The centrality of the wild native eastern oyster to New England’s ecology, economy and culture should be beyond dispute, yet the population has been on the wane for decades.
As part of the effort to help stem and reverse this decline, The Nature Conservancy in Massachusetts and partners, including the towns of West Tisbury and Chilmark and the Martha’s Vineyard Shellfish Consortium, have embarked on a one-acre oyster-bed restoration in Tisbury Great Pond. Now underway, the project—an addition to ongoing oyster restoration efforts in the pond—is intended to kick start a self-sustaining wild oyster reef and also provide a template for future shellfish restoration in the Commonwealth.
The 736-acre Tisbury Great Pond is a natural coastal pond that currently supports populations of oysters and soft-shell clams. It’s located in West Tisbury and Chilmark, and the two towns are sponsoring the project, including providing volunteers through the local shellfish advisory committees.
West Tisbury and Chilmark have been successfully managing their oyster resources for many years to ensure a public fishery, including placement of shell on harvested areas. The current project is meant to augment the oyster resources in Tisbury Great Pond in connection with this long-term stewardship of the resource and builds on methods the towns have pioneered.
The Martha’s Vineyard Shellfish Group, a nonprofit consortium of municipal shellfish departments on the island, is growing juvenile oysters to seed the new project, while the Conservancy is financing the work and has used its expertise gained in other, similar efforts to design the project.
“We know healthy oyster beds filter water, remove polluting nutrients and provide important fish habitat—services with environmental and economic value,” said Jon Kachmar, the Conservancy’s Southeast Massachusetts program director. “The Nature Conservancy’s long-term goal is to restore these ecosystem services that have been lost to Massachusetts estuaries as historic oyster beds have been destroyed by disease, overharvest and poor water quality.”
“We’re developing, implementing and documenting methods that will be directly transferrable to large-scale recovery of oyster habitat,” Kachmar said. “In the case of Tisbury Great Pond, the towns and island partners deserve great credit for sustainably managing the oyster fishery in the pond for decades. Their success is the key reason for this work is happening here. We hope to help build upon that success.”
Oyster beds begin to develop when free-floating oyster larvae attach themselves to hard surfaces. From that point, the larvae—called spat—can mature and eventually become full-size oysters.
The Great Tisbury Pond project primarily is using surf-clam shell to create the hard-surface foundation for the one-acre oyster bed.
The shell was transported starting in early June from Wareham and has been staged at Sepiessa Point in West Tisbury. On the weekend of June 22-23, it was loaded onto a barge for transport to the restoration site in the northwest corner of the pond, an area known as Town Cove. Then, the towns and the Conservancy coordinated volunteers to place the shell in the water.
The Conservancy and University of New Hampshire have piloted shell-planting for conservation in the Northeast using primarily clamshell and have demonstrated that clamshell is capable of attracting and retaining oyster larvae.
University of New Hampshire research also has shown that placement of young oysters can greatly enhance natural recruitment of wild oysters to a restoration site since it reduces predation during the first year. Because of this, about 250,000 juvenile oysters—attached to clamshell and called spat-on-shell—will be grown in a hatchery and placed on the bed’s foundation to aid in the bed’s development.
The spat-on-shell will be grown by Rick Karney, shellfish biologist and facility director with Martha’s Vineyard Shellfish Group. Interns from Boston with the Conservancy’s Leaders in Environmental Action for the Future are scheduled to help with some of the work required to support this part of the project.
“While a great number of oysters are needed to make a serious impact on water quality and Tisbury Great Pond’s ecology, their fecundity is reason for optimism,” Karney said. “Save setbacks due to disease, predation or environmental problems, with years of successful expanded seeding efforts, we should expect to see exponential increases in natural recruitment of oysters.”
The work getting the oyster bed in place should wrap up in early- or mid-August.
Pre- and post-monitoring to determine project success will occur over a period of two years. The work will be done in conjunction with Northeastern University’s Marine Science Center.
“The Town of Chilmark recognizes the importance of this project,” said Chilmark shellfish constable Isaiah Scheffer.
Tisbury Great Pond historically has produced a great quantity of oysters that were commercially harvested, he said. During fruitful times, many of the harvested oysters were used for the shucked, out-of-shell oyster market. This processing left behind the shells, which were then put back into the water to catch the naturally occurring seed sets that would replenish the population.
“The current demand for smaller oysters—on half-shell market—has created a gap in the cycle,” Scheffer said. “Shell that was once returned to the water is now being discarded, resulting in a gap in the shell budget. Without the extra substrate for spat to attach, the oyster population easily comes under stress.
“Restoring an oyster reef will not only improve water quality; it will promote species diversity and be a lifeline for areas where oysters haven’t been able to flourish.”
The Nature Conservancy is a leading conservation organization working around the world to protect ecologically important lands and waters for nature and people. The Conservancy and its more than 1 million members have protected nearly 120 million acres worldwide. Visit The Nature Conservancy on the Web at www.nature.org.
Media Relations Manager
The Nature Conservancy in Massachusetts