WorldWideScience

Sample records for anadromous brown trout

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

    DEFF Research Database (Denmark)

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

    2004-01-01

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

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

    NARCIS (Netherlands)

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

    2007-01-01

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

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

    Science.gov (United States)

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

    2007-08-01

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

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

    DEFF Research Database (Denmark)

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

    2015-01-01

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

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

    DEFF Research Database (Denmark)

    Olofsson, H.; Mosegaard, Henrik

    1999-01-01

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

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

    OpenAIRE

    Skaala, Øystein; Kålås, Steinar; Borgstrøm, Reidar

    2013-01-01

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

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

    DEFF Research Database (Denmark)

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

    2015-01-01

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

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

    Science.gov (United States)

    Jonsson, B; Jonsson, N

    2015-07-01

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

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

    Science.gov (United States)

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

    2015-11-01

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

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

    DEFF Research Database (Denmark)

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

    2015-01-01

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

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

    DEFF Research Database (Denmark)

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

    2004-01-01

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

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

    OpenAIRE

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

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Thomsen Dennis S

    2008-01-01

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

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

    DEFF Research Database (Denmark)

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

    2008-01-01

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

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

    DEFF Research Database (Denmark)

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

    2002-01-01

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

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

    DEFF Research Database (Denmark)

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

    2004-01-01

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

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

    DEFF Research Database (Denmark)

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

    2001-01-01

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

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

    Science.gov (United States)

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

    2010-01-01

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

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

    OpenAIRE

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

    2008-01-01

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

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

    Science.gov (United States)

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

    2013-01-01

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

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

    DEFF Research Database (Denmark)

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

    2005-01-01

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

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

    Science.gov (United States)

    2014-01-01

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

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

    OpenAIRE

    Kirkemoen, Odin Lagerborg

    2016-01-01

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

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

    DEFF Research Database (Denmark)

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

    2000-01-01

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

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

    Science.gov (United States)

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

    2011-01-01

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

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

    Science.gov (United States)

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

    2007-01-01

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

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

    Science.gov (United States)

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

    2003-01-01

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

  8. Are brown trout replacing or displacing bull trout populations in a changing climate?

    Science.gov (United States)

    Al-Chokhachy, Robert K.; Schmetterling, David A.; Clancy, Chris; Saffel, Pat; Kovach, Ryan; Nyce, Leslie; Liermann, Brad; Fredenberg, Wade A.; Pierce, Ron

    2016-01-01

    Understanding how climate change may facilitate species turnover is an important step in identifying potential conservation strategies. We used data from 33 sites in western Montana to quantify climate associations with native bull trout (Salvelinus confluentus) and non-native brown trout (Salmo trutta) abundance and population growth rates (λ). We estimated λ using exponential growth state space models and delineated study sites based on bull trout use for either Spawning and Rearing (SR) or Foraging, Migrating, and Overwintering (FMO) habitat. Bull trout abundance was negatively associated with mean August stream temperatures within SR habitat (r = -0.75). Brown trout abundance was generally highest at temperatures between 12 and 14°C. We found bull trout λ were generally stable at sites with mean August temperature below 10°C but significantly decreasing, rare, or extirpated at 58% of the sites with temperatures exceeding 10°C. Brown trout λ were highest in SR and sites with temperatures exceeding 12°C. Declining bull trout λs at sites where brown trout were absent suggests brown trout are likely replacing bull trout in a warming climate.

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

    Science.gov (United States)

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

    2000-01-01

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

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

    Science.gov (United States)

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

    2002-01-01

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

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

    Science.gov (United States)

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

    1998-01-01

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

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

    Data.gov (United States)

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

  13. Some Direct Gillnet Selectivity Tests for Brown Trout Populations

    OpenAIRE

    O Grady, M. F.

    1981-01-01

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

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

    Science.gov (United States)

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

    2004-01-01

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

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

    OpenAIRE

    Meredith, Christy

    2012-01-01

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

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

    Science.gov (United States)

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

    2011-01-01

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

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

    Science.gov (United States)

    Korsu, Kai; Huusko, Ari; Muotka, Timo

    2009-03-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2003-01-01

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

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

    Science.gov (United States)

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

    2011-09-01

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

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

    OpenAIRE

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

    2008-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    DEFF Research Database (Denmark)

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

    2001-01-01

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

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

    DEFF Research Database (Denmark)

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

    2001-01-01

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

  6. Animal welfare in brown trout farming: hematological results

    Directory of Open Access Journals (Sweden)

    G. Forneris

    2010-01-01

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

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2003-01-01

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

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

    OpenAIRE

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2010-01-01

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

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

    OpenAIRE

    Snoj Aleš; Simonović Predrag; Sušnik Simona; Marić Saša

    2006-01-01

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

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

    OpenAIRE

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

    Ceola, S.; Pugliese, A.

    2014-09-01

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

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

    Science.gov (United States)

    Carline, R.F.

    2006-01-01

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

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

    Science.gov (United States)

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

    2008-07-01

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

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

    Science.gov (United States)

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

    2007-01-01

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

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

    Science.gov (United States)

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

    2009-01-01

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

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

    OpenAIRE

    Srečko Lainer

    1995-01-01

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

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

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

    Science.gov (United States)

    Ward, David L.; Morton-Starner, Rylan

    2015-01-01

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

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

    DEFF Research Database (Denmark)

    Hansen, Michael Møller; Mensberg, Karen-Lise Dons

    2009-01-01

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

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

    OpenAIRE

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

    2006-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Makhrov Alexander

    2013-03-01

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

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

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

    OpenAIRE

    Makhrov Alexander

    2013-01-01

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

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

    DEFF Research Database (Denmark)

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

    2003-01-01

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

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

    OpenAIRE

    HOLLAND, CELIA

    2004-01-01

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

  9. Intercohort density dependence drives brown trout habitat selection

    Science.gov (United States)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2014-06-01

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

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

    OpenAIRE

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

    2015-01-01

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

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

    OpenAIRE

    Ottaway, E.M.; Clarke, A.

    1981-01-01

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

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

    OpenAIRE

    Frank, Béatrice

    2012-01-01

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

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

    OpenAIRE

    Marić, Saša; Simonović, Predrag; Razpet, Andrej

    2010-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Blaž Cokan

    2013-12-01

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

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

    OpenAIRE

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

    2015-01-01

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

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

    Science.gov (United States)

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

    1995-01-01

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

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

    Science.gov (United States)

    Meerbeek, Jonathan R.; Bettoli, Phillip William

    2012-01-01

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

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

    DEFF Research Database (Denmark)

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

    2001-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Srečko Lainer

    1995-03-01

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

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

    OpenAIRE

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

    2015-01-01

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

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

    OpenAIRE

    Ulvan, Eva Marita

    2010-01-01

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

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

    OpenAIRE

    Ahmet ALP; Erer, Mesut; KAMALAK, Adem

    2010-01-01

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

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

    DEFF Research Database (Denmark)

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

    2002-01-01

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

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

    OpenAIRE

    Clifton-Dey , D.; Walsingham, M.

    1996-01-01

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

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

    OpenAIRE

    Blaž Cokan; Blaž Repe

    2013-01-01

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

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

    Science.gov (United States)

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

    2015-05-21

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

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

    Science.gov (United States)

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

    2015-05-21

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

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

    OpenAIRE

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2016-10-01

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

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

    DEFF Research Database (Denmark)

    Hansen, Michael Møller; Mensberg, Karen-Lise Dons

    1996-01-01

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

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

    OpenAIRE

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

    2012-01-01

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

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

    OpenAIRE

    Burbank, Nora K.

    2011-01-01

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

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

    DEFF Research Database (Denmark)

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

    2012-01-01

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

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

    OpenAIRE

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

    2011-01-01

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

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

    OpenAIRE

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

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Ali Jaffal

    2015-09-01

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

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2005-01-01

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

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

    Science.gov (United States)

    Leland, H.V.

    1983-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Kristian Meier

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

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

    DEFF Research Database (Denmark)

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

    2003-01-01

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

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

    OpenAIRE

    Diamond, Sian

    2012-01-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    OpenAIRE

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

    2013-01-01

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

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

    OpenAIRE

    Lans, Linnea

    2012-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Stelkens Rike B

    2012-12-01

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

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

    OpenAIRE

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

    2009-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Snoj Aleš

    2006-06-01

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

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

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

    DEFF Research Database (Denmark)

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

    2000-01-01

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

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

    Science.gov (United States)

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

    1995-01-01

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

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

    DEFF Research Database (Denmark)

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

    2010-01-01

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

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

    DEFF Research Database (Denmark)

    Hansen, Michael Møller; Jensen, L. F.

    2005-01-01

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

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

    2008-11-01

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

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

    DEFF Research Database (Denmark)

    Hansen, Michael Møller

    2002-01-01

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

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

    Science.gov (United States)

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

    2015-06-01

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

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

    DEFF Research Database (Denmark)

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

    2008-01-01

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

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

    OpenAIRE

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

    2014-01-01

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

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

    OpenAIRE

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

    2005-01-01

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

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

    Science.gov (United States)

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

    2014-10-04

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

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Jose Luis Horreo

    2014-09-01

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

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

    OpenAIRE

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

    2005-01-01

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

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

    DEFF Research Database (Denmark)

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

    2009-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Resende Albina D

    2003-03-01

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

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

    OpenAIRE

    Jansson, Julia

    2015-01-01

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

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

    OpenAIRE

    Gustafsson, Pär

    2008-01-01

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

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

    OpenAIRE

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

    2014-01-01

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

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

    OpenAIRE

    Buffam, Ishi

    2007-01-01

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

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

    Science.gov (United States)

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

    2010-12-01

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

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

    Science.gov (United States)

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

    2015-11-01

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

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

    DEFF Research Database (Denmark)

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

    2009-01-01

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

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

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    Saeed Hajirezaee

    2009-01-01

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

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

    Science.gov (United States)

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

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Javier Sánchez-Hernández

    2016-07-01

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

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

    Science.gov (United States)

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

    2006-10-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Quilichini Y.

    2007-09-01

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

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

    Science.gov (United States)

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

    2013-04-29

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

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

    Science.gov (United States)

    Fost, B A; Ferreri, C P

    2015-08-01

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

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

    Directory of Open Access Journals (Sweden)

    Peter A H Westley

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

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

    Science.gov (United States)

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

    1998-01-01

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

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

    Science.gov (United States)

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

    2012-01-01

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

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

    Science.gov (United States)

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

    2015-04-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Conallin J.

    2014-03-01

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

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

    DEFF Research Database (Denmark)

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

    2008-01-01

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

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

    NARCIS (Netherlands)

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

    2005-01-01

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

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

    Directory of Open Access Journals (Sweden)

    A. Mruk

    2013-03-01

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

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

    OpenAIRE

    Burkhardt-Holm, Patricia

    2008-01-01

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

  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

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

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

    Directory of Open Access Journals (Sweden)

    Azarmidokht Kheyrandish

    2010-01-01

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

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

    DEFF Research Database (Denmark)

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

    2006-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-12-15

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

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

    Science.gov (United States)

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

    2007-07-01

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

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

    Science.gov (United States)

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

    1999-02-01

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

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

    Directory of Open Access Journals (Sweden)

    L Fredrik Sundström

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

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

    Science.gov (United States)

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

    1999-02-01

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

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

    Science.gov (United States)

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

    2015-04-01

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

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

    DEFF Research Database (Denmark)

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

    1997-01-01

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

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

    DEFF Research Database (Denmark)

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

    1997-01-01

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

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

    OpenAIRE

    2007-01-01

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

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

    OpenAIRE

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2010-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Ágnes Ősz

    2015-12-01

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

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

    Science.gov (United States)

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

    2015-06-01

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

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

    DEFF Research Database (Denmark)

    Jacobsen, Lene

    2005-01-01

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

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

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    Ioan Bud

    2009-01-01

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

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

    Science.gov (United States)

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

    2015-07-01

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

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

    Science.gov (United States)

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

    2008-05-01

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

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

    Science.gov (United States)

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

    2006-04-01

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

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

    Directory of Open Access Journals (Sweden)

    RANDÁK T.

    2006-07-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2010-04-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

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

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

    Directory of Open Access Journals (Sweden)

    S. J. Ormerod

    2004-01-01

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

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

    Science.gov (United States)

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

    2016-09-01

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

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

    DEFF Research Database (Denmark)

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

    2012-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1985-01-01

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

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

    Science.gov (United States)

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

    1997-01-01

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

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

    Science.gov (United States)

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

    2015-08-01

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

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

    Science.gov (United States)

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

    2015-08-01

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

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

    OpenAIRE

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

    2016-01-01

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

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

    OpenAIRE

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

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Urška Sivka

    2012-07-01

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

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

    Science.gov (United States)

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

    2015-10-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-01-09

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

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

    Science.gov (United States)

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

    2016-03-01

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

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

    Directory of Open Access Journals (Sweden)

    José E. Larios-López

    2015-01-01

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

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

    Science.gov (United States)

    Shirdel, Iman; Kalbassi, Mohammad Reza

    2016-01-01

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

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

    Science.gov (United States)

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

    2015-06-01

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

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

    Science.gov (United States)

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

    2016-02-15

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

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

    Science.gov (United States)

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

    2016-02-01

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

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-01-25

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

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

    Directory of Open Access Journals (Sweden)

    S Leiner

    1995-06-01

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

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

    DEFF Research Database (Denmark)

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

    2004-01-01

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

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

    NARCIS (Netherlands)

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

    2006-01-01

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

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

    DEFF Research Database (Denmark)

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

    2009-01-01

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

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

    Science.gov (United States)

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

    2001-01-01

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

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

    Science.gov (United States)

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

    2001-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Tibor Erős

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

  7. A synthesis of tagging studies examining the behaviour and survival of anadromous salmonids in marine environments.

    Directory of Open Access Journals (Sweden)

    S Matthew Drenner

    Full Text Available This paper synthesizes tagging studies to highlight the current state of knowledge concerning the behaviour and survival of anadromous salmonids in the marine environment. Scientific literature was reviewed to quantify the number and type of studies that have investigated behaviour and survival of anadromous forms of Pacific salmon (Oncorhynchus spp., Atlantic salmon (Salmo salar, brown trout (Salmo trutta, steelhead (Oncorhynchus mykiss, and cutthroat trout (Oncorhynchus clarkii. We examined three categories of tags including electronic (e.g. acoustic, radio, archival, passive (e.g. external marks, Carlin, coded wire, passive integrated transponder [PIT], and biological (e.g. otolith, genetic, scale, parasites. Based on 207 papers, survival rates and behaviour in marine environments were found to be extremely variable spatially and temporally, with some of the most influential factors being temperature, population, physiological state, and fish size. Salmonids at all life stages were consistently found to swim at an average speed of approximately one body length per second, which likely corresponds with the speed at which transport costs are minimal. We found that there is relatively little research conducted on open-ocean migrating salmonids, and some species (e.g. masu [O. masou] and amago [O. rhodurus] are underrepresented in the literature. The most common forms of tagging used across life stages were various forms of external tags, coded wire tags, and acoustic tags, however, the majority of studies did not measure tagging/handling effects on the fish, tag loss/failure, or tag detection probabilities when estimating survival. Through the interdisciplinary application of existing and novel technologies, future research examining the behaviour and survival of anadromous salmonids could incorporate important drivers such as oceanography, tagging/handling effects, predation, and physiology.

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

    Directory of Open Access Journals (Sweden)

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

    2010-10-01

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

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

    DEFF Research Database (Denmark)

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

    2016-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-06-25

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-09-01

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

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

    Science.gov (United States)

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

    2010-05-01

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

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

    Science.gov (United States)

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

    2009-01-01

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

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

    DEFF Research Database (Denmark)

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

    2001-01-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    DEFF Research Database (Denmark)

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

    2000-01-01

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

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

    OpenAIRE

    Kara, Cemil

    2005-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Manuela Turković

    2006-07-01

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

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Emilie Réalis-Doyelle

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

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

    DEFF Research Database (Denmark)

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

    2000-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Vandeputte Marc

    2004-11-01

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

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

    Science.gov (United States)

    Iwasaki, Yuichi; Brinkman, Stephen F

    2015-04-01

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

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

    Science.gov (United States)

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

    2016-06-01

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

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

    Directory of Open Access Journals (Sweden)

    Claudio S Quilodrán

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

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

    Science.gov (United States)

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

    2014-01-01

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

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

    DEFF Research Database (Denmark)

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

    2008-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Tamara Schenekar

    2015-11-01

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

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

    Science.gov (United States)

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

    2015-09-01

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

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

    Directory of Open Access Journals (Sweden)

    Rasmus Kaspersson

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

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

    OpenAIRE

    Iversen, Elisabeth

    2011-01-01

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

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

    Science.gov (United States)

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

    2013-04-01

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

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

    Science.gov (United States)

    Cunningham, Jessie L; McGeer, James C

    2016-04-01

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

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

    Science.gov (United States)

    Cunningham, Jessie L; McGeer, James C

    2016-04-01

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

  16. Marine migrations in anadromous brown trout (Salmo trutta). Fjord residency as a possible alternative in the continuum of migration to the open sea

    DEFF Research Database (Denmark)

    Del Villar, Diego; Aarestrup, Kim; Skov, Christian;

    2014-01-01

    with acoustic and PIT-tags in the river Villestrup (Denmark) to study the initial postsmolt marine behaviour within a fjord system. We found that the strategies of the sea migrants vary: some stay in the fjord, while others migrate to the sea, suggesting that partial migration occurs even in the marine...... of the smolts were observed. The individual’s size or body condition at the time of tagging did not affect survival or the migratory decisions in the fjord. High overall initial survival (74%) was found 30 days after the fjord entry. We suggest that within a continuum of migration to sea, there is a migratory...

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

    Directory of Open Access Journals (Sweden)

    Ayse Er

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Mark C. Belk

    2016-03-01

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

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

    Science.gov (United States)

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

    2015-08-01

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

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

    Science.gov (United States)

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

    2016-02-01

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

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

    DEFF Research Database (Denmark)

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

    2002-01-01

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

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

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

    DEFF Research Database (Denmark)

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

    2008-01-01

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

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

    Science.gov (United States)

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

    2014-07-01

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

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

    Directory of Open Access Journals (Sweden)

    Jose L. Horreo

    2015-07-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2015-12-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2011-12-01

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

  11. 78 FR 23222 - Endangered and Threatened Species; Take of Anadromous Fish

    Science.gov (United States)

    2013-04-18

    ... Anadromous Fish AGENCY: NOAA's National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric... November 14, 2012 (77 FR 67796). Permit 15610 was issued to OSU on March 4, 2013. Permit 15610 authorizes... genetic structure exists in the steelhead and rainbow trout subpopulations in the Ventura Basin,...

  12. Survival of Trout Strains as Affected by Limnological Parameters

    OpenAIRE

    Wurtsbaugh, Wayne A.

    1988-01-01

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

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

    Science.gov (United States)

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

    2015-11-01

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

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

    Science.gov (United States)

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

    2015-11-01

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

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

    Science.gov (United States)

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

    2005-05-01

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

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

    Science.gov (United States)

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

    2015-12-01

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

  17. Predicting recolonization patterns and interactions between potamodromous and anadromous salmonids in response to dam removal in the Elwha River, Washington State, USA

    Science.gov (United States)

    Brenkman, S.J.; Pess, G.R.; Torgersen, C.E.; Kloehn, K.K.; Duda, J.J.; Corbett, S.C.

    2008-01-01

    The restoration of salmonids in the Elwha River following dam removal will cause interactions between anadromous and potamodromous forms as recolonization occurs in upstream and downstream directions. Anadromous salmonids are expected to recolonize historic habitats, and rainbow trout (Oncorhynchus mykiss) and bull trout (Salvelinus confluentus) isolated above the dams for 90 years are expected to reestablish anadromy. We summarized the distribution and abundance of potamodromous salmonids, determined locations of spawning areas, and mapped natural barriers to fish migration at the watershed scale based on data collected from 1993 to 2006. Rainbow trout were far more abundant than bull trout throughout the watershed and both species were distributed up to river km 71. Spawning locations for bull trout and rainbow trout occurred in areas where we anticipate returning anadromous fish to spawn. Nonnative brook trout were confined to areas between and below the dams, and seasonal velocity barriers are expected to prevent their upstream movements. We hypothesize that the extent of interaction between potamodromous and anadromous salmonids will vary spatially due to natural barriers that will limit upstream-directed recolonization for some species of salmonids. Consequently, most competitive interactions will occur in the main stem and floodplain downstream of river km 25 and in larger tributaries. Understanding future responses of Pacific salmonids after dam removal in the Elwha River depends upon an understanding of existing conditions of the salmonid community upstream of the dams prior to dam removal.

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

    Science.gov (United States)

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

    2012-10-01

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

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

    OpenAIRE

    HOLLAND, CELIA

    2002-01-01

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

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

    Science.gov (United States)

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

    2015-06-01

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

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

    Science.gov (United States)

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

    2012-12-01

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

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

    DEFF Research Database (Denmark)

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

    2002-01-01

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

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

    Science.gov (United States)

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

    2011-01-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    LAGARRIGUE T.

    2008-05-01

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

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

    DEFF Research Database (Denmark)

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

    2011-01-01

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

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

    Science.gov (United States)

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

    2000-01-01

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

  8. Metabolic fates and effects of nitrite in brown trout under normoxic and hypoxic conditions: blood and tissue nitrite metabolism and interactions with branchial NOS, Na+/K+-ATPase and hsp70 expression.

    Science.gov (United States)

    Jensen, Frank B; Gerber, Lucie; Hansen, Marie N; Madsen, Steffen S

    2015-07-01

    Nitrite secures essential nitric oxide (NO) bioavailability in hypoxia at low endogenous concentrations, whereas it becomes toxic at high concentrations. We exposed brown trout to normoxic and hypoxic water in the absence and presence of added ambient nitrite to decipher the cellular metabolism and effects of nitrite at basal and elevated concentrations under different oxygen regimes. We also tested hypotheses concerning the influence of nitrite on branchial nitric oxide synthase (NOS), Na(+)/K(+)-ATPase (nka) and heat shock protein (hsp70) mRNA expression. Basal plasma and erythrocyte nitrite levels were higher in hypoxia than normoxia, suggesting increased NOS activity. Nitrite exposure strongly elevated nitrite concentrations in plasma, erythrocytes, heart tissue and white muscle, which was associated with an extensive metabolism of nitrite to nitrate and to iron-nitrosylated and S-nitrosated compounds. Nitrite uptake was slightly higher in hypoxia than normoxia, and high internal nitrite levels extensively converted blood hemoglobin to methemoglobin and nitrosylhemoglobin. Hypoxia increased inducible NOS (iNOS) mRNA levels in the gills, which was overruled by a strong inhibition of iNOS expression by nitrite in both normoxia and hypoxia, suggesting negative-feedback regulation of iNOS gene expression by nitrite. A similar inhibition was absent for neuronal NOS. Branchial NKA activity stayed unchanged, but mRNA levels of the nkaα1a subunit increased with hypoxia and nitrite, which may have countered an initial NKA inhibition. Nitrite also increased hsp70 gene expression, probably contributing to the cytoprotective effects of nitrite at low concentrations. Nitrite displays a concentration-dependent switch between positive and negative effects similar to other signaling molecules. PMID:25908056

  9. Metabolic fates and effects of nitrite in brown trout under normoxic and hypoxic conditions: blood and tissue nitrite metabolism and interactions with branchial NOS, Na+/K+-ATPase and hsp70 expression

    DEFF Research Database (Denmark)

    Jensen, Frank Bo; Gerber, Lucie; Hansen, Marie Niemann;

    2015-01-01

    Nitrite secures essential nitric oxide (NO) bioavailability in hypoxia at low endogenous concentrations, whereas it becomes toxic at high concentrations. We exposed brown trout to normoxic and hypoxic water in the absence and presence of added ambient nitrite to decipher the cellular metabolism and...... were higher in hypoxia than normoxia, suggesting increased NOS activity. Nitrite exposure strongly elevated nitrite concentrations in plasma, erythrocytes, heart tissue and white muscle, which was associated with an extensive metabolism of nitrite to nitrate and to iron-nitrosylated and S...

  10. Movement of resident rainbow trout transplanted below a barrier to anadromy

    Science.gov (United States)

    Wilzbach, Margaret A.; Ashenfelter, Mark J.; Ricker, Seth J.

    2012-01-01

    We tracked the movement of resident coastal rainbow trout Oncorhynchus mykiss irideus that were experimentally transplanted below a migration barrier in a northern California stream. In 2005 and 2006, age-1 and older rainbow trout were captured above a 5-m-high waterfall in Freshwater Creek and individually marked with passive integrated transponder tags. Otolith microchemistry confirmed that the above-barrier trout were the progeny of resident rather than anadromous parents, and genetic analysis indicated that the rainbow trout were introgressed with cutthroat trout O. clarkii. At each of three sampling events, half of the tagged individuals (n = 22 and 43 trout in 2005 and 2006, respectively) were released 5 km downstream from the waterfall (approximately 10 km upstream from tidewater), and an equal number of tagged individuals were released above the barrier. Tagged individuals were subsequently relocated with stationary and mobile antennae or recaptured in downstream migrant traps, or both, until tracking ceased in October 2007. Most transplanted individuals remained within a few hundred meters of their release location. Three individuals, including one rainbow trout released above the waterfall, were last detected in the tidally influenced lower creek. Two additional tagged individuals released above the barrier were found alive in below-barrier reaches and had presumably washed over the falls. Two of seven tagged rainbow trout captured in downstream migrant traps had smolted and one was a presmolt. The smoltification of at least some individuals, coupled with above-barrier "leakage" of fish downstream, suggests that above-barrier resident trout have the potential to exhibit migratory behavior and to enter breeding populations of steelhead (anadromous rainbow trout) within the basin.

  11. Restoring Anadromous Fish Habitat in the Lapwai Creek Watershed, Technical Report 2003-2006.

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, Lynn

    2007-02-01

    The Restoring Anadromous Fish Habitat in the Lapwai Creek Watershed is a multi-phase project to enhance steelhead trout in the Lapwai Creek watershed by improving salmonid spawning and rearing habitat. Habitat is limited by extreme high runoff events, low summer flows, high water temperatures, poor instream cover, spawning gravel siltation, and sediment, nutrient and bacteria loading. Funded by the Bonneville Power Administration (BPA) as part of the Northwest Power Planning Council's Fish and Wildlife Program, the project assists in mitigating damage to steelhead runs caused by the Columbia River hydroelectric dams. The project is sponsored by the Nez Perce Soil and Water Conservation District (District). Target fish species include steelhead trout (Oncorhynchus mykiss). Steelhead trout within the Snake River Basin were listed in 1997 as threatened under the Endangered Species Act. Accomplishments for the contract period December 1, 2003 through February 28, 2004 include; seven grade stabilization structures, 0.67 acres of wetland plantings, ten acres tree planting, 500 linear feet streambank erosion control, two acres grass seeding, and 120 acres weed control.

