflation, albeit one trophic level higher than their diets. The wild-collected detritivore fauna in our study exhibited significantly elevated trophic positions. Our findings suggest that the trophic positions of detrital complexes rise predictably as microbes convert nonliving organic matter into living microbial biomass. Animals consuming such detrital complexes exhibit similar trophic inflation, directly attributable to the assimilation of microbe-derived amino acids. Our data demonstrate that detritivorous microbes elevate metazoan trophic position, suggesting that detritivory among

  18. Pink Salmon 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 PINK SALMON contained in the StreamNet database. This feature class was created based on linear event...

  19. AFSC/FMA/Salmon Genetics From Observer Speimens

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Genetic data of salmon bycatch samples collected by fisheries observers are used for mixed-stock analyses to determine geographic region of origin. This work is done...

  20. Isotopes - Recolonization of the Cedar River, WA by Pacific salmon

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The objective of this study is to quantify population, community, and ecosystem level changes as a result of salmon recolonization of the Cedar River, WA above...

  1. Broodyear data - Snake River sockeye salmon captive propagation

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gene rescue captive broodstock program was established for ESA-listed endangered Snake River sockeye salmon from Redfish Lake, Idaho. The program has consisted of...

  2. Growth data - Snake River sockeye salmon captive propagation

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gene rescue captive broodstock program was established for ESA-listed endangered Snake River sockeye salmon from Redfish Lake, Idaho. The program has consisted of...

  3. Production data - Snake River sockeye salmon captive propagation

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gene rescue captive broodstock program was established for ESA-listed endangered Snake River sockeye salmon from Redfish Lake, Idaho. The program has consisted of...

  4. Juvenile Salmon Scale Data - Ocean Survival of Salmonids

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A study to evaluate the role of changing ocean conditions on growth and survival of juvenile salmon from the Columbia River basin as they enter the Columbia River...

  5. Chum Salmon 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 CHUM SALMON contained in the StreamNet database. This feature class was created based on linear event...

  6. Sockeye Salmon 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 SOCKEYE SALMON contained in the StreamNet database. This feature class was created based on linear...

  7. Coho Salmon 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 COHO SALMON contained in the StreamNet database. This feature class was created based on linear event...

  8. Benthic monitoring of salmon farms in Norway using foraminiferal metabarcoding

    DEFF Research Database (Denmark)

    Pawlowski, Jan; Esling, Philippe; Lejzerowicz, Franck

    2016-01-01

    The rapid growth of the salmon industry necessitates the development of fast and accurate tools to assess its environmental impact. Macrobenthic monitoring is commonly used to measure the impact of organic enrichment associated with salmon farm activities. However, classical benthic monitoring can...... of macrofauna-based benthic monitoring. Here, we tested the application of foraminiferal metabarcoding to benthic monitoring of salmon farms in Norway. We analysed 140 samples of eDNA and environmental RNA (eRNA) extracted from surface sediment samples collected at 4 salmon farming sites in Norway. We sequenced...... appears to be a promising alternative to classical benthic monitoring, providing a solution to the morpho-taxonomic bottleneck of macrofaunal surveys....

  9. Surveys on Gyrodactylus parasites onwild Atlantic salmon in Denmark

    DEFF Research Database (Denmark)

    Jørgensen, Louise von Gersdorff; Heinecke, Rasmus Demuth; Buchmann, Kurt

    Gyrodactylus salaris is a monogenean ectoparasite parasitizing salmonids in freshwater. This parasite is highly pathogenic to both Norwegian and Scottish salmon and has decimated the salmon populations in 45 Norwegian rivers after anthropogenic transfer from Sweden. G. salaris has also been found...... on several occasions in Danish rainbow trout farms but has never been recorded as a pathogenic parasite on Danish wild salmon. In the present study the occurrence of G. salaris and other Gyrodactylus parasites on wild Danish salmon fry and parr were monitored. Electrofishing was conducted in three river...... were examined for Gyrodactylus parasites under a dissection microscope. The location of each parasite was registered and each parasite was isolated for later morphological and genetic typing. The opisthaptor was separated from the body, fixed and mounted using Malmbergs fixative (ammonium picrate...

  10. AFSC/ABL: 2007-2013 Chinook Salmon Bycatch Sample

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A genetic analyses of samples from the Chinook salmon (Oncorhynchus tshawytscha) bycatch from the 2007-2013 Bering Sea-Aleutian Island and Gulf of Alaska trawl...

  11. Estimation of coho salmon escapement in the Ugashik lakes

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — From 26 July to 24 September 2002, hourly counts were conducted from counting towers to estimate the escapement of coho salmon Oncorhynchus kisutch into the Ugashik...

  12. Estimation of sockeye and coho salmon escapement in Mortensens creek

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — A fixed picket weir was operated on Mortensens Creek from 1 July to 26 October 2001. Coho salmon Onchorynchus kisutch was the most abundant species counted through...

  13. Financial analysis of commercial salmon fisheries: marine & inland fisheries

    National Research Council Canada - National Science Library

    2014-01-01

    ... in commercial and recreational fisheries. To estimate the financial inputs required for the BCIOM analysis, Counterpoint designed and deployed a financial analysis model of the commercial salmon fishery in which the commercial fishery...

  14. Light Experiment data - Snake River sockeye salmon captive propagation

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In the early 1990s, Redfish Lake sockeye salmon from the Sawtooth Basin in Idaho were on the brink of extinction, and they were listed as endangered under the US...

  15. Social Behavior - Snake River sockeye salmon captive propagation

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In the early 1990s, Redfish Lake sockeye salmon from the Sawtooth Basin in Idaho were on the brink of extinction, and they were listed as endangered under the US...

  16. The salmon bears: giants of the great bear rainforest

    National Research Council Canada - National Science Library

    McAllister, I; Read, N

    2010-01-01

    The Salmon Bears explores the delicate balance that exists between the grizzly, black and spirit bears of the Great Bear Rainforest and their natural environment on the central coast of British Columbia...

  17. Chinook Bycatch - Contemporary Salmon Genetic Stock Composition Estimates

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The purpose of this project is to measure and monitor impacts on ESA-listed populations and to estimate overall Chinook salmon stock composition in bycatch...

  18. Pacific salmon and the coalescent effective population size.

    Science.gov (United States)

    Cenik, Can; Wakeley, John

    2010-09-27

    Pacific salmon include several species that are both commercially important and endangered. Understanding the causes of loss in genetic variation is essential for designing better conservation strategies. Here we use a coalescent approach to analyze a model of the complex life history of salmon, and derive the coalescent effective population (CES). With the aid of Kronecker products and a convergence theorem for Markov chains with two time scales, we derive a simple formula for the CES and thereby establish its existence. Our results may be used to address important questions regarding salmon biology, in particular about the loss of genetic variation. To illustrate the utility of our approach, we consider the effects of fluctuations in population size over time. Our analysis enables the application of several tools of coalescent theory to the case of salmon.

  19. Pacific salmon and the coalescent effective population size.

    Directory of Open Access Journals (Sweden)

    Can Cenik

    Full Text Available Pacific salmon include several species that are both commercially important and endangered. Understanding the causes of loss in genetic variation is essential for designing better conservation strategies. Here we use a coalescent approach to analyze a model of the complex life history of salmon, and derive the coalescent effective population (CES. With the aid of Kronecker products and a convergence theorem for Markov chains with two time scales, we derive a simple formula for the CES and thereby establish its existence. Our results may be used to address important questions regarding salmon biology, in particular about the loss of genetic variation. To illustrate the utility of our approach, we consider the effects of fluctuations in population size over time. Our analysis enables the application of several tools of coalescent theory to the case of salmon.

  20. 1992 Columbia River Salmon Flow Measures Options Analysis/EIS.

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    This Options Analysis/Environmental Impact Statement (OA/EIS) identifies, presents effects of, and evaluates the potential options for changing instream flow levels in efforts to increase salmon populations in the lower Columbia and Snake rivers. The potential actions would be implemented during 1992 to benefit juvenile and adult salmon during migration through eight run-of-river reservoirs. The Corps of Engineers (Corps) prepared this document in cooperation with the Bonneville Power Administration and the Bureau of Reclamation. The US Fish and Wildlife Service (FSWS) is a participating agency. The text and appendices of the document describe the characteristics of 10 Federal projects and one private water development project in the Columbia River drainage basin. Present and potential operation of these projects and their effects on the salmon that spawn and rear in the Columbia and Snake River System are presented. The life history, status, and response of Pacific salmon to current environmental conditions are described.

  1. Air flotation treatment of salmon processing waste water

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This paper discusses methods for the reduction of the pollution strength of salmon processing waste water. Past research has indicated the success of air pressure...

  2. Costs of climate change: Economic value of Yakima River salmon

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, D.M.; Shankle, S.A.; Scott, M.J.; Neitzel, D.A.; Chatters, J.C.

    1992-07-01

    This work resulted from a continuing multidisciplinary analysis of species preservation and global change. The paper explores the economic cost of a potential regional warming as it affects one Pacific Northwest natural resource, the spring chinook salmon (Oncorhynchus tshcawytscha). Climate change and planned habitat improvements impact the production and economic value of soling chinook salmon of the Yakima River tributary of the Columbia River in eastern Washington. The paper presents a derivation of the total economic value of a chinook salmon, which includes the summation of the existence, commercial, recreational, and capital values of the fish. When currently available commercial, recreational, existence, and capital values for chinook salmon were applied to estimated population changes, the estimated change in the economic value per fish associated with reduction of one fish run proved significant.

  3. Why are not there more Atlantic salmon (Salmo salar)

    Energy Technology Data Exchange (ETDEWEB)

    Parrish, D. L. [Vermont Univ., School of Natural Resources, Vermont Cooperative Fish and Wildlife Research Unit, Burlington, VT (United States); Behnke, R. J. [Colorado State Univ., Dept. of Fishery and Wildlife Biology, Fort Collins, CO (United States); Gephard, S. R. [Connecticut Dept. of Environmnetal Protection, Fisheries Div., Old Lyme, CT (United States); McCormick, S. D. [Anadromous Fish Research Center, USGS/Biological Resources Div., Turners Falls, MA (United States); Reeves, G. H. [USDA Forest Service, Corvallis, OR (United States)

    1998-12-31

    The causes of decline and extirpation of salmon on a global scale are investigated. In some cases single factors such as dams, pollution and dewatering, increased density of humans near salmon rivers, overfishing, changes in ocean conditions or intensive aquaculture could be identified as likely causes. The available evidence is not sufficient to link cause and effect for most declines because they are the result of multiple factors, and data that would help to discriminate factors on scales of space or time are lacking. For this reason, it is not possible to allocate the proportional impact of multiple factors that contribute to the the demise of salmon populations. More rigorous methodologies, including more effective sampling techniques, testing of multiple effects integrated across space and time, and adaptive management are needed to account for the continuing decline of salmon.

  4. AFSC/ABL: Karluk sockeye salmon scale time series

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — To better understand how density-dependent growth of ocean-dwelling Pacific salmon varied with climate and population dynamics, we examined the marine growth of...

  5. Spawning data - Snake River sockeye salmon captive propagation

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gene rescue captive broodstock program was established for ESA-listed endangered Snake River sockeye salmon from Redfish Lake, Idaho. The program has consisted of...

  6. AFSC/ABL: Movements of Yukon River Chinook salmon

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Upriver movements were determined for Chinook salmon Oncorhynchus tshawytscha returning to the Yukon River, a large, relatively pristine river basin. A total of...

  7. AFSC/ABL: Ugashik sockeye salmon scale time series

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A time series of scale samples (1956 b?? 2002) collected from adult sockeye salmon returning to Ugashik River were retrieved from the Alaska Department of Fish and...

  8. AFSC/ABL: Naknek sockeye salmon scale time series

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A time series of scale samples (1956 2002) collected from adult sockeye salmon returning to Naknek River were retrieved from the Alaska Department of Fish and Game....

  9. Fish Health data - Snake River sockeye salmon captive propagation

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In the early 1990s, Redfish Lake sockeye salmon from the Sawtooth Basin in Idaho were on the brink of extinction, and they were listed as endangered under the US...

  10. Near coastal ocean attributes of salmon - Ocean Survival of Salmonids

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A study to evaluate the role of changing ocean conditions on growth and survival of juvenile salmon from the Columbia River basin as they enter the Columbia River...

  11. Fish Culture data - Snake River sockeye salmon captive propagation

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gene rescue captive broodstock program was established for ESA-listed endangered Snake River sockeye salmon from Redfish Lake, Idaho. The program has consisted of...

  12. Performance of salmon fishery portfolios across western North America.

    Science.gov (United States)

    Griffiths, Jennifer R; Schindler, Daniel E; Armstrong, Jonathan B; Scheuerell, Mark D; Whited, Diane C; Clark, Robert A; Hilborn, Ray; Holt, Carrie A; Lindley, Steven T; Stanford, Jack A; Volk, Eric C

    2014-12-01

    Quantifying the variability in the delivery of ecosystem services across the landscape can be used to set appropriate management targets, evaluate resilience and target conservation efforts. Ecosystem functions and services may exhibit portfolio-type dynamics, whereby diversity within lower levels promotes stability at more aggregated levels. Portfolio theory provides a framework to characterize the relative performance among ecosystems and the processes that drive differences in performance. We assessed Pacific salmon Oncorhynchus spp. portfolio performance across their native latitudinal range focusing on the reliability of salmon returns as a metric with which to assess the function of salmon ecosystems and their services to humans. We used the Sharpe ratio (e.g. the size of the total salmon return to the portfolio relative to its variability (risk)) to evaluate the performance of Chinook and sockeye salmon portfolios across the west coast of North America. We evaluated the effects on portfolio performance from the variance of and covariance among salmon returns within each portfolio, and the association between portfolio performance and watershed attributes. We found a positive latitudinal trend in the risk-adjusted performance of Chinook and sockeye salmon portfolios that also correlated negatively with anthropogenic impact on watersheds (e.g. dams and land-use change). High-latitude Chinook salmon portfolios were on average 2·5 times more reliable, and their portfolio risk was mainly due to low variance in the individual assets. Sockeye salmon portfolios were also more reliable at higher latitudes, but sources of risk varied among the highest performing portfolios. Synthesis and applications. Portfolio theory provides a straightforward method for characterizing the resilience of salmon ecosystems and their services. Natural variability in portfolio performance among undeveloped watersheds provides a benchmark for restoration efforts. Locally and regionally

  13. Reef Fishes at All Trophic Levels Respond Positively to Effective Marine Protected Areas.

    Directory of Open Access Journals (Sweden)

    German A Soler

    Full Text Available Marine Protected Areas (MPAs offer a unique opportunity to test the assumption that fishing pressure affects some trophic groups more than others. Removal of larger predators through fishing is often suggested to have positive flow-on effects for some lower trophic groups, in which case protection from fishing should result in suppression of lower trophic groups as predator populations recover. We tested this by assessing differences in the trophic structure of reef fish communities associated with 79 MPAs and open-access sites worldwide, using a standardised quantitative dataset on reef fish community structure. The biomass of all major trophic groups (higher carnivores, benthic carnivores, planktivores and herbivores was significantly greater (by 40% - 200% in effective no-take MPAs relative to fished open-access areas. This effect was most pronounced for individuals in large size classes, but with no size class of any trophic group showing signs of depressed biomass in MPAs, as predicted from higher predator abundance. Thus, greater biomass in effective MPAs implies that exploitation on shallow rocky and coral reefs negatively affects biomass of all fish trophic groups and size classes. These direct effects of fishing on trophic structure appear stronger than any top down effects on lower trophic levels that would be imposed by intact predator populations. We propose that exploitation affects fish assemblages at all trophic levels, and that local ecosystem function is generally modified by fishing.

  14. Reef Fishes at All Trophic Levels Respond Positively to Effective Marine Protected Areas.

    Science.gov (United States)

    Soler, German A; Edgar, Graham J; Thomson, Russell J; Kininmonth, Stuart; Campbell, Stuart J; Dawson, Terence P; Barrett, Neville S; Bernard, Anthony T F; Galván, David E; Willis, Trevor J; Alexander, Timothy J; Stuart-Smith, Rick D

    2015-01-01

    Marine Protected Areas (MPAs) offer a unique opportunity to test the assumption that fishing pressure affects some trophic groups more than others. Removal of larger predators through fishing is often suggested to have positive flow-on effects for some lower trophic groups, in which case protection from fishing should result in suppression of lower trophic groups as predator populations recover. We tested this by assessing differences in the trophic structure of reef fish communities associated with 79 MPAs and open-access sites worldwide, using a standardised quantitative dataset on reef fish community structure. The biomass of all major trophic groups (higher carnivores, benthic carnivores, planktivores and herbivores) was significantly greater (by 40% - 200%) in effective no-take MPAs relative to fished open-access areas. This effect was most pronounced for individuals in large size classes, but with no size class of any trophic group showing signs of depressed biomass in MPAs, as predicted from higher predator abundance. Thus, greater biomass in effective MPAs implies that exploitation on shallow rocky and coral reefs negatively affects biomass of all fish trophic groups and size classes. These direct effects of fishing on trophic structure appear stronger than any top down effects on lower trophic levels that would be imposed by intact predator populations. We propose that exploitation affects fish assemblages at all trophic levels, and that local ecosystem function is generally modified by fishing.

  15. GABAergic anxiolytic drug in water increases migration behaviour in salmon

    OpenAIRE

    Hellström, Gustav; Klaminder, Jonatan; Finn, Fia; Persson, Lo; Alanärä, Anders; Jonsson, Micael; Fick, Jerker; Brodin, Tomas

    2016-01-01

    Migration is an important life-history event in a wide range of taxa, yet many migrations are influenced by anthropogenic change. Although migration dynamics are extensively studied, the potential effects of environmental contaminants on migratory physiology are poorly understood. In this study we show that an anxiolytic drug in water can promote downward migratory behaviour of Atlantic salmon (Salmo salar) in both laboratory setting and in a natural river tributary. Exposing salmon smolt to ...

  16. Projected impacts of climate change on salmon habitat restoration

    OpenAIRE

    Battin, James; Wiley, Matthew W.; Mary H. Ruckelshaus; Palmer, Richard N.; Korb, Elizabeth; Bartz, Krista K.; Imaki, Hiroo

    2007-01-01

    Throughout the world, efforts are under way to restore watersheds, but restoration planning rarely accounts for future climate change. Using a series of linked models of climate, land cover, hydrology, and salmon population dynamics, we investigated the impacts of climate change on the effectiveness of proposed habitat restoration efforts designed to recover depleted Chinook salmon populations in a Pacific Northwest river basin. Model results indicate a large negative impact of climate change...

  17. Pacific salmon extinctions: quantifying lost and remaining diversity.

    Science.gov (United States)

    Gustafson, Richard G; Waples, Robin S; Myers, James M; Weitkamp, Laurie A; Bryant, Gregory J; Johnson, Orlay W; Hard, Jeffrey J

    2007-08-01

    Widespread population extirpations and the consequent loss of ecological, genetic, and life-history diversity can lead to extinction of evolutionarily significant units (ESUs) and species. We attempted to systematically enumerate extinct Pacific salmon populations and characterize lost ecological, life history, and genetic diversity types among six species of Pacific salmon (Chinook [Oncorhynchus tshawytscha], sockeye [O. nerka], coho [O. kisutch], chum [O. keta], and pink salmon [O. gorbuscha] and steelhead trout [O. mykiss]) from the western contiguous United States. We estimated that, collectively, 29% of nearly 1400 historical populations of these six species have been lost from the Pacific Northwest and California since Euro-American contact. Across all species there was a highly significant difference in the proportion of population extinctions between coastal (0.14 extinct) and interior (0.55 extinct) regions. Sockeye salmon (which typically rely on lacustrine habitats for rearing) and stream-maturing Chinook salmon (which stay in freshwater for many months prior to spawning) had significantly higher proportional population losses than other species and maturation types. Aggregate losses of major ecological, life-history, and genetic biodiversity components across all species were estimated at 33%, 15%, and 27%, respectively. Collectively, we believe these population extirpations represent a loss of between 16% and 30% of all historical ESUs in the study area. On the other hand, over two-thirds of historical Pacific salmon populations in this area persist, and considerable diversity remains at all scales. Because over one-third of the remaining populations belong to threatened or endangered species listed under the U.S. Endangered Species Act, it is apparent that a critical juncture has been reached in efforts to preserve what remains of Pacific salmon diversity. It is also evident that persistence of existing, and evolution of future, diversity will depend

  18. Pacific Salmon and the Coalescent Effective Population Size

    OpenAIRE

    Can Cenik; John Wakeley

    2010-01-01

    Pacific salmon include several species that are both commercially important and endangered. Understanding the causes of loss in genetic variation is essential for designing better conservation strategies. Here we use a coalescent approach to analyze a model of the complex life history of salmon, and derive the coalescent effective population (CES). With the aid of Kronecker products and a convergence theorem for Markov chains with two time scales, we derive a simple formula for the CES and th...

  19. Early trophic feeding for very low birth weight infants.

    Science.gov (United States)

    Bombell, Sarah; McGuire, William

    2009-07-08

    The introduction of enteral feeds for very low birth weight (VLBW) infants is often delayed due to concern that early introduction may not be tolerated and may increase the risk of necrotising enterocolitis. However, enteral fasting may diminish the functional adaptation of the immature gastrointestinal tract and prolong the need for parenteral nutrition with its attendant infectious and metabolic risks. Early trophic feeding, giving infants very small volumes of milk during the first week after birth, may promote intestinal maturation, enhance feeding tolerance and decrease time to reach full enteral feeding independently of parenteral nutrition. To determine the effect of early trophic feeding versus enteral fasting on feed tolerance, growth, and the incidence of necrotising enterocolitis, mortality and other morbidities in VLBW infants. The standard search strategy of the Cochrane Neonatal Group was used. Searches were made of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1, 2009), MEDLINE (1966 - February 2009), EMBASE (1980 - February 2009), CINAHL (1982 - February 2009), conference proceedings, and previous reviews. Randomised or quasi-randomised controlled trials that assessed the effects of early trophic feeding (milk volumes up to 24 ml/kg/day introduced before 96 hours postnatal age and continued until at least one week after birth) versus a comparable period of enteral fasting in VLBW infants. The standard methods of the Cochrane Neonatal Group were used, with separate evaluation of trial quality and data extraction by two review authors. Data were synthesised using a fixed effects model and reported using typical relative risk, typical risk difference and weighted mean difference. Nine trials, in which a total of 754 VLBW infants participated, were eligible for inclusion. These trials did not provide any evidence that early trophic feeding affected feed tolerance or growth rates in VLBW infants. Meta

  20. Trophic magnification factors: considerations of ecology, ecosystems, and study design.

    Science.gov (United States)

    Borgå, Katrine; Kidd, Karen A; Muir, Derek C G; Berglund, Olof; Conder, Jason M; Gobas, Frank A P C; Kucklick, John; Malm, Olaf; Powell, David E

    2012-01-01

    Recent reviews by researchers from academia, industry, and government have revealed that the criteria used by the Stockholm Convention on persistent organic pollutants under the United Nations Environment Programme are not always able to identify the actual bioaccumulative capacity of some substances, by use of chemical properties such as the octanol-water partitioning coefficient. Trophic magnification factors (TMFs) were suggested as a more reliable tool for bioaccumulation assessment of chemicals that have been in commerce long enough to be quantitatively measured in environmental samples. TMFs are increasingly used to quantify biomagnification and represent the average diet-to-consumer transfer of a chemical through food webs. They differ from biomagnification factors, which apply to individual species and can be highly variable between predator-prey combinations. The TMF is calculated from the slope of a regression between the chemical concentration and trophic level of organisms in the food web. The trophic level can be determined from stable N isotope ratios (δ(15) N). In this article, we give the background for the development of TMFs, identify and discuss impacts of ecosystem and ecological variables on their values, and discuss challenges and uncertainties associated with contaminant measurements and the use of δ(15) N for trophic level estimations. Recommendations are provided for experimental design, data treatment, and statistical analyses, including advice for users on reporting and interpreting TMF data. Interspecies intrinsic ecological and organismal properties such as thermoregulation, reproductive status, migration, and age, particularly among species at higher trophic levels with high contaminant concentrations, can influence the TMF (i.e., regression slope). Following recommendations herein for study design, empirical TMFs are likely to be useful for understanding the food web biomagnification potential of chemicals, where the target is to

  1. Antimicrobial multiresistance in bacteria isolated from freshwater Chilean salmon farms.

    Science.gov (United States)

    Mirand, Claudio D; Zemelman, Raul

    2002-07-03

    The intensive use of antimicrobial agents, mainly oxytetracycline, to prevent and control bacterial pathologies in Chilean salmon culture is a frequent practice. A total of 103 gram-negative oxytetracycline-resistant bacteria recovered from various sources of 4 Chilean freshwater salmon farms were identified and investigated for their susceptibility patterns to various antibacterial agents, by using an agar disk diffusion method. Antibacterial resistance patterns of isolates were not correlated with bacterial species or strain source. A high number of bacteria resistant to amoxicillin, ampicillin. erythromycin, and furazolidone, as well as an important frequency of bacterial resistance to florfenicol, chloramphenicol, cefotaxime and trimethoprim-sulfamethoxazole was found. On the contrary, the proportion of bacteria resistant to gentamicin, kanamycin, flumequine and enrofloxacin was rather low. Resistant microflora showed a high taxonomic variability and mainly consisted of non-fermenting bacteria (77.7%). These strains mainly belonged to the species Pseudomonas fluorescens (29), Aeromonas hydrophila (10), Stenotrophomonas maltophilia (6), isolated from salmon fingerlings, and Acinetobacter lwoffii (5) isolated from pelletized feed. The occurrence of simultaneous resistance to various antibacterials was frequent. We observe a high frequency of bacteria resistant to 6-10 antibacterials (74 strains), and antibiotic resistance index (ARI) values ranging from 0.38 to 0.48 for the four salmon farms studied. These results suggest that Chilean salmon farms might play a role as reservoirs of antibacterial multiresistant bacteria, thus prompting the necessity for a more restrictive attitude towards the intensive use of antibacterials in salmon farming.

