Invertebrates
Common Shore Crab
Carcinus maenas · also called green crab
In a rock pool at low tide, a common shore crab scuttles sideways under a frond of seaweed, one of the most abundant and adaptable crabs on European shores.
Overview
The common shore crab, Carcinus maenas, is a Not Evaluated crab of rock pools, saltmarshes, and estuaries in the northeast Atlantic and the Baltic. Its toughness and its spread to other continents make it one of the most successful, and one of the most unwelcome, crabs in the world.
A crab that conquered the world
Carried in ships and with shellfish, the shore crab has settled on the coasts of North America, South Africa, Australia, and Japan, where it competes with native animals.
Status
Not Evaluated globally, abundant at home and invasive elsewhere.
Common Shore Crab: common questions
Why is the common shore crab called the green crab?
It is often called the green crab in North America, for its greenish-brown shell.
Why is the shore crab a problem outside Europe?
It harms native shellfish and eelgrass beds in places where it has been introduced, including North America, South Africa, Australia, and Japan.
How does it spread?
Its larvae drift in the plankton for weeks, and adults and larvae are carried in ships and with shellfish.
Where is the common shore crab native?
It is native to rock pools, saltmarshes, and estuaries on the coasts of the northeast Atlantic and the Baltic.