European Green Crab
What are they?
The European green crab is a small shore crab that is not necessarily green like its name implies. It typically is found in high intertidal areas and marshes in coastal estuaries and wave-protected embayments, and can live on a variety of surfaces including sand, mudflats, shells, cobble, algae, and rock. It is an opportunistic feeder and aggressive invader. It is native to the eastern Atlantic from Norway to North Africa.
Are they here yet?
Yes. Green crabs have been documented on the Pacific Coast of Washington, as well as on the southern tip of neighboring Vancouver Island, Canada.
Why should I care?
The European green crab eats smaller crustaceans and many other plants and animals, and can have dramatic negative impacts to native shore crab, clam, and oyster populations. Green crabs are believed to have caused the collapse of the soft-shell clam industry in New England; their digging habits also have slowed eelgrass restoration efforts. European green crabs also may impact the health of shore birds by transmitting the worm Profilicollis botulus.
What should I do if I find one?
Do not purchase, release, or trade this species. Report a sighting online.
How can we stop them?
Prevent the spread of green crabs by retaining any killed green crabs and reporting the find, as described above. The green crab is classified as a Prohibited Aquatic Animal Species in Washington, meaning it may not be possessed, purchased, sold, propagated, transported, or released into state waters (Revised Code of Washington 77.12.020, Washington Administrative Code 220-12-090).
What are their characteristics?
- Juveniles are speckled with green, black, white, and rust.
- Adults vary in color from reddish to dark green, and are often mottled olive-brown with black and yellow spots.
- Adults’ undersides may be green, pale orange, or red.
- The adult male’s carapace grows to 3-4 inches across.
How do I distinguish them from native species?
The green crab may be distinguished from native helmet or hairy shore crabs by five evenly spaced curved spines on each side of its shell, three rounded lobes between the eyes, and a somewhat flattened last pair of legs.