UNH Scientists Hope Citizen Survey of Invasive Green Crabs Will Lead to Fishery

Apr 14, 2018

European green crabs arrived in ships' ballast water on Cape Cod in the 1800s and have since spread across New England's coastline.
Credit NH Seagrant

Scientists at UNH want the public’s help to search for invasive green crabs this spring and summer.

The second year of the monitoring project starts this Saturday.

New Hampshire Sea Grant biologist Gabby Bradt wants to find hotspots of green crabs, and determine when they molt, on the coast.

“And the reason for that is I'm really interested in figuring out when we can harvest soft shell crabs for a fishery and for a seafood market,” she says.

Bradt says New Hampshire is home to millions of the hardy invaders, which love to burrow into delicate eelgrass beds and eat other shellfish.

“That is a problem, especially if you have a soft shell clam industry or mussel industry or an oyster industry, because they can burrow, they can dig up all the shellfish and decimate those populations,” she says.

The crabs’ shells are normally too hard to crack. But as soft shells, Bradt says they’re great to eat in soups and sandwiches.

That’s why she hopes fishermen will want to trap them and cull their numbers – if they know where to look.

She plans to deploy citizen scientists to document the crabs under rocks and in seaweed on Seacoast beaches and in tide pools, one day a month from now until September.

The first survey begins at 2 p.m. Saturday at the Seacoast Science Center.