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Atlantic Salmon Fry (atlantic + salmon_fry)

Distribution by Scientific Domains

Earth and Environmental Science	75%

Selected Abstracts

Habitat-mediated size selection in endangered Atlantic salmon fry: selectional restoration assessment

EVOLUTIONARY APPLICATIONS (ELECTRONIC), Issue 4 2010
Michael M. Bailey
Abstract Preservation of adaptive variation is a top priority of many species restoration programs, but most restoration activities are conducted without direct knowledge of selection that might foster or impair adaptation and restoration goals. In this study, we quantified geographic variation in selection on fry size of endangered Atlantic salmon (Salmo salar) during the 6-week period immediately following stocking in the wild. We also used a model selection approach to assess whether habitat variables influence patterns of such selection. We found evidence for significant size-selection in five out of six selection trials. Interestingly, the strength and pattern of selection varied extensively among sites, and model selection suggested that this variation in phenotypic selection was related to geographic variation in the presence of large woody debris and the slope of the stream gradient. The strong selection differentials we observed should be a concern for endangered salmon restoration, whether they reflect natural processes and an opportunity to maintain adaptation, or an indicator of the potentially deleterious phenotypic consequences of hatchery practices. [source]

Habitat selection by juvenile Atlantic salmon: the interaction between physical habitat and abundance

JOURNAL OF FISH BIOLOGY, Issue 4 2005
R. D. Hedger
The effect of physical river habitat variables on the distribution of juvenile Atlantic salmon Salmo salar L. in the Rivière de la Trinité, Québec, Canada, was examined using generalized additive modelling. A survey of Atlantic salmon fry and parr densities and habitat variables (flow velocity, water column depth and substratum size) was conducted in the summer months from 1984 to 1992. Clear patterns of habitat use existed: specific ranges of habitat variables were selected, with parr preferring greater velocities, depths and substratum sizes than fry. There was a large variation, however, in juvenile densities for given velocities, depths or substratum sizes, with this variation being greatest in optimal habitats. On examination of an individual year, interaction between the variables was found to explain some of the variation. On a year-to-year basis the juvenile Atlantic salmon population was found to exhibit an ,Ideal Free Distribution', which resulted in greatest variation in optimal habitats with year-to-year changes in population abundance. [source]

Dietary menadione nicotinamide bisulphite (vitamin K3) does not affect growth or bone health in first-feeding fry of Atlantic salmon (Salmo salar L.)

AQUACULTURE NUTRITION, Issue 6 2009
C. KROSSØY
Abstract The aim of the present study was to elucidate if increasing levels of added vitamin K in the feed influenced fish growth, health or the incidences of bone deformities in Atlantic salmon (Salmo salar L.) from onset of start feeding to ,100 g in freshwater. Duplicate groups of Atlantic salmon fry (,0.20 g) were fed eight levels (0, 2.5, 5, 7.5, 10, 15, 20 and 50 mg menadione kg,1) of the vitamin K derivate menadione nicotinamide bisulphite (MNB) in a regression design for 28 weeks. All fish maintained high growth rates throughout the experiment, and showed no significant differences in specific growth rate, condition factor, whole body proximate analysis, blood coagulation time, vertebra morphology or mechanical properties of vertebrae. We found a dose-response between whole body vitamin K concentration and the dietary MNB supplementation level. Analysis of liver ,-glutamylcarboxylase activity revealed significant dose-dependent differences between groups given the 0, 10 and 50 mg MNB kg,1 diets. In conclusion, Atlantic salmon seems to require low levels of dietary vitamin K, and the amount of vitamin K found naturally in the presently used feed ingredients may be enough to maintain optimal growth, health and bone strength in Atlantic salmon fry from start feeding. [source]

Hypervitaminosis A in first-feeding fry of the Atlantic salmon (Salmo salar L.)

AQUACULTURE NUTRITION, Issue 1 2002
R. ØRNSRUD
Atlantic salmon fry were reared on a fishmeal based diet with increasing levels of vitamin A (VA) (6, 122 and 938 mg retinol kg,1 dry feed) from startfeeding and for 14 weeks. Signs of VA stress, such as reduced fat stores, liver size and growth, were found for groups receiving 122 and 938 mg retinol kg,1. Signs of vitamin A toxicity, such as increased mortality, abnormal vertebral growth, and reduced growth, were found for groups receiving 938 mg retinol kg,1. These results suggest that excess VA in the early life stages of Atlantic salmon is deleterious for normal development. [source]