Part 1 – Biology
9
Table 1.3
The percentage contribution of claws to total body weight of male and female Scylla serrata at different ontogenetic phases Total weight of crab (g)
% weight contributed by claws – male
% weight contributed by claws – female
1.0
21
21
165
26
–
668
40
22
2 193
50
20
Source: Heasman, 1980.
In mud crabs, food location is reported to be by contact chemoreception using the dactyls of their walking legs. The anatomy of mud crab legs is typical of the family Portunidae, with the fifth pair of walking legs flattened into paddle-like structures that are used in swimming. Mud crabs have the ability to release legs or claws if handled roughly (autotomy) and can regenerate these limbs; however, it usually takes two or more moults for the regenerated limbs to regain the same size as limbs that have not been subject to autotomy. REFERENCES Fielder, D.F. & Heasman, M.P. 1978. The mud crab. A Queensland Museum Booklet, 15 pp. Heasman, M.P. 1980. Aspects of the general biology and fishery of the mud crab Scylla serrata (Forskal) in Moreton Bay, Queensland. University of Queensland. (Thesis). Keenan, C.P., Davie, P.J.F. & Mann, D.L. 1998. A revision of the genus Scylla de Haan, 1833 (Crustacea: Decapoda: Brachyura: Portunidae). Raffles B. Zool., 46(1): 217–245. La Sara, Aguilar, R.O., Laureta, L.V., Baldevarona, R.B. & Ingles, J.A. 2007. The natural diet of the mud crab (Scylla serrata) in Lawele bay, Southeast Sulawesi, Indonesia. Philipp. Agri. Sci., 90(1): 6–14. FURTHER READING Akil, J.M. & Jiddawi, N.S. 1999. Reproductive migration in the mangrove crab Scylla serrata in Zanzibar. Conference on advances on marine sciences in Tanzania, 1999 of Conference. 11. Anon. 2006. Australian Prawn Farming Manual. Health management for profit. The State of Queensland, Department of Primary Industries and Fisheries, 157 pp. Arriola, F.J. 1940. A preliminary study of the life history of Scylla serrata (Forskal). Philipp. J. Sci., 73: 437–454. Ashton, E.C., Macintosh, D.J. & Hogarth, P.J. 2003. A baseline study of the diversity and community ecology of crab and molluscan macrofauna in the Sematan mangrove forest, Sarawak, Malaysia. J. Trop. Ecol., 19(2): 127–142. Barnes, D.K.A., Dulvy, N.K., Priestley, S.H., Darwall, W.R.T., Choisel, V. & Whittington, M. 2002. Fishery characteristics and abundance estimates of the mangrove crab Scylla serrata in southern Tanzania and northern Mozambique. S. Afr. J. Mar. Sci./S.Afr. Tydskr. Seewet., 24: 19–25. Becker, K. & Wahl, M. 1996. Behaviour patterns as natural antifouling mechanisms of tropical marine crabs. J. Exp. Mar. Biol. Ecol., 203(2): 245–258. Bellwood, O. 2002. The occurrence, mechanics and significance of burying behaviour in crabs (Crustacea: Brachyura). J. Nat. Hist., 36(10): 1223–1238. Bonine, K.M., Bjorkstedt, E.P., Ewel, K.C. & Palik, M. 2008. Population characteristics of the mangrove crab Scylla serrata (Decapoda: Portunidae) in Kosrae, Federated States of Micronesia: Effects of harvest and implications for management. Pac. Sci., 62(1): 1–19. Brown, I.W. 1993. Mangrove Crabs. In A. Wright & L. Hill, eds. Nearshore marine resources of the South Pacific, pp. 609–642. Suva Institute of Pacific Studies. Chandrasekaran, V.S. & Natarajan, R. 1994. Seasonal abundance and distribution of