  2. Resilient Salmon, Resilient Fisheries for British Columbia, Canada

    Directory of Open Access Journals (Sweden)

    Michael C. Healey

    2009-06-01

    Full Text Available Salmon are inherently resilient species. However, this resiliency has been undermined in British Columbia by a century of centralized, command-and-control management focused initially on maximizing yield and, more recently, on economic efficiency. Community and cultural resiliency have also been undermined, especially by the recent emphasis on economic efficiency, which has concentrated access in the hands of a few and has disenfranchised fishery-dependent communities. Recent declines in both salmon stocks and salmon prices have revealed the systemic failure of the current management system. If salmon and their fisheries are to become viable again, radically new management policies are needed. For the salmon species, the emphasis must shift from maximizing yield to restoring resilience; for salmon fisheries, the emphasis must shift from maximizing economic efficiency to maximizing community and cultural resilience. For the species, an approach is needed that integrates harvest management, habitat management, and habitat enhancement to sustain and enhance resilience. This is best achieved by giving fishing and aboriginal communities greater responsibility and authority to manage the fisheries on which they depend. Co-management arrangements that involve cooperative ownership of major multistock resources like the Fraser River and Skeena River fisheries and community-based quota management of smaller fisheries provide ways to put species conservation much more directly in the hands of the communities most dependent on the well-being and resilience of these fisheries.

  3. A highly redundant BAC library of Atlantic salmon (Salmo salar: an important tool for salmon projects

    Directory of Open Access Journals (Sweden)

    Koop Ben F

    2005-04-01

    Full Text Available Abstract Background As farming of Atlantic salmon is growing as an aquaculture enterprise, the need to identify the genomic mechanisms for specific traits is becoming more important in breeding and management of the animal. Traits of importance might be related to growth, disease resistance, food conversion efficiency, color or taste. To identify genomic regions responsible for specific traits, genomic large insert libraries have previously proven to be of crucial importance. These large insert libraries can be screened using gene or genetic markers in order to identify and map regions of interest. Furthermore, large-scale mapping can utilize highly redundant libraries in genome projects, and hence provide valuable data on the genome structure. Results Here we report the construction and characterization of a highly redundant bacterial artificial chromosome (BAC library constructed from a Norwegian aquaculture strain male of Atlantic salmon (Salmo salar. The library consists of a total number of 305 557 clones, in which approximately 299 000 are recombinants. The average insert size of the library is 188 kbp, representing 18-fold genome coverage. High-density filters each consisting of 18 432 clones spotted in duplicates have been produced for hybridization screening, and are publicly available 1. To characterize the library, 15 expressed sequence tags (ESTs derived overgos and 12 oligo sequences derived from microsatellite markers were used in hybridization screening of the complete BAC library. Secondary hybridizations with individual probes were performed for the clones detected. The BACs positive for the EST probes were fingerprinted and mapped into contigs, yielding an average of 3 contigs for each probe. Clones identified using genomic probes were PCR verified using microsatellite specific primers. Conclusion Identification of genes and genomic regions of interest is greatly aided by the availability of the CHORI-214 Atlantic salmon BAC

  4. 77 FR 75101 - Fisheries Off West Coast States; West Coast Salmon Fisheries; Amendment 17 to the Salmon Fishery...

    Science.gov (United States)

    2012-12-19

    ... approved Amendment 16 to the Salmon FMP. Amendment 16 established status determination criteria (SDC), and... a letter to the Council, dated December 11, 2011, NMFS detailed the disapproval of one SDC, the...

  5. Abundance and run timing of salmon in Blue Bill and Red Salmon Creeks, Izembek National Wildlife Refuge, 2005

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — A bi-directional fixed picket weir was installed and operated within Izembek National Wildlife Refuge on Red Salmon Creek (RS) from 26 June to 21 September and on...

  6. Diet, feeding patterns, and prey selection of subyearling Atlantic salmon (Salmo salar) and subyearling chinook salmon (Oncorhynchus tshawytscha) in a tributary of Lake Ontario

    Science.gov (United States)

    Johnson, J. H.; Nash, K. J.; Chiavelli, R. A.; DiRado, J. A.; Mackey, G. E.; Knight, J. R.; Diaz, A. R.

    2017-01-01

    Since juvenile Atlantic salmon (Salmo salar) and Chinook salmon (Oncorhynchus tshawytscha) occupy a similar habitat in Lake Ontario tributaries, we sought to determine the degree of diet similarity between these species in order to assess the potential for interspecific competition. Atlantic salmon, an historically important but currently extirpated component of the Lake Ontario fish community, are the focus of a bi-national restoration effort. Presently this effort includes the release of hatchery produced juvenile Atlantic salmon in Lake Ontario tributaries. These same tributaries support substantial numbers of naturally reproduced juvenile Pacific salmonids including Chinook salmon. Subyearling Atlantic salmon and subyearling Chinook salmon had significantly different diets during each of the three time periods examined. Atlantic salmon fed slightly more from the benthos than from the drift and consumed mainly chirononmids (47.0%) and ephemeropterans (21.1%). The diet of subyearling Chinook salmon was more closely associated with the drift and consisted mainly of chironomids (60.2%) and terrestrial invertebrates (16.0%). Low diet similarity between subyearling Atlantic salmon and subyearling Chinook salmon likely minimizes competitive interactions for food between these species in Lake Ontario tributaries. However, the availability of small prey such as chironomids which comprise over 50% of the diet of each species, soon after emergence, could constitute a short term resource limitation. To our knowledge this is the first study of interspecific diet associations between these two important salmonid species.

  7. Looking for sustainable solutions in salmon aquaculture

    Directory of Open Access Journals (Sweden)

    Jennifer Bailey

    2014-05-01

    Full Text Available Sustainable development poses highly complex issues for those who attempt to implement it. Using the Brundtland Commission’s definition of sustainable development as a vantage point, this article discusses the issues posed by the production of one kind of food, farmed Atlantic salmon, as a means of illustrating the complexity, interconnectedness and high-data requirements involved in assessing whether a given industry is sustainable. These issues are explored using the three commonly accepted aspects of sustainability – its environmental, social and economic aspects – and the dilemmas posed by the need to make the trade-offs necessary among these. It concludes by arguing that decisions of this complexity require complex and multiple decision-making structures and suggests four that are essential for the task.http://dx.doi.org/10.5324/eip.v8i1.1801

  8. Diphyllobothriasis Associated with Eating Raw Pacific Salmon

    Science.gov (United States)

    Yamada, Minoru; Nakamura-Uchiyama, Fukumi; Ohnishi, Kenji

    2009-01-01

    The incidence of human infection with the broad tapeworm Diphyllobothrium nihonkaiense has been increasing in urban areas of Japan and in European countries. D. nihonkaiense is morphologically similar to but genetically distinct from D. latum and exploits anadromous wild Pacific salmon as its second intermediate host. Clinical signs in humans include diarrhea and discharge of the strobila, which can be as long as 12 m. The natural life history and the geographic range of the tapeworm remain to be elucidated, but recent studies have indicated that the brown bear in the northern territories of the Pacific coast region is its natural final host. A recent surge of clinical cases highlights a change in the epidemiologic trend of this tapeworm disease from one of rural populations to a disease of urban populations worldwide who eat seafood as part of a healthy diet. PMID:19523283

  9. Trophic levels of fish species of commercial importance in the Colombian Caribbean

    Directory of Open Access Journals (Sweden)

    Camilo B García

    2011-09-01

    Full Text Available Ecological studies on commercial important fish species are of great value to support resource management issues. This study calculated trophic levels of those Colombian Caribbean fish species whose diet has been locally described. Usable diet data of 119 species resulted in 164 trophic level estimates. An ordinary regression model relating trophic level and fish size was formulated. The regression slope was positive and significantly different from zero (p<0.05 suggesting a scaling of trophic level with fish size. Both the list of trophic levels and the regression model should be of help in the formulation of trophic indicators and models of neotropical ecosystems. Rev. Biol. Trop. 59 (3: 1195-1203. Epub 2011 September 01.

  10. Space-time modelling of the spread of salmon lice between and within Norwegian marine salmon farms.

    Directory of Open Access Journals (Sweden)

    Magne Aldrin

    Full Text Available Parasitic salmon lice are potentially harmful to salmonid hosts and farm produced lice pose a threat to wild salmonids. To control salmon lice infections in Norwegian salmonid farming, numbers of lice are regularly counted and lice abundance is reported from all salmonid farms every month. We have developed a stochastic space-time model where monthly lice abundance is modelled simultaneously for all farms. The set of farms is regarded as a network where the degree of contact between farms depends on their seaway distance. The expected lice abundance at each farm is modelled as a function of i lice abundance in previous months at the same farm, ii at neighbourhood farms, and iii other, unspecified sources. In addition, the model includes explanatory variables such as seawater temperature and farm-numbers of fish. The model gives insight into factors that affect salmon lice abundance and contributing sources of infection. New findings in this study were that 66% of the expected salmon lice abundance was attributed to infection within farms, 28% was attributed to infection from neighbourhood farms and 6% to non-specified sources of infection. Furthermore, we present the relative risk of infection between neighbourhood farms as a function of seaway distance, which can be viewed as a between farm transmission kernel for salmon lice. The present modelling framework lays the foundation for development of future scenario simulation tools for examining the spread and abundance of salmon lice on farmed salmonids under different control regimes.

  11. Ectoparasite Caligus rogercresseyi modifies the lactate response in Atlantic salmon (Salmo salar) and Coho salmon (Oncorhynchus kisutch).

    Science.gov (United States)

    Vargas-Chacoff, L; Muñoz, J L P; Hawes, C; Oyarzún, R; Pontigo, J P; Saravia, J; González, M P; Mardones, O; Labbé, B S; Morera, F J; Bertrán, C; Pino, J; Wadsworth, S; Yáñez, A

    2017-08-30

    Although Caligus rogercresseyi negatively impacts Chilean salmon farming, the metabolic effects of infection by this sea louse have never been completely characterized. Therefore, this study analyzed lactate responses in the plasma, as well as the liver/muscle lactate dehydrogenase (LDH) activity and gene expression, in Salmo salar and Oncorhynchus kisutch infested by C. rogercresseyi. The lactate responses of Atlantic and Coho salmon were modified by the ectoparasite. Both salmon species showed increasing in plasma levels, whereas enzymatic activity increased in the muscle but decreased in the liver. Gene expression was overexpressed in both Coho salmon tissues but only in the liver for Atlantic salmon. These results suggest that salmonids need more energy to adapt to infection, resulting in increased gene expression, plasma levels, and enzyme activity in the muscles. The responses differed between both salmon species and over the course of infection, suggesting potential species-specific responses to sea-lice infection. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Persistent forecasting of disruptive technologies

    National Research Council Canada - National Science Library

    Committee on Forecasting Future Disruptive Technologies; National Research Council

    ...) and the Defense Intelligence Agency (DIA) tasked the Committee for Forecasting Future Disruptive Technologies with providing guidance and insight on how to build a persistent forecasting system to predict, analyze, and reduce the impact...

  13. Vortex disruption by magnetohydrodynamic feedback

    CERN Document Server

    Mak, Julian; Hughes, D W

    2016-01-01

    In an electrically conducting fluid, vortices stretch out a weak, large-scale magnetic field to form strong current sheets on their edges. Associated with these current sheets are magnetic stresses, which are subsequently released through reconnection, leading to vortex disruption, and possibly even destruction. This disruption phenomenon is investigated here in the context of two-dimensional, homogeneous, incompressible magnetohydrodynamics. We derive a simple order of magnitude estimate for the magnetic stresses --- and thus the degree of disruption --- that depends on the strength of the background magnetic field (measured by the parameter $M$, a ratio between the Alfv\\'en speed and a typical flow speed) and on the magnetic diffusivity (measured by the magnetic Reynolds number $\\mbox{Rm}$). The resulting estimate suggests that significant disruption occurs when $M^{2}\\mbox{Rm} = O(1)$. To test our prediction, we analyse direct numerical simulations of vortices generated by the breakup of unstable shear flo...

  14. Ultrasonic disruption of algae cells

    Science.gov (United States)

    King, P. M.; Nowotarski, K.; Joyce, E. M.; Mason, T. J.

    2012-05-01

    During last decade there has been increasing interest in the production of sustainable fuels from microalgae (R.H. Wijffels and M.J. Barbosa, 2010; Singh et al 2011; D.H. Lee 2011). The aim of this project was to determine if algal cells can be ultrasonically disrupted to release lipids for biofuel production. Ultrasonic disruption of two unicellular algal species: Dunnaliella salina and Nannochloropsis oculata was investigated using a 20 kHz probe. Haemocytometer, optical density, UV-Vis, fluoro-spectrophotometer and confocal microscopy results demonstrated complete cell destruction of Dunaliella salina within 16 minutes of sonication. Results obtained for Nannochloropsis oculata differed in that ultrasound dispersed clumped cells with little or no cell disruption, as observed by haemocytometer and confocal microscopy analysis. However, UV-Visible and fluoro-spectrophotometer analysis indicated chlorophyll release following sonication, suggesting some cell disruption had occurred.

  15. Contamination of salmon fillets and processing plants with spoilage bacteria.

    Science.gov (United States)

    Møretrø, Trond; Moen, Birgitte; Heir, Even; Hansen, Anlaug Å; Langsrud, Solveig

    2016-11-21

    The processing environment of salmon processing plants represents a potential major source of bacteria causing spoilage of fresh salmon. In this study, we have identified major contamination routes of important spoilage associated species within the genera Pseudomonas, Shewanella and Photobacterium in pre-rigor processing of salmon. Bacterial counts and culture-independent 16S rRNA gene analysis on salmon fillet from seven processing plants showed higher levels of Pseudomonas spp. and Shewanella spp. in industrially processed fillets compared to salmon processed under strict hygienic conditions. Higher levels of Pseudomonas spp. and Shewanella spp. were found on fillets produced early on the production day compared to later processed fillets. The levels of Photobacterium spp. were not dependent on the processing method or time of processing. In follow-up studies of two plants, bacterial isolates (n=2101) from the in-plant processing environments (sanitized equipment/machines and seawater) and from salmon collected at different sites in the production were identified by partial 16S rRNA gene sequencing. Pseudomonas spp. dominated in equipment/machines after sanitation with 72 and 91% of samples from the two plants being Pseudomonas-positive. The phylogenetic analyses, based on partial 16S rRNA gene sequencing, showed 48 unique sequence profiles of Pseudomonas of which two were dominant. Only six profiles were found on both machines and in fillets in both plants. Shewanella spp. were found on machines after sanitation in the slaughter department while Photobacterium spp. were not detected after sanitation in any parts of the plants. Shewanella spp. and Photobacterium spp. were found on salmon in the slaughter departments. Shewanella was frequently present in seawater tanks used for bleeding/short term storage. In conclusion, this study provides new knowledge on the processing environment as a source of contamination of salmon fillets with Pseudomonas spp. and

  16. AFSC/ABL: Genetic Analysis of Immature Bering Sea Chum Salmon: Part I. Baseline Evaluation

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Chum salmon populations from across their geographic distribution have been analyzed with a set of SNP and microsatellite markers. As is typical for chum salmon...

  17. Assessing sufficiency of thermal riverscapes for resilient salmon and steelhead populations

    Science.gov (United States)

    Resilient salmon populations require river networks that provide water temperature regimes sufficient to support a diversity of salmonid life histories across space and time. Efforts to protect, enhance and restore watershed thermal regimes for salmon may target specific location...

  18. Notes on the flora and fauna of the Dog Salmon River

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — During the summer of 1983, the Fishery Resources of the Dog Salmon River were investigated by members of the King Salmon Fishery Resources Station (U.S. Fish and...

  19. AFSC/ABL: Chum salmon bycatch genetic stock identification 1994-1995 Bering Sea

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In some years, the Bering Sea trawl fishery incidentally harvests (bycatch) large numbers of chum salmon. Because chum salmon were declining in some western Alaska...

  20. 77 FR 58526 - Pacific Fishery Management Council; Public Meeting; Work Session To Review Proposed Salmon...

    Science.gov (United States)

    2012-09-21

    ... public meeting. SUMMARY: The Pacific Fishery Management Council's Salmon Technical Team (STT), Scientific... FURTHER INFORMATION CONTACT: Mr. Mike Burner, Salmon Management Staff Officer, Pacific Fishery Management... National Oceanic and Atmospheric Administration RIN 0648-XC233 Pacific Fishery Management Council; Public...

  1. Fisheries impacts on lake ecosystem structure in the context of a changing climate and trophic state

    OpenAIRE

    Noges, Tiina; Anneville, Orlane; Guillard, Jean; Haberman, Juta; Jarvalt, Ain; Manca, Marina; Morabito, Giuseppe; Rogora, Michela; Thackeray, Stephen J.; Volta, Pietro; Winfield, Ian J.; NOGES Peeter

    2017-01-01

    Through cascading effects within lake food webs, commercial and recreational fisheries may indirectly affect the abundances of organisms at lower trophic levels, such as phytoplankton, even if they are not directly consumed. So far, interactive effects of fisheries, changing trophic state and climate upon lake ecosystems have been largely overlooked. Here we analyse case studies from five European lake basins of differing trophic states (Lake Võrtsjärv, two basins of Windermere, Lake Geneva a...

  2. Analysis of trophic structure of two carnivore assemblages by means of guild identification

    OpenAIRE

    Zapata, Sonia C.; Travaini, Alejandro; Ferreras, Pablo; Delibes, M.

    2007-01-01

    We evaluated the existence of trophic guild struc- ture, considering seasonal and annual variation, in two terrestrial carnivore assemblages: one from Santa Cruz province (Argentinean Patagonia, composed by six carni- vore species), and the other from Doñana National Park (SW Spain, composed by five carnivore species). To identify trophic guilds, we first studied seasonal and annual diets of predators, calculated trophic overlap among species pairs, and then constructed overlap matrices (...

  3. Nonlinear disruption of ecological interactions in response to nitrogen deposition.

    Science.gov (United States)

    Ochoa-Hueso, Raúl

    2016-10-01

    Global environmental change (GEC) is affecting species interactions and causing a rapid decline in biodiversity. In this study, I present a new Ecosystem Disruption Index to quantify the impacts of simulated nitrogen (N) deposition (0, 10, 20, and 50 kg N·ha(-1) ·yr(-1)  + 6-7 kg N·ha(-1) ·yr(-1) background) on abiotic and biotic ecological interactions. This comparative index is based on pairwise linear and quadratic regression matrices. These matrices, calculated at the N treatment level, were constructed using a range of abiotic and biotic ecosystem constituents: soil pH, shrub cover, and the first component of several separate principal component analyses using soil fertility data (total carbon and N) and community data (annual plants, microorganisms, biocrusts, edaphic fauna) for a total of seven ecosystem constituents. Four years of N fertilization in a semiarid shrubland completely disrupted the network of ecological interactions, with a greater proportional increase in ecosystem disruption at low N addition levels. Biotic interactions, particularly those involving microbes, shrubs, and edaphic fauna, were more prone to be lost in response to N, whereas interactions involving soil properties were more resilient. In contrast, edaphic fauna was the only group directly affected by N addition, with mites and collembolans increasing their abundance with up to 20 kg N·ha(-1) ·yr(-1) and then decreasing, which supports the idea of higher-trophic-level organisms being more sensitive to disturbance due to more complex links with other ecosystem constituents. Future experimental studies evaluating the impacts of N deposition, and possibly other GEC drivers, on biodiversity and biotic and abiotic interactions may be able to explain results more effectively in the context of ecological networks as a key feature of ecosystem sensitivity. © 2016 by the Ecological Society of America.

  4. Overfishing and nutrient pollution interact with temperature to disrupt coral reefs down to microbial scales.

    Science.gov (United States)

    Zaneveld, Jesse R; Burkepile, Deron E; Shantz, Andrew A; Pritchard, Catharine E; McMinds, Ryan; Payet, Jérôme P; Welsh, Rory; Correa, Adrienne M S; Lemoine, Nathan P; Rosales, Stephanie; Fuchs, Corinne; Maynard, Jeffrey A; Thurber, Rebecca Vega

    2016-06-07

    Losses of corals worldwide emphasize the need to understand what drives reef decline. Stressors such as overfishing and nutrient pollution may reduce resilience of coral reefs by increasing coral-algal competition and reducing coral recruitment, growth and survivorship. Such effects may themselves develop via several mechanisms, including disruption of coral microbiomes. Here we report the results of a 3-year field experiment simulating overfishing and nutrient pollution. These stressors increase turf and macroalgal cover, destabilizing microbiomes, elevating putative pathogen loads, increasing disease more than twofold and increasing mortality up to eightfold. Above-average temperatures exacerbate these effects, further disrupting microbiomes of unhealthy corals and concentrating 80% of mortality in the warmest seasons. Surprisingly, nutrients also increase bacterial opportunism and mortality in corals bitten by parrotfish, turning normal trophic interactions deadly for corals. Thus, overfishing and nutrient pollution impact reefs down to microbial scales, killing corals by sensitizing them to predation, above-average temperatures and bacterial opportunism.

  5. Rotifer trophic state indices as ecosystem indicators in brackish coastal waters

    Directory of Open Access Journals (Sweden)

    Agnieszka Gutkowska

    2013-11-01

    Full Text Available Thanks to their short life cycles, rotifers react rapidly to changes in environmental conditions and so may be useful for biological monitoring. The objective of this paper was to investigate the applicability of rotifer trophic state indices as indicators of the trophic state of brackish waters, as exemplified by the Vistula Lagoon. Carried out in summer from 2007 to 2011, this study showed no significant correlation between the Lagoon's trophic state and the rotifer structure. This confirms the limited applicability of rotifer trophic state indices for evaluating water quality in brackish water bodies.

  6. Fungal community homogenization, shift in dominant trophic guild, and appearance of novel taxa with biotic invasion

    National Research Council Canada - National Science Library

    Anthony, M. A; Frey, S. D; Stinson, K. A

    2017-01-01

    .... Here, we compared fungal biomass, diversity, community composition, and the relative abundance of fungal trophic guilds, along with edaphic properties of soils collected from uninvaded and invaded...

  7. Os grupos tróficos em Coleoptera The trophic groups in Coleoptera

    Directory of Open Access Journals (Sweden)

    Renato C. Marinoni

    2001-03-01

    Full Text Available The beetles are a useful group for studies on trophic structure of communities, mainly in forested areas. These kind of studies are based on food habits of species groups. The different terms applied to nomminated these groups (trophic category, ecologic group, trophic group, guild, trophic guild are discussed. The term trophic group, a natural unity, is proposed to form a group of species with the same food habits, not considering the trophic level. The guild, an artificial unity, is recognized as an important tool to group organisms group that use the same resources as defined by the investigator (Hawkins & MacMaiion, 1989; Simberloff & Dayan 1991; Wilson 1999. The known alimentary habits of Coleoptera are classified in five trophic groups - herbivores, algivores, fungívores, detrivores and carnivores. Within each trophic group, subgroups are recognized. The subgroup are in a lower hierarchic level and are defined by morphological (herbivores, taxonomic (fungivores atributes of the food, by the food origin (detrivores and by the way that the food is obtained (carnivores. A food resource diagram showing connections among the trophic groups, based on consumer-consumed (predator-prey relations, is presented.

  8. Effect of salting process on the histological structure of salmon flesh

    OpenAIRE

    Astruc, Thierry; Loison, Olivier; Venien, Annie; Jiang, Weijunlang; Gaubain, Oulyana

    2017-01-01

    Atlantic Salmon , Salmo Salar, is composed of approximately 70% water, 19% protein, 10% lipid and 1% small nutrients (vitamins, glycogen, pigments ...). Smoked salmon comes from the processing of fresh salmon: the fillets are removed from the fish, salted and then smoked. Salting can be carried out with dry salt or by brine injection. The objective of the study was to compare the evolution of the cell structure and ultrastructure of the salmon muscle subjected to salting with dry salt and sal...

  9. Effects of salmon lice Lepeophtheirus salmonis onwild sea trout Salmo trutta—a literature review

    OpenAIRE

    Thorstad, Eva Bonsak; Todd, Christopher D.; Uglem, Ingebrigt; Bjørn, Pål Arne; Gargan, Patrick G.; Vollset, Knut Wiik; Halttunen, Elina; Kålås, Steinar; Berg, Marius; Finstad, Bengt

    2015-01-01

    - Salmon farming increases the abundance of salmon lice, which are ectoparasites of salmonids in the sea. Here we review the current knowledge on the effects of salmon lice on wild sea trout. Salmon lice feed on host mucus, skin and muscle, and infestation may induce osmoregulatory dysfunction, physiological stress, anaemia, reduced feeding and growth, increased susceptibility to secondary infections, reduced disease resistance and ultimately mortality of individual sea trou...

  10. Effects of salmon lice Lepeophtheirus salmonis onwild sea trout Salmo trutta—a literature review

    OpenAIRE

    Thorstad, Eva Bonsak; Todd, Christopher D.; Uglem, Ingebrigt; Bjørn, Pål Arne; Gargan, Patrick G.; Vollset, Knut Wiik; Halttunen, Elina; Kålås, Steinar; Berg, Marius; Finstad, Bengt

    2015-01-01

    Salmon farming increases the abundance of salmon lice, which are ectoparasites of salmonids in the sea. Here we review the current knowledge on the effects of salmon lice on wild sea trout. Salmon lice feed on host mucus, skin and muscle, and infestation may induce osmoregulatory dysfunction, physiological stress, anaemia, reduced feeding and growth, increased susceptibility to secondary infections, reduced disease resistance and ultimately mortality of individual sea trout. Wi...

