Marissa McMahan grew up in midcoast Maine, attended Georgetown Central Elementary and spent glorious days of her childhood on her father’s lobster boat.

“I was always really curious about what I saw in the water,” she said. “Even as a young kid, I had a five-gallon bucket. It became my aquarium. I collected different species, and then poured it back when we returned.”

Dr. Marissa McMahan collects data on green crabs at a dock in Georgetown. Gregory Rec/Staff Photographer

These days, Dr. Marissa McMahan visits Georgetown Central, among other schools, passing on her curiosity – and her knowledge – of local species in the Gulf of Maine, and invasive species, especially the notorious green crab.

The unwanted green crab has wrought havoc on local shellfisheries, presenting McMahan with a challenge and opportunity. McMahan, 34, is a marine biologist and the Fisheries Division Director of Manomet, a Massachusetts-based sustainability nonprofit center. She is our 2020 Source “Invasives Innovator” award winner.

McMahan stands on a dock in Georgetown after finishing collecting data on green crabs. McMahan is the winner of the Invasives Innovator Award from the 2020 Source Sustainability Awards. Gregory Rec/Staff Photographer

McMahan transferred her childhood curiosity to science classes at Morse High (Class of 2003), eventually earning a Master’s in Marine Biology from the University of Maine, and her Ph.D. from Northeastern University.

“She loves the science – can geek out at the numbers,” said Anne Hayden, a Manomet colleague who nominated McMahan. “And she grew up in a fishing community and it’s part of who she is. Her science is not just curiosity-based, but how can we make things better for the fishing communities.”


McMahan said her family, on her father’s side, has lived and fished in Georgetown, going back to the 1700s. “My father and uncle are lobstermen. My grandfather is a retired lobsterman … I worked on my father’s boat in high school.”

She has been researching the green crabs in the Gulf of Maine since 2017. “They’re very devastating to ecosystems – they consume softshell clams and mussels; they uproot eel grass and salt marsh habitat,” she said. “They have a very negative impact.”

McMahan’s hopeful solution? “If you can’t beat them, eat them,” she said. “We’re working on developing markets … What we would like to focus on is having some sort of benefit for the fishing community – diversify what they’re fishing for.”

McMahan picks up a green crab while collecting data on the invasive species at a dock in Georgetown. Gregory Rec/Staff Photographer

Green crabs can be used for bait for hook-and-line fisheries; and there is also a growing demand for soft-shell green crabs from restaurants. “The West Bath School students actually came up with recipe ideas, making stock or broth,” she said. McMahan speaks at several schools, and works often with Georgetown Central and West Bath students on field projects and marine studies.

“She is highly effective in relating science to children,” said Georgetown teacher Susan Ayers, who has worked with McMahan for the past five years. “Marissa is incredibly intelligent, passionate about our natural environment, indomitable in her research and field work, and extremely unpretentious … she is a gem in the classroom.

“She is so connected to this area: the land, the sea, the people, the industry. My students see her love and concern for the marine resources and the implications of our changing world on the fishing and harvesting in Georgetown. Marissa informs people and gets them motivated to be on board.”

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