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

    OpenAIRE

    Lokteff, Ryan L.

    2014-01-01

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

  13. Impact of beaver dams on abundance and distribution of anadromous salmonids in two lowland streams in Lithuania.

    Directory of Open Access Journals (Sweden)

    Tomas Virbickas

    Full Text Available European beaver dams impeded movements of anadromous salmonids as it was established by fishing survey, fish tagging and redd counts in two lowland streams in Lithuania. Significant differences in abundancies of other litophilic fish species and evenness of representation by species in the community were detected upstream and downstream of the beaver dams. Sea trout parr marked with RFID tags passed through several successive beaver dams in upstream direction, but no tagged fish were detected above the uppermost dam. Increase in abundances of salmonid parr in the stream between the beaver dams and decrease below the dams were recorded in November, at the time of spawning of Atlantic salmon and sea trout, but no significant changes were detected in the sections upstream of the dams. After construction of several additional beaver dams in the downstream sections of the studied streams, abundance of Atlantic salmon parr downstream of the dams decreased considerably in comparison with that estimated before construction.

  14. Life+ Trout Project (LIFE12 NAT/IT/0000940) for the recovery and conservation of Mediterranean trout (Salmo trutta complex) in the central Apennines (Italy).

    OpenAIRE

    Vincenzo Caputo Barucchi; Antonella Carosi

    2015-01-01

    The Mediterranean brown trout (Salmo trutta complex) is one of the freshwater fish species complex at greater risk of extinction in the Mediterranean area. The introduction of alien invasive species and their interaction with the native fauna represent some of the major threats to the survival of this species (Caputo et al., 2004). Currently, the genetic integrity of the Mediterranean trout is being compromised by the introgressive hybridization with the Atlantic trout. This hybridization, wh...

  15. Camas Creek (Meyers Cove) Anadromous Species Habitat Improvement: Annual Report 1990.

    Energy Technology Data Exchange (ETDEWEB)

    Seaberg, Glen

    1990-06-01

    Populations of wild salmon and steelhead in the Middle Fork of the Salmon River are at historical lows. Until passage and flow problems associated with Columbia River dams are corrected to reduce mortalities of migrating smolts, continuance of habitat enhancements that decrease sediment loads, increase vegetative cover, remove passage barriers, and provide habitat diversity is imperative to maintain surviving populations of these specially adapted fish. In 1987-1988, 4.3 miles of fence was constructed establishing a riparian livestock exclosure. One end-gap and two water-crossing corridors were constructed in 1989 to complete the fence system. Areas within the exclosure have been fertilized to promote tree and shrub root growth and meadow recovery. A stream crossing ford was stabilized with angular cobble. Streambank stabilization/habitat cover work was completed at three sites and three additional habitat structures were placed. Extensive inventories were completed to identify habitat available to anadromous fish. Streambank stabilization work was limited to extremely unstable banks, minimizing radical alterations to an active stream channel. Enhancement activities will improve spawning, incubation, and rearing habitat for wild populations of steelhead trout and chinook salmon. Anadromous species population increases resulting from these enhancement activities will provide partial compensation for downstream losses resulting from hydroelectric developments on the Columbia River system. 10 refs., 11 figs., 5 tabs.

  16. Camas Creek (Meyers Cove) Anadromous Species Habitat Improvement: Annual Report 1989.

    Energy Technology Data Exchange (ETDEWEB)

    Hardy, Terry

    1989-12-01

    Historical agricultural practices and natural events contributed to severe degradation of riparian zones and instream fish habitat in the Meyers Cove area of Camas Creek. In 1984, Salmon National Forest personnel began implementing specific management activities in riparian areas and the stream channel to accelerate habitat recovery. In 1987--88, 4.3 miles of fence was constructed establishing a riparian livestock exclosure in the Meyers Cove area of Camas Creek. One end-gap and two water-crossing corridors were constructed in 1989 to complete the fence system. The riparian exclosure has been fertilized with phosphorous-rich fertilizer to promote root growth. A stream crossing ford was stabilized with angular cobble. Streambank stabilization/habitat cover work was completed at three sites and three additional habitat structures were placed. Extensive habitat inventories were completed to identify quality/quantity of habitat available to anadromous fish. The work accomplished was designed to promote natural revegetation of the riparian area to improve rearing habitat cover and streambank stability. Streambank work was limited to extremely unstable sites. Enhancement activities will improve spawning, incubation, and rearing habitat for wild populations of steelhead trout and chinook salmon. Anadromous species population increases resulting from these enhancement activities will provide partial compensation for downstream losses resulting from hydroelectric developments on the Columbia River system. 9 refs., 6 figs., 7 tabs.

  17. Overwintering of sea trout (Salmo trutta) in freshwater

    DEFF Research Database (Denmark)

    Thomsen, Dennis; Koed, Anders; Nielsen, Christian;

    2007-01-01

    Brown trout (Salmo trutta) show large phenotypic plasticity. Juveniles may reside in their native freshwater habitat until maturation or migrate into the ocean as 1- to 3-year-old smolts. Sea-going fish (sea trout) reside at sea for 2-3 years until migrating back to their native stream for reprod...

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

    International Nuclear Information System (INIS)

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

  19. 腐植酸在褐鳟鱼鳃和肌肉抵抗镉中毒的组织病理学和生物化学作用%Histopathological and Biochemical Effects of Humic Acid Against Cadmium Toxicity in Brown Trout Gills and Muscles

    Institute of Scientific and Technical Information of China (English)

    Gonca Alak; Muhammed Atamanalp; Ahmet Topal; Harun Arslan; Ertan Oruç; Serdar Altun; 李双(译)

    2015-01-01

    It was biochemically and histopathologically investigated whether humic acid (HA) has protective effects on cadmium (Cd) toxicity on muscle and gills of brown trout. The brown trout were exposed to cadmium (2ppm) and/or humic acid (5ppm). For this purpose, levels of glutathione peroxidase (GPx), superoxide dismutase (SOD), malondi-aldehyde (MDA) was investigated in muscle and gills tissues of brown trout. The activities of GPx and SOD in the tis-sues of ifsh exposed to Cd was signiifcantly lower than the control groups (P0.05). Hovewer, humic acid did not affect biochemical damage in cadmium group. Cd caused a signiifcant increase in histopathological changes in muscle and gills tissues, but histopathological changes were lower in the muscle tissue of Cd+HA group. These results suggest that humic acid may counteract the cadmium toxicity in muscles tissue in histopathologic aspect.%为了探究腐植酸(HA)对褐鳟鱼鳃和肌肉在抵抗镉(Cd)中毒方面是否发挥积极作用,进行了组织病理学和生物化学方面的研究。试验中,褐鳟暴露在仅施加2 ppm镉,施加2 ppm镉加5 ppm腐植酸,仅施加5 ppm腐植酸的3种环境条件下,分别测定其鳃和肌肉组织的谷胱甘肽过氧化物酶(G P x)、超氧化物歧化酶(S O D)、丙二醛(M D A)水平。在含镉条件下,褐鳟组织中的G P x和S O D活性显著低于对照组(P0.05)。然而,腐植酸并未影响镉造成的生化伤害。镉对鱼鳃和肌肉组织造成明显的组织病理学变化,而在镉+腐植酸处理组中,肌肉组织病理学变化较小。这些结果表明,腐植酸可从组织病理学方面中和肌肉组织镉中毒。

  20. BASEMAP, BROWN COUNTY, WISCONSIN TROUT CREEK PMR

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — FEMA Framework Basemap datasets comprise six of the seven FGDC themes of geospatial data that are used by most GIS applications (Note: the seventh framework theme,...

  1. Restoring Anadromous Fish Habitat in Big Canyon Creek Watershed, 2004-2005 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, Lynn (Nez Perce Soil and Conservation District, Lewiston, ID)

    2006-07-01

    The ''Restoring Anadromous Fish Habitat in the Big Canyon Creek Watershed'' is a multi-phase project to enhance steelhead trout in the Big Canyon Creek watershed by improving salmonid spawning and rearing habitat. Habitat is limited by extreme high runoff events, low summer flows, high water temperatures, poor instream cover, spawning gravel siltation, and sediment, nutrient and bacteria loading. Funded by the Bonneville Power Administration (BPA) as part of the Northwest Power Planning Council's Fish and Wildlife Program, the project assists in mitigating damage to steelhead runs caused by the Columbia River hydroelectric dams. The project is sponsored by the Nez Perce Soil and Water Conservation District. Target fish species include steelhead trout (Oncorhynchus mykiss). Steelhead trout within the Snake River Basin were listed in 1997 as threatened under the Endangered Species Act. Accomplishments for the contract period September 1, 2004 through October 31, 2005 include; 2.7 riparian miles treated, 3.0 wetland acres treated, 5,263.3 upland acres treated, 106.5 riparian acres treated, 76,285 general public reached, 3,000 students reached, 40 teachers reached, 18 maintenance plans completed, temperature data collected at 6 sites, 8 landowner applications received and processed, 14 land inventories completed, 58 habitat improvement project designs completed, 5 newsletters published, 6 habitat plans completed, 34 projects installed, 2 educational workshops, 6 displays, 1 television segment, 2 public service announcements, a noxious weed GIS coverage, and completion of NEPA, ESA, and cultural resources requirements.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-02-01

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

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

    Science.gov (United States)

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

    1999-01-01

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

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

    OpenAIRE

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

    2015-01-01

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

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

    OpenAIRE

    Fahy, E

    1982-01-01

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

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

    Science.gov (United States)

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

    2012-01-01

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

  7. Evaluation of angler effort and harvest of rainbow trout (Oncorhynchus mykiss), Lake Scanewa, Washington, 2010

    Science.gov (United States)

    Liedtke, Theresa L.; Kock, Tobias J.; Ekstrom, Brian K.; Tomka, Ryan G.; Rondorf, Dennis W.

    2011-01-01

    A creel evaluation was conducted in Lake Scanewa, a reservoir on the Cowlitz River, to monitor catch rates of rainbow trout (Oncorhynchus mykiss) and determine if the trout fishery was having negative impacts on juvenile anadromous salmon (Oncorhynchus spp.) in the system. The trout fishery, which is supported by releases of 20,000 fish (2 fish per pound) per year from June to August, was developed to mitigate for the construction of the Cowlitz Falls Dam in 1994. The trout fishery has a target catch rate of at least 0.50 fish per hour. Interviews with 1,214 anglers during the creel evaluation found that most anglers targeted rainbow trout (52 percent) or Chinook and coho salmon (48 percent). The interviewed anglers caught a total of 1,866 fish, most of which were rainbow trout (1,213 fish; 78 percent) or coho salmon (311 fish; 20 percent). We estimated that anglers spent 17,365 hours fishing in Lake Scanewa from June to November 2010. Catch rates for boat anglers (1.39 fish per hour) exceeded the 0.50 fish per hour target, whereas catch rates for shore anglers (0.35 fish per hour) fell short of the goal. The combined catch rates for all trout anglers in the reservoir were 0.96 fish per hour. We estimated that anglers harvested 7,584 (95 percent confidence interval = 2,795-12,372 fish) rainbow trout during the study period and boat anglers caught more fish than shore anglers (5,975 and 1,609 fish, respectively). This estimate suggests that more than 12,000 of the 20,000 rainbow trout released into Lake Scanewa during 2010 were not harvested, and could negatively impact juvenile salmon in the reservoir through predation or competition. We examined 1,236 stomach samples from rainbow trout and found that 2.1 percent (26 fish) of these samples contained juvenile fish. Large trout (greater than 300 millimeters) had a higher incidence of predation than small trout (less than 300 millimeters; 8.50 and 0.06 percent, respectively). A total of 39 fish were found in rainbow

  8. An epizootic among rainbow trout

    Science.gov (United States)

    1953-01-01

    An epizootic among rainbow trout (Salmo gairdnerii) in a private trout farm, resulting from a species of Ichthyosporidium that caused very high mortality rates in all ages of trout, reported from the State of Washington.

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

    Institute of Scientific and Technical Information of China (English)

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

    2008-01-01

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

  10. Outplanting Anadromous Salmonids, A Lilterature Study.

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Eugene M.

    1985-10-01

    This paper presents a list of more than 200 references on topics associated with offstation releases of hatchery stocks of anadromous fish used to supplement or reestablish wild rearing. The narrative briefly reviews influences of genetics, rearing density of fish in the natural environment, survival rates observed from outplanted stocks, and estimation procedures for stocking rates and rearing densities. We have attempted to summarize guidelines and recommendations for fishery managers to consider. Based on tagging studies, a typical smolt release from a Willamette River hatchery would return 0.29% of the smolts to the stream of release as adults. Catch to escapement ratios for adult Willamette chinook vary widely between broods, but on average two fish are caught for each fish that escapes. The catch is about evenly divided between offshore and freshwater harvest. British Columbia is the primary location of offshore harvest, and the lower Willamette River is the primary location of freshwater harvest. Review of departmental policy indicates that only Willamette stock spring chinook are currently acceptable for use in a proposed outplant study within the Willamette basin. Further, most Oregon Department of Fish and Wildlife district management biologists would prefer not to transfer any stocks of spring chinook between drainage subbasins. State fishery managers identified 16 Willamette basin streams as being suitable for supplementation with spring chinook from hatcheries. We reviewed the potential for rearing salmon in reservoirs throughout the basin. Use of the Carmen-Smith spawning channel, which was constructed on the upper McKenzie River in 1960, has generally declined with the decline in populations of chinook salmon in this river. The Carmen-Smith channel still provides a spawning place for those relatively few adult chinook that still return each year, but more fishery benefits may result from other uses of this facility. 7 figs., 8 tabs.

  11. Sequence analysis of the internal transcribed spacer (ITS) region reveals a novel clade of Ichthyophonus sp. from rainbow trout

    Science.gov (United States)

    Rasmussen, C.; Purcell, M.K.; Gregg, J.L.; LaPatra, S.E.; Winton, J.R.; Hershberger, P.K.

    2010-01-01

    The mesomycetozoean parasite Ichthyophonus hoferi is most commonly associated with marine fish hosts but also occurs in some components of the freshwater rainbow trout Oncorhynchus mykiss aquaculture industry in Idaho, USA. It is not certain how the parasite was introduced into rainbow trout culture, but it might have been associated with the historical practice of feeding raw, ground common carp Cyprinus carpio that were caught by commercial fisherman. Here, we report a major genetic division between west coast freshwater and marine isolates of Ichthyophonus hoferi. Sequence differences were not detected in 2 regions of the highly conserved small subunit (18S) rDNA gene; however, nucleotide variation was seen in internal transcribed spacer loci (ITS1 and ITS2), both within and among the isolates. Intra-isolate variation ranged from 2.4 to 7.6 nucleotides over a region consisting of ~740 bp. Majority consensus sequences from marine/anadromous hosts differed in only 0 to 3 nucleotides (99.6 to 100% nucleotide identity), while those derived from freshwater rainbow trout had no nucleotide substitutions relative to each other. However, the consensus sequences between isolates from freshwater rainbow trout and those from marine/anadromous hosts differed in 13 to 16 nucleotides (97.8 to 98.2% nucleotide identity).

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

    OpenAIRE

    Teixeira, A; CORTES R. M.V.; D. Oliveira

    2006-01-01

    Habitat use by stocked and native brown trout (Salmo trutta L.) was assessed in two headwater streams of North-eastern Portugal. Underwater observations were made during the summer season in three successive years to evaluate the effect of supplemental trout stocking. Multivariate analysis techniques applied to data sets on microhabitat use were exploited to identify the focal elevation (distance of fish from the bottom), total depth and cover as the variables that contribute most to the disc...

  13. Examining indirect effects of lake trout recovery

    Science.gov (United States)

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

  14. Trout Stream Special Regulations

    Data.gov (United States)

    Minnesota Department of Natural Resources — This layer shows Minnesota trout streams that have a special regulation as described in the 2006 Minnesota Fishing Regulations. Road crossings were determined using...

  15. Study of Meat Physical-Chemical Composition of Three Trout Breeds Farmed in Salmonid Exploitations from Moldova

    Directory of Open Access Journals (Sweden)

    Cătălin Emilian NISTOR

    2014-11-01

    Full Text Available For all trout breeds, especially regarding brown trout, data from local and foreign literature consulted are less conclusive and sometimes controversial in terms of physical-chemical composition of trout meat, so our research represents a first for Romanian literature and aims to bring new information to enrich it.Our research aimed to evaluate the physical-chemical composition of the meat gathered from brook, rainbow and brown trout breed, by analyzing 50 individuals, 10 individuals in each batch (F1, F2, C1 C2 and I1, from two trout farms from Moldova, being determine the pH of meat, dry matter, content in proteins, lipids, ash and water/protein ratio for all three trout breeds. The obtained values for pH at warm ranged between 6.91 at batch F1, and 7.09 for batch I1. As regarding the pH at cold, this one had and descendant evolution ranging between: 6.78 for trout from batch F1 respectively a value of 6.88 for individuals from batch I1. The obtained values were between 23.95 and 27.12 for dry matter. Content in proteins recorded the best values (19.21% at individuals from batch F2, and content in lipids oscillated between 4.14% and 5.62%. The obtained values regarding physical-chemical composition highlighted that all trout breeds have a good nutritional value.

  16. 亚东鲑 Salmo trutta fario 肌肉营养成分分析和品质评价%Analysis and Evaluation of Muscular Nutrition in Brown Trout Salmo trutta fario

    Institute of Scientific and Technical Information of China (English)

    王芳; 户国; 周建设; 谷伟; 李宝海; 白庆利; 王炳谦

    2015-01-01

    N utritionalcom positions in m uscle of brow n troutSalmo trutta fario w ere analyzed by routine m ethods and evaluated by am ino acidsscore(AAS)and chem icalscore(CS).The resultsshow ed thatthe fresh m uscle contained m oisture of70.81% ,crude pro-tein22.63% ,crude fat4.91% and crude ash 1.80% .There w ere totalam ino acid (TA A)of69.51% ,totalessentialam ino acid(EA A) 28.86% and totaldelicious am ino acid (D A A)26.09% in dry m uscle w ith EA A /TA A of41.52% and EA A /N EA A of84.11% .Itw as clearthatthe tw o ratiosin the m uscle w ere in accord w ith the standard ofFA O /W H O(40% and 60% ).The A A S and C S revealed that m ethionine+cysteine and valine w ere the lim ited am ino acids,w ith essentialam ino acidsindex(EAAI)of85.54.A totalof12 kindsof fatty acidsw ere detected in the m uscle ofthe brow n trout,including 19.76% ofsaturated fatty acid (SFA),38.32% ofm onounsaturat-ed fatty acid(M U FA),38.98% ofpolyunsaturated fatty acid(PU FA),and up to 12.31% oftotalcontentofEPA and D H A .In conclu-sion,brow n troutisone ofthe fish w ith good nutritive value and culture values.%本实验通过测定亚东鲑 Salmo trutta fario 肌肉中常规成分、氨基酸含量及脂肪酸含量,评价其营养价值。结果表明:亚东鲑肌肉中水分、粗蛋白、粗脂肪和粗灰分含量分别为70.81%、22.63%、4.91%,和1.80%。除色氨酸水解外,亚东鲑肌肉中17种氨基酸的总量为69.51%,其中必需氨基酸为28.86%,占氨基酸总量的41.52%,符合 FAO/WHO 标准中必需氨基酸构成比例。4种鲜味氨基酸总量为26.09%,其中谷氨酸的含量最高,占鲜味氨基酸总量的41.47%。亚东鲑肌肉的限制性氨基酸为蛋氨酸+胱氨酸和缬氨酸。必需氨基酸指数为85.54。在亚东鲑肌肉中共检出12种脂肪酸,其中单不饱和脂肪酸含量为38.32%,多不饱和脂肪酸含量为38.98%,二十碳五烯酸和二十二碳六烯酸总量达到12.31%。结果表明:亚东鲑肌肉氨基

  17. Male Choice in the Stream-Anadromous Stickleback Complex

    OpenAIRE

    McKinnon, Jeffrey S; Nick Hamele; Nicole Frey; Jennifer Chou; Leia McAleavey; Jess Greene; Windi Paulson

    2012-01-01

    Studies of mating preferences and pre-mating reproductive isolation have often focused on females, but the potential importance of male preferences is increasingly appreciated. We investigated male behavior in the context of reproductive isolation between divergent anadromous and stream-resident populations of threespine stickleback, Gasterosteus aculeatus, using size-manipulated females of both ecotypes. Specifically, we asked if male courtship preferences are present, and if they are based ...

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

    Science.gov (United States)

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

    2016-01-01

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

  19. Individual condition and stream temperature influence early maturation of rainbow and steelhead trout, Oncorhynchus mykiss

    Science.gov (United States)

    McMillan, John R.; Dunham, J.B.; Reeves, G.H.; Mills, J.S.; Jordan, C.E.

    2012-01-01

    Alternative male phenotypes in salmonine fishes arise from individuals that mature as larger and older anadromous marine-migrants or as smaller and younger freshwater residents. To better understand the processes influencing the expression of these phenotypes we examined the influences of growth in length (fork length) and whole body lipid content in rainbow trout (Oncorhynchus mykiss). Fish were sampled from the John Day River basin in northeast Oregon where both anadromous ("steelhead") and freshwater resident rainbow trout coexist. Larger males with higher lipid levels had a greater probability of maturing as a resident at age-1+. Among males, 38% were maturing overall, and the odds ratios of the logistic model indicated that the probability of a male maturing early as a resident at age-1+ increased 49% (95% confidence interval (CI) = 23-81%) for every 5 mm increase in length and 33% (95% CI = 10-61%) for every 0.5% increase in whole body lipid content. There was an inverse association between individual condition and water temperature as growth was greater in warmer streams while whole body lipid content was higher in cooler streams. Our results support predictions from life history theory and further suggest that relationships between individual condition, maturation, and environmental variables (e.g., water temperature) are shaped by complex developmental and evolutionary influences.

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

    Directory of Open Access Journals (Sweden)

    LAGARRIGUE T.

    2008-05-01

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

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

    Science.gov (United States)

    Woodford, Darragh J; McIntosh, Angus R

    2010-06-01

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

  2. Cle Elum Lake anadromous salmon restoration feasibility study: Summary of research, Final Report 2000

    International Nuclear Information System (INIS)

    The focus of this research was to study the feasibility for anadromous salmonids to recolonize the habitat above reservoirs in the Yakima River without disruption to irrigation withdrawals. A primary concern was whether anadromous fish could successfully exit reservoirs and survive downstream passage through the Yakima and Columbia Rivers to the ocean

  3. Cle Elum Lake Anadromous Salmon Restoration Feasibility Study: Summary of Research, 1986-1999 Progress Report.

    Energy Technology Data Exchange (ETDEWEB)

    Dey, Douglas

    2000-04-01

    The focus of this research was to study the feasibility for anadromous salmonids to recolonize the habitat above reservoirs in the Yakima River without disruption to irrigation withdrawals. A primary concern was whether anadromous fish could successfully exit reservoirs and survive downstream passage through the Yakima and Columbia Rivers to the ocean.

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

    Directory of Open Access Journals (Sweden)

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

    2012-02-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2012-01-01

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

  6. Spawning Behaviour and the Softmouth Trout Dilemma

    Directory of Open Access Journals (Sweden)

    Esteve Manu

    2014-07-01

    Full Text Available Morphological, ecological and molecular data sets do not completely agree on the phylogenetic placement of the softmouth trout, Salmo (Salmothymus obtusirostris (Heckel. Molecules posit that softmouths are closely related to brown trout, Salmo trutta L. while some morphological, ecological and life history traits place them in the most basal position of the Salmoninae subfamily between grayling (Thymallus and lenok (Brachymystax. Here we add an additional source of data, behavioural characters based on the first reported observations of softmouth spawning. During spawning softmouth females present three important behaviours not found in the other Salmo members: they continually abandon their nests, rarely staying on them for periods over nine minutes; they expel different batches of eggs at the same nest at intervals of several minutes; and they do not cover their eggs immediately after spawning. These three behaviours are intriguing for two reasons: 1 they are possible homologous to behaviours found in grayling females; 2 when coupled to the nest digging behaviour-widespread in all the salmonines, including softmouths, they seem to be mal-adaptive.

  7. Fish population and habitat analysis in Buck Creek, Washington, prior to recolonization by anadromous salmonids after the removal of Condit Dam

    Science.gov (United States)

    Allen, M. Brady; Burkhardt, Jeanette; Munz, Carrie; Connolly, Patrick J.

