Chinese Mitten Crabs Invade Md. Waterways

EDGEWATER, Md. (WJZ)—Whether you’re a commercial waterman or catch crabs off a dock, scientists at the Smithsonian want your help. Researchers know a foreign invader called the mitten crab is here.

Alex DeMetrick reports that the worry is how fast they’re reproducing.

There are all kinds of ways to catch crabs. But over the past few years, odd ones have been turning up.

“And we dragged out the pot, and we looked at it and thought it was mud on the claws. And then we seen it was fur; it was fur on them,” said Vince Meyer, waterman.

It was a Chinese mitten crab, and it was sent to the Smithsonian’s Environmental Research Center south of Annapolis. Finding them is critical, before they reproduce.

“We’re hoping they won’t, but there is the potential for the population to get quite large,” said Monaca Noble, Smithsonian Environmental Research Center.

“The introduction of a new species as prolific as the mitten crab could be pretty ugly,” said Jonathan McKnight, DNR biologist. “In places where the creatures have gotten loose before, they’ve clogged intakes, they’ve increased erosion in fresh water streams where they’ve dug into the banks.”

The first mitten crab was found near Baltimore in 2005, and it likely arrived as a stowaway hidden in the ballast water of ships.

Since then, the Smithsonian has received 200 more reports of mitten crabs from the Chesapeake to Hudson Bay.

And unlike native blue crabs, mittens spend most of their lives in fresh water.

If one is caught…

“I guess the most important thing is they shouldn’t throw it back alive,” Noble said. “They should take it.  I’d like them to photograph it and go online where they caught it and when.”

The Smithsonian has set up a special web center to track the invaders and their numbers.

“In places where there’s a lot of mitten crabs and there’s competition for space, like in China, they can travel as much as 1,000 miles upstream,” Noble said.

To report mitten crabs, click here.

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