A Method to Estimate the Stock-Recruitment Relationship of Shrimpsl

A procedure is proposed by which recruit numbers and parental biomass of shrimps stocks can be derived, given a series of catch-per-effort data and estimates of a few ancillary variables. In the Gulf of Thailand, shrimp recruitment decreased with decreasing egg production, but increased with decreasing total (mainly fish) standing stock. The net result of these counteracting effects was an overall increase in shrimp recruitment, attributable to a greatly reduced prerecruit mortality. .~ Although shrimp stocks throughout the world support highly profitable fisheries, little is known of the biology of the various species that support these fisheries, with the possible exception of the Penaeus species of the northern Gulf of Mexico. Least is known about the population dynamics of tropical penaeid shrimps that greatly contribute to the economy of many developing countries. Of the various factors that determine the yield of a fishery, recruitment certainly is the most evasive (Marr 1976). This is true particularly in the case of shrimps, the stock-recruitment relationships of which appear rarely to have been established. The present contribution is an attempt to identify the stock-recruitment relationship of a commercially exploited stock of penaeid shrimps, and is based mainly on catch/effort data from the Gulf of Thailand demersal trawl fishery. The analysis is preliminary and relies heavily on a set of assumptions that were necessary to extract any information from the crude data presently available.