Reproductive biology of the female deepwater crab Charybdis smithii (Brachyura, Portunidae) from the Indian seas.

Abstract

Reproductive biology of the potentially commercial deepwater crab Charybdis smithii was studied. Samples were obtained during exploratory cruises made in Indian seas by the Fishery Oceanographic Research Vessel Sagar Sampada. Samples were obtained from both pelagic and benthic realms. Five stages of sexual development, namely, immature, early maturing, late maturing, ripe and spent, were distinguished based on morphological and histological examination of the ovary. Size at first maturity at 50% level for females was 48.7 mm carapace width (cw). However, the smallest ovigerous female encountered was 45 mm cw. Individual fecundity was relatively low (1,343-42,209) compared to other brachyuran crabs but eggs were larger. The crab population occupying the pelagic realm was exclusively in non-breeding phase, whereas breeding stock were found only at the bottom.