Size at Maturity and Spawning Periodicity of the Mud Crab Scylla Serrata (Forskal) in the Negombo Estuary

Abstract

Ahslrnct : Sonie aspects of reproductive biology of the mud crab, Scylln serrnta in the Negonlbo estuary were studied by screening bi-weekly samples over a period of one year. The study revealed that the size of the female crab at first maturity was 12 cm and the estimated pre-spawning and post-spawning fecundities were around 3 and 1.5 nlillion respectively. The ova mature at the size of about 3001im and are found in three batches indicating a partial spawning behaviour. Spawning occurs in two seasons, April and August. The sex ratio was uneven in most size groups and in most months of the year. About 85% of the comn~ercial catches comprise immature females.

Reproductive biology of the orange mud crab Scylla olivacea (Herbst, 1796) from the Pichavaram mangroves of south-east India

“…Pre-spawning fecundity was estimated by counting the number of ova present in the mature ovary (Jayamanna and Jinadasa, 1993). Ovaries in stages III and IV were carefully removed and fixed in Gilson fluid.…”

Fishery characteristics and abundance estimates of the mangrove crab Scylla serrata in southern Tanzania and northern Moçambique

“…Those authors also found that sexual activity peaked at 120-180 mm CW and declined in individuals > 190 mm. Size-at-50%-maturity of S. serrata is 120 mm CW in Sri Lanka (Jayamanna and Jinadasa 1993), 123 mm CW in South Africa (Robertson and Kruger 1994) and 150 mm CW in the Northern Territory of Australia (Knuckey 1996). As maturation parameters are geographically variable, similar studies would need to be conducted in Tanzania and Moçambique in order to determine the size at sexual maturity.…”

Study on the Effect of Stocking Density on Brood Stock Development of Mud Crab Scylla serrata in Brackishwater Earthen Ponds

“…Though there is controversy about the spawning time of Scylla serrate in various region, preferably in Bangladesh, it has been observed that though crab spawn are available year round at different degrees but its abundance Is mostly observed during March-June. Jayamanna and Jinadasa (1993) stated that mud crab spawn all through the year with two peak, one in December-March and another in September-November. However considering the above observation of spawning time and frequency of spawning it can be concluded that the period of experimented in the present study does not have any impact on maturity study of fnud crab.…”