The Damariscotta and Sheepscot Rivers in Maine’s midcoast region are home to unique systems whose tidewater flats support a variety of shellfish, including softshell clams, quahogs, blue mussels, oysters, and others. The surrounding areas rely on shellfish income year-round. Currently, the Damariscotta/Newcastle Joint Shellfish Committee is interested in understanding observed population fluctuations that are impacting harvester livelihoods.
To better understand the current state of shellfish populations in the Damariscotta River and Medomak River estuaries, the Damariscotta/Newcastle Joint Shellfish Committee along with the University of Maine Darling Marine Center (DMR) formed a group and are conducting shellfish population surveys, recruitment experiments, and interviewing local harvesters.
In 2019, the Damariscotta-Newcastle Shellfish Committee commissioned the University of Maine Darling Marine Center (DMC) to study the shellfish resource in the Damariscotta River estuary mudflats. This project involved interviewing local shellfish harvesters and collecting biophysical data along sites in the Damariscotta River estuary. The intention of this project was to define an ecological baseline and cultivate partnerships between harvesters, researchers, and others. This project worked with current and retired shellfish harvesters to identify shellfish population fluctuations, as well as used standardized intertidal transects to create a participatory map of shellfish populations.
This work was led by Matt Lutkus, the Damariscotta Town Manager; Ryan Fraser, a shellfish harvester and chair of the Damariscotta/Newcastle Joint Shellfish Committee; Dr. Kara Pellowe, a sustainability scientist that worked at the Darling Marine Center in Walpole, ME; and Mick Devin, a local state representative and member of the shellfish committee.
This worked laid the groundwork for larger, more expansive surveys, further interviews and community outreach or engagement, and continued integration of environmental and harvester knowledge data, that continues today. A final report from the work in 2019 can be read by clicking the link below.
Environmental data was derived from intertidal transect methodologies. At multiple locations within the Damariscotta River Estuary, a 25m transect was laid parallel to the shoreline. Five sample quadrants that are one square meter were organized along this transect. At each quadrant, researchers record physical and ecological data points including percent cover of algae, rock coverage, number and dimensions of shellfish. Surveyors also identified if predator species such as bloodworms, sandworms, milky ribbon worms, and invasive green crabs were present.
This environmental data was then organized into a map, highlighting how concentrations or presence of species changed across the coast, creating a new and full picture of ecosystem dynamics and populations in this area.
Harvester’s local environmental knowledge is considered crucial for effective stewardship by the group leaders. DMC graduate students including Sarah Risley and Melissa Britsch and advisors Dr. Josh Stoll and Dr. Heather Leslie created local mapping surveys to ask commercial clam harvesters on their observations of changes on the river, shellfish population ships, and other challenges within the shellfish fishery. These conversations guided site selection for monitoring sites and provided some explanations for changes in the ecosystem.
The DMR research team is also working with other community partners to make this work more continuous. More recently, researchers worked with the Newcastle-based Lincoln Academy to create student projects based on documenting local ecological knowledge and contribute to environmental monitoring.
Building capacity for sustained monitoring and community stewardship of the shellfish resources and ecosystems of the Damariscotta River Estuary: This project, started in 2021, will be focused on further targeted ecological surveys and ecological knowledge surveys to understand new or intensified fishery use, recreational use, and shifting environmental conditions. This work will be shared in Spring 2022 and presentations at the 2022 SEA Fellows Summer Student Science Symposium.
Recruitment boxes placed on flats on the Newcastle side of the Damariscotta River estuary
Darling Marine Center staff and interns conduct interviews with harvesters
Recruitment boxes removed and studied at Darling Marine Center in Walpole
Start of monitoring and community stewardship project in the Damariscotta River