Office of Public Affairs

USM alumnae, professor lead effort to eradicate invasive green crabs

green crab molting

Maine is under assault by the European green crab, an invasive species that feeds on clam beds and has been linked to the decline of the soft-shell clam industry. And with climate change a daily threat, populations of the crabs continue to rise in Maine and New England.

In fact, the value of last year’s harvest soft-shell clams — which Maine produces more than any other state — dipped nearly $4 million, the lowest harvest of soft-shell clams in Maine in decades, largely attributed to green crabs.

While much research has focused on the potential impact of the green crab invasion, research done at the University of Southern Maine (USM) is focusing its efforts on eradicating the species before it’s too late.

In an exclusive partnership with Manomet, an environmental research organization, USM students are working on this crisis exploring the connections between marine biology, industry and aquaculture.

Erica Ferelli, a recent graduate of USM and intern at Manomet, is working with fellow alumnus Marissa McMahan, senior fisheries specialist at Manomet, to spearhead the development of a commercial green crab fishery in Maine.

The goal: save one industry and bolster another by removing the invasive species from the environment while developing a culinary market for them.

It’s just one example of many ways USM is working with community and corporate partners to get students out of the classroom and into their fields of interest while solving real-world problems close to home.
green crab tempura at The Brunswick Inn“We want to find a way to mitigate the harmful impacts of that invasive species, and one of the ways to do that is develop a fishery,” McMahan said in an appearance on “The USM Update,” USM’s monthly cable access show, in April. “It’s not a wild, radical idea because there are culinary green crab products that exist in other countries that are worth a lot of money. It’s very lucrative.”

So lucrative are green crabs, McMahan told NECN, NewsCenter Maine and NBC Boston on Wednesday, some Maine fishermen have sold them to local restaurants for $3 for each small crab or about $20 per pound. In Brunswick — where Manomet has a satellite office — Brunswick Inn Executive Chef Ali Waks has been experimenting with green crabs. She’s made green crab dip, bouillabaisse, broth and even tempura green crabs.

"There's so much flavor there," Waks told reporter Danielle Waugh.

Community-Engaged Coursework

Erica Ferelli’s ongoing experience began last fall when, in class with Assistant Professor of Biology Rachel Lasley-Rasher, she and her classmates ventured to Kettle Cove in Cape Elizabeth to examine and measure the crabs which, when their shells are soft, are harvested.

In her ongoing internship, Ferrelli is analyzing data and monitoring green crab populations. This summer she has worked alongside McMahan gaining valuable, hands-on experience with field science, marketing and industry.

She said that hands-on experience primed her for a career after graduation.

“It makes everything applicable that I’ve learned in class,” she said. “There’s definitely a connection.”

Erica Ferelli measuring green crabLasley-Rasher said it’s a goal of hers to get students out of the classroom and into the field, in order to address real-world problems.

“There are so many organizations in Casco Bay that are doing interesting work in marine science and marine ecology,” Lasley-Rasher said. “I really wanted my students to get out and collect data that matters.”

That hands-on work, she said, is what separates USM students apart from the rest when it comes to starting their careers.

“I think it’s becoming appreciated more and more that internships are so important, if not essential, to getting a job after graduation,” Lasley-Rasher said. “What I want is for the students to just have an experience where they get a flavor for what a job in that field could offer.”

Those who have had prior experience in the field, McMahan said, are ideal candidates.

“When I’m looking for potential research technicians, I want to see that they’ve had hands-on experience,” she said. “We want to see that people can hit the ground running.”


By Alan Bennett / Office of Public Affairs

Research photos courtesy Marissa McMahan

Restaurant photo courtesy Danielle Waugh