Chinese Mitten Crab

Photo credit: California Department of Fish and Game

What is it?

A burrowing crab with white-tipped, hairy-looking claws

Where's it from?

East Asia

How did it get here?

Unknown. It was possibly released accidentally in ship ballast water or deliberately to establish a fishery.

Where is it now?

Chinese mitten crab became established in the San Francisco Bay in the late 1980s, where it has continued to spread and cause a range of problems. In 2006, it was found in the Chesapeake Bay. Since then, a number of individuals have been found around the Bay, but evidence of the species being established has yet to be found.

What's the harm?

They foul fisheries by stealing bait from traps and fishing lines, clog power plant water intake pipes, cause stream bank collapse due to innumerable burrows, and alter aquatic ecosystems by competition with native species.

What's being done?

In the Chesapeake Bay region, efforts are underway to educate the public about the crab and enlist help in reporting any suspected discoveries.

How can I learn more?

Go here >>.