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
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.