  11. Effects of salmon lice Lepeophtheirus salmonis on wild sea trout Salmo trutta—a literature review

    OpenAIRE

    Thorstad, Eva Bonsak; Todd, Christopher D.; Uglem, Ingebrigt; Bjørn, Pål Arne; Gargan, Patrick G.; Vollset, Knut Wiik; Halttunen, Elina; Kålås, Steinar; Berg, Marius; Finstad, Bengt

    2015-01-01

    Salmon farming increases the abundance of salmon lice, which are ectoparasites of salmonids in the sea. Here we review the current knowledge on the effects of salmon lice on wild sea trout. Salmon lice feed on host mucus, skin and muscle, and infestation may induce osmoregulatory dysfunction, physiological stress, anaemia, reduced feeding and growth, increased susceptibility to secondary infections, reduced disease resistance and ultimately mortality of individual sea trout. Wi...

  12. Deformity Prevalence and Meristic Characteristics in Atlantic salmon : The Effect of Ploidy, Incubation Temperature and Hybridization

    OpenAIRE

    Fleming, Mitchell

    2013-01-01

    Intense salmon farming regimes in Norway have resulted in hundreds of thousands of salmon escaping each year. These domesticated salmon have been selectively bred for generations and therefore have the potential to genetically infiltrate wild population’s causing gene flow, out breeding depression and ultimately a decline in stocks. Triploidization has become a popular method for inducing sterility into large batches of salmon. This study investigated the effects of triploidization on Atlanti...

  13. Salmon redd identification using environmental DNA (eDNA)

    Science.gov (United States)

    Pilliod, David S.; Laramie, Matthew B.

    2016-06-10

    IntroductionThe purpose of this project was to develop a technique to use environmental DNA (eDNA) to distinguish between redds made by Chinook salmon (Oncorhynchus tshawytscha) and redds made by Coho salmon (O. kisutch) and to distinguish utilized redds from test/abandoned redds or scours that have the appearance of redds. The project had two phases:Phase 1. Develop, test, and optimize a molecular assay for detecting and identifying Coho salmon DNA and differentiating it from Chinook salmon DNA.Phase 2. Demonstrate the efficacy of the technique.Collect and preserve water samples from the interstitial spaces of 10 known redds (as identified by expert observers) of each species and 10 gravel patches that do not include a redd of either species.Collect control samples from the water column adjacent to each redd to establish background eDNA levels.Analyze the samples using the developed molecular assays for Coho salmon (phase I) and Chinook salmon (Laramie and others, 2015).Evaluate whether samples collected from Chinook and Coho redds have significantly higher levels of eDNA of the respective species than background levels (that is, from gravel, water column).Evaluate whether samples collected from the interstitial spaces of gravel patches that are not redds are similar to background eDNA levels.The Sandy River is a large tributary of the Columbia River. The Sandy River meets the Columbia River approximately 23 km upstream of Portland, Oregon. The Sandy River Basin provides overlapping spawning habitat for both Chinook and Coho salmon.Samples provided by Portland Water Bureau for analysis were collected from the Bull Run River, Sixes Creek, Still Creek, Arrah Wanna Side Channel, and Side Channel 18.

  14. Variability of Lekanesphaera monodi metabolic rates with habitat trophic status

    Science.gov (United States)

    Vignes, Fabio; Fedele, Marialaura; Pinna, Maurizio; Mancinelli, Giorgio; Basset, Alberto

    2012-05-01

    Regulation of metabolism is a common strategy used by individuals to respond to a changing environment. The mechanisms underlying the variability of metabolic rates in macroinvertebrates are of primary importance in studying benthic-pelagic energy transfer in transitional water ecosystems. Lekanesphaera monodi is an isopod endemic to transitional water ecosystems that can modify its metabolic rate in response to environmental changes. Therefore it is a useful model in studying the influence of environmental factors on metabolism. This study focused on the interpopulation variability of standard metabolic rates (SMR) in L. monodi populations sampled in three transitional water ecosystems differing in their trophic status. The standard metabolic rates of L. monodi individuals across the same range of body size spectra were inferred from oxygen consumption measurements in a flow-through respirometer in the three populations and a body condition index was assessed for each population. Habitat trophic status was evaluated by monthly measurement of the basic physical-chemical parameters of the water column in the ecosystems for one year. Standard metabolic rates showed high variability, ranging from 0.27 to 10.14 J d-1. Body size accounted for more than 38% of total variability. In terms of trophic status, individuals from the eutrophic ecosystem had significantly higher standard metabolic rates than individuals from the other ecosystems (SMR = 2.3 J d-1 in Spunderati Sud vs. 1.36 J d-1 in Alimini and 0.69 J d-1 in Acquatina). The body conditions index was also higher in the population from the eutrophic ecosystem. Results show that standard metabolic rates and growth rates are directly related to habitat productivity in accordance with the expectations of the food habits hypothesis. A possible extension of this hypothesis to benthic invertebrates is proposed.

  15. Trophic Status Controls Mercury Methylation Pathways in Northern Peats

    Science.gov (United States)

    Hines, M. E.; Zhang, L.; Barkay, T.; Krabbenhoft, D. P.; Schaefer, J.; Hu, H.; Sidelinger, W.; Liu, X.; Wang, Y.

    2015-12-01

    Methyl mercury (MeHg) can be produced by a variety of microbes including syntrophs, methanogens, acetogens, and fermenters, besides sulfate (SO42-, SRB) and iron- reducing bacteria. Many freshwater wetlands are deficient in electron acceptors that support the traditional respiratory pathways of methylation, yet they accumulate high levels of MeHg. To investigate methylation in these wetlands and to connect these pathways with vegetation and microbial communities, incubation experiments were conducted using peats from 26 sites in Alaska. The sites were clustered using multiple factor analysis based on pH, temp, CH4 and volatile fatty acids production rates, and surface vegetation composition. Three clusters were generated and corresponded to three trophic levels that were manifested by three pH levels (3.5, 4.5, and 5). Hg methylation activity in laboratory incubations was determined using the short-lived radioisotope 197Hg. In the low pH, Sphagnum-dominated cluster, methylation rates were less than 1% day-1 and likely conducted by primary fermenters. Conversely, the high pH trophic cluster dominated by Carex aquatilis and active syntrophy exhibited Hg methylation rates as high as 12% day-1. In intermediate sites, rich in Sphagnum magellanicum with less Carex, a gradient in syntrophy and Hg methylation paths was observed. Amendments with process-stimulators and inhibitors revealed no evidence of SO42- reduction, but suggested that SRB, metabolizing either syntrophically with methanogens and/or by fermentation, likely methylated Hg. While on going metatranscriptomics studies are required to verify the role of syntrophs, fermenters, and methanogens as methylators, these results revealed that Hg methylation pathways change greatly along trophic gradients with a dominance of respiratory pathways in mineral-rich sites, syntrophy dominance in intermediate sites, and fermentation dominance in nutrient-poor sites.

  16. Diet and trophic niche of Lithobates catesbeianus (Amphibia: Anura

    Directory of Open Access Journals (Sweden)

    Peterson T. Leivas

    2012-10-01

    Full Text Available Lithobates catesbeianus (Shaw, 1802 is an invasive anuran introduced in Brazil that is associated with the displacement and the decline of populations of native species worldwide. There is evidence that biological invasions are facilitated by certain attributes of the invading species, for instance niche breath, and that invasive species have a broader ecological niche with respect to native ones. We designed a study to ascertain the temporal, ontogenetic, and sex differences in the niche dynamics of the American bullfrog. We sampled monthly from June 2008 to May 2009 in the state of Paraná, southern Brazil. For each individual, we gathered biometric and stomach content data. We then estimated the niche breath of the juveniles and adults, and compared it between the sexes. A total of 104 females and 77 males were sampled. Lithobates catesbeianus has a generalist diet, preying upon invertebrates and vertebrates. Even though the diet of the studied population varied seasonally, it did not differ between the sexes nor did it respond to biometric variables. Niche breadth was more restricted in the winter than in the autumn. The trophic niche of juveniles and adults did not overlap much when compared with the trophic niche overlap between males and females. Adult males and females had a considerable niche overlap, but females had a broader trophic niche than males in the winter and in the spring. These niche characteristics point to an opportunistic predation strategy that may have facilitated the process of invasion and establishment of this species in the study area.

  17. Comparative trophic morphology in eight species of damselfishes (Pomacentridae).

    Science.gov (United States)

    Frédérich, Bruno; Pilet, Arnaud; Parmentier, Eric; Vandewalle, Pierre

    2008-02-01

    Damselfishes show significant biodiversity in the coral reefs. To better understand such diversity, an ecomorphological approach was investigated in the trophic morphology of eight species of Pomacentridae (Chromis acares, C. margaritifer, Dascyllus aruanus, D. flavicaudus, Pomacentrus pavo, Plectroglyphidodon johnstonianus, Pl. lacrymatus and Stegastes nigricans) belonging to different trophic guilds (zooplankton, algal, coral polyp feeders and omnivores). Geometric morphometrics were used to quantify size and shape variations in four skeletal units: (1) neurocranium, (2) suspensorium and opercle, (3) mandible and (4) premaxilla. This method allowed us to reveal shape and size differences correlated to functional diversity both within and between trophic guilds. Among zooplanktivores, C. margaritifer, D. aruanus and D. flavicaudus have a high and long supraoccipital crest, short mandibles forming a small mouth and high suspensoria and opercles. These three species can be considered to be suction feeders. In the same guild, C. acares shows opposite characteristics (long and thin mandibles, lengthened neurocranium and suspensorium) and can be considered as a ram feeder. Among herbivores and corallivores, the two species of Plectroglyphidodon and S. nigricans can be considered as grazers. Differences in skeletal shape are mainly related to improving the robustness of some skeletal parts (broad hyomandibular, short and high mandibles). The shapes of P. pavo, which feeds largely on algae, strongly differ from that of the other three grazers exhibiting similar morphological characteristics to C. acares (e.g., long and shallow suspensorium, lengthened neurocranium). This highlights likely differences concerning cutting or scraping method. Finally, no strong correlations exist between size and shapes in the eight studied species. Size difference among species having a very similar shape could be viewed as a factor optimizing resource partitioning. Copyright (c) 2007 Wiley

  18. 76 FR 54216 - Pacific Fishery Management Council (Council); Work Session To Review Proposed Salmon Methodology...

    Science.gov (United States)

    2011-08-31

    ...); Work Session To Review Proposed Salmon Methodology Changes AGENCY: National Marine Fisheries Service... meeting. SUMMARY: The Pacific Fishery Management Council's Salmon Technical Team (STT), Scientific and... salmon methodology and conservation objective changes in a joint work session, which is open to the...

  19. Norwegian Salmon Goes to Market: The Case of the Austevoll Seafood Cluster

    Science.gov (United States)

    Phyne, John; Hovgaard, Gestur; Hansen, Gard

    2006-01-01

    This paper examines the impact of the globalisation of the farmed salmon commodity chain upon farmed salmon production in the western Norwegian municipality of Austevoll. On the basis of field research conducted in 2002 and 2003, we conclude that salmon farming in Austevoll has responded to the challenges of "buyer-driven" food chains by…

  20. 78 FR 34093 - An Assessment of Potential Mining Impacts on Salmon Ecosystems of Bristol Bay, Alaska

    Science.gov (United States)

    2013-06-06

    ... AGENCY An Assessment of Potential Mining Impacts on Salmon Ecosystems of Bristol Bay, Alaska AGENCY... the revised draft document titled, ``An Assessment of Potential Mining Impacts on Salmon Ecosystems of... Mining Impacts on Salmon Ecosystems of Bristol Bay, Alaska'' is available primarily via the Internet on...

  1. 77 FR 31353 - An Assessment of Potential Mining Impacts on Salmon Ecosystems of Bristol Bay, AK

    Science.gov (United States)

    2012-05-25

    ... AGENCY An Assessment of Potential Mining Impacts on Salmon Ecosystems of Bristol Bay, AK AGENCY... of Potential Mining Impacts on Salmon Ecosystems of Bristol Bay, Alaska'' (EPA-910-R-12-004a-d). The... draft ``An Assessment of Potential Mining Impacts on Salmon Ecosystems of Bristol Bay, Alaska'' is...

  2. The Lummi Indians and the Canadian/American Pacific Salmon Treaty.

    Science.gov (United States)

    Boxberger, Daniel L.

    1988-01-01

    Explores the probable impact of the 1985 international Pacific Salmon Treaty on the Lummi tribe's catch of Fraser River salmon and economic well-being. Discusses the 1974 Boldt Decision, which allocated half of Washington State's salmon catch to treaty tribes, and contradictions in the federal government's conception of international treaties. (SV)

  3. 77 FR 21716 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Salmon

    Science.gov (United States)

    2012-04-11

    ... Peninsula. The FMP delegates management of the sport fishery to the State in both areas. Although the FMP... FMP and would reaffirm that management of the commercial and sport salmon fisheries in the East Area... commercial and sport salmon fishing in the East Area. Revise the definition of Salmon Management Area, at Sec...

  4. On-farm evaluation of the Salmon Welfare Index Model (SWIM 1.0)

    NARCIS (Netherlands)

    Folkedal, O.; Pettersen, J.M.; Bracke, M.B.; Stien, L.H.; Nilsson, J.; Martins, C.; Breck, O.; Midtlyng, P.J.; Kristiansen, T.

    2016-01-01

    The present study investigated the operational feasibility of the recently developed Salmon Welfare Index Model (SWIM 1.0) designed for Atlantic salmon (Salmo salar L) in production cages. Ten salmon farms containing spring smolts were visited twice, first between May and June the first year in

  5. 76 FR 8345 - Endangered and Threatened Species; Recovery Plan Module for Columbia River Estuary Salmon and...

    Science.gov (United States)

    2011-02-14

    ...) are listed as threatened or endangered under the ESA: Snake River Sockeye salmon, Snake River spring/summer Chinook salmon, Snake River fall Chinook salmon, Snake River steelhead, Upper Columbia River... Water Resources Education Center, 6:30-8:30 p.m. We received nine comment letters by mail, fax, or e...

  6. TROPHIC RELATIONS OF LADY BEETLES (COLEOPTERA, COCCINELLIDAE OF THE URALS

    Directory of Open Access Journals (Sweden)

    Z. I. Tyumaseva

    2016-05-01

    Full Text Available The article contains the study of the trophic relations of the lady beetles living in the Urals. The study allocates three ecological groups depending on the peculiarities of the beetles and larvae nutrition: phytophages, micetophages, and entomophages-predators. We have revealed 66 species of lady birds-predators and two species-phytophages: Subcoccinella vigintiquatuorpunctata (Linnaeus, 1758 and Bulaea lichatschovii (Hummel, 1827. In the group of obligatory micetophages in the Urals we registered the representatives of the tribe Halyziini, it is Halyzia sedecimguttata (Linnaeus, 1758 and Psyllobora vigintiduopunctata (Linnaeus, 1758.

  7. Captive Rearing Program for Salmon River Chinook Salmon, 2000 Project Progress Report.

    Energy Technology Data Exchange (ETDEWEB)

    Venditti, David A.

    2002-04-01

    During 2000, the Idaho Department of Fish and Game (IDFG) continued to develop techniques to rear chinook salmon Oncorhynchus tshawytscha to sexual maturity in captivity and to monitor their reproductive performance under natural conditions. Eyed-eggs were collected to establish captive cohorts from three study streams and included 503 eyed-eggs from East Fork Salmon River (EFSR), 250 from the Yankee Fork Salmon River, and 304 from the West Fork Yankee Fork Salmon River (WFYF). After collection, the eyed-eggs were immediately transferred to the Eagle Fish Hatchery, where they were incubated and reared by family group. Juveniles collected the previous summer were PIT and elastomer tagged and vaccinated against vibrio Vibrio spp. and bacterial kidney disease before the majority (approximately 75%) were transferred to the National Marine Fisheries Service, Manchester Marine Experimental Station for saltwater rearing through sexual maturity. Smolt transfers included 158 individuals from the Lemhi River (LEM), 193 from the WFYF, and 372 from the EFSR. Maturing fish transfers from the Manchester facility to the Eagle Fish Hatchery included 77 individuals from the LEM, 45 from the WFYF, and 11 from the EFSR. Two mature females from the WFYF were spawned in captivity with four males in 2000. Only one of the females produced viable eggs (N = 1,266), which were placed in in-stream incubators by personnel from the Shoshone-Bannock Tribe. Mature adults (N = 70) from the Lemhi River were released into Big Springs Creek to evaluate their reproductive performance. After release, fish distributed themselves throughout the study section and displayed a progression of habitat associations and behavior consistent with progressing maturation and the onset of spawning. Fifteen of the 17 suspected redds spawned by captive-reared parents in Big Springs Creek were hydraulically sampled to assess survival to the eyed stage of development. Eyed-eggs were collected from 13 of these, and

  8. Molecular pathology of vertebral deformities in hyperthermic Atlantic salmon (Salmo salar

    Directory of Open Access Journals (Sweden)

    Hjelde Kirsti

    2010-07-01

    Full Text Available Abstract Background Hyperthermia has been shown in a number of organisms to induce developmental defects as a result of changes in cell proliferation, differentiation and gene expression. In spite of this, salmon aquaculture commonly uses high water temperature to speed up developmental rate in intensive production systems, resulting in an increased frequency of skeletal deformities. In order to study the molecular pathology of vertebral deformities, Atlantic salmon was subjected to hyperthermic conditions from fertilization until after the juvenile stage. Results Fish exposed to the high temperature regime showed a markedly higher growth rate and a significant higher percentage of deformities in the spinal column than fish reared at low temperatures. By analyzing phenotypically normal spinal columns from the two temperature regimes, we found that the increased risk of developing vertebral deformities was linked to an altered gene transcription. In particular, down-regulation of extracellular matrix (ECM genes such as col1a1, osteocalcin, osteonectin and decorin, indicated that maturation and mineralization of osteoblasts were restrained. Moreover, histological staining and in situ hybridization visualized areas with distorted chondrocytes and an increased population of hypertrophic cells. These findings were further confirmed by an up-regulation of mef2c and col10a, genes involved in chondrocyte hypertrophy. Conclusion The presented data strongly indicates that temperature induced fast growth is severely affecting gene transcription in osteoblasts and chondrocytes; hence change in the vertebral tissue structure and composition. A disrupted bone and cartilage production was detected, which most likely is involved in the higher rate of deformities developed in the high intensive group. Our results are of basic interest for bone metabolism and contribute to the understanding of the mechanisms involved in development of temperature induced

  9. Science for a wilder Anthropocene: Synthesis and future directions for trophic rewilding research.

    Science.gov (United States)

    Svenning, Jens-Christian; Pedersen, Pil B M; Donlan, C Josh; Ejrnæs, Rasmus; Faurby, Søren; Galetti, Mauro; Hansen, Dennis M; Sandel, Brody; Sandom, Christopher J; Terborgh, John W; Vera, Frans W M

    2016-01-26

    Trophic rewilding is an ecological restoration strategy that uses species introductions to restore top-down trophic interactions and associated trophic cascades to promote self-regulating biodiverse ecosystems. Given the importance of large animals in trophic cascades and their widespread losses and resulting trophic downgrading, it often focuses on restoring functional megafaunas. Trophic rewilding is increasingly being implemented for conservation, but remains controversial. Here, we provide a synthesis of its current scientific basis, highlighting trophic cascades as the key conceptual framework, discussing the main lessons learned from ongoing rewilding projects, systematically reviewing the current literature, and highlighting unintentional rewilding and spontaneous wildlife comebacks as underused sources of information. Together, these lines of evidence show that trophic cascades may be restored via species reintroductions and ecological replacements. It is clear, however, that megafauna effects may be affected by poorly understood trophic complexity effects and interactions with landscape settings, human activities, and other factors. Unfortunately, empirical research on trophic rewilding is still rare, fragmented, and geographically biased, with the literature dominated by essays and opinion pieces. We highlight the need for applied programs to include hypothesis testing and science-based monitoring, and outline priorities for future research, notably assessing the role of trophic complexity, interplay with landscape settings, land use, and climate change, as well as developing the global scope for rewilding and tools to optimize benefits and reduce human-wildlife conflicts. Finally, we recommend developing a decision framework for species selection, building on functional and phylogenetic information and with attention to the potential contribution from synthetic biology.

  10. Thermal adaptation and phenotypic plasticity in a warming world: Insights from common garden experiments on Alaskan sockeye salmon

    Science.gov (United States)

    Sparks, Morgan M.; Westley, Peter A. H.; Falke, Jeffrey A.; Quinn, Thomas P.

    2017-01-01

    An important unresolved question is how populations of coldwater-dependent fishes will respond to rapidly warming water temperatures. For example, the culturally and economically important group, Pacific salmon (Oncorhynchus spp.), experience site-specific thermal regimes during early development that could be disrupted by warming. To test for thermal local adaptation and heritable phenotypic plasticity in Pacific salmon embryos, we measured the developmental rate, survival, and body size at hatching in two populations of sockeye salmon (Oncorhynchus nerka) that overlap in timing of spawning but incubate in contrasting natural thermal regimes. Using a split half-sibling design, we exposed embryos of 10 families from each of two populations to variable and constant thermal regimes. These represented both experienced temperatures by each population, and predicted temperatures under plausible future conditions based on a warming scenario from the downscaled global climate model (MIROC A1B scenario). We did not find evidence of thermal local adaptation during the embryonic stage for developmental rate or survival. Within treatments, populations hatched within 1 day of each other, on average, and amongtreatments, did not differ in survival in response to temperature. We did detect plasticity to temperature; embryos developed 2.5 times longer (189 days) in the coolest regime compared to the warmest regime (74 days). We also detected variation in developmental rates among families within and among temperature regimes, indicating heritable plasticity. Families exhibited a strong positive relationship between thermal variability and phenotypic variability in developmental rate but body length and mass at hatching were largely insensitive to temperature. Overall, our results indicated a lack of thermal local adaptation, but a presence of plasticity in populations experiencing contrasting conditions, as well as family-specific heritable plasticity that could

  11. Wild Steelhead Studies, Salmon and Clearwater Rivers, 1994 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Holubetz, Terry B; Leth, Brian D.

    1997-05-01

    To enumerate chinook salmon Oncorhynchus tshawytscha and steelhead O. mykiss adult escapements, weirs were operated in Marsh, Chamberlain, West Fork Chamberlain, and Running creeks. Beginning in late July 1994, a juvenile trap was installed in Running Creek to estimate juvenile outmigrants. Plans have been completed to install a weir in Rush Creek to enumerate steelhead adult escapement beginning in spring 1995. Design and agreements are being developed for Johnson Creek and Captain John Creek. Data collected in 1993 and 1994 indicate that spring chinook salmon and group-B steelhead populations and truly nearing extinction levels. For example, no adult salmon or steelhead were passed above the West Fork Chamberlain Creek weir in 1984, and only 6 steelhead and 16 chinook salmon were passed into the important spawning area on upper Marsh Creek. Group-A steelhead are considerably below desirable production levels, but in much better status than group-B stocks. Production of both group-A and group-B steelhead is being limited by low spawning escapements. Studies have not been initiated on wild summer chinook salmon stocks.

  12. Quality grading of Atlantic salmon (Salmo salar) by computer vision.

    Science.gov (United States)

    Misimi, E; Erikson, U; Skavhaug, A

    2008-06-01

    In this study, we present a promising method of computer vision-based quality grading of whole Atlantic salmon (Salmo salar). Using computer vision, it was possible to differentiate among different quality grades of Atlantic salmon based on the external geometrical information contained in the fish images. Initially, before the image acquisition, the fish were subjectively graded and labeled into grading classes by a qualified human inspector in the processing plant. Prior to classification, the salmon images were segmented into binary images, and then feature extraction was performed on the geometrical parameters of the fish from the grading classes. The classification algorithm was a threshold-based classifier, which was designed using linear discriminant analysis. The performance of the classifier was tested by using the leave-one-out cross-validation method, and the classification results showed a good agreement between the classification done by human inspectors and by the computer vision. The computer vision-based method classified correctly 90% of the salmon from the data set as compared with the classification by human inspector. Overall, it was shown that computer vision can be used as a powerful tool to grade Atlantic salmon into quality grades in a fast and nondestructive manner by a relatively simple classifier algorithm. The low cost of implementation of today's advanced computer vision solutions makes this method feasible for industrial purposes in fish plants as it can replace manual labor, on which grading tasks still rely.

  13. Sexual difference in PCB concentrations of coho salmon (Oncorhynchus kisutch)

    Science.gov (United States)

    Madenjian, Charles P.; Schrank, Candy S.; Begnoche, Linda J.; Elliott, Robert F.; Quintal, Richard T.

    2010-01-01

    We determined polychlorinated biphenyl (PCB) concentrations in 35 female coho salmon (Oncorhynchus kisutch) and 60 male coho salmon caught in Lake Michigan (Michigan and Wisconsin, United States) during the fall of 1994 and 1995. In addition, we determined PCB concentrations in the skin-on fillets of 26 female and 19 male Lake Michigan coho salmon caught during the fall of 2004 and 2006. All coho salmon were age-2 fish. These fish were caught prior to spawning, and therefore release of eggs could not account for sexual differences in PCB concentrations because female coho salmon spawn only once during their lifetime. To investigate whether gross growth efficiency (GGE) differed between the sexes, we applied bioenergetics modeling. Results showed that, on average, males were 19% higher in PCB concentration than females, based on the 1994–1995 dataset. Similarly, males averaged a 20% higher PCB concentration in their skin-on fillets compared with females. According to the bioenergetics modeling results, GGE of adult females was less than 1% higher than adult male GGE. Thus, bioenergetics modeling could not explain the 20% higher PCB concentration exhibited by the males. Nonetheless, a sexual difference in GGE remained a plausible explanation for the sexual difference in PCB concentrations.

