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• Main Authors: Dr. James, R. Lovvorn
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: 99; 459.00; Bering Sea; Lawrence Island; Snow crab; St Lawrence Island; St Matthew Island
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.577.8797; http://doc.nprb.org/web/07_prjs/713(35).pdf

Life history, ecology and fluctuations in BSAI crab stocks Summary of Proposed Work: Water temperature is key to the distributions, growth, and reproduction of crabs, and is potentially a valuable predictor of climate warming effects on crab fisheries. In the Bering Sea, the main concentration of snow crabs of marketable size has shifted northward from Bristol Bay to northwest of St. Matthew Island, with further expansion likely. In our 2006 surveys, snow crabs were abundant north and south of St. Lawrence Island (SLI), but were less than legal size of 78 mm. From north to south, mean carapace width increased by 83 % (23-42 mm), and minimum size of mature females by 24 % (45-56 mm). More small crabs in the north may result from temperature limits on growth, which reduces cannibalism on smaller sizes. Our low catches of groundfish, and predominance of snow crabs as predators, suggest that crab size structure in that area is more affected by cannibalism than by predatory fish. To predict northward expansion of snow crab fisheries with climate warming, we will (a) determine growth rates and diets of settled juveniles through adult stages north and south of SLI, and (b) model the energetics of growth as a function of diet and temperature. To test the hypothesis that crab size structure and fisheries in the northern Bering Sea are controlled by temperature, we will compare predicted growth and size structure to data from our study areas, and to historical data from the ChukchiSea and north of St. Matthew Island.