FAO/SIDP Species Identification Sheets Scylla serrata (null, 2001) FAO Names EN - Indo-Pacific swamp crab; FR - Crabe de palétuviers; SP - Cangrejo de manglares. Synonyms Cancer serratus Forsskål. Diagnostic Features Carapace smooth, with strong transversal ridges. Gastric zone on the carapace with a deep H-shaped groove. Front with 4 broad lobes, all more or less in line with each other; 9 broad teeeth on each anterolateral margin, all them with similar size and projecting obliquely outwards. Strong chelipeds with well developed spines on the outer surface of carpus and on the anterior and posterior dorsal parts of propodus. Carapace green to almost black with legs that may be marbled. Geographical Distribution Indo-West Pacific: From East and South Africa to southeast and east Asia (from SE of China and Sri Lanka), and Northeast Australia. Also eastern around the Marianas, Fidji and Samoa Islands. Introduced in the Hawaii Archipielago. Habitat and Biology In soft muddy bottoms where it dig deep burrows. Migrations offshore (up to 50 km) to spawn. Diet based on molluscs (bivalves: Mytilidae, gastropods) and crustaceans (grapsid crabs), rarelly on plant material and fish. Adults remain buried at day, emerging at sunset and night to feed. Size Maximum carapace width: males between 25 to 28 cm (maximum weight between 2 and 3 kg). Interest to Fisheries Total production for Scylla serrata. Total capture for Scylla serrata. Collected mainly by trawling, and using traps, baited wire mesh pots, hooking and by hand. From 1990 to 1995 yearly catches for Scylla serrata from the Western Central Pacific ranged from 5 960 to 12 882 t (FAO yearbook of fishery statistics). These catches include, however, the 4 species of Scylla recognized (see remarks). Therefore, Scylla olivacea is probably the most common species in many markets of Southeast Asia. In Australia the fishery for S. serrata and S. olivacea reached 700 t collected between 1989 to 1990. The existing catch and management practices, currently applied to a single species ( S. serrata), have to be revised. The total catch reported for this species to FAO for 1999 was 13 431 t. The countries with the largest catches were Indonesia (8 560 t) and Thailand (3 050 t). The species is marketed alive. Some attempts to culture this species have been made. Literature Reference Carpenter, K.E. and V.H. Niem (eds.). 1998. F.A.O. species identification guide for fishery purposes. The living marine resources of the Western Central Pacific. vol. 2: cephalopods, crustaceans, holothuroideans and sharks. Rome. Hill, B.J. 1976. Natural food, foregut clearance-rate and activity of the crab Scylla serrata. Marine Biology. 34: 109-116. Keenan, C.P., P.J.F. Davie, and D.L.Mann. 1998. A revision of the genus Scylla De Haan (Crustacea: Decapoda: Portunidae). Raffles Bulletin of Zoology. 46(1): 217-245. Sakai, T. 1976. Crabs of Japan and the adjacent seas. Kodansha Ltd. Tokyo. 773 p. Vera, J.- 1992. Diccionario multilingüe de especies marinas para el mundo hispano. Ministerio de Agricultura, Pesca y Alimentación. Secretaria General Técnica. 1282 pp. Remarks In the same area coexist 4 Scylla species (including S. serrata) which taxonomy is still very confused (Keenan et al ., 1998). The other 3 species prefer mangroves and continental shelf habitats with less saline waters. 2 of this species - S. olivacea (Herbst, 1796), and S. tranquebarica (Fabricius, 1798)- are smaller than S. serrata (maximum cw for S. olivacea males: 18 cm). S. olivacea is brownish to browinish green in colour, sometimes orangish (Orange mud crab). Its carapace has very low transverse ridges, only a shallow H-shaped gastric groove, the median pair of frontal lobes are projected slightly forwards of the lateral ones and chelipeds have very low spines. S. tranquebarica is brown to almost black, having very well-developed spines on chelipeds as the case of S. serrata, differing from this species, however, by size and by having the frontal teeth more acutely triangular with the median pair projecting slightly frowards of the lateral ones. Finally the fourth species, S. paramamosain Estampador, 1949, are more related to rocky and near reefs habitats with intermediate characters to those cited for S. serrata and S. olivacea. Source of Information D.Lloris, Recursos Marinos Renovables, ICM.