Washington's Coast
Washington State Department of Ecology

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The European green crab has invaded Washington's coastal bays and estuaries and could threaten shellfish.
What is the green crab?
The European green crab, Carcinus maenas, is a non-native predator that feeds on shellfish. Native to Europe, the green crab is considered an aquatic nuisance species in the United States.
 
Crab concerns
There is concern that the range of this crab could expand quickly -- affecting both shellfish and Dungeness crab. The green crab is a voracious predator. Growing numbers of green crab could seriously harm native ecosystems and shellfish aquaculture. Over 850 adult European green crabs have been discovered in Willapa Bay and over 250 in Grays Harbor.
How did they arrive?
Studies suggest that green crab larvae could have arrived in Oregon, Washington and British Columbia by strong ocean currents produced by the large El Niño event of 1997/98. Currents may have carried European green crab larvae into Willapa Bay and Grays Harbor. Green crab may have also arrived by ship, on ship hulls or through ballast water exchange.
 
What can be done?
The current goal is early monitoring and eradication before populations get out of control. The Washington Department of Fish and Wildlife is training citizens to monitor for the invasive green crab. Biologists are also conducting surveys.
The color of the green crab can range from dark green to orange and red with yellow patches.

European green crabs captured in Willapa Bay in 1998 were caught in intertidal areas dominated by Spartina alterniflora.
Images courtesy of: King County Department of Natural Resources and Parks.

European Green Crab, Aquatic Invasive Species, Washington Dept of Fish and Wildlife Life history, invasion, control, and coastal program.

European Green Crab Species Profile, National Invasive Species Information Center


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