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1
Álvarez, David, and Eva Garcia-Vazquez. "Maintenance of asymmetric hybridization between Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) via postzygotic barriers and paternal effects." Canadian Journal of Fisheries and Aquatic Sciences 68, no. 4 (April 2011): 593–602. http://dx.doi.org/10.1139/f2011-004.
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At the southern European edge of Atlantic salmon ( Salmo salar ) distribution, all the hybrids found in nature are the product of crosses between female salmon and male brown trout ( Salmo trutta ). By artificially producing reciprocal crosses between salmon and trout, we demonstrate that unidirectional hybridization observed in nature is the result of postzygotic barriers that produce very high mortality rates (95%) in female trout × male salmon hybrids and not the consequence of prezygotic isolation or behavioural differences between the two species. Mortality of female trout × male salmon hybrids mainly occurs during the last phases of development, and a high percentage of these surviving hybrids showed external deformities that could compromise survival in the wild. Another important finding is the existence of paternal factor in embryo development. Using time to midhatch as an indicator of developmental rate, female salmon × male trout hybrids hatched faster than female trout × male salmon hybrids, with both developing at a rate intermediate to the pure crosses. The early emergence of female salmon × male trout hybrids, which have similar survival to pure salmons, could have fitness repercussions, since early emerging fry have a competitive advantage over later emerging fry.
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Bui, Samantha, Elina Halttunen, Agnes M. Mohn, Tone Vågseth, and Frode Oppedal. "Salmon lice evasion, susceptibility, retention, and development differ amongst host salmonid species." ICES Journal of Marine Science 75, no. 3 (December 12, 2017): 1071–79. http://dx.doi.org/10.1093/icesjms/fsx222.
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Abstract With different ecological characteristics amongst salmonid species, their response to parasitic infestation is likely to vary according to their spatial and temporal overlap with the parasite. This study investigated the host–parasite interactions amongst three species of salmonids and the ectoparasitic salmon louse, Lepeophtheirus salmonis. To determine any variation in infestation parameters amongst salmonids, single population groups of Atlantic salmon (Salmo salar), chinook salmon (Onchorhynchus tshawytscha), and previously-infested and naïve sea trout (Salmo trutta) were exposed to a controlled infestation challenge. We found that chinook salmon and both sea trout groups were more susceptible to acquiring lice than Atlantic salmon. Behavioural responses during infestation were more pronounced in Atlantic and chinook salmon. Parasite development was similar in lice attached to Atlantic salmon and sea trout, but hindered on chinook salmon. At 16 days post-infestation, chinook salmon had reduced lice loads to the same level as Atlantic salmon, whilst sea trout retained their lice. These results demonstrate differences in interactions with L. salmonis amongst these species, and highlight the vulnerability of sea trout to infestation.
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Glover, K. A., Ø. Skaala, F. Nilsen, R. Olsen, A. J. Teale, and J. B. Taggart. "Differing susceptibility of anadromous brown trout (Salmo trutta L.) populations to salmon louse (Lepeophtheirus salmonis (Krøyer, 1837)) infection." ICES Journal of Marine Science 60, no. 5 (January 1, 2003): 1139–48. http://dx.doi.org/10.1016/s1054-3139(03)00088-2.
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Abstract Three Norwegian sea trout (Salmo trutta L.) stocks and a farmed Atlantic salmon (Salmo salar L.) stock were challenged with salmon lice (Lepeophtheirus salmonis (Krøyer, 1837)), in a “common garden” experiment. Sea trout from the River Guddal exhibited a significantly lower level of infection, as measured by louse abundance and louse density, than other stocks. In addition, salmon lice developed significantly more slowly on the Guddal stock than on the other stocks. Salmon louse abundance and density were similar for the Rivers Fortun and Sima stocks of sea trout, and abundance of lice, though not density, was highest for farmed Atlantic salmon. Within stocks, there were no differences in infection levels of salmon louse between mature and immature fish, between sexes, or between anal-fin-clipped and non-clipped salmon. Differences in infection level among the sea trout stocks may, it is suggested, reflect genetic differences.
4
Vaz-Velho, M., G. Duarte, and P. Gibbs. "Note. Occurrence of Listeria spp. in salmon-trout (Onchorhyncus mykiss) and salmon (Salmo salar) / Nota. Presencia de Listeria spp. en trucha asalmonada (Onchorhyncus mykiss) y salmón (Salmo salar)." Food Science and Technology International 4, no. 2 (April 1998): 121–25. http://dx.doi.org/10.1177/108201329800400207.
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Salmon-trout ( Onchorhyncus mykiss) and salmon ( Salmo salar) are the main raw materials in the cold-smoked fish industry. It is important to prevent the contamination of these ready-to-eat products with Listeria monocytogenes and other ( Listeria spp.) because the temperature used in the cold-smoking process is not sufficient to inactivate these organisms. The presence of Listeria spp. and L. monocytogenes in the cold-smoked salmon and salmon-trout processing chains of three Portuguese factories examined was already confirmed in previous studies. Thus, it was important to ascertain the possible sources of contamination, the raw material being the most important one. All the Portuguese cold-smoking fish factories use fresh salmon-trout from two trout farms in the north of Portugal and Norwegian salmon which arrives by lorry every week under refrigeration, imported always by the same company; 88 samples of salmon and salmon-trout were analysed; 67 environmental samples from the two trout farms were also examined. The overall frequency ( n = 40) of Listeria spp. and L. monocytogenes in salmon was 12 and 0% respectively. The overall frequency (n = 48) of Listeria spp. and L. monocytogenes in salmon-trout was 6.3 and 2.1% respec tively. Listeria was not found in the environmental samples.
5
Gerig, Brandon S., David N. Weber, Dominic T. Chaloner, Lillian M. McGill, and Gary A. Lamberti. "Interactive effects of introduced Pacific salmon and brown trout on native brook trout: an experimental and modeling approach." Canadian Journal of Fisheries and Aquatic Sciences 75, no. 4 (April 2018): 538–48. http://dx.doi.org/10.1139/cjfas-2016-0502.
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Pacific salmon (Oncoryhnchus spp.) and brown trout (Salmo trutta) are introduced species stocked in the Laurentian Great Lakes. In their native range, salmon deliver material that enhances growth, alters isotopic ratios, and increases contaminant burdens of resident fish. However, whether salmon subsidies mediate interactions between competing species is unknown. Here, we employed a mesocosm experiment and a simulation model to determine if salmon tissue consumption influences brook trout (Salvelinus fontinalis) growth, isotopic ratios, and mercury concentrations and whether these were modified by brown trout. Our results indicate that brook trout growth did not increase with provision of salmon tissue and was not reduced by brown trout. However, brook trout exhibited isotopic enrichment and increased mercury concentrations, suggesting dietary intake of salmon tissue. Because salmon eggs have a higher energy density and lower mercury concentration compared with salmon tissue, our simulation model suggests that consumption of salmon eggs rather than tissue can increase growth while reducing mercury accumulation. Overall, our results suggest that the role of introduced Pacific salmon is dependent on both food quantity and quality along with diet contaminant concentrations.
6
Vollset, Knut Wiik, Elina Halttunen, Bengt Finstad, Ørjan Karlsen, Pål Arne Bjørn, and Ian Dohoo. "Salmon lice infestations on sea trout predicts infestations on migrating salmon post-smolts." ICES Journal of Marine Science 74, no. 9 (June 1, 2017): 2354–63. http://dx.doi.org/10.1093/icesjms/fsx090.
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Abstract Impacts of sea lice (Lepeophtheirus salmonis or Caligus spp.) on wild salmonids is currently one of the most important issues facing management of fish farms in salmon producing countries in the northern hemisphere. Surveillance of sea lice on wild Atlantic salmon (Salmo salar) is often hampered by the ability to catch enough migrating post-smolts. Therefore, sea lice abundance on anadromous trout (Salmo trutta) is often used to infer sea lice abundance on migrating salmon post-smolt. However, the assumption that there is a relationship between the abundance of lice on salmon and trout has never been tested. Here we use a dataset of sea lice on salmon post-smolt and sea trout that have been caught simultaneously in trawl hauls, to evaluate the correlation in abundance of sea lice between the two species using various statistical models. We demonstrate that trout generally has higher abundances of sea lice than salmon. Average lice per gram fish on sea trout (log transformed) predicted the abundance of lice on salmon best. Negative binomial models of lice counts were preferable to using trout lice counts as direct estimates of salmon lice abundance, and they had better predictive ability than logit models of high (vs. low) lice counts. Including the size of the salmon increased the predictive ability of the model, but these data are not generally available. The effect of salmon weight may have been a direct effect of body size, or an indirect effect of time spent in marine waters. Finally, we predict lower salmon lice counts on migrating salmon with our selected binomial model than with the current method of using trout lice counts as a direct estimator on salmon lice counts, and demonstrate that management advice would change considerably depending on the chosen method.
7
Hearn, William E., and Boyd E. Kynard. "Habitat Utilization and Behavioral Interaction of Juvenile Atlantic Salmon (Salmo salar) and Rainbow Trout (S. gairdneri) in Tributaries of the White River of Vermont." Canadian Journal of Fisheries and Aquatic Sciences 43, no. 10 (October 1, 1986): 1988–98. http://dx.doi.org/10.1139/f86-244.
