YORK, Maine — In his days as a York High School marine science teacher, Mike Masi would educate his students about green crabs and other invasive species in the Gulf of Maine. Nowadays, Masi and a former student catch green crabs and sell them as food to high end restaurants and bait to commercial fishermen.

Masi, a diver, fisherman and member of the York Shellfish Commission, and Sam Sewall, an eighth-generation lobsterman and Masi’s old student, are the co-founders of York-based Shell + Claw, a business devoted to the study and commercial harvesting of green crabs. The two founded the business in 2020 and have sold green crabs for the last three years, putting in long hours of work to further their knowledge of the crustacean’s impact on local marine life.

The state refers to green crabs as Maine’s “most destructive and costly invader.” The species arrived to Maine shores in the mid-1800s in ballast water from European ships and soon began damaging soft-shell clams and the local marine habitat through their predation. 

One solution to help curb the crabs’ impact? Catch them, cook them and eat them, just as Shell + Claw’s co-founders do. Crabs caught in the York River are taken by Masi and Sewall, when they are molting, and sold to regional restaurants for their soft-shell crab meat while hard-shell green crabs can be purchased as bait.

“One of the things we’re really trying to do is diversify the options of working waterfront,” Masi said. “So many of our eggs are in the basket of lobster here in the state of Maine. It’s lobster or nothing in a lot of communities. So what happens if the lobsters continue moving offshore, continue moving more up the coast? What happens if regulations become too stringent? It could be a real hit to the working waterfront. Once you lose working waterfront, it’s not going to come back. Having diversity will add resiliency to the working waterfront here.”

In the winter, according to Masi and Sewall, the annual freeze usually kills off a chunk of the local green crab population. However, amid warmer winter temperatures in recent years, green crabs have been able to remain alive and active, feeding on soft-shell clams, tearing up eelgrass and eroding marshbanks as they excavate and scour for food. 

A single green crab can consume upwards of 40 half-inch soft-shell clams in a day, according to the Gulf of Maine Institute.

The green crab invasion is apparent in the state’s statistics on soft-shell clam landings. In the mid-1970’s, Maine fishermen caught nearly 40 millions of pounds of soft-shell clams per year. But last year, fishermen caught approximately 5 million pounds of soft-shell clams in Maine waters.

Sewall was 8 years old when he received his commercial lobster license from the state. He’s seen the change in the local supply of soft-shell clams and the growing impact of green crabs.

“There’s no clams left in the York River,” he said. “Even when I was a kid, I remember being able to go out and dig a whole meal for the family in an hour.”

Among all commercial catch in Maine in 2023, just 3% of the total was attributed to soft-shell clams. The state’s report shows lobster made up 46% of all commercial catch in Maine last year. The entire year’s worth of commercial catch in Maine last year tallied almost 205 million pounds and totaled over $600 million in value, according to the state.

“Clams are historically a very, very important part of the coastal economy. We’ve seen that drop off significantly,” Masi said.

The Shell + Claw co-founders hope that other Maine fishermen, namely oyster farmers, could be interested in harvesting green crabs in the future to revive the soft-shell clam population and fill in a gap in the offseason for those fishermen.

Beginning on Earth Day next year – April 22, 2025 – Shell + Claw will launch a state-approved oyster and green crab farm in the York River, an experimental lease set to last for three years. There, Masi and Sewall hope to show more local fishermen the benefits of green crab harvesting and encourage them to follow suit while perfecting their own trapping processes.

“We think that green crabs could fill that little niche and be a supplementary income for interested oyster farmers that want to pull in a little bit more money in May and June,” Masi added.

But is the business of green crabs a profitable one? 

Hard-shell green crabs trapped by Shell + Claw have been sold to a single buyer in Rhode Island, whose fishermen use the species as bait to catch channeled whelk, a predatory sea snail. 

Dating back to 2022, Shell + Claw reports having sold 48,000 pounds of hard-shell crab. At $0.60 per pound, the York business has made just shy of $29,000 from bait sales alone. However, the bait market has at times been unreliable for Shell + Claw, as channeled whelk buyers in China have not always needed Rhode Island fishermen to go out and fish for the snails.

Shell + Claw has sold about 1,600 soft-shell green crabs each year to restaurants at around $3 per crab, resulting in nearly $5,000 in additional sales.

From what they hear from their customers, though, the more green crabs Shell + Claw can harvest and sell, the better.

“We could triple our production and probably not meet the demand, just from what we have right now,” Masi said. “The chefs have been great and they know that we’re in the research and development phase, but to become more of a business, we’ve got to be able to more consistently produce product.”

Shell + Claw sells soft-shell green crabs to four restaurants, according to the co-founders – Portsmouth, New Hampshire restaurants Black Trumpet bistro, Botanica Restaurant and Gin Bar and Row 34, in addition to Moeca in Cambridge, Massachusetts. 

“It’s tough for a restaurant to not know what they’re going to get because they want to make a menu,” Sewall said. “Line cooks, if they get trained on something and then it’s gone the next day, it’s just a big waste of time. So we’ve got to be able to give them a steady supply for a month or two, whatever the season is, so they can have it that whole time.”

A goal of Masi and Sewall is to conduct outreach to people of southeast Asian descent living around New England, as Cambodian, Filipino and Vietnamese consumers have shown strong interest in Shell + Claw’s green crabs. 

