Predation and the abundance of juvenile blue crabs : a comparison of selected East and Gulf Coast (USA) studies

Although blue crab postlarvae have recently been found to be 10-100 times more abundant along Gulf coast (AL, MS and TX) than along Atlantic Coast (DE, VA, NC, and SC) estuarine nursery habitats, commercial landings have historically shown the Chesapeake Bay to produce the greatest blue crab harvests. To factor out the possibility that unequal fishing effort accounted for differences in landings, fisheries independent abundances of juvenile crabs produced using similar, quantitative sampling methods, were tabulated and analyzed. These data showed that juvenile blue crab abundances are of the same order of magnitude along both the Atlantic and Gulf coasts. This suggests that either emigration or survival rates of newly metamorphosed young crabs must differ between Gulf and Atlantic coast locations. Surveys of both published and unpublished data from experimental studies using similar methods for assessing predation intensity show higher predation risk on the Gulf coast. This is consistent with results found for other crab species in previous work, and we conclude that differentially higher predation on the abundant, newly metamorphosed juvenile crabs in the Gulf of Mexico appears to best explain the overall similarities in juvenile abundance in Gulf and Atlantic Coast estuaries.