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Competition for space between stocked juvenile Atlantic salmon, Salmo salar, and wild juvenile rainbow trout, S. gairdneri, was examined in stream channel experiments, a field experiment, and in field habitat surveys. In stream channels providing riffle and pool habitats, species differed in their distribution both as underyearlings (0+) and as yearlings (1+). Yearling salmon occurred more often in stream channel riffles during trials with 1+ rainbow trout than during trials testing only salmon; trout distributions in the channels were unaffected by salmon. In a field experiment conducted to determine if the stocking of 0+ Atlantic salmon causes the displacement of resident 0+ rainbow trout, salmon fry were stocked at a density of 85 per 100 m2. Emigration from the stocked zone and an unstocked control zone were then monitored daily with four weirs. The 0+ salmon had no apparent effect on the rate of movement of resident rainbow trout fry. During summer and fall field surveys, 0+ salmon occupied deeper and swifter water than 0+ rainbow trout; as yearlings these species occupied similar habitats. In late fall, segregation by habitat occurred: Atlantic salmon were primarily in riffles; rainbow trout were primarily in pools. We found no evidence of competition between cohorts of underyearlings; however, the niche shift by 1+ salmon in the stream channels suggested that, at times, juveniles of these species will compete for space.
8
Hermann, Nathan T., Dominic T. Chaloner, Brandon S. Gerig, and Gary A. Lamberti. "Ecological consequences of Great Lakes salmon subsidies for stream-resident brook and brown trout." Canadian Journal of Fisheries and Aquatic Sciences 77, no. 11 (November 2020): 1758–71. http://dx.doi.org/10.1139/cjfas-2020-0086.
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Introduced Pacific salmon (Oncorhynchus spp.) deliver novel, pulsed resource subsidies to Great Lakes streams. We explored interactions between native brook trout (Salvelinus fontinalis) and non-native brown trout (Salmo trutta) in the context of this resource pulse. Diets surveyed before and during salmon spawning showed that, regardless of species, trout consumed 4.5-fold more biomass during than before salmon runs. Brook trout grew more quickly than brown trout under controlled feeding regimes due, in part, to their higher food conversion efficiency of 36% compared with 21%. Bioenergetics model simulations explored the influence of temperature on the exploitation of resource pulses and found 35% lower growth rates and increased gorging at colder temperatures. Overall, we found evidence that brook trout and brown trout foraging and growth are modulated by the salmon resource pulse, especially through gorging on eggs. However, these species exhibit distinct physiological adaptations and environmental preferences that may influence their ultimate capacity to exploit resource pulses. The effects of environmental conditions and salmon subsidies on stream-resident trout have broader consequences for fisheries management and conservation efforts.
9
Abuín, M., P. Martínez, L. Sánchez, C. Clabby, F. Flavin, N. P. Wilkins, J. A. Houghton, R. Powell, and U. Goswami. "A NOR-associated repetitive element present in the genome of two Salmo species (salmo salar and Salmo trutta)." Genome 39, no. 4 (August 1, 1996): 671–79. http://dx.doi.org/10.1139/g96-085.
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A repetitive element was isolated from the genome of Atlantic salmon. Nucleotide sequence analysis revealed the existence of variant monomers that range in length from approximately 200 to 230 bp. Repeat monomers contain regions of cryptic simplicity, internal repetition, and long direct repeats with deletions and insertions between individual units. The repetitive element was shown to have a tandem unit arrangement and was estimated to occupy between two and three percent of the Atlantic salmon genome. Southern blot analysis revealed the repetitive element to be unique to Atlantic salmon and brown trout species. In situ hybridization analysis showed this element to be localized at the main nucleolar organizer region bearing chromosomes of Atlantic salmon (Salmo salar), AS cell line (derived from S. salar), and brown trout (Salmo trutta). Key words : Atlantic salmon, brown trout, AS cell line, repeat DNA, NOR.
10
Salán, Eduardo Oliveira, Juliana Antunes Galvão, and Marília Oetterer. "Use of smoking to add value to the salmoned trout." Brazilian Archives of Biology and Technology 49, no. 1 (January 2006): 57–62. http://dx.doi.org/10.1590/s1516-89132006000100007.
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The objective of this study was to make a comparison between the characteristics of salmoned trout (Salmo truta) and salmon (Salmo salar) in terms of coloration (CIE L*a*b*), proximate composition, pH and sensory attributes of fresh and smoked fillets in order to obtain a possible alternative for the substitution of imported salmon for Brazilian salmoned trout as a commercial equivalent for retail sales. Results showed that no statistical difference was found for most of the sensory attributes analyzed and for pH. Although the coloration of the fillets presented a statistical difference, the trout presented a more intense coloration than the salmon, proving to be, therefore, convenient to agroindustry.
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CARRERA, ESTHER, TERESA GARCÍA, ANA CÉSPEDES, ISABEL GONZÁLEZ, BERNABÉ SANZ, PABLO E. HERNÁNDEZ, and ROSARIO MARTÍN. "Identification of Atlantic Salmon (Salmo salar) and Rainbow Trout (Oncorhynchus mykiss) by Using Polymerase Chain Reaction Amplification and Restriction Analysis of the Mitochondrial Cytochrome b Gene." Journal of Food Protection 61, no. 4 (April 1, 1998): 482–86. http://dx.doi.org/10.4315/0362-028x-61.4.482.
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Restriction site analysis of polymerase chain reaction (PCR) products from a conserved region of the cytochrome b gene has been used for the identification of fresh and smoked samples of Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss). Digestion of the 359-bp PCR product with the endonucleases EcoRV and TaqI yielded specific banding patterns for salmon and trout. This genetic marker can be very useful for detecting fraudulent substitution of the cheaper smoked trout for the more expensive smoked salmon.
12
Youngson, A. F., J. H. Webb, C. E. Thompson, and D. Knox. "Spawning of Escaped Farmed Atlantic Salmon (Salmo salar): Hybridization of Females with Brown Trout (Salmo trutta)." Canadian Journal of Fisheries and Aquatic Sciences 50, no. 9 (September 1, 1993): 1986–90. http://dx.doi.org/10.1139/f93-221.
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Atlantic salmon (Salmo salar) and F1 hybrids between Atlantic salmon and brown trout (Salmo trutta) were distinguished among juvenile salmonids sampled at emergence from rivers in western and northern Scotland. Hybrids were present in samples obtained from seven of the 16 rivers examined. Salmon fry and hybrid fry that were demonstrably the progeny of female salmon that had escaped from fish farms were identified by detecting the presence of maternal canthaxanthin, a synthetic flesh colorant, in the juveniles' pigment load. Canthaxanthin was detected in 101 (4%) of the 2350 salmon and eight (35%) of the 23 hybrids examined. The difference in the frequencies of salmon and hybrids carrying canthaxanthin was significant. Escaped female salmon hybridized with trout more frequently than did wild females.
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Dahl, Jonas, Johan Dannewitz, Lars Karlsson, Erik Petersson, Anna Löf, and Bjarne Ragnarsson. "The timing of spawning migration: implications of environmental variation, life history, and sex." Canadian Journal of Zoology 82, no. 12 (December 1, 2004): 1864–70. http://dx.doi.org/10.1139/z04-184.
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During 1960–2002, the arrival times of all spawning male and female Atlantic salmon (Salmo salar L., 1758) and brown trout (Salmo trutta L., 1758) entering Dalälven River were recorded. To study the role of environmental variation in spawning migration timing, we used long-term temperature (river and sea) and river discharge data. For salmon, the spawning migration peak was strongly correlated with mean monthly sea and river temperatures during spring: salmon arrived earlier when temperatures were higher and later when temperatures were lower. River discharge explained little of the variation in migration timing. Female salmon migration showed a stronger correlation with temperature than male salmon migration, and female salmon arrived ≈18 days earlier than males. Trout showed a larger variation in their spawning migration, but river and sea temperatures and river discharge explained little of the variation. Trout females arrived ≈7 days earlier than males. The sea and river temperatures were highly correlated during the spawning migration, indicating that large climate processes determine the temperature regimes in the Baltic Sea and its tributaries. Time of arrival at the river was not correlated with ovulation date; a female salmon or brown trout arriving late could ovulate almost immediately, whereas a female arriving early could wait to ovulate.
14
Muzzall, Patrick M. "Endohelminths of salmonids from two localities in eastern Lake Michigan, with emphasis on Echinorhynchus salmonis." Canadian Journal of Zoology 67, no. 6 (June 1, 1989): 1604–7. http://dx.doi.org/10.1139/z89-227.
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Adult salmonids (101 chinook salmon, Oncorhynchus tshawytscha; 7 coho salmon, Oncorhynchus kisutch; 56 lake trout, Salvelinus namaycush; 6 steelhead, Salmo gairdneri; and 2 brown trout, Salmo trutta) were collected from eastern Lake Michigan (Ludington and Manistee, Michigan) in July–September 1986, and examined for helminths. Eight species (three Cestoda, three Nematoda, two Acanthocephala) were found in the digestive tract and other viscera. Echinorhynchus salmonis and Eubothrium salvelini were the most common helminths found. The intensity of E. salmonis significantly increased as chinook salmon became older and longer.
