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Striped Shore Crab or the Lined Shore Crab

Pachygrapsus crassipes

Abundant in crevices, tide pools, and mussel beds, and sometimes on muddy shores of bays and estuaries, this crab lives between Charleston, Oregon to Baja California (and can also be found in the Gulf of California, Japan, and Korea.). It is native to the west coast of North America, as it was not reported in Asia until 1890.

With a squarish carapace (main body shell) up to two inches (48mm.) wide, the shore crab is marked with shades of red, purple, or green. It is well adapted to semi-terrestrial life, spending at least half its time out of water. Its main food, is the film of algae and diatoms growing on the rocks in higher pools and crevices, which the crab scrapes off with its claws. Shore crabs also eat dead animals they find. Living prey are comprised of limpets, snails, crabs, and even the unwary fly: a quick lunge can result in a successful catch.

In turn, these crabs are eaten by sea gulls, rats, raccoons, and even man. Mating occurs after the female molts, while she is still soft-shelled, the male rolls over on his back and the female walks above him. Older crabs are sometimes seen encrusted with bryozoans and barnacles, suggesting that they may have ceased to molt. If you're interested in crabs, you might want to take a look at Purple Shore Crab.

Last modified: June 10, 1997 by Marti
Comments, complaints, compliments -- marti@cse.ucsc.edu