Preliminary Stock Assessment of The Chesapeake Bay Blue Crab Population

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Knotts, Karen Sue
Rothschild, Brian J.
A preliminary stock assessment using data from a commercial fishery survey was completed. The maximum average attainable size (Linf) was found to be 174.25 mm (6.9 in) for males, and 171.7 mm (6.8 in) for females. The von Bertalanffy growth coefficient (K) was determined to be 0.83 for males and 0.57 for females. Yield-per-recruit analysis indicated that a significant amount of yield-per-recruit is lost if males are fished before reaching approximately 145 mm (5.7 inches). Results for females show that the size at first capture should be approximately 124 mm (5 inches), after which the yield-per-recruit gained by waiting is minimal. The nature of the recruitment-stock relationship could not be characterized in this study; however, results indicate that a relationship does exist. A comparison of early and late season catch curves indicated surplus production of biomass in the 1987 pot fishery. The potential use of change in sex ratios estimators for stock assessment is discussed.