(Fishery na biology aspects of the Sciaenidae Isopistus parvipinis (Curvier, 1830) present in the rejected of the sea bob shrimp artisanal fishery, São Paulo, Brazil.)

Abstract

A total of 3.450 exemplars of lsopisthus parvipinnis from 87 samples from the fishery directed to the sea-bob shrimp (between 4 and 15 meters deep) were analyzed between 1978 and 1981. The samples were obtained in four places at the coast of São Paulo State: Cananéia, Peruí­­be, Perequê (Guarujá) e Ubatuba. The size range of highest vulnerability for the species in this fishery was between 5.0 and 9.0 cm. The length classes availability to the fishery varied depending on the season or sampling place. The recruitment period of the species in the sea-bob shrimp artisanal fishery was long, beginning in the summer and reaching the winter. The sex-ratio observed was 1 male to 1.6 female. The estimated length for the macroscopic sex determination was 10.7 cm to the species (in a level of 50%). The fishery is accomplished in an area that can be considered like growth area to the species, where happens a high mortality of juveniles. It seems that the I. parvipinnis population migrates perpendicularly to the coast because of the growth of the individuals. The length-weight relationship formula was determined as: Wt = 7.62.10^-3 Lt^3.098385.