Reproductive Cycle and Fecundity in Natural Population of Edible Freshwater Crab, Oziothelphusa senex senex (Fabricius, 1798) (Decapoda: Brachyura)

Abstract

Rapid growth rate, high meat content, excellent palatability and resistance to white spot virus favored the culture of crab species in aquaculture industry. This study examined the natural reproductive cycle of edible fresh water crab Oziothelphusa senex senex by monthly measurement of ovarian index and histological examination of the gonads of the animals and determination of berried and young-one-bearing females collected monthly. The number of berried and young-one-bearing females was significantly higher in September-October. However, a small number of ovigerous and young-one bearing females were observed throughout the year. We also observed a breeding peak in September-October using ovarian index as marker. Within study catchments, mean number of eggs and young ones was 130 and 120 during September and 132 and 118 in October. The number of eggs spawned in the smallest (17 g body weight) crab is 80 and the largest (44 g body weight) crab is 140. We also observed a positive correlation between the numbers of eggs spawned and body weight. Surprisingly, no correlation was found between the breeding cycle and the environmental factors such as temperature, photoperiod and rain fall. The lesser dependence on climatological factors for the completion of reproduction in the crab indicates greater potential of this species for crab fishery.