    2012-01-01

    We assessed the physical and biotic conditions in the part of Buck Creek, Washington, potentially accessible to anadromous fishes. This creek is a major tributary to the White Salmon River upstream of Condit Dam, which was breached in October 2011. Habitat and fish populations were characterized in four stream reaches. Reach breaks were based on stream gradient, water withdrawals, and fish barriers. Buck Creek generally was confined, with a single straight channel and low sinuosity. Boulders and cobble were the dominant stream substrate, with limited gravel available for spawning. Large-cobble riffles were 83 percent of the available fish habitat. Pools, comprising 15 percent of the surface area, mostly were formed by bedrock with little instream cover and low complexity. Instream wood averaged 6—10 pieces per 100 meters, 80 percent of which was less than 50 centimeters in diameter. Water temperature in Buck Creek rarely exceeded 16 degrees Celsius and did so for only 1 day at river kilometer (rkm) 3 and 11 days at rkm 0.2 in late July and early August 2009. The maximum temperature recorded was 17.2 degrees Celsius at rkm 0.2 on August 2, 2009. Minimum summer discharge in Buck Creek was 3.3 cubic feet per second downstream of an irrigation diversion (rkm 3.1) and 7.7 cubic feet per second at its confluence with the White Salmon River. Rainbow trout (Oncorhynchus mykiss) was the dominant fish species in all reaches. The abundance of age-1 or older rainbow trout was similar between reaches. However, in 2009 and 2010, the greatest abundance of age-0 rainbow trout (8 fish per meter) was in the most downstream reach. These analyses in Buck Creek are important for understanding the factors that may limit fish abundance and productivity, and they will help identify and prioritize potential restoration actions. The data collected constitute baseline information of pre-dam removal conditions that will allow assessment of changes in fish populations now that Condit Dam has

  8. Trout in the Classroom

    Science.gov (United States)

    Heath, Thomas

    2014-05-01

    Trout in the Classroom (TIC) is a conservation-oriented environmental education program for elementary, middle, and high school students. During the year each teacher tailors the program to fit his or her curricular needs. Therefore, each TIC program is unique. TIC has interdisciplinary applications in science, social studies, mathematics, language arts, fine arts, and physical education. In the program, students and teachers raise trout from fertilized eggs supplied by Virginia Department of Game and Inland Fisheries (VGIF) hatcheries, in aquariums equipped with special chillers designed to keep the water near 50 degrees F. The students make daily temperature measurements, and monitor pH, dissolved oxygen, conductivity, and ammonia levels. They record their data, plot trends, and make sure that the water quality is sufficient to support trout development. The fingerlings, which hatch in late October, are almost an inch and a half long by mid-January. And towards the end of the school year, students will release the fry into VGIF approved watersheds. TIC programs have been in place all across the country for more than 20 years, and are the result of numerous collaborations between teachers, volunteers, government agencies, and local organizations like Trout Unlimited. The programs were designed specifically for teachers who wanted to incorporate more environmental education into their curriculum. While the immediate goal of Trout in the Classroom is to increase student knowledge of water quality and cold water conservation, its long-term goal is to reconnect an increasingly urbanized population of youth to the system of streams, rivers, and watersheds that sustain them. Successful programs have helped: connect students to their local environments and their local watersheds; teach about watershed health and water quality, and; get students to care about fish and the environment. In Virginia, the TIC program is now in its 8th year. Over the past year, the program

  9. The Sea Trout Year 1985

    OpenAIRE

    Fahy, E

    1986-01-01

    The wet year of 1985 yielded good catches to the rod and to commercial engines. Salmon were taken in reasonable numbers in the drift nets although only small numbers of sea trout were captured by this method. The wet angling season is thought to have provided productive fishing conditions contributing largely to a 22% increase over the previous year's landings of sea trout.

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

    Science.gov (United States)

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

    2016-05-01

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

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

    Science.gov (United States)

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

    2016-05-01

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

  12. Embryotoxicity of an extract from Great Lakes lake trout to rainbow trout and lake trout

    Energy Technology Data Exchange (ETDEWEB)

    Wright, P.J.; Tillitt, D.E. [National Biological Service, Columbia, MO (United States). Midwest Science Center

    1995-12-31

    Aquatic ecosystems such as the Great Lakes are known to be contaminated with chemicals that are toxic to fish. However, the role of these contaminants in reproductive failures of fishes, such as lake trout recruitment, has remained controvertible. It was the objective to evaluate dioxin-like embryotoxicity of a complex mixture of chemicals and predict their potential to cause the lack of recruitment in Great Lakes lake trout. Graded doses of a complex environmental extract were injected into eggs of both rainbow trout and lake trout. The extract was obtained from whole adult lake trout collected from Lake Michigan in 1988. The extract was embryotoxic in rainbow trout, with LD50 values for Arlee strain and Erwin strain of 33 eggEQ and 14 eggEQ respectively. The LOAEL for hemorrhaging, yolk-sac edema, and craniofacial deformities in rainbow trout were 2, 2, and 4 eggEQ, respectively. Subsequent injections of the extract into lake trout eggs were likewise embryotoxic, with an LD50 value of 7 eggEQ. The LOAEL values for the extract in lake trout for hemorrhaging, yolk-sac edema, and craniofacial deformities were 0.1, 1, and 2 eggEQ, respectively. The current levels of contaminants in lake trout eggs are above the threshold for hemorrhaging and yolk-sac edema. The results also support the use of an additive model of toxicity to quantify PCDDs, PCDFs, Non-o-PCBs, and Mono-o-PCBs in relation to early life stage mortality in Lake Michigan lake trout.

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

    Directory of Open Access Journals (Sweden)

    TEIXEIRA A.

    2006-04-01

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

  14. Plump Cutthroat Trout and Thin Rainbow Trout in a Lentic Ecosystem

    OpenAIRE

    Courtney, Joshua; Abbott, Jessica; Schmidt, Kerri; Courtney, Michael

    2012-01-01

    Background: Much has been written about introduced rainbow trout (Oncorhynchus mykiss) interbreeding and outcompeting cutthroat trout (Oncorhynchus clarkii). However, the specific mechanisms by which rainbow trout and their hybrids outcompete cutthroat trout have not been thoroughly explored, and the published data is limited to lotic ecosystems. Materials and Methods: Samples of rainbow trout and cutthroat trout were obtained from a lentic ecosystem by angling. The total length and weight of...

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

    OpenAIRE

    Korsu, K. (Kai)

    2008-01-01

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

  16. 50 CFR 224.101 - Enumeration of endangered marine and anadromous species.

    Science.gov (United States)

    2010-10-01

    ... the following: (a) Marine and anadromous fish. The following table lists the common and scientific... (Balaena mysticetus); Chinese river dolphin (Lipotes vexillifer); Cochito (Phocoena sinus); Fin or finback... novaeangliae); Indus River dolphin (Platanista minor); Mediterranean monk seal (Monachus monachus);...

  17. 76 FR 57717 - Endangered and Threatened Species; Take of Anadromous Fish

    Science.gov (United States)

    2011-09-16

    ... Anadromous Fish AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric... Salmonid Tissue Archive to UC Davis, for purposes of genetic investigation. The archived collection... microsatellite and single nucleotide polymorphism (SNPs) markers, to study genetic relationships associated...

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

    DEFF Research Database (Denmark)

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

    2001-01-01

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

  19. Estrogenic effects of phytoestrogens in brown trout (Salmo trutta)

    DEFF Research Database (Denmark)

    Nielsen, Louise Marie; Holbech, Henrik; Bjerregaard, Poul;

    2010-01-01

    Phytoestrogens produced by agriculturally important crops such as clover, alfalfa and soya have the potential of leaching from the soil into streams. Concentrations of phytoestrogens in freshwater systems ranging from the low nanogram to low microgram per litre range have been demonstrated. However...

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

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Greg

    2000-11-28

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

  1. Coeur d'Alene Tribe Fish, Water and Wildlife Program : Coeur d'Alene Tribe Trout Production Facility Master Plan.

    Energy Technology Data Exchange (ETDEWEB)

    Peters, Ronald L.; Woodward-Lilengreen, Kelly L.; Vitale, Angelo J.

    1999-09-01

    The Northwest Power Planning Council (Council) receives and reviews proposals to mitigate for fish and wildlife losses and refers approved measures to Bonneville Power Administration (BPA) for funding. The Northwest Power Act (Act) calls on the Council to include measures in its Columbia River Basin Fish and Wildlife Program (Program) to address system-wide fish and wildlife losses. The Act further states that the Council may include in its Program measures that provide off-site mitigation--mitigation physically removed from the hydro project(s) that caused the need to mitigate. The Program includes a goal ''to recover and preserve the health of native resident fish injured by the hydropower system, where feasible, and, where appropriate, to use resident fish to mitigate for anadromous fish losses in the system.'' Among those recommended measures are off-site mitigation for losses of anadromous fisheries including the measure under analysis in this Coeur d'Alene Tribe Trout Production Facility Master Plan, proposed by the Coeur d'Alene Tribe. To meet the need for off-site mitigation for anadromous fish losses in the Columbia River Basin in a manner consistent with the objectives of the Council's Fish and Wildlife Program, the Coeur d'Alene Tribe is proposing that the BPA fund the design, construction, operations and maintenance of a trout production facility on the Coeur d'Alene Indian Reservation. Measures for establishing a Coeur d'Alene fish production facility have been a part of the Council's Program since 1987. The Coeur d'Alene Tribe Trout Production Facility is intended to rear and release westslope cutthroat trout into rivers and streams with the express purpose of increasing the numbers of fish spawning, incubating and rearing in the natural environment. It will use the modern technology that hatcheries offer to overcome the mortality resulting from habitat degradation in lakes, rivers, and

  2. Do Rainbow Trout and Their Hybrids Outcompete Cutthroat Trout in a Lentic Ecosystem?

    OpenAIRE

    Courtney, Joshua M.; Courtney, Amy C.; Courtney, Michael W.

    2013-01-01

    Much has been written about introduced rainbow trout interbreeding and outcompeting native cutthroat trout. However, specific mechanisms have not been thoroughly explored, and most data is limited to lotic ecosystems. Samples of Snake River cutthroat trout (Oncorhynchus clarkii bouvieri), the rainbow-cutthroat hybrid, the cutbow trout (Onchorhynchus mykiss x clarkii), and rainbow trout (Oncorhynchus mykiss), were obtained from a lentic ecosystem (Eleven Mile Reservoir, Colorado) by creel surv...

  3. Contribution of anadromous fish to the diet of European catfish in a large river system

    Science.gov (United States)

    Syväranta, Jari; Cucherousset, Julien; Kopp, Dorothée; Martino, Aurélia; Céréghino, Régis; Santoul, Frédéric

    2009-05-01

    Many anadromous fish species, when migrating from the sea to spawn in fresh waters, can potentially be a valuable prey for larger predatory fish, thereby efficiently linking these two ecosystems. Here, we assess the contribution of anadromous fish to the diet of European catfish ( Silurus glanis) in a large river system (Garonne, southwestern France) using stable isotope analysis and allis shad ( Alosa alosa) as an example of anadromous fish. Allis shad caught in the Garonne had a very distinct marine δ13C value, over 8‰ higher after lipid extraction compared to the mean δ13C value of all other potential freshwater prey fish. The δ13C values of European catfish varied considerably between these two extremes and some individuals were clearly specializing on freshwater prey, whereas others specialized on anadromous fish. The mean contribution of anadromous fish to the entire European catfish population was estimated to be between 53% and 65%, depending on the fractionation factor used for δ13C.

  4. Habitat Quality and Anadromous Fish Production on the Warm Springs Reservation. Final Report.

    Energy Technology Data Exchange (ETDEWEB)

    Fritsch, Mark A.

    1995-06-01

    The number of anadromous fish returning to the Columbia River and its tributaries has declined sharply in recent years. Changes in their freshwater, estuarine, and ocean environments and harvest have all contributed to declining runs of anadromous fish. Restoration of aquatic resources is of paramount importance to the Confederated Tribes of the Warm Springs (CTWS) Reservation of Oregon. Watersheds on the Warm Springs Reservation provide spawning and rearing habitat for several indigenous species of resident and anadromous fish. These streams are the only ones in the Deschutes River basin that still sustain runs of wild spring chinook salmon, Oncorhynchus, tshawytscha. Historically, reservation streams supplied over 169 km of anadromous fish habitat. Because of changes in flows, there are now only 128 km of habitat that can be used on the reservation. In 1981, the CTWS began a long-range, 3-phase study of existing and potential fish resources on the reservation. The project, consistent with the Northwest Power Planning Council`s Fish and Wildlife Program, was designed to increase the natural production of anadromous salmonids on the reservation.

  5. Habitat quality and anadromous fish production on the Warm Springs Reservation. Final report

    International Nuclear Information System (INIS)

    The number of anadromous fish returning to the Columbia River and its tributaries has declined sharply in recent years. Changes in their freshwater, estuarine, and ocean environments and harvest have all contributed to declining runs of anadromous fish. Restoration of aquatic resources is of paramount importance to the Confederated Tribes of the Warm Springs (CTWS) Reservation of Oregon. Watersheds on the Warm Springs Reservation provide spawning and rearing habitat for several indigenous species of resident and anadromous fish. These streams are the only ones in the Deschutes River basin that still sustain runs of wild spring chinook salmon, Oncorhynchus, tshawytscha. Historically, reservation streams supplied over 169 km of anadromous fish habitat. Because of changes in flows, there are now only 128 km of habitat that can be used on the reservation. In 1981, the CTWS began a long-range, 3-phase study of existing and potential fish resources on the reservation. The project, consistent with the Northwest Power Planning Council's Fish and Wildlife Program, was designed to increase the natural production of anadromous salmonids on the reservation

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

    Science.gov (United States)

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

    2011-01-01

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

  7. 33 CFR 117.337 - Trout River.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Trout River. 117.337 Section 117... OPERATION REGULATIONS Specific Requirements Florida § 117.337 Trout River. The draw of the CSX Railroad Bridge across the Trout River, mile 0.9 at Jacksonville, operates as follows: (a) The bridge is...

  8. Evaluation of Bull Trout Movements in the Tucannon and Lower Snake Rivers, 2002-2006 Project Completion Summary.

    Energy Technology Data Exchange (ETDEWEB)

    Faler, Michael P. [U.S. Fish and Wildlife Service; Mendel, Glen; Fulton, Carl [Washington Department of Fish and Wildlife

    2008-11-20

    was small (n=6). In spite of this project's shortcomings, bull trout continue to be observed in low numbers at Snake River dam fish facilities. It is highly possible that bull trout observed at the Snake River dam fish facilities are originating from sources other than the Tucannon River. We suggest that these fish might come from upstream sources like the Clearwater or Salmon rivers in Idaho, and are simply following the outmigration of juvenile anadromous fish (a food supply) as they emigrate toward the Pacific Ocean. Based on our study results, we recommend abandoning radio telemetry as a tool to monitor bull trout movements in the mainstem Snake River. We do recommend continuing PIT tagging and tag interrogation activities to help determine the origin of bull trout using the Snake River hydropower facilities. As a complementary approach, we also suggest the use of genetic assignment tests to help determine the origin of these fish. Lastly, several recommendations are included in the report to help manage and recover bull trout in the Tucannon subbasin.

  9. Reprodctive biology of trout in a thermally enriched environment: the Firehole River of Yellowstone National Park. Second annual progress report, April 1, 1974--June 30, 1976

    International Nuclear Information System (INIS)

    Temperature recordings indicate that trout inhabiting the warmest section of the river live at temperatures averaging 11.5 C higher than those inhabiting the upstream, cold-water section above most of the thermal discharges. Daily maximum temperatures during summer occasionally exceed published lethal levels for trout, and daily means consistently exceed the 200C upper limit considered favorable for growth. Brown trout at the cold-water station show a normal reproductive pattern and spawn in the late fall. Brown trout at the warmest water station show a similar seasonal pattern; however about half of the specimens examined were either not maturing or were undergoing massive atresia of ova. Rainbow trout also have a similar reproductive pattern and spawn in late fall, in contrast to the normal spring and early summer spawning period of this species. Both species grow considerably faster at the warm-water stations than they do at the cold-water stations, despite having their growth inhibited by high summer temperatures. Differences in diet are evident. Trout captured from both warm and cold areas have internal body temperatures closely similar to water temperatures, and thus provide no evidence for the existence of cooler microhabitats within the general stream

  10. A STUDY ON TROUT BREEDING IN DUZCE PROVINCE

    OpenAIRE

    Akbulut, Süleyman; KETEN, Akif

    2009-01-01

    In this study, trout breeding facilities of Duzce Province, a suitable place for trout breeding, were evaluated. As a result of this evaluation, current status, capacities, and problems of trout breeding facilities were determined. Some suggestions were provided to solve these problems and increase the capacity of trout breeding facilities. Keywords: Duzce, Trout Breeding.

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

    Science.gov (United States)

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

    2006-01-01

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

  12. [Human brown adipose tissue].

    Science.gov (United States)

    Virtanen, Kirsi A; Nuutila, Pirjo

    2015-01-01

    Adult humans have heat-producing and energy-consuming brown adipose tissue in the clavicular region of the neck. There are two types of brown adipose cells, the so-called classic and beige adipose cells. Brown adipose cells produce heat by means of uncoupler protein 1 (UCP1) from fatty acids and sugar. By applying positron emission tomography (PET) measuring the utilization of sugar, the metabolism of brown fat has been shown to multiply in the cold, presumably influencing energy consumption. Active brown fat is most likely present in young adults, persons of normal weight and women, least likely in obese persons.

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

    Science.gov (United States)

    George, Scott D.; Baldigo, Barry P.

    2016-05-13

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

  14. Atmospheres of Brown Dwarfs

    CERN Document Server

    Helling, Christiane

    2014-01-01

    Brown Dwarfs are the coolest class of stellar objects known to date. Our present perception is that Brown Dwarfs follow the principles of star formation, and that Brown Dwarfs share many characteristics with planets. Being the darkest and lowest mass stars known makes Brown Dwarfs also the coolest stars known. This has profound implication for their spectral fingerprints. Brown Dwarfs cover a range of effective temperatures which cause brown dwarfs atmospheres to be a sequence that gradually changes from a M-dwarf-like spectrum into a planet-like spectrum. This further implies that below an effective temperature of < 2800K, clouds form already in atmospheres of objects marking the boundary between M-Dwarfs and brown dwarfs. Recent developments have sparked the interest in plasma processes in such very cool atmospheres: sporadic and quiescent radio emission has been observed in combination with decaying Xray-activity indicators across the fully convective boundary.

  15. 75 FR 76400 - Endangered and Threatened Species; Take of Anadromous Fish

    Science.gov (United States)

    2010-12-08

    ... Anadromous Fish AGENCY: National Marine Fisheries Service, National Oceanic and Atmospheric Administration... analysis as part of Project 3, in Pescadero Lagoon. Project 1 is a study on the summer ecology of juvenile... significance of estuary rearing on the timing of ocean entry. Project 3 is a study on the ecology of...

  16. Endocrine systems in juvenile anadromous and landlocked Atlantic salmon (Salmo salar): Seasonal development and seawater acclimation

    DEFF Research Database (Denmark)

    Nilsen, Tom O; Ebbesson, Lars O E; Kiilerich, Pia;

    2008-01-01

    The present study compares developmental changes in plasma levels of growth hormone (GH), insulin-like growth factor I (IGF-I) and cortisol, and mRNA levels of their receptors and the prolactin receptor (PRLR) in the gill of anadromous and landlocked Atlantic salmon during the spring parr-smolt t...

  17. 78 FR 74116 - Endangered and Threatened Species; Take of Anadromous Fish

    Science.gov (United States)

    2013-12-10

    ... Anadromous Fish AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric... the form of Hatchery and Genetic Management Plans (HGMPs), pursuant to the Endangered Species Act of...: Written responses to the application should be sent to Craig Busack, National Marine Fisheries...

  18. 78 FR 31518 - Endangered and Threatened Species; Take of Anadromous Fish

    Science.gov (United States)

    2013-05-24

    ... Anadromous Fish AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric... Genetic Management Plans (HGMPs), pursuant to the Endangered Species Act of 1973, as amended (ESA). The... the draft environmental assessment should be sent to Brett Farman, National Marine Fisheries...

  19. 77 FR 75611 - Endangered and Threatened Species; Take of Anadromous Fish

    Science.gov (United States)

    2012-12-21

    ... Anadromous Fish AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric... Hatchery and Genetic Management Plans (HGMPs), submitted by the Lower Elwha Klallam Tribe and the... salmon and steelhead. The programs would continue to be operated to minimize any impacts on...

  20. 77 FR 34349 - Endangered and Threatened Species; Take of Anadromous Fish

    Science.gov (United States)

    2012-06-11

    ... Anadromous Fish AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric..., the National Marine Fisheries Service (NMFS) announced the availability for public review of four Hatchery and Genetic Management Plans (HGMPs) submitted by the Oregon Department of Fish and Wildlife...

  1. Lake Roosevelt Rainbow Trout Habitat/Passage Improvement Project, Annual Report 2002-2003.

    Energy Technology Data Exchange (ETDEWEB)

    Sears, Sheryl

    2004-01-01

    The construction of Chief Joseph and Grand Coulee Dams completely and irrevocably blocked anadromous fish migrations to the Upper Columbia River. Historically this area hosted vast numbers of salmon returning to their natal waters to reproduce and die. For the native peoples of the region, salmon and steelhead were a principle food source, providing physical nourishment and spiritual sustenance, and contributing to the religious practices and the cultural basis of tribal communities. The decaying remains of spawned-out salmon carcasses contributed untold amounts of nutrients into the aquatic, aerial, and terrestrial ecosystems of tributary habitats in the upper basin. Near the present site of Kettle Falls, Washington, the second largest Indian fishery in the state existed for thousands of years. Returning salmon were caught in nets and baskets or speared on their migration to the headwater of the Columbia River in British Columbia. Catch estimates at Kettle Falls range from 600,000 in 1940 to two (2) million around the turn of the century (UCUT, Report No.2). The loss of anadromous fish limited the opportunities for fisheries management and enhancement exclusively to those actions addressed to resident fish. The Lake Roosevelt Rainbow Trout Habitat/Passage Improvement Project is a mitigation project intended to enhance resident fish populations and to partially mitigate for anadromous fish losses caused by hydropower system impacts. This substitution of resident fish for anadromous fish losses is considered in-place and out-of-kind mitigation. Upstream migration and passage barriers limit the amount of spawning and rearing habitat that might otherwise be utilized by rainbow trout. The results of even limited stream surveys and habitat inventories indicated that a potential for increased natural production exists. However, the lack of any comprehensive enhancement measures prompted the Upper Columbia United Tribes Fisheries Center (UCUT), Colville Confederated

  2. Lake Roosevelt Rainbow Trout Habitat/Passage Improvement Project, Annual Report 2001-2002.

    Energy Technology Data Exchange (ETDEWEB)

    Sears, Sheryl

    2003-01-01

    The construction of Chief Joseph and Grand Coulee Dams completely and irrevocably blocked anadromous fish migrations to the Upper Columbia River. Historically this area hosted vast numbers of salmon returning to their natal waters to reproduce and die. For the native peoples of the region, salmon and steelhead were a principle food source, providing physical nourishment and spiritual sustenance, and contributing to the religious practices and the cultural basis of tribal communities. The decaying remains of spawned-out salmon carcasses contributed untold amounts of nutrients into the aquatic, aerial, and terrestrial ecosystems of tributary habitats in the upper basin. Near the present site of Kettle Falls, Washington, the second largest Indian fishery in the state existed for thousands of years. Returning salmon were caught in nets and baskets or speared on their migration to the headwater of the Columbia River in British Columbia. Catch estimates at Kettle Falls range from 600,000 in 1940 to two (2) million around the turn of the century (UCUT, Report No.2). The loss of anadromous fish limited the opportunities for fisheries management and enhancement exclusively to those actions addressed to resident fish. The Lake Roosevelt Rainbow Trout Habitat/Passage Improvement Project is a mitigation project intended to enhance resident fish populations and to partially mitigate for anadromous fish losses caused by hydropower system impacts. This substitution of resident fish for anadromous fish losses is considered in-place and out-of-kind mitigation. Upstream migration and passage barriers limit the amount of spawning and rearing habitat that might otherwise be utilized by rainbow trout. The results of even limited stream surveys and habitat inventories indicated that a potential for increased natural production exists. However, the lack of any comprehensive enhancement measures prompted the Upper Columbia United Tribes Fisheries Center (UCUT), Colville Confederated

  3. Genomic population structure of freshwater-resident and anadromous ide (Leuciscus idus) in north-western Europe

    DEFF Research Database (Denmark)

    Skovrind, Mikkel; Olsen, Morten Tange; Vieira, Filipe Garrett;

    2016-01-01

    to become increasingly affected by changes in salinity is the ide (Leuciscus idus). The ide is a stenohaline freshwater fish that primarily inhabits rivers, with frequent anadromous behavior when sea salinity does not exceed 15%. Unlike most other anadromous Baltic Sea fish species, the ide has yet...... species. In addition to providing a first insight into the population structure of north-western European ide, our data also (1) provide indications of a single illegal introduction by man; (2) suggest limited genetic effects of heavy pollution in the past; and (3) indicate possible historical anadromous...

  4. Copper uptake across rainbow trout gills: mechanisms of apical entry

    DEFF Research Database (Denmark)

    Grosell, Martin Hautopp; Wood, C. M.

    2002-01-01

    Copper, Homeostasis, sodium uptake, copper/sodium interactions, gill, rainbow trout, Oncorhynchus mykiss......Copper, Homeostasis, sodium uptake, copper/sodium interactions, gill, rainbow trout, Oncorhynchus mykiss...

  5. A blood chemistry profile for lake trout

    Science.gov (United States)

    Edsall, Carol Cotant

    1999-01-01

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

  6. Study of Some Morphological Characters of Three Trout Breed Farmed in Salmonid Exploitations from Moldova

    Directory of Open Access Journals (Sweden)

    Cătălin Emilian Nistor

    2014-05-01

    Full Text Available Study of morphological characters at fish by means of biometry is a frequently utilized method and consists in determining the variability of characters in groups of individuals, by direct measurement, weighting and statistical processing of obtained data.Effectuation of body measurements and weighting is used to determine the increase in length of fish and to evaluate the general physiological condition. Brook trout, rainbow trout, and brown trout were the object of the current study by analyzing of 50 individuals, 10 individuals in each batch (F1, F2, C1 C2 and I1, from two trout farms from Moldova. After processing the obtained data were calculated the most representative indexes and maintenance coefficients. The obtained values were between 3.49 at batch F1 and 3.94 at batch I1 for profile index; 1.5 at batch I1 and 1.75 at batch F1 for Fulton coefficient; 1.47 at batch F2 and 1.6 at batch I1 for Kiselev index; 41.36 for batch F1 and 47.94 at batch C2 for thickness index; 19.94 C1 batch and 22.08 at F1 batch for fleshy index I, and 19.05 C2 batch and 21.2 at I1 batch for fleshy index II. Having in view the obtained results we can conclude that the analyzed fishes had a good state of maintenance.

  7. Brown Fat Cell Isolation

    OpenAIRE

    sprotocols

    2014-01-01

    Author: C.R. Kahn ### 1.) ISOLATION AND PRIMARY CULTURE OF BROWN FAT PREADIPOCYTES ### Rationale: To prepare primary brown preadipocytes for immortalization: useful for metabolic studies from knockout mice. This consists of the following five protocols. References: Fasshauer, M., J. Klein, K M. Kriauciunas, K. Ueki, M.Benito, and C.R. Kahn. 2001. Essential role of insulin substrate 1 in differentiation of brown adipocytes. *Mol Cell Biol* 21: 319-329. Fasshauer, M....

  8. [Content of Thyroid and Sex Steroid Hormones in Young-of-the-Year of Black Sea Trout Salmo trutta labrax from Two Spatial Groups for Different Duration of Starvation].

