If You Can’t Beat ‘Em, Eat ‘Em!

Scientists and chefs team up to bring invasive green crabs under control

When species leave their native habitats, they can wreak havoc on new ones. But there are ways to stop them. One way is to eat them.

What’s at stake

Invasive green crabs are destroying clam and mussel populations in New England waters at an alarming rate. These crabs, brought from Europe in the age of sail, are thriving as the water temperature rises. They have even turned up San Francisco Bay and the coast of Washington state. One adult green crab can eat over 60 juvenile soft-shell clams in a single day. They also threaten lobster populations in Maine, where they eat baby lobsters and compete with them for food.

A culinary market for green crabs

Green crabs aren’t just invasive and plentiful; they’re also delicious. If green crabs became a restaurant staple, it would control their numbers, and restaurants and foodies would benefit.

  • NOAA funded the Maine/Massachusetts nonprofit Manomet to grow demand for a green crab fishing industry. Manomet started by working with chefs, underwriting Green Crab Week. Manomet supplied the crabs to several New England restaurants for their nightly menus. Dishes like Green Crab Roe & Leek Croquettes resulted.

  • In another science-culinary joint venture, a fisheries specialist at Sea Grant New Hampshire worked with the Portsmouth, NH restaurant Moxy. Diners loved Moxy’s dishes, such as green crab stew with chicken sausage and chili oil. Green crabs are easier to eat in their soft-shell stage. But they make a wonderfully rich broth even when their shells are hard. This broth can be used in soups, stews, risotto, and paella. See this story by Elizabeth Dinan.

  • A cookbook published in 2019 promotes green crab recipes for the North American market. The authors drew on recipes from places where green crabs are native, like Venice, Italy. Venetians eat green crabs in several forms, including caviar. See this story by Chris Chase on the cookbook’s release.

  • Green crabs are good for you! A 2020 study found that they contain a compound that helps control blood sugar. See the study in the journal Foods.

Control green crabs by eating them? Their parents will help.

Restaurants aren’t the only ones with culinary designs on young green crabs; adult green crabs are cannibals. When scientists testing population-control left just enough adults to eat some of the hatchlings, the green crab population plunged by 86 percent, compared with removing all the adults. Understanding an invasive species is the first step in being able to manage it. See this story by Peter Arcuni.

Dogs like them, too

The University of Maine’s Sustainable Ecological Aquaculture Network (SEANET) made dog biscuits from green crabs and found that dogs loved the treats. If this moves from research into production, it could help reduce green crab populations while creating economic opportunity. See this University of Maine press release.

Use them for bait

Entrepreneurs in New England have already found ways to turn the green crab problem into a business opportunity. Chatham, Massachusetts-based Green Crab Nation started selling green crabs as bait about four years ago. They’re less expensive than horseshoe crabs, and they’re certainly plentiful. See this story by Emily Canal in Inc.

Catching crabs

If you’re going to eat them, you have to be able to catch them. Scientists are studying the best type of bait to use to catch green crabs. Traps baited with squid and cod captured more green crabs than traps baited with herring. See the original study in the journal Fisheries Research.

Fewer crabs, less plastic waste

Food isn’t the only way to consume green crabs. In Canada, a chemistry professor at McGill University has found a way to turn green crab shells into biodegradable plastic using a non-toxic process. The plastic could be used to make cutlery, cups, and plates. See this story by Emma Smith in CBC News.