Abstract

The queen conch, Strombus gigas, is a large marine gastropod that is widely distributed in sea grasses and on sandy bottoms throughout the Caribbean Sea. For centuries it has been one of the most valuable fisheries resources in the region, resulting in heavy stock exploitation. A variety of methods have been used to assess stock status relative to fishing pressure, however there are only a few studies that incorporate conch life-history and fishery parameters to guide the management oí the species. Queen conch vital rates and size/age structure depend on growth rate and body size, and to some extent on sex ratio.\Queen conchs grow in shell length only until the onset of sexual maturity; adults do not grow in shell length but in shell lip thickness. Furthermore, individuals of the same age differ considerably in size; thus age and length alone do not provide sufficient information on fecundity or natural mortality, which are important elements used in the design of management strategies. Size increments (in length and lip thickness) from 458 marked and recaptured individuals were used in this study to develop a stage-classified demograpbic model to project different scenarios of mortality, fecundity and stage-structured (size-age) harvest; and to test the sensitivity of the rate of population increase (Ro) to changes in those parameters.

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