    Science.gov (United States)

    Pavlov, D S; Pavlov, E D; Ganzha, E V; Kostin, V V

    2015-01-01

    The content of thyroid and sex steroid hormones is determined in fish-farm juveniles of Black Sea trout 5.5 months old, from the bottom and pelagic spatial groups differing in the probability of future selection of the resident or anadromous life strategies, respectively. Differences in the concentration of the aforementioned hormones are found in young-of-the-year corresponding to those in the migratory and resident forms of yearlings of trout. In the juveniles from the pelagic group at the age 0+, the level of triiodothyronine, thyroxine, and testosterone is higher than in specimens from the bottom group. Prolonged starvation results in a higher content of triiodthyronine, thyroxine, and testosterone in the blood of juveniles from both spatial groups. The concentration of estradiol-17β increases in pelagic specimens and decreases in bottom specimens.

  9. Endocrine systems in juvenile anadromous and landlocked Atlantic salmon (Salmo salar): Seasonal development and seawater acclimation

    Science.gov (United States)

    Nilsen, Tom O.; Ebbesson, Lars O.E.; Kiilerich, P.; Bjornsson, B. Th; Madsen, Steffen S.; McCormick, S.D.; Stefansson, S.O.

    2008-01-01

    The present study compares developmental changes in plasma levels of growth hormone (GH), insulin-like growth factor I (IGF-I) and cortisol, and mRNA levels of their receptors and the prolactin receptor (PRLR) in the gill of anadromous and landlocked Atlantic salmon during the spring parr-smolt transformation (smoltification) period and following four days and one month seawater (SW) acclimation. Plasma GH and gill GH receptor (GHR) mRNA levels increased continuously during the spring smoltification period in the anadromous, but not in landlocked salmon. There were no differences in plasma IGF-I levels between strains, or any increase during smoltification. Gill IGF-I and IGF-I receptor (IGF-IR) mRNA levels increased in anadromous salmon during smoltification, with no changes observed in landlocked fish. Gill PRLR mRNA levels remained stable in both strains during spring. Plasma cortisol levels in anadromous salmon increased 5-fold in May and June, but not in landlocked salmon. Gill glucocorticoid receptor (GR) mRNA levels were elevated in both strains at the time of peak smoltification in anadromous salmon, while mineralocorticoid receptor (MR) mRNA levels remained stable. Only anadromous salmon showed an increase of gill 11??-hydroxysteroid dehydrogenase type-2 (11??-HSD2) mRNA levels in May. GH and gill GHR mRNA levels increased in both strains following four days of SW exposure in mid-May, whereas only the anadromous salmon displayed elevated plasma GH and GHR mRNA after one month in SW. Plasma IGF-I increased after four days in SW in both strains, decreasing in both strains after one month in SW. Gill IGF-I mRNA levels were only increased in landlocked salmon after 4 days in SW. Gill IGF-IR mRNA levels in SW did not differ from FW levels in either strain. Gill PRLR mRNA did not change after four days of SW exposure, and decreased in both strains after one month in SW. Plasma cortisol levels did not change following SW exposure in either strain. Gill GR, 11

  10. Wildlife risks associated with passage of contaminated, anadromous fish at Federal Energy Regulatory Commission Licensed Dams in Michigan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The purpose of this paper is to assess the issue of anadromous fish passage at Federal Energy Regulatory Commission (FERC) licensed hydropower dams in Michigan and...

  11. Improved husbandry to control an outbreak of rainbow trout fry syndrome caused by infection with Flavobacterium psychrophilum

    Science.gov (United States)

    Bebak, J.A.; Welch, T.J.; Starliper, C.E.; Baya, A.M.; Garner, M.M.

    2007-01-01

    Case Description - A cohort of 35,200, 13-week-old, female rainbow trout at a fish farm was evaluated because of a 2-week history of anorexia and lethargy and a mortality rate of approximately 100 fish/d. Clinical Findings - Affected fish were lethargic and thin and had disequilibrium, bilateral exophthalmia, pale red gills and kidneys, red-tinged coelomic fluid, and pale brown livers. Some fish were differentially pigmented bilaterally. The presumptive diagnosis was bacterial or viral septicemia. The definitive diagnosis was rainbow trout fry syndrome caused by infection with Flavobacterium psychrophilum. Treatment and Outcome - A strategy for controlling the outbreak based on reducing pathogen numbers in affected tanks and reducing pathogen spread among tanks was developed. The option of treating with antimicrobial-medicated feed was discussed with the farmer, but was declined. After changes were made, mortality rate declined quickly, with no more deaths within 10 days after the initial farm visit. Clinical Relevance - Bacterial coldwater disease is the most common manifestation of infection with F psychrophilum in fingerling and adult rainbow trout. However, the organism can also cause rainbow trout fry syndrome. This condition should be included on a list of differential diagnoses for septicemia in hatchery-reared rainbow trout fry.

  12. Restoring Anadromous Fish Habitat in Big Canyon Creek Watershed; Anadromous Fish Habitat Restoration in the Nichols Canyon Subwatershed, 2000 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Koziol, Deb (Nez Perce Soil and Water Conservation District, Lewiston, ID)

    2001-02-01

    Nez Perce Soil & Water Conservation District (NPSWCD) undertook the Nichols Canyon Subwatershed Steelhead Trout Habitat Improvement Project in the spring of 1999 with funding from a grant through the Bonneville Power Administration. The Project's purpose is to install and implement agricultural best management practices (MBPS) and riparian restorations with the goal of improving steelhead trout spawning and rearing habitat in the subwatershed. Improvements to fish habitat in the Big Canyon Creek tributaries enhances natural production of the species in Big Canyon Creek and ultimately the Clearwater River. This report is a summation of the progress made by the NPSWCD in the Project's second year.

  13. Patterns of hybridization among cutthroat trout and rainbow trout in northern Rocky Mountain streams.

    Science.gov (United States)

    McKelvey, Kevin S; Young, Michael K; Wilcox, Taylor M; Bingham, Daniel M; Pilgrim, Kristine L; Schwartz, Michael K

    2016-02-01

    Introgressive hybridization between native and introduced species is a growing conservation concern. For native cutthroat trout and introduced rainbow trout in western North America, this process is thought to lead to the formation of hybrid swarms and the loss of monophyletic evolutionary lineages. Previous studies of this phenomenon, however, indicated that hybrid swarms were rare except when native and introduced forms of cutthroat trout co-occurred. We used a panel of 86 diagnostic, single nucleotide polymorphisms to evaluate the genetic composition of 3865 fish captured in 188 locations on 129 streams distributed across western Montana and northern Idaho. Although introgression was common and only 37% of the sites were occupied solely by parental westslope cutthroat trout, levels of hybridization were generally low. Of the 188 sites sampled, 73% contained ≤5% rainbow trout alleles and 58% had ≤1% rainbow trout alleles. Overall, 72% of specimens were nonadmixed westslope cutthroat trout, and an additional 3.5% were nonadmixed rainbow trout. Samples from seven sites met our criteria for hybrid swarms, that is, an absence of nonadmixed individuals and a random distribution of alleles within the sample; most (6/7) were associated with introgression by Yellowstone cutthroat trout. In streams with multiple sites, upstream locations exhibited less introgression than downstream locations. We conclude that although the widespread introduction of nonnative trout within the historical range of westslope cutthroat trout has increased the incidence of introgression, sites containing nonadmixed populations of this taxon are common and broadly distributed.

  14. Father Brown, Selected sories

    NARCIS (Netherlands)

    Chesterton, G.K.

    2005-01-01

    Father Brown, a small, round Catholic priest with a remarkable understanding of the criminal mind, is one of literature's most unusual and endearing detectives, able to solve the strangest crimes in a most fascinating manner. This collection draws from all five Father Brown books, and within their r

  15. Rainbow Trout Innate Immunity against Flavobacterium psychrophilum

    Science.gov (United States)

    Flavobacterium psychrophilum infection is associated with significant loss of rainbow trout production in the U.S. and other parts of the world. In 2005, a selective breeding program was initiated at the National Center for Cool and Cold Water Aquaculture to improve rainbow trout innate resistance ...

  16. Farming of Freshwater Rainbow Trout in Denmark

    DEFF Research Database (Denmark)

    Jokumsen, Alfred; Svendsen, Lars Moeslund

    Textbook on Farming of Freshwater Rainbow Trout in Denmark. Danish edition with the title: Opdræt af regnbueørred i Danmark......Textbook on Farming of Freshwater Rainbow Trout in Denmark. Danish edition with the title: Opdræt af regnbueørred i Danmark...

  17. Bath vaccination of rainbow trout against yersiniosis

    DEFF Research Database (Denmark)

    Raida, Martin Kristian; Buchmann, Kurt

    2007-01-01

    Studies have been conducted on the temperature-dependent effect of bath vaccination of rainbow trout against Yersinia ruckeri O1. Protection of rainbow trout fry against challenge, following bath vaccination with a bacterin of Yersinia ruckeri O1, the bacterial pathogen causing enteric red mouth...... disease (ERM), was investigated at 5, 15 and 25° C. Rainbow trout fry were kept at controlled temperatures for two month before they were immersed in a commercial Yersinia ruckeri O1 bacterin for 10 minutes. Control groups were sham vaccinated using pure water. Fish were challenged with Yersinia ruckeri O......1 one and two month post vaccination at the three temperatures. Protection of vaccinated fish was seen one and two month post vaccination in rainbow trout reared at 15° C. There was no effect of vaccination in rainbow trout reared at 5 and 25° C. Spleen tissue was sampled from 5 vaccinated and 5...

  18. Patterns of hybridization among cutthroat trout and rainbow trout in northern Rocky Mountain streams

    OpenAIRE

    McKelvey, Kevin S.; Young, Michael K.; Taylor M Wilcox; Bingham, Daniel M.; Pilgrim, Kristine L.; Schwartz, Michael K.

    2016-01-01

    Abstract Introgressive hybridization between native and introduced species is a growing conservation concern. For native cutthroat trout and introduced rainbow trout in western North America, this process is thought to lead to the formation of hybrid swarms and the loss of monophyletic evolutionary lineages. Previous studies of this phenomenon, however, indicated that hybrid swarms were rare except when native and introduced forms of cutthroat trout co‐occurred. We used a panel of 86 diagnost...

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

    Science.gov (United States)

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

    2015-10-09

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

  20. Hydrography - Class A Wild Trout Streams - points

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Class A streams are streams that support a population of wild (natural reproduction) trout of sufficient size and abundance to support a long-term and rewarding...

  1. Hydrography - Class A Wild Trout Streams

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Class A streams are streams that support a population of wild (natural reproduction) trout of sufficient size and abundance to support a long-term and rewarding...

  2. A Vegetation Survey of Trout Brook Flowage

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Trout Brook structure was started in 1963 under the Accelerated Public Works Program and finished in the summer of 1965. There is a 200 foot earthdike, a metal...

  3. Longevity of Lake Superior lake trout

    Science.gov (United States)

    Schram, Stephen T.; Fabrizio, Mary C.

    1998-01-01

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

  4. Bull trout in the Boundary System: managing connectivity and the feasibility of a reintroduction in the lower Pend Oreille River, northeastern Washington

    Science.gov (United States)

    Dunham, Jason B.; Taylor, Eric B.; Allendorf, Fred W.

    2014-01-01

    Many of the World’s rivers are influenced by large dams (>15 m high) most of which have fragmented formerly continuous habitats, and significantly altered fish passage, natural flow, temperature, and sediment fluxes (Nilsson and others, 2005; Arthington, 2012; Liermann and others, 2012). In the Pacific Northwest, dams on major rivers have been a major focus for fishery managers, primarily in regard to passage of anadromous salmonids (principally Pacific salmon and steelhead trout [Oncorhynchus mykiss], for example, Ferguson and others, 2011), but more recently other species, such as Pacific lamprey (Entosphenus tridentatus) and resident (non-anadromous) salmonids, are receiving more attention (Neraas and Spruell, 2001; Moser and others, 2002; Muhlfeld and others, 2012). In the case of resident salmonids, fish can adopt a wide range of migratory behaviors that often bring them into mainstem rivers where they can come into direct contact with large dams. When this occurs, some of the most important direct effects of dams on salmonids include barriers to upstream and downstream movement and mortality associated with entrainment within the dam or spill over dams. Biologically, these direct impacts can lead to (1) disruption of natural historical (pre-dam) genetic and demographic connectivity among local populations, (2) loss of access to historically used migratory destinations, (3) loss of individuals to the population through mortality associated with entrainment.

  5. Irradiated brown dwarfs

    CERN Document Server

    Casewell, S L; Lawrie, K A; Maxted, P F L; Dobbie, P D; Napiwotzki, R

    2014-01-01

    We have observed the post common envelope binary WD0137-349 in the near infrared $J$, $H$ and $K$ bands and have determined that the photometry varies on the system period (116 min). The amplitude of the variability increases with increasing wavelength, indicating that the brown dwarf in the system is likely being irradiated by its 16500 K white dwarf companion. The effect of the (primarily) UV irradiation on the brown dwarf atmosphere is unknown, but it is possible that stratospheric hazes are formed. It is also possible that the brown dwarf (an L-T transition object) itself is variable due to patchy cloud cover. Both these scenarios are discussed, and suggestions for further study are made.

  6. Bull Trout Spawning Surveys: Kootenai National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Bull trout are listed as threatened under the Endangered Species Act and Myrtle Creek was designated as critical habitat for bull trout this year. Myrtle Creek...

  7. Integrated Hatchery Operations Team: Policies and Procedures for Columbia Basin Anadromous Salmonid Hatcheries, 1994 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Integrated Hatchery Operations Team (Northwest Power Planning Council, Portland, OR)

    1995-01-01

    This document outlines regional policies and procedures for hatchery operations in the Columbia River Basin. The purpose of these policies is to provide regional guidelines by which all anadromous fish hatcheries will be operated. These policies will be adopted by the fisheries co-managers, and will provide guidance to operate hatcheries in an efficient and biologically sound manner. The hatchery policies presented in this manual are not intended to establish production priorities. Rather, the intent is to guide hatchery operations once production numbers are established. Hatchery operations discussed in this report include broodstock collection, spawning, incubation of eggs, fish rearing and feeding, fish release, equipment maintenance and operations, and personnel training. Decisions regarding production priorities must be provided by fishery managers through a comprehensive plan that addresses both natural and hatchery fish production. The Integrated Hatchery Operations Team is a multi-agency group called for by the Northwest Power Planning Council. This team was directed to develop new basinwide policies for managing and operating all existing and future anadromous fish hatcheries in the Columbia River Basin. The parties pledge to confer with each other and to use their authorities and resources to accomplish these mutually acceptable hatchery practices.

  8. Evaluation and Monitoring of Idaho Habitat Enhancement and Anadromous Fish Natural Production : Annual Report 1986.

    Energy Technology Data Exchange (ETDEWEB)

    Petrosky, Charles E.; Holubetz, Terry B.

    1987-11-01

    The Idaho Department of Fish and Game (IDFG) has been conducting an evaluation of existing and proposed habitat improvement projects for anadromous fish in the Clearwater River and Salmon River drainages over the last 3 years. Projects included in the evaluation are funded by or proposed for funding by the Bonneville Power Administration (BPA) under the Northwest Power Planning Act as off-site mitigation for downstream hydropower development on the Snake and Columbia rivers. This evaluation project is also funded under the same authority. A mitigation record is being developed to use increased smolt production (i.e., yield) at full-seeding as the best measure of benefit from a habitat enhancement project. Determination of full benefit from a project depends on completion or maturation of the project and presence of adequate numbers of fish to document actual increases in fish production. The depressed nature of upriver anadromous stocks have precluded measuring full benefits of any habitat enhancement project in Idaho. Partial benefit will be credited to the mitigation record in the interim period of run restoration.

  9. Fucoidans from brown seaweeds

    DEFF Research Database (Denmark)

    Ale, Marcel Tutor; Meyer, Anne S.

    2013-01-01

    Fucoidan or fucoidans cover a family of sulfated fucose-rich polysaccharides, built of a backbone of L-fucose units, and characteristically found in brown seaweeds. Fucoidans have potential therapeutic properties, including anti-inflammatory and anti-coagulant activities, as well as anti...

  10. Survival of Trout Strains as Affected by Limnological Parameters

    OpenAIRE

    Wurtsbaugh, Wayne A.; Modde, Timothy; Luecke, Chris; Courtney, Cheryl

    1990-01-01

    Juvenile rainbow trout Oncorhynchus mykiss. (ca. 80 mm S.L.) stocked into mid-elevation reservoirs in Utah are vulnerable to predation from piscivorous fish and birds. I determined how effectively juvenile trout used cover to avoid these predators by using direct observations (snorkel transects) on habitat selection in two reservoirs. Observations of juvenile trout were conducted within five weeks of stocking in 1988 and 1989. During the day juvenile trout were abundant in complex inshore hab...

  11. Survey of Artificial Production of Anadromous Salmonids in the Columbia River Basin, 1981-1985 Final Report.

    Energy Technology Data Exchange (ETDEWEB)

    Washington, Percy M.

    1985-11-25

    The overall objective of this project is to collect, organize, and summarize data concerning anadromous fish culture stations of the Columbia River system for 1981, 1982, and 1983 and to create a data archive system with a means of making this information available to the public.

  12. Molecular crosstalk between a chemical and a biological stressor and consequences on disease manifestation in rainbow trout

    Energy Technology Data Exchange (ETDEWEB)

    Burki, Richard [Centre for Fish and Wildlife Health, University of Bern, Laenggassstrasse 122, CH-3001 Bern (Switzerland); Krasnov, Aleksei [NOFIMA Marin, Postboks. 5010, 1432As (Norway); Bettge, Kathrin [Centre for Fish and Wildlife Health, University of Bern, Laenggassstrasse 122, CH-3001 Bern (Switzerland); Rexroad, Caird E. [National Center for Cool and Cold Water Aquaculture, USDA-ARS, 11876 Leetown Road, Kearneysville, WV 25430 (United States); Afanasyev, Sergey [Sechenov Institute of Evolutionary Physiology and Biochemistry, M. Toreza av. 44, Peterburg 194223 (Russian Federation); Antikainen, Miia [Institute of Applied Biotechnology, University of Kuopio (Finland); Burkhardt-Holm, Patricia [Man-Society-Environment, University of Basel, Vesalgasse 1, CH-4051 Basel (Switzerland); Wahli, Thomas [Centre for Fish and Wildlife Health, University of Bern, Laenggassstrasse 122, CH-3001 Bern (Switzerland); Segner, Helmut, E-mail: helmut.segner@vetsuisse.unibe.ch [Centre for Fish and Wildlife Health, University of Bern, Laenggassstrasse 122, CH-3001 Bern (Switzerland)

    2013-02-15

    The aim of the present study was to examine the molecular and organism reaction of rainbow trout, Oncorhynchus mykiss, to the combined impact of two environmental stressors. The two stressors were the myxozoan parasite, Tetracapsuloides bryosalmonae, which is the etiological agent of proliferative kidney disease (PKD) and a natural stressor to salmonid populations, and 17{beta}-estradiol (E2) as prototype of estrogen-active chemical stressors in the aquatic environment. Both stressors, the parasite and estrogenic contaminants, co-exist in Swiss rivers and are discussed as factors contributing to the decline of Swiss brown trout populations over the last decades. Using a microarray approach contrasting parasite-infected and non-infected rainbow trout at low or high estrogen levels, it was observed that molecular response patterns under joint exposure differed from those to the single stressors. More specifically, three major response patterns were present: (i) expression responses of gene transcripts to one stressor are weakened by the presence of the second stressor; (ii) expression responses of gene transcripts to one stressor are enhanced by the presence of the second stressor; (iii) expression responses of gene transcripts at joint treatment are dominated by one of the two stressors. Organism-level responses to concurrent E2 and parasite treatment - assessed through measuring parasite loads in the fish host and cumulative mortalities of trout - were dominated by the pathogen, with no modulating influence of E2. The findings reveal function- and level-specific responses of rainbow trout to stressor combinations, which are only partly predictable from the response to the single stressors.

  13. Molecular crosstalk between a chemical and a biological stressor and consequences on disease manifestation in rainbow trout

    International Nuclear Information System (INIS)

    The aim of the present study was to examine the molecular and organism reaction of rainbow trout, Oncorhynchus mykiss, to the combined impact of two environmental stressors. The two stressors were the myxozoan parasite, Tetracapsuloides bryosalmonae, which is the etiological agent of proliferative kidney disease (PKD) and a natural stressor to salmonid populations, and 17β-estradiol (E2) as prototype of estrogen-active chemical stressors in the aquatic environment. Both stressors, the parasite and estrogenic contaminants, co-exist in Swiss rivers and are discussed as factors contributing to the decline of Swiss brown trout populations over the last decades. Using a microarray approach contrasting parasite-infected and non-infected rainbow trout at low or high estrogen levels, it was observed that molecular response patterns under joint exposure differed from those to the single stressors. More specifically, three major response patterns were present: (i) expression responses of gene transcripts to one stressor are weakened by the presence of the second stressor; (ii) expression responses of gene transcripts to one stressor are enhanced by the presence of the second stressor; (iii) expression responses of gene transcripts at joint treatment are dominated by one of the two stressors. Organism-level responses to concurrent E2 and parasite treatment – assessed through measuring parasite loads in the fish host and cumulative mortalities of trout – were dominated by the pathogen, with no modulating influence of E2. The findings reveal function- and level-specific responses of rainbow trout to stressor combinations, which are only partly predictable from the response to the single stressors.

  14. Immunity to VHS virus in rainbow trout

    DEFF Research Database (Denmark)

    Lorenzen, Niels; Olesen, Niels Jørgen; Koch, C.

    1999-01-01

    Viral hemorrhagic septicemia virus (VHSV) is the rhabdovirus that causes most disease problems in farmed rainbow trout in Europe. Survivors of infection are usually immune to reinfection but as with other fish viruses, development of a modern recombinant vaccine has been complicated by the limited...... knowledge of the immune mechanisms and antigens involved in induction of immunity. Neutralizing and protective monoclonal antibodies recognize the envelope glycoprotein (G protein) which is the only viral protein known to be present on the surface of the virus particle. Immunoblotting analyses...... with monoclonal antibodies as well as with sera from immunized trout have indicated that protein conformation plays an important role in neutralization epitopes. The virus neutralizing activity often found in sera from convalescent trout is highly dependent on a poorly defined complementing activity in normal...

  15. Laboratory evaluation of a lake trout bioenergetics model

    Science.gov (United States)

    Madenjian, Charles P.; O'Connor, Daniel V.

    1999-01-01

    Lake trout Salvelinus namaycush, aged 3 and 6 years and with average weights of 700 and 2,000 g, were grown in laboratory tanks for up to 407 d under a thermal regime similar to that experienced by lake trout in nearshore Lake Michigan. Lake trout were fed alewifeAlosa pseudoharengus and rainbow smelt Osmerus mordax, prey typical of lake trout in Lake Michigan. Of the 120 lake trout used in the experiment, 40 were fed a low ration (0.25% of their body weight per day), 40 were fed a medium ration (0.5% of their body weight per day), and 40 were fed a high ration (ad libitum). We measured consumption and growth, and we compared observed consumption with that predicted by the Wisconsin bioenergetics model. For lake trout fed the medium ration, model predictions for monthly consumption were unbiased. Moreover, predicted cumulative consumption by medium-ration lake trout for the entire experiment (320 d for smaller lake trout and 407 d for larger lake trout) agreed quite well with observed cumulative consumption; predictions were as close as within 0.1 to 5.2% of observed cumulative consumption. Even so, the model consistently overestimated consumption by low-ration fish and underestimated consumption by high-ration fish. The bias was significant in both cases, but was more severe for the low-ration trout. Because the low-ration and high-ration regimes were probably unrealistic for lake trout residing in Lake Michigan and because the model fit our laboratory data rather well for medium-ration trout, we conclude that applying the Wisconsin bioenergetics model to the Lake Michigan lake trout population in order to estimate the amount of prey fish consumed by lake trout each year is appropriate.

  16. Microsatellite analyses of the trout of northwest Mexico

    Science.gov (United States)

    Nielsen, J.L.; Sage, G.K.

    2001-01-01

    The trout of northwest Mexico represent an undescribed group of fish considered part of the Oncorhynchus mykiss (Pacific trout) complex of species and subspecies. Recent genetic studies have shown these fish to have important genetic diversity and a unique evolutionary history when compared to coastal rainbow trout. Increased levels of allelic diversity have been found in this species at the southern extent of its range. In this study we describe the trout in the Sierra Madre Occidental from the rios Yaqui, Mayo, Casas Grandes and de Bavispe, and their relationship to the more southern distribution of Mexican golden trout (O. chrysogaster) using 11 microsatellite loci. Microsatellite allelic diversity in Mexican trout was high with a mean of 6.6 alleles/locus, average heterozygosity = 0.35, and a mean Fst = 0.43 for all loci combined. Microsatellite data were congruent with previously published mtDNA results showing unique panmictic population structure in the Rio Yaqui trout that differs from Pacific coastal trout and Mexican golden trout. These data also add support for the theory of headwaters transfer of trout across the Continental Divide from tributaries of the Rio de Bavispe into the Rio Casas Grandes. Rio Mayo trout share a close genetic relationship to trout in Rio Yaqui, but sample sizes from the Rio Mayo prevent significant comparisons in this study. Microsatellite analyses show significant allelic frequency differences between Rio Yaqui trout and O. chrysogaster in Sinaloa and Durango Mexico, adding further support for a unique evolutionary status for this group of northwestern Mexican trout.

  17. Fasting augments PCB impact on liver metabolism in anadromous arctic char

    Science.gov (United States)

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

    2006-01-01

    Anadromous arctic char (Salvelinus alpinus) undertake short feeding migrations to seawater every summer and accumulate lipids, while the rest of the year is spent in fresh water where the accumulated lipid reserves are mobilized. We tested the hypothesis that winter fasting and the associated polychlorinated biphenyls' (PCBs) redistribution from lipid depots to critical tissues impair the liver metabolic capacity in these animals. Char were administered Aroclor 1254 (0, 1, 10, and 100 mg/ kg body mass) orally and maintained for 4 months without feeding to mimic seasonal winter fasting, while fed groups (0 and 100 mg Aroclor 1254/kg) were maintained for comparison. A clear dose-related increase in PCB accumulation and cytochrome P4501A (CYP1A) protein content was observed in the livers of fasted fish. This PCB concentration and CYP1A response with the high dose of Aroclor were 1.5-fold and 3-fold greater in the fasted than in the fed fish, respectively. In fed fish, PCB exposure lowered liver glycogen content, whereas none of the other metabolic indicators were significantly affected. In fasted fish, PCB exposure depressed liver glycogen content and activities of glucose-6-phosphate dehydrogenase, alanine aminotransferase, lactate dehydrogenase, and phosphoenolpyruvate carboxykinase and elevated 3-hydroxyacylcoA dehydrogenase activity and glucocorticoid receptor protein expression. There were no significant impacts of PCB on heat shock protein 70 (hsp70) and hsp90 contents in either fed or fasted fish. Collectively, our study demonstrates that winter emaciation associated with the anadromous lifestyle predisposes arctic char to PCB impact on hepatic metabolism including disruption of the adaptive metabolic responses to extended fasting. ?? 2006 Oxford University Press.

