Chinese Mitten Crab (Eriocheir sinensis) — identification, habitat & look-alikes

The Chinese mitten crab is a crab from East Asia, named for the furry "mittens" on its claws. It has turned up in rivers and bays on both U.S. coasts and is regulated as a harmful invasive species. In its homeland it is a prized fall delicacy known as Shanghai hairy crab.

Appearance

Appearance: Light brown to green shell up to about 3 in (8 cm) wide, with a deep notch between the eyes and four sharp spines on each side. The claws are white-tipped and covered in dense brown hair. Young crabs under 1 in (2.5 cm) may lack the hairy patches.

Where it lives

Typical habitats: rivers
estuaries
Range: Native to East Asia, from Korea south to Fujian, China. In the U.S., it has been found in San Francisco Bay and the rivers upstream, though adults have become rare there since about 2012. On the East Coast it was first recorded in Chesapeake Bay in 2005 and the Hudson River in 2007, and two separate detections were made in Oregon in 2025.
Preferred conditions: Lives mostly in fresh water and moves down to to breed.

Behavior

Diet: Eats a wide range of food, including clams, mussels, and fish eggs.

Life cycle

Reproduction: Adults migrate downstream to brackish water to spawn. Larvae drift in salty water, then young crabs move back up into fresh water.
Lifespan: Breeds only once, near the end of its life, and wastes away afterward.

Cautions

Cautions: Can carry lung flukes that infect people who eat the crab raw or undercooked.

Conservation

Conservation: Listed as injurious wildlife under the federal Lacey Act, so importing it is tightly regulated. Washington lists it as a prohibited species. It is on the list of the world's 100 worst invasive species.
Threats: In the U.S. it competes with and eats native species, and its burrows can damage levees and riverbanks. Crabs can clog fish screens and pipes, and they steal bait and damage fishing nets.