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Tucker, S., and J. B. Rasmussen. "Using 137Cs to measure and compare bioenergetic budgets of juvenile Atlantic salmon (Salmo salar) and brook trout (Salvelinus fontinalis) in the field." Canadian Journal of Fisheries and Aquatic Sciences 56, no. 5 (May 1, 1999): 875–87. http://dx.doi.org/10.1139/f99-025.
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Through the 137Cs mass balance method, annual consumption rates were estimated for juvenile Atlantic salmon (Salmo salar) parr and precocious males as well as for brook trout (Salvelinus fontinalis) at four sites in the Ste-Marguerite River system, Québec. With explicit age analysis, consumption rates and growth rates were derived on an individual fish and age-class basis. These represent the first consumption estimates for Atlantic salmon in the wild. Precocious males had consumption rates 1.5 times greater than nonmaturing parr, while Atlantic salmon parr consumption rates were 2.7 times greater than brook trout. There was a strong positive relationship between individual annual consumption and growth rates for Atlantic salmon and brook trout at all sites. Subsequently the concept of field maintenance ration was introduced as the intercept of consumption over growth. Maintenance rations for Atlantic salmon parr ranged from 0.010 to 0.016 g·g-1·day-1 between sites. Brook trout had maintenance rations approximately half those of Atlantic salmon at 0.0059 g·g-1·day-1. Precocious male growth efficiencies were half those of nonmaturing parr despite higher feeding and growth rates. Brook trout growth efficiencies were significantly greater than those of Atlantic salmon parr. The lower growth efficiencies observed for Atlantic salmon are likely due to increased metabolic costs associated with higher activity. On average, Atlantic salmon parr spent 2.4-fold more energy in activity than brook trout. Atlantic salmon precocious males spent 1.7 times more energy in activity than parr.
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Kornis, Matthew S., David B. Bunnell, Heidi K. Swanson, and Charles R. Bronte. "Spatiotemporal patterns in trophic niche overlap among five salmonines in Lake Michigan, USA." Canadian Journal of Fisheries and Aquatic Sciences 77, no. 6 (June 2020): 1059–75. http://dx.doi.org/10.1139/cjfas-2019-0288.
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Native lake trout (Salvelinus namaycush) and introduced Chinook salmon (Oncorhynchus tshawytscha), coho salmon (Oncorhynchus kisutch), steelhead (Oncorhynchus mykiss), and brown trout (Salmo trutta) are major predators in Lake Michigan’s complex ecosystem and collectively support a valuable recreational fishery, but declines in their primary prey, alewife (Alosa pseudoharengus), have raised ecological and management concerns about competition and prey allocation. We applied niche overlap analysis to evaluate competition among salmonine predators during rapid forage base change in Lake Michigan. δ13C and δ15N stable isotope ratios indicated that lake trout had a unique trophic niche from inclusion of offshore and benthic prey, with <29% lake-wide niche overlap with Chinook salmon, coho salmon, and steelhead. Brown trout had moderate overlap with other species (45%–91%), while Chinook salmon, coho salmon, and steelhead had high overlap (71%–98%). Regional differences in isotopic signatures highlighted the potential importance of subsystem differences in fish diets in large aquatic systems. The uniqueness of the lake trout niche, and broadness of brown trout and steelhead niches, suggest these species may be resilient to forage base changes. This study further demonstrates how niche overlap analysis can be applied to tease apart competitive interactions and their response to ecosystem change.
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Devlin, Robert H. "Sequence of Sockeye Salmon Type 1 and 2 Growth Hormone Genes and the Relationship of Rainbow Trout with Atlantic and Pacific Salmon." Canadian Journal of Fisheries and Aquatic Sciences 50, no. 8 (August 1, 1993): 1738–48. http://dx.doi.org/10.1139/f93-195.
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Two types of growth hormone genes have been isolated from sockeye salmon (Oncorhynchus nerka) and their complete nucleotide sequence determined. The genes encode proteins of 210 amino acids and show considerable similarity to growth hormones characterized in other salmonids and fishes. The two genes presumably arose from a gene duplication event that generated the tetraploid condition in salmonids and are highly conserved in their coding regions. The sequences have diverged approximately 18% in noncoding regions since the gene duplication event and show numerous deletions and/or insertions. Isolation of these two genes from a Pacific salmon allows comparison of their sequences to growth hormone genes characterized from rainbow trout and from Atlantic salmon. The results indicate that rainbow trout is more similar to Pacific than to Atlantic salmon and suggest that Atlantic salmon diverged from Pacific salmonids at a time when sockeye and rainbow trout were part of a common breeding population. These results support the recent reclassification of rainbow trout from the genus Salmo to Oncorhynchus.
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Bjørn, P. A., B. Finstad, R. Kristoffersen, R. S. McKinley, and A. H. Rikardsen. "Differences in risks and consequences of salmon louse, Lepeophtheirus salmonis (Krøyer), infestation on sympatric populations of Atlantic salmon, brown trout, and Arctic charr within northern fjords." ICES Journal of Marine Science 64, no. 2 (December 18, 2006): 386–93. http://dx.doi.org/10.1093/icesjms/fsl029.
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Abstract Bjørn, P-A., Finstad, B., Kristoffersen, R., Rikardsen, A. H., and McKinley, R. S. 2007. Differences in risks and consequences of salmon louse, Lepeophtheirus salmonis (Krøyer), infestation on sympatric populations of Atlantic salmon, brown trout, and Arctic charr within northern fjords. – ICES Journal of Marine Science, 64: 386–393. Differences in salmon louse (Lepeophtheirus salmonis) infestation on sympatric populations of fjord-migrating, Atlantic salmon post-smolts (Salmo salar), brown trout (Salmo trutta) (sea trout), and Arctic charr (Salvelinus alpinus) were studied in three fjords with fish-farming activity in northern Norway during the period June–August 2000. Atlantic salmon post-smolts were only captured in the fjords during late June and early July, and probably left them subsequently. No fish were infested with salmon lice. In contrast, brown trout and Arctic charr had similar infection patterns during their sampling periods, with very low prevalence and mean infection intensity during June (0–21% and 0–6 lice per fish, respectively), slightly increasing in July (8–70% and 6–12 lice per fish, respectively), and peaking in August (80–88% and 19–27 lice per fish, respectively). The chalimus stages dominated during June and July, with a few pre-adult and adult stages observed in July, and all stages were found frequently during August. The observations indicate that Atlantic salmon may have a mismatch between the time of louse infestation and their post-smolt fjord migration in northern fjords. In contrast, brown trout and Arctic charr feed within the fjords throughout summer and have a higher risk of harmful infestation in years with suitable environmental conditions for salmon louse development, especially in fish‐farming areas. Arctic charr usually spend the shortest time at sea of the three species, and the salmon lice may not have time to develop to the adult stage on this species.
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Gargan, P. G., G. Forde, N. Hazon, D. J. F. Russell, and C. D. Todd. "Evidence for sea lice-induced marine mortality of Atlantic salmon (Salmo salar) in western Ireland from experimental releases of ranched smolts treated with emamectin benzoate." Canadian Journal of Fisheries and Aquatic Sciences 69, no. 2 (February 2012): 343–53. http://dx.doi.org/10.1139/f2011-155.
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Sea trout ( Salmo trutta ) stock collapses in coastal areas of western Ireland subject to salmon aquaculture were contemporaneous with high abundances of larval sea lice ( Lepeophtheirus salmonis ) on juvenile sea trout. Whereas sea trout remain in near-shore waters throughout their marine migration, Atlantic salmon ( Salmo salar ) smolts typically move quickly offshore into oceanic waters. It might therefore be predicted that salmon smolts would be less vulnerable to coastal stressors and less likely to be negatively affected by infestations of sea lice early in their marine phase. Groups of microtagged, hatchery-reared Atlantic salmon smolts were fed either untreated pellets or pellets incorporating the in-feed sea louse treatment SLICE (emamectin benzoate) prior to eight experimental releases in three marine locations over a 3-year period. In total, 74 324 smolts were released and analysis of tag recaptures from returning adult salmon showed that emamectin-treated smolts experienced increased survivorship and were 1.8 times more likely to return compared with control fish. These results suggest that sea lice-induced mortality on adult Atlantic salmon returns in Ireland can be significant, and that sea lice larvae emanating from farmed salmon may influence individual survivorship and population conservation status of wild salmon in these river systems.
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Goodier, John L., and William S. Davidson. "Characterization of a repetitive element detected by NheI in the genomes of Salmo species." Genome 37, no. 4 (August 1, 1994): 639–45. http://dx.doi.org/10.1139/g94-091.