  18. Malheur River Basin cooperative bull trout/redband trout research project, annual report FY 1999; ANNUAL

    International Nuclear Information System (INIS)

    The purpose of this study is to document the seasonal distribution of adult/sub-adult bull trout (Salvelinus confluentus) in the Malheur River basin. Due to the decline of bull trout in the Columbia Basin, the United States Fish and Wildlife Service listed bull trout as a threatened species in June 1998. Past land management activities; construction of dams; and fish eradication projects in the North Fork and Middle Fork Malheur River by poisoning have worked in concert to cumulatively impact native species in the Malheur Basin (Bowers et. al. 1993). Survival of the remaining bull trout populations is severely threatened (Buchanan 1997). 1999 Research Objects are: (1) Document the migratory patterns of adult/sub-adult bull trout in the North Fork Malheur River; (2) Determine the seasonal bull trout use of Beulah Reservoir and bull trout entrainment; and (3) Timing and location of bull trout spawning in the North Fork Malheur River basin. The study area includes the Malheur basin from the mouth of the Malheur River located near Ontario, Oregon to the headwaters of the North Fork Malheur River (Map 1). All fish collected and most of the telemetry effort was done on the North Fork Malheur River subbasin (Map 2). Fish collection was conducted on the North Fork Malheur River at the tailwaters of Beulah Reservoir (RK 29), Beulah Reservoir (RK 29-RK 33), and in the North Fork Malheur River at Crane Crossing (RK 69) to the headwaters of the North Fork Malheur. Radio telemetry was done from the mouth of the Malheur River in Ontario, Oregon to the headwaters of the North Fork Malheur. This report will reflect all migration data collected from 3/1/99 to 12/31/99

  19. Searching for Brown Dwarf Outflows

    CERN Document Server

    Whelan, E T; Bacciotti, F; Randich, S; Natta, A

    2009-01-01

    As outflow activity in low mass protostars is strongly connected to ac- cretion it is reasonable to expect accreting brown dwarfs to also be driving out- flows. In the last three years we have searched for brown dwarf outflows using high quality optical spectra obtained with UVES on the VLT and the technique of spectro-astrometry. To date five brown dwarf outflows have been discovered. Here the method is discussed and the results to date outlined.

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

    Science.gov (United States)

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

    2014-01-01

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

  1. Lake Roosevelt Fisheries Evaluation Program; Evaluation of Limiting Factors for Stocked Kokanee and Rainbow Trout in Lake Roosevelt, Washington, 1999 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Baldwin, Casey; Polacek, Matt

    2009-03-01

    Hatchery supplementation of kokanee Oncorhynchus nerka and rainbow trout O. mykiss has been the primary mitigation provided by Bonneville Power Administration for loss of anadromous fish to the waters above Grand Coulee Dam (GCD). The hatchery program for rainbow trout has consistently met management goals and provided a substantial contribution to the fishery; however, spawner returns and creel survey results for kokanee have been below management goals. Our objective was to identify factors that limit limnetic fish production in Lake Roosevelt by evaluating abiotic conditions, food limitations, piscivory, and entrainment. Dissolved oxygen concentration was adequate throughout most of the year; however, levels dropped to near 6 mg/L in late July. For kokanee, warm water temperatures during mid-late summer limited their nocturnal distribution to 80-100 m in the lower section of the reservoir. Kokanee spawner length was consistently several centimeters longer than in other Pacific Northwest systems, and the relative weights of rainbow trout and large kokanee were comparable to national averages. Large bodied daphnia (> 1.7 mm) were present in the zooplankton community during all seasons indicating that top down effects were not limiting secondary productivity. Walleye Stizostedion vitreum were the primary piscivore of salmonids in 1998 and 1999. Burbot Lota lota smallmouth bass Micropterus dolomieui, and northern pikeminnow Ptychocheilus oregonensis preyed on salmonids to a lesser degree. Age 3 and 4 walleye were responsible for the majority (65%) of the total walleye consumption of salmonids. Bioenergetics modeling indicated that reservoir wide consumption by walleye could account for a 31-39% loss of stocked kokanee but only 6-12% of rainbow trout. Size at release was the primary reason for differential mortality rates due to predation. Entrainment ranged from 2% to 16% of the monthly abundance estimates of limnetic fish, and could account for 30% of total

  2. Infectious pancreatic necrosis the trout farmers' dilemma

    Science.gov (United States)

    Parisot, T.J.

    1965-01-01

    Induction of the innate immune pathways is critical for early anti-viral defense but there is limited understanding of how teleost fish recognize viral molecules and activate these pathways. In mammals, Toll-like receptors (TLR) 7 and 8 bind single-stranded RNA of viral origin and are activated by synthetic anti-viral imidazoquinoline compounds. Herein, we identify and describe the rainbow trout (Oncorhynchus mykiss) TLR7 and TLR8 gene orthologs and their mRNA expression. Two TLR7/8 loci were identified from a rainbow trout bacterial artificial chromosome (BAC) library using DNA fingerprinting and genetic linkage analyses. Direct sequencing of two representative BACs revealed intact omTLR7and omTLR8a1 open reading frames (ORFs) located on chromosome 3 and a second locus on chromosome 22 that contains an omTLR8a2 ORF and a putative TLR7pseudogene. We used the omTLR8a1/2 nomenclature for the two trout TLR8 genes as phylogenetic analysis revealed that they and all the other teleost TLR8 genes sequenced to date are similar to the zebrafish TLR8a, but are distinct from the zebrafish TLR8b. The duplicated trout loci exhibit conserved synteny with other fish genomes extending beyond the tandem of TLR7/8 genes. The trout TLR7 and 8a1/2 genes are composed of a single large exon similar to all other described TLR7/8 genes. The omTLR7 ORF is predicted to encode a 1049 amino acid (aa) protein with 84% similarity to the Fugu TLR7and a conserved pattern of predicted leucine-rich repeats (LRR). The omTLR8a1 andomTLR8a2 are predicted to encode 1035- and 1034-aa proteins, respectively, and have 86% similarity to each other. omTLR8a1 is likely the ortholog of the only Atlantic salmonTLR8 gene described to date as they have 95% aa sequence similarity. The tissue expression profiles of omTLR7, omTLR8a1 and omTLR8a2 in healthy trout were highest in spleen tissue followed by anterior and then posterior kidney tissues. Rainbow trout anterior kidney leukocytes produced elevated levels of

  3. Mitochondrial DNA differentiation between two forms of trout Salmo letnica, endemic to the Balkan Lake Ohrid, reflects their reproductive isolation.

    Science.gov (United States)

    Sell, J; Spirkovski, Z

    2004-12-01

    Mitochondrial haplotype diversity in sympatric populations of Ohrid trout, Salmo letnica was investigated by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of the mtDNA control region and ND1, ND3/4, ND5/6 segments. A 310 bp fragment at the 5' end, and a 340-572 bp fragment at the 3' end of the control region were sequenced from representatives of the populations studied. Based on pairwise comparison of the sequences, five new haplotypes were identified plus one identical with the brown trout Andalusian haplotype from the southern Iberian Peninsula. The combination of both RFLP and sequence data sets yielded a total of 10 composite haplotypes. A high degree of genetic subdivision between S. letnica typicus and S. letnica aestivalis populations was observed. The notion of a sympatric origin for the two morphs is discussed. Length variation of the mtDNA control region due to the presence of an 82 bp unit, tandemly repeated one to four times, in the region between the conserved sequence block-3 (CSB-3) and the gene for phenylalanine tRNA is reported. Further, we demonstrate that a single duplication of the approximately 82 bp repeat unit is a common element of the salmonid mitochondrial control region. The unique genetic structure of Ohrid trout represents a highly valuable genetic resource that deserves appropriate management and conservation. PMID:15548279

  4. Preparation and anatomical distribution study of 67Ga-alginic acid nanoparticles for SPECT purposes in rainbow trout (Oncorhynchus mykiss

    Directory of Open Access Journals (Sweden)

    Heidarieh Marzieh

    2014-12-01

    Full Text Available Ergosan contains 1% alginic acid extracted from two brown sea weeds. Little is known about the target organs and anatomical distribution of Ergosan (alginic acid in fish. Therefore, feasibility of developing alginic acid nanoparticles to detect target organ in rainbow trout is interesting. To make nanoparticles, Ergosan extract (alginic acid was irradiated at 30 kGy in a cobalt-60 irradiator and characterized by transmission electron microscopy (TEM and Fourier transform infrared spectroscopy (FTIR. Results from TEM images showed that particle sizes of irradiated alginic acid ranged from 30 to 70 nm. The FTIR results indicated that gamma irradiation had no significant influence on the basic structure of alginic acid. Later, alginic acid nanoparticles were successively labelled with 67Ga-gallium chloride. The biodistribution of irradiated Ergosan in normal rainbow trout showed highest uptake in intestine and kidney and then in liver and kidney at 4- and 24-h post injection, respectively. Single-photon emission computed tomography (SPECT images also demonstrated target specific binding of the tracer at 4- and 24-h post injection. In conclusion, the feed supplemented with alginic acid nanoparticles enhanced SPECT images of gastrointestinal morphology and immunity system in normal rainbow trout.

  5. Tune Your Brown Clustering, Please

    DEFF Research Database (Denmark)

    Derczynski, Leon; Chester, Sean; Bøgh, Kenneth Sejdenfaden

    2015-01-01

    unexplored. Accordingly, we present information for practitioners on the behaviour of Brown clustering in order to assist hyper-parametre tuning, in the form of a theoretical model of Brown clustering utility. This model is then evaluated empirically in two sequence labelling tasks over two text types. We...

  6. Annual Review of BPA-Funded Anadromous Fish Projects, March 18-20, 1986, Holiday Inn Airport, Portland, Oregon.

    Energy Technology Data Exchange (ETDEWEB)

    United States. Bonneville Power Administration.

    1986-02-01

    This report contains descriptions of projects specifically related to anadromous salmonids. They include projects in the following categories: (1) fish and wildlife projects in western Montana; (2) fish health and physiology; (3) habitat enhancement and passage improvement - Oregon I; (4) passage improvement and natural propagation - Washington; (5) habitat enhancement and passage improvements - Oregon II; (6) future hydroelectric assessments; (7) habitat enhancement and passage improvement - Idaho; (8) downstream migration: flows and monitoring; (9) downstream migration: reservoir impacts; and (10) habitat evaluation and monitoring. (ACR)

  7. Marine trophic diversity in an anadromous fish is linked to its life-history variation in fresh water

    OpenAIRE

    Johnson, Susan P.; Schindler, Daniel E.

    2013-01-01

    We used carbon and nitrogen stable isotopes from muscle tissues accrued in the ocean to examine whether marine foraging tactics in anadromous sockeye salmon (Oncorhynchus nerka) are linked to their ultimate freshwater life history as adults. Adults from large-bodied populations spawning in deep freshwater habitats had more enriched δ15N than individuals from small-bodied populations from shallow streams. Within populations, earlier maturing individuals had higher δ15N than older fish. These d...

  8. Molecular Characteristic, Protein Distribution and Potential Regulation of HSP90AA1 in the Anadromous Fish Coilia nasus

    OpenAIRE

    Di-An Fang; Jin-Rong Duan; Yan-Feng Zhou; Min-Ying Zhang; Dong-Po Xu; Kai Liu; Pao Xu

    2016-01-01

    Heat shock proteins play essential roles in basic cellular events. Spawning migration is a complex process, with significant structural and biochemical changes taking place in the adult gonad. To date, the molecular mechanisms underlying migration reproductive biology remain undetermined. In this regard, a full length HSP90AA1 comprising 2608 nucleotides from the anadromous fish Coilia nasus was characterized, encoding 742 amino acid (aa) residues with potential phosphorylation sites. HSP90AA...

  9. Restricted gene flow at the micro- and macro-geographical scale in marble trout based on mtDNA and microsatellite polymorphism

    Directory of Open Access Journals (Sweden)

    Patarnello Tomaso

    2011-04-01

    Full Text Available Abstract Background The genetic structure of the marble trout Salmo trutta marmoratus, an endemic salmonid of northern Italy and the Balkan peninsula, was explored at the macro- and micro-scale level using a combination of mitochondrial DNA (mtDNA and microsatellite data. Results Sequence variation in the mitochondrial control region showed the presence of nonindigenous haplotypes indicative of introgression from brown trout into marble trout. This was confirmed using microsatellite markers, which showed a higher introgression at nuclear level. Microsatellite loci revealed a strong genetic differentiation across the geographical range of marble trout, which suggests restricted gene flow both at the micro-geographic (within rivers and macro-geographic (among river systems scale. A pattern of Isolation-by-Distance was found, in which genetic samples were correlated with hydrographic distances. A general West-to-East partition of the microsatellite polymorphism was observed, which was supported by the geographic distribution of mitochondrial haplotypes. Conclusion While introgression at both mitochondrial and nuclear level is unlikely to result from natural migration and might be the consequence of current restocking practices, the pattern of genetic substructuring found at microsatellites has been likely shaped by historical colonization patterns determined by the geological evolution of the hydrographic networks.

  10. Umatilla River Basin Anadromous Fsh Habitat Enhancement Project : 2000 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, R. Todd

    2001-12-31

    The Umatilla River Basin Anadromous Fish Habitat Enhancement Project continued to identify impacted stream reaches throughout the Umatilla River Basin for habitat improvements during the 2000 project period. Public outreach efforts, biological and physical monitoring, and continued development of a Umatilla River Basin Watershed Assessment assisted the project in fostering public cooperation, targeting habitat deficiencies and determining habitat recovery measures. Habitat enhancement projects continued to be maintained on 44 private properties, four riparian easements and one in-stream enhancement agreement were secured, two new projects implemented and two existing projects improved to enhance anadromous fish habitat and natural fisheries production capabilities in the Umatilla River Basin. New project locations included sites on the mid Umatilla River and Buckaroo Creek. Improvements were implemented at existing project sites on the upper Umatilla River and Wildhorse Creek. A stream bank stabilization project was implemented at approximately River Mile 37.4 Umatilla River to stabilize 760 feet of eroding stream bank and improve in-stream habitat diversity. Habitat enhancements at this site included construction of six rock barbs with one large conifer root wad incorporated into each barb, stinging approximately 10,000 native willow cuttings, planting 195 tubling willows and 1,800 basin wildrye grass plugs, and seeding 40 pounds of native grass seed. Staff time to assist in development of a subcontract and fence materials were provided to establish eight spring sites for off-stream watering and to protect wetlands within the Buckaroo Creek Watershed. A gravel bar was moved and incorporated into an adjacent point bar to reduce stream energy and stream channel confinement within the existing project area at River Mile 85 Umatilla River. Approximately 10,000 native willow cuttings were stung and trenched into the stream channel margins and stream banks, and 360

  11. CTUIR Umatilla Anadromous Fisheries Habitat Project : A Columbia River Basin Fish Habitat Project 2008 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Hoverson, Eric D.; Amonette, Alexandra

    2009-02-09

    The Umatilla Anadromous Fisheries Habitat Project (UAFHP) is an ongoing effort to protect, enhance, and restore riparian and instream habitat for the natural production of anadromous salmonids in the Umatilla River Basin, Northeast Oregon. Flow quantity, water temperature, passage, and lack of in-stream channel complexity have been identified as the key limiting factors in the basin. During the 2008 Fiscal Year (FY) reporting period (February 1, 2008-January 31, 2009) primary project activities focused on improving instream and riparian habitat complexity, migrational passage, and restoring natural channel morphology and floodplain function. Eight primary fisheries habitat enhancement projects were implemented on Meacham Creek, Birch Creek, West Birch Creek, McKay Creek, West Fork Spring Hollow, and the Umatilla River. Specific restoration actions included: (1) rectifying one fish passage barrier on West Birch Creek; (2) participating in six projects planting 10,000 trees and seeding 3225 pounds of native grasses; (3) donating 1000 ft of fencing and 1208 fence posts and associated hardware for 3.6 miles of livestock exclusion fencing projects in riparian areas of West Birch and Meacham Creek, and for tree screens to protect against beaver damage on West Fork Spring Hollow Creek; (4) using biological control (insects) to reduce noxious weeds on three treatment areas covering five acres on Meacham Creek; (5) planning activities for a levee setback project on Meacham Creek. We participated in additional secondary projects as opportunities arose. Baseline and ongoing monitoring and evaluation activities were also completed on major project areas such as conducting photo point monitoring strategies activities at the Meacham Creek Large Wood Implementation Project site (FY2006) and at additional easements and planned project sites. Fish surveys and aquatic habitat inventories were conducted at project sites prior to implementation. Proper selection and implementation of

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

    Science.gov (United States)

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

    2004-01-01

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

  13. DENMARK – EUROPEAN CHAMPION IN ORGANIC RAINBOW TROUT

    OpenAIRE

    Larsen, Erling P.; Nielsen, Max; Larsen, Villy J.; Jokumsen, Alfred

    2016-01-01

    In 2014 Denmark was the biggest producer of organic rainbow trout in Europe with a total amount of 1,080 tons. The producers of the organic trout had a better economic earning than the conventional producers, measured per unit produced. The value wason average 8 % higher per unit than for the conventional producers. The solvency ratio was in 2012 an average of 28 %, which was higher than the traditional trout producers’ solvency ratio (solvency ratio measure an enterprises ability to meet its...

  14. Sensitivity of Trout to Chronic Acute Exposure to Selenium

    DEFF Research Database (Denmark)

    Nielsen, Gunnar Gissel; Nielsen, M. Gissel

    1978-01-01

    Trout were exposed to selenite (Na2SeO3) solutions of varying concentrations (0.1-100 ppm Se) for periods of up to 4 wk. A chronic exposure to 0.1 ppm Se or less is non-lethal to trout. Lethality at higher concentrations depends on the length of exposure. Trout that survive for 10 days in tap-water...

  15. TROUT STEAKS: CONSUMER PERCEPTIONS OF A NEW FOOD ITEM

    OpenAIRE

    Dasgupta, Siddhartha; Foltz, John C.; Jacobsen, Bonnie

    2000-01-01

    Water quality standards and a limited water supply have dramatically restricted the expansion of the U.S. trout industry. Faced with production restrictions, producers have turned to value-added products to strengthen the economic growth of the industry. In the near future, trout steaks could surface in retail outlets as a new revenue source for the mature trout industry. A telephone survey of consumers in Chicago and Los Angeles was conducted by the University of Idaho in the spring of 1997 ...

  16. CONSUMER PERCEPTIONS OF TROUT AS A FOOD ITEM

    OpenAIRE

    Foltz, John C.; Dasgupta, Siddhartha; Devadoss, Stephen

    1999-01-01

    The impacts of socioeconomic/demographic characteristics, experiences and preferences of consumers on trout purchasing decisions were estimated using Probit and Ordered Probit regression techniques. Data from a survey of consumer purchasing behavior and personal attributes were used to deduce factors that led to either a high or low likelihood of purchasing trout products. Analysis of data pertaining to whole trout and value-added products yielded consistently different characteristics of con...

  17. Stock Summary Reports for Columbia River Anadromous Salmonids, Volume V; Idaho Subbasins, 1992 CIS Summary Report.

    Energy Technology Data Exchange (ETDEWEB)

    Keifer, Sharon (Idaho Department of Fish and Game, Boise, ID); Rowe, Mike (Shoshone-Bannock Tribes, Fort Hall, ID); Hatch, Keith (Columbia River Inter-Tribal Fish Commission, Portland, OR)

    1993-05-01

    An essential component of the effort to rebuild the Columbia Basin's anadromous fish resources is that available information and experience be organized and shared among numerous organizations and individuals. Past experience and knowledge must form the basis for actions into the future. Much of this knowledge exists only in unpublished form in agency and individual files. Even that information which is published in the form of technical and contract reports receives only limited distribution and is often out of print and unavailable after a few years. Only a small fraction of the basin's collective knowledge is captured in permanent and readily available databases (such as the Northwest Environmental Database) or in recognized journals. State, tribal, and federal fishery managers have recognized these information management problems and have committed to a program, the Coordinated Information System Project, to capture and share more easily the core data and other information upon which management decisions are based. That project has completed scoping and identification of key information needs and development of a project plan. Work performed under the CIS project will be coordinated with and extend information contained in the Northwest Environmental Database. Construction of prototype systems will begin in Phase 3. This report is one in a series of seven describing the results of the Coordinated Information System scoping and needs identification phase. A brief description of each of these reports is given.

  18. Monitoring anadromous fish populations in a context of habitat fragmentation and commercial exploitation

    Directory of Open Access Journals (Sweden)

    Gabriela Ribeiro Cardoso

    2015-12-01

    A video recording system was used to monitor fishway effectiveness. Simultaneously, eight abiotic parameters were continuously recorded. Boosted Regression Trees (BRTs were applied to relate fishway’s use by sea lamprey and Alosa spp. with abiotic predictors. A passive integrated transponder (PIT antenna system was also used to quantify passage efficiency for sea lampreys. A sample of the professional fisherman population was surveyed, and respective daily catches registered. Data counts, fishway efficiency and professional fishermen surveys allowed the estimation of the number of sea lampreys entering River Mondego to spawn. Video counts revealed that 8333 and 21979 sea lampreys, in 2013 and 2014, respectively, used the fishway, and 7503 and 3404 Alosa spp. passed during the same periods. BRTs identified flow as the most important variable explaining fishway use, suggesting that anadromous species prefer to use the fishway at relatively low flow conditions. About 30% of PIT-tagged lampreys transposed the fishway in the migratory season of 2014. Data surveys indicate a total catch of 11114 and 31746 sea lampreys, during 2013 and 2014, respectively, and 3053 and 6637 allis shads in the same seasons. Hence, we estimated that 38891 and 105006 sea lampreys entered River Mondego to reproduce in 2013 and 2014, respectively.

  19. Comparison of biochemical parameters of rainbow trout (Oncorhynchus mykiss) reared in two different trout farms'

    Science.gov (United States)

    Karatas, Tayfun

    2016-04-01

    The aim of this study was to compare biochemical parameters of cultured rainbow trouts (Oncorhynchus mykiss, Walbaum, 1972) reared in two different trout farms' (Agri and Erzurum). The average weights of fish were 150±10gr for first station (Agri), 230±10gr for second station (Erzurum). Fishes used in research were randomly caught from pools, and fifteen pieces were used for each group. Fishes were fed with commercial trout feed with 45-50% crude protein twice a day. The levels of AST, ALT, LDL, total cholesterol and triglyceride in the second station (Erzurum) were found to be higher (pLDL, triglyceride may be associated with size, sex, sexual maturity and environmental conditions (temperature, pH, hardness and dissolved oxygen).

  20. Brook trout passage performance through culverts

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2009-01-01

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

  2. SuchThatCast Episode 3: J.D. Trout

    NARCIS (Netherlands)

    Søraker, J.H.

    2012-01-01

    SuchThatCast goes mobile in the third episode, as I interview J.D. Trout on the appr. 2 hour train ride between Enschede and Schiphol airport. Trout received his PhD in Philosophy at Cornell University and is currently Professor of Philosophy and Psychology at Loyola University Chicago. He was recen

  3. The Effects of Acute Stress on Rainbow Trout (Oncorhynchus mykiss)

    OpenAIRE

    KUBİLAY, Ayşegül

    2002-01-01

    The physiological effects of acute stressors (transport, handling, netting and confinement) on rainbow trout in an aquaculture system were investigated. Serum cortisol level, serum glucose and lysozyme activity were determined in rainbow trout stressed by acute stressors, and compared with those of unstressed (control) fish. Serum cortisol, glucose levels and lysozyme activity were significantly higher(P

  4. Challenge models for RTFS in rainbow trout fry (Oncorhynchus mykiss)

    DEFF Research Database (Denmark)

    Henriksen, Maya Maria Mihályi; Madsen, Lone; Dalsgaard, Inger

    2011-01-01

    The fish pathogen Flavobacterium psychrophilum is one of the main causes of mortality in fry of farmed rainbow trout (Oncorhynchus mykiss) and other salmonid fish. The disease following infection is often called bacterial coldwater disease (BCWD) in USA and rainbow trout fry syndrome (RTFS) in...

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

    DEFF Research Database (Denmark)

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

    2010-01-01

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

  6. P-gp expression in brown trout erythrocytes: evidence of a detoxification mechanism in fish erythrocytes

    OpenAIRE

    Emeline Valton; Christian Amblard; Ivan Wawrzyniak; Frederique Penault-Llorca; Mahchid Bamdad

    2013-01-01

    Blood is a site of physiological transport for a great variety of molecules, including xenobiotics. Blood cells in aquatic vertebrates, such as fish, are directly exposed to aquatic pollution. P-gp are ubiquitous “membrane detoxification proteins” implicated in the cellular efflux of various xenobiotics, such as polycyclic aromatic hydrocarbons (PAHs), which may be pollutants. The existence of this P-gp detoxification system inducible by benzo [a] pyrene (BaP), a highly cytotoxic PAH, was inv...

  7. Density-dependent interactions in an Arctic char - brown trout system: competition, predation, or both?

    NARCIS (Netherlands)

    L. Persson; P.A. Amundsen; A.M. de Roos; R. Knudsen; R. Primicerio; A. Klemetsen

    2013-01-01

    In the study of mechanisms structuring fish communities, mixed competition-predation interactions where large predators feed on prey fish versus those in which small predators compete with prey fish for a shared prey have been the focus of substantial research. We used a long-term data set from a sy

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

    DEFF Research Database (Denmark)

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

    2014-01-01

    was determined for the four variables; water velocity, water depth, substrate and cover, and the preferences for physical habitat selection were expressed in terms of habitat suitability indices (HSI's). The statistical confidence of HSI's was evaluated using power analysis. It was found that a minimum of 22...... fish observations was needed to have statistical confidence in the HSIs for water depth, and a minimum of 92 fish observations for water velocity during daytime summer conditions. Generally parr were utilising the deeper habitats, indicating preference for deeper water. Cover was also being selected...... for at all sites, but selection was inconsistent among sites for the variables substrate and velocity. The results indicate that during daytime summer conditions water depth is a significant variable for parr habitat selection in these small lowland streams, with cover also being important. Therefore...

