Over the next year, a million tiny pioneers will arrive at Sengekontacket Pond.
Simply by growing from the size of a pencil eraser to a full three inches, a million oysters are the key part of a project launched by Oak Bluffs and Edgartown to cultivate the shellfish in Sengekontacket, which has been found to have nitrogen levels well above acceptable limits. The oyster project, if it is successful, could be a win-win for those who love the pond and those who love to eat shellfish: the oysters, which naturally filter nitrogen out of the water, will clean the pond. When fully grown, the oysters will be planted in the pond to be harvested and eaten.
A draft report states that failure to reduce the nitrogen level could result in the loss of eelgrass, a higher frequency of undesirable decreases in dissolved oxygen concentrations, fish kills, “widespread occurrence of unpleasant odors and visible scum,” and even a complete loss of macroinvertebrates that live on the pond floor. Oysters feed off algae and take nitrogen with them when they are removed from the water. About 10,000 active, grazing oysters will remove the nitrogen output from a single household.
The project, cheaper than alternative remediation like sewering, hinges on the success of growing oysters in Sengekontacket — particularly Major’s Cove, which was identified as one of the areas with the most nitrogen. Parts of Major’s Cove are closed to shellfishing because of unsafe levels of bacteria
To test the oysters’ prospects, shellfisherman and project steward Jack Blake placed a cage of oysters at the bottom of the pond between Felix Neck and Pecoy Point last November. Wednesday was the big reveal — if all went right, the cage of oysters had been growing all the while.
“If half of them are dead, we’re in trouble,” Mr. Blake said, using a winch to hoist a cage filled with bags of oysters from the bottom of eight feet of water and onto his boat. The cage was covered in mud and crabs. A bag was selected and dumped onto a console on the boat. Good news would be live oysters with about three quarters of an inch of new shell.
Out came dozens of year-old oysters, most alive and healthy, despite the presence of some sponge and white worms. Things were looking good, although “I suspect the town is going to have to buy themselves a pressure washer,” Mr. Blake said, eyeing the muddy mess as it was lowered back into the water for the oysters to grow some more.
Mr. Blake is more familiar with the ocean-fed waters of Katama Bay, where he operates his Sweetneck oyster farm. The plan to grow oysters in the less familiar waters of Sengekontacket started with the report that the pond was endangered by high nitrogen levels. “I’m thinking, it sounds like we need all hands on deck,” Mr. Blake recalled.
As a member of the Edgartown shellfish committee, Mr. Blake turned to that group to talk about a plan. They thought they could help in the way they know how — through shellfish. “That’s our way of contributing,” Mr. Blake said.
The shellfish committee and shellfish constable Paul Bagnall wrote up a plan to take to town meeting, seeking $48,500 for a two-year program to grow a half million oysters, with the money to come from free cash. Oak Bluffs, which shares the pond with Edgartown, signed on as well, with their proposal to be funded by Community Preservation Act money. Both towns approved the proposals, but the Oak Bluffs funding will not come through until July 1, too late for this growing season. As a result, the Oak Bluffs part of the project will start next spring.
The bulk of the money for the project will be needed in the first year for equipment. Mr. Blake designed and oversaw construction of a new, smaller upweller that would work in the shallow pond waters. The upweller, a floating wood structure, will house the baby oysters when they are small, and is designed so water will flow through the wooden structure, spurring oyster growth.
Deputy shellfish wardens Warren Gaines and Robert Morrison worked around the clock on the project, as did summer deputy Peter Jackson, who came on board early this year.
Mr. Blake said future expenses will be lower once the equipment is in place, with half a million oysters costing about $4,000.
The upweller, painted a primary blue on the bottom with a gray top, went into the water on Wednesday, escorted by the deputy constables, and Mr. Blake and his wife Sue, to a spot south of Sarson’s Island. “It looks small out there, Jack,” Mr. Gaines noted after affixing the upweller to a blue buoy.
The upweller was fitted with three “daddy long legs” contraptions with flexible wires that bend and wave in the wind meant to deter cormorants from making the oyster nursery a new perch. “I don’t want these birds to get bad habits,” Mr. Blake said. At night, there will be a solar-powered blinking light on the upweller to warn night water traffic.
Mr. Bagnall is scheduled to drive to Maine this weekend to pick up oyster seed from Muscongus Bay oyster hatchery. He’ll return with seed for Sengekontacket as well as several Katama Bay oyster farms. All told, he’ll have about six million oysters for company on the trip back. He said he hopes to have the oysters in the pond by Monday afternoon.
The Sengekontacket oysters will spend their first seven weeks or so in the upweller, growing larger in the warm summer water. But they’ll soon outgrow their nursery and get kicked out of the nest to small mesh bags in cages. They will spend about a year in Major’s Cove. Next summer, the first batch of oysters will be planted in the sand, where they can be harvested by people with recreational shellfishing licenses.
Despite Mr. Blake’s optimism, there are some hazards. It’s possible the pond doesn’t have the right food for the babies, Mr. Blake said. He’ll know quickly and, if that’s the case, take them to Katama. “We’re not going to let them die,” he said.
The oysters take on the taste of the food they eat, too, and so the taste of the Sengekontacket oysters is also an unknown.
Regardless of taste, though, the oysters should be doing their part to clean the pond when they are harvested, one small part of a larger effort. “The oysters are very good filter feeders,” Oak Bluffs shellfish constable David Grunden said.
“Putting the funding into the oysters isn’t going to solve all the nitrogen problems, but it should help,” he said, adding that there’s “only one very expensive silver bullet — sewering.” That option is costly compared to the oyster project, he said.
“In two or three years there’ll be a legal-sized harvest,” Mr. Grunden said. “Maybe the town will sell more shellfishing licenses.”
“[The oyster project] in itself is not going to be a cure for Sengekontacket, but it’s one piece of the puzzle,” Mr. Bagnall said, adding that some of the science of the direct impact on the pond hasn’t been figured out. But he emphasized that, regardless, there will be half a million oysters available for family harvest, “and that number was good enough for town meeting.”
Mr. Bagnall had high praise for the smaller upweller and for Mr. Blake. “We wouldn’t have gotten it up and going this year without him.”
“I think this is going to be a test to see how it works,” said Rick Karney, the executive director of the Martha’s Vineyard Shellfish Group. “This could possibly be a way of getting oysters into the ponds in public beds and getting a lot of the habitat and water purification services from them.
“This is a first. We’re going to watch it and see how it works,” he said, adding that the project could be replicated in other ponds if successful.
Kris Vrooman, president of the Friends of Sengekontacket, said the oyster project is just one piece of the effort to reduce nitrogen in the pond. The group is working on education programs in the community, she said, including carry-in/carry-out campaigns, “Saturdays on Sengie,” a free educational program for children and their parents, and spreading the word to residents that nitrogen is the problem.
“I think it’s just one part of trying to lower nitrogen,” she said. “We’re just excited about it. It’s at least one way we can decrease the nitrogen in the pond.”
“I think we need to give it a shot,” she said. “It’s an opportunity to learn more.
“We’ve just got to take care of the pond. We’re the stewards of the pond.”