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The genomes of the two species in the genus Salmo (Atlantic salmon, S. salar; brown trout, S. trutta) contain a 380-bp repetitive element that is flanked by the recognition sequence of the restriction enzyme NheI. These elements, which comprise approximately 1.2% of the salmon genome, do not exist in long tandem arrays as is typical of satellite DNA. A comparison of the sequences of 16 salmon and 7 trout elements revealed that members of this family of repetitive DNA are closely related to one another (over 95% identity). Subfamily structure exists and there is evidence that members of the same subfamilies are found in both Salmo species. A search of the GenBank database indicated that sequences homologous to the NheI repeat are located within a 1424-bp segment inserted immediately downstream of the 5′ end of a Tc1 transposon-like sequence isolated from Atlantic salmon (A.R. Radice, B. Bugaj, D.H. Fitch, and S.W. Emmons, unpublished data; GenBank accession No. L12206).Key words: satellite DNA, Atlantic salmon, brown trout, Tc1-like transposon, evolution.
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Harwood, A. J., N. B. Metcalfe, J. D. Armstrong, and S. W. Griffiths. "Spatial and temporal effects of interspecific competition between Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) in winter." Canadian Journal of Fisheries and Aquatic Sciences 58, no. 6 (June 1, 2001): 1133–40. http://dx.doi.org/10.1139/f01-061.
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Previous work has shown that juvenile stream-dwelling salmonids become predominantly nocturnal during winter by emerging from daytime refuges to feed, with several species having been shown to prefer slow-flowing water while active at night. We used seminatural stream channels, landscaped to provide a choice of water depths, and hence velocities, to test whether Atlantic salmon, Salmo salar, and brown trout, Salmo trutta, show similar habitat preferences during winter. We also tested whether there was any spatial or temporal displacement of Atlantic salmon when in sympatry with brown trout. Nighttime observations revealed that Atlantic salmon did have a preference for slow-flowing water. However, when in direct competition with trout, salmon either remained predominantly nocturnal but occupied shallower water, or became significantly less nocturnal, spending more time active during the day than when in allopatry. These results, which were especially marked in relatively larger fish, indicate that competition between the two species for food and resources is not restricted to the summer months and may affect both the short- and long-term growth and survival of overwintering wild Atlantic salmon.
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Keefe, MaryLouise. "Chemically mediated avoidance behavior in wild brook trout, Salvelinus fontinalis: the response to familiar and unfamiliar predaceous fishes and the influence of fish diet." Canadian Journal of Zoology 70, no. 2 (February 1, 1992): 288–92. http://dx.doi.org/10.1139/z92-043.
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Choice experiments were used to determine whether juvenile wild brook trout would avoid chemical traces of predaceous fishes found in their native stream; the fishes used were the red fin pickerel (Esox americanus) and American eel (Anguilla rostrata), and a predaceous fish with which the trout had no prior experience, the Atlantic salmon (Salmo salar). Juvenile trout avoided pickerel odors but did not avoid water conditioned by American eels. They also avoided water conditioned with Atlantic salmon. A second experiment using trout from two wild populations demonstrated that the brook trout's avoidance of Atlantic salmon was a response to the salmon's piscivorous diet. These results suggest that brook trout do not avoid odors of all predaceous fishes and are capable of altering their behavior patterns in response to a change in the diet of a predatory fish.
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Raffenberg, Matthew J., and Donna L. Parrish. "Interactions of Atlantic salmon (Salmo salar) and trout (Salvelinus fontinalis and Oncorhynchus mykiss) in Vermont tributaries of the Connecticut River." Canadian Journal of Fisheries and Aquatic Sciences 60, no. 3 (March 1, 2003): 279–85. http://dx.doi.org/10.1139/f03-021.
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Competitive interactions among stream salmonids in resource-limited environments have been linked to reduced success for many species. Few studies have focused on interactions at scales larger than individual fish or stream reach. We chose to focus our study on these larger scales to provide information for managing species that have complex life histories transcending multiple scales. Our objective was to explore age-0 Atlantic salmon (Salmo salar) growth and survival in relation to trout abundance (introduced rainbow (Oncorhynchus mykiss) and native brook (Salvelinus fontinalis) trout) and prey resources at 24 stream reaches across two Vermont watersheds that flow into the Connecticut River. Simple linear and multilinear regressions were conducted on response and predictor variables related to fish and invertebrate prey. Age-0 Atlantic salmon survival was greatest at the site with highest trout abundance; however, no linear relationships to trout abundance were detected possibly because Atlantic salmon growth and survival were highly variable across sites. In contrast, a positive significant multivariate relationship was identified among age-0 Atlantic salmon survival, the abundance of age-1+ brook trout (i.e., 100130 mm), and benthic prey abundance. These results suggest that stocking streams based on trout abundance may not increase Atlantic salmon growth and survival during the first summer of life.
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Hedger, RD, OH Diserud, B. Finstad, AJ Jensen, DK Hendrichsen, O. Ugedal, and TF Næsje. "Modeling salmon lice effects on sea trout population dynamics using an individual-based approach." Aquaculture Environment Interactions 13 (May 6, 2021): 145–63. http://dx.doi.org/10.3354/aei00397.
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Salmon lice Lepeophtheirus salmonis infestation of sea trout Salmo trutta results in both additional marine mortality and behavioral changes which may contribute to sea trout population decline. For effective management of activities that increase exposure to salmon lice, such as salmon aquaculture, it is necessary to have a full understanding of how salmon lice may affect sea trout populations. An individual-based model (IBTRUTTA) was therefore developed to investigate the potential effects of salmon lice infestation on sea trout population abundance and dynamics based on data from the River Halselva and Altafjord system in northern Norway. This model allowed investigation of the effect of lice-induced mortality and also the compensatory salmonid behavioral mechanisms of premature return to freshwater, either persistent for overwintering or transitory after which sea trout could go back to sea. It was found that, in the absence of compensatory mechanisms, even low rates of lice infestation could lead to marked declines in sea trout abundance. Compensatory behavioral mechanisms had the potential to reduce these declines, but persistent premature return resulted in reduced body mass of returning adults. The shape of the stock-recruitment relationship was also shown to strongly affect how lice-induced mortality impacted the population.
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Ormsby, Michael J., Thomas Caws, Richard Burchmore, Tim Wallis, David W. Verner-Jeffreys, and Robert L. Davies. "Yersinia ruckeri Isolates Recovered from Diseased Atlantic Salmon (Salmo salar) in Scotland Are More Diverse than Those from Rainbow Trout (Oncorhynchus mykiss) and Represent Distinct Subpopulations." Applied and Environmental Microbiology 82, no. 19 (July 22, 2016): 5785–94. http://dx.doi.org/10.1128/aem.01173-16.
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ABSTRACTYersinia ruckeriis the etiological agent of enteric redmouth (ERM) disease of farmed salmonids. Enteric redmouth disease is traditionally associated with rainbow trout (Oncorhynchus mykiss, Walbaum), but its incidence in Atlantic salmon (Salmo salar) is increasing.Yersinia ruckeriisolates recovered from diseased Atlantic salmon have been poorly characterized, and very little is known about the relationship of the isolates associated with these two species. Phenotypic approaches were used to characterize 109Y. ruckeriisolates recovered over a 14-year period from infected Atlantic salmon in Scotland; 26 isolates from infected rainbow trout were also characterized. Biotyping, serotyping, and comparison of outer membrane protein profiles identified 19Y. ruckericlones associated with Atlantic salmon but only five associated with rainbow trout; none of the Atlantic salmon clones occurred in rainbow trout andvice versa. These findings suggest that distinct subpopulations ofY. ruckeriare associated with each species. A new O serotype (designated O8) was identified in 56 biotype 1 Atlantic salmon isolates and was the most common serotype identified from 2006 to 2011 and in 2014, suggesting an increased prevalence during the time period sampled. Rainbow trout isolates were represented almost exclusively by the same biotype 2, serotype O1 clone that has been responsible for the majority of ERM outbreaks in this species within the United Kingdom since the 1980s. However, the identification of two biotype 2, serotype O8 isolates in rainbow trout suggests that vaccines containing serotypes O1 and O8 should be evaluated in both rainbow trout and Atlantic salmon for application in Scotland.IMPORTANCEVaccination plays an important role in protecting Atlantic salmon against the bacterial pathogenYersinia ruckeri, but, in recent years, there has been an increasing incidence of vaccine breakdown in salmon. This is largely because current vaccines are aimed at rainbow trout and are based on serotypes specific for this species. A wider range of serotypes is responsible for infection in Atlantic salmon, but very little is known about the diversity of these strains and their relationships to those recovered from rainbow trout. In the present study, we demonstrate thatY. ruckeriisolates recovered from diseased Atlantic salmon in Scotland are more diverse than those from rainbow trout; furthermore, isolates from the two species represent distinct subpopulations. In addition, a new O serotype was identified that is responsible for a significant proportion of the disease in Atlantic salmon. Our findings are likely to have important implications for the development of improved vaccines againstY. ruckeri.
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Coughlan, James, Philip McGinnity, Brian O'Farrell, Eileen Dillane, Ola Diserud, Elvira de Eyto, Killian Farrell, Ken Whelan, René J. M. Stet, and Thomas F. Cross. "Temporal variation in an immune response gene (MHC I) in anadromous Salmo trutta in an Irish river before and during aquaculture activities." ICES Journal of Marine Science 63, no. 7 (January 1, 2006): 1248–55. http://dx.doi.org/10.1016/j.icesjms.2006.03.025.