  14. Teachers' Emotional Expression about Disruptive Boys

    Science.gov (United States)

    Daley, D.; Renyard, L.; Sonuga-Barke, E. J. S.

    2005-01-01

    Objectives: To assess teachers' emotional expression about pupils using the Five Minute Speech Sample (FMSS) and coding procedures for parental expressed emotion (EE). To compare EE for disruptive and non-disruptive pupils. Method: Twenty-one teachers provided speech samples for both a disruptive and a non-disruptive pupil in their class selected…

  15. Online Education Cast as "Disruptive Innovation"

    Science.gov (United States)

    Totter, Andrew

    2008-01-01

    Technology-based forces of "disruptive innovation" are gathering around public education and will overhaul the way K-12 students learn--with potentially dramatic consequences for established public schools, according to an upcoming book that draws parallels to disruptions in other industries. In his "Disrupting Class: How Disruptive Innovation…

  16. Adaptive strategies and life history characteristics in a warming climate: salmon in the Arctic?

    Science.gov (United States)

    Nielsen, Jennifer L.; Ruggerone, Gregory T.; Zimmerman, Christian E.

    2013-01-01

    In the warming Arctic, aquatic habitats are in flux and salmon are exploring their options. Adult Pacific salmon, including sockeye (Oncorhynchus nerka), coho (O. kisutch), Chinook (O. tshawytscha), pink (O. gorbuscha) and chum (O. keta) have been captured throughout the Arctic. Pink and chum salmon are the most common species found in the Arctic today. These species are less dependent on freshwater habitats as juveniles and grow quickly in marine habitats. Putative spawning populations are rare in the North American Arctic and limited to pink salmon in drainages north of Point Hope, Alaska, chum salmon spawning rivers draining to the northwestern Beaufort Sea, and small populations of chum and pink salmon in Canada’s Mackenzie River. Pacific salmon have colonized several large river basins draining to the Kara, Laptev and East Siberian seas in the Russian Arctic. These populations probably developed from hatchery supplementation efforts in the 1960’s. Hundreds of populations of Arctic Atlantic salmon (Salmo salar) are found in Russia, Norway and Finland. Atlantic salmon have extended their range eastward as far as the Kara Sea in central Russian. A small native population of Atlantic salmon is found in Canada’s Ungava Bay. The northern tip of Quebec seems to be an Atlantic salmon migration barrier for other North American stocks. Compatibility between life history requirements and ecological conditions are prerequisite for salmon colonizing Arctic habitats. Broad-scale predictive models of climate change in the Arctic give little information about feedback processes contributing to local conditions, especially in freshwater systems. This paper reviews the recent history of salmon in the Arctic and explores various patterns of climate change that may influence range expansions and future sustainability of salmon in Arctic habitats. A summary of the research needs that will allow informed expectation of further Arctic colonization by salmon is given.

  17. Upstream trophic structure modulates downstream community dynamics via resource subsidies.

    Science.gov (United States)

    Harvey, Eric; Gounand, Isabelle; Little, Chelsea J; Fronhofer, Emanuel A; Altermatt, Florian

    2017-08-01

    In many natural systems, the physical structure of the landscape dictates the flow of resources. Despite mounting evidence that communities' dynamics can be indirectly coupled by reciprocal among ecosystem resource flows, our understanding of how directional resource flows might indirectly link biological communities is limited. We here propose that differences in community structure upstream should lead to different downstream dynamics, even in the absence of dispersal of organisms. We report an experimental test of the effect of upstream community structure on downstream community dynamics in a simplified but highly controlled setting, using protist microcosms. We implemented directional flows of resources, without dispersal, from a standard resource pool into upstream communities of contrasting interaction structure and then to further downstream communities of either one or two trophic levels. Our results demonstrate that different types of species interactions in upstream habitats may lead to different population sizes and levels of biomass in these upstream habitats. This, in turn, leads to varying levels of detritus transfer (dead biomass) to the downstream communities, thus influencing their population densities and trophic interactions in predictable ways. Our results suggest that the structure of species interactions in directionally structured ecosystems can be a key mediator of alterations to downstream habitats. Alterations to upstream habitats can thus cascade down to downstream communities, even without dispersal.

  18. EVALUATION OF THE WATER TROPHIC STATE OF WAPIENICA DAM RESERVOIR

    Directory of Open Access Journals (Sweden)

    Ewa Jachniak

    2015-01-01

    Full Text Available In this publication the trophy level of Wapienica dam reservoir, based on the composition species of planktonic algae and their biomass, and concentrations of chlorophyll a, was defined. The research was conducted during the vegetative season in 2013 year; the samples were taken from two research points (W1 – the part of river Wapienica inflow to reservoir and W2 – the part of the reservoir dam by using bathometer. The whole biomass of planktonic algae and concentration of chlorophyll a from two research areas were low and it allowed to classify water of this reservoir to oligo-/ mesotrophic. Only in the part of the reservoir dam, in summer season, an increased trophy level was observed (Heinonen 1980. A similar trophic character (oligo-/ mesotrophic of the water reservoir was also indicated by algae species: Achnanthes lanceolata (Bréb. Grun. in Cl. and Grun., Chrysoccoccus minutus (Fritsch Nygaard. For a temporary increase of the trophy level, the diatom Nitzschia acicularis (Kütz. W. Sm. could indicate, because it is a typical species in poorly eutrophic water. The green algae (Pediastrum and Coelastrum, which were observed in summer season could also indicate for a rise of the trophic state, because they are typical for eutrophic water.

  19. Bioenergetics, Trophic Ecology, and Niche Separation of Tunas.

    Science.gov (United States)

    Olson, R J; Young, J W; Ménard, F; Potier, M; Allain, V; Goñi, N; Logan, J M; Galván-Magaña, F

    Tunas are highly specialized predators that have evolved numerous adaptations for a lifestyle that requires large amounts of energy consumption. Here we review our understanding of the bioenergetics and feeding dynamics of tunas on a global scale, with an emphasis on yellowfin, bigeye, skipjack, albacore, and Atlantic bluefin tunas. Food consumption balances bioenergetics expenditures for respiration, growth (including gonad production), specific dynamic action, egestion, and excretion. Tunas feed across the micronekton and some large zooplankton. Some tunas appear to time their life history to take advantage of ephemeral aggregations of crustacean, fish, and molluscan prey. Ontogenetic and spatial diet differences are substantial, and significant interdecadal changes in prey composition have been observed. Diet shifts from larger to smaller prey taxa highlight ecosystem-wide changes in prey availability and diversity and provide implications for changing bioenergetics requirements into the future. Where tunas overlap, we show evidence of niche separation between them; resources are divided largely by differences in diet percentages and size ranges of prey taxa. The lack of long-term data limits the ability to predict impacts of climate change on tuna feeding behaviour. We note the need for systematic collection of feeding data as part of routine monitoring of these species, and we highlight the advantages of using biochemical techniques for broad-scale analyses of trophic relations. We support the continued development of ecosystem models, which all too often lack the regional-specific trophic data needed to adequately investigate climate and fishing impacts. © 2016 Elsevier Ltd. All rights reserved.

  20. Global change in the trophic functioning of marine food webs.

    Science.gov (United States)

    Maureaud, Aurore; Gascuel, Didier; Colléter, Mathieu; Palomares, Maria L D; Du Pontavice, Hubert; Pauly, Daniel; Cheung, William W L

    2017-01-01

    The development of fisheries in the oceans, and other human drivers such as climate warming, have led to changes in species abundance, assemblages, trophic interactions, and ultimately in the functioning of marine food webs. Here, using a trophodynamic approach and global databases of catches and life history traits of marine species, we tested the hypothesis that anthropogenic ecological impacts may have led to changes in the global parameters defining the transfers of biomass within the food web. First, we developed two indicators to assess such changes: the Time Cumulated Indicator (TCI) measuring the residence time of biomass within the food web, and the Efficiency Cumulated Indicator (ECI) quantifying the fraction of secondary production reaching the top of the trophic chain. Then, we assessed, at the large marine ecosystem scale, the worldwide change of these two indicators over the 1950-2010 time-periods. Global trends were identified and cluster analyses were used to characterize the variability of trends between ecosystems. Results showed that the most common pattern over the study period is a global decrease in TCI, while the ECI indicator tends to increase. Thus, changes in species assemblages would induce faster and apparently more efficient biomass transfers in marine food webs. Results also suggested that the main driver of change over that period had been the large increase in fishing pressure. The largest changes occurred in ecosystems where 'fishing down the marine food web' are most intensive.

  1. [Treatment of venous trophic ulcers, using echoscleroobliteration of perforant veins].

    Science.gov (United States)

    Rusyn, V I; Korsak, V V; Boldizhar, P O; Borsenko, M I; Mytrovka, B A

    2014-02-01

    In 36 patients, suffering trophic ulcers on a chronic venous insufficiency background in a decompensated stage (C6 in accordance to CEAP), echoscleroobliteration of perforant veins, using a "foam-form" method in accordance to Tessari, was performed. In 29 patients postrombophlebitic syndrome in incomplete recanalization stage was diagnosed, in 7 recurrence of varicose disease of the lower extremities. In all the patients during echoscleroobliteration there was possible to obliterate the insufficient perforant veins, in 3 patients two perforant veins were obliterated in each of them. In a one week a pathological blood flow along perforant veins, in accordance to data of ultrasound duplex scanning, was absent. This effect lasted during 6 mo in 29 (80.6%) patients. In 25 (69.4%) patients a trophic ulcers healing was achieved in 1 - 3 mo. In a one year in 30 (83.3%) patients a stable obliteration was noted, in 3 (8.3%) - partial recanalization, in 3 (8.3%) - complete recanalization of perforant veins.

  2. Mercury sources and trophic ecology for Hawaiian bottomfish.

    Science.gov (United States)

    Sackett, Dana K; Drazen, Jeffrey C; Choy, C Anela; Popp, Brian; Pitz, Gerald L

    2015-06-02

    In Hawaii, some of the most important commercial and recreational fishes comprise an assemblage of lutjanids and carangids called bottomfish. Despite their importance, we know little about their trophic ecology or where the mercury (Hg) that ultimately resides in their tissue originates. Here we investigated these topics, by analyzing muscle samples for mercury content, nitrogen, carbon, and amino acid specific nitrogen isotope ratios in six species distributed across different depths from the Northwestern Hawaiian Islands (NWHI) and the Main Hawaiian Islands (MHI). Fishes had different sources of nitrogen and carbon, with isotopic values suggesting benthic food sources for shallow nearshore species. High trophic position lutjanids that foraged in deeper water, benthic environments generally had higher Hg levels. Model results also suggested that benthic Hg methylation was an important source of Hg for shallow benthic feeders, while deepwater sources of mercury may be important for those with a diet that derives, at least in part, from the pelagic environment. Further, despite the lack of freshwater sources of Hg in the NWHI, statistical models explaining the variation in tissue Hg in the MHI and NWHI were nearly identical, suggesting freshwater Hg inputs were not a major source of Hg in fish tissue.

  3. Global change in the trophic functioning of marine food webs.

    Directory of Open Access Journals (Sweden)

    Aurore Maureaud

    Full Text Available The development of fisheries in the oceans, and other human drivers such as climate warming, have led to changes in species abundance, assemblages, trophic interactions, and ultimately in the functioning of marine food webs. Here, using a trophodynamic approach and global databases of catches and life history traits of marine species, we tested the hypothesis that anthropogenic ecological impacts may have led to changes in the global parameters defining the transfers of biomass within the food web. First, we developed two indicators to assess such changes: the Time Cumulated Indicator (TCI measuring the residence time of biomass within the food web, and the Efficiency Cumulated Indicator (ECI quantifying the fraction of secondary production reaching the top of the trophic chain. Then, we assessed, at the large marine ecosystem scale, the worldwide change of these two indicators over the 1950-2010 time-periods. Global trends were identified and cluster analyses were used to characterize the variability of trends between ecosystems. Results showed that the most common pattern over the study period is a global decrease in TCI, while the ECI indicator tends to increase. Thus, changes in species assemblages would induce faster and apparently more efficient biomass transfers in marine food webs. Results also suggested that the main driver of change over that period had been the large increase in fishing pressure. The largest changes occurred in ecosystems where 'fishing down the marine food web' are most intensive.

  4. Charismatic microfauna alter cyanobacterial production through a trophic cascade

    Science.gov (United States)

    Geange, S. W.; Stier, A. C.

    2010-06-01

    The trophic ecology of cyanobacterial blooms is poorly understood on coral reefs. Blooms of toxic cyanobacteria, Lyngbya majuscula, can quickly form large mats. The herbivorous sea hare, Stylocheilus striatus, and the predatory nudibranch, Gymnodoris ceylonica, often associate with these blooms, forming a linear food chain: nudibranch—sea hare—cyanobacteria. Using laboratory studies, this study quantified (1) the functional response of nudibranchs, (2) the effect of sea hare size on predation rates, and (3) the strength of the indirect effect of sea hare predation on cyanobacteria (i.e., a trophic cascade). Nudibranchs consumed on average 2.4 sea hares d-1, with the consumption of small sea hares 22 times greater than the consumption of large sea hares. Predation of sea hares reduced herbivory. Cyanobacterial biomass was 1.5 times greater when nudibranchs were present relative to when nudibranchs were absent. Although sea hare grazing can substantially reduce cyanobacterial biomass, predation of sea hares may mitigate grazing pressure, and therefore increase the abundance of cyanobacteria.

  5. High fishery catches through trophic cascades in China.

    Science.gov (United States)

    Szuwalski, Cody S; Burgess, Matthew G; Costello, Christopher; Gaines, Steven D

    2017-01-24

    Indiscriminate and intense fishing has occurred in many marine ecosystems around the world. Although this practice may have negative effects on biodiversity and populations of individual species, it may also increase total fishery productivity by removing predatory fish. We examine the potential for this phenomenon to explain the high reported wild catches in the East China Sea-one of the most productive ecosystems in the world that has also had its catch reporting accuracy and fishery management questioned. We show that reported catches can be approximated using an ecosystem model that allows for trophic cascades (i.e., the depletion of predators and consequent increases in production of their prey). This would be the world's largest known example of marine ecosystem "engineering" and suggests that trade-offs between conservation and food production exist. We project that fishing practices could be modified to increase total catches, revenue, and biomass in the East China Sea, but single-species management would decrease both catches and revenue by reversing the trophic cascades. Our results suggest that implementing single-species management in currently lightly managed and highly exploited multispecies fisheries (which account for a large fraction of global fish catch) may result in decreases in global catch. Efforts to reform management in these fisheries will need to consider system wide impacts of changes in management, rather than focusing only on individual species.

  6. Ecosystem structure and trophic analysis of Angolan fishery landings

    Directory of Open Access Journals (Sweden)

    Ronaldo Angelini

    2011-06-01

    Full Text Available Information on the mean trophic level of fishery landings in Angola and the output from a preliminary Ecopath with Ecosim (EwE model were used to examine the dynamics of the Angolan marine ecosystem. Results were compared with the nearby Namibian and South African ecosystems, which share some of the exploited fish populations. The results show that: (i The mean trophic level of Angola’s fish landings has not decreased over the years; (ii There are significant correlations between the landings of Angola, Namibia and South Africa; (iii The ecosystem attributes calculated by the EwE models for the three ecosystems were similar, and the main differences were related to the magnitude of flows and biomass; (iv The similarity among ecosystem trends for Namibia, South Africa and Angola re-emphasizes the need to continue collaborative regional studies on the fish stocks and their ecosystems. To improve the Angolan model it is necessary to gain a better understanding of plankton dynamics because plankton are essential for Sardinella spp. An expanded analysis of the gut contents of the fish species occupying Angola’s coastline is also necessary.

  7. Effect of pyrethroid treatment against sea lice in salmon farming regarding consumers' health

    OpenAIRE

    Aznar-Alemany, Òscar; Eljarrat, Ethel; Barceló, Damià

    2017-01-01

    Pyrethroids are the most popular drug against sea lice in salmon farming. Although they are more toxic to insects, they have toxic effects in mammals. Pyrethroids were detected in 100% of farmed salmon with a mean concentration of 1.31 ± 1.39 ng g−1 ww and in 50% of wild salmon with a mean of 0.02 ± 0.03 ng g−1 ww. Cypermethrin and deltamethrin, the active ingredients of anti-sea lice formulations, represented 77   ±  27% of the total contamination of farmed salmon. Although farmed salmon had...

  8. The effect of light on the settlement of the salmon louse, Lepeophtheirus salmonis, on Atlantic salmon, Salmo salar L.

    Science.gov (United States)

    Browman, H I; Boxaspen, K; Kuhn, P

    2004-12-01

    The salmon louse, Lepeophtheirus salmonis, is an ectoparasitic copepod that infests both wild and farmed salmonid fish. Salmon lice are a major disease problem in the farming of Atlantic salmon, Salmo salar L., and the possibility of salmon lice playing a role in the decline of wild anadromous stocks has also been raised. Lepeophtheirus salmonis can detect a range of stimuli (pressure/moving water, chemicals and light) in the external environment. However, the response thresholds to various stimuli, and the spatial and temporal scales over which they operate in the context of host location, are largely unknown. In this context, we attempted to determine whether salmon lice copepodids settle onto hosts more effectively, or at different locations on the fish's body, under different qualities of light. Lice settlement trials were conducted under three lighting conditions; L1: unpolarized under ultraviolet A (UVA)-through visible; L2: unpolarized without UVA (control); L3: 100% linearly polarized without UVA. A dark control was also conducted. No statistically significant difference in lice settlement was found. While changes in light intensity are involved in host detection at spatial scales on the order of metres, the results presented here suggest that it is not the primary sensory modality underlying host location at smaller spatial scales (cm to mm).

  9. Evaluation of fast green FCF dye for non-lethal detection of integumental injuries in juvenile chinook salmon oncorhynchus tshawytscha

    Science.gov (United States)

    Elliott, D.G.; Conway, C.M.; Applegate, L.M.J.

    2009-01-01

    A rapid staining procedure for detection of recent skin and fin injuries was tested in juvenile Chinook salmon Oncorhynchus tshawytscha. Immersion of anesthetized fish for 1 min in aerated aqueous solutions of the synthetic food dye fast green FCF (Food Green 3) at concentrations of 0.1 to 0.5% produced consistent and visible staining of integumental injuries. A 0.1% fast green concentration was satisfactory for visual evaluation of injuries, whereas a 0.5% concentration was preferable for digital photography. A rinsing procedure comprised of two 30 s rinses in fresh water was most effective for removal of excess stain after exposure of fish. Survival studies in fresh water and seawater and histopathological analyses indicated that short exposures to aqueous solutions of fast green were non-toxic to juvenile Chinook salmon. In comparisons of the gross and microscopic appearance of fish exposed to fast green at various times after injury, the dye was observed only in areas of the body where epidermal disruption was present as determined by scanning electron microscopy. No dye was observed in areas where epidermal integrity had been restored. Further comparisons showed that fast green exposure produced more consistent and intense staining of skin injury sites than a previously published procedure using trypan blue. Because of its relatively low cost, ease of use and the rapid and specific staining of integumental injuries, fast green may find widespread application in fish health and surface injury evaluations. ?? Inter-Research 2009.

  10. THE TROPHIC LINKS OF DRAGONFLIES (ODONATA IN BIOCENOSES OF THE СENTRAL СAUCASUS

    Directory of Open Access Journals (Sweden)

    Kh. A. Ketenchiev

    2011-01-01

    Full Text Available The trophic links of dragonflies in biocenoses of the Central Caucasus are examined in this article. The analysis of this phenomenon allowed to reveal the spectrum of the given connection of imago and larva’s members of the order Odonata in the communities of the study area. The structure of the trophic links is represented in the form of diagrams.

  11. Longer Food Chains in Pelagic Ecosystems: Trophic Energetics of Animal Body Size and Metabolic Efficiency.

    Science.gov (United States)

    McGarvey, Richard; Dowling, Natalie; Cohen, Joel E

    2016-07-01

    Factors constraining the structure of food webs can be investigated by comparing classes of ecosystems. We find that pelagic ecosystems, those based on one-celled primary producers, have longer food chains than terrestrial ecosystems. Yet pelagic ecosystems have lower primary productivity, contrary to the hypothesis that greater energy flows permit higher trophic levels. We hypothesize that longer food chain length in pelagic ecosystems, compared with terrestrial ecosystems, is associated with smaller pelagic animal body size permitting more rapid trophic energy transfer. Assuming negative allometric dependence of biomass production rate on body mass at each trophic level, the lowest three pelagic animal trophic levels are estimated to add biomass more rapidly than their terrestrial counterparts by factors of 12, 4.8, and 2.6. Pelagic animals consequently transport primary production to a fifth trophic level 50-190 times more rapidly than animals in terrestrial webs. This difference overcomes the approximately fivefold slower pelagic basal productivity, energetically explaining longer pelagic food chains. In addition, ectotherms, dominant at lower pelagic animal trophic levels, have high metabolic efficiency, also favoring higher rates of trophic energy transfer in pelagic ecosystems. These two animal trophic flow mechanisms imply longer pelagic food chains, reestablishing an important role for energetics in food web structure.

  12. TYPES OF SALT MARSH EDGE AND EXPORT OF TROPHIC ENERGY FROM MARSHES TO DEEPER HABITATS

    Science.gov (United States)

    We quantified nekton and estimated trophic export at salt marshes with both erosional and depositional edges at the Goodwin Islands (York River, Virginia, USA). At depositional-edge marshes, we examined trophic flows through quantitative sampling with 1.75 m2 drop rings, and thro...

  13. Trophic niche of squids: Insights from isotopic data in marine systems worldwide

    Science.gov (United States)

    Navarro, Joan; Coll, Marta; Somes, Christoper J.; Olson, Robert J.

    2013-10-01

    Cephalopods are an important prey resource for fishes, seabirds, and marine mammals, and are also voracious predators on crustaceans, fishes, squid and zooplankton. Because of their high feeding rates and abundance, squids have the potential to exert control on the recruitment of commercially important fishes. In this review, we synthesize the available information for two intrinsic markers (δ15N and δ13C isotopic values) in squids for all oceans and several types of ecosystems to obtain a global view of the trophic niches of squids in marine ecosystems. In particular, we aimed to examine whether the trophic positions and trophic widths of squid species vary among oceans and ecosystem types. To correctly compare across systems, we adjusted squid δ15N values for the isotopic variability of phytoplankton at the base of the food web provided by an ocean circulation-biogeochemistry-isotope model. Studies that focused on the trophic ecology of squids using isotopic techniques were few, and most of the information on squids was from studies on their predators. Our results showed that squids occupy a large range of trophic positions and exploit a large range of trophic resources, reflecting the versatility of their feeding behavior and confirming conclusions from food-web models. Clear differences in both trophic position and trophic width were found among oceans and ecosystem types. The study also reinforces the importance of considering the natural variation in isotopic values when comparing the isotopic values of consumers inhabiting different ecosystems.

  14. Invasive plant architecture alters trophic interactions by changing predator abundance and behavior

    Science.gov (United States)

    Dean E. Pearson

    2009-01-01

    As primary producers, plants are known to influence higher trophic interactions by initiating food chains. However, as architects, plants may bypass consumers to directly affect predators with important but underappreciated trophic ramifications. Invasion of western North American grasslands by the perennial forb, spotted knapweed (Centaurea maculosa...

  15. Impact of trophic state on the distribution of intact polar lipids in surface waters of lakes

    NARCIS (Netherlands)

    Bale, N.J.; Hopmans, E.C.; Schoon, P.; de Kluijver, A.; Downing, J.A.; Middelburg, J.J.; Sinninghe Damsté, J.S.; Schouten, S.

    2016-01-01

    We characterized the intact polar lipid (IPL) composition in the surface waters of 22 lakes from Minnesota and Iowa, ranging in trophic state between eutrophic and oligo-mesotrophic, to investigate the impact of trophic state on IPL composition. A high diversity of IPL classes was detected. Most IPL

  16. Host-plant species modifies the diet of an omnivore feeding on three trophic levels

    NARCIS (Netherlands)

    Magalhães, S.; Janssen, A.; Montserrat, M.; Sabelis, M.W.

    2005-01-01

    The diet choice of omnivores feeding on two adjacent trophic levels (either plants and herbivores or herbivores and predators) has been studied extensively. However, omnivores usually feed on more than two trophic levels, and this diet choice and its consequences for population dynamics have hardly

  17. Baseline identification in stable -isotope studies of temperate lotic systems and implications for calculated trophic positions

    DEFF Research Database (Denmark)

    Kristensen, Peter Brinkmann; Riis, Tenna; Dylmer, Hans Erik

    2016-01-01

    in the catchment and had a slope deviating from zero for both fish species, despite gut content analysis revealed no such trophic level dependency of land use. This suggests that Baetidae are not good baseline indicators of trophic position, perhaps because their main food item (periphyton) may include nitrogen-fixing...

