Abstract
Portunus pelagicus Linnaeus is a bottom-feeding carnivore, eating a wide variety of sessile and slow moving invertebrates. Diet is largely dependent upon local availability of prey species: the main foods for intertidal P. pelagicus are small hermit crabs and gastropods and for subtidal P. pelagicus are bivalves and ophiuroids. Diet composition changes little with size of crab although within broad taxonomic groups e.g. the Gastropoda, prey species change with size of crab. Diet did not vary seasonally for juvenile P.pelagicus in intertidal areas.
Crabs cease feeding prior to and during moulting. Immediately after moulting, the gastric mill is filled with calcareous fragments. As the crab shell hardens, feeding on organic material commences, being greatest during the early intermoult period and reduced in later intermoult.