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Abstract Several studies have documented the genetic effects of intraspecific hybridization of cultured and wild Atlantic salmon (Salmo salar L.). However, the effect of salmon aquaculture on wild congeners is not so well understood. Diseases, introduced or increased in incidence by salmon aquaculture activities, may have an impact on co-occurring wild sea trout (Salmo trutta L.), as implied by the steep decline in sea trout numbers in many Irish, Scottish, and Norwegian rivers since the late 1980s, which may be linked to sea lice infestations associated with marine salmonid farming. Our data suggest that salmon farming and ocean ranching can indirectly affect, most likely mediated by disease, the genetics of cohabiting sea trout by reducing variability at major histocompatibility class I genes. We studied samples of DNA extracted from scales of sea trout in the Burrishoole River, in the west of Ireland, before and at intervals during aquaculture activities. In these samples, allelic variation at a microsatellite marker, tightly linked to a locus critical to immune response (Satr-UBA), was compared with variation at six neutral microsatellite loci. A significant decline in allelic richness and gene diversity at the Satr-UBA marker locus, observed since aquaculture started and which may indicate a selective response, was not reflected by similar reductions at neutral loci. Subsequent recovery of variability at the Satr-UBA marker, seen among later samples, may reflect an increased contribution by resident brown trout to the remaining sea trout stock.
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Brown, Grant E., and Joseph A. Brown. "Do rainbow trout and Atlantic salmon discriminate kin?" Canadian Journal of Zoology 70, no. 8 (August 1, 1992): 1636–40. http://dx.doi.org/10.1139/z92-227.
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The purpose of this study was to determine if juvenile Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss) can discriminate kin from non-kin, since other salmonid species (coho salmon (Oncorhynchus kisutch) and Arctic charr (Salvelinus alpinus)) have been shown to possess this ability. When tested in water conditioned by conspecifics (kin and non-kin) and heterospecifics in a two-choice tank, both rainbow trout and Atlantic salmon demonstrated a significant preference for kin over non-kin and heterospecifics, indicating that these species possess kin-discrimination abilities. This ability appears to be widespread among salmonid fishes.
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Maraldo, Dave, Brad Bowman, and Mike Gillies. "The Return of Atlantic Salmon Salmo salar to Trout Lake, North Bay, Ontario." Water Quality Research Journal 32, no. 2 (May 1, 1997): 347–64. http://dx.doi.org/10.2166/wqrj.1997.023.
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Abstract In 1935, landlocked Atlantic salmon or ouananiche Salmo salar were introduced into Trout Lake, a 1,674-ha oligotrophic lake. The salmon reproduced in Four Mile Creek and became the only naturally reproducing population in Ontario. Anglers reported good catches of salmon in the 1950s and 60s, with fish up to 6 kg taken. In 1967, a train derailment resulted in the spillage of an unspecified volume of zinc concentrate into the Four Mile Creek watershed. Water quality monitoring completed in 1979 documented zinc levels in Four Mile Creek downstream of the derailment area ranging from 130 to 340 µg/L. In retrospect, it was believed that this elevated level of zinc resulted in adult salmon avoiding Four Mile Creek. Since this was the only stream suitable for spawning, reproduction ceased and salmon disappeared. The last known catch of Atlantic salmon in Trout Lake occurred in the early 1970s. In 1980, approximately 250,000 tonnes of zinc-contaminated soil was excavated from the area. In situ toxicity studies in 1981 produced 20% mortality of rainbow trout Oncorhynchus mykiss yearlings during a 48-hour exposure period downstream of the derailment area. In-stream zinc concentrations ranged from 110 to 160 µg/L during the exposure period. Rainbow trout stocked into Four Mile Creek from 1983-88 survived. Atlantic salmon were first reintroduced in 1989 as fall fingerlings. Adult salmon appeared in the creek in November 1992, and again in 1994 and 1995. Electrofishing studies confirmed the presence of naturally reproduced juvenile salmon in 1994 and 1995. As yet the population of adult salmon in Trout Lake is low but may increase as naturally reproduced salmon smolt and enter the lake. Zinc concentrations in Four Mile Creek have continued to decline as a function of time. In 1994, they ranged from 7 to 48 µg/L.
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CARRERA, ESTHER, ROSARIO MARTÍN, TERESA GARCÍA, ISABEL GONZÁLEZ, BERNABE SANZ, and PABLO E. HERNÁNDEZ. "Development of an Enzyme-Linked Immunosorbent Assay for the Identification of Smoked Salmon (Salmo salar),Trout (Oncorhynchus mykiss) and Bream (Brama raii)." Journal of Food Protection 59, no. 5 (May 1, 1996): 521–24. http://dx.doi.org/10.4315/0362-028x-59.5.521.
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An indirect enzyme-linked immunosorbent assay (ELISA) has been developed for the identification of smoked meat from salmon (Salmo salar), trout (Oncorhynchus mykiss), and bream (Erama raii). The assay uses polyclonal antibodies raised in rabbits against soluble proteins of muscle from salmon (anti-SSP), trout (anti-TSP), and bream (anti-BSP) which are rendered species-specific by blocking them with the heterologous soluble muscle proteins. The blocked antibodies were used to detect the samples from smoked fish bound to the wells of a microtiter plate. Immunorecognition of polyclonal antibodies adsorbed to fish samples was made with goat anti-rabbit immunoglobulins conjugated to the enzyme horseradish peroxidase. Subsequent enzymic coversion of the substrate allowed clear species identification of smoked meat of salmon, trout, and bream.
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Apriliani, Tenny, and Rismutia Hayu Deswati. "STRATEGI PENGENDALIAN IMPOR SALMON-TROUT UNTUK KONSUMSI PASAR DALAM NEGERI." Jurnal Kebijakan Sosial Ekonomi Kelautan dan Perikanan 10, no. 2 (December 29, 2020): 141. http://dx.doi.org/10.15578/jksekp.v10i2.9297.
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Impor ikan salmon-trout semakin meningkat seiring bervariasinya menu masakan Jepang di Indonesia pada sejumlah hotel, restoran dan katering. Pengendalian impor terhadap komoditas harus dilakukan sebagai upaya mengurangi defisit neraca perdagangan. Pengendalian impor ikan salmon-trout sangat penting dilakukan karena merupakan produk pesaing ikan lokal dan berpotensi menurunkan permintaan terhadap ikan lokal. Oleh karena itu, penelitian ini bertujuan merumuskan strategi pengendalian impor ikan salmon-trout terutama untuk konsumsi hotel, restoran, katering, pasar modern (Horekapasmod) dan industri pengolahan ikan (re-ekspor). Data primer dan sekunder digunakan dalam penelitian ini. Data primer berasal dari wawancara dan diskusi dengan pemangku kepentingan impor salmon-trout pada bulan bulan Maret hingga September 2019 di DKI Jakarta dan Jawa Timur sebagai pintu masuk impor utama ikan salmon-trout. Data sekunder juga dikumpulkan dari berbagai institusi seperti BPS dan berbagai hasil penelitian beberapa perguruan tinggi. Data yang dikumpulkan kemudian dianalisis dengan menggunakan metode analysis hierarchy process (AHP) untuk merumuskan strategi pengendalian impor salmon-trout. Strategi pengendalian impor salmon-trout berdasarkan hasil analisis disusun berdasarkan prioritas. Prioritas pertama dengan bobot nilai 0,413 adalah sosialisasi dan edukasi kepada masyarakat tentang jenis ikan yang memiliki kandungan gizi sama dengan salmon-trout. Prioritas kedua adalah peningkatan ketersediaan dan perbaikan kualitas ikan lokal yang potensial mensubstitusi salmon-trout dengan bobot 0.363. Prioritas ketiga adalah mengikuti kerjasama perdagangan internasional untuk ekspansi pasar ekspor khususnya untuk fillet salmon-trout dengan bobot sebesar 0,224. Pelaksanaan strategi tersebut diharapkan dapat meningkatkan konsumsi ikan lokal yang asupan gizinya tidak kalah dengan salmon-trout sehingga alokasi impor dalam negeri dapat dikurangi secara bertahap.Title: Salmon-Trout Import Control Strategies for Domestic Market ConsumptionSalmon-trout imports has increased along with the growth of hotels, restaurants and restaurants with Japanese cuisine in Indonesia. Control of imports of commodities must be done as an effort to reduce the trade balance deficit. Import control of salmon-trout is very important because it is a local fish competitor and has the potential to reduce demand for local fish. Therefore, this study aims to formulate a salmon-trout import control strategy especially for hotels, restaurants, catering, retails and processing industry (re-export) consumption. Primary and secondary data were used in this study, primary data derived from interviews and discussions with salmon-trout importer stakeholders in March to September 2019 in DKI Jakarta and East Java as the main entry point for salmon-trout import. Secondary data was also collected and from various institutions such as BPS and various research results from several universities. The data collected then analyzed using the hierarchical process analysis (AHP) method to formulate salmon-trout import control strategies. Salmon-trout import control strategies based on the results of the analysis are arranged according to priority. The first priority with a weight value of 0.413 is socialization and education to the public about the types of fish that have the same nutritional content as Salmon-Trout. The second priority is increasing availability and improving the quality of local fish which has the potential to substitute Salmon-Trout with a weight of 0.363. The third priority is to participate in international trade cooperation for the expansion of export markets specifically for salmon-trout fillets with a weight of 0.224. The implementation of this strategy is expected to increase the consumption of local fish which are nutritionally inferior to salmon-trout so that the allocation of imports is gradually reduced.
