نتایج جستجو برای: salmon fish
تعداد نتایج: 113115 فیلتر نتایج به سال:
—If hatchery-reared salmon delay emigration after release, they may compete with wild salmon in freshwater rearing habitat. We measured the densities and size distributions of ocean-type juvenile Chinook salmon Oncorhynchus tshawytscha in two rearing areas downstream of a hatchery in the Sacramento River, California, before, during, and after two large releases in both 2001 and 2002. Densities ...
We estimated bias-corrected mean fork lengths of gillnet-caught chum salmon using a size selectivity estimate of the gillnet to test how the bias correction affects the estimated temporal pattern of chum salmon body size, during 1971–1994 and 1994–2007. Results showed bias-corrected mean fork lengths were smaller than uncorrected means. Therefore, when examining ontogenetic changes in fish size...
Modeling Parasite Dynamics on Farmed Salmon for Precautionary Conservation Management of Wild Salmon
Conservation management of wild fish may include fish health management in sympatric populations of domesticated fish in aquaculture. We developed a mathematical model for the population dynamics of parasitic sea lice (Lepeophtheirus salmonis) on domesticated populations of Atlantic salmon (Salmo salar) in the Broughton Archipelago region of British Columbia. The model was fit to a seven-year d...
BACKGROUND Sea lice infection is the most expensive disease factor for Atlantic salmon sea-cage farming. For triploid salmon to be accepted as a commercial possibility, investigation of susceptibility of triploid salmon to sea lice infection is a fundamental milestone. The susceptibility of diploid and triploid salmon to infection with Lepeophtheirus salmonis was examined in a tank trial in Sco...
Body dimensions and swimming speeds of Atlantic salmon (Salmo salar) and chinook salmon (Oncorhynchus tshawytscha), ranging in weight from less than 1 to over 6 kg, were used to calculate the power needed to overcome drag. Fish were kept in 15 m×15 m×15 m deep cages, stocked under typical industrial conditions and fed to apparent satiation by broadcasting feed over the water surface. The averag...
The purpose of this study is to quantify the importance of turbulent kinetic energy, strain, water velocity, fish depth, and fish distance to wood to the decision making process of overwintering coho salmon during habitat selection. Although many studies have evaluated this habitat selection of salmon, few have included hydraulic variables in the equation, while recent research indicates that t...
The Southeast Alaska Coastal Monitoring (SECM) project has been sampling juvenile salmon (Oncorhynchus spp.) and associated biophysical parameters in northern Southeast Alaska (SEAK) annually since 1997 to better understand effects of environmental change on salmon production. A pragmatic application of the annual sampling effort is to forecast the abundance of adult salmon returns in subsequen...
Fish fauna of small coldwater streams of North America typically include trout and salmon, sculpins, minnow, sticklebacks, suckers, or lampreys (Hocutt and Wiley 1986). Standard sampling protocols provided herein apply primarily for trout and salmon because of their sport and commercial values (Johnson et al. 2007). As interest in nonsalmonid species grows, further development of sampling metho...
Highly unsaturated fatty acid (HUFA) synthesis in Atlantic salmon (Salmo salar) was known to be influenced by both nutritional and environmental factors. Here we aimed to test the hypothesis that both these effectors involved similar molecular mechanisms. Thus, HUFA biosynthetic activity and the expression of fatty acyl desaturase and elongase genes were determined at various points during an e...
Selenium (Se) is an essential element for animals, including fish. Due to changes in feed composition for Atlantic salmon (Salmo salar), it may be necessary to supplement feeds with Se. In the present work, the transfer of Se and Se species from feed to muscle of Atlantic salmon fed Se supplemented diets was studied. Salmon were fed basal fish feed (0.35 mg Se/kg and 0.89 mg Se/kg feed), or fee...
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