Reproductive characters of the oyster Crassostrea brasiliana from mangroves of Cananéia estuary, São Paulo, Brazil

Abstract

The purpose of this paper was to identify the gonadal development phases of the oyster Crassostrea brasiliana (Lamarck, 1819) from Cananéia mangroves. This study was conducted from August to November 1998. The oyster's height ranged between 20 and 96 mm and the total weight, between 1.66 and 88.50 g. Among the sampled oysters, 54.2% were males, 41.4%, females and 0.6%, hermaphrodites. The sex of 3.7% of the oysters could not be determined because of the very sparse gonadal tissue. The c1assification employed was: I) prematuration; II) maturation; III) elimination; IV) advanced spawning; V) resting stage. During August and September most of the animaIs was in stages I and II and from October to November the number of spawning animals increased (III and IV). The oocytes diameter ranged between 20 and 120 µm with the highest frequency in the c1ass 50 - 59 µm. In stages I and II, oocytes greater than 100 µm were observed. The condition index was higher in stages II and III. The occurrence of the trematode Bucephalus sp. was registered in the mantIe of one histologicaly analyzed oyster. The results obtained in this work shall contribute with basic information to a rational exploitation program in Cananéia region, SP, as well as to induce spawning in laboratory.