Dungeness Crab    Cancer magister

Trying to hide under some giant plumose anemones at the Boston Harbor Marina in mid May, a pair of dungeness crabs are locked in a mating embrace.  The larger male (about 9 inches) holds the female for several days until she molts her hard shell.  At that point mating occurs and she wanders off with the stored sperm.  Fertilization occurs when eggs are released in late fall or early winter. The eggs are held under the broad tail for several months until hatching.  The young then become planktonic, drifting for four months and finally settling to the bottom to mature.  

Dungeness crab can be distinguished from the similar appearing graceful crab by their larger size (males growing to 8 to 10 inches wide, females to 6 inches), the large tooth at the widest point of the shell margin and the lack of white edging of the carapace teeth.  Their large claws are white-tipped unlike the red rock crab which has black-tipped claws and a red shell.

They prefer a sandy-mud bottom or eelgrass beds from the low intertidal to the subtidal (to a minus 700 ft). There they can be found hiding in the sediment or actively hunting shrimp, fish, clams, worms and oysters.  Predators include gulls, dog fish, wolf eels, large sculpins and octopus.  The average life span is around 6 years.

A commercial and recreational species both in Puget Sound and off the coast, the dungeness crab occurs from the Aleutian Islands of Alaska to southern California.  Contact the Washington Department of Fish and Wildlife at http://wdfw.wa.gov/ for harvest information.