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Chinese Mitten Crab

Eriocheir sinensis

The shell of the Chinese mitten crab can reach a width of up to 10 centimeters. (Smithsonian Environmental Research Center)
The shell of the Chinese mitten crab can reach a width of up to 10 centimeters. (Smithsonian Environmental Research Center)

The Chinese mitten crab is a light brown crustacean with a distinct pair of hairy, white-tipped claws. Native to East Asia, the invasive species has been reported in small numbers in the Chesapeake Bay.


  • Light brown, square-shaped carapace (shell) can reach width of up to 10 centimeters and features four lateral spines
  • Hairy, white-tipped claws resemble mittens
  • Distinctive notch is located between eyes
  • Legs are twice as long as width of shell
  • Males have a V-shaped abdomen, while females have a U-shaped abdomen


  • The catadromous species inhabits brackish and freshwater rivers and estuaries, but migrates into saltwater environments to reproduce
  • The Chinese mitten crab is the only crab found in the fresh waters of North America


  • Native to East Asia, where it can be found on coasts from Japan to the mainland of China, the Korean Peninsula and along the Yellow Sea
  • Also found on the coasts of northern and eastern Europe and the United States, and has been reported in small numbers in the Chesapeake Bay


  • Omnivorous, feeding on aquatic plants, algae, detritus, fish eggs and marine invertebrates


  • Common predators include fish, frogs and birds

Reproduction and Life Cycle:

  • The catadromous species migrates into saltwater environments in order to reproduce, with males arriving to mating territories first
  • Females lay between 250,000 and 1 million eggs that adhere to part of her abdomen. Over the winter, females remain under deep water as eggs develop
  • Once eggs hatch, larvae (called zoea) spend one to two months in brackish water before migrating upstream to develop into adults

Other Facts:

  • The Chinese mitten crab is a traditional food source in China, where it supports a large aquaculture industry.
  • Chinese mitten crabs can tolerate a wide range of environmental conditions and, when introduced to a new environment, can spread wide and fast. The effects of mitten crabs on the East Coast are not yet known, because their invasion is a recent one. The first confirmed sighting of a mitten crab in the region occurred in 2005, when a specimen was caught by a commercial waterman in the Maryland portion of the Chesapeake Bay.
  • The Maryland Department of Natural Resources (DNR), the Smithsonian Environmental Research Center (SERC), the U.S. Fish and Wildlife Service (USFWS) and the National Oceanic and Atmospheric Administration (NOAA) have established a Chinese Mitten Crab Watch to investigate the status of this invasive species.

Sources and Additional Information:

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