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

    OpenAIRE

    2016-01-01

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

  10. Relationship between oxidative stress and circulating testosterone and cortisol in pre-spawning female brown trout

    NARCIS (Netherlands)

    Hoogenboom, Mia O.; Metcalfe, Neil B.; Groothuis, Ton G. G.; de Vries, Bonnie; Costantini, David

    2012-01-01

    Reproduction in vertebrates is an energy-demanding process that is mediated by endogenous hormones and potentially results in oxidative stress. The primary aim of this study was to quantify the relationship between oxidative stress parameters (antioxidant capacity and levels of reactive oxygen metab

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

    DEFF Research Database (Denmark)

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

    2000-01-01

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

  12. Stress Coping Strategies in Brown Trout (Salmo Trutta): Ecological Significance and Effects of Sea-Ranching

    OpenAIRE

    Brelin, Daniel

    2008-01-01

    Two distinct stress coping strategies, proactive and reactive, have been stated in various animal studies, each associated with a set of behavioural and physiological characteristics. In a given challenging situation, proactive animals show more aggression, a higher general activity and a predominant sympathetic reaction. In contrast, the reactive copers respond more with immobility and avoidance, and a predominant parasympathetic/hypothalamic activation. This divergence in coping has also be...

  13. Effects of density on foraging success and aggression in age-structured groups of brown trout

    DEFF Research Database (Denmark)

    Kaspersson, Rasmus; Höjesjö, Johan; Pedersen, Stig

    2010-01-01

    decrease with increasing under-yearling density and that the frequency of defence (i.e. aggression) would peak at an intermediate density. As predicted, yearlings made significantly more unsuccessful foraging attempts and adopted darker body coloration at high density of under-yearlings, suggesting...... increased stress levels. However, in contrast to our second prediction, the number of aggressive interactions increased progressively with density. These novel findings suggest that the cost of defence increases with under-yearling density, probably as a consequence of stress from interference with under...

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

    DEFF Research Database (Denmark)

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

    2008-01-01

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

  15. Status of Oregon's Bull Trout.

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-10-01

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

  16. Umatilla River Basin Anadromous Fish Habitat Enhancement Project : 2001 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, R. Todd; Sexton, Amy D.

    2003-02-01

    The Umatilla River Basin Anadromous Fish Habitat Enhancement Project continued to identify impacted stream reaches throughout the Umatilla River Basin for habitat improvements during the 2001 project period. Public outreach efforts, biological and physical monitoring, and continued development of a Umatilla Subbasin Watershed Assessment assisted the project in fostering public cooperation, targeting habitat deficiencies and determining habitat recovery measures. Projects continued to be maintained on 49 private properties, one 25-year Non-Exclusive Bureau of Indian Affairs' Easement was secured, six new projects implemented and two existing project areas improved to enhance anadromous fish habitat. New project locations included sites on the mid Umatilla River, upper Umatilla River, Mission Creek, Cottonwood Creek and Buckaroo Creek. New enhancements included: (1) construction of 11,264 feet of fencing between River Mile 43.0 and 46.5 on the Umatilla River, (2) a stream bank stabilization project implemented at approximately River Mile 63.5 Umatilla River to stabilize 330 feet of eroding stream bank and improve instream habitat diversity, included construction of eight root wad revetments and three boulder J-vanes, (3) drilling a 358-foot well for off-stream livestock watering at approximately River Mile 46.0 Umatilla River, (4) installing a 50-foot bottomless arch replacement culvert at approximately River Mile 3.0 Mission Creek, (5) installing a Geoweb stream ford crossing on Mission Creek (6) installing a 22-foot bottomless arch culvert at approximately River Mile 0.5 Cottonwood Creek, and (7) providing fence materials for construction of 21,300 feet of livestock exclusion fencing in the Buckaroo Creek Drainage. An approximate total of 3,800 native willow cuttings and 350 pounds of native grass seed was planted at new upper Umatilla River, Mission Creek and Cottonwood Creek project sites. Habitat improvements implemented at existing project sites included

  17. Intestinal fluid absorption in anadromous salmonids: importance of tight junctions and aquaporins

    Directory of Open Access Journals (Sweden)

    Kristina eSundell

    2012-09-01

    Full Text Available The anadromous salmonid life cycle includes both fresh water (FW and seawater (SW stages. The parr-smolt transformation (smoltification pre–adapt the fish to SW while still in FW. The osmoregulatory organs change their mode of action from a role of preventing water inflow in FW, to absorb ions to replace water lost by osmosis in SW. During smoltification, the drinking rate increases, in the intestine the ion and fluid transport increases and is further elevated after SW entry. In SW, the intestine absorbs ions to create an inwardly directed water flow which is accomplished by increased Na+,K+-ATPase (NKA activity in the basolateral membrane, driving ion absorption via ion channels and/or co-transporters. This review will aim at discussing the expression patterns of the ion transporting proteins involved in intestinal fluid absorption in the FW stage, during smoltification and after SW entry. Of equal importance for intestinal fluid absorption as the active absorption of ions, is the permeability of the epithelium to ions and water. During the smoltification the increase in NKA activity and water uptake in SW is accompanied by decreased paracellular permeability suggesting a redirection of the fluid movement from a paracellular route in FW, to a transcellular route in SW. Increased transcellular fluid absorption could be achieved by incorporation of aquaporins (AQPs into the enterocyte membranes and/or by a change in fatty acid profile of the enterocyte lipid bilayer. An increased incorporation of unsaturated fatty acids into the membrane phospholipids will increase water permeability by enhancing the fluidity of the membrane. A second aim of the present review is therefore to discuss the presence and regulation of expression of AQPs in the enterocyte membrane as well as to discuss the profile of fatty acids present in the membrane phospholipids during different stages of the salmonid lifecycle.

  18. Umatilla River Basin Anadromous Fish Habitat Enhancement Project : 1995 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, R.Todd

    1996-05-01

    During the 1995 - 96 project period, four new habitat enhancement projects were implemented under the Umatilla River Basin Anadromous Fish Habitat Enhancement Project by the Confederated Tribes of the Umatilla Indian Reservation (CTUIR) in the upper Umatilla River Basin. A total of 38,644 feet of high tensile smooth wire fencing was constructed along 3.6 miles of riparian corridor in the Meacham Creek, Wildhorse Creek, Greasewood Creek, West Fork of Greasewood Creek and Mission Creek watersheds. Additional enhancements on Wildhorse Creek and the lower Greasewood Creek System included: (1) installation of 0.43 miles of smooth wire between river mile (RM) 10.25 and RM 10.5 Wildhorse Creek (fence posts and structures had been previously placed on this property during the 1994 - 95 project period), (2) construction of 46 sediment retention structures in stream channels and maintenance to 18 existing sediment retention structures between RM 9.5 and RM 10.25 Wildhorse Creek, and (3) revegetation of stream corridor areas and adjacent terraces with 500 pounds of native grass seed or close species equivalents and 5,000 native riparian shrub/tree species to assist in floodplain recovery, stream channel stability and filtering of sediments during high flow periods. U.S. Fish and Wildlife Service (USFWS), Bureau of Indian Affairs (BIA) and Environmental Protection Agency (EPA) funds were cost shared with Bonneville Power Administration (BPA) funds, provided under this project, to accomplish habitat enhancements. Water quality monitoring continued and was expanded for temperature and turbidity throughout the upper Umatilla River Watershed. Physical habitat surveys were conducted on the lower 13 river miles of Wildhorse Creek and within the Greasewood Creek Project Area to characterize habitat quality and to quantify various habitat types by area.

  19. Relaxin-related gene expression differs between anadromous and stream-resident stickleback (Gasterosteus aculeatus) following seawater transfer.

    Science.gov (United States)

    Kusakabe, Makoto; Ishikawa, Asano; Kitano, Jun

    2014-09-01

    Relaxin (RLN) is a hormone that was originally identified as a regulator of pregnancy and reproduction. However, recent mammalian studies have demonstrated that relaxins also have potent osmoregulatory actions. In mammals, six relaxin family peptides have been identified: RLN1/2, RLN3, insulin-like peptide (INSL) 3, INSL4, INSL5, and INSL6. Previous genome database searches have revealed that teleosts also possess multiple relaxin family genes. However, the functions of these relaxin family peptides in teleosts remain unclear. In order to gain insight into the osmoregulatory functions of teleost relaxins, we studied the relaxin family peptides in euryhaline three-spined sticklebacks (Gasterosteus aculeatus), which have diversified into a variety of ecotypes. Rln3a, rln3b, and rln transcripts were abundant in the stickleback brain, whereas insl5b transcript levels were highest in the intestine among tissues. Seawater challenge experiments showed that transcript levels of rln3a, rln3b, and rln in the brain changed significantly after seawater transfer. Particularly, rln3b showed different patterns of temporal changes between anadromous and stream-resident morphs. The transcript levels of relaxin family peptide receptors, rxfp1, rxfp2b, rxfp3-2a, and rxfp3-2b, did not exhibit substantial changes in the brain, although these were constantly higher in the anadromous morph than the stream-resident morph. These results suggest that stickleback relaxin systems are differentially regulated by salinity signals, at least at the transcriptional level, and anadromous and stream-resident morphs differ in relaxin signaling pathways. The differences in the expression of relaxin-related genes between these two morphs provide a foundation for further exploration of the osmoregulatory function of relaxins in teleosts. PMID:24973563

  20. A Multiple Watershed Approach to Assessing the Effects of Habitat Restoration Actions on Anadromous and Resident Fish Populations, Technical Report 2003-2004.

    Energy Technology Data Exchange (ETDEWEB)

    Marmorek, David

    2004-03-01

    Habitat protection and restoration is a cornerstone of current strategies to restore ecosystems, recover endangered fish species, and rebuild fish stocks within the Columbia River Basin. Strategies featuring habitat restoration include the 2000 Biological Opinion on operation of the Federal Columbia River Power System (FCRPS BiOp) developed by the National Marine Fisheries Service (NMFS), the 2000 Biological Opinion on Bull Trout developed by the US Fish and Wildlife Service (USFWS), and Sub-Basin Plans developed under the Fish and Wildlife Program of the Northwest Power and Conservation Council (NWPCC). There is however little quantitative information about the effectiveness of different habitat restoration techniques. Such information is crucial for helping scientists and program managers allocate limited funds towards the greatest benefits for fish populations. Therefore, it is critical to systematically test the hypotheses underlying habitat restoration actions for both anadromous and resident fish populations. This pilot project was developed through a proposal to the Innovative Projects fund of the NWPCC (ESSA 2002). It was funded by the Bonneville Power Administration (BPA) following reviews by the Independent Scientific Review Panel (ISRP 2002), the Columbia Basin Fish and Wildlife Authority (CBFWA 2002), the NWPCC and BPA. The study was designed to respond directly to the above described needs for information on the effectiveness of habitat restoration actions, including legal measures specified in the 2000 FCRPS BiOp (RPA 183, pg. 9-133, NMFS 2000). Due to the urgency of addressing these measures, the timeline of the project was accelerated from a duration of 18 months to 14 months. The purpose of this pilot project was to explore methods for evaluating past habitat restoration actions and their effects on fish populations. By doing so, the project will provide a foundation of retrospective analyses, on which to build prospective, multi-watershed designs

  1. Rainbow Trout Haematology Coinciding with Metabolic Requirement

    Directory of Open Access Journals (Sweden)

    Ghulam Nabi LONE

    2012-12-01

    Full Text Available Rainbow trout (Onchorhynchus mykiss are an important aquaculture species yet there are few diagnostic tools available to assess their health. There is little published information regarding age-related changes in blood values of juvenile fish. It is important to evaluate juvenile fish, as this is the time they are raised in aquaculture settings. Determining age-related changes in the blood values of fishes would further develop clinical pathology as a diagnostic tool, enhancing both fish medicine and the aquaculture industry. The results of standard hematology and clinical chemistry analysis were evaluated in juvenile rainbow trout at 4, 6, 9, 15 and 19 months of age. Values for PCV and RBC indices were significantly lower, and plasma protein concentration was significantly higher in younger fish. Total WBC and lymphocyte counts were significantly higher in fish at 6 and 9 months of age, while neutrophil and monocyte counts were higher at 6, 9 and 15 months. Eosinophil counts were significantly higher in 9 month old fish. The majority of hematologic values fell within previously established reference intervals, indicating that only slight modification to the intervals is necessary for evaluating hematologic results of rainbow trout at different ages. The following analytes deviated sufficiently from adult reference intervals to warrant separate reference values: plasma protein concentration at 4 months, WBC and lymphocyte counts at 15 and 19 months, and thrombocyte-like-cells at 9 months of age. Values for most biochemical analytes were significantly different among age groups except for creatinine and potassium concentrations. Comparisons with reference intervals were not made for biochemical analytes, because established reference intervals were not available.

  2. The signatures of stable isotopes δ 15N and δ 13C in anadromous and non-anadromous Coilia nasus living in the Yangtze River, and the adjacent sea waters

    Science.gov (United States)

    Wang, Lei; Tang, Wenqiao; Dong, Wenxia

    2015-12-01

    Stable isotopes are increasingly used to investigate seasonal migrations of aquatic organisms. This study employed stable isotopes ( δ 13C and δ 15N) for Coilia nasus from the lower Yangtze River and the adjacent East China Sea to distinguish different ecotypic groups, ascertain trophic nutrition positions, and reflect environmental influences on C. nasus. δ 13C signatures of C. nasus sampled from Zhoushan (ZS), Chongming (CM), and Jingjiang (JJ) waters were significantly higher than those from the Poyang Lake (PYL) ( P nutrition positions in the marine and Poyang Lake food webs, respectively. C. nasus in Poyang Lake were significantly more enriched in δ 15N but depleted in δ 13C, suggesting that anthropogenic nutrient inputs and terrigenous organic carbon are important to the Poyang Lake food web. This study is the first to apply δ 15N and δ 13C to population assignment studies of C. nasus in the Yangtze River and its affiliated waters. Analysis of stable isotopes ( δ 15N and δ 13C) is shown to be a useful tool for discriminating anadromous and non-anadromous C. nasus.

  3. An obscure disease of rainbow trout

    Science.gov (United States)

    Rucker, R.R.; Yasutake, W.T.; Wedemeyer, G.

    1970-01-01

    An annul mortality among Rainbow Trout (Salmo gairdneri) has plagued the Shelton Hatchery of the Washington State Department of Game for the last several years. No infectious agent could be isolated from the moribund fish, but histopathologica1 changes in the liver of 1-month-old fish suggested the presence of a toxic substance. Scoliosis in 3-month-old fish suggested a possible deficiency in vitamin C. With this background in mind, we designed studies to determine the nature and source of possible toxicants and the role of vitamin C deficiency in the etiology of this disease.

  4. Taxonomy Icon Data: rainbow trout [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available rainbow trout Oncorhynchus mykiss Chordata/Vertebrata/Pisciformes Oncorhynchus_mykiss_L.png Oncorhynchus_my...kiss_NL.png Oncorhynchus_mykiss_S.png Oncorhynchus_mykiss_NS.png http://biosciencedbc.jp/taxonomy..._icon/icon.cgi?i=Oncorhynchus+mykiss&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Oncorhynchus+my...kiss&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Oncorhynchus+my...kiss&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Oncorhynchus+mykiss&t=NS ...

  5. Reevaluation of lake trout and lake whitefish bioenergetics models

    Science.gov (United States)

    Madenjian, Charles P.; Pothoven, Steve A.; Kao, Yu-Chun

    2013-01-01

    Using a corrected algorithm for balancing the energy budget, we reevaluated the Wisconsin bioenergetics model for lake trout (Salvelinus namaycush) in the laboratory and for lake whitefish (Coregonus clupeaformis) in the laboratory and in the field. For lake trout, results showed that the bioenergetics model slightly overestimated food consumption by the lake trout when they were fed low and intermediate rations, whereas the model predicted food consumption by lake trout fed ad libitum without any detectable bias. The slight bias in model predictions for lake trout on restricted rations may have been an artifact of the feeding schedule for these fish, and we would therefore recommend application of the Wisconsin lake trout bioenergetics model to lake trout populations in the field without any revisions to the model. Use of the Wisconsin bioenergetics model for coregonids resulted in overestimation of food consumption by lake whitefish both in the laboratory and in the field by between 20 and 30%, on average. This overestimation of food consumption was most likely due to overestimation of respiration rate. We therefore adjusted the respiration component of the bioenergetics model to obtain a good fit to the observed consumption in our laboratory tanks. The adjusted model predicted the consumption in the laboratory and the field without any detectable bias. Until a detailed lake whitefish respiration study can be conducted, we recommend application of our adjusted version of the Wisconsin generalized coregonid bioenergetics model to lake whitefish populations in the field.

  6. The rotation of brown dwarfs

    CERN Document Server

    Scholz, Aleks

    2016-01-01

    One of the characteristic features of low-mass stars is their propensity to shed large amounts of angular momentum throughout their evolution. This distinguishs them from brown dwarfs which remain fast rotators over timescales of gigayears. Brown dwarfs with rotation periods longer than a couple of days have only been found in star forming regions and young clusters. This is a useful constraint on the mass dependency of mechanisms for angular momentum regular in stars. Rotational braking by disks and winds become highly inefficient in the substellar regime. In this short review I discuss the observational evidence for the fast rotation in brown dwarfs, the implications, and the link to the spin-mass relation in planets.

  7. Seasonal changes in hepatocytic lipid droplets, glycogen deposits, and rough endoplasmic reticulum along the natural breeding cycle of female ohrid trout (Salmo letnica Kar.)-A semiquantitative ultrastructural study.

    Science.gov (United States)

    Jordanova, Maja; Rebok, Katerina; Malhão, Fernanda; Rocha, Maria J; Rocha, Eduardo

    2016-08-01

    This study on wild female Ohrid trout was primarily designed to provide a general overview of the breeding cycle influence upon selected aspects of hepatocytes. According with a semiquantitatively evaluation, some of these cell's structural compartments change during the breeding cycle. Structural modifications were disclosed in the relative occurrence of lipid, glycogen, and RER content during breeding cycle. The relative amount of lipid deposits in the hepatocytes was much greater in previtellogenesis, and decreased postspawning. So, while the seasonal changes in RER were positively related with the ovary maturation status, those of the lipid droplets followed an opposite trend. The hepatocytic glycogen occurred rarely, mainly in late-vitellogenesis and spawning, suggesting that in this species such kind of energy storage is comparatively unimportant. Lipid accumulation and later usage is, probably, the relevant biochemical pathway for Ohrid trout in the wild. While glycogen and RER contents were positively correlated with the gonadosomatic index, lipids were negatively correlated. Additionally, glycogen inclusions were positively correlated with the plasma estradiol levels. When comparing seasonal patterns from wild Ohrid trout with those from well-studied rainbow and brown trout (specimens studied were from aquaculture), there are contradicting results as to lipid and glycogen reserves, and also as to RER loads. The differences among the mentioned trout can result from intrinsic interspecies differences or may be associated with natural feeding conditions versus feeding with commercially prepared diets, or other factors. This study offers new data useful as standard to access liver pathology in wild and aquacultured Ohrid trout. Microsc. Res. Tech. 79:700-706, 2016. © 2016 Wiley Periodicals, Inc. PMID:27223583

  8. Vertebral column deformities in farmed rainbow trout ( Oncorhynchus mykiss )

    DEFF Research Database (Denmark)

    Madsen, Lone; Dalsgaard, Inger

    1999-01-01

    Farmed rainbow trout (Oncorhynchus mykiss) were fed diets with either different levels of vitamin C, or diets enriched with glucan or chitin, from feeding start and 6 months onwards. At an average weight of 100 g, the trout were X-rayed to determine the deformity level. The investigations showed...... deformities (4.8%). In all groups examined, the deformities were spread over the whole vertebral column. The deformities in the group fed the low vitamin C diet were more severe than those found in the other groups. An outbreak of the disease rainbow trout fry syndrome (RTFS) caused by the bacterium...

  9. Acoustic estimates of abundance and distribution of spawning lake trout on Sheboygan Reef in Lake Michigan

    Science.gov (United States)

    Warner, D.M.; Claramunt, R.M.; Janssen, J.; Jude, D.J.; Wattrus, N.

    2009-01-01

    Efforts to restore self-sustaining lake trout (Salvelinus namaycush) populations in the Laurentian Great Lakes have had widespread success in Lake Superior; but in other Great Lakes, populations of lake trout are maintained by stocking. Recruitment bottlenecks may be present at a number of stages of the reproduction process. To study eggs and fry, it is necessary to identify spawning locations, which is difficult in deep water. Acoustic sampling can be used to rapidly locate aggregations of fish (like spawning lake trout), describe their distribution, and estimate their abundance. To assess these capabilities for application to lake trout, we conducted an acoustic survey covering 22 km2 at Sheboygan Reef, a deep reef (trout, that lake trout were 1–2 m above bottom, and that spawning took place over specific habitat. Lake trout density exhibited a high degree of spatial structure (autocorrelation) up to a range of ~190 m, and highest lake trout and egg densities occurred over rough substrates (rubble and cobble) at the shallowest depths sampled (36–42 m). Mean lake trout density in the area surveyed (~2190 ha) was 5.8 fish/ha and the area surveyed contained an estimated 9500–16,000 large lake trout. Spatial aggregation in lake trout densities, similarity of depths and substrates at which high lake trout and egg densities occurred, and relatively low uncertainty in the lake trout density estimate indicate that acoustic sampling can be a useful complement to other sampling tools used in lake trout restoration research.

  10. Live-trapping and handling brown bear

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This paper reports techniques developed to live trap and handle brown bears on the Kodiak National Wildlife Refuge. The brown bears (Ursus middendorffi) on the...

  11. Browns Park NWR Water Use Report- 1999

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report contains locations and water use at Browns Park NWR for 1999. A basic introduction highlighting the region that Browns Park NWR is a part of and the...

  12. Browns Park NWR Water Use Report- 2000

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report contains locations and water use at Browns Park NWR for 2000. A basic introduction highlighting the region that Browns Park NWR is a part of and the...

  13. Umatilla River Basin Anadromous Fish Habitat Enhancement Project : 1993 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, R. Todd

    1993-04-01

    The Umatilla Basin Anadromous Fish Habitat Enhancement Project is funded under the Northwest Power Planning Council's Columbia River Basin Fish and Wildlife Program Measure 704 (d) (1) 34.02 and targets the improvement of water quality and restoration of riparian areas, holding, spawning and rearing habitats of steelhead, spring and fall chinook and coho salmon. The project focused on implementing instream and riparian habitat improvements on private lands on the Umatilla Indian Reservation (hereafter referred to as Reservation) from April 1, 1988 to March 31, 1992. These efforts resulted in enhancement of the lower 1/4 mile of Boston Canyon Creek, the lower 4 river miles of Meacham Creek and 3.2 river miles of the Umatilla River (downstream of the Meacham Creek confluence upstream to the Reservation East Boundary). In 1993, the project shifted emphasis to a comprehensive watershed approach consistent with other basin efforts and began to identify upland and riparian watershed-wide causative factors impacting fisheries habitat and natural fisheries production capabilities throughout the Umatilla River Watershed. Maintenance of existing habitat improvement projects was included under this comprehensive approach. Maintenance of existing gravel traps, instream and bank stabilization structures was required within project areas during the reporting period due to spring flooding damage and high bedload movement. Maintenance activities were completed between river mile (RM) 0.0 and RM 0.25 Boston Canyon Creek, between RM 0.0 and RM 4 Meacham Creek and between RM 78.5 and RM 79 Umatilla River. Habitat enhancement areas were seeded with native grass, legume, shrub and wildflower mixes and planted with willow cuttings to assist in floodplain recovery, stream channel stability and filtering of sediments during high flow periods. Water quality monitoring continued for temperature and turbidity throughout the upper Umatilla River Watershed. Survey of cross sections and

  14. 21 CFR 184.1120 - Brown algae.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Brown algae. 184.1120 Section 184.1120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1120 Brown algae. (a) Brown algae are seaweeds of the species...

  15. Bull Trout Life History, Genetics, Habitat Needs, and Limiting Factors in Central and Northeast Oregon. Annual Report 1996.

    Energy Technology Data Exchange (ETDEWEB)

    Bellerud, Blane L.; Gunckel, Stephanie; Hemmingsen, Alan R.; Buchanan, David V.; Howell, Philip J.

    1997-10-01

    This study is part of a multi-year research project studying aspects of bull trout life history, ecology and genetics. This report covers the activities of the project in 1996. Results and analysis are presented in the following five areas: (1) analysis of the genetic structure of Oregon bull trout populations; (2) distribution and habitat use of bull trout and brook trout in streams containing both species; (3) bull trout spawning surveys; (4) summary and analysis of historical juvenile bull trout downstream migrant trap catches in the Grande Ronde basin; and (5) food habits and feeding behavior of bull trout alone and in sympatry with brook trout.

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

    Data.gov (United States)

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

  17. Bull Trout Distribution, Pacific Northwest (updated March, 2006)

    Data.gov (United States)

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

  18. Brook Trout Distribution, Pacific Northwest (updated March, 2006)

    Data.gov (United States)

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

  19. Yellowstone Cutthroat Trout Distribution, Pacific Northwest (updated March, 2006)

    Data.gov (United States)

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

  20. Rainbow Trout Distribution, Pacific Northwest (updated March, 2006)

    Data.gov (United States)

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

  1. Redband Trout Distribution, Pacific Northwest (updated March, 2006)

    Data.gov (United States)

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

  2. Lahontan Cutthroat Trout Distribution, Pacific Northwest (updated March, 2006)

    Data.gov (United States)

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

  3. Species status assessment report for the Rio Grande cutthroat trout

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Rio Grande cutthroat trout (Oncorhynchus clarkii virginalis) lives in high elevation, coldwater streams in New Mexico and southern Colorado. It is a subspecies...

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

    Data.gov (United States)

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

  5. ERM booster vaccination of Rainbow trout using diluted bacterin

    DEFF Research Database (Denmark)

    Schmidt, Jacob Günther; Henriksen, Niels H.; Buchmann, Kurt

    2016-01-01

    Enteric Red Mouth Disease ERM caused by Yersinia ruckeri infection is associated with morbidity and mortality in salmonid farming but immersion vaccination of fry may confer some protection for a number of months. Revaccination of rainbow trout, even by use of diluted ERM immersion vaccine, can...... under laboratory conditions extend the protection period. The present field study investigated the applicability of the method under practical farming conditions (freshwater earth ponds supplied by stream water). Primary immersion vaccination of trout (3–4 g) for 30 s in Y. ruckeri bacterin (diluted 1......:10) in April 2015 was followed 3 months later (July 2015) by 1 h bathing of rainbow trout in bacterin (diluted 1:650 or 1:1700) in order to evaluate if this time saving vaccination methodology can improve immunity and protection. Trout were subjected in farms to natural Y. ruckeri exposure in June and July...