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Jensen, Arne J., Bengt Finstad, Peder Fiske, Nils Arne Hvidsten, Audun H. Rikardsen, and Laila Saksgård. "Timing of smolt migration in sympatric populations of Atlantic salmon (Salmo salar), brown trout (Salmo trutta), and Arctic char (Salvelinus alpinus)." Canadian Journal of Fisheries and Aquatic Sciences 69, no. 4 (April 2012): 711–23. http://dx.doi.org/10.1139/f2012-005.
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A study over a 22-year period of first-time migrants (smolts) of three sympatric salmonids (Atlantic salmon ( Salmo salar ), brown trout ( Salmo trutta ), and Arctic char ( Salvelinus alpinus )) in a watercourse in northern Norway demonstrated that although there was considerable overlap in smolt migration timing among the species, Atlantic salmon migrated first, followed by Arctic char, and finally brown trout. The migration period of Arctic char had a smaller range and less annual variation than those of the two other species, possibly partly related to their more lake-dwelling habitat preference. For all species, water flow was important in explaining day-to-day variations in smolt runs. Water flow was most important for brown trout, change in flow for Atlantic salmon, whereas photoperiod was most important for Arctic char. These results suggest that both age and size of smolts and the timing of the smolt migration have been shaped by the different habitat preferences of these species both in fresh water and sea through local selection.
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Henderson, J. Nathan, and Benjamin H. Letcher. "Predation on stocked Atlantic salmon (Salmo salar) fry." Canadian Journal of Fisheries and Aquatic Sciences 60, no. 1 (January 1, 2003): 32–42. http://dx.doi.org/10.1139/f03-001.
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We studied predatorprey interactions between juvenile Atlantic salmon (Salmo salar) and trout in three Massachusetts, U.S.A., streams and in artificial streams. We sampled stomach contents of age-1+ and older salmon and trout (Salvelinus fontinalis, Salmo trutta) following salmon fry stocking in the spring of 1997 and 1998. Between 4.3 and 48.6% of the stocked fry were consumed within the first 2 days after stocking, and total fry mortality from predation varied from 4.3 to 60.7%. No significant differences were found between stomach weights of predators ( without fry weight) that consumed fry and those that did not. Artificial stream experiments testing effects of habitat complexity and predator species on predator consumption rates revealed that consumption rates were not different between brook (S. fontinalis) and brown (S. trutta) trout (p = 0.59). Predation rate tended to decrease as the percentage of riffle habitat increased but the decrease was not significant (p = 0.22). Our results indicate that predation on stocked Atlantic salmon fry can be substantial (up to 60%), appears to be short lived (2 days), and is not related in a simple way to abiotic and biotic factors.
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Armstrong, J. D. "Trout And Salmon." Journal of Fish Biology 62, no. 4 (April 2003): 984–85. http://dx.doi.org/10.1046/j.1095-8649.2003.00081.x.
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Choi, Charles. "Trout from Salmon." Scientific American 291, no. 4 (October 2004): 41. http://dx.doi.org/10.1038/scientificamerican1004-41c.
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Morin, Roderick. "Atlantic salmon (Salmo salar) in the lower Nastapoka River, Quebec: distribution and origins of salmon in eastern Hudson Bay." Canadian Journal of Zoology 69, no. 6 (June 1, 1991): 1674–81. http://dx.doi.org/10.1139/z91-232.
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Atlantic salmon have been occasionally reported along eastern Hudson Bay, north of Richmond Gulf; however, in the Nastapoka River estuary they dominated gill-net catches over a 3-year period. The results of surveys of native fishermen suggest that this is the only anadromous stock in eastern Hudson Bay. Salmon are also present in the Nastapoka River above a 35-m coastal escarpment. It is proposed that they colonized the river from Ungava Bay by headwater exchange with the Koksoak River following deglaciation. Atlantic salmon and brook trout accounted for >80% of gill-net catches in the lower Nastapoka River and estuary. Salmon and trout were similar in size up to age 7. Trout growth was linear whereas salmon growth slowed, resulting in a smaller maximum size, but longevity was greater in salmon than in trout. Salmon matured at a greater age and had lower fecundity and reproductive potential than trout. In the estuary, both species consumed mainly littoral marine amphipods and marine fishes. The salmon population is located at the northern limit of the thermal optimum reported for the species. Habitat in the lower Nastapoka River may favour salmon over trout because of the rapid current in the restricted freshwater zone below the coastal waterfall. This habitat is threatened by the proposed diversion of headwaters for hydroelectric development.
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Roloson, Scott D., Kyle M. Knysh, Michael R. S. Coffin, Karen L. Gormley, Christina C. Pater, and Michael R. van den Heuvel. "Rainbow trout (Oncorhynchus mykiss) habitat overlap with wild Atlantic salmon (Salmo salar) and brook trout (Salvelinus fontinalis) in natural streams: do habitat and landscape factors override competitive interactions?" Canadian Journal of Fisheries and Aquatic Sciences 75, no. 11 (November 2018): 1949–59. http://dx.doi.org/10.1139/cjfas-2017-0342.
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The purpose of this study was to update rainbow trout (Oncorhynchus mykiss) invasion status, delineate factors that increase the invasion probability, and quantify habitat overlap between invasive rainbow trout and native Atlantic salmon (Salmo salar) and brook trout (Salvelinus fontinalis) on Prince Edward Island, Canada. Analysis of landscape-level variables in 26 watersheds (14 with and 12 without rainbow trout) demonstrated that watershed slope, percent agricultural land use, and distance to the nearest rainbow trout population significantly increased the probability of rainbow trout establishment. Two independent reach-level fish community surveys were conducted by electrofishing in combination with habitat surveys. Reaches with rainbow trout had higher stream slope, Atlantic salmon were found in wider reaches with larger substrate, and brook trout were typically dominant in headwater reaches with finer substrate. Findings at multiple ecological scales illustrated that rainbow trout invasion success is positively influenced by the presence of high-slope habitat. Habitat separation of the three salmonid species indicates that competition with introduced rainbow trout may not be the most significant threat to native salmonid populations.
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Blanchet, Simon, Géraldine Loot, Louis Bernatchez, and Julian J. Dodson. "The effects of abiotic factors and intraspecific versus interspecific competition on the diel activity patterns of Atlantic salmon (Salmo salar) fry." Canadian Journal of Fisheries and Aquatic Sciences 65, no. 8 (August 2008): 1545–53. http://dx.doi.org/10.1139/f08-079.
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We conducted semi-natural experiments to measure the relative contribution of various environmental factors and intraspecific and interspecific competition with an exotic invader on the daytime and crepuscular activity levels of Atlantic salmon ( Salmo salar ) fry. We demonstrated that interspecific competition with the exotic rainbow trout ( Oncorhynchus mykiss ) significantly increases the daytime activity of Atlantic salmon. The effect of intraspecific competition on the daytime activity of salmon was half that of interspecific competition. This indicates that the effect of rainbow trout was a combination of increasing density and the identity of the competitor. We also demonstrated that the effect of rainbow trout was probably the result of territorial interference between species. Moreover, we showed that water temperature simultaneously played an important role in explaining daytime activity of Atlantic salmon. During twilight, we observed no effect of competition on salmon activity, but environmental cues other than temperature (e.g., invertebrate drift, cloud cover) became significant predictors of activity. Feeding and growth rates of Atlantic salmon were not affected by the different levels of competition. Nevertheless, the exotic species may have a major impact by exposing the native species to increased risks of daytime predation.
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Hartman, G. F., and T. G. Brown. "Use of Small, Temporary, Floodplain Tributaries by Juvenile Salmonids in a West Coast Rain-Forest Drainage Basin, Carnation Creek, British Columbia." Canadian Journal of Fisheries and Aquatic Sciences 44, no. 2 (February 1, 1987): 262–70. http://dx.doi.org/10.1139/f87-035.
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Seasonal movement of trout (Salmo clarki and S. gairdneri) into and out of three tributaries which drain areas ranging from 15 to 100 ha within the lower Carnation Creek catchment basin were monitored periodically from 1972 to 1985. The number of trout entering the three tributaries relative to total trout was as high as the number of coho salmon (Oncorhynchus kisutch) entering these tributaries relative to total coho. The percentage of the salmonid population represented by trout was highest in the two largest tributaries and lowest in the smallest. Trout were most clearly associated with nonvegetated sand and gravel bottom portions of the three tributaries. Coho were associated with this habitat too, but they also frequented portions of the tributaries that were vegetated and had a mud substrate. In the two largest tributaries, trout were represented by more age classes than were coho salmon. The paper considers some of the implications of use of small drainages by trout to habitat managers.
