Part of the Tisbury Great Pond is about to become an oyster reef, thanks to a project sponsored by The Nature Conservancy and the towns of Chilmark and West Tisbury.
The propagation projects calls for putting down 100 cubic yards of sea clam shells as culch and then planting 250,000 juvenile oysters. The area, which is just under an acre with the town line running through it, is marked by blue buoys in the center of the pond and is not actively fished by commercial fishermen.
“We’re creating a sanctuary,” Chilmark shellfish constable Isaiah Scheffer said during a tour of the pond this week. “There are oysters around this area. What we’re attempting to do is restore oysters in an area that hasn’t had them in some time.
“Putting shell in the water is the easiest and most effective way, as long as you get a natural seed set, which requires a bit of luck,” he added.
The shells and oysters will go into the pond late this month. The oysters are being grown by the Martha’s Vineyard Shellfish Group.
The goal of the project is to create a functioning oyster habitat and at the same time improve water quality in the pond by removing nitrogen, said southeast Massachusetts program director for The Nature Conservancy Jon Kachmar. Mr. Kachmar said the Tisbury Great Pond was the ideal location due to its salinity and the presence of wild oysters in the pond.
“Tisbury Great Pond jumped out [for the project site],” he said.“Historically there are oysters in the pond, we know there was eel grass in the pond that seems to have vanished, we know that the nutrients in the pond are probably increasing like all coastal waters.”
He continued: “We focused on Tisbury Great Pond because of the stewardship that has already gone on between the two towns and it’s a place that seemed like it needed some restoration for the sake of ecology and the fishery, which is the intent of the project,” he said. The Nature Conservancy tried to start the project two years ago but it faltered due to lack of funding. Eventually using private donations and some nonprofit grant money, the $60,000 project became a reality.
The project has the backing of conservation commissions in West Tisbury and Chilmark, the state Division of Marine Fisheries and U.S. Army Corps of Engineers. A dive survey required by the DMF was completed last week. Divers found about four inches of mud in the reef area, which shows that the area has been unable to support shellfish for some time, Mr. Scheffer said.
But beneath the mud the divers found dead shells.
“That means at one time there were oysters in this area,” Mr. Scheffer said “A hundred and fifty yards to the south there’s a reef with the same type of bottom and same type of environment around it that’s naturally occurring. They dug down a foot and it was all shell, which means it’s been there for some time,” he added.
The information is important for the reef project, Mr. Scheffer said.
“We know that the [test] area is not going to get too anoxic for the oysters to survive. And it’s good to know that there’s potential, that we’re not going to be doing this all for nothing,” he said.
Mr. Scheffer slowed down and threw a drag over the side in a spot where a small project to grow oysters using shell culch was tried a few years ago.
“If I hit the spot where we put the shell in before, you can see how many oysters we can create,” he said. He throttled forward slightly, came to a stop, pulled up the drag and dumped the contents on the culling board.
Dozens of oysters were attached to the shells. “They’re getting so big now,” he said. “All they need is a place to set. Timing is critical when we’re doing these projects. We’re trying to get the shell in almost a week to two weeks before they set so it has a little time to be in the water. They seem to like that better, I guess.”
Most of the center of the pond is considered a dead zone for shellfish, Mr. Scheffer said. If the one-acre oyster reef proves successful, the project could expand to other areas of the pond.
“My job ultimately is to create more shellfish for people to go fish for,” Mr. Scheffer said. “This could be a stepping stone for other towns to do restoration work.”
While there is thick algae in some of the coves, Mr. Scheffer said the main part of the pond appears to have good water quality.
“There’s not as much algae as there used to be,” he said. “I think the pond hasn’t reached its capacity by any means as far as how much shellfish it can produce.”