Oyster Reef Construction in the Squamscott River

Improving Water Quality, Providing Habitat and Removing Nitrogen

Newmarket, NH | June 19, 2012

The Nature Conservancy’s New Hampshire Chapter (TNC) is continuing efforts to restore habitat and improve water quality in the Great Bay Estuary by constructing 2 acres of oyster reef in the Squamscott River.  In total, over 50 tons of recycled clam and oyster shell will be deposited into the river to form the reef.  Work at the site will continue through Wednesday.

A barge crew, along with TNC and UNH scientists, will deposit shell on the river channel bottom in carefully arranged plots. The thin layer of shell acts as the foundation for oyster spawn to set on naturally, and will provide a base for thousands of disease-resistant juvenile oysters to be placed.  These juvenile oysters have been raised by volunteers and at a UNH hatchery. Once the annual spawn is over and the hatchery work is complete in the fall, about 500,000 new oysters are expected to reside on these new reefs.   One adult oyster can filter 20 gallons of water per day, and an acre of healthy reef controls as much as 1 ton of nitrogen per year.

“Oysters may be Great Bay’s best hope for sustainable recovery of our estuary.” said Dr. Ray Konisky, Director of Marine Science for TNC.  “These reefs provide habitat for a diversity of plant and animal life, and oysters are amazing at filtering and removing nitrogen from the water. Right now, the estuary has a major problem with excess nutrients including nitrogen which is negatively affecting water quality.  Our cities and towns are grappling with ways to meet requirements to upgrade facilities to remove this nitrogen from wastewater. We want to complement those efforts by re-establishing healthy oyster reefs at a scale that will help improve water quality and bring the estuary back into balance.”

Vast reefs of live oysters once covered the bottom of the Great Bay Estuary, filtering out excess nutrients, providing habitat to a diversity of fish, and offering recreational harvest to generations of locals. But due to pollution, disease and over-harvest, New Hampshire has seen 90% of its reefs disappear since 1990 –a devastating loss for the estuary.

In order to begin reversing this trend, TNC and UNH formed a partnership to restore some of the lost oyster reefs. Construction techniques with clam shell were started with a pilot study in 2009, expanded to a more than an acre in 2010 in the Oyster River (Durham), and doubled again in 2011 in the Lamprey River.  The Nature Conservancy’s goal is to restore 50 acres of oyster habitat by 2020 – a fraction of the historic reef, but a substantial and important strategy towards improving overall water quality in the estuary.

“Oyster restoration is important for the future health of the Great Bay Estuary, but we need to remain focused on the big picture,” continued Konisky.  “We need to scale up oyster restoration, and we also need to address stormwater runoff, our aging wastewater infrastructure and other sources of nitrogen pollution if we are to be successful in restoring water quality over the long term.  Through our oyster work and other efforts, The Nature Conservancy is committed to finding and implementing solutions that benefit the estuary and our communities.”

Community support is an integral part of the restoration program.  In addition to supporting reef construction, community volunteers are a big part of the oyster restoration success.  Now in its seventh season, the NH Oyster Conservationist Program engages dozens of homeowners around the Bay who raise juvenile oysters on their docks that are later placed on the restoration reefs.  In addition, the UNH Docents provide labor for some of the shell handling duties.  Another partner is the Coastal Conservation Association (CCA) which operates a NH and ME oyster shell recycling program with restaurants that recovers about five tons of shell per year for hatchery and reef enhancement operations.  

Funding for oyster restoration comes from a variety of federal, state, and private sources.   Lead funders include the Piscataqua Region Estuaries Partnership, NOAA Restoration Center, Natural Resources Conservation Service, State of NH Conservation License Plate Program (Moose Plates), and many private donors.

For more information about reef construction and the Oyster Conservationist Program, visit www.nature.org/nhoysters.  For information about the restaurant shell recycling program, go to www.ccanh.org.  


The Nature Conservancy is a global conservation organization dedicated to conserving the lands and waters on which all life depends. Guided by science, we create innovative, on-the-ground solutions to our world's toughest challenges so that nature and people can thrive together. We are tackling climate change, conserving lands, waters and oceans at unprecedented scale, and helping make cities more sustainable. Working in more than 65 countries, we use a collaborative approach that engages local communities, governments, the private sector, and other partners. To learn more, visit www.nature.org or follow @nature_press on Twitter.

Contact information

Jim O'Brien
Director of External Affairs
The Nature Conservancy in NH
22 Bridge Street, 4th Floor
Concord, NH 03301

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