  18. Salmon calcitonin: conformational changes and stabilizer effects

    Directory of Open Access Journals (Sweden)

    Shan-Yang Lin

    2015-11-01

    Full Text Available The therapeutic activity of peptides or protein drugs is highly dependent on their conformational structure. The protein structure is flexible and responds to external conditions, which may compromise the protein's native conformation and influence its physical and chemical stability. The physical and chemical stability of peptides or protein drugs are important characteristics of biopharmaceutical products. Calcitonin (CT is a polypeptide hormone that participates in diverse physiological functions in humans; therefore, it is a potentially useful protein for investigations of different aspects of pharmacology and drug delivery systems. Of the different types of CT available for clinical use, salmon CT (sCT is one of the most potent. In this review article, the commercially available sCT was selected as a suitable peptide candidate for the discussion of its stability and conformational changes in the aqueous and solid states using Fourier transform infrared (FTIR spectroscopic analysis under different external conditions, including pH, temperature, drying method, and added excipients. Particularly, excipients that have been optimized as stabilizers of sCT in aqueous solution and as lyophilized and spray-dried drug formulations are also discussed.

  19. Process analysis and data driven optimization in the salmon industry

    DEFF Research Database (Denmark)

    Johansson, Gine Ørnholt

    was observed. To the best of my knowledge, no study has reported this previously, and this observation thus segregates from the commonly accepted statement that protein content is a stable parameter in farmed salmon muscle. In the work related to the texture of salmon a model that can predict peak force...... category of the salmon based on protein profile has been explored. The potential effect of the current project was expected to result both in a higher share of products of the highest possible quality, and allocation of products to match raw material to optimal product recipe (for example fillet, portion...... of additional meat a year with a value of 2 million Danish kroner. Furthermore, throughout the project data was gathered covering a total of 11 months in order to investigate the variation in quality parameters. A significant negative correlation between sea temperature at the rearing region and protein content...

  20. GABAergic anxiolytic drug in water increases migration behaviour in salmon

    Science.gov (United States)

    Hellström, Gustav; Klaminder, Jonatan; Finn, Fia; Persson, Lo; Alanärä, Anders; Jonsson, Micael; Fick, Jerker; Brodin, Tomas

    2016-12-01

    Migration is an important life-history event in a wide range of taxa, yet many migrations are influenced by anthropogenic change. Although migration dynamics are extensively studied, the potential effects of environmental contaminants on migratory physiology are poorly understood. In this study we show that an anxiolytic drug in water can promote downward migratory behaviour of Atlantic salmon (Salmo salar) in both laboratory setting and in a natural river tributary. Exposing salmon smolt to a dilute concentration of a GABAA receptor agonist (oxazepam) increased migration intensity compared with untreated smolt. These results implicate that salmon migration may be affected by human-induced changes in water chemical properties, such as acidification and pharmaceutical residues in wastewater effluent, via alterations in the GABAA receptor function.

  1. Evidence for a Peripheral Olfactory Memory in Imprinted Salmon

    Science.gov (United States)

    Nevitt, Gabrielle A.; Dittman, Andrew H.; Quinn, Thomas P.; Moody, William J., Jr.

    1994-05-01

    The remarkable homing ability of salmon relies on olfactory cues, but its cellular basis is unknown. To test the role of peripheral olfactory receptors in odorant memory retention, we imprinted coho salmon (Oncorhynchus kisutch) to micromolar concentrations of phenyl ethyl alcohol during parr-smolt transformation. The following year, we measured phenyl ethyl alcohol responses in the peripheral receptor cells using patch clamp. Cells from imprinted fish showed increased sensitivity to phenyl ethyl alcohol compared either to cells from naive fish or to sensitivity to another behaviorally important odorant (L-serine). Field experiments verified an increased behavioral preference for phenyl ethyl alcohol by imprinted salmon as adults. Thus, some component of the imprinted olfactory homestream memory appears to be retained peripherally.

  2. Modeling the Transmission of Piscirickettsia salmonis in Farmed Salmon

    Science.gov (United States)

    Cisternas, Jaime; Moreno, Adolfo

    2007-05-01

    Farming Atlantic salmon is an economic activity of growing relevance in the southern regions of Chile. The need to increase efficiency and reach production goals, as well as restrictions on the use of water resources, had led in recent years to certain practices that proved prone to bacterial infections among the fish. Our study focuses on the impact of rickettsial bacteria in farmed salmon, and the possibility of controlling its incidence once it is established along the salmon life cicle. We used compartmental models to separate fish in their maturation stages and health status. The mathematical analysis will involve differential equations with and without delays, and linear stability principles. Our goal was to build a simple model that explains the basic mechanisms at work and provides predictions on the outcome of different control strategies.

  3. Salmon, Science, and Reciprocity on the Northwest Coast

    Directory of Open Access Journals (Sweden)

    D. Bruce Johnsen

    2009-12-01

    Full Text Available Severe depletion of many genetically distinct Pacific salmon populations has spawned a contentious debate over causation and the efficacy of proposed solutions. No doubt the precipitating factor was overharvesting of the commons beginning along the Northwest Coast around 1860. Yet, for millenia before that, a relatively dense population of Indian tribes managed salmon stocks that have since been characterized as "superabundant." This study investigates how they avoided a tragedy of the commons, where in recent history, commercial ocean fishers guided by scientifically informed regulators, have repeatedly failed. Unlike commercial fishers, the tribes enjoyed exclusive rights to terminal fisheries enforced through rigorous reciprocity relations. The available evidence is compelling that they actively husbanded their salmon stocks for sustained abundance.

  4. Efficacy and toxicity of iodine disinfection of Atlantic salmon eggs

    Science.gov (United States)

    Chalupnicki, M.A.; Ketola, H.G.; Starliper, C.E.; Gallagher, D.

    2011-01-01

    Recent interest in the restoration of Atlantic salmon Salmo salar in the Great Lakes has given rise to new culture techniques and management programs designed to reduce pathogen transmission while stabilizing and enhancing wild populations. We examined the toxicity of iodine to Atlantic salmon eggs and its effectiveness as a disinfectant against bacteria on egg surfaces. We spawned and fertilized eight gravid Atlantic salmon from Cayuga Lake, New York, and exposed their eggs to 10 concentrations of iodine (5, 10, 50, 75, 100, 500, 750, 1,000, 5,000, and 7,500 mg/L) for 30 min during water hardening. An additional subsample of unfertilized eggs was also exposed to some of the same concentrations of iodine (5, 10, 50, 75, and 100 mg/L) to determine the efficiency of disinfection. Viable eggs were only obtained from four females. Survival of eggs to the eyed stage and hatch tended to be reduced at iodine concentrations of 50 and 75 mg/L and was significantly reduced at concentrations of 100 mg/L iodine or more. We calculated the concentrations of iodine that killed 50% of the Atlantic salmon eggs at eye-up and hatch to be 175 and 85 mg/L, respectively. Aeromonas veronii, A. schubertii, A. hydrophila, A. caviae, Plesiomonas shiggeloides, and Citrobacter spp. were the predominant bacteria present on the surface of green eggs and were significantly reduced by an iodine immersion. The use of iodine as a disinfectant on Atlantic salmon eggs was effective at low concentrations (50–75 mg/L), for which toxicity to Atlantic salmon was minimal.

  5. Quantitative gradient of subsidies reveals a threshold in community-level trophic cascades.

    Science.gov (United States)

    Klemmer, Amanda J; Richardson, John S

    2013-09-01

    Evidence varies on how subsidies affect trophic cascades within recipient food webs. This could be due to complex nonlinearities being masked by single-level manipulations (presence/absence) of subsidies in past studies. We predicted that trophic cascade strength would increase nonlinearly across a gradient of subsidies. We set out to reveal these complex, nonlinear relationships through manipulating a quantitative gradient of detrital subsidies to lake benthic food webs along with the presence/absence of trout. Contrary to our prediction, we found that trophic cascades only occurred at low subsidy levels, disappearing as subsidies increased. This threshold in trophic cascade strength may be due to an increase in intermediate predators in the absence of top predators, as well as changes in the proportion of armored vs. un-armored primary consumers. Future studies on the effect of subsidies on trophic cascade strength need to incorporate naturally occurring gradients to reveal the complex direct and indirect interactions within food webs.

  6. Intersexual Trophic Niche Partitioning in an Ant-Eating spider (Araneae: Zodariidae)

    DEFF Research Database (Denmark)

    Pekár, Stanislav; Martisová, Martina; Bilde, T.

    2011-01-01

    lead to higher energy demands in females driven by fecundity selection, while males invest in mate searching. We tested predictions of the two hypotheses underlying intersexual trophic niche partitioning in a natural population of spiders. Zodarion jozefienae spiders specialize on Messor barbarus ants...... that are polymorphic in body size and hence comprise potential trophic niches for the spider, making this system well-suited to study intersexual trophic niche partitioning. Methodology/Principal Findings Comparative analysis of trophic morphology (the chelicerae) and body size of males, females and juveniles...... demonstrated highly female biased SSD (Sexual Size Dimorphism) in body size, body weight, and in the size of chelicerae, the latter arising from sex-specific growth patterns in trophic morphology. In the field, female spiders actively selected ant sub-castes that were larger than the average prey size...

  7. Genetic programs of the developing tuberal hypothalamus and potential mechanisms of their disruption by environmental factors.

    Science.gov (United States)

    Nesan, Dinushan; Kurrasch, Deborah M

    2016-12-15

    The hypothalamus is a critical regulator of body homeostasis, influencing the autonomic nervous system and releasing trophic hormones to modulate the endocrine system. The developmental mechanisms that govern formation of the mature hypothalamus are becoming increasingly understood as research in this area grows, leading us to gain appreciation for how these developmental programs are susceptible to disruption by maternal exposure to endocrine disrupting chemicals or other environmental factors in utero. These vulnerabilities, combined with the prominent roles of the various hypothalamic nuclei in regulating appetite, reproductive behaviour, mood, and other physiologies, create a window whereby early developmental disruption can have potent long-term effects. Here we broadly outline our current understanding of hypothalamic development, with a particular focus on the tuberal hypothalamus, including what is know about nuclear coalescing and maturation. We finish by discussing how exposure to environmental or maternally-derived factors can perhaps disrupt these hypothalamic developmental programs, and potentially lead to neuroendocrine disease states. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  8. Control of biological hazards in cold smoked salmon production

    DEFF Research Database (Denmark)

    Huss, Hans Henrik; Embarek, Peter Karim Ben; Jeppesen, V.F.

    1995-01-01

    An outline of the common processing technology for cold smoked salmon in Denmark is presented. The safety hazards related to pathogenic bacteria, parasites and biogenic amines are discussed with special emphasis on hazards related to Clostridium botulinum and Listeria monocytogenes. Critical...... control points are identified for all hazards except growth of L. monocytogenes. For this reason a limitation of shelf life to three weeks at +5 degrees C far cold smoked vacuum-packed salmon having greater than or equal to 3% water phase salt is recommended...

  9. Price premium of organic salmon in Danish retail sale

    DEFF Research Database (Denmark)

    Ankamah Yeboah, Isaac; Nielsen, Max; Nielsen, Rasmus

    2016-01-01

    for organic salmon in Danish retail sale using consumer panel scanner data from households by applying a random effect hedonic price model that permits unobserved household heterogeneity. A price premium of 20% was identified for organic salmon. The magnitude of this premium is comparable to organic labeled......The year 2016 will be pivotal for organic aquaculture producers in EU, because it represents the deadline for implementing the complete organic life cycle in aquaculture production. Depending on the sturdiness of farms already producing, such a shift in the industry may affect production costs...

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

    Science.gov (United States)

    Rinella, Daniel J.; Wipfli, Mark S.; Stricker, Craig A.; Heintz, Ron A.; Rinella, Matthew J.

    2012-01-01

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

  11. Inclusion of Palmaria palmata (red seaweed) in Atlantic salmon diets: effects on the quality, shelf-life parameters and sensory properties of fresh and cooked salmon fillets.

    Science.gov (United States)

    Moroney, Natasha C; Wan, Alex H L; Soler-Vila, Anna; FitzGerald, Richard D; Johnson, Mark P; Kerry, Joe P

    2015-03-30

    The use of Palmaria palmata (PP) as a natural ingredient in farmed Atlantic salmon diets was investigated. The effect of salmon diet supplementation with P. palmata (0, 5, 10 and 15%) or synthetic astaxanthin (positive control, PC) for 16 weeks pre-slaughter on quality indices of fresh salmon fillets was examined. The susceptibility of salmon fillets/homogenates to oxidative stress conditions was also measured. In salmon fillets stored in modified atmosphere packs (60% N2 /40% CO2 ) for up to 15 days at 4 °C, P. palmata increased surface -a* (greenness) and b* (yellowness) values in a dose-dependent manner, resulting in a final yellow/orange flesh colour. In general, the dietary addition of P. palmata had no effect on pH, lipid oxidation (fresh, cooked and fillet homogenates) and microbiological status. 'Eating quality' sensory descriptors (texture, odour and oxidation flavour) in cooked salmon fillets were not influenced by dietary P. palmata. Salmon fed 5% PP showed increased overall acceptability compared with those fed PC and 0% PP. Dietary P. palmata was ineffective at providing red coloration in salmon fillets, but pigment deposition enhanced fillets with a yellow/orange colour. Carotenoids from P. palmata may prove to be a natural pigment alternative to canthaxanthin in salmon feeds. © 2014 Society of Chemical Industry.

  12. Disruptive Technologies in Higher Education

    Science.gov (United States)

    Flavin, Michael

    2012-01-01

    This paper analyses the role of "disruptive" innovative technologies in higher education. In this country and elsewhere, Higher Education Institutions (HEIs) have invested significant sums in learning technologies, with Virtual Learning Environments (VLEs) being more or less universal, but these technologies have not been universally…

  13. Instability Prediction and Disruption Avoidance

    Science.gov (United States)

    Turnbull, A. D.; Liu, Y. Q.; Hanson, J. M.; Turco, F.; Ferraro, N. M.

    2017-10-01

    Disruption avoidance requires both a prediction of the instability proximity and an estimate of the `disruptability' - the likelihood that the instability will ultimately result in a disruptive event. MHD spectroscopy is a promising option for obtaining information on the proximity of instabilities. Both the direct response and the antenna impedance provide valuable information on the low frequency global normal modes corresponding to stabilized kink modes. Data from DIII-D experiments and available nonlinear simulations are used to define quantitative criteria that signify when instabilities ultimately disrupt and when they saturate or dissipate. The key distinction in this approach is the use of physical characteristics of the modes rather than more accessible operation parameters. Simple characteristics of the linear instability for example include the linear growth or damping rate and the mode spatial extent. Criteria can also involve identifying sources of free energy in the nonlinear evolution. Work supported in part by the US DOE under DE-FC02-04ER54698 & DE-FG02-95ER54309.

  14. Disruptive Innovation in Healthcare & Rehabilitation

    DEFF Research Database (Denmark)

    Brooks, Anthony Lewis

    2014-01-01

    Disruption is a powerful body of theory that describes how people interact and react, how behavior is shaped, how organizational cultures form and influence decisions. Innovation is the process of translating an idea or invention into a product or service that creates value or for which customers...

  15. Marital Alternatives and Marital Disruption.

    Science.gov (United States)

    Udry, J. Richard

    1981-01-01

    Explores the usefulness of "marital alternatives" as a dimension in explaining marital stability, using longitudinal data from a panel of married, White, urban couples from 16 urban areas. Results indicated the dimension of marital alternatives appeared to be a better predictor of marital disruption than marital satisfaction. (Author/RC)

  16. Vortex disruption by magnetohydrodynamic feedback

    Science.gov (United States)

    Mak, J.; Griffiths, S. D.; Hughes, D. W.

    2017-11-01

    In an electrically conducting fluid, vortices stretch out a weak, large-scale magnetic field to form strong current sheets on their edges. Associated with these current sheets are magnetic stresses, which are subsequently released through reconnection, leading to vortex disruption, and possibly even destruction. This disruption phenomenon is investigated here in the context of two-dimensional, homogeneous, incompressible magnetohydrodynamics. We derive a simple order of magnitude estimate for the magnetic stresses—and thus the degree of disruption—that depends on the strength of the background magnetic field (measured by the parameter M , a ratio between the Alfvén speed and a typical flow speed) and on the magnetic diffusivity (measured by the magnetic Reynolds number Rm ). The resulting estimate suggests that significant disruption occurs when M2Rm =O (1 ) . To test our prediction, we analyze direct numerical simulations of vortices generated by the breakup of unstable shear flows with an initially weak background magnetic field. Using the Okubo-Weiss vortex coherence criterion, we introduce a vortex disruption measure, and show that it is consistent with our predicted scaling, for vortices generated by instabilities of both a shear layer and a jet.

  17. The Influence of Salmon Recolonization on Riparian Communities in the Cedar River, Washington, USA

    Science.gov (United States)

    Moravek, J.; Clipp, H.; Kiffney, P.

    2015-12-01

    Salmon are a valuable cultural and economic resource throughout the Pacific Northwest, but increasing human activity is degrading coastal ecosystems and threatening local salmon populations. Salmon conservation efforts often focus on habitat restoration, including the re-colonization of salmon into historically obstructed areas such as the Cedar River in Washington, USA. However, to assess the implications of salmon re-colonization on a landscape scale, it is critical to consider not only the river ecosystem but also the surrounding riparian habitat. Although prior studies suggest that salmon alter riparian food web dynamics, the riparian community on the Cedar River has not yet been characterized. To investigate possible connections between salmon and the riparian habitat, we surveyed riparian spider communities along a gradient of salmon inputs (g/m2). In 10-m transects along the banks of the river, we identified spiders and spider webs, collected prey from webs, and characterized nearby aquatic macroinvertebrate communities. We found that the density of aquatic macroinvertebrates, as well as the density of spider prey, both had significant positive relationships with salmon inputs, supporting the hypothesis that salmon provide energy and nutrients for both aquatic and riparian food webs. We also found that spider diversity significantly decreased with salmon inputs, potentially due to confounding factors such as stream gradient or vegetation structure. Although additional information is needed to fully understand this relationship, the significant connection between salmon inputs and spider diversity is compelling motivation for further studies regarding the link between aquatic and riparian systems on the Cedar River. Understanding the connections between salmon and the riparian community is critical to characterizing the landscape-scale implications of sustainable salmon management in the Pacific Northwest.

  18. Trophic pathways and carbon flux patterns in the Laptev Sea

    Science.gov (United States)

    Schmid, Michael K.; Piepenburg, Dieter; Golikov, Alexander A.; Juterzenka, Karen von; Petryashov, Victor V.; Spindler, Michael

    2006-10-01

    The Laptev Sea is a high-Arctic epicontinental sea north of Siberia (Russia) that is one of the least understood regions of the world’s ocean. It is characterized by a shallow and broad shelf plateau, high influx of river water, sediments and nutrients during summer, long-lasting sea-ice cover from October to May, and the formation of a narrow flaw-lead polynya off the fast-ice edge during winter. Here, we describe results of a German-Russian research project (1993-present), presenting the distribution patterns and dynamics of its marine flora and fauna, as well as pathways and processes of coupling between sea-ice, water-column and sea-floor biota. Three ecological zones are distinguished along a combined east-west and Lena-impact gradient, differing in the composition of pelagic and benthic communities. In general, high Chl a concentrations in the sediments indicate a tight coupling between sympagic and pelagic primary production and nutrient supply to the benthos throughout the entire Laptev Sea. However, there were pronounced regional differences between the ecological zones in magnitude of primary production and trophic dynamics. Primary production during the ice-free summer was highest in the estuarine zone most strongly influenced by the Lena River (210 mg C m -2 day -1). The western and northeastern Laptev Sea yielded 55 and 95 mg C m -2 day -1, respectively. Moreover, the zones differed in the partitioning of carbon flux between zooplankton and benthic food webs. In the Lena zone zooplankton carbon demand was about 31 mg C m -2 day -1 whereas in the western zone it was 21 mg C m -2 day -1 and in the eastern zone 4 mg C m -2 day -1. Total benthic carbon demand was 32 mg C m -2 day -1 for the Lena zone, 56 mg C m -2 day -1 in the western zone and 100 mg C m -2 day -1 in the northeastern zone. A carbon budget constructed for the Laptev Sea indicates that (1) a high proportion of primary production is channelled through the benthic trophic web, bypassing the

  19. Megaherbivores influence trophic guilds structure in African ungulate communities.

    Science.gov (United States)

    Fritz, Hervé; Duncan, Patrick; Gordon, Iain J; Illius, Andrew W

    2002-05-01

    We used a data set of ungulate censuses from 31 natural ecosystems from East and Southern Africa to test two hypotheses: (1) megaherbivores should dominate ungulate communities in ecosystems with high rainfall and low soil nutrient status because of their ability to survive on poor quality food resources, and (2) the abundance of megaherbivores affects the abundance of the mesoherbivores, distinguishing the different feeding guilds: mesograzers, mesobrowsers and mesomixed feeders. Two axes of a multivariate analysis (77% of the variance) discriminated the sites well, the first separating sites dominated by megaherbivores from those dominated by mesoherbivores, and the second representing a gradient between mesograzers and mesobrowsers. Our analysis shows (1) that megaherbivores can be considered to be a separate trophic guild and (2) that mesograzers and mesobrowsers respond differently to variation in their trophic environments. The metabolic biomass density of megaherbivores increased with annual rainfall, but was not related to soil nutrient status, and as predicted, megaherbivores comprised a larger proportion of the biomass of ungulate communities in ecosystems with high rainfall and low nutrient soils. The metabolic biomass density of mesoherbivores increased with rainfall and soil nutrient status. Within the mesoherbivores, the metabolic biomass density of mesograzers showed the same trend, and seemed unaffected by megaherbivores. Conversely, mesobrowsers and mesomixed feeders appeared to be unaffected by rainfall or soil nutrient status, but mesomixed feeders declined when megaherbivores were abundant. This suggests that megaherbivores may compete with the mesomixed-feeder species for food or they may alter the vegetation communities unfavourably. A similar analysis using elephants alone instead of megaherbivores as a group showed that both mesobrowsers and mesomixed feeders were affected significantly by elephant, which is consistent with the fact that

  20. Effects of aqueous exposure to polychlorinated biphenyls (Aroclor 1254) on physiology and behavior of smolt development of Atlantic salmon

    Science.gov (United States)

    Lerner, D.T.; Bjornsson, Bjorn Thrandur; McCormick, S.D.

    2007-01-01

    Polychlorinated biphenyls (PCBs) are a widespread aquatic contaminant and are present in both wild and hatchery raised Atlantic salmon, Salmo salar. The possible sub-lethal alterations in smolt physiology and behavior due to PCB exposure of salmon have not been widely examined. In this study, we examined the effects of the PCB mixture Aroclor 1254 on survival and smolt development of Atlantic salmon. In separate experiments, fish were exposed as yolk-sac larvae or as juveniles just prior to the parr-smolt transformation in April to 1 ??g l-1 (PCB-1) or 10 ??g l-1 (PCB-10) aqueous Aroclor 1254 (A1254), or vehicle for 21 days. After exposure, yolk-sac larvae were reared at ambient conditions for 1 year, until the peak of smolting the following May. Juveniles were sampled immediately after exposure. Both groups were assessed for behavioral, osmoregulatory, and endocrine disruption of smolt development at the peak of smolting. PCB-1 and PCB-10 treated yolk-sac larvae exhibited significant increases in the rate of opercular movement after 14 and 21 days of exposure. At the peak of smolting, prior exposure as yolk-sac larvae to PCB-1 did not affect behavior, while PCB-10 dramatically decreased volitional preference for seawater. Neither concentration of A1254 had long-term effects on the osmoregulatory or endocrine parameters measured in animals exposed as yolk-sac larvae. Juvenile fish exposed to PCB-1 or PCB-10 during smolting exhibited a dose-dependent reduction in preference for seawater. Fish treated with the higher dose of A1254 also exhibited a 50% decrease in gill Na+,K+-ATPase activity and a 10% decrease in plasma chloride levels in freshwater. In addition, plasma triiodothyronine was reduced 35-50% and plasma cortisol 58% in response to exposure to either concentration; whereas plasma thyroxine, growth hormone, and insulin-like growth factor I levels were unaffected. These results indicate that the effects of exposure to A1254 may vary according to

  1. Captive Rearing Program for Salmon River Chinook Salmon : Project Progress Report, 2001 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Venditti, David A.

    2003-10-01

    During 2001, the Idaho Department of Fish and Game continued to develop techniques to rear chinook salmon Oncorhynchus tshawytscha to sexual maturity in captivity and to monitor their reproductive performance under natural conditions. Eyed-eggs were hydraulically collected from redds in the East Fork Salmon River (EFSR; N = 311) and the West Fork Yankee Fork Salmon River (WFYF; N = 272) to establish brood year 2001 culture cohorts. The eyed-eggs were incubated and reared by family group at the Eagle Fish Hatchery (Eagle). Juveniles collected the previous summer were PIT and elastomer tagged and vaccinated against vibrio Vibrio spp. and bacterial kidney disease prior to the majority of them being transferred to the National Marine Fisheries Service, Manchester Marine Experimental Station for saltwater rearing through maturity. Smolt transfers included 210 individuals from the Lemhi River (LEM), 242 from the WFYF, and 178 from the EFSR. Maturing fish transfers from Manchester to Eagle included 62 individuals from the LEM, 72 from the WFYF, and 27 from the EFSR. Additional water chilling capacity was added at Eagle in 2001 to test if spawn timing could be advanced by temperature manipulations, and adults from the LEM and WFYF were divided into chilled ({approx} 9 C) and ambient ({approx} 13.5 C) water temperature groups while at Eagle. Twenty-five mature females from the LEM (11 chilled, 14 ambient) were spawned in captivity with 23 males with the same temperature history in 2001. Water temperature group was not shown to affect the spawn timing of these females, but males did mature earlier. Egg survival to the eyed stage of development averaged 37.9% and did not differ significantly between the two temperature groups. A total of 8,154 eyed-eggs from these crosses were placed in in-stream incubators by personnel from the Shoshone-Bannock Tribe. Mature adults (N = 89) were released into the WFYF to evaluate their reproductive performance. After release, fish

  2. Biodiversity enhances ecosystem multifunctionality across trophic levels and habitats.

    Science.gov (United States)

    Lefcheck, Jonathan S; Byrnes, Jarrett E K; Isbell, Forest; Gamfeldt, Lars; Griffin, John N; Eisenhauer, Nico; Hensel, Marc J S; Hector, Andy; Cardinale, Bradley J; Duffy, J Emmett

    2015-04-24

    The importance of biodiversity for the integrated functioning of ecosystems remains unclear because most evidence comes from analyses of biodiversity's effect on individual functions. Here we show that the effects of biodiversity on ecosystem function become more important as more functions are considered. We present the first systematic investigation of biodiversity's effect on ecosystem multifunctionality across multiple taxa, trophic levels and habitats using a comprehensive database of 94 manipulations of species richness. We show that species-rich communities maintained multiple functions at higher levels than depauperate ones. These effects were stronger for herbivore biodiversity than for plant biodiversity, and were remarkably consistent across aquatic and terrestrial habitats. Despite observed tradeoffs, the overall effect of biodiversity on multifunctionality grew stronger as more functions were considered. These results indicate that prior research has underestimated the importance of biodiversity for ecosystem functioning by focusing on individual functions and taxonomic groups.

