ANNUAL REPRODUCTION AND GROWTH OF ADULT CRABS CHASMAGNATHUS GRANULATA (CRUSTACEA, BRACHYURA, GRAPSIDAE)

LÓPEZ GRECO, L.S. Y E.M. RODRIGUEZ

CAHIERS DE BIOLOGIE MARINE

Año: 1999 vol. 40 p. 155 - 164

0007-9723

Somatic growth and gonadal maturation of Chasmagnathus granulata (Grapsidae, Sesarminae) were studied throughout one year. Spawning and moulting were recorded under controlled laboratory conditions, while gonadosomatic (GI) and hepatosomatic (HI) indexes were estimated from crabs monthly sampled at field (Samborombón Bay, Argentina). Adult females may have at the most four broods during the reproductive season (September to March i.e. Spring- Summer), with one month of incubation period. Brooding and larval eclosion are correlated with the lunar cycle, a fact which favour the larval dispersion to the sea. Females can moult during the reproductive period, with a higher percentage than males. The highest percentage of moulting was observed for both sexes after the reproductive season during April and May (autumn). The seasonal change of the gonadosomatic index that the gonads begin to develop in winter (June to August) after the moulting period.