Acoustic surveys are routinely used to assess fish abundance. To ensure accurate population estimates, the characteristics of echoes from constituent species must be quantified. Kirchhoff-ray mode (KRM) backscatter models were used to quantify acoustic characteristics of Bering Sea and Gulf of Alaska pelagic fish species: capelin (Mallotus villosus), Pacific herring (Clupea pallasii), walleye p...

We introduce a new method that uses generalized linear mixed models to infer the depth distribution of pelagic fishes. It uses existing data from research surveys and observers on commercial vessels to estimate changes in catchability when longline fishing gear is lengthened to access deeper water. We infer the depth distribution of catchability for 37 fish species that are caught on pelagic lo...

Knowledge of movement patterns is critical to the management and conservation of inland salmonids. We studied the movements of Bonneville cutthroat trout (Oncorhynchus clarki utah) in a drainage in western Wyoming, USA. Our objectives were to (i) characterize the postspawning movement patterns of adult Bonneville cutthroat trout, (ii) contrast postspawning and summer movement patterns, and (iii...

A universal approach by Laplace transform to the variational iteration method for fractional derivatives with the nonsingular kernel is presented; in particular, the Caputo-Fabrizio fractional derivative and the Atangana-Baleanu fractional derivative with the non-singular kernel is considered. The analysis elaborated for both non-singular kernel derivatives is shown the necessity of considering...

The upstream effects of reservoirs on stream fish assemblages were highly localized in 3rdthrough 5thorder streams in the Great Plains, USA. Streams that differed in connectivity to reservoirs were sampled at their confluences with a river or reservoir and between the confluence and the stream’s origin. Sites at confluences had higher total, nonnative, and reservoir species richness than middle...

Billions of hatchery salmon smolts are released annually in an attempt to mitigate anthropogenic impacts on freshwater habitats, often with limited success. Mortality of wild and hatchery fish is high during downstream and early ocean migration. To understand changes that occur during migration, we examined physiological and endocrine changes in Atlantic salmon (Salmo salar) smolts during hatch...

The adipose fin on fishes is a highly conserved and enigmatic, small, non-rayed fin that has persisted from the Mesozoic on some basal teleosts such as salmonids. Using juvenile steelhead, Oncorhynchus mykiss (Walbaum, 1792), ranging from 5 to 18 cm standard length, we experimentally test the effects of adipose fin removal on swimming performance in a variable velocity flow chamber and quantify...