Photo courtesy Sylvia Yamada, Zoology Department, Oregon State University, Corvallis OR 97331

    Green crab is a small shore crab whose native distribution is along the coasts of the North and Baltic Seas. Although known by the common name of green crab, the shell (carapace) color can vary from dark, mottled green to orange or red, with yellow patches on the dorsal carapace. The crab is an able and effective forager and is capable of learning and improving upon its food-gathering skills. Studies have shown that the green crab is quicker and more dexterous than most crabs, and can open bivalve shells in more ways than other crabs. One adult crab reportedly can eat 40 half-inch clams each day and can devour crabs it own size. Green crabs also prey on numerous other organisms-making these crabs potential competitors for the food sources of native fish and bird species. The recent arrival of the green crab on the U.S. West Coast is cause for concern. The green crab is well known as a global invader having already invaded numerous coastal communities outside of its native range, including South Africa, Australia, and the east coast of North America. An able colonizer and efficient predator, this small shore crab has the potential to significantly alter any ecosystem it invades. It has been blamed for the collapse of the soft-shell clam industry in Maine. First seen in San Francisco Bay in 1989, the green crab has been moving northward to Humboldt Bay, California. Live specimens have been found recently in Coos Bay, Oregon and Willapa Bay, Washington, and on the west coast of Vancouver Island. Within the Inland Waters of Washington and British Columbia, there is concern that green crab invasion could put Dungeness crab, clam and oyster fisheries at risk.

See the Washington Department of Fish and Wildlife's green crab fact sheet for green crab pictures and additional green crab information: http://www.wa.gov/wdfw/fish/ans/greencrab.htm