Bering Sea | Fishes and Fish Habitats
Effects of shell condition and temperature on the size-weight relationships of Alaskan commercially fished crab stocks and derived biomass estimates Presenter: Jonathan Richar , jon.richar@noaa.gov, US Dept Commerce, NOAA, AFSC The modeled length-weight relationship is a critical component in expanding survey-derived data to create population estimates for eastern Bering Sea crab stocks. Current procedures assume this relationship to be constant across a range of both crab physiological parameters, and environmental conditions for the purpose of creating biomass estimates. We assessed effects of shell condition on length-weight relationships for male Bristol Bay red king crab and St. Matthew blue king crab, and both male and female eastern Bering Sea opilio and Bairdi crab, and effects of environmental temperature on that for male Bristol Bay red king crab only. Population biomass estimates were derived using calculated model parameters, and compared to estimates calculated using the current fixed parameters. Old shell crab were found to be heavier for a given size in all models, with some variability in the slope of the size-weight relationship across sizes. New shell red king crab were found to weigh less for a given size in cold years. Relative to estimates calculated using the current standard models for these stocks, population biomass estimates were modestly larger with some interannual variability. These results suggest that it is advisable to reconsider and update current biomass estimation procedures used in stock assessment.
Alaska Marine Science Symposium 2023 205
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