Clean Water and Quahogs: Changes in Narragansett Bay

Quahogs, also known as hard shell clams, are a popular, simple to gather shellfish. Whether served as stuffies or chowder, quahogs are a staple in New England. They have a long history in the region, dating back thousands of years to when they were harvested by the Narragansett, Pequot, Wampanoag, and other local nations to make food, tools, and art.

To protect public health from contaminated shellfish, state agencies regulate where shellfish can and cannot be harvested for direct human consumption.

Shellfish are filter feeders, meaning they strain suspended matter and food particles from the water around them, including plankton and bacteria. This makes them sensitive to pollution, especially harmful bacteria and biotoxins.

Potential sources of pollution include discharge from wastewater treatment plants, marinas, septic systems, and stormwater runoff.

All approved and conditionally approved areas are sampled for fecal coliform bacteria and harmful algal blooms six to twelve times per year.

By identifying and eliminating sources of pollution, water quality has improved and more areas have been opened to shellfishing.

The newly opened area in the lower Providence River is an ideal place to harvest shellfish, with shallow water and broad swaths of silty sand and mud. Having gone so long without being harvested, the quahogs in the area are thriving and abundant. In fact, the quahog population in the lower Providence River may act as a source of larval quahogs, which are transported throughout the bay by currents. To ensure the long term sustainability of this fishery, Marine Fisheries limits harvesting in this area.

In addition to large-scale projects like RestoredWaters RI, local efforts to improve stormwater drainage and septic systems have helped reduce bacteria and pollution throughout the bay.

More shellfishing areas is not the only potential benefit of cleaner water; recreational activities like kayaking and swimming are also impacted by water quality. Activities that involve direct contact with the water have to pass additional bacteria and water quality tests, however. Should the water quality continue to improve, the end goal is an urban beach.

For detailed, up to date information on shellfish availability and closures in your area, please consult your state's website:

• Connecticut ( link )
• Massachusetts ( link )
• Rhode Island ( link )

To learn more about RestoredWaters RI, check their  website .

Shellfish data from the Massachusetts Division of Marine Fisheries (MADMF), Rhode Island Department of Environmental Management (RIDEM), and Connecticut Department of Agriculture - Department of Aquaculture (CTDABA) were reconciled to obtain a seamless shellfish growing area dataset at different time sets. The Estuary Program defined three categories derived from the shellfish growing area classification systems used by Massachusetts and Rhode Island:

• Approved: Growing areas where shellfish harvesting is allowed for direct human consumption all year round (some exceptions may apply)

• Conditionally Approved: Growing areas where shellfish harvesting is allowed for direct human consumption with some restrictions, depending on each state’s shellfish program criteria

• Prohibited: Waters where shellfish harvesting is not allowed for direct human consumption

For the purposes of this storymap, shellfish growing areas used for controlled relay and depuration are considered prohibited.

For a detailed description of the methods used to process the data, see the  2017 State of Narragansett Bay technical report .