Maine researchers and entrepreneurs continue to work hand-in-hand to identify a sustainable market for the destructive green crabs wreaking havoc in Maine’s $17 million softshell clam industry. Green crabs are predators that feed on soft shell clams, Maine’s third largest fishery.

The Department of Marine Resources (DMR) reported that between 2012 and 2013, the state’s soft shell clam landings declined from 11.1 million pounds to 10.6 million pounds. The DMR attributed at least part of the decline to destruction by green crabs.

“We’d be killing two birds with one stone if we remove the destructive species from the environment and find a useful purpose for those as well,” said Darcie Couture, the owner and lead scientist of Access International, a Brunswick-based marine biotoxin monitoring company.

The Bangor Daily News reported earlier this summer that North Carolina-based Bay City Crab purchased two tractor-trailer loads of green crabs from Boothbay Harbor harvesters, processed them at its plant, and shipped the crabmeat to a cat food company.  Bay City’s plant manager later said the harvesters refused to continue harvesting green crabs because they weren’t paid enough. The plant manager reportedly told the harvesters that if they could work with her until she could make the market stronger, she might be able to increase the 25 cents per pound they previously received. 

Arundel-based entrepreneur John der Kinderen said the cost of harvesting green crabs is a real problem. He’s invested in the development of a new trapping system that would dramatically decrease the cost of harvesting.

Der Kinderen, a retired science teacher and businessman, received a grant from Maine Technology Institute last April for a project in which he’s examining the feasibility of marketing both shells and meat from green crabs.  He has been working with different industries to find an efficient way to extract chunk meat from green crabs (usually 2- to 5-inches long) and to market for animal feed and human food. He has found a piece of equipment that can extract the chunk meat.

“It’s high quality crab meat and extremely marketable,” he said. “If there’s no domestic market here, China will take all they can get.”

Der Kinderen’s also examining the possibility of marketing chitin, which is a sugar found in the shells of crabs, shrimp, and lobsters. Chitin (in various forms) has already been marketed for medical purposes such as the chitosan-based hemostatic dressings used to treat battle wounds in Iraq and Afghanistan.

Der Kinderen said he started with a very crude level of chitin, hoping to work up the ladder to higher grades, which could be marketed for higher end pharmaceutical uses and possibly even reconstructive surgery, with those products being even more profitable.

Couture of Access International said the green crab population overall has declined this year in Maine compared to last year, which was a hindrance to efforts to develop a sustainable market. Couture has been part of an effort to target traps in intertidal areas around Brunswick where green crabs were seen last year.  Only 459 pounds were landed in Buttermilk and Woodward Coves, which seemed to indicate the green crab population was diminishing.  But a large population was discovered in Cohog Bay.

Cohog Bay Conservancy set 100 traps for green crabs this past summer, and Couture said 5,000 pounds were landed from those traps, which were tended on a regular basis. The green crabs there were much bigger than most of the others she’s seen in Maine.

“It could be because they’re much closer to direct ocean influence,” Couture said.

As the result of rule changes by DMR, commercial fishermen no longer need a special license to harvest and sell green crabs and they are no longer required to report green crab harvests. Lobstermen are able to take them as a bycatch. Also, when the Sheepscot, Damariscotta, and Medomak rivers are closed for fishing other crab species—Dec. 1 to April 30—fishermen can continue harvesting  green crabs from those areas. The rule changes are part of the growing effort of both the public and private sectors to decrease the population of green crabs in Maine waters.