Lagoon struggling water quality behind Tisbury shellfish regs

Tisbury shellfishermen say a lack of oxygen at the Lagoon floor is threatening their viability.


Jeffrey Canha was the first Tisbury resident to get an aquaculture license for the Lagoon when the town passed its first set of regulations in 2019. 

He had high hopes for the industry, investing his savings into shellfish seed and an operation on the Lagoon side of Beach Road: a shipping container serving as his humble headquarters, dock space provided courtesy of the Packer family, a small boat, oyster cages, and a whole slew of other equipment.

After more than a year of “pushing papers,” Canha got his first oyster seed into the water in 2021, starting Husselton Head Oysters. He started slow, knowing that he was new to the industry, and bought a relatively small amount of seed to get going.

“​​There are rookie mistakes,” Canha said. “I didn’t want to order too much.” 

In that first year, the mortality rate was substantial. Close to 90 percent of his oysters died. The next year, still confused by what had happened, he ordered more to make up for the lost year. But the mortality rate was still close to 80 percent.

Scraping together what seed he had saved from the previous years, he went for round three this past spring. And it was then that he understood what was wrong. He was moving his seed from the bottom of the Lagoon when he noticed his oysters were bleached white. The bleaching, he said, was an indication that they weren’t getting the oxygen they needed.

Canha — and others in the industry — say that poor water quality of the Lagoon is what is leading to the die-offs. The technical term is hypoxia.

As Canha describes it, algae that bloom in the early summer in the Tisbury water body proliferate and grow in June. Eventually, the algae dies off, and then sinks to the sea floor around July, clouding up the water almost like a layer of mud. 

Testing confirmed his suspicions: Through the help of the Cape Cod Cooperative Extension, he found almost no dissolved oxygen at the bottom of the Lagoon near his farm, likely choked out by algae blooms. 

Last year, Canha tried a Hail Mary, asking the select board for permission to move his lease to an area closer to the water’s surface within the Lagoon, so the shellfish wouldn’t be as deep. But the select board denied the request. Some concerns listed included interference with vessel access and recreational activities.

Now Canha is close to cutting his losses and throwing in the towel. 

But a new proposal before the town’s select board — the first time the regulations would be changed since going into effect in 2019 — has offered him and others working in the Lagoon some hope.

The proposed regulations include a number of changes, like relieving aquaculture farmers of an annual mooring fee, and streamlining the process required to get a license. But the major part of the regulation change would allow Canha and others to grow their oysters at the surface of the Lagoon, rather than forcing them to the bottom. 

Canha is considering a system that would use floating cages or bags that would sit on the surface, if the regulations pass. While Island towns technically don’t allow the floating systems, the practice is commonplace across the Cape, where aquaculture is a large industry — and especially where algae blooms cut off oxygen at the sea floor.

“If these regulations don’t pass, there’s absolutely no path forward for aquaculture in Tisbury,” Canha said of the proposal going before the select board next week. “I have $200,000 dollars of sunken investment, of my hard-earned life savings.”

Canha isn’t the only one in support. The town’s natural resources advisory committee recently supported the proposed regulation changes unanimously.

“If it helps the aquaculture farmers to produce a better product, fine,” chairman of the advisory committee Tom Robinson told The Times. Robinson said he doesn’t expect the regulations to make much of a difference to anyone other than the farmers.

But there have been concerns in the past about shellfish farms posing a risk to navigation and other recreational activities, like fishing and swimming, as was voiced against Canha’s relocation application before the board last year. Several letters were sent to the town from nearby homeowners, voicing concerns.

The Lagoon Pond Association, a group that aims to protect and preserve the body of water, issued a statement to The Times this week about the proposed changes, saying they have been paying close attention to what is being proposed.

“The health and welfare of Lagoon Pond is our primary concern. If we can arrive at regulations that satisfy the state and are supportive of the shellfish constables and the aquaculture farmers, we would be delighted,” the statement read. “Ensuring that all of us can safely utilize the waters for a variety of commercial and recreational activities in harmony is the goal for all of us.”

Asked about potential impacts to navigation in the Lagoon, Robinson with the advisory committee said that cages floating at the surface don’t make a difference, compared with floating at the bottom. Boats will still have to avoid the lease areas in order to avoid tangling their propellers, whether the oyster cages are floating near the surface or sunk to the bottom.

In writing comments to the select board over the proposed regulations, Danielle Ewart noted that if floating cages were approved, she suggested requiring the use of bird deterrents. “Bird droppings are one of the biggest issues with floating ‘surface’ gear, as it is far more popular for birds to roost on than any other gear type,” she wrote to the board. Bird droppings can be problematic for water quality, but deterrents can keep the birds away.

Aquaculture farmer Noah Mayrand, who also sits on the advisory committee, has an oyster farm in the Lagoon not far from Canha’s. He also has concerns about the future of the industry in Tisbury if the regulations aren’t changed. His shellfish have experienced the same die-off at the bottom of the Lagoon during the summer months. While he has reached a special agreement with the select board to keep his shellfish near the surface of the water, he said that there is ambiguity in the town’s original regulations, and it’s leading to consternation with town officials. The ambiguity has led to scuffles with the town’s shellfish constable, and has been a major hindrance for his business.

Mayrand is also a big supporter of dropping mooring fees, and making it easier for local residents to get into the industry. Part of the proposed regulation changes would cut down on the time it takes to receive the right approvals from the town; he said it’s already complex getting the green light from multiple state and federal agencies.

Right now, he said, it feels like Tisbury is too restrictive, rather than encouraging the industry to grow. Because oysters are known to help reduce pollution in water bodies, the town is gaining from having the farms in the Lagoon. The Massachusetts Estuaries Project and other studies have found that the Lagoon has problematic water quality because of nutrient loading, and not very much flushing into the ocean. That can lead to problematic algae blooms.

And as proven in Edgartown and Chilmark, farming can provide a good profession for locals. But Mayrand says it has its difficulties. During the recent storms, he nearly lost his boat. And it’s a lot of risk buying thousands of oyster seeds and starting in a new location like the Lagoon.

“It’s a big gamble against Mother Nature, so the town has to support it,” Mayrand said. “We are helping to clean the water. This is a massive industry that deserves to be treated with support.” 

The Tisbury select board is scheduled to have a public hearing on the regulations on Feb. 7.


  1. I have an idea. Why not put a tax on Vineyard homeowners and use the money to make it easier for more people to live here?

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