Maturity and breeding of the mud crab,Scylla serrata (Forskal) (Decapoda: Brachyura: Portunidae)

Abstract

Females of Scylla serrata attained sexual maturity after reaching 80 mm carapace width and above. Fifty per cent of females at size range 91-100 mm carapace width were sexually mature. The growth rate of abdomen width or length with respect to either carapace width or length was generally at much higher side in mature females than in the immature specimens. A sharp transition at 80 mm carapace width indicated the morphological changes accompanied with the sexual maturity. The relationship between abdomen allometry and carapace measurements was highly significant (P<O·OOI). Scylla serrata although bred all through the year, exhibited two peaks of breeding, one in between December-March and another in September-November. The sex-ratio in two biotopes varied considerably with the breeding season and size of the female population. The females were found to be in berried state in inshore and off-shore waters of Karwar at 90 mm carapace width and above. Spawning of Scylla serrata was found to occur only in inshore and off-shore but not in backwaters.

Life-history, movement, and habitat use of Scylla serrata (Decapoda, Portunidae): current knowledge and future challenges

“…In accordance with the findings of ovigerous mud crabs in bottom trawls while fishing for prawns offshore, it was concluded that female mud crabs move long distances (up to [95 km) offshore for spawning (Hill, 1994). Other studies noticed ovigerous females in shallow lagoons, bays, and inlets (Arriola, 1940;Brick, 1974;Prasad & Neelakantan, 1989), indicating that the spawning migration might depend on hydrological features rather than topographic features. However, to date it was not possible to track the exact movement of gravid females to their spawning grounds.…”

“…The different developmental stages of the gonads are shown in Tables 4 and 5. In both sexes, the maturity stages can be identified by different size and coloration of the gonads (Shanmugam & Bensam, 1980;Prasad & Neelakantan, 1989;Poovachiranon, 1992;Robertson & Kruger, 1994;Quinitio et al, 2007).…”

“…Mud crabs are top benthic predators and feed on sessile or slow-moving benthic macroinvertebrates, mainly gastropods, crustaceans, and molluscs, as shown by foregut content analyses conducted on populations in Australia, Africa, and India (Hill, 1976;McLaren, 1977;Prasad & Neelakantan, 1988). The composition of food items changes as the mud crab grows (Prasad & Neelakantan, 1988).…”

“…The composition of food items changes as the mud crab grows (Prasad & Neelakantan, 1988). In small juveniles (\70 mm CW), foregut contents were dominated by detritus while in larger juveniles ([80 mm CW) and adults, crustaceans and fish were the dominant food items.…”

Taxonomy, length-weight relationship, food and feeding habits of flower moon crab Matuta planipes Fabricius, 1798 from coastal waters of Gopalpur, Odisha, India

“…Various species of crabs studied earlier viz., Scylla serrata (Hill, 1976;Joel and Raj, 1986;Prasad and Neelakantan, 1988); Callinectus sapidus (Laughlin, 1982); Scylla tranquebarica (Joel and Raj, 1986) and Thalamita crenata (Cannici et al, 1996) were found to consume mixed diets of polycheates, crustaceans, molluscs and fishes. Whenever food was found in stomach, it always consisted of a mixture of various groups.…”