Gametogenic Cycle of the Oysters Pinctada capensis (Sowerby III, 1890) and Saccostrea cucullata (Born, 1778) (Class Bivalvia) in Inhaca Island, Southern Mozambique: A Subsidy for Bivalve Culture in the Region

Abstract

This study describes reproductive aspects of the Pinctada capensis (pearl oyster) and Saccostrea cucullata (rocky shore oyster) in Inhaca Island, southern Mozambique (Western Indian Ocean). Adult oysters were collected monthly over two years within seagrass banks for P. capensis and rocky shore habitats for S. cucullata. The animals were evaluated using biometric and histological analyses of the gonads. Of the total population, females were predominant among larger individuals (>55 mm) and males were more dominant among smaller individuals (<55 mm) for both species. The sex ratio was (1 M–1.5 F) for Pinctada capensis and (1 M–1.6 F) for Saccostrea cucullata. Five gonad maturation stages were identified: indifferent, developing I, developing II, ripe and spent. The size at first maturity was mm and 26.2 mm for pearl oysters females and males, respectively, whereas for rocky shore oysters was 32.8 and 28.3 mm for females and males, respectively. We conclude that the reproduction of S. cucullata and P. capensis occurs mainly in summer, with a short resting period in winter, when many oysters are in the indifferent stage. These results provide valuable information to fisheries for management of both species in the area.