The first time Sam Cheeney saw a green crab was in the early 2000s, as part of an ecology class at the University of Maine at Machias.

He and his classmates ventured out across the mud flats and rocky shoreline in search of the invasive species, one that research suggests has been present on Maine’s coast since the mid-1800s, when it was carried to North America in the ballast waters of a European ship. Today, green crabs prey on soft-shell clams and mussels and have been found to harm salt marshes. 

“We would find pockets of just hundreds of them,” Cheeney said. The experience made an impression. In 2023, after stints as a farmer and carpenter, and more than two decades after his first glimpse of the green crab, Cheeney founded Green Kraken, a small business based in Milbridge that makes fertilizer from crushed green crabs. The nutrients in the green crab act as a stimulant for vegetables and other crops. 

For Cheeney, using crab meal as a fertilizer is about more than mitigating the invasive species’ impact on the Gulf of Maine’s ecosystem, though that’s a part of it. The other part of Cheeney’s mission goes back to his days as a farmer. While addressing fertility issues with his crops, Cheeney said he spent a lot of time thinking through the sustainability of his farm inputs. 

“A lot of nutrients are mined, or they’re made from petroleum,” he said. Green crab emerged as a more sustainable, low-carbon alternative that was also local. He now sells his fertilizer in retail stores from Rockland to Machias and distributes it across New England. 

Cheeney is not alone in his efforts to curb the green crab by transforming it into something new. 

In South Portland, Marpheen Chann is taking a different approach: he’s working with the Fork Food Lab to find ways to add green crab to seafood dishes across Maine. Chann is the executive director of Khmer Maine, a nonprofit that works with Maine’s Cambodian community.

In Cambodia, there’s a species of crab that burrows into rice paddies, creating a nuisance for farmers. There, Chann said people have begun incorporating the crabs into their diets, taking the form of crab paste, minced crab and salted crab. 

“If you think about it, it’s not anything really new that our community here is taking a look at green crabs and sort of seeing the same problems,” said Chann.

This year, Khmer Maine’s food incubator program is doing a test run to see if there’s a market for green crabs among Maine’s Southeast Asian communities. Chann is at the helm: when we spoke last week, he told me he was “elbow-deep in green crabs.” 

That work includes processing hundreds of crabs sourced from the Quahog Bay Conservancy, putting them in buckets with garlic, sugar and fermented fish sauce, and then packaging them to be flash frozen and stored for consumption later this fall.

Despite losing out on some USDA funding because of federal cuts, Chann said he’s hopeful that Khmer Maine can eventually expand its market for green crabs into Massachusetts. 

These business efforts are ramping up as green crabs are becoming more and more abundant as a result of warming waters. 

“They’re really thriving under climate change conditions,” said Marissa McMahan, senior director of fisheries at Manomet Conservation Sciences, explaining that warmer winters mean that more green crabs can survive and continue to grow all year long, leading them to reproduce sooner than in the past. “We’re just kind of seeing this population explosion at this particular point in time.”

Manomet established monitoring sites to track green crab population trends in 2018. Over the last seven years, McMahan said, there’s been a significant increase. 

Taking a break from the fermentation buckets, Chann told me he sees an opportunity there, not only in helping to mitigate a threat to Maine’s ecosystem but in promoting cultural exchange.

“We’re educating people, not only about Cambodian culture and what Cambodian cuisine and the diet is like, but also saying, ‘hey, we’re here to help,’” Chann said. “This is an issue in Maine, and fortunately enough, it happens to be a cultural fit with our community.”

This story was originally published by The Maine Monitor, a nonprofit civic news organization. To get regular coverage from The Monitor, sign up for a free Monitor newsletter here.