Box Crabs

BROWN BOX CRAB IS A type of king crab that usually habitats between Kodiak Island, Alaska, and San Diego, California. This crustacean’s descriptive name comes from its tendency to bury itself in the mud while pulling its legs in underneath its body and folding its claws in front of it – thereby appearing box-shaped.

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Physical Attributes

Box crabs have a heavily calcified carapace covered with sharp spines aids in its natural camouflage.The carapace grows up to 15 cm (6 in.) across, it is red-brown or tan in colour with white and purple patches. They have relatively short legs, and its fifth pair of legs are small and folded under the carapace, making it seem as if it only has four pairs of legs. While buried, two circular holes (foramins) in the claws allow for water circulation to the gills. The brown box crab's large claw (usually the right) has blunt white teeth, while the small claw has sharp teeth.


Box crabs lives in aggregations, moves together, and molts at similar times within the aggregation. They have a biennial (two year) breeding cycle, females molt and breed in mid-summer, brood eggs and larvae for 18 months, and release zoeae over 69 days during the second winter/early spring after breeding. It passes through four larval stages before becoming a juvenile and gaining the ability to walk.

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The box crab resides in depths of low intertidal to 600 m (1968 ft), but is usually found deeper than 18 m on muddy bottoms or on rocky faces over mud. It scoops up mud to feed on bivalves and organic debris, and also feeds on brittle stars and sea urchins. This crab is preyed upon by octopus, and may be parasitized by commensal organisms including snailfish, whose eggs and larvae can be found on crab gill filaments, and polychaete tubeworms, hydrozoans, and small bivalves on brooding and post-brooding females.


As established by the Marine Life Management Act, the California Fish and Game Commission (CFGC) regulates the fishery, and the California Department of Fish and Wildlife (CDFW) manages this fishery in state waters. Currently there is no established fishery management plan, but California Sea Grant, the Pacific States Marine Fisheries, the Ocean Protection Council, CDFW, and NOAA Fisheries are presently working with fishermen to collect information about this fishery.

Ways to manage fishery

  1. Encourage sustainable fisheries management.

  2. Fully implement the international plan of action for sharks.

  3. Support CITES management of sharks and rays.

  4. Reduce Illegal fishing through catch documentation.

  5. Follow through on recommendations in the recent review of the Fish Stocks Agreement.


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