Contributions to the knowledge of the sea-bob shrimp (Xiphopenaeus kroyeri Heller, 1862) biology and fishery in the Sao Paulo State littoral, Brazil

Abstract

One of the most important species captured in the Sao Paulo State coast is the sea-bob-shrimp (Xiphopenaeus kroyeri), with economic and social weightness. In this study about the fishery and biology of X. kroyeri, based on data furnished by the Cooperativa Mista de Pesca Nipo-Brasileira, in Guarujá district, the efficiency and yield analysis were developed according to SANTOS (1978, 1992, 1995, 1996). It was verified that the big boats of the fleet presented relative efficiency four times greater than that of the small ones, which should be take into account in total annual efforts; the maximum CPUE (catch per effort unit) in June is due to recruitment and in October, to a spawning spatial concentration; the interruption of the fishery in March and April did not protect the shrimp population; the narrow continental shelf can explain why the species does not occur yonder the center of Santa Catarina State littoral or in Rio de Janeiro State northern littoral. The estimations of the yield function parameters resulted in: capture minimum age (t_m) = 0.67 year; first spawning age (t_r) = 1 year; recruitment age (t_R) = 0.67 year; coefficient of natural mortality (M) = 0.6; recruitment maximum rate (R*) = 4.0; parameter of homeostasis (h) = 0.00065; coefficient of catchability (q) = 0.0030 for unit of effort = 1,000 hours of trawl. The maximum sustainable yield was estimated to the Sao Paulo State littoral in 6,986 ton for an effort of 354,000 hours and CPUE of 19.7 kg/h, and critical effort of 1,200,000 hours.