Seacoast chef says soft-shell green crab meat taste is sweet

Chef Jeremy Sewall, managing partner of the Row 34 seafood restaurants, was skeptical that green crabs would be deemed tasty enough to ever be appealing to diners. Now, he’s a green crab convert.

“Having spent a lot of time on the York RIver in Maine as a kid, they were kind of gross,” he said of green crabs. “They were in the mud and I thought they would taste muddy and a little earthy. They’ve actually got a nice sweetness to them. It’s a nice sweet crab meat.”

Sewall, a cousin of Sam Sewall, is a James Beard Foundation-nominated chef and received his training at the Culinary Institute of America. His career has taken him to London, Amsterdam and California before returning to his New England roots. Row 34, of which he’s a partner with Shore Gregory, has grown to include locations in Portsmouth, New Hampshire and three in Massachusetts, with restaurants in Boston, Burlington and Cambridge. 

Jeremy Sewall and the Row 34 staff have been serving green crab at all four locations since the start of Shell + Claw’s harvesting efforts. The crustaceans have been served two ways by Row 34, either fried and served on a slider, or chopped up and served with seasonal vegetables in a pasta dish.

“They’re just really good. It’s another tasty seafood that I think New England has to offer,” Jeremy Sewall said.

Due to the bulk of harvesting being conducted in the spring and summer, Row 34 is not currently offering green crab on its menu. But the business will again in the future, continuing a partnership with Shell + Claw that is a first-of-its-kind initiative for the Row 34 brand.

Chefs at Row 34 have had to become innovative in preparing a menu with lesser-known fish due to the occasional shortage of more popular species.

“We’ve had to rely on other species from a seafood standpoint because the ones we tend to like, we’ve eaten all of them,” Jeremy Sewall said. “Eating a diversity of creatures out of the ocean is a great thing.”

But in the chef’s mind, for New England’s soft-shell clam population to boom once more, green crab harvesting and marketing efforts need to expand. It can’t just be up to seafood lovers to endlessly eat green crabs out of existence, he added.

“It’s got to go beyond restaurants to really make an impact on the green crab population,” Jeremy Sewall said. “You’re going to need to get it into the mainstream diet and in front of more consumers rather than (just at) a bunch of small restaurants around New England.”

Shell + Claw attemping to streamline their process

Another next step in Shell + Claw’s growth is to become more efficient in identifying green crabs that are about to molt. Rather than go through each crab one by one, Masi and Sewall hope to be able to locate green crabs that are about to transition into a softer shell just by looking into a trap or tray full of the crustaceans.

In the early days of their startup, Masi and Sewall would check on the pre-molt green crabs every 12 hours, sometimes trudging into the dark of night to observe their catch and separate the crabs. 

“We’re putting a lot of man hours in when we’re actually sorting these every day between us and the interns,” Sewall stated. “If we’re going to make it a business, we have to pay these people and then make a little ourselves.”

While the number of green crabs in the Gulf of Maine is anecdotally high, Shell + Claw’s operation is still relatively small. The business has 30 green crab traps and a homemade “crab condos” where the captured about-to-molt crabs are placed before being sold to restaurants. By comparison, Sewall owns 800 lobster traps.

But amid the uncertainty of the soft-shell clam population, and state fishermen bringing in the lowest amount of lobster in 15 years in 2023, Masi and Sewall see green crab harvesting as a way forward for those trying to make a living on the docks. 

“I think that those that are going to be successful in the working waterfront in the years to come are going to be the individuals that are nimble, that are willing to try new things,” Masi said.

Green crab bounty program in Massachusetts seen as crucial for soft-shell clamming industry

In Ipswich, Massachusetts, historically teeming with soft-shell clams, officials have initiated a town- and state-funded green crab bounty program that pays fishermen to catch and dispose of the crustaceans. The program pays a select group of fishermen $0.40 per pound of green crabs that they catch and remove from the water.

Last year alone, a total of 85,838 pounds of green crabs were trapped and taken out of Ipswich waters, according to town Shellfish Constable Matthew Bodwell. In turn, over $34,000 was paid to the fishermen that caught them, while thousands more pounds of green crabs were caught in the town outside of Ipswich’s program.

Green crabs are “the most dangerous threat to Ipswich shellfish populations,” Bodwell says, and taking them out is “essential to the future of our clamming industry.”

“Green crab trapping is a very important program that has been, and continues to be, effective in lowering overall green crab numbers,” he said. “This in turn allows more juvenile soft shell clams to grow to harvest size, protects the Great Marsh from the destructive burrowing of the crabs, and protects eel grass from being eaten by the crab. Trapping, in my opinion, is the best solution for sustaining clam populations and protecting our marshland.”

Back in York, Masi believes Shell + Claw’s unofficial study has had a mirroring effect in rejuvenating the soft-shell clam population in Braveboat Harbor. 

By removing tens of thousands of pounds of green crabs themselves, slowly but surely, some soft-shell clams are living longer.

“I am seeing some inch-and-a-half-sized clams and those ones definitely settled within the time period that we’ve been working there and when we’ve been harvesting (for green crabs),” Masi said. “I think we are seeing that we’ve done some ecological good in trying to protect the clam resource.”