Shellfish Aquaculture

Falmouth is leading several demonstration projects to test the ability of various methods to help remove nitrogen from its estuaries. One of them is the Falmouth Shellfish Aquaculture Demonstration Project, a joint initiative of the Water Quality Management Committee and the Department of Environmental Conservation, which began in 2013 when over 1.25 million oyster seeds were placed in Little Pond.  In 2014 and 2015, two million oysters were seeded and cultivated to around one inch in size in Little Pond before being transferred to Green Pond and West Falmouth Harbor to mature and filter more water.  Read more about the project on the Town’s website and watch a video about the project here

oystering in west falmouth 2

Oystering in West Falmouth Harbor. Photo by Chuck Martinsen.

In Falmouth’s ponds and estuaries, excess nitrogen from septic system effluent and surface water runoff causes excessive growth of nitrogen‐feeding plankton.  As these microbes die and decompose, the water becomes oxygen‐depleted, smelly, and cloudy, which has harmful effects on plants, fish, animals, and people.

One possible piece of the solution is to use shellfish, which feed on microbes, organic particles, oysterbagsnitrogen‐containing compounds, phosphates, and other materials in the water column, thus removing them from the water and absorbing them into their own tissues.   Oysters, in particular, are very effective filter feeders, with adults reportedly able to consume plankton and other nutrients from up to 50 gallons of water each day.   The hope in Falmouth is that oysters will be able to manage plankton concentrations and reduce nitrogen levels in Little Pond and other estuaries, ultimately leading to improved water quality.

A water quality monitoring team will work with the aquaculture project over the course of its three‐year expected time span to sample water and estimate the amount of nitrogen removed from the system by the shellfish.

As a secondary benefit to the community, once oysters reach suitable adult size, they will be transferred to other, cleaner estuaries in Falmouth where they can “clean out” in preparation for commercial and recreational harvest.  This process, called depurating, gives the oysters time to flush from their systems any pollutants they have gathered in the nitrogen‐rich Little Pond.  The first batch of oysters was harvested in Fall 2014.

For information on harvesting oysters in Falmouth, see the Town’s regulations and open areas here

So far, residents report visible improvements in water clarity in Little Pond. We look forward to seeing the results from the monitoring studies and support these projects as part of an integrated wastewater management plan.  Stay tuned for updates!

Watch MBL’s Scott Lindell Discussing ‘Oysters: Our Briny Bioengineers’ HereScottsOysterTalk

Benefits of Oyster Aquaculture
  • Shellfish, particularly, oysters, are very effective at cleaning degraded waters.
  • Once the shellfish have filtered the waters and had time to flush out, they can be harvested and eaten.   
  • Shellfish farming is a sustainable system of food production; it does not require fertilizers, feeds or chemical inputs.
  • Shellfish aquaculture provides habitat for juvenile fish, crabs and other creatures.
  • Oysters not only remove nitrogen, phosphorous and other pollutants from the water, they also greatly improve water clarity. 
  • Oyster farming has been practiced on Cape Cod for decades. Local oyster aquaculture projects preserve this historic way of life.