We seek your help to determine the current distribution status of the mitten crab in the region. Please report any mitten crab sightings to us, along with details (date, specific location, size) and a close-up photograph or specimen if possible. Specimens are best frozen or kept on ice. Your report of new sightings is vital to understanding and possibly preventing the spread of this crab. The first confirmed record along the entire eastern United States, from Florida to Maine, was in the Chesapeake Bay near Baltimore, Maryland in 2005. This initial crab was reported by a commercial crabber. Many additional crabs have been confirmed since this time and nearly all have been reported by commercial and recreational fishermen.
The Chinese Mitten Crab (Eriocheir sinensis) is native to East Asia and is an established invader in Europe and the United States. The first established US population was in California’s San Francisco Bay and Delta (1980s). This crab has also been found in the Great Lakes and the US Gulf Coast, but it does not appear to have a breeding population in either region. Since 2005, over 100 mitten crabs have been found in estuaries along the US mid-Atlantic, from Maryland to New York, and its potential range includes coastal waters from Virginia to Texas.
Mitten crabs occur in both freshwater and saltwater environments. Adults migrate from freshwater to estuaries to breed. Their larvae develop in marine environments until they become juvenile crabs, at which time they migrate into freshwater tributaries. Adults spend between two and five years in the freshwater tributaries before returning to the estuaries to breed.
This crab can have negative ecological and economical impacts and 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 without a permit.
The Smithsonian Environmental Research Center, working with many partner organizations, has established Mitten Crab Watch as a public reporting and information network to track the distribution, abundance, and status of this species for the US Atlantic and Gulf coasts.
Please report any mitten crab sightings along with key details, as outlined below.
If you catch a mitten crab