August 4, 2006

Annapolis, Maryland — The Maryland Department of Natural Resources (DNR) today announced that a mature male Chinese mitten crab (Eriocheir sinensis) was collected at the mouth of the Patapsco River by a commercial waterman fishing crab pots. The species is native to East Asia, and is a potential invasive that could have negative ecological impacts.
The Chinese mitten crab can live in both freshwater and saltwater. It is catadromous, meaning it migrates from freshwater rivers and tributaries to reproduce in salt water. Young crabs spend 2-5 years in freshwater tributaries and can extend over 50 miles inland, potentially above dams and waterfalls. The Chinese mitten crab is listed under the Federal Lacey Act, which makes it illegal in the United States to import, export, or conduct interstate commerce of this species without a permit.

“This is the first confirmed recorded case for the Chesapeake Bay,” said Lynn Fegley, a fisheries biologist with DNR. “Only a single animal has been captured in the Chesapeake Bay, and at this point it appears to be an isolated occurrence. As with all invasive species, DNR and its partners are carefully monitoring the situation.”

There are several possible transfer mechanisms that could result in the delivery of a crab to local waters, without the species becoming established. However, due to the documented ability of this species to invade and establish itself in new areas, DNR, the Smithsonian Environmental Research Center (SERC), and USFWS have established a joint effort to investigate the status of this species.

“This is the most recent non-native species to arrive to the Chesapeake,” said Dr. Gregory Ruiz, a marine invasive species specialist with the Smithsonian Environmental Research Center. “Our research documents over 150 non-native species that are now established in tidal waters of the Bay, and the rate of invasions appears to have increased in the past few decades due to human-mediated transfer. Detection of the mitten crab contributes to understanding of this broader invasion pattern and how these species are moved.”

An alert has been circulated to federal, state, county, municipal and private agencies as well as organizations that are conducting sampling programs in the Chesapeake watershed and potential mitten crab habitat. DNR is also networking with commercial watermen, fish passage monitoring programs, and power companies that monitor species captured on cooling water intake screens to keep a watch for this species.

“I would urge anyone who many come in contact with one to keep the crab, take a photo of it, note the location of discovery, and contact me at 410-260-8285,” added Fegley.

The collected mitten crab is currently located at SERC and is being studied to potentially identify its source. The crab will be preserved at the Smithsonian’s National Museum of Natural History, where it will be catalogued and entered into the permanent national collection.

For more information on the mitten crab as well as to access links to other websites, visit

www.dnr.maryland.gov/dnrnews/infocus/mitten_crab.asp or
www.serc.si.edu/labs/marine_invasions/news/mitten_crab.jsp