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Swales, S., F. Caron, J. R. Irvine, and C. D. Levings. "Overwintering habitats of coho salmon (Oncorhynchus kisutch) and other juvenile salmonids in the Keogh River system, British Columbia." Canadian Journal of Zoology 66, no. 1 (January 1, 1988): 254–61. http://dx.doi.org/10.1139/z88-036.
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Catches of overwintering juvenile coho salmon (Oncorhynchus kisutch) in the Keogh River system, Vancouver Island, were higher in two small (8 and 25 ha), shallow (mean depth 2 – 3 m) lakes and their outlet and inlet streams than in the main river, where steelhead trout (Salmo gairdneri) were predominant. Dolly Varden char (Salvelinus malma), cutthroat trout (Salmo clarki), and threespine stickleback (Gasterosteus aculeatus) were also present in the lakes. The distribution of coho salmon in the lakes was restricted largely to areas close to the bank, with few fish being captured in offshore areas or in mid-water. Apparent differences in the abundance of coho salmon between the two lakes may have been related to differences in fish community composition, with sticklebacks being particularly numerous in Misty Lake, where catches of coho salmon were lower than in Long Lake. The population density and biomass of coho salmon overwintering in Long Lake were estimated to be 176 fish/ha and 1.14 kg ha−1, respectively. The mean length of coho salmon in the lakes was greater than that of coho salmon in the tributary streams and main river, and the mean length of the salmon in the lakes generally increased with distance away from shore.
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de Eyto, Elvira, Catherine Dalton, Mary Dillane, Eleanor Jennings, Philip McGinnity, Barry O’Dwyer, Russell Poole, Ger Rogan, and David Taylor. "The response of North Atlantic diadromous fish to multiple stressors, including land use change: a multidecadal study." Canadian Journal of Fisheries and Aquatic Sciences 73, no. 12 (December 2016): 1759–69. http://dx.doi.org/10.1139/cjfas-2015-0450.
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Reduction of freshwater habitat quality due to land use change can have major impacts on diadromous fish. Partitioning this impact from other potential drivers, such as changing marine conditions and climate, is hampered by a lack of long-term data sets. Here, four decades of data were used to assess the impact of land use change on Salmo salar and anadromous Salmo trutta in the Burrishoole catchment, Ireland, one of the few index sites for diadromous fish in the North Atlantic. Land use change was found to have no significant impact on the freshwater survival of either salmon or trout. However, climate impacted significantly on the survival of salmon and trout in fresh water, with poor survival in years with wetter, warmer winters, coinciding with positive North Atlantic Oscillation values. Additionally, cold springs were associated with higher survival in trout. The addition of hatchery fish into the salmon spawning cohort coincided with low freshwater survival. Our results highlight the necessity for a broad ecosystem approach in any conservation effort of these species.
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Thomas, W. Kelley, Ruth E. Withler, and Andrew T. Beckenbach. "Mitochondrial DNA analysis of Pacific salmonid evolution." Canadian Journal of Zoology 64, no. 5 (May 1, 1986): 1058–64. http://dx.doi.org/10.1139/z86-158.
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The salmonids of Pacific North America are a group of closely related species with complex life histories and interesting distribution. Previous studies of their evolution and population structure have involved classical morphological and genetic techniques. We have analysed both intra- and inter-specific variation in mitochondrial DNA sequences of the five North American species of the genus Oncorhynchus and the rainbow trout species, Salmo gairdneri. Cleavage sites for 13 different restriction enzymes were sampled, comparing an average of 48 sites per individual, or approximately 1.7% of the genome. No obvious size variation in the 16 500 ± 500 base pair length was observed. Levels of intraspecific variation detected in the chum salmon and rainbow trout were 0.24 ± 0.23 and 0.45 ± 0.26%, respectively. This variation was population specific; no variation was detected within any of the populations sampled, suggesting the existence of population substructuring. Estimates of divergence between species range from 2.46 ± 0.72% in the coho–chinook salmon comparison to 6.88 ± 1.27% between coho and chum salmon. The phylogenetic relationship among these species, based on the levels of sequence divergence, organizes the species into three distinct groups. One group includes the pink and chum salmon while a second group contains the coho and chinook salmon, as well as the rainbow trout. The sockeye salmon are distinct from both groups. Although most of these results are in accordance with classical analyses, the relationship of the rainbow trout to the coho and chinook salmon suggests different interpretations of the evolution of life histories and morphological traits in these closely related species.
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Stewart, Donald J., and Myriam Ibarra. "Predation and Production by Salmonine Fishes in Lake Michigan, 1978–88." Canadian Journal of Fisheries and Aquatic Sciences 48, no. 5 (May 1, 1991): 909–22. http://dx.doi.org/10.1139/f91-107.
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A marked decline of alewife (Alosa pseudoharengus) in Lake Michigan during 1981–83 led to diet shifts by coho (Oncorhynchus kisutch) and chinook salmon (O. tshawytscha) from feeding primarily on large alewife to eating proportionately more immature alewives and other prey. Diets of lake trout (Salvelinus namaycush) did not change greatly during that period. Population biomass conversion efficiency averaged 24.5% for coho and 16.6% for lake trout. Chinook salmon suffered an apparent 20% decline in gross conversion efficiency of biomass (25.1 to 20.8%) and a 25% decline in average weight of sport-caught fish. We infer that chinook salmon growth was inhibited by insufficient forage available to them. A simulation of chinook salmon feeding on bloater (Coregonus hoyi) at 8 °C suggested that such behavior could lead to further declines in growth rates. Extension of modeling results to include approximations for brown trout (Salmo trutta) and rainbow trout (O. mykiss) revealed peaks in total annual salmonine predation of 71 000 t in 1983 and 76 000 t in 1987. The alewife was 70% of all prey eaten by salmonines in 1987–88. Lakewide gross production by salmonines was 15 300 t (or 0.27 g∙m−2) in 1987. Ratios of annual gross production to average monthly population biomass were 1.6 for chinook, 1.15 for coho, and only 0.6 for lake trout.
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Jansson, H., and T. Öst. "Hybridization between Atlantic salmon (Salmo salar) and brown trout (S. trutta) in a restored section of the River Dälalven, Sweden." Canadian Journal of Fisheries and Aquatic Sciences 54, no. 9 (September 1, 1997): 2033–39. http://dx.doi.org/10.1139/f97-111.
Full textAbstract:
Enzyme electrophoresis revealed a significant increase of Atlantic salmon (Salmo salar) times brown trout (S. trutta) hybrids among ascending spawners in the River Dalälven. The hybrid frequency increased from 0.1% in 1989 to 3.1% in 1995. Electrophoresis also showed a high hybrid frequency (41.5%) among parr from a river section restored for natural reproduction in 1989. Restriction fragment analysis of a species-specific region of the mitochondrial cytochrome b gene showed unidirectional hybridization as all hybrids had brown trout mitochondrial DNA genotypes. The increased incidence of hybrids was evidently a result of natural spawning in the restored river section. Massive stockings of hatchery-reared fish and environmental constraint have forced Atlantic salmon and brown trout to common spawning grounds leading to a high level of hybridization. The unidirectional hybridization may be explained by the involvement of sexually mature Atlantic salmon parr acting as sneakers.
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McCormick, Stephen D., Robert J. Naiman, and Ellyn T. Montgomery. "Physiological Smolt Characteristics of Anadromous and Non-anadromous Brook Trout (Salvelinus fontinalis) and Atlantic Salmon (Salmo salar)." Canadian Journal of Fisheries and Aquatic Sciences 42, no. 3 (March 1, 1985): 529–38. http://dx.doi.org/10.1139/f85-070.
Full textAbstract:
Anadromous brook trout, Salvelinus fontinalis, of rivière à la Truite, Quebec, were examined for physiological changes associated with smoltification, and compared with non-anadromous brook trout from the adjacent Matamek River. There were no statistical differences in plasma thyroxine concentration, gill Na+, K+-ATPase activity, hematocrit, or osmoregulatory ability between the populations. Moisture content was different between the populations, but both had the same pattern of declining moisture content as summer progressed. Silver coloration of brook trout in rivière à la Truite was associated with larger fish and higher gill Na+, K+-ATPase activity, but not with changes in plasma thyroxine concentrations, moisture content, hematocrit, or condition factor. Brook trout at high-salinity estuarine sites had greater gill Na+, K+-ATPase activity and hypoosmoregulatory ability than those from low-salinity sites. Silvering of Atlantic salmon (Salmo salar) in rivière à la Truite was associated with larger fish, higher gill Na+, K+-ATPase activity, and higher plasma thyroxine. Gill Na+, K+-ATPase activity of highly silvered freshwater Atlantic salmon was greater than that of highly silvered brook trout. Estuarine Atlantic salmon had significantly higher plasma thyroxine concentration and gill Na+, K+-ATPase activity than estuarine brook trout. Based on these physiological factors, we conclude that smoltification is undeveloped in brook trout and that estuarine residence is important for salt water acclimation and eventual seaward migration.
