Do Silent Ships See More Fish? Comparisons of Walleye Pollock Backscatter Recorded by a
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منابع مشابه
The influence of ontogeny, physiology, and behaviour on the target strength of walleye pollock (Theragra chalcogramma)
Variability in echo intensities from aquatic organisms is caused by physical factors associated with the transmission of sound through water, and by biological factors associated with the ontogeny, physiology, and behaviour of targets. Acoustic-based density estimates depend on accurately characterizing reflected or backscattered sound from any species of interest. Digitized lateral and dorsal ...
متن کاملA method for evaluating the effects of biological factors on fish target strength
Understanding the relationship between fish biology and target strength potentially improves the accuracy of acoustic assessments. The effects of individual biological factors (e.g., length, tilt, and depth) on backscatter amplitude have been examined, but the relative contribution of each factor has not been quantified. Dimensionless ratios, which facilitate comparison of disparate quantities,...
متن کاملRegional, interannual and size-related variation of age 0 year walleye pollock whole body energy content around the Pribilof Islands, Bering Sea
Mean whole energy content (Ewb) of age 0 year walleye pollock Theragra chalcogramma was 19·928 KJ g 1 dry mass in 3943 fish collected from different habitats around the Pribilof Islands frontal structure, south-east Bering Sea, during September 1994–1996 and 1999. It varied, however, with habitat type. Fish residing offshore had higher Ewb than fish residing inshore of the frontal regions. Age ...
متن کاملA multispecies virtual population analysis of the eastern Bering Sea
The eastern Bering Sea shelf supports a large biomass of several groundfish populations, particularly walleye pollock (Theragra chalcogramma). The main trophic interactions between dominant groundfish populations in this region involve walleye pollock as prey. A multispecies virtual population analysis model (MSVPA) covering the period 1979–1995 has been parameterized for the eastern Bering Sea...
متن کاملPotential acoustic discrimination within boreal fish assemblages
Differences in the acoustic characteristics of forage fish species in the Gulf of Alaska and the Bering Sea were examined using Kirchhoff ray-mode (KRM) backscatter models. Our goal was to identify species-specific characteristics and metrics that facilitate the discrimination of species using acoustic techniques. Five fish species were analyzed: capelin (Mallotus villosus), Pacific herring (Cl...
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