Invasive Chinese Mitten Crab
In the Hudson River Estuary
Photo by Tom Lake, Estuary Naturalist
Chinese mitten crabs (Eriocheir sinensis) are aquatic invaders in the Hudson River. They are native to East Asia and have been a costly and environmentally damaging invader in Europe and San Francisco Bay. While we are not certain how the crab arrived in New York, it is most likely that it occurred through live release or transport in ship ballast water.
DEC is asking concerned citizens, crabbers, and anglers to keep a look out for this species and let us know if you think you have caught one.
Habitat and Current Known Locations
These crabs may be found in both freshwater and salt water. They are walking crabs that can emerge from the water to move upstream of barriers and are capable of moving several hundred miles upstream from saltwater. They spend most of their lives in freshwater rivers, migrating to brackish or salt water to reproduce. The young move upstream, sometimes spending 2 - 5 years in freshwater.
The first mitten crab found in New York was caught in early June 2007 in the Hudson River near Tappan Zee and the crabs have since moved upriver. The discovery of juvenile crabs indicated that the mitten crabs were reproducing in the river. Since 2014 the number of sightings in the Hudson River has dropped significantly. In May 2018 a crabber caught a mitten crab near Yonkers.
Chinese mitten crabs have been reported along the East Coast in Chesapeake Bay and Delaware Bay and the West Coast in San Francisco Bay. Reports have also been made for the Eastern Great Lakes, but there is no evidence that populations are established and reproducing there (USGS Nonindigenous Aquatic Species map) (link leaves DEC website).
Environmental Impact
These crabs are aggressive and may compete with our popular native blue crab in the Hudson River. Their burrowing habits may threaten stream bank and earthen dam stability and promote erosion and habitat loss.
Identification
- Only freshwater crab in the Hudson River drainage
- Claws equal size with white tips and hair
- Carapace (shell) up to 4 inches wide; light brown to olive color
- Eight sharp pointed walking legs; no swimming legs
What To Do If You Catch a Chinese Mitten Crab
- Do not release it back to the water.
- Keep it and freeze it (preserve in alcohol if you can't freeze it).
- Note date and location caught (GPS coordinates preferred but pinpointed on a map is acceptable) and how you caught it.
- If possible, take a close-up photo. Please make a report within 48 hours of catch that includes photos and location information to isinfo@dec.ny.gov or 518-402-9425.
DEC and Partner Efforts
DEC is a partner in the Mitten Crab Network, a partnership among several state, federal and research organizations that is collecting data to determine the status, abundance and distribution of this species. DEC has agreed to collect and hold specimens for genetic testing to determine the origin of individuals caught in the Hudson River. Testing will be conducted by the Smithsonian Environmental Research Center (SERC) where scientists are tracking the distribution and spread of Chinese mitten crab throughout North America (leaves DEC website). All confirmed reports of Chinese mitten crab will be added to the National Exotic Marine and Estuarine Species Information System (NEMESIS) (leaves DEC website).
NOTE: 6 NYCRR Part 575 Regulated and Prohibited Species includes Chinese mitten crab as a prohibited species in New York along with many other aquatic invasive species.
NYS Fish and Wildlife regulations (Section 44.10) prohibit releasing Chinese mitten crab into waters of New York State; prohibits possession, importation, transportation, purchase or sale or offer of purchase or sale of Chinese mitten crab whether dead or live. This regulation requires Chinese mitten crab to be destroyed unless lawfully held under a license or permit to collect, possess or sell for propagation, scientific or exhibition purposes issued under section 11-0515 of the Environmental Conservation Law. In addition, the Federal Lacey Act prohibits inter-state transport of Chinese mitten crabs.
