GREENWICH, Conn. (WTNH) — Many Connecticut beaches, boat docks and marinas have been posting signs warning of invasive mitten crabs that officials say are growing in numbers in the state.
The crabs are originally from southeast Asia, but were first spotted along the East Coast of the U.S. in 2005. They were first seen along the Hudson River around 2008 and in Greenwich by 2012.
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According to the Department of Energy and Environmental Protection (DEEP), there were no freshwater crabs in North America until mitten crabs arrived.
“They’re kind of cool, they’re like large spiders,” DEEP Fisheries Biologist David Molnar said. “They will crawl right up you very quickly.”
Molnar believes the crabs may have arrived either through a ship’s ballast water or were brought from overseas as food. He said they are often found under rocks and debris, hiding during the day and coming out at night. The crabs are also known to travel several miles.
“To date we’ve captured 150 mitten crabs this year, and they’ve gone all the way to the Connecticut River,” Molnar said.
Molnar stressed that the crabs are currently at low abundance in Connecticut, mainly because they haven’t found a preferred habitat yet. Their numbers are not yet high enough in the state to cause damage, but DEEP is monitoring the situation closely and urging people to report sightings, kill the crabs and freeze them. The department is also warning against eating them for the time being.
Molnar said it’s unclear what ecological effects of the crabs will have, but said they’re moving eastward and have already become part of the area’s ecosystem and food chain. He said the Lacey Act prohibits the introduction of species that may cause harm.
“You’ve got to remember, these crabs have been on the planet a lot longer than us,” Molnar said. “So, they’ve evolved for specific habitats.”
More information on mitten crabs and their presence in North American can be found on the U.S. Geological Survey’s website.
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