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Growth and Recruitment of Juvenile
Chesapeake Bay Blue Crab
Recent declines in Chesapeake blue crab (
Callinectes sapidus) landings, and evidence for declines in spawning stock and recruitment have prompted actions for increased regulation of harvest, and improved scientific understanding of factors that control blue crab fishery yields. Management targets and thresholds are based upon age-based stock assessments, which depend upon unsubstantiated assumptions and models of growth, mortality and recruitment rates.
Despite arguments that blue crabs may have once achieved longevities greater than 5 years, our research shows that the current fisheries and the stock upon which they rely are governed by dynamics of juvenile and adult crabs < 2.5 years of age. We hypothesize that yield dynamics in the peeler and hard crab fisheries are mostly dependent upon new recruits: those cohorts of blue crab that are just attaining harvestable sizes.
Lipofuscin (LF)-based age determination of blue crabs will be used to measure the rate at which juvenile blue crabs grow and recruit into Chesapeake Bay peeler and hard crab fisheries during summer and fall months. This will be used to develop a temperature-based growth model for juvenile blue crabs. The growth model will test our hypothesis and assist managers in better predictions of fishery recruitments from monitored juvenile size distributions.
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David H. Secor
H. Rodger Harvey
Chesapeake Biological Laboratory
University of Maryland Center for Environmental Science
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