  3. Interacting trophic forcing and the population dynamics of herring

    DEFF Research Database (Denmark)

    Lindegren, Martin; Ostman, Orjan; Gardmark, Anna

    2011-01-01

    Small pelagic fish occupy a central position in marine ecosystems worldwide, largely by determining the energy transfer from lower trophic levels to predators at the top of the food web, including humans. Population dynamics of small pelagic fish may therefore be regulated neither strictly bottom......-up nor top-down, but rather through multiple external and internal drivers. While in many studies single drivers have been identified, potential synergies of multiple factors, as well as their relative importance in regulating population dynamics of small pelagic fish, is a largely unresolved issue....... Using a statistical, age-structured modeling approach, we demonstrate the relative importance and influence of bottom-up (e.g., climate, zooplankton availability) and top-down (i.e., fishing and predation) factors on the population dynamics of Bothnian Sea herring (Clupea harengus) throughout its life...

  4. Biodiversity enhances ecosystem multifunctionality across trophic levels and habitats

    Science.gov (United States)

    Lefcheck, Jonathan S.; Byrnes, Jarrett E. K.; Isbell, Forest; Gamfeldt, Lars; Griffin, John N.; Eisenhauer, Nico; Hensel, Marc J. S.; Hector, Andy; Cardinale, Bradley J.; Duffy, J. Emmett

    2015-01-01

    The importance of biodiversity for the integrated functioning of ecosystems remains unclear because most evidence comes from analyses of biodiversity's effect on individual functions. Here we show that the effects of biodiversity on ecosystem function become more important as more functions are considered. We present the first systematic investigation of biodiversity's effect on ecosystem multifunctionality across multiple taxa, trophic levels and habitats using a comprehensive database of 94 manipulations of species richness. We show that species-rich communities maintained multiple functions at higher levels than depauperate ones. These effects were stronger for herbivore biodiversity than for plant biodiversity, and were remarkably consistent across aquatic and terrestrial habitats. Despite observed tradeoffs, the overall effect of biodiversity on multifunctionality grew stronger as more functions were considered. These results indicate that prior research has underestimated the importance of biodiversity for ecosystem functioning by focusing on individual functions and taxonomic groups. PMID:25907115

  5. Dexamethasone selectively suppresses microglial trophic responses to hippocampal deafferentation

    DEFF Research Database (Denmark)

    Woods, A G; Poulsen, F R; Gall, C M

    1999-01-01

    , possibly by reducing trophic signals that stimulate growth. With an interest in this hypothesis, the present studies evaluated the influence of systemic treatment with the synthetic glucocorticoid dexamethasone on entorhinal lesion-induced increases in neurotrophic factor expression in young adult rat...... hippocampus. Daily dexamethasone injections almost completely blocked increases in insulin-like growth factor-1 messenger RNA content, but did not perturb increases in ciliary neurotrophic factor or basic fibroblast growth factor messenger RNA content, in the deafferented dentate gyrus molecular layer....... To determine if the suppression of insulin-like growth factor-1 expression was secondary to a general inhibition of microglial responses, and to identify the time period of glucocorticoid sensitivity, additional rats were prepared to evaluate the effects of semi-chronic (i.e. daily) and single dexamethasone...

  6. Polluted Pathways: Mechanisms of Metabolic Disruption by Endocrine Disrupting Chemicals.

    Science.gov (United States)

    Mimoto, Mizuho S; Nadal, Angel; Sargis, Robert M

    2017-06-01

    Environmental toxicants are increasingly implicated in the global decline in metabolic health. Focusing on diabetes, herein, the molecular and cellular mechanisms by which metabolism disrupting chemicals (MDCs) impair energy homeostasis are discussed. Emerging data implicate MDC perturbations in a variety of pathways as contributors to metabolic disease pathogenesis, with effects in diverse tissues regulating fuel utilization. Potentiation of traditional metabolic risk factors, such as caloric excess, and emerging threats to metabolism, such as disruptions in circadian rhythms, are important areas of current and future MDC research. Increasing evidence also implicates deleterious effects of MDCs on metabolic programming that occur during vulnerable developmental windows, such as in utero and early post-natal life as well as pregnancy. Recent insights into the mechanisms by which MDCs alter energy homeostasis will advance the field's ability to predict interactions with classical metabolic disease risk factors and empower studies utilizing targeted therapeutics to treat MDC-mediated diabetes.

  7. Geophysical investigation, Salmon Site, Lamar County, Mississippi

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-02-01

    Geophysical surveys were conducted in 1992 and 1993 on 21 sites at the Salmon Site (SS) located in Lamar County, Mississippi. The studies are part of the Remedial Investigation/Feasibility Study (RI/FS) being conducted by IT Corporation for the U.S. Department of Energy (DOE). During the 1960s, two nuclear devices and two chemical tests were detonated 826 meters (in) (2710 feet [ft]) below the ground surface in the salt dome underlying the SS. These tests were part of the Vela Uniform Program conducted to improve the United States capability to detect, identify, and locate underground nuclear detonations. The RI/FS is being conducted to determine if any contamination is migrating from the underground shot cavity in the salt dome and if there is any residual contamination in the near surface mud and debris disposal pits used during the testing activities. The objective of the surface geophysical surveys was to locate buried debris, disposal pits, and abandoned mud pits that may be present at the site. This information will then be used to identify the locations for test pits, cone penetrometer tests, and drill hole/monitor well installation. The disposal pits were used during the operation of the test site in the 1960s. Vertical magnetic gradient (magnetic gradient), electromagnetic (EM) conductivity, and ground-penetrating radar (GPR) surveys were used to accomplish these objectives. A description of the equipment used and a theoretical discussion of the geophysical methods are presented Appendix A. Because of the large number of figures relative to the number of pages of text, the geophysical grid-location maps, the contour maps of the magnetic-gradient data, the contour maps of the EM conductivity data, and the GPR traverse location maps are located in Appendix B, Tabs I through 22. In addition, selected GPR records are located in Appendix C.

  8. Ecosystem Responses To Plant Phenology Across Scales And Trophic Levels

    Science.gov (United States)

    Stoner, D.; Sexton, J. O.; Nagol, J. R.; Ironside, K.; Choate, D.; Longshore, K.; Edwards, T., Jr.

    2015-12-01

    Plant phenology in arid and semi-arid ecoregions is constrained by water availability and governs the life history characteristics of primary and secondary consumers. We related the behavior, demography, and distribution of mammalian herbivores and their principal predator to remotely sensed vegetation and climatological indices across the western United States for the period 2000-2014. Across scales, terrain and topographic position moderates the effects of climatological drought on primary productivity, resulting in differential susceptibility among plant functional types to water stress. At broad scales, herbivores tie parturition to moist sites during the period of maximum increase in local forage production. Consequently, juvenile mortality is highest in regions of extreme phenological variability. Although decoupled from primary production by one or more trophic levels, carnivore home range size and density is negatively correlated to plant productivity and growing season length. At the finest scales, predation influences the behavior of herbivore prey through compromised habitat selection, in which maternal females trade nutritional benefits of high plant biomass for reduced mortality risk associated with increased visibility. Climate projections for the western United States predict warming combined with shifts in the timing and form of precipitation. Our analyses suggest that these changes will propagate through trophic levels as increased phenological variability and shifts in plant distributions, larger consumer home ranges, altered migration behavior, and generally higher volatility in wildlife populations. Combined with expansion and intensification of human land use across the region, these changes will likely have economic implications stemming from increased human-wildlife conflict (e.g., crop damage, vehicle collisions) and changes in wildlife-related tourism.

  9. Cryptic population dynamics: rapid evolution masks trophic interactions.

    Science.gov (United States)

    Yoshida, Takehito; Ellner, Stephen P; Jones, Laura E; Bohannan, Brendan J M; Lenski, Richard E; Hairston, Nelson G

    2007-09-01

    Trophic relationships, such as those between predator and prey or between pathogen and host, are key interactions linking species in ecological food webs. The structure of these links and their strengths have major consequences for the dynamics and stability of food webs. The existence and strength of particular trophic links has often been assessed using observational data on changes in species abundance through time. Here we show that very strong links can be completely missed by these kinds of analyses when changes in population abundance are accompanied by contemporaneous rapid evolution in the prey or host species. Experimental observations, in rotifer-alga and phage-bacteria chemostats, show that the predator or pathogen can exhibit large-amplitude cycles while the abundance of the prey or host remains essentially constant. We know that the species are tightly linked in these experimental microcosms, but without this knowledge, we would infer from observed patterns in abundance that the species are weakly or not at all linked. Mathematical modeling shows that this kind of cryptic dynamics occurs when there is rapid prey or host evolution for traits conferring defense against attack, and the cost of defense (in terms of tradeoffs with other fitness components) is low. Several predictions of the theory that we developed to explain the rotifer-alga experiments are confirmed in the phage-bacteria experiments, where bacterial evolution could be tracked. Modeling suggests that rapid evolution may also confound experimental approaches to measuring interaction strength, but it identifies certain experimental designs as being more robust against potential confounding by rapid evolution.

  10. Cryptic population dynamics: rapid evolution masks trophic interactions.

    Directory of Open Access Journals (Sweden)

    Takehito Yoshida

    2007-09-01

    Full Text Available Trophic relationships, such as those between predator and prey or between pathogen and host, are key interactions linking species in ecological food webs. The structure of these links and their strengths have major consequences for the dynamics and stability of food webs. The existence and strength of particular trophic links has often been assessed using observational data on changes in species abundance through time. Here we show that very strong links can be completely missed by these kinds of analyses when changes in population abundance are accompanied by contemporaneous rapid evolution in the prey or host species. Experimental observations, in rotifer-alga and phage-bacteria chemostats, show that the predator or pathogen can exhibit large-amplitude cycles while the abundance of the prey or host remains essentially constant. We know that the species are tightly linked in these experimental microcosms, but without this knowledge, we would infer from observed patterns in abundance that the species are weakly or not at all linked. Mathematical modeling shows that this kind of cryptic dynamics occurs when there is rapid prey or host evolution for traits conferring defense against attack, and the cost of defense (in terms of tradeoffs with other fitness components is low. Several predictions of the theory that we developed to explain the rotifer-alga experiments are confirmed in the phage-bacteria experiments, where bacterial evolution could be tracked. Modeling suggests that rapid evolution may also confound experimental approaches to measuring interaction strength, but it identifies certain experimental designs as being more robust against potential confounding by rapid evolution.

  11. Potential trophic cascades triggered by the barred owl range expansion

    Science.gov (United States)

    Holm, Samantha R.; Noon, Barry R.; Wiens, David; Ripple, William J.

    2016-01-01

    Recently, the barred owl (Strix varia) has expanded its range into the Pacific Northwest of the United States resulting in pronounced effects on the demography and behavior of the northern spotted owl (S. occidentalis caurina). The range expansion has brought together historically allopatric species, creating the potential for significant changes in the avian predator community with possible cascading effects on food-web dynamics. The adverse effects of the barred owl on the behavior and demography of the northern spotted owl are well-documented, but little is known about the immediate and long-term effects changes in the predator community may have on native species composition and ecosystem processes. Based on northern spotted owl and barred owl selection for diet and habitat resources, there is a potential for trophic cascades within the region's predator and prey communities, differing responses by their shared and unique prey species, and possible direct and indirect effects on ecosystem processes. We explored the possible ecological consequences of the barred owl range expansion to wildlife communities of the Pacific Northwest based on the theoretical underpinnings of predator–prey relationships, interspecific competition, intraguild predation, and potential cascading trophic interactions. Negative effects on fitness of northern spotted owls because of interspecific competition with barred owls are strong selection forces that may contribute to the regional extinction of the northern spotted owl. In addition, we posit that shared prey species and those uniquely consumed by barred owls, along with other competing native predators, may experience changes in behavior, abundance, and distribution as a result of increased rates of predation by rapidly expanding populations of barred owls.

  12. Evaluation on Biofilter in Recirculating Integrated Multi-Trophic Aquaculture

    Directory of Open Access Journals (Sweden)

    S. Sumoharjo

    2013-06-01

    Full Text Available Integrated multi-trophic aquaculture pays more attention as a bio-integrated food production system that serves as a model of sustainable aquaculture, minimizes waste discharge, increases diversity and yields multiple products. The objectives of this research were to analyze the efficiency of total ammonia nitrogen biofiltration and its effect on carrying capacity of fish rearing units. Pilot-scale bioreactor was designed with eight run-raceways (two meters of each that assembled in series. Race 1-3 were used to stock silky worm (Tubifex sp as detrivorous converter, then race 4-8 were used to plant three species of leaf-vegetable as photoautotrophic converters, i.e; spinach (Ipomoea reptana, green mustard (Brassica juncea and basil (Ocimum basilicum. The three plants were placed in randomized block design based on water flow direction. Mass balance of nutrient analysis, was applied to figure out the efficiency of bio-filtration and its effect on carrying capacity of rearing units. The result of the experiment showed that 86.5 % of total ammonia nitrogen removal was achieved in 32 days of culturing period. This efficiency able to support the carrying capacity of the fish tank up to 25.95 kg/lpm with maximum density was 62.69 kg/m3 of fish biomass productionDoi: http://dx.doi.org/10.12777/ijse.4.2.2013.80-85 [How to cite this article: Sumoharjo, S.  and Maidie, A. (2013. Evaluation on Biofilter in Recirculating Integrated Multi-Trophic Aquaculture.  International Journal of  Science and Engineering, 4(2,80-85. Doi: http://dx.doi.org/10.12777/ijse.4.2.2013.80-85

  13. Trophic relations of introduced flathead catfish in an atlantic river

    Science.gov (United States)

    Baumann, Jessica R.; Kwak, Thomas J.

    2011-01-01

    The flathead catfish Pylodictis olivaris is a large piscivore that is native to the Mississippi and Rio Grande river drainages but that has been widely introduced across the United States. River ecologists and fisheries managers are concerned about introduced flathead catfish populations because of the negative impacts on native fish communities or imperiled species associated with direct predation and indirect competition from this apex predator. We studied the trophic relations of introduced flathead catfish in an Atlantic river to further understand the effects on native fish communities. Crayfish (Astacidea) occurred most frequently in the flathead catfish diet, while sunfish Lepomis spp. comprised the greatest percentage by weight. Neither of two sympatric imperiled fish species (the federally endangered Cape Fear shiner Notropis mekistocholas and the Carolina redhorse Moxostoma sp., a federal species of concern) was found in any diet sample. An ontogenetic shift in diet was evident when flathead catfish reached about 300 mm, and length significantly explained the variation in the percent composition by weight of sunfish and darters Etheostoma and Percina spp. Flathead catfish showed positive prey selectivity for taxa that occupied similar benthic microhabitat, highlighting the importance of opportunistic feeding and prey encounter rates. Flathead catfish displayed a highly variable diel feeding chronology during July, when they had a mean stomach fullness of 0.32%, but then showed a single midday feeding peak during August (mean fullness = 0.52%). The gastric evacuation rate increased between July (0.40/h) and August (0.59/h), as did daily ration, which more than doubled between the 2 months (3.06% versus 7.37%). Our findings increase the understanding of introduced flathead catfish trophic relations and the degree of vulnerability among prey taxa, which resource managers may consider in fisheries management and conservation of native fish populations and

  14. Use of sequence data from rainbow trout and Atlantic salmon for SNP detection in Pacific salmon.

    Science.gov (United States)

    Smith, Christian T; Elfstrom, Carita M; Seeb, Lisa W; Seeb, James E

    2005-11-01

    Single nucleotide polymorphisms (SNPs) are a class of genetic markers that are well suited to a broad range of research and management applications. Although advances in genotyping chemistries and analysis methods continue to increase the potential advantages of using SNPs to address molecular ecological questions, the scarcity of available DNA sequence data for most species has limited marker development. As the number and diversity of species being targeted for large-scale sequencing has increased, so has the potential for using sequence from sister taxa for marker development in species of interest. We evaluated the use of Oncorhynchus mykiss and Salmo salar sequence data to identify SNPs in three other species (Oncorhynchus tshawytscha, Oncorhynchus nerka and Oncorhynchus keta). Primers designed based on O. mykiss and S. salar alignments were more successful than primers designed based on Oncorhynchus-only alignments for sequencing target species, presumably due to the much larger number of potential targets available from the former alignments and possibly greater sequence conservation in those targets. In sequencing approximately 89 kb we observed a frequency of 4.30 x 10(-3) SNPs per base pair. Approximately half (53/101) of the subsequently designed validation assays resulted in high-throughput SNP genotyping markers. We speculate that this relatively low conversion rate may reflect the duplicated nature of the salmon genome. Our results suggest that a large number of SNPs could be developed for Pacific salmon using sequence data from other species. While the costs of DNA sequencing are still significant, these must be compared to the costs of using other marker classes for a given application.

  15. Trophic factors as modulators of motor neuron physiology and survival: implications for ALS therapy

    Directory of Open Access Journals (Sweden)

    Luis B Tovar-y-Romo

    2014-02-01

    Full Text Available Motor neuron physiology and development depend on a continuous and tightly regulated trophic support from a variety of cellular sources. Trophic factors guide the generation and positioning of motor neurons during every stage of the developmental process. As well, they are involved in axon guidance and synapse formation. Even in the adult spinal cord an uninterrupted trophic input is required to maintain neuronal functioning and protection from noxious stimuli. Among the trophic factors that have been demonstrated to participate in motor neuron physiology are vascular endothelial growth factor (VEGF, glial-derived neurotrophic factor (GDNF, ciliary neurotrophic factor (CNTF and insulin-like growth factor 1 (IGF-1. Upon binding to membrane receptors expressed in motor neurons or neighboring glia, these trophic factors activate intracellular signaling pathways that promote cell survival and have protective action on motor neurons, in both in vivo and in vitro models of neuronal degeneration. For these reasons these factors have been considered a promising therapeutic method for amyotrophic lateral sclerosis (ALS and other neurodegenerative diseases, although their efficacy in human clinical trials have not yet shown the expected protection. In this review we summarize experimental data on the role of these trophic factors in motor neuron function and survival, as well as their mechanisms of action. We also briefly discuss the potential therapeutic use of the trophic factors and why these therapies may have not been yet successful in the clinical use.

  16. Trophic state index of a lake system using IRS (P6-LISS III) satellite imagery.

    Science.gov (United States)

    Sheela, A M; Letha, J; Joseph, Sabu; Ramachandran, K K; Sanalkumar, S P

    2011-06-01

    Water pollution has now become a major threat to the existence of living beings and water quality monitoring is an effective step towards the restoration of water quality. Lakes are versatile ecosystems and their eutrophication is a serious problem. Carlson Trophic State Index (CTSI) provides an insight into the trophic condition of a lake. CTSI has been modified for the study area and is used in this study. Satellite imagery analysis now plays a prominent role in the quick assessment of water quality in a vast area. This study is an attempt to assess the trophic state index based on secchi disk depth and chlorophyll a of a lake system (Akkulam-Veli lake, Kerala, India) using Indian Remote Sensing (IRS) P6 LISS III imagery. Field data were collected on the date of the overpass of the satellite. Multiple regression equation is found to yield superior results than the simple regression equations using spectral ratios and radiance from the individual bands, for the prediction of trophic state index from satellite imagery. The trophic state index based on secchi disk depth, derived from the satellite imagery, provides an accurate prediction of the trophic status of the lake. IRS P6-LISS III imagery can be effectively used for the assessment of the trophic condition of a lake system.

  17. Fish trophic structure in estuaries, with particular emphasis on estuarine typology and zoogeography.

    Science.gov (United States)

    Harrison, T D; Whitfield, A K

    2012-11-01

    A comparative analysis of the fish trophic structure was undertaken on some 190 South African estuaries spanning three zoogeographic regions and incorporating three broad estuarine types. Fish biomass trophic guild compositions and biomass trophic spectrum profiles were analysed using multivariate statistical techniques and included both inter-regional (zoogeographic) and intra-regional (estuarine typology) comparisons. Differences in the fish trophic structure of the various estuary types within each zoogeographic region were observed; these were linked to the relative biomass contribution of the various trophic guilds and also to differences in biomass trophic spectrum profiles of the fishes in each estuary type within each region. In spite of these differences in trophic structure, all estuaries were dominated by detritivores, which suggests that the main food source (detritus) is similar in all biogeographic regions. Preliminary indications are that a similar dependence by estuary-associated fishes on detritus food sources exists on a global basis but that detailed studies are required in order to confirm this assertion. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

  18. Okanogan Focus Watershed Salmon Creek : Annual Report 1999.

    Energy Technology Data Exchange (ETDEWEB)

    Lyman, Hilary

    1999-11-01

    During FY 1999 the Colville Tribes and the Okanogan Irrigation District (OID) agreed to study the feasibility of restoring and enhancing anadromous fish populations in Salmon Creek while maintaining the ability of the district to continue full water service delivery to it members.

  19. Salmon Aquaculture and Antimicrobial Resistance in the Marine Environment

    Science.gov (United States)

    Buschmann, Alejandro H.; Tomova, Alexandra; López, Alejandra; Maldonado, Miguel A.; Henríquez, Luis A.; Ivanova, Larisa; Moy, Fred; Godfrey, Henry P.; Cabello, Felipe C.

    2012-01-01

    Antimicrobials used in salmon aquaculture pass into the marine environment. This could have negative impacts on marine environmental biodiversity, and on terrestrial animal and human health as a result of selection for bacteria containing antimicrobial resistance genes. We therefore measured the numbers of culturable bacteria and antimicrobial-resistant bacteria in marine sediments in the Calbuco Archipelago, Chile, over 12-month period at a salmon aquaculture site approximately 20 m from a salmon farm and at a control site 8 km distant without observable aquaculture activities. Three antimicrobials extensively used in Chilean salmon aquaculture (oxytetracycline, oxolinic acid, and florfenicol) were studied. Although none of these antimicrobials was detected in sediments from either site, traces of flumequine, a fluoroquinolone antimicrobial also widely used in Chile, were present in sediments from both sites during this period. There were significant increases in bacterial numbers and antimicrobial-resistant fractions to oxytetracycline, oxolinic acid, and florfenicol in sediments from the aquaculture site compared to those from the control site. Interestingly, there were similar numbers of presumably plasmid-mediated resistance genes for oxytetracycline, oxolinic acid and florfenicol in unselected marine bacteria isolated from both aquaculture and control sites. These preliminary findings in one location may suggest that the current use of large amounts of antimicrobials in Chilean aquaculture has the potential to select for antimicrobial-resistant bacteria in marine sediments. PMID:22905164

  20. Salmon mortalities associated with a bloom of Alexandrium ...

    African Journals Online (AJOL)

    Blue mussels Mytilus edulis analysed from areas affected by the bloom reached levels of 18 000ìg STX equivalents 100g–1 of tissue. As a result of the salmon mortalities, a project was initiated to establish a monitoring approach for harmful algal blooms to provide an early warning of potential events and to act as a tool for ...

  1. Accounting for risk conflicts in Scottish salmon farming

    NARCIS (Netherlands)

    Georgakopoulos, G.; Thomson, I.; Kaldis, P.

    2008-01-01

    Purpose: To offer a theoretical analysis, inspired by contemporary research into risk, of the social and environmental accounting processes observed in an empirical study on Scottish salmon farming. Methodology / Approach: This paper used a Grounded Theory approach. Empirical evidence was collected

  2. Stream temperature variability: why it matters to salmon

    Science.gov (United States)

    E. Ashley Steel; Brian Beckman; Marie. Oliver

    2014-01-01

    Salmon evolved in natural river systems, where temperatures fluctuate daily, weekly, seasonally, and all along a stream’s path—from the mountains to the sea. Climate change and human activities alter this natural variability. Dams, for example, tend to reduce thermal fluctuations.Currently, scientists gauge habitat suitability for aquatic species by...

  3. Adaptive potential of a Pacific salmon challenged by climate change

    Science.gov (United States)

    Muñoz, Nicolas J.; Farrell, Anthony P.; Heath, John W.; Neff, Bryan D.