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ROBERTSEN, G., H. HANSEN, L. BACHMANN, and T. A. BAKKE. "Arctic charr (Salvelinus alpinus) is a suitable host for Gyrodactylus salaris (Monogenea, Gyrodactylidae) in Norway." Parasitology 134, no. 2 (October 23, 2006): 257–67. http://dx.doi.org/10.1017/s0031182006001223.
Full textAbstract:
Gyrodactylus specimens infecting both anadromous Arctic charr (Salvelinus alpinus) from River Signaldalselva (northern Norway) and resident Arctic charr from Lake Pålsbufjorden (southern Norway) were identified as G. salaris using molecular markers and morphometrics. The infection in Pålsbufjorden represents the first record of a viable G. salaris population infecting a host in the wild in the absence of salmon (Salmo salar). G. salaris on charr from Signaldalselva and Pålsbufjorden bear different mitochondrial haplotypes. While parasites infecting charr in Signaldalselva carry the same mitochondrial haplotype as parasites from sympatric Atlantic salmon, G. salaris from charr in Pålsbufjorden bear a haplotype that has previously been found in parasites infecting rainbow trout (Oncorhynchus mykiss) and Atlantic salmon, and an IGS repeat arrangement that is very similar to those observed earlier in parasites infecting rainbow trout. Accordingly, the infection may result from 2 subsequent host-switches (from salmon via rainbow trout to charr). Morphometric analyses revealed significant differences between G. salaris infecting charr in the 2 localities, and between those on sympatric charr and salmon within Signaldalselva. These differences may reflect adaptations to a new host species, different environmental conditions, and/or inherited differences between the G. salaris strains. The discovery of G. salaris on populations of both anadromous and resident charr may have severe implications for Atlantic salmon stock-management as charr may represent a reservoir for infection of salmon.
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Leduc, Antoine O. H. C., Ellie Roh, and Grant E. Brown. "Effects of acid rainfall on juvenile Atlantic salmon (Salmo salar) antipredator behaviour: loss of chemical alarm function and potential survival consequences during predation." Marine and Freshwater Research 60, no. 12 (2009): 1223. http://dx.doi.org/10.1071/mf08323.
Full textAbstract:
Many organisms rely on chemosensory cues to mediate predation risks. Recent studies have demonstrated impaired chemosensory detection ability under weak acidification. Because rainfall may lead to episodic acidification of surface water, we assessed the effects of acid rain on chemosensory alarm functions. Under natural conditions, we quantified alarm behaviour of juvenile Atlantic salmon (Salmo salar) exposed to conspecific chemical alarm cues before and following rainfall. Before rainfall, salmon were capable of an alarm response in the study streams. After rainfall, salmon from Devil’s Brook did not respond to the alarm cues whereas the detection of salmon from Catamaran Brook (a comparable stream having higher acid neutralising capacity) was maintained. To relate these findings to predator–prey encounters, we performed a second experiment where we staged encounters between prey (rainbow trout, Oncorhynchus mykiss) and predator (largemouth bass, Micropterus salmoides) exposed to acidified and unacidified rainbow trout chemical alarm cues. Trout exposed to acidified alarm cues survived for a significantly shorter amount of time than trout exposed to unacidified alarm cues, whereas no difference in overall predator behaviour was observed. Our results suggest that episodic acidification in small nursery streams may disrupt the chemical information mediated by the chemical alarm cues that can translate into higher survival costs for prey.
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Phillips, Ruth, and Peter E. Ihssen. "Chromosome banding in salmonid fish: nucleolar organizer regions in Salmo and Salvelinus." Canadian Journal of Genetics and Cytology 27, no. 4 (August 1, 1985): 433–40. http://dx.doi.org/10.1139/g85-064.
Full textAbstract:
Chromosome banding patterns obtained by silver staining (Ag-NORs) were analyzed in three species of Salmo (rainbow, brown trout, and Atlantic salmon) and three species of Salvelinus (brook trout, lake trout, and arctic char). In rainbow trout and Atlantic salmon the Ag-NORs were found at the secondary constrictions of a single chromosome pair, while in brown trout the Ag-NORs were found on the short arms of one or two of the two longest subtelocentric or acrocentric chromosome pairs. The location of the Ag-NORs was multichromosomal in the three Salvelinus species, occurring on one or both members of four to six different chromosome pairs in different individuals. The Ag-NOR sites were on the short arms of some acrocentric pairs and at the telomeres of other acrocentric pairs and one or two metacentric pairs. Chromomycin A3 positive bands were found at the same sites as the Ag-NORs in all species. In the species with multichromosomal location of Ag-NORs, polymorphisms in the size and location of the NORs were extremely common, so that almost every individual fish had a different pattern of Ag-NOR sites.Key words: banding, Salmo, Salvelinus, Ag-NORs, polymorphisms, nucleolar organizer.
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Berejikian, Barry A., R. Jan F. Smith, E. Paul Tezak, Steven L. Schroder, and Curtis M. Knudsen. "Chemical alarm signals and complex hatchery rearing habitats affect antipredator behavior and survival of chinook salmon (Oncorhynchus tshawytscha) juveniles." Canadian Journal of Fisheries and Aquatic Sciences 56, no. 5 (May 1, 1999): 830–38. http://dx.doi.org/10.1139/f99-010.
Full textAbstract:
The present study examined the effects of chemical antipredator conditioning on antipredator behavior and the relative effects of antipredator conditioning and seminatural rearing environments on postrelease survival of chinook salmon (Onocrhynchus tshawytscha). Hatchery-reared juvenile chinook salmon were exposed to extracts from conspecific tissue or to comparable stimuli from green swordtail (Xiphophorus helleri). These "injured fish" stimuli were paired with water that contained the odour of predatory cutthroat trout (Oncorhynchus clarki). Chinook salmon receiving conspecific stimuli showed higher levels of several antipredator behaviors compared with chinook salmon receiving green swordtail extracts. When the two groups of chinook salmon were tested 2 days later with cutthroat trout stimulus alone, the chinook salmon that had originally received injured conspecific stimuli paired with cutthroat trout odour spent more time motionless than chinook salmon that had received green swordtail stimuli and cutthroat trout odour. In another experiment, complex rearing treatments had a negative effect on instream survival (contrary to previous studies) that was compensated for by the application of the chinook salmon extract and cutthroat trout odour prior to release. Chinook salmon, like rainbow trout (Oncorhynchus mykiss), show antipredator behavior in response to chemical stimuli from injured conspecifics and learn predator recognition when such stimuli are paired with predator odour, improving survival in the wild.
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Stow, C. A., L. J. Jackson, and J. F. Amrhein. "An examination of the PCB: lipid relationship among individual fish." Canadian Journal of Fisheries and Aquatic Sciences 54, no. 5 (May 1, 1997): 1031–38. http://dx.doi.org/10.1139/f97-014.
Full textAbstract:
We examined data from 1984 to 1994 for five species of Lake Michigan salmonids to explore the relationship between total PCB concentration and percent lipid. When we compared mean species lipid and PCB values, we found a strong linear correlation. When we compared values among individuals, we found modest positive PCB:lipid associations in brown trout (Salmo trutta), chinook salmon (Oncorhynchus tshawytscha), coho salmon (Oncorhynchus kisutch), and rainbow trout (Oncorhynchus mykiss) collected during spawning, but positive associations were not apparent among nonspawning individuals. Lake trout (Salvelinus namaycush) exhibited no discernible PCB:lipid relationship. Our results are not incompatible with previous observations that contaminants are differentially partitioned into lipids within a fish, but these results do suggest that lipids are not a major factor influencing contaminant uptake.
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Barlaup, Bjørn T., Harald Lura, Harald Sægrov, and Rolf C. Sundt. "Inter- and intra-specific variability in female salmonid spawning behaviour." Canadian Journal of Zoology 72, no. 4 (April 1, 1994): 636–42. http://dx.doi.org/10.1139/z94-086.
Full textAbstract:
Egg pocket characteristics determined from the excavation of 29 stranded redds made by Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) in the River Vosso in western Norway are presented. The egg pockets of Atlantic salmon were, on average, deeper (27.0 vs. 14.8 cm) and contained more eggs (707 vs. 148) than those of brown trout. An adaptive "test-digging" behaviour was indicated by the finding of a significant association between false redds and gravel classified as low-quality spawning substrate. Based on fecundity data and number of eggs per redd, it was estimated that individual Atlantic salmon and brown trout deposited their eggs in 8.4 and 5.7 different redds, respectively. A 100-year data series indicates that the high proportion of stranded salmon redds (23%) can be attributed to the high frequency (27% of the years) and random occurrence of low water discharge rates. Estimated probabilities of extinction and associated variances in fitness assigned different spawning behaviours suggest that the temporal and spatial variation in offspring survival produces a selective advantage for the multiple-redd tactics over the single-redd tactic. Moreover, in contrast to iteroparous salmonids, semelparous Oncorhynchus species invariably place all their offspring in one redd. This dichotomy can most likely be ascribed to the provision of parental care (i.e., redd guarding) by semelparous salmonids.