Decapods crustacean form a major component of commercial fisheries in the Indo-Pacific region. The crab fishery is dominated by a few members of a single family, the Portunidae. They include four species of mud crab (genus Scylla De Haan, 1833), the blue swimming crab [Portunus pelagicus (Linnaeus, 1758)] and the gazami crab [P. trituberculatus (Miers, 1876)] (Lai et al., 2010).