    2015-02-01

    Pacific salmon provide critical sustenance for millions of people worldwide and have far-reaching impacts on the productivity of ecosystems. Rising temperatures now threaten the persistence of these important fishes, yet it remains unknown whether populations can adapt. Here, we provide the first evidence that a Pacific salmon has both physiological and genetic capacities to increase its thermal tolerance in response to rising temperatures. In juvenile chinook salmon (Oncorhynchus tshawytscha), a 4 °C increase in developmental temperature was associated with a 2 °C increase in key measures of the thermal performance of cardiac function. Moreover, additive genetic effects significantly influenced several measures of cardiac capacity, indicative of heritable variation on which selection can act. However, a lack of both plasticity and genetic variation was found for the arrhythmic temperature of the heart, constraining this upper thermal limit to a maximum of 24.5 +/- 2.2 °C. Linking this constraint on thermal tolerance with present-day river temperatures and projected warming scenarios, we predict a 17% chance of catastrophic loss in the population by 2100 based on the average warming projection, with this chance increasing to 98% in the maximum warming scenario. Climate change mitigation is thus necessary to ensure the future viability of Pacific salmon populations.

  4. FACTS, FANTASIES, AND FORECASTS: THE FUTURE OF WILD PACIFIC SALMON

    Science.gov (United States)

    Throughout the far western contiguous United States (California, Oregon, Washington, and Idaho), many wild salmon stocks have declined and some have disappeared. The decline has taken place over the past 150 years, but there have been decades when the numbers increased. Overall...

  5. Economics of wild salmon ecosystems: Bristol Bay, Alaska

    Science.gov (United States)

    John W. Duffield; Christopher J. Neher; David A. Patterson; Oliver S. Goldsmith

    2007-01-01

    This paper provides an estimate of the economic value of wild salmon ecosystems in the major watershed of Bristol Bay, Alaska. The analysis utilizes both regional economic and social benefit-cost accounting frameworks. Key sectors analyzed include subsistence, commercial fishing, sport fishing, hunting, and nonconsumptive wildlife viewing and tourism. The mixed cash-...

  6. Effects of salmon calcitonin and calcitonin gene related peptide ...

    African Journals Online (AJOL)

    The aim of this investigation was to examine and compare the effects of calcitonin gene related peptide (CGRP) and salmon calcitonin (sCT) on gastric lesions and mucosal barrier components such as mucus and phospholipids in rats exposed to cold + restraint stress (CRS). Twenty-eight Wistar albino rats (150 – 200 g) ...

  7. 75 FR 14135 - Pacific Coastal Salmon Recovery Fund

    Science.gov (United States)

    2010-03-24

    ... productive results. Successful program and project proposals will include: a. A description of how the...- recognized tribes of the Columbia River and Pacific Coast for projects necessary for conservation of salmon... projects from individual eligible Indian tribes, eligible States, and representative Tribal commissions so...

  8. Salmon aquaculture and antimicrobial resistance in the marine environment.

    Directory of Open Access Journals (Sweden)

    Alejandro H Buschmann

    Full Text Available Antimicrobials used in salmon aquaculture pass into the marine environment. This could have negative impacts on marine environmental biodiversity, and on terrestrial animal and human health as a result of selection for bacteria containing antimicrobial resistance genes. We therefore measured the numbers of culturable bacteria and antimicrobial-resistant bacteria in marine sediments in the Calbuco Archipelago, Chile, over 12-month period at a salmon aquaculture site approximately 20 m from a salmon farm and at a control site 8 km distant without observable aquaculture activities. Three antimicrobials extensively used in Chilean salmon aquaculture (oxytetracycline, oxolinic acid, and florfenicol were studied. Although none of these antimicrobials was detected in sediments from either site, traces of flumequine, a fluoroquinolone antimicrobial also widely used in Chile, were present in sediments from both sites during this period. There were significant increases in bacterial numbers and antimicrobial-resistant fractions to oxytetracycline, oxolinic acid, and florfenicol in sediments from the aquaculture site compared to those from the control site. Interestingly, there were similar numbers of presumably plasmid-mediated resistance genes for oxytetracycline, oxolinic acid and florfenicol in unselected marine bacteria isolated from both aquaculture and control sites. These preliminary findings in one location may suggest that the current use of large amounts of antimicrobials in Chilean aquaculture has the potential to select for antimicrobial-resistant bacteria in marine sediments.

  9. Salmon River Habitat Enhancement, Part 1, 1984 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Konopacky, Richard C.

    1985-06-01

    This volume contains reports on subprojects involving the determining of alternatives to enhance salmonid habitat on patented land in Bear Valley Creek, Idaho, coordination activities for habitat projects occurring on streams within fishing areas of the Shoshone-Bannock Indian Tribes, and habitat and fish inventories in the Salmon River. Separate abstracts have been prepared for individual reports. (ACR)

  10. Humpback whales feed on hatchery-released juvenile salmon.

    Science.gov (United States)

    Chenoweth, Ellen M; Straley, Janice M; McPhee, Megan V; Atkinson, Shannon; Reifenstuhl, Steve

    2017-07-01

    Humpback whales are remarkable for the behavioural plasticity of their feeding tactics and the diversity of their diets. Within the last decade at hatchery release sites in Southeast Alaska, humpback whales have begun exploiting juvenile salmon, a previously undocumented prey. The anthropogenic source of these salmon and their important contribution to local fisheries makes the emergence of humpback whale predation a concern for the Southeast Alaska economy. Here, we describe the frequency of observing humpback whales, examine the role of temporal and spatial variables affecting the probability of sighting humpback whales and describe prey capture behaviours at five hatchery release sites. We coordinated twice-daily 15 min observations during the spring release seasons 2010-2015. Using logistic regression, we determined that the probability of occurrence of humpback whales increased after releases began and decreased after releases concluded. The probability of whale occurrence varied among release sites but did not increase significantly over the 6 year study period. Whales were reported to be feeding on juvenile chum, Chinook and coho salmon, with photographic and video records of whales feeding on coho salmon. The ability to adapt to new prey sources may be key to sustaining their population in a changing ocean.

  11. Disease Risk and Market Structure in Salmon Aquaculture

    NARCIS (Netherlands)

    Fischer, C.; Guttormsen, Atle; Smith, Martin

    2017-01-01

    We develop a model of a multi-national firm producing commodities for a global market in multiple locations with location-specific risks and different regulatory standards. Salmon aquaculture and disease outbreaks provide an empirically relevant example. We specifically examine details of the

  12. Navigating benefit transfer for salmon improvements in the Western US

    Directory of Open Access Journals (Sweden)

    Matthew August Weber

    2015-10-01

    Full Text Available A perennial problem in environmental resource management is targeting an efficient level of resource provision that maximizes societal well-being. Such management requires knowledge of both costs and benefits associated with varying management options. This paper illustrates the challenge of estimating the benefits of an improvement in a marine resource when secondary data must be used, and when total economic benefits include non-use values. An example of non-use values is existence value, which is not contingent on resource extraction nor recreational activities. State of the art techniques for adapting secondary data, or benefit transfer, are reviewed in the context of increasing anadromous salmon for an example Western US policy scenario. An extensive summary of applicable primary studies is provided, compiling observations from several studies surveying several thousand Western US households. The studies consistently indicate a high willingness to pay for increased salmon abundance. Analytical techniques for transferring data are described, with calculation examples using published tools, focusing on meta-regression and structural benefit transfer. While these advanced benefit transfer tools offer perspective on benefits beyond what can be learned by relying on a single study, they also represent a variety of challenges limiting their usefulness. While transparently navigating these issues, a monetized estimate of increased salmon for the policy case is provided, along with discussion on interpreting benefit transfer techniques and their results more generally. From this synthesis, several suggestions are also made for future primary salmon valuation studies.

  13. Intersexual trophic niche partitioning in an ant-eating spider (Araneae: Zodariidae.

    Directory of Open Access Journals (Sweden)

    Stano Pekár

    Full Text Available BACKGROUND: Divergence in trophic niche between the sexes may function to reduce competition between the sexes ("intersexual niche partitioning hypothesis", or may be result from differential selection among the sexes on maximizing reproductive output ("sexual selection hypothesis". The latter may lead to higher energy demands in females driven by fecundity selection, while males invest in mate searching. We tested predictions of the two hypotheses underlying intersexual trophic niche partitioning in a natural population of spiders. Zodarion jozefienae spiders specialize on Messor barbarus ants that are polymorphic in body size and hence comprise potential trophic niches for the spider, making this system well-suited to study intersexual trophic niche partitioning. METHODOLOGY/PRINCIPAL FINDINGS: Comparative analysis of trophic morphology (the chelicerae and body size of males, females and juveniles demonstrated highly female biased SSD (Sexual Size Dimorphism in body size, body weight, and in the size of chelicerae, the latter arising from sex-specific growth patterns in trophic morphology. In the field, female spiders actively selected ant sub-castes that were larger than the average prey size, and larger than ants captured by juveniles and males. Female fecundity was highly positively correlated with female body mass, which reflects foraging success during the adult stage. Females in laboratory experiments preferred the large ant sub-castes and displayed higher capture efficiency. In contrast, males occupied a different trophic niche and showed reduced foraging effort and reduced prey capture and feeding efficiency compared with females and juveniles. CONCLUSIONS/SIGNIFICANCE: Our data indicate that female-biased dimorphism in trophic morphology and body size correlate with sex-specific reproductive strategies. We propose that intersexual trophic niche partitioning is shaped primarily by fecundity selection in females, and results from sex

  14. Intersexual trophic niche partitioning in an ant-eating spider (Araneae: Zodariidae).

    Science.gov (United States)

    Pekár, Stano; Martišová, Martina; Bilde, Trine

    2011-01-27

    Divergence in trophic niche between the sexes may function to reduce competition between the sexes ("intersexual niche partitioning hypothesis"), or may be result from differential selection among the sexes on maximizing reproductive output ("sexual selection hypothesis"). The latter may lead to higher energy demands in females driven by fecundity selection, while males invest in mate searching. We tested predictions of the two hypotheses underlying intersexual trophic niche partitioning in a natural population of spiders. Zodarion jozefienae spiders specialize on Messor barbarus ants that are polymorphic in body size and hence comprise potential trophic niches for the spider, making this system well-suited to study intersexual trophic niche partitioning. Comparative analysis of trophic morphology (the chelicerae) and body size of males, females and juveniles demonstrated highly female biased SSD (Sexual Size Dimorphism) in body size, body weight, and in the size of chelicerae, the latter arising from sex-specific growth patterns in trophic morphology. In the field, female spiders actively selected ant sub-castes that were larger than the average prey size, and larger than ants captured by juveniles and males. Female fecundity was highly positively correlated with female body mass, which reflects foraging success during the adult stage. Females in laboratory experiments preferred the large ant sub-castes and displayed higher capture efficiency. In contrast, males occupied a different trophic niche and showed reduced foraging effort and reduced prey capture and feeding efficiency compared with females and juveniles. Our data indicate that female-biased dimorphism in trophic morphology and body size correlate with sex-specific reproductive strategies. We propose that intersexual trophic niche partitioning is shaped primarily by fecundity selection in females, and results from sex-differences in the route to successful reproduction where females are selected to

  15. Managing Pacific salmon escapements: The gaps between theory and reality

    Science.gov (United States)

    Knudsen, E. Eric; Knudsen, E. Eric; Steward, Cleveland R.; MacDonald, Donald D.; Williams, Jack E.; Reiser, Dudley W.

    1999-01-01

    There are myriad challenges to estimating intrinsic production capacity for Pacific salmon populations that are heavily exploited and/or suffering from habitat alteration. Likewise, it is difficult to determine whether perceived decreases in production are due to harvest, habitat, or hatchery influences, natural variation, or some combination of all four. There are dramatic gaps between the true nature of the salmon spawner/recruit relationship and the theoretical basis for describing and understanding the relationship. Importantly, there are also extensive practical difficulties associated with gathering and interpreting accurate escapement and run-size information and applying it to population management. Paradoxically, certain aspects of salmon management may well be contributing to losses in abundance and biodiversity, including harvesting salmon in mixed population fisheries, grouping populations into management units subject to a common harvest rate, and fully exploiting all available hatchery fish at the expense of wild fish escapements. Information on U.S. Pacific salmon escapement goal-setting methods, escapement data collection methods and estimation types, and the degree to which stocks are subjected to mixed stock fisheries was summarized and categorized for 1,025 known management units consisting of 9,430 known populations. Using criteria developed in this study, only 1% of U.S. escapement goals are by methods rated as excellent. Escapement goals for 16% of management units were rated as good. Over 60% of escapement goals have been set by methods rated as either fair or poor and 22% of management units have no escapement goals at all. Of the 9,430 populations for which any information was available, 6,614 (70%) had sufficient information to categorize the method by which escapement data are collected. Of those, data collection methods were rated as excellent for 1%, good for 1%, fair for 2%, and poor for 52%. Escapement estimates are not made for 44

  16. Physiological mechanism of homing migration in Pacific salmon from behavioral to molecular biological approaches.

    Science.gov (United States)

    Ueda, Hiroshi

    2011-01-15

    The amazing abilities of Pacific salmon to migrate long distances from the ocean to their natal streams for spawning have been investigated intensively since 1950's, but there are still many mysteries because of difficulties to follow their whole life cycle and to wait their sole reproductive timing for several years. In my laboratory, we have tried to clarify physiological mechanisms of homing migration in Pacific salmon, using four anadromous Pacific salmon (pink, Oncorhynchus gorbuscha; chum, Oncorhynchus keta; sockeye, Oncorhynchus nerka; masu, Oncorhynchus masou) in the north Pacific Ocean as well as two lacustrine salmon (sockeye and masu) in Lake Toya and Lake Shikotsu, Hokkaido, Japan, where the lakes serve as a model "ocean". Three different approaches from behavioral to molecular biological researches have been conducted using these model fish. First, the homing behaviors of adult chum salmon from the Bering Sea to Hokkaido as well as lacustrine sockeye and masu salmon in Lake Toya were examined by means of physiological biotelemetry techniques, and revealed that salmon can navigate in open water using different sensory systems. Second, the hormone profiles in the brain-pituitary-gonadal (BPG) axis were investigated in chum salmon and lacustrine sockeye salmon during their homing migration by means of hormone specific time-resolved fluoroimmunoassay (TR-FIA) systems, and clarified that salmon gonadotropin-releasing hormone (sGnRH) plays leading roles on homing migration. Third, the olfactory functions of salmon were studied by means of electrophysiological, behavioral, and molecular biological techniques, and made clear that olfactory discriminating ability of natal stream odors. These results have discussed with the evolutional aspects of four Pacific salmon, sexual differences in homing profiles, and the possibility of dissolved free amino acids (DFAA) as natal stream odors for salmon. Copyright © 2010 Elsevier Inc. All rights reserved.

  17. Disrupting the habit of interviewing

    Directory of Open Access Journals (Sweden)

    Eileen Honan

    2014-06-01

    Full Text Available This paper contributes to the growing domain of ‘post-qualitative’ research and experiments with a new (representational form to move away from traditional and clichéd descriptions of research methods. In this paper, I want to interrogate the category of interview, and the habit of interviewing, to disrupt the clichés, so as to allow thinking of different ways of writing/speaking/representing the interactions between researcher and researched that will breathe new life into qualitative inquiries. I will attempt to flatten and shred, destabilise and disrupt our common-sense ideas about interview, including those held most sacred to the qualitative community, that of anonymity and confidentiality, as well as the privilege of the ‘transcript’ in re-presenting interview data.

  18. Disruptive technologies and transportation : final report.

    Science.gov (United States)

    2016-06-01

    Disruptive technologies refer to innovations that, at first, may be considered unproven, lacking refinement, relatively unknown, or even impractical, but ultimately they supplant existing technologies and/or applications. In general, disruptive techn...

  19. Disrupting reconsolidation: pharmacological and behavioral manipulations

    NARCIS (Netherlands)

    Soeter, M.; Kindt, M.

    2011-01-01

    We previously demonstrated that disrupting reconsolidation by pharmacological manipulations "deleted" the emotional expression of a fear memory in humans. If we are to target reconsolidation in patients with anxiety disorders, the disruption of reconsolidation should produce content-limited

  20. Understanding disruptive behavior problems in preschool children.

    Science.gov (United States)

    Breitenstein, Susan M; Hill, Carri; Gross, Deborah

    2009-02-01

    Disruptive behavior problems in young children are the number one reason for referral to mental health agencies. However, owing to difficulties differentiating clinically significant disruptive behaviors from typical development, a significant proportion of young children with disruptive behavior problems go unidentified and untreated. Research supports the existence of disruptive behavior disorders in young children, and early identification and treatment are critical to interrupt the trajectory of early problems to more significant and impairing difficulties. The purposes of this article were to identify and discuss disruptive behavior problems in preschool children and to introduce readers to current definitions of disruptive behavior problems and emotion regulation. A review of risk factors and underlying emotion and behavior regulation difficulties implicated in the development of disruptive behavior problems is provided. Furthermore, clinical implications for nurses in the identification of disruptive behavior problems in preschool children for pediatric nurses are discussed.

  1. Disruptive technologies in higher education

    Directory of Open Access Journals (Sweden)

    Michael Flavin

    2012-08-01

    Full Text Available This paper analyses the role of “disruptive” innovative technologies in higher education. In this country and elsewhere, Higher Education Institutions (HEIs have invested significant sums in learning technologies, with Virtual Learning Environments (VLEs being more or less universal, but these technologies have not been universally adopted and used by students and staff. Instead, other technologies not owned or controlled by HEIs are widely used to support learning and teaching. According to Christensen's theory of Disruptive Innovation, these disruptive technologies are not designed explicitly to support learning and teaching in higher education, but have educational potential. This study uses Activity Theory and Expansive Learning to analyse data regarding the impact of disruptive technologies. The data were obtained through a questionnaire survey about awareness and use of technologies, and through observation and interviews, exploring participants’ actual practice. The survey answers tended to endorse Disruptive Innovation theory, with participants establishing meanings for technologies through their use of them, rather than in keeping with a designer's intentions. Observation revealed that learners use a narrow range of technologies to support learning, but with a tendency to use resources other than those supplied by their HEIs. Interviews showed that participants use simple and convenient technologies to support their learning and teaching. This study identifies a contradiction between learning technologies made available by HEIs, and technologies used in practice. There is no evidence to suggest that a wide range of technologies is being used to support learning and teaching. Instead, a small range of technologies is being used for a wide range of tasks. Students and lecturers are not dependent on their HEIs to support learning and teaching. Instead, they self-select technologies, with use weighted towards established brands. The

  2. Disrupted Nighttime Sleep in Narcolepsy

    Science.gov (United States)

    Roth, Thomas; Dauvilliers, Yves; Mignot, Emmanuel; Montplaisir, Jacques; Paul, Josh; Swick, Todd; Zee, Phyllis

    2013-01-01

    Study Objectives: Characterize disrupted nighttime sleep (DNS) in narcolepsy, an important symptom of narcolepsy. Methods: A panel of international narcolepsy experts was convened in 2011 to build a consensus characterization of DNS in patients with narcolepsy. A literature search of the Medline (1965 to date), Medline In-Process (latest weeks), Embase (1974 to date), Embase Alert (latest 8 weeks), and Biosis (1965 to date) databases was conducted using the following search terms: narcolepsy and disrupted nighttime sleep, disturbed nighttime sleep, fragmented sleep, consolidated sleep, sleep disruption, and narcolepsy questionnaire. The purpose of the literature search was to identify publications characterizing the nighttime sleep of patients with narcolepsy. The panel reviewed the literature. Nocturnal sleep can also be disturbed by REM sleep abnormalities such as vivid dreaming and REM sleep behavior disorder; however, these were not reviewed in the current paper, as we were evaluating for idiopathic sleep disturbances. Results: The literature reviewed provide a consistent characterization of nighttime sleep in patients with narcolepsy as fragmented, with reports of frequent, brief nightly awakenings with difficulties returning to sleep and associated reports of poor sleep quality. Polysomnographic studies consistently report frequent awakenings/arousals after sleep onset, more stage 1 (S1) sleep, and more frequent shifts to S1 sleep or wake from deeper stages of sleep. The consensus of the International Experts' Panel on Narcolepsy was that DNS can be distressing for patients with narcolepsy and that treatment of DNS warrants consideration. Conclusions: Clinicians involved in the management of patients with narcolepsy should investigate patients' quality of nighttime sleep, give weight and consideration to patient reports of nighttime sleep experience, and consider DNS a target for treatment. Citation: Roth T; Dauvilliers Y; Mignot E; Montplaisir J; Paul J

  3. [Applications of stable isotope analysis in the trophic ecology studies of cephalopods].

    Science.gov (United States)

    Li, Yun-Kai; Gong, Yi; Chen, Xin-Jun

    2014-05-01

    Cephalopods play an important role in marine food webs, however, knowledge about their complex life history, especially their feeding ecology, remains limited. With the rapidly increasing use of stable isotope analysis (SIA) in ecology, it becomes a powerful tool and complement of traditional methods for investigating the trophic ecology and migration patterns of invertebrates. Here, after summarizing the current methods for trophic ecology investigation of cephalopods, applications of SIA in studying the trophic ecology of cephalopods were reviewed, including the key issues such as standardization of available tissues for SIA analyzing, diet shift and migration patterns of cephalopods, with the aim of advancing its application in the biology of cephalopods in the future.

  4. Wolves trigger a trophic cascade to berries as alternative food for grizzly bears.

    Science.gov (United States)

    Ripple, William J; Beschta, Robert L; Fortin, Jennifer K; Robbins, Charles T

    2015-05-01

    This is a Forum article in response to: Barber-Meyer, S. (2015) Trophic cascades from wolves to grizzly bears or changing abundance of bears and alternate foods? Journal of Animal Ecology, 83, doi: 10.1111/1365-2656.12338. We used multiple data sets and study areas as well as several lines of evidence to investigate potential trophic linkages in Yellowstone National Park. Our results suggest that a trophic cascade from wolves to elk to berry production to berry consumption by grizzly bears may now be underway in the Park. © 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.

  5. Adaptive behaviour, tri-trophic food-web stability and damping of chaos

    OpenAIRE

    Visser, André W.; Mariani, Patrizio; Pigolotti, Simone

    2011-01-01

    We examine the effect of adaptive foraging behaviour within a tri-trophic food web with intra-guild predation. The intra-guild prey is allowed to adjust its foraging effort so as to achieve an optimal per capita growth rate in the face of realized feeding, predation risk and foraging cost. Adaptive fitness-seeking behaviour of the intra-guild prey has a stabilizing effect on the tri-trophic food-web dynamics provided that (i) a finite optimal foraging effort exists and (ii) the trophic transf...

  6. Diets and trophic guilds of small fishes from coastal marine habitats in western Taiwan.

    Science.gov (United States)

    Egan, J P; Chew, U-S; Kuo, C-H; Villarroel-Diaz, V; Hundt, P J; Iwinski, N G; Hammer, M P; Simons, A M

    2017-07-01

    The diets and trophic guilds of small fishes were examined along marine sandy beaches and in estuaries at depths trophic guilds were identified. The zooplanktivore guild contained the most fish species. Maximum prey size consumption was positively correlated with standard length (LS ) in seven species and at the assemblage level and negatively correlated with LS in a single detritivorous species. The diet data and trophic guild scheme produced by this study contribute to an understanding of coastal marine food webs and can inform ecosystem-based fisheries management. © 2017 The Fisheries Society of the British Isles.

  7. Atlantic salmon reovirus infection causes a CD8 T cell myocarditis in Atlantic salmon (Salmo salar L..

    Directory of Open Access Journals (Sweden)

    Aase B Mikalsen

    Full Text Available Heart and skeletal inflammation (HSMI of farmed Atlantic salmon (Salmo salar L. is a disease characterized by a chronic myocarditis involving the epicardium and the compact and spongious part of the heart ventricle. Chronic myositis of the red skeletal muscle is also a typical finding of HSMI. Piscine reovirus (PRV has been detected by real-time PCR from farmed and wild salmon with and without typical changes of HSMI and thus the causal relationship between presence of virus and the disease has not been fully determined. In this study we show that the Atlantic salmon reovirus (ASRV, identical to PRV, can be passaged in GF-1 cells and experimental challenge of naïve Atlantic salmon with cell culture passaged reovirus results in cardiac and skeletal muscle pathology typical of HSMI with onset of pathology from 6 weeks, peaking by 9 weeks post challenge. ASRV replicates in heart tissue and the peak level of virus replication coincides with peak of heart lesions. We further demonstrate mRNA transcript assessment and in situ characterization that challenged fish develop a CD8+ T cell myocarditis.

  8. Physical and nutritional properties of baby food containing added red salmon oil (Oncorhynchus nerka) and microencapsulated red salmon oil

    Science.gov (United States)

    Unpurified red salmon oil (UPSO) was purified (PSO) using chitosan. Both unpurified and purified oils were evaluated for peroxide value (PV), free fatty acids (FFA), fatty acid methyl esters (FAME), moisture, and color. An emulsion system containing PSO (EPSO) was prepared: system was analyzed for c...

  9. Using Phylogenetic Analysis to Detect Market Substitution of Atlantic Salmon for Pacific Salmon: An Introductory Biology Laboratory Experiment

    Science.gov (United States)

    Cline, Erica; Gogarten, Jennifer

    2012-01-01

    We describe a laboratory exercise developed for the cell and molecular biology quarter of a year-long majors' undergraduate introductory biology sequence. In an analysis of salmon samples collected by students in their local stores and restaurants, DNA sequencing and phylogenetic analysis were used to detect market substitution of Atlantic salmon…

  10. Dealing with Disruptive Behavior of Adult Learners

    Science.gov (United States)

    Dobmeier, Robert; Moran, Joseph

    2008-01-01

    The adult education literature on disruptive behavior of adult learners was reviewed and a survey on disruptive behavior of adult learners was conducted with adult educators. The findings are synthesized in a conceptual framework for understanding the types and causes of disruptive behavior, which fall into the categories of inattention,…

  11. Revision Hope: Writing Disruption in Composition Studies.

    Science.gov (United States)

    Jung, Julie

    1997-01-01

    Uses Roland Barthes's metaphor of the "punctum" to explore the transformative potential of disruptions. Argues that writing teachers have been trained to read disruption in texts and classrooms as "evidence of poor taste or failed pedagogy," but that disruptions delay closure and thereby create spaces wherein theories and…

  12. Disruptive innovation as an entrepreneurial process

    NARCIS (Netherlands)

    Chandra, Y.; Yang, S.-J.S.; Singh, P.; Prajogo, D.; O'Neill, P.; Rahman, S.