  6. Great Smoky Mountains National Park Brook Trout Genetics

    Data.gov (United States)

    National Park Service, Department of the Interior — Great Smoky Mountains National Park (GRSM) is committed to monitoring ecological and evolutionary functions and processes of park ecosystems. Brook trout...

  7. Food Intake and Feed Conversion Ratios in Abant Trout (Salmo trutta abanticus T., 1954) and Rainbow Trout (Oncorhynchus mykiss W., 1792) in Pond Culture

    OpenAIRE

    UYSAL, İrfan

    2002-01-01

    This study was carried out at DSI-Gölköy Fish Production Station in Bolu and lasted for 350 days. Food consumption (FC) and feed conversion ratios (FCR) in Abant and rainbow trout in pond culture were compared. Abant trout larvae obtained from eggs of wild Abant trout broodstocks in Lake Abant and rainbow trout larvae obtained from eggs of the cultured broodstocks in Gölköy Fish Production Station were used in this study. Trial I involved 4 groups (2 Abant and rainbow trout experimental gr...

  8. Comparison of the Growth Performance and Mortality in Abant Trout (Salmo trutta abanticus Tortonese, 1954) and Rainbow Trout (Oncorhynchus mykiss Walbaum, 1792) under Farming Conditions

    OpenAIRE

    UYSAL, İrfan

    2002-01-01

    This experiment was conducted between 15th February 2000 (day 1) and 31st January 2001 (day 350) at the DSI-Gölköy Fish Production Station, Bolu (Turkey). Abant trout larvae obtained from eggs of wild Abant trout broodstocks in Lake Abant and rainbow trout larvae obtained from eggs of the hatchery broodstocks in Gölköy Fish Production Station were used. Trials I and II involved eight groups (four Abant and rainbow trout experimental groups, and four Abant and rainbow trout parallel groups). A...

  9. Effects of trout bradykinin on the motility of the trout stomach and intestine: evidence for a receptor distinct from mammalian B1 and B2 subtypes

    OpenAIRE

    Jensen, Jorgen; J. Michael Conlon

    1997-01-01

    Trout bradykinin ([Arg0,Trp5,Leu8]-bradykinin; trout BK), recently isolated from kallikrein-treated trout plasma, produced sustained and concentration-dependent contractions of isolated longitudinal muscle from rainbow trout stomach (pD2=7.01±0.03) and proximal small intestine (pD2=7.37±0.07). The maximum responses were 85±2% (stomach) and 101±35% (intestine) of the corresponding responses to 10−5 M acetylcholine. Strips of circular smooth muscle from trout stomach and intestine did not contr...

  10. Anadromous char as an alternate food choice to marine animals: A synthesis of Hg concentrations, population features and other influencing factors

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Marlene S., E-mail: marlene.evans@ec.gc.ca [Environment Canada, Water Science and Technology Directorate, 11 Innovation Blvd., Saskatoon SK S7N 3H5 (Canada); Muir, Derek C.G. [Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Rd., Burlington, ON L7R 4A6 (Canada); Keating, Jonathan [Environment Canada, Water Science and Technology Directorate, 11 Innovation Blvd., Saskatoon SK S7N 3H5 (Canada); Wang, Xiaowa [Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Rd., Burlington, ON L7R 4A6 (Canada)

    2015-03-15

    This study was conducted to confirm sporadic measurements made over the late 1970s to the early 1990s which determined that mercury (Hg) concentrations were low in anadromous char across Arctic and subarctic Canada including northern Québec and Labrador. Over 2004–2013, anadromous char populations across northern Canada were investigated at 20 sites for Hg concentrations and life history characteristics. Hg concentrations were extremely low in anadromous char muscle, typically < 0.05 μg/g (wet weight) and, at each location, generally increased with fish length, age and nitrogen isotope (δ{sup 15}N) ratio and decreased with condition factor and %lipid; correlations with carbon isotope (δ{sup 13}C) ratio were inconsistent. Location and year were significant variables influencing Hg concentrations over the study area; longitude and latitude also were significant influencing variables. Char length, weight, age, condition factor and lipid content explained additional variance. A tendency towards higher Hg concentrations with increasing latitude may be partially related to decreasing growth of char towards the north. However, Hg concentrations in char were positively correlated with growth rates suggesting that Hg concentrations in char also were higher in the more productive study areas, including to the west where mainland riverine inputs of terrestrial carbon, nutrients, and Hg were greater. The data base for assessing time trends in char was limited by the small number of years investigated at most locations, variable fish size across years, small sample size, etc. Where temporal trends were detected, they were of increase on the long term (1970s, 1980s or early 1990s to the present) but of decrease on the short term (early 2000s to present) with Nain (Labrador) showing the converse pattern. Higher Hg concentrations were also related to lower condition factor and cooler springs. Hg concentrations in anadromous char are compared with other terrestrial, aquatic

  11. Anadromous char as an alternate food choice to marine animals: A synthesis of Hg concentrations, population features and other influencing factors

    International Nuclear Information System (INIS)

    This study was conducted to confirm sporadic measurements made over the late 1970s to the early 1990s which determined that mercury (Hg) concentrations were low in anadromous char across Arctic and subarctic Canada including northern Québec and Labrador. Over 2004–2013, anadromous char populations across northern Canada were investigated at 20 sites for Hg concentrations and life history characteristics. Hg concentrations were extremely low in anadromous char muscle, typically < 0.05 μg/g (wet weight) and, at each location, generally increased with fish length, age and nitrogen isotope (δ15N) ratio and decreased with condition factor and %lipid; correlations with carbon isotope (δ13C) ratio were inconsistent. Location and year were significant variables influencing Hg concentrations over the study area; longitude and latitude also were significant influencing variables. Char length, weight, age, condition factor and lipid content explained additional variance. A tendency towards higher Hg concentrations with increasing latitude may be partially related to decreasing growth of char towards the north. However, Hg concentrations in char were positively correlated with growth rates suggesting that Hg concentrations in char also were higher in the more productive study areas, including to the west where mainland riverine inputs of terrestrial carbon, nutrients, and Hg were greater. The data base for assessing time trends in char was limited by the small number of years investigated at most locations, variable fish size across years, small sample size, etc. Where temporal trends were detected, they were of increase on the long term (1970s, 1980s or early 1990s to the present) but of decrease on the short term (early 2000s to present) with Nain (Labrador) showing the converse pattern. Higher Hg concentrations were also related to lower condition factor and cooler springs. Hg concentrations in anadromous char are compared with other terrestrial, aquatic and marine

  12. SuchThatCast Episode 3: J.D. Trout

    OpenAIRE

    Søraker, J.H.

    2012-01-01

    SuchThatCast goes mobile in the third episode, as I interview J.D. Trout on the appr. 2 hour train ride between Enschede and Schiphol airport. Trout received his PhD in Philosophy at Cornell University and is currently Professor of Philosophy and Psychology at Loyola University Chicago. He was recently awarded the prestigious Phi Beta Kappa Romanell Professorship for 2012-13. His chief interests include the nature of scientific explanation, the psychology of human judgment, scientific realism...

  13. Evolutionary Genetics of Rainbow Trout, Parasalmo gairdnerii (Richardson)

    OpenAIRE

    Berg, William J.

    1987-01-01

    Starch-gel electrophoresis was used to obtain allozyme data from 114 populations of rainbow-series trout. Seventy-three alleles were segregating at 24 genetic loci. An additional seven loci were monomorphic in all populations. Eight genetically discrete intraspecific population-groups were identified and formal nomenclatural recognition of their subspecific status was suggested. The widespread coastal rainbow trout subspecies, Parasalmo gairdnerii gairdnerii was found to have higher levels of...

  14. On the Formation of Brown Dwarfs

    CERN Document Server

    Jiang, I G; Lin, D N C; Jiang, Ing-Guey

    2004-01-01

    The observational properties of brown dwarfs pose challenges to the theory of star formation. Because their mass is much smaller than the typical Jeans mass of interstellar clouds, brown dwarfs are most likely formed through secondary fragmentation processes, rather than through the direct collapse of a molecular cloud core. In order to prevent substantial post-formation mass accretion, young brown dwarfs must leave the high density formation regions in which they form. We propose here that brown dwarfs are formed in the circumbinary disks. Through post-formation dynamical interaction with their host binary stars, young brown dwarfs are either scattered to large distance or removed, with modest speed, from their cradles.

  15. Virulence of Flavobacterium columnare genomovars in rainbow trout Oncorhynchus mykiss.

    Science.gov (United States)

    Evenhuis, Jason P; LaFrentz, Benjamin R

    2016-08-01

    Flavobacterium columnare is the causative agent of columnaris disease and is responsible for significant economic losses in aquaculture. F. columnare is a Gram-negative bacterium, and 5 genetic types or genomovars have been described based on restriction fragment length polymorphism of the 16S rRNA gene. Previous research has suggested that genomovar II isolates are more virulent than genomovar I isolates to multiple species of fish, including rainbow trout Oncorhynchus mykiss. In addition, improved genotyping methods have shown that some isolates previously classified as genomovar I, and used in challenge experiments, were in fact genomovar III. Our objective was to confirm previous results with respect to genomovar II virulence, and to determine the susceptibility of rainbow trout to other genomovars. The virulence of 8 genomovar I, 4 genomovar II, 3 genomovar II-B, and 5 genomovar III isolates originating from various sources was determined through 3 independent challenges in rainbow trout using an immersion challenge model. Mean cumulative percent mortality (CPM) of ~49% for genomovar I isolates, ~1% for genomovar II, ~5% for the II-B isolates, and ~7% for the III isolates was observed. The inability of genomovar II isolates to produce mortalities in rainbow trout was unanticipated based on previous studies, but may be due to a number of factors including rainbow trout source and water chemistry. The source of fish and/or the presence of sub-optimal environment may influence the susceptibility of rainbow trout to different F. columnare genomovars. PMID:27503917

  16. Predation on lake trout eggs and fry: A modeling approach

    Science.gov (United States)

    Savino, Jacqueline F.; Hudson, Patrick L.; Fabrizio, Mary C.; Bowen, Charles A.

    1999-01-01

    A general model was developed to examine the effects of multiple predators on survival of eggs and fry of lake trout, Salvelinus namaycush, associated with spawning reefs. Three kinds of predation were simulated: epibenthic egg predators consuming eggs on the substrate surface during spawning, interstitial egg predators that can move in rocky substrate and consume incubating eggs, and fry predators. Also simulated was the effect of water temperature on predation rates. The model predicted that interstitial predation on eggs accounted for most (76 to 81%) of the predation on early life history stages of lake trout; epibenthic egg predation (12 to 19%) and fry predation (0 to 12%) had less effect on lake trout survival. Initial predation conditions chosen for the model were: epibenthic egg predation peaked at 2 eggs/mA?/d over 30 d, insterstitial egg predation at 2 eggs/mA?/d over 180 d, and fry predation at 1 fry/mA?/d over 60 d. With a starting egg density of 100 eggs/mA? and initial predation conditions, no lake trout were estimated to survive to swim-up. At egg densities of 250 eggs/mA?, 36% of the lake trout survived. At the highest egg densities examined, 500 to 1,000 eggs/mA?, estimated survival increased to about 70 to 80%. Simulated survival rates of lake trout decreased dramatically as predation rate increased but were not as sensitive to increases in the duration of predation.

  17. Conservation of native Pacific trout diversity in western North America

    Science.gov (United States)

    Penaluna, Brooke E.; Abadía-Cardoso, Alicia; Dunham, Jason; García de León, Francisco J; Gresswell, Robert E.; Luna, Arturo Ruiz; Taylor, Eric B.; Shepard, Bradley B.; Al-Chokhachy, Robert K.; Muhlfeld, Clint C.; Bestgen, Kevin R.; Rogers, Kevin H.; Escalante, Marco A; Keeley, Ernest R; Temple, Gabriel; Williams, Jack E.; Matthews, Kathleen; Pierce, Ron; Mayden, Richard L.; Kovach, Ryan; Garza, John Carlos; Fausch, Kurt D.

    2016-01-01

    Pacific trout Oncorhynchus spp. in western North America are strongly valued in ecological, socioeconomic, and cultural views, and have been the subject of substantial research and conservation efforts. Despite this, the understanding of their evolutionary histories, overall diversity, and challenges to their conservation is incomplete. We review the state of knowledge on these important issues, focusing on Pacific trout in the genus Oncorhynchus. Although most research on salmonid fishes emphasizes Pacific salmon, we focus on Pacific trout because they share a common evolutionary history, and many taxa in western North America have not been formally described, particularly in the southern extent of their ranges. Research in recent decades has led to the revision of many hypotheses concerning the origin and diversification of Pacific trout throughout their range. Although there has been significant success at addressing past threats to Pacific trout, contemporary and future threats represented by nonnative species, land and water use activities, and climate change pose challenges and uncertainties. Ultimately, conservation of Pacific trout depends on how well these issues are understood and addressed, and on solutions that allow these species to coexist with a growing scope of human influences.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2002-08-01

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

  19. Anadromous char as an alternate food choice to marine animals: a synthesis of Hg concentrations, population features and other influencing factors.

    Science.gov (United States)

    Evans, Marlene S; Muir, Derek C G; Keating, Jonathan; Wang, Xiaowa

    2015-03-15

    This study was conducted to confirm sporadic measurements made over the late 1970s to the early 1990 s which determined that mercury (Hg) concentrations were low in anadromous char across Arctic and subarctic Canada including northern Québec and Labrador. Over 2004-2013, anadromous char populations across northern Canada were investigated at 20 sites for Hg concentrations and life history characteristics. Hg concentrations were extremely low in anadromous char muscle, typically factor and %lipid; correlations with carbon isotope (δ(13)C) ratio were inconsistent. Location and year were significant variables influencing Hg concentrations over the study area; longitude and latitude also were significant influencing variables. Char length, weight, age, condition factor and lipid content explained additional variance. A tendency towards higher Hg concentrations with increasing latitude may be partially related to decreasing growth of char towards the north. However, Hg concentrations in char were positively correlated with growth rates suggesting that Hg concentrations in char also were higher in the more productive study areas, including to the west where mainland riverine inputs of terrestrial carbon, nutrients, and Hg were greater. The data base for assessing time trends in char was limited by the small number of years investigated at most locations, variable fish size across years, small sample size, etc. Where temporal trends were detected, they were of increase on the long term (1970s, 1980s or early 1990 s to the present) but of decrease on the short term (early 2000s to present) with Nain (Labrador) showing the converse pattern. Higher Hg concentrations were also related to lower condition factor and cooler springs. Hg concentrations in anadromous char are compared with other terrestrial, aquatic and marine vertebrates in traditional diets. The known information on anadromous char is reviewed including population features, habitat, and harvests. Future Hg

  20. AEROMONAS SALMONICIDA INFECTION IN VACCINATED RAINBOW TROUT

    DEFF Research Database (Denmark)

    Chettri, Jiwan Kumar; Skov, Jakob; Mohammad, Rezkar Jaafar;

    to that of the commercial vaccine with lower side effects as observed by the Speilberg scoring system. Gene expression analysis did not show a clear trend for Th1 or Th2 response in the vaccinated fish. Exposure of fish to saltwater increased the IgT production. Overall, the immune response in vaccinated fish, the side......In vivo testing of any candidate vaccine is influenced by the choice of challenge method and the external environmental conditions. In the present study, a comparative challenge study was performed to evaluate the efficacy of different vaccines against the bacterial pathogen Aeromonas salmonicida...... causing furunculosis. Rainbow trout (Oncorhynchus mykiss) were vaccinated with two trivalent adjuvanted experimental vaccines containing formalin-killed A. salmonicida, Vibrio anguillarum O1 and O2a and a commercial corresponding vaccine (Alpha Ject 3000). Fish were challenged by i.p. injection...

  1. Okanogan Subbasin Water Quality and Quantity Report for Anadromous Fish in 2006.

    Energy Technology Data Exchange (ETDEWEB)

    Colville Tribes, Department of Fish & Wildlife

    2007-12-01

    Fish need water of sufficient quality and quantity in order to survive and reproduce. The list of primary water quality indicators appropriate for monitoring of anadromous fish, as identified by the Upper Columbia Monitoring Strategy, includes: discharge, temperature, dissolved oxygen, pH, turbidity, conductivity, nitrogen, phosphorus and ammonia. The Colville Tribes Fish and Wildlife Department began evaluating these water quality indicators in 2005 and this report represents data collected from October 1, 2005 through September 30, 2006. We collected empirical status and trend data from various sources to evaluate each water quality indicator along the main stem Okanogan and Similkameen Rivers along with several tributary streams. Each water quality indicator was evaluated based upon potential impacts to salmonid survival or productivity. Specific conductance levels and all nutrient indicators remained at levels acceptable for growth, survival, and reproduction of salmon and steelhead. These indicators were also considered of marginal value for monitoring environmental conditions related to salmonids within the Okanogan subbasin. However, discharge, temperature, turbidity, dissolved oxygen and pH in that order represent the water quality indicators that are most useful for monitoring watershed health and habitat changes and will help to evaluate threats or changes related to salmon and steelhead restoration and recovery. On the Okanogan River minimum flows have decreased over the last 12 years at a rate of -28.3CFS/year as measured near the town of Malott, WA. This trend is not beneficial for salmonid production and efforts to reverse this trend should be strongly encouraged. Turbidity levels in Bonaparte and Omak Creek were a concern because they had the highest monthly average readings. Major upland disturbance in the Bonaparte Creek watershed has occurred for decades and agricultural practices within the riparian areas along this creek have lead to major

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

    Directory of Open Access Journals (Sweden)

    Moghadam Hooman K

    2011-07-01

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

  3. Intracellular diffusion restrictions in isolated cardiomyocytes from rainbow trout

    Directory of Open Access Journals (Sweden)

    Birkedal Rikke

    2009-12-01

    Full Text Available Abstract Background Restriction of intracellular diffusion of adenine nucleotides has been studied intensively on adult rat cardiomyocytes. However, their cause and role in vivo is still uncertain. Intracellular membrane structures have been suggested to play a role. We therefore chose to study cardiomyocytes from rainbow trout (Oncorhynchus mykiss, which are thinner and have fewer intracellular membrane structures than adult rat cardiomyocytes. Previous studies suggest that trout permeabilized cardiac fibers also have diffusion restrictions. However, results from fibers may be affected by incomplete separation of the cells. This is avoided when studying permeabilized, isolated cardiomyocytes. The aim of this study was to verify the existence of diffusion restrictions in trout cardiomyocytes by comparing ADP-kinetics of mitochondrial respiration in permeabilized fibers, permeabilized cardiomyocytes and isolated mitochondria from rainbow trout heart. Experiments were performed at 10, 15 and 20°C in the absence and presence of creatine. Results Trout cardiomyocytes hypercontracted in the solutions used for mammalian cardiomyocytes. We developed a new solution in which they retained their shape and showed stable steady state respiration rates throughout an experiment. The apparent ADP-affinity of permeabilized cardiomyocytes was different from that of fibers. It was higher, independent of temperature and not increased by creatine. However, it was still about ten times lower than in isolated mitochondria. Conclusions The differences between fibers and cardiomyocytes suggest that results from trout heart fibers were affected by incomplete separation of the cells. However, the lower ADP-affinity of cardiomyocytes compared to isolated mitochondria indicate that intracellular diffusion restrictions are still present in trout cardiomyocytes despite their lower density of intracellular membrane structures. The lack of a creatine effect indicates that

  4. Assessment of Present Anadromous Fish Production Facilities in the Columbia River Basin, US Fish and Wildlife Hatcheries, Final Report.

    Energy Technology Data Exchange (ETDEWEB)

    Delarm, Michael R.; Smith, Robert Z.

    1990-07-01

    The goal of this report is to document current production practices for hatcheries which rear anadromous fish in the Columbia River Basin and to identify those facilities where production can be increased. A total of 85 hatchery and satellite facilities operated by the Idaho Department of Fish and Game, Oregon Department of Fish and Game, US Fish and Wildlife Service, Washington Department of Wildlife, and Washington Department of Fisheries were evaluated. The years 1985 to 1987 were used in this evaluation. During those years, releases averaged 143,306,596 smolts weighing 7,693,589 pounds. A total of 48 hatchery or satellite facilities were identified as having expansion capability. They were estimated to have the potential for increasing production by an 84,448,000 smolts weighing 4,853,306 pounds. 2 refs., 25 tabs.

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

    OpenAIRE

    Teachout, Emily; Quan, Jennifer

    2001-01-01

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

  6. Microlensing, Brown Dwarfs and GAIA

    CERN Document Server

    Evans, N W

    2014-01-01

    The GAIA satellite can precisely measure the masses of nearby brown dwarfs and lower main sequence stars by the microlensing effect. The scientific yield is maximised if the microlensing event is also followed with ground-based telescopes to provide densely sampled photometry. There are two possible strategies. First, ongoing events can be triggered by photometric or astrometric alerts by GAIA. Second, events can be predicted using known high proper motion stars as lenses. This is much easier, as the location and time of an event can be forecast. Using the GAIA source density, we estimate that the sample size of high proper motion ($>300$ mas yr$^{-1}$) brown dwarfs needed to provide predictable events during the 5 year mission lifetime is surprisingly small, only of the order of a hundred. This is comparable to the number of high proper motion brown dwarfs already known from the work of the UKIDSS Large Area Survey and the all-sky WISE satellite. Provided the relative parallax of the lens and the angular Ein...

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

    Science.gov (United States)

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

    2016-01-01

    Introductions of nonnative species, habitat loss, and stream fragmentation have caused the Bull Trout Salvelinus confluentus to decline throughout much of its native distribution. Consequently, in June 1998, the Bull Trout was listed under the U.S. Endangered Species Act as threatened. The Bull Trout has existed in Lake Pend Oreille and its surrounding tributaries since the last ice age, and the lake once supported a world-renowned Bull Trout fishery. To quantify the current status of the Bull Trout population in Lake Pend Oreille, Idaho, we compared the mean age, growth, maturity, and abundance with reports in a study conducted one decade earlier. Abundance was estimated by mark–recapture for Bull Trout caught in trap nets and gill nets set in Lake Pend Oreille during ongoing suppression netting of Lake Trout S. namaycushin 2007–2008. Bull Trout sampled in 2006–2008 were used to estimate age structure, survival, growth, and maturity. Estimated Bull Trout abundance was similar to that estimated one decade earlier in Lake Pend Oreille. Bull Trout residing in Lake Pend Oreille between 2006 and 2008 were between ages 4 and 14 years; their growth was fastest between ages 1 and 2 and slowed thereafter. Male and female Bull Trout matured at a similar age, but females grew faster than males, thereby maturing at a larger size. Our findings suggest that management has effectively addressed current threats to increase the likelihood of long-term persistence of the Bull Trout population in Lake Pend Oreille.

  8. Exploring trends, causes, and consequences of declining lipids in Lake Superior lake trout

    Science.gov (United States)

    The ability of lake trout to forage in deepwater habitats is facilitated by high lipid content, which affords buoyancy. In Lake Superior, lean lake trout historically occupied depths < 80 m, and siscowet lake trout occupied depths > 80 m. Siscowets have been known f...

  9. 77 FR 62500 - Peabody Trout Creek Reservoir LLC; Notice of Intent To File License Application, Filing of Pre...

    Science.gov (United States)

    2012-10-15

    ... Energy Regulatory Commission Peabody Trout Creek Reservoir LLC; Notice of Intent To File License...: Peabody Trout Creek Reservoir LLC. e. Name of Project: Trout Creek Reservoir Hydroelectric Project. f. Location: On Trout Creek, 15 miles southwest of Steamboat Springs, Colorado. The project occupies 4.3...

  10. Evaluation of an Unsuccessful Brook Trout Electrofishing Removal Project in a Small Rocky Mountain Stream.

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Kevin A.; Lamansky, Jr., James A.; Schill, Daniel J.

    2006-01-26

    In the western United States, exotic brook trout Salvelinus fontinalis frequently have a deleterious effect on native salmonids, and biologists often attempt to remove brook trout from streams by means of electrofishing. Although the success of such projects typically is low, few studies have assessed the underlying mechanisms of failure, especially in terms of compensatory responses. A multiagency watershed advisory group (WAG) conducted a 3-year removal project to reduce brook trout and enhance native salmonids in 7.8 km of a southwestern Idaho stream. We evaluated the costs and success of their project in suppressing brook trout and looked for brook trout compensatory responses, such as decreased natural mortality, increased growth, increased fecundity at length, and earlier maturation. The total number of brook trout removed was 1,401 in 1998, 1,241 in 1999, and 890 in 2000; removal constituted an estimated 88% of the total number of brook trout in the stream in 1999 and 79% in 2000. Although abundance of age-1 and older brook trout declined slightly during and after the removals, abundance of age-0 brook trout increased 789% in the entire stream 2 years after the removals ceased. Total annual survival rate for age-2 and older brook trout did not decrease during the removals, and the removals failed to produce an increase in the abundance of native redband trout Oncorhynchus mykiss gairdneri. Lack of a meaningful decline and unchanged total mortality for older brook trout during the removals suggest that a compensatory response occurred in the brook trout population via reduced natural mortality, which offset the removal of large numbers of brook trout. Although we applaud WAG personnel for their goal of enhancing native salmonids by suppressing brook trout via electrofishing removal, we conclude that their efforts were unsuccessful and suggest that similar future projects elsewhere over such large stream lengths would be costly, quixotic enterprises.

  11. Sequential presentation of bilateral Brown syndrome.

    Science.gov (United States)

    Sekeroğlu, Hande Taylan; Türkçüoğlu, Peykan; Sanaç, Ali Şefik; Sener, Emin Cumhur

    2012-04-01

    Brown syndrome, characterized by a limitation of elevation in adduction and positive forced duction testing, is usually unilateral but occurs bilaterally in 10% of all cases. It may present as a congenital condition in one eye and develop in the other eye with no apparent cause. We present a case of bilateral Brown syndrome in which the right eye became involved within 1 year of surgery on the left eye for congenital Brown syndrome.

  12. Surprising Legacies of Brown v. Board

    OpenAIRE

    Minow, Martha Louise

    2014-01-01

    Perhaps the most powerful legacy of Brown v. Board is this: opponents in varied political battles fifty years later each claim ties to the decision and its meaning. So although the analogy between Brown and same-sex marriage has divided Black clergy, each side vies to inherit the civil rights heritage. President George W. Bush invoked Brown in opposing race-conscious college admission practices. The success of Brown in reshaping the moral landscape has been so profound that I fear we do not f...

