Chinese Mitten Crab Alert

1 June 2007
Chesapeake Bay, Delaware Bay, and U.S. Atlantic Coast Bays

Please Report Sightings of this Crab

Mitten Crabs in the Eastern U.S. Live Chinese Mitten Crabs (Eriocheir sinensis) have been caught in crab pots in Chesapeake Bay (2005-2007) and Delaware Bay (May 2007). These are the first confirmed reports for the eastern United States. To date, there have been seven crabs documented, and five have been in the past two weeks. We don’t yet know whether the crab has established reproductive populations in these estuaries or spread to other locations along the eastern U.S.

The Chinese Mitten Crab is native to East Asia, and is a potential invasive that could have negative ecological impacts. Mitten Crabs are already established invaders in Europe and on the West Coast of the United States. The crab is listed as Injurious Wildlife under the Federal Lacey Act, which makes it illegal in the United States to import, export, or conduct interstate commerce of Mitten Crabs without a permit. Life History. The Chinese Mitten Crab occurs in both freshwater and salt water. It is catadromous, migrating from freshwater rivers and tributaries to reproduce in salt water. Young crabs spend 2-5 years in freshwater tributaries and can extend miles upstream of bays and estuaries. Mature male and female crabs migrate downstream to mate and spawn in saltwater estuaries. Chinese Mitten Crabs burrow into banks and levees along estuaries and are able to leave the water to walk around obstacles while migrating.

Please Report any New Sightings. To determine the status, abundance, and distribution of this species along the eastern U.S., we have established a Mitten Crab Network. The Network began as a partnership among several state, federal, and research organizations, with an initial focus on Chesapeake and Delaware Bays. We now are expanding the Network to include resources managers, commercial fisherman, research organizations, and citizens along the eastern U.S.

Please help by reporting any mitten crabs directly to the Network or to your state resource manager.

Identification

• Only crab in fresh waters of North America
• Claws equal in size with white tips and hair
• If you find a crab without hair on the claws, it is NOT likely to be a Mitten Crab
• Carapace up to 4 inches wide; light brown to olive green in color
• No swimming legs. This crab has eight sharp-tipped walking legs

If you catch a mitten crab

• Do not throw it back alive!
• Freeze the animal, keep it on ice, or preserve it in rubbing alcohol as a last resort
• Note the precise location and date where the animal was found
• Please take a close up photo of the animal. Photos can be emailed to SERCMittenCrab@si.edu for preliminary identification. Include your contact information with the photo
• If you cannot take a photo contact the Mitten Crab Hotline (443-482-2222)

REMEMBER THE LAW! Never transport a live Mitten crab across state boundaries.

For additional information please visit https://serc.si.edu/research/research-topics/biological-invasions for updated Mitten Crab reports, downloadable pamphlets on the Chinese Mitten Crab Survey Program, and how to distinguish a Mitten Crab from other crabs in the region.

For more information on the Chinese Mitten Crab Survey, go to the Smithsonian Environmental Research Center web site at http://www.serc.si.edu/.

Rhode Island contacts for sightings of the crab:

Kevin R. Cute, Marine Resources Specialist
Coastal Resources Management Council
Stedman Government Center
4808 Tower Hill Road
Wakefield, Rhode Island 02879
Phone: 401-783-3370
Fax: 401-783-2069
Email: kcute@crmc.ri.gov

Chris Deacutis, Chief Scientist
Narragansett Bay Estuary Program
PO Box 27
URI Bay Campus 02882
Phone: 401-874-6217
Fax: 401-874-6869
Email: deacutis@gso.uri.edu

David Gregg, Executive Director
RI Natural History Survey
PO Box 1858
Kingston, Rhode Island 02881
Phone: 401-874-5800
Fax: 401-874-5868
Email: dgregg@rinhs.org