Blue swimmer crab (sand crab)

This is a regulated species. See the size, take and possession limits for tidal waters.

  • Drawing of a blue swimmer crab, showing the underside of the male and the female
    Drawing of a blue swimmer crab, showing the underside of the male and the female
Scientific name

Portunus armatus (pelagicus)

  • grows to 22 cm in carapace width, and over 1 kg
  • growth occurs through the process of moulting - this involves the shedding of the hard exoskeleton and the swelling of soft body tissues to expand the new soft shell before it becomes calcified and hard
  • common size of crabs varies between populations
  • males are blue or purple with pearly white mottling
  • female crabs are much less colourful, being drab brown with pale mottling
  • females are much smaller than males
  • there are nine sharp spines on the carapace and the tips of the last pair of legs are disc-shaped for swimming
  • the carapace has a prominent projection on each side and claws are long and slender
  • the main predators on adult crabs are turtles, sharks, rays and large fish
  • a wide variety of fish and other crustaceans are likely predators on small juveniles
  • inhabit coastal waters from Cape Naturaliste in Western Australia, around the north of Australia to the south coast of New South Wales
  • marine coastal animals, occurring in bays, estuaries and intertidal areas to depths of 60 m
  • prefer muddy or sandy bottoms but can also be found on rubble, seagrass and seaweed
  • at dawn and dusk they feed vigorously on shellfish, other crustaceans, worms and brittle-stars on the sea floor
Size and possession limits
  • minimum size - 11.5cm
  • possession limit - no limit
  • female blue swimmer crabs are protected throughout Queensland and are therefore prohibited from being in anyone's possession without a permit.

Further information

Last updated 30 October 2012