  13. BROWN TUMOR OF THE FACIAL BONES

    Directory of Open Access Journals (Sweden)

    Violeta Trandafir

    2010-11-01

    Full Text Available Brown tumor arises as a direct result of the effect of parathyroid hormone on bone tissue in some patients with hyperparathyroidism. The lesion localizes in areas of intense bone resorbtion, and the bone defect becomes filled with fibroblastic tissue that can deform the bone and simulate a neoplastic process. Brown tumors can affect the mandible, maxilla, clavicle, ribs and pelvic bones. Most patients with hyperparathyroidism are asymptomatic. Skeletal changes may represent the first manifestations of the disease. Radiologically, brown tumor in the jaws presents as a well-defined radiolucent osteolytic lesion, making it hard to differentiate it from other maxillary expansive lesions that can present with a similar imaging. Brown tumors exhibit no pathognomonic histologic changes. Differentiating between a brown tumor and other giant-cell tumors may be very difficult, even with histology. A final diagnosis can be defined only by evaluating the radiological findings with histopathological, laboratory and clinical data. At present, brown tumor is considered as a reparative cellular process rather than a real neoplasia. This phenomenon is considered as pathognomonic of hyperparathyroidism secondary to renal failure, especially in patients on long-term hemodialysis. The initial treatment of brown tumor involves control of hyperparathyroidism, regardless of whether it is primary or secondary. The clinical management of brown tumor aims primarily to reduce the elevated parathyroid hormone levels by pharmacological treatment. Surgical treatment is reserved to nonresponders or to patients with painful symptomatology or alteration of normal function. Brown tumor can recur if hyperparathyroidism persists or recurs.

  14. The Engrailed-1 Gene Stimulates Brown Adipogenesis

    Directory of Open Access Journals (Sweden)

    Chuanhai Zhang

    2016-01-01

    Full Text Available As a thermogenic organ, brown adipose tissue (BAT has received a great attention in treating obesity and related diseases. It has been reported that brown adipocyte was derived from engrailed-1 (EN1 positive central dermomyotome. However, functions of EN1 in brown adipogenesis are largely unknown. Here we demonstrated that EN1 overexpression increased while EN1 knockdown decreased lipid accumulation and the expressions of key adipogenic genes including PPARγ2 and C/EBPα and mitochondrial OXPHOS as well as BAT specific marker UCP1. Taken together, our findings clearly indicate that EN1 is a positive regulator of brown adipogenesis.

  15. Brown Fat and Browning for the Treatment of Obesity and Related Metabolic Disorders

    Directory of Open Access Journals (Sweden)

    So Hun Kim

    2016-02-01

    Full Text Available Brown fat is a specialized fat depot that can increase energy expenditure and produce heat. After the recent discovery of the presence of active brown fat in human adults and novel transcription factors controlling brown adipocyte differentiation, the field of the study of brown fat has gained great interest and is rapidly growing. Brown fat expansion and/or activation results in increased energy expenditure and a negative energy balance in mice and limits weight gain. Brown fat is also able to utilize blood glucose and lipid and results in improved glucose metabolism and blood lipid independent of weight loss. Prolonged cold exposure and beta adrenergic agonists can induce browning of white adipose tissue. The inducible brown adipocyte, beige adipocyte evolving by thermogenic activation of white adipose tissue have different origin and molecular signature from classical brown adipocytes but share the characteristics of high mitochondria content, UCP1 expression and thermogenic capacity when activated. Increasing browning may also be an efficient way to increase whole brown fat activity. Recent human studies have shown possibilities that findings in mice can be reproduced in human, making brown fat a good candidate organ to treat obesity and its related disorders.

  16. Enzymatic Browning: a practical class

    Directory of Open Access Journals (Sweden)

    Maria Teresa Pedrosa Silva Clerici

    2014-10-01

    Full Text Available This paper presents a practical class about the enzymes polyphenol oxidases, which have been shown to be responsible for the enzymatic browning of fruits and vegetables. Vegetables samples were submitted to enzymatic inactivation process with chemical reagents, as well as by bleaching methods of applying heat by conventional oven and microwave oven. Process efficiency was assessed qualitatively by both observing the guaiacol peroxidase activity and after the storage period under refrigeration or freezing. The practical results obtained in this class allow exploring multidisciplinary knowledge in food science, with practical applications in everyday life.

  17. The marine life of sea trout (Salmo trutta)

    DEFF Research Database (Denmark)

    Del Villar, Diego

    -smolts as well as on the fish returning to freshwater after the marine stage. The results of my experiments increase the current knowledge of specific behavioural traits that sea trout displays during their marine life. Additionally, it provides new information on the early and late marine survival which......During my PhD. research project I have studied the marine migratory behaviour and survival of wild sea trout (Salmo trutta L.) juveniles when moving from freshwater to saltwater (i.e. smolts/post-smolts) in two different fjord systems. These studies are focused on the initial marine stage of post...... is needed for comprehensive management of sea trout populations in the area. The principal method used was telemetry (acoustic and PIT-telemetry) which enable studying migratory patterns of fish in the fjord (i.e. acoustic telemetry) and detecting the transitions from the marine to the riverine environments...

  18. Movement Patterns and Multi-Scale Factors That Influence Exotic Brook Trout And Endemic Bonneville Cutthroat Trout Distribution And Abundance In The Mill Creek Drainage, Utah

    OpenAIRE

    Nadolski, Benjamin Keith

    2008-01-01

    Introduced brook trout (Salvelinus fontinalis) are implicated as a primary factor leading to the decline in distribution and abundance of native cutthroat trout (Oncorhynchus clarkii). However, not all introductions are successful, suggesting local conditions influence the success of invasions. Therefore, I sought to determine the multi-scale factor(s) that influence brook trouts’ invasion success of native Bonneville cutthroat trout (Oncorhynchus clarkii utah) habitats in Mill Creek, Utah. I...

  19. Chromosome rearrangements, recombination suppression, and limited segregation distortion in hybrids between Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri) and rainbow trout (O. mykiss)

    OpenAIRE

    Carl O Ostberg; Hauser, Lorenz; Pritchard, Victoria L; Garza, John C; Naish, Kerry A.

    2013-01-01

    Background Introgressive hybridization is an important evolutionary process that can lead to the creation of novel genome structures and thus potentially new genetic variation for selection to act upon. On the other hand, hybridization with introduced species can threaten native species, such as cutthroat trout (Oncorhynchus clarkii) following the introduction of rainbow trout (O. mykiss). Neither the evolutionary consequences nor conservation implications of rainbow trout introgression in cu...

  20. Investigations of Bull Trout (Salvelinus Confluentus), Steelhead Trout (Oncorhynchus Mykiss), and Spring Chinook Salmon (O. Tshawytscha) Interactions in Southeast Washington Streams. Final Report 1992.

    Energy Technology Data Exchange (ETDEWEB)

    Underwood, Keith D.

    1995-01-01

    The goal of this two year study was to determine if supplementation with hatchery reared steelhead trout (Oncorhynchus mykiss) and spring chinook salmon (O. tshawytscha) negatively impacted wild native bull trout (Salvelinus confluentus) through competitive interactions. Four streams with varying levels of fish supplementation activity were sampled in Southeast Washington. Tasks performed during this study were population density, relative abundance, microhabitat utilization, habitat availability, diet analysis, bull trout spawning ground surveys, radio telemetry of adult bull trout, and growth analysis. Results indicate that bull trout overlapped geographically with the supplemented species in each of the study streams suggesting competition among species was possible. Within a stream, bull trout and the supplemented species utilized dissimilar microhabitats and microhabitat utilization by each species was the same among streams suggesting that there was no shifts in microhabitat utilization among streams. The diet of bull trout and O. mykiss significantly overlapped in each of the study streams. The stream most intensely supplemented contained bull trout with the slowest growth and the non-supplemented stream contained bull trout with the fastest growth. Conversely, the stream most intensely supplemented contain steelhead with the fastest growth and the non-supplemented stream contained steelhead with the slowest growth. Growth indicated that bull trout may have been negatively impacted from supplementation, although other factors may have contributed. At current population levels, and current habitat quantity and quality, no impacts to bull trout as a result of supplementation with hatchery reared steelhead trout and spring chinook salmon were detected. Project limitations and future research recommendations are discussed.

  1. Investigations of bull trout (Salvelinus confluentus), steelhead trout (Oncorhynchus mykiss), and spring chinook salmon (O. tshawytscha) interactions in Southeast Washington streams. Final report 1992

    International Nuclear Information System (INIS)

    The goal of this two year study was to determine if supplementation with hatchery reared steelhead trout (Oncorhynchus mykiss) and spring chinook salmon (O. tshawytscha) negatively impacted wild native bull trout (Salvelinus confluentus) through competitive interactions. Four streams with varying levels of fish supplementation activity were sampled in Southeast Washington. Tasks performed during this study were population density, relative abundance, microhabitat utilization, habitat availability, diet analysis, bull trout spawning ground surveys, radio telemetry of adult bull trout, and growth analysis. Results indicate that bull trout overlapped geographically with the supplemented species in each of the study streams suggesting competition among species was possible. Within a stream, bull trout and the supplemented species utilized dissimilar microhabitats and microhabitat utilization by each species was the same among streams suggesting that there was no shifts in microhabitat utilization among streams. The diet of bull trout and O. mykiss significantly overlapped in each of the study streams. The stream most intensely supplemented contained bull trout with the slowest growth and the non-supplemented stream contained bull trout with the fastest growth. Conversely, the stream most intensely supplemented contain steelhead with the fastest growth and the non-supplemented stream contained steelhead with the slowest growth. Growth indicated that bull trout may have been negatively impacted from supplementation, although other factors may have contributed. At current population levels, and current habitat quantity and quality, no impacts to bull trout as a result of supplementation with hatchery reared steelhead trout and spring chinook salmon were detected. Project limitations and future research recommendations are discussed

  2. BACTERIAL FLORA OF RAINBOW TROUT LARVAE AND FRY (ONCORHYNCHUS MYKISS

    Directory of Open Access Journals (Sweden)

    Damir Kapetanović

    2003-09-01

    Full Text Available There are no information in available literature about the structure of bacterial flora in rainbow trout larvae and fry in the first days of their lives. The objective of our work has been to follow bacteroflora between the third and the eighth week of their lives. During 35 days of experiment bacteroflora of rainbow trout has been examined, along with following physico–chemical characteristics of water quality as well as it’s influence on health. Samples for bacteriological examination were taken from gill, heart and kidney areas and innoculated on the plates. Bacterial colonies were examined macroscopically, slides with Gram staining, and afterwords biochemical tests were performed. For identification, APILAB Plus programme (bio Mérieux, France was used. Bacterial population of rainbow trout larvae and fry changed in dependence with their age. Physico–chemical characteristics of water ranged within optimal values. Most of bacterial colonies originated from gill isolates (64,4 %, than from heart (21,8 % and kidney areas (13,8 %. The bacterial flora of larvae in incubator was composed mostly of Gram–positive bacteria (75,1 %, genera: Renibacterium (25 %, Lactobacillus (16,7 %, Staphilococcus (16,7 % and Corynebacterium (16,7 %. The transfer of larvae from incubator into the pools resulted in reducing bacterial flora (–66,7 % after 45 minute stay in the pool. Gram–negative bacteria, which have been represented in larvae in incubator with low percent (24, 9 %, after the transfer of larvae to the pools became dominant and represented more than 95 % of rainbow trout larvae and fry bacterial flora. Flavobacterium, Acinetobacter and Yersinia were the predominant Gram–negative genera in larvae in incubator, whereas Aeromonas, Pseudomonas, Flavobacterium and Pasteurella were the main isolates from rainbow trout larvae and fry until the end of experiment. Bacterial flora of larvae in incubator mostly consists of Gram–positive bacteria

  3. A first generation integrated map of the rainbow trout genome

    Directory of Open Access Journals (Sweden)

    Tabet-Canale Kamila

    2011-04-01

    Full Text Available Abstract Background Rainbow trout (Oncorhynchus mykiss are the most-widely cultivated cold freshwater fish in the world and an important model species for many research areas. Coupling great interest in this species as a research model with the need for genetic improvement of aquaculture production efficiency traits justifies the continued development of genomics research resources. Many quantitative trait loci (QTL have been identified for production and life-history traits in rainbow trout. An integrated physical and genetic map is needed to facilitate fine mapping of QTL and the selection of positional candidate genes for incorporation in marker-assisted selection (MAS programs for improving rainbow trout aquaculture production. Results The first generation integrated map of the rainbow trout genome is composed of 238 BAC contigs anchored to chromosomes of the genetic map. It covers more than 10% of the genome across segments from all 29 chromosomes. Anchoring of 203 contigs to chromosomes of the National Center for Cool and Cold Water Aquaculture (NCCCWA genetic map was achieved through mapping of 288 genetic markers derived from BAC end sequences (BES, screening of the BAC library with previously mapped markers and matching of SNPs with BES reads. In addition, 35 contigs were anchored to linkage groups of the INRA (French National Institute of Agricultural Research genetic map through markers that were not informative for linkage analysis in the NCCCWA mapping panel. The ratio of physical to genetic linkage distances varied substantially among chromosomes and BAC contigs with an average of 3,033 Kb/cM. Conclusions The integrated map described here provides a framework for a robust composite genome map for rainbow trout. This resource is needed for genomic analyses in this research model and economically important species and will facilitate comparative genome mapping with other salmonids and with model fish species. This resource will also

  4. Comparative bioenergetics modeling of two Lake Trout morphotypes

    Science.gov (United States)

    Kepler, Megan V.; Wagner, Tyler; Sweka, John A.

    2014-01-01

    Efforts to restore Lake Trout Salvelinus namaycush in the Laurentian Great Lakes have been hampered for decades by several factors, including overfishing and invasive species (e.g., parasitism by Sea Lampreys Petromyzon marinus and reproductive deficiencies associated with consumption of Alewives Alosa pseudoharengus). Restoration efforts are complicated by the presence of multiple body forms (i.e., morphotypes) of Lake Trout that differ in habitat utilization, prey consumption, lipid storage, and spawning preferences. Bioenergetics models constitute one tool that is used to help inform management and restoration decisions; however, bioenergetic differences among morphotypes have not been evaluated. The goal of this research was to investigate bioenergetic differences between two actively stocked morphotypes: lean and humper Lake Trout. We measured consumption and respiration rates across a wide range of temperatures (4–22°C) and size-classes (5–100 g) to develop bioenergetics models for juvenile Lake Trout. Bayesian estimation was used so that uncertainty could be propagated through final growth predictions. Differences between morphotypes were minimal, but when present, the differences were temperature and weight dependent. Basal respiration did not differ between morphotypes at any temperature or size-class. When growth and consumption differed between morphotypes, the differences were not consistent across the size ranges tested. Management scenarios utilizing the temperatures presently found in the Great Lakes (e.g., predicted growth at an average temperature of 11.7°C and 14.4°C during a 30-d period) demonstrated no difference in growth between the two morphotypes. Due to a lack of consistent differences between lean and humper Lake Trout, we developed a model that combined data from both morphotypes. The combined model yielded results similar to those of the morphotype-specific models, suggesting that accounting for morphotype differences may

  5. Study of rainbow trout neoplasia in the region of Haraz

    OpenAIRE

    Notash, Shahab

    2006-01-01

    This study was carried out in order to determine neoplasia presence in rainbow trout in Haraz area. Neoplasia in various species of fishes including freshwater, brackish water and marine fishes was reported in other countries. But up to now there is no documented report of rainbow trout neoplasia in Iran. The study was performed in 20 farms of Haraz area during 2004-2005. All fishes of each farm firstly were observed in order to any abnormal mass which is suspicious to neoplasia. Besides in o...

  6. Immunity to rhabdoviruses in rainbow trout: the antibody response

    DEFF Research Database (Denmark)

    Lorenzen, Niels; Lapatra, S.E.

    1999-01-01

    occasional detrimental effect on rainbow trout farming. Research efforts have been focused on understanding the mechanisms involved in protective immunity. Several specific and nonspecific cellular and humoral parameters are believed to be involved, but only the antibody response has been characterised in......, have demonstrated that rainbow trout can produce specific and highly functional antibodies that are able to neutralise virus pathogenicity in vitro as well as in vivo. The apparently more restricted antibody response to IHNV and VHSV antigens in fish compared to mammals could possibly be explained by...

  7. Marine Model Trout Farms: developments in marine RAS

    DEFF Research Database (Denmark)

    Pedersen, Per Bovbjerg

    2011-01-01

    . This development and demonstration unit in commercial scale will during the next four years hopefully provide scientific and practical basis and support for further development in coming generations of Marine Model Trout Farms for large salmonids. The unit consist in the recirculation loop of one large fish tank...... will be focussed on rainbow trout production, mimicking the typical Danish net cage farming cycle, where the cages are stocked with fish of 750 – 1,000 g in April/May and all harvested before Christmas weighing some 4 kg/pcs. During these two years important production parameters such as growth-rate, feed...

  8. Kootenai River Fisheries Investigations; Rainbow and Bull Trout Recruitment, 2002-2003 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Walters, Jody P.

    2004-01-01

    Rainbow trout Oncorhynchus mykiss provide the most important sport fishery in the Kootenai River, Idaho, but densities and catch rates are low. Low recruitment is one possible factor limiting the rainbow trout population. Bull trout Salvelinus confluentus also exist in the Kootenai River, but little is known about this population. Research reported here addresses the following objectives for the Kootenai River, Idaho: increase rainbow trout recruitment, identify rainbow and bull trout spawning tributaries and migration timing, establish baseline data on bull trout redd numbers in tributaries, and improve the rainbow trout population size structure. Six adult rainbow trout were moved to spawning habitat upstream of a potential migration barrier on Caboose Creek, but numbers of redds and age-0 out-migrants did not appear to increase relative to a reference stream. Measurements taken on the Moyie River indicated the gradient is inadequate to deliver suitable flows to a proposed rainbow trout spawning channel. Summer water temperatures measured in the Deep Creek drainage sometimes exceeded 24 C, higher than those reported as suitable for rainbow trout. Radio-tagged rainbow trout were located in Boulder Creek during the spring spawning season, and bull trout were located in the Moyie River and O'Brien Creek, Montana in the fall. Bull trout spawning migration timing was related to increases in Kootenai River flows. Bull trout redd surveys documented 19 redds on Boulder Creek and North and South Callahan creeks. Fall 2002 electrofishing showed that the Kootenai River rainbow trout proportional stock density was 54, higher than prior years when more liberal fishing regulations were in effect. Boulder Creek produces the highest number of age-0 rainbow trout out-migrants upstream of Bonners Ferry, but the survival rate of these out-migrants upon reaching the Kootenai River is unknown. Determining juvenile survival rates and sources of mortality could aid management

  9. Isolation of glycoproteins from brown algae.

    OpenAIRE

    Surendraraj, Alagarsamy; Farvin Koduvayur Habeebullah , Sabeena; Jacobsen, Charlotte

    2015-01-01

    The present invention relates to a novel process for the isolation of unique anti-oxidative glycoproteins from the pH precipitated fractions of enzymatic extracts of brown algae. Two brown seaweeds viz, Fucus serratus and Fucus vesiculosus were hydrolysed by using 3 enzymes viz, Alcalase, Viscozyme and Termamyl and the glycoproteins were isolated from these enzyme extracts.

  10. The Indirectness of Young Goodman Brown

    Institute of Scientific and Technical Information of China (English)

    袁臣

    2010-01-01

    Young Goodman Brown is one the best short fictions written by Nathaniel Hawthorne in 1835. The indirectness of the Young Goodman Brown can be seen from the produce, narration and the characteristics of the short fiction. The indirectness of expression or description leaves enough space for readers to understand the theme of the short fiction by themselves.

  11. Isolation of glycoproteins from brown algae

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a novel process for the isolation of unique anti-oxidative glycoproteins from the pH precipitated fractions of enzymatic extracts of brown algae. Two brown seaweeds viz, Fucus serratus and Fucus vesiculosus were hydrolysed by using 3 enzymes viz, Alcalase, Viscozyme...

  12. Microlensing Binaries with Candidate Brown Dwarf Companions

    DEFF Research Database (Denmark)

    Shin, I.-G; Han, C.; Gould, A.;

    2012-01-01

    Brown dwarfs are important objects because they may provide a missing link between stars and planets, two populations that have dramatically different formation histories. In this paper, we present the candidate binaries with brown dwarf companions that are found by analyzing binary microlensing ...

  13. INCREASE OF METALLOTHIONEIN-IMMUNOPOSITIVE CHLORIDE CELLS IN THE GILLS OF BROWN TROUT AND RAINBOW TROUT AFTER EXPOSURE TO SEWAGE TREATMENT PLANT EFFLUENT. (R826104)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  14. On the Formation of Brown Dwarfs

    CERN Document Server

    Jiang, I G; Lin, D N C; Jiang, Ing-Guey

    2006-01-01

    The observational properties of brown dwarfs pose challenges to the theory of star formation. Because their mass is much smaller than the typical Jeans mass of interstellar clouds, brown dwarfs are most likely formed through secondary fragmentation processes, rather than through the direct collapse of a molecular cloud core. In order to prevent substantial post-formation mass accretion, young brown dwarfs must leave the high density formation regions in which they form. We propose here that brown dwarfs are formed in the optically thin outer regions of circumbinary disks. Through post-formation dynamical interaction with their host binary stars, young brown dwarfs are either scattered to large distance or removed, with modest speed, from their cradles.

  15. Disks, accretion and outflows of brown dwarfs

    CERN Document Server

    Joergens, V; Liu, Y; Pascucci, I; Whelan, E; Alcala, J; Biazzo, K; Costigan, G; Gully-Santiago, M; Henning, Th; Natta, A; Rigliaco, E; Rodriguez-Ledesma, V; Sicilia-Aguilar, A; Tottle, J; Wolf, S

    2012-01-01

    Characterization of the properties of young brown dwarfs are important to constraining the formation of objects at the extreme low-mass end of the IMF. While young brown dwarfs share many properties with solar-mass T Tauri stars, differences may be used as tests of how the physics of accretion/outflow and disk chemistry/dissipation depend on the mass of the central object. This article summarizes the presentations and discussions during the splinter session on 'Disks, accretion and outflows of brown dwarfs' held at the CoolStars17 conference in Barcelona in June 2012. Recent results in the field of brown dwarf disks and outflows include the determination of brown dwarf disk masses and geometries based on Herschel far-IR photometry (70-160 um), accretion properties based on X-Shooter spectra, and new outflow detections in the very low-mass regime.

  16. Parasites as biological tags of marine, freshwater and anadromous fishes in North America from the Tropics to the Arctic.

    Science.gov (United States)

    Marcogliese, David J; Jacobson, Kym C

    2015-01-01

    Parasites have been considered as natural biological tags of marine fish populations in North America for almost 75 years. In the Northwest Atlantic, the most studied species include Atlantic cod (Gadus morhua), Atlantic herring (Clupea harengus) and the redfishes (Sebastes spp.). In the North Pacific, research has centred primarily on salmonids (Oncorhynchus spp.). However, parasites have been applied as tags for numerous other pelagic and demersal species on both the Atlantic and Pacific coasts. Relatively few studies have been undertaken in the Arctic, and these were designed to discriminate anadromous and resident salmonids (Salvelinus spp.). Although rarely applied in fresh waters, parasites have been used to delineate certain fish stocks within the Great Lakes-St Lawrence River basin. Anisakid nematodes and the copepod Sphyrion lumpi frequently prove useful indicators in the Northwest Atlantic, while myxozoan parasites prove very effective on the coast and open seas of the Pacific Ocean. Relative differences in the ability of parasites to discriminate between fish stocks on the Pacific and Atlantic coasts may be due to oceanographic and bathymetric differences between regions. Molecular techniques used to differentiate populations and species of parasites show promise in future applications in the field.

  17. Genetic Structure of Pacific Trout at the Extreme Southern End of Their Native Range.

    Science.gov (United States)

    Abadía-Cardoso, Alicia; Garza, John Carlos; Mayden, Richard L; García de León, Francisco Javier

    2015-01-01

    Salmonid fishes are cold water piscivores with a native distribution spanning nearly the entire temperate and subarctic northern hemisphere. Trout in the genus Oncorhynchus are the most widespread salmonid fishes and are among the most important fish species in the world, due to their extensive use in aquaculture and valuable fisheries. Trout that inhabit northwestern Mexico are the southernmost native salmonid populations in the world, and the least studied in North America. They are unfortunately also facing threats to their continued existence. Previous work has described one endemic species, the Mexican golden trout (O. chrysogaster), and one endemic subspecies, Nelson's trout (O. mykiss nelsoni), in Mexico, but previous work indicated that there is vastly more biodiversity in this group than formally described. Here we conducted a comprehensive genetic analysis of this important group of fishes using novel genetic markers and techniques to elucidate the biodiversity of trout inhabiting northwestern Mexico, examine genetic population structure of Mexican trout and their relationships to other species of Pacific trout, and measure introgression from non-native hatchery rainbow trout. We confirmed substantial genetic diversity and extremely strong genetic differentiation present in the Mexican trout complex, not only between basins but also between some locations within basins, with at least four species-level taxa present. We also revealed significant divergence between Mexican trout and other trout species and found that introgression from non-native rainbow trout is present but limited, and that the genetic integrity of native trout is still maintained in most locations. This information will help to guide effective conservation strategies for this important group of fishes. PMID:26509445

  18. Selective breeding of food sized rainbow trout against Flavobacteriosis

    Science.gov (United States)

    Selective breeding of rainbow trout is an important component of an integrated fish health management program. The current goals of our selective breeding program are to improve disease resistance, growth and survival in a reuse water environment. To improve these traits, data are recorded on thousa...

  19. Selective breeding of food size rainbow trout against Flavobacteriosis

    Science.gov (United States)

    Selective breeding of rainbow trout is an important component of an integrated fish health management program. The current goals of our selective breeding program are to improve disease resistance, growth and survival in a reuse water environment. To improve these traits, data are recorded on thousa...

  20. Estrogenic response of bisphenol A in rainbow trout (Oncorhynchus mykiss)

    DEFF Research Database (Denmark)

    Lindholst, Christian; Pedersen, Knud Ladegaard; Pedersen, Søren Nørby

    2000-01-01

    Bisphenol A (BPA) previously shown to possess xenoestrogenic activities was administered to rainbow trout (Oncorhynchus mykiss) through a continuos flow system. The estrogenic response expressed as the induction of vitellogenin (VTG) synthesis was measured during 12 days of exposure, using a direct...