Spatiotemporal trends in Tanner crab (Chionoecetes bairdi) size at maturity

Spatiotemporal trends in Tanner crab (Chionoecetes bairdi) size at maturity

R.S. Otto and D. Pengilly

Spatiotemporal trends in Tanner crab (Chionoecetes bairdi) size at maturityThis is part of Crabs in Cold Water Regions: Biology, Management, and Economics
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Description

The Tanner crab, Chionoecetes bairdi, is widely distributed on the continental shelf and slope of the eastern Bering Sea (EBS). Commercially important concentrations occur around the Pribilof Islands and in Bristol Bay. Two distinct management areas, divided at 167.25ºW, have been advocated based on a discontinuity in the east-to-west trend of decreasing size at maturity for female crabs observed during 1975-1979 summer trawl surveys. This division would separate Pribilof Islands from Bristol Bay grounds. Genetic sampling of isozymes supported a two-stock hypothesis, but the latter was too sparse to establish whether a cline, as opposed to a discontinuity, exists. We examine latitudinal, longitudinal, and depth-related trends in size at maturity for female and male Tanner crabs collected in trawl surveys of the EBS during the summers of 1975-2000. The 1975-2000 data show a clinal trend in size at maturity related to depth and variation in regional size at maturity trends across survey years that do not support a two-stock hypothesis.

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