DV-17-03 Investigating the viability of a soft-shell green crab industry in Maine

Marissa McMahan
Northeastern University
Nahant, MA 01908

The European green crab, Carcinus maenas, is an invasive species in coastal Maine that threatens the commercially important soft shell clam (through predation) as well as lobster (through competition for shelter and food resources). In response, fishermen and resource managers throughout Maine are experimenting with ways to eradicate green crabs, minimize their damage, and identify possible uses for the animals. McMahan’s research aims to inform development of a wild-harvest soft-shell crab fishery that would cull green crab populations while supporting a profitable bycatch fishery for lobstermen. This fishery is modeled after a traditional harvest of Moleche, Carcinus aestuarii, a type of soft-shell green crab considered a delicacy in Venice, Italy.

In the summer of 2016, McMahan led a team of researchers, fishers and local residents in a Sea Grant-funded project to begin investigating the viability of a soft-shell green crab fishery in Midcoast ME (DV-16-10). With training from a visiting Venetian crab fisherman, they successfully identified pre-molt green crabs, using subtle but distinct color changes on the ventral margins of the abdomen and platelets.

In this second phase of the project, McMahan and her team conducted a trapping study to identify spatial and temporal patterns of green crab abundance and molting, as well as the continued study of external pre-molt indicators. They tested the type of gear required to harvest and store pre-molt crabs. They traveled to Venice, Italy and participated in the traditional soft-shell crab fishery during peak harvesting, in an effort to gain understanding of the fishery and apply traditional techniques to efforts in Maine. Students, local residents, and business owners helped with monitoring and producing soft-shell crabs. In 2017, several chefs experimented with cooking soft-shell green crabs and featured the product as a menu item to high demand, representing the first time soft-shell green crabs have been served in the United States and demonstrating the market potential for soft-shell green crab.

Sea Grant funds: $4,000