MediaPress Release

Third Chinese Mitten Crab Confirmed in Chesapeake Bay

May 17, 2007

A third Chinese Mitten Crab has been found in the Chesapeake Bay. At about 9:30 am today, a waterman fishing off ofChesapeake Beach in northern Calvert County hauled in the third confirmed Chinese Mitten Crab found in Chesapeake Bay waters.

A native of Asia, the Chinese Mitten crab does not belong in the Chesapeake Bay but it could become a potentially harmful invasive species if established here. Invasion by mitten crab in Europe and on the West Coast of the U.S. has caused economic and ecological damage by clogging equipment and burrowing into embankments.

The first two confirmed specimens were caught in the Patapsco River near Baltimore Harbor, and identified last July by scientists from the Smithsonian Institution. One of the crabs had been captured a year earlier in 2005 and kept frozen until the Maryland Department of Natural Resources and the Smithsonian announced that they were on the lookout for this type of crab. With two large claws covered in setae that give the crab the appearance of wearing mittens, they are easily distinguished from other crabs found in the Bay.

Today’s mitten crab was captured off of Holland Point Bar in Chesapeake Beach, Maryland, 40 miles south of the location where the first two confirmed crabs were found. Greg Ruiz, a marine biologist who runs the Invasive Species laboratory at the Smithsonian Environmental Research Center noted that this represents the third confirmed crab captured in a three-year time span.  “We can’t say whether they are established [in the Bay],” he said, “but we can say that they are arriving to the system, and our earlier work has shown that the Chesapeake Bay is a place they could establish.”

Ruiz said that mitten crabs are also being fouvvnd in the Great Lakes, indicating that the crabs are finding their way to the Eastern United States, possibly in the ballast water of commercial ships coming from Europe where the invader is already present.

Young Mitten crabs spend two to five years in freshwater tributaries and can extend over 50 miles inland, potentially above fall lines. Mature male and female crabs migrate downstream to mate and spawn in salt water estuaries. Ruiz said he can’t predict the impact of the Chinese Mitten crab in the Chesapeake at this point because it is uncertain how it will interact with the organisms and conditions in the Bay ecosystem.  

The public is being asked to be on alert for Chinese Mitten Crabs in the Chesapeake Bay watershed. Identfying photos can be seen on our website at:

Anyone finding a mitten crab, please note the location it was caught, keep the crab on ice, and e-mail us at

Photos can be obtained from SERC’s FTP site at:

Navigate to the folder titled “Cutlip” there are six photos of the crab and the watermen who caught it.

Names and contacts for the watermen who caught the crab:

Vince Meyer, boat captain: 410-365-2612

Henry DuPreez: 410-282-1989

For more information about the Mitten Crab please see the following links: View the listing for Mitten Crab in the SERC NEMESIS database. National Exotic Marine and Estuarine Species Information System (NEMESIS) is a resource for information on non-native, or exotic, species that occur in coastal marine waters of the United States.

First records of Eriocheir sinensisH. Milne Edwards, 1853 (Crustacea, Brachyura: Varunidae) for Chesapeake Bay and the mid-Alantic coast of North America.  See the research article published in the journal  Aquatic Invasions on the Mitten Crabs found in the Chesapeake Bay.