    2008-01-01

    Research on conditions and causal mechanisms that influence disruptive innovation has been relatively unexplored in the extant research in disruptive innovation. By re-conceptualizing disruptive innovation as an entrepreneurial process at product, firm and industry levels, this paper draws on

  13. The disruptive instability in Tokamak plasmas

    NARCIS (Netherlands)

    Salzedas, F.J.B.

    2000-01-01

    Studies performed in RTP (Rijnhuizen Tokamak Project) of the most violent and dangerous instability in tokamak plasmas, the major disruption, are presented. A particular class of disruptions is analyzed, namely the density limit disruption, which occur in high density plasmas. The radiative

  14. Fisheries-induced disruptive selection.

    Science.gov (United States)

    Landi, Pietro; Hui, Cang; Dieckmann, Ulf

    2015-01-21

    Commercial harvesting is recognized to induce adaptive responses of life-history traits in fish populations, in particular by shifting the age and size at maturation through directional selection. In addition to such evolution of a target stock, the corresponding fishery itself may adapt, in terms of fishing policy, technological progress, fleet dynamics, and adaptive harvest. The aim of this study is to assess how the interplay between natural and artificial selection, in the simplest setting in which a fishery and a target stock coevolve, can lead to disruptive selection, which in turn may cause trait diversification. To this end, we build an eco-evolutionary model for a size-structured population, in which both the stock׳s maturation schedule and the fishery׳s harvest rate are adaptive, while fishing may be subject to a selective policy based on fish size and/or maturity stage. Using numerical bifurcation analysis, we study how the potential for disruptive selection changes with fishing policy, fishing mortality, harvest specialization, life-history tradeoffs associated with early maturation, and other demographic and environmental parameters. We report the following findings. First, fisheries-induced disruptive selection is readily caused by commonly used fishing policies, and occurs even for policies that are not specific for fish size or maturity, provided that the harvest is sufficiently adaptive and large individuals are targeted intensively. Second, disruptive selection is more likely in stocks in which the selective pressure for early maturation is naturally strong, provided life-history tradeoffs are sufficiently consequential. Third, when a fish stock is overexploited, fisheries targeting only large individuals might slightly increase sustainable yield by causing trait diversification (even though the resultant yield always remains lower than the maximum sustainable yield that could be obtained under low fishing mortality, without causing disruptive

  15. Enhanced transcriptomic responses in the Pacific salmon louse Lepeophtheirus salmonis oncorhynchi to the non-native Atlantic Salmon Salmo salar suggests increased parasite fitness.

    Science.gov (United States)

    Braden, Laura M; Sutherland, Ben J G; Koop, Ben F; Jones, Simon R M

    2017-01-30

    Outcomes of infections with the salmon louse Lepeophtheirus salmonis vary considerably among its natural hosts (Salmo, Oncorhynchus spp.). Host-parasite interactions range from weak to strong host responses accompanied by high to low parasite abundances, respectively. Parasite behavioral studies indicate that the louse prefers the host Atlantic Salmon (Salmo salar), which is characterized by a weak immune response, and that this results in enhanced parasite reproduction and growth rates. Furthermore, parasite-derived immunosuppressive molecules (e.g., proteases) have been detected at higher amounts in response to the mucus of Atlantic Salmon relative to Coho Salmon (Oncorhynchus kisutch). However, the host-specific responses of the salmon louse have not been well characterized in either of the genetically distinct sub-species that occur in the Atlantic and Pacific Oceans. We assessed and compared the transcriptomic feeding response of the Pacific salmon louse (L. salmonis oncorhynchi,) while parasitizing the highly susceptible Atlantic Salmon and Sockeye Salmon (Oncorhynchus nerka) or the more resistant Coho Salmon (Oncorhynchus kisutch) using a 38 K oligonucleotide microarray. The response of the louse was enhanced both in the number of overexpressed genes and in the magnitude of expression while feeding on the non-native Atlantic Salmon, compared to either Coho or Sockeye Salmon. For example, putative virulence factors (e.g., cathepsin L, trypsin, carboxypeptidase B), metabolic enzymes (e.g., cytochrome B, cytochrome C), protein synthesis enzymes (e.g., ribosomal protein P2, 60S ribosomal protein L7), and reproduction-related genes (e.g., estrogen sulfotransferase) were overexpressed in Atlantic-fed lice, indicating heightened parasite fitness with this host species. In contrast, responses in Coho- or Sockeye-fed lice were more similar to those of parasites deprived of a host. To test for host acclimation by the parasite, we performed a reciprocal host transfer

  16. Effects of dam removal on Tule Fall Chinook salmon spawning habitat in the White Salmon River, Washington

    Science.gov (United States)

    Hatten, James R.; Batt, Thomas R.; Skalicky, Joseph J.; Engle, Rod; Barton, Gary J.; Fosness, Ryan L.; Warren, Joe

    2016-01-01

    Condit Dam is one of the largest hydroelectric dams ever removed in the USA. Breached in a single explosive event in October 2011, hundreds-of-thousands of cubic metres of sediment washed down the White Salmon River onto spawning grounds of a threatened species, Columbia River tule fall Chinook salmon Oncorhynchus tshawytscha. We investigated over a 3-year period (2010–2012) how dam breaching affected channel morphology, river hydraulics, sediment composition and tule fall Chinook salmon (hereafter ‘tule salmon’) spawning habitat in the lower 1.7 km of the White Salmon River (project area). As expected, dam breaching dramatically affected channel morphology and spawning habitat due to a large load of sediment released from Northwestern Lake. Forty-two per cent of the project area that was previously covered in water was converted into islands or new shoreline, while a large pool near the mouth filled with sediments and a delta formed at the mouth. A two-dimensional hydrodynamic model revealed that pool area decreased 68.7% in the project area, while glides and riffles increased 659% and 530%, respectively. A spatially explicit habitat model found the mean probability of spawning habitat increased 46.2% after dam breaching due to an increase in glides and riffles. Shifting channels and bank instability continue to negatively affect some spawning habitat as sediments continue to wash downstream from former Northwestern Lake, but 300 m of new spawning habitat (river kilometre 0.6 to 0.9) that formed immediately post-breach has persisted into 2015. Less than 10% of tule salmon have spawned upstream of the former dam site to date, but the run sizes appear healthy and stable. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

  17. Conservation and care: material politics and Atlantic salmon on Newfoundland’s Gander River

    Directory of Open Access Journals (Sweden)

    Jennifer Daniels

    2017-11-01

    Full Text Available Abstract This paper aims to contribute to an emerging and vibrant body of post-structural scholarship situated within science technology and society (STS on practices and their role in world making. Our focus is Atlantic salmon conservation in the Canadian province of Newfoundland and Labrador. We examine the different material and social orders that have over time connected human and salmon bodies. These different socio-material orders do not exist in harmony. On the contrary, they are in tension and reflect different visions/versions of how to conserve and care for Atlantic salmon. Our contribution is to interfere with the dominant narrative of Atlantic salmon conservation by drawing on the concept of care, and by introducing a new salmon that we call the willful salmon.

  18. Trophic state monitoring of lakes and reservoirs using remote sensing

    Science.gov (United States)

    Aten, Michelle L.

    Lakes and reservoirs are important resources that provide water for critical needs, such as drinking water, agriculture, recreation, fisheries, wildlife, and other uses. However, there is increasing concern that anthropogenic eutrophication threatens the usability of these natural resources. Therefore, this research investigates these complex hydrologic ecosystems and recommends a methodology for monitoring the trophic state of lakes and reservoirs using remote sensing data. The Mississippi Department of Environmental Quality provided in situ data for seven Mississippi lakes including, Arkabutla, Bay Springs, Enid, Grenada, Okatibbee, Ross Barnett, and Sardis lakes. This research explored the relationships between the Secchi depth (SD), chlorophyll-a (CHL), and total phosphorus (TP) in situ data and Moderate Resolution Imaging Spectroradiometer (MODIS) spectral reflectance data. This was accomplished by deriving Carlson Trophic State Index values for each in situ measurements and using these TSI(SD), TSI(CHL), and TSI(TP) values to evaluate potential predictive methods. Simple linear regression was performed to quantify the strength of the relationships between the in situ data and MODIS surface reflectance values. However, R-square values were too low and inconsistent to justify additional analyses. Therefore, machine learning models from the Waikato Environment for Knowledge Analysis (WEKA) software workbench were explored and tested. Optimal predictive models and settings were investigated for two meta-learner classifiers, three Bayesian classifiers and three decision tree classifiers. The Classification Via Regression yielded the best results when using large datasets, the all-but-one iteration setting, MODIS A1 individual bands as predictors, and TSI(SD) as targets. For this model and these settings, the percentages of correctly classified instances ranged from 77.74% to 81.98% and kappa values ranged from 0.41 to 0.48. The percentage of correctly classified

  19. Trophic ecology drives contaminant concentrations within a tropical seabird community.

    Science.gov (United States)

    Sebastiano, Manrico; Bustamante, Paco; Eulaers, Igor; Malarvannan, Govindan; Mendez-Fernandez, Paula; Churlaud, Carine; Blévin, Pierre; Hauselmann, Antoine; Covaci, Adrian; Eens, Marcel; Costantini, David; Chastel, Olivier

    2017-08-01

    To support environmental management programs, there is an urgent need to know about the presence and understand the dynamics of major contaminants in seabird communities of key marine ecosystems. In this study, we investigated the concentrations and trophodynamics of trace elements in six seabird species and persistent organic pollutants (POPs) in three seabird species breeding on Grand Connétable Island (French Guiana), an area where the increase in human population and mining activities has raised concerns in recent years. Red blood cell Hg concentrations in adults were the highest in Magnificent frigatebirds Fregata magnificens (median: 5.6 μg g -1 dw; range: 3.8-7.8 μg g -1 dw) and lowest in Sooty terns Onychoprion fuscatus (median: 0.9 μg g -1 dw; range: 0.6-1.1 μg g -1 dw). Among POPs, dichlorodiphenyldichloroethylene (p,p'-DDE) was the most abundant compound in plasma of Cayenne terns Thalasseus sandvicensis (median: 1100 pg g -1 ww; range: 160 ± 5100 pg g -1 ww), while polychlorinated biphenyls (PCBs) were the most abundant compound class in plasma of Magnificent frigatebirds (median: 640 pg g -1 ww; range 330 ± 2700 pg g -1 ww). While low intensity of POP exposure does not appear to pose a health threat to this seabird community, Hg concentration in several adults Laughing gulls Leucophaeus atricilla and Royal terns Thalasseus maximus, and in all Magnificent frigatebirds was similar or higher than that of high contaminated seabird populations. Furthermore, nestling red blood cells also contained Hg concentrations of concern, and further studies should investigate its potential health impact in this seabird community. Differences in adult trophic ecology of the six species explained interspecific variation in exposure to trace element and POPs, while nestling trophic ecology provides indications about the diverse feeding strategies adopted by the six species, with the consequent variation in exposure to contaminants. Copyright

  20. From Digital Disruption to Business Model Scalability

    DEFF Research Database (Denmark)

    Nielsen, Christian; Lund, Morten; Thomsen, Peter Poulsen

    2017-01-01

    as a response to digital disruption. A series of case studies illustrate that besides frequent existing messages in the business literature relating to the importance of creating agile businesses, both in growing and declining economies, as well as hard to copy value propositions or value propositions that take......This article discusses the terms disruption, digital disruption, business models and business model scalability. It illustrates how managers should be using these terms for the benefit of their business by developing business models capable of achieving exponentially increasing returns to scale...... will seldom lead to business model scalability capable of competing with digital disruption(s)....

  1. Unintended consequences of management actions in salt pond restoration: cascading effects in trophic interactions

    National Research Council Canada - National Science Library

    Takekawa, John Y; Ackerman, Joshua T; Brand, L Arriana; Graham, Tanya R; Eagles-Smith, Collin A; Herzog, Mark P; Topping, Brent R; Shellenbarger, Gregory G; Kuwabara, James S; Mruz, Eric; Piotter, Sara L; Athearn, Nicole D

    2015-01-01

    .... Here, we describe a case study of unexpected consequences of a low-dissolved oxygen (DO) event on trophic interactions in a salt pond system following management actions to reduce salinity concentrations...

  2. Unintended Consequences of Management Actions in Salt Pond Restoration: Cascading Effects in Trophic Interactions: e0119345

    National Research Council Canada - National Science Library

    John Y Takekawa; Joshua T Ackerman; L Arriana Brand; Tanya R Graham; Collin A Eagles-Smith; Mark P Herzog; Brent R Topping; Gregory G Shellenbarger; James S Kuwabara; Eric Mruz; Sara L Piotter; Nicole D Athearn

    2015-01-01

    .... Here, we describe a case study of unexpected consequences of a low-dissolved oxygen (DO) event on trophic interactions in a salt pond system following management actions to reduce salinity concentrations...

  3. Taxonomic and trophic-level differences in the climate sensitivity of seasonal events

    Science.gov (United States)

    Høye, T. T.; Thackeray, S.; Henrys, P. A.; Hemming, D.; Bell, J. R.; Botham, M. S.; Burthe, S.; Helaouet, P.; Johns, D.; Jones, I. D.; Leech, D. I.; Mackay, E. B.; Massimino, D.; Atkinson, S.; Bacon, P. J.; Brereton, T. M.; Carvalho, L.; Clutton-Brock, T. H.; Duck, C.; Edwards, M.; Elliott, J. M.; Hall, S.; Harrington, R.; Pearce-Higgins, J. W.; Kruuk, L. E.; Pemberton, J. M.; Sparks, T. H.; Thompson, P. M.; White, I.; Winfield, I. J.; Wanless, S.

    2015-12-01

    Among-species differences in phenological responses to climate change are of sufficient magnitude to desynchronise key ecological interactions, threatening ecosystem function and services. To assess these threats, it is vital to quantify the relative impact of climate change on species at different trophic levels. Here we apply a novel Climate Sensitivity Profile approach to 10,003 terrestrial and aquatic phenological data sets, spatially matched to temperature and precipitation data, quantifying among-species variation in climate sensitivity. The direction, magnitude and timing of climate sensitivity varied markedly among organisms sharing taxonomic affinities or trophic position. Despite this, we detected a systematic difference in the direction and magnitude, but not seasonal timing, of phenological climate sensitivity among trophic levels. Secondary consumers showed consistently lower climate sensitivity than other groups and are projected to lag behind phenological changes at lower trophic levels, potentially making them at higher risk of disconnection with seasonal resources.

  4. The winter feeding ecology and trophic relationships of marine birds in Kachemak Bay, Alaska [Draft

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The primary objectives of the study were; (1) to determine the kinds, amounts, and trophic levels of prey used by the main species of marine birds wintering on the...

  5. Trophic dynamics and fishery potentials of the Indian Occean - critical assessment

    Digital Repository Service at National Institute of Oceanography (India)

    Dalal, S.G.; Parulekar, A.H.

    of the basic estimates from primary production; zooplankton-biomass and production; benthic and microbial production and the commonly used conversion efficiency at different trophic levels in relation to complexities of tropical marine food chain...

  6. Intersexual Trophic Niche Partitioning in an Ant-Eating Spider (Araneae: Zodariidae)

    National Research Council Canada - National Science Library

    Pekar, Stano; Martisova, Martina; Bilde, Trine

    2011-01-01

    .... Zodarion jozefienae spiders specialize on Messor barbarus ants that are polymorphic in body size and hence comprise potential trophic niches for the spider, making this system well-suited to study...

  7. Trophic fluxes in a beach seine fishery of the Campeche Bank

    National Research Council Canada - National Science Library

    Vega-Cendejas, M.E; Arreguin-Sanches, F; Hernandez, M

    1990-01-01

    The principal trophic interactions that occur between various species from a beach seine fishery of the Campeche Bank were determined through the ECOPATH II model using stomach contents data and biomass estimates...

  8. Sources of trophic action on performance and intestinal morphometry of broiler chickens vaccinated against coccidiosis

    Directory of Open Access Journals (Sweden)

    MI Sakamoto

    2014-12-01

    Full Text Available The aim of this experiment was to evaluate the effect of sources of trophic action (glutamine alone, glutamine associated with glutamic acid and yeast associated with vaccination against coccidiosis on the performance and morphometry of the small intestine of broilers. In the trial, 1,200 broiler chicks were distributed according to a completely randomized design with a 3 x 2 + 2 (trophic action x vaccination or not + control - free trophic factor factorial arrangement, with five replicates of 30 birds each. Vaccination negatively affected performance parameters and the morphometry of the intestinal mucosa, but at the end of the experimental period, among the broilers vaccinated against coccidiosis, the group fed glutamine presented better recovery from epithelial losses of the intestinal mucosa compared with the control groups. Therefore, the dietary supplementation with the evaluated sources of trophic action could be a strategy to enhance the development of broilers submitted to vaccine stress, also considering the economic viability of the productive segment.

  9. Trophic Cascades Promote Threshold-Like Shifts in Pelagic Marine Ecosystems

    National Research Council Canada - National Science Library

    Michele Casini; Joakim Hjelm; Juan-Carlos Molinero; Johan Lövgren; Massimiliano Cardinale; Valerio Bartolino; Andrea Belgrano; Georgs Kornilovs; Robert T. Paine

    2009-01-01

    .... By using field data covering a 30-year period, we show for the Baltic Sea that the underlying mechanisms of trophic cascades produced a shift in ecosystem functioning after the collapse of the top predator cod...

  10. Foraging behaviour at the fourth trophic level: a comparative study of host location in aphid hyperparasitoids

    NARCIS (Netherlands)

    Buitenhuis, R.; Vet, L.E.M.; Boivin, G.; Brodeur, J.

    2005-01-01

    In studies of foraging behaviour in a multitrophic context, the fourth trophic level has generally been ignored. We used four aphid hyperparasitoid species: Dendrocerus carpenteri (Curtis) (Hymenoptera: Megaspilidae), Asaphes suspensus Walker (Hymenoptera: Pteromalidae), Alloxysta victrix (Westwood)

  11. Trophic roles of scavenger beetles in relation to decomposition stages and seasons

    Directory of Open Access Journals (Sweden)

    Noelia I. Zanetti

    2015-06-01

    Full Text Available Carcasses represent a trophic and reproductive resource or shelter for arthropods, which are a representative component of the decomposition process. Four experiments, one per season, were conducted in a semi-rural area of Bahía Blanca, Argentina, to study the trophic roles of cadaveric beetles, evaluating the abundance, composition and dominance during all decomposition stages and seasons. Species of necrophagous, necrophilous and omnivorous habits were found. Abundance, composition and dominance of beetles in relation to their trophic roles changed according to seasons and decomposition stages. Guilds and patterns of succession were established in relation to those periods. Trophic roles could be an indicator of beetle associations with decomposition stages and seasons.

  12. Trophic structure of the Barents Sea fish assemblage with special reference to the cod stock recoverability

    Science.gov (United States)

    Dolgov, Andrey V.

    2009-04-01

    The species composition and trophic structure of the Barents Sea fish assemblage is analysed based on data from research survey trawls and diet analyses of various species. Atlantic cod was the dominant fish species encountered, accounting for more than 55% by abundance or biomass. Only five fish species (long rough dab, thorny skate, Greenland halibut, deepwater redfish and saithe) were sufficiently abundant to be considered as possible food competitors with cod in the Barents Sea. However, possible trophic competition is not high, due to low spatial and temporal overlap between cod and these other species. Analyses of fish assemblages and trophic structures of the Barents Sea and other areas (North Sea, Western Greenland, Newfoundland-Labrador shelf) suggest that Barents Sea cod is the only cod stock for which the ability to recover may not be restricted by trophic relations among fishes, due to a lack of other abundant predatory species and low potential for competition caused by spatial-temporal changes.

  13. A trophic model of fringing coral reefs in Nanwan Bay, southern Taiwan suggests overfishing.

    Science.gov (United States)

    Liu, Pi-Jen; Shao, Kwang-Tsao; Jan, Rong-Quen; Fan, Tung-Yung; Wong, Saou-Lien; Hwang, Jiang-Shiou; Chen, Jen-Ping; Chen, Chung-Chi; Lin, Hsing-Juh

    2009-09-01

    Several coral reefs of Nanwan Bay, Taiwan have recently undergone shifts to macroalgal or sea anemone dominance. Thus, a mass-balance trophic model was constructed to analyze the structure and functioning of the food web. The fringing reef model was comprised of 18 compartments, with the highest trophic level of 3.45 for piscivorous fish. Comparative analyses with other reef models demonstrated that Nanwan Bay was similar to reefs with high fishery catches. While coral biomass was not lower, fish biomass was lower than those of reefs with high catches. Consequently, the sums of consumption and respiratory flows and total system throughput were also decreased. The Nanwan Bay model potentially suggests an overfished status in which the mean trophic level of the catch, matter cycling, and trophic transfer efficiency are extremely reduced.

  14. Adaptive behaviour, tri-trophic food-web stability and damping of chaos

    DEFF Research Database (Denmark)

    Visser, Andre; Mariani, Patrizio; Pigolotti, Simone

    2012-01-01

    We examine the effect of adaptive foraging behaviour within a tri-trophic food web with intra-guild predation. The intra-guild prey is allowed to adjust its foraging effort so as to achieve an optimal per capita growth rate in the face of realized feeding, predation risk and foraging cost. Adaptive...... fitness-seeking behaviour of the intra-guild prey has a stabilizing effect on the tri-trophic food-web dynamics provided that (i) a finite optimal foraging effort exists and (ii) the trophic transfer efficiency from resource to predator via the intra-guild prey is greater than that from the resource...... directly. The latter condition is a general criterion for the feasibility of intra-guild predation as a trophic mode. Under these conditions, we demonstrate rigorously that adaptive behaviour will always promote stability of community dynamics in the sense that the region of parameter space in which...

  15. Attractiveness of native mammal's feces of different trophic guilds to dung beetles (Coleoptera: Scarabaeinae)

    National Research Council Canada - National Science Library

    Bogoni, Juliano A; Hernández, Malva I M

    2014-01-01

    ...) types varies depending on mammal trophic guild and associated nutritional content. This study was conducted in Atlantic Forest fragments in the Parque Estadual da Serra do Tabuleiro, Santa Catarina, Brazil...

  16. Unpacking brown food‐webs: Animal trophic identity reflects rampant microbivory

    National Research Council Canada - National Science Library

    Steffan, Shawn A; Chikaraishi, Yoshito; Dharampal, Prarthana S; Pauli, Jonathan N; Guédot, Christelle; Ohkouchi, Naohiko

    2017-01-01

    ...”) food webs has remained unresolved. Measurement of detritivore trophic position is complicated by the fact that detritus is suffused with microbes, creating a detrital complex of living and nonliving biomass...

  17. Disease resistance is related to inherent swimming performance in Atlantic salmon.

    OpenAIRE

    Castro Vicente; Grisdale-Helland Barbara; Jørgensen Sven M; Helgerud Jan; Claireaux Guy; Farrell Anthony P; Krasnov Aleksei; Helland Ståle J; Takle Harald

    2013-01-01

    Abstract Background Like humans, fish can be classified according to their athletic performance. Sustained exercise training of fish can improve growth and physical capacity, and recent results have documented improved disease resistance in exercised Atlantic salmon. In this study we investigated the effects of inherent swimming performance and exercise training on disease resistance in Atlantic salmon. Atlantic salmon were first classified as either poor or good according to their swimming p...

  18. Genetic Analysis of a Population of Atlantic salmon (Salmo salar, L.)in the Rhine System

    OpenAIRE

    Papa, Laura

    2009-01-01

    The present study was developed under the guidelines of a regional project to support the management of the anadromous salmonids in the Rhine, particularly the reintroduction of the Atlantic salmon (Salmo salar, L.) The main aim was to assign the salmons ascending to the Iffezheim lock to salmons used for reintroduction in the Rhine. It was analysed if such an assignment was reasonably possible. Furthermore, we wanted to find out if an established Rhine population already exists. The Ph.D. st...

  19. Maintenance of Genetic Diversity in Natural Spawning of Captively-Reared Endangered Sockeye Salmon, Oncorhynchus nerka

    OpenAIRE

    Withler, Ruth E.; David S. O'Brien; Nicolette M. Watson; K. Janine Supernault

    2014-01-01

    Captive propagation of Pacific salmon is routine, but few captive breeding programs have been conducted to successfully re-establish extirpated wild populations. A captive breeding program for endangered Sakinaw Lake sockeye salmon was established from 84 adults between 2002 and 2005, just prior to extirpation of the wild population. After several years of absence, sockeye salmon released from captivity returned to spawn in Sakinaw Lake in 2010 and in all years thereafter. Freshwater surviv...

  20. Natural resource industries, 'tragedy of the commons' and the case of Chilean salmon farming

    OpenAIRE

    Iizuka, M.; Katz, J

    2010-01-01

    Chilean salmon farming has been considered as an outstanding example of success after growing at double digit rates for more than twenty years. While the expansion was indeed dramatic, it came at the expense of severe sanitary and environmental deterioration. The outbreak in 2008 of the infectious salmon anaemia, a viral disease that kills salmon, but does not affect humans, has made this utterly clear. The overexploitation of the ‘commons’ upon which the industry has grown and the lack of an...