When heavy rain overloads New Bedford's old sewers, Massachusetts closes Dale Leavitt's oyster farm across the harbor. This year a state sampler and a harbor full of red dye have been working out where that closed zone should end. Some of what they learn matters within days, some won't arrive until 2027, and the fix for the pipes runs on a schedule measured in decades.
The way out to West Island Oysters goes under a road. In reporting published in September, Jennette Barnes of CAI and WSHU found Dale Leavitt in a small electric boat, passing through a culvert beneath the West Island causeway in Fairhaven, Massachusetts. He was carrying visitors from a shellfish conference out to his farm's work barge and the floating cages where his oysters grow. Fairhaven sits across the harbor from New Bedford, and the farm Leavitt co-owns spreads over 47 acres of Nasketucket Bay.
Leavitt told Barnes what the closures do to the business:
"I mean, when you're closed 50% of the year to being able to sell oysters, it sort of impacts your cash flow."
He didn't say which year he meant, but the most recent full count fits. In January 2025, The New Bedford Light reported that West Island and a neighboring farm had lost more than 180 days to emergency closures in 2024, about half the calendar. The same story said Leavitt had planned to expand before the closures stacked up.
Leavitt, a retired marine scientist from Roger Williams University, understands the reasons better than most of the people these closures shut down. He knows what's in the water after a storm and why the state closes it. He still has to get the business through the months when he can't sell.
A farm that keeps working when it can't sell
A closed day doesn't pause the farm. The oysters are alive in the bay, filtering water, growing, and holding on to whatever that water carries. The crew still has gear to tend and animals to look after. What stops is selling: nothing harvested from a closed area can go to market.
Leavitt hasn't made his prices, weekly volume or buyers public, so there's no honest way to put a dollar figure on his lost days.
For a rough sense of how oyster money moves: in June, growers in Plymouth were getting about 55 cents an oyster from wholesale buyers at the dock, Peter Zheutlin reported in the Plymouth Independent. That figure comes from one harbor in one month, so treat it as a guide. It shows the shape of the income, which arrives in small amounts repeated many thousands of times. All of it stops on the morning a closure notice goes up, while bills like payroll keep coming.
The damage also lasts longer than the closure. NOAA, the federal ocean agency, has described what delays do to shellfish farms. It was writing about closures caused by toxic algae, but the mechanics apply to any forced pause. Oysters keep growing past the size buyers asked for. Promised deliveries fall through. Unsold oysters take up cage space that next season's young oysters need.
Size matters more than it might seem. A NOAA market study found that raw bars and high-end restaurants now want small, uniform oysters, about three inches long. An oyster held in a closed bay a few extra weeks can grow out of that window. Nobody has published how often that has happened at West Island, but it's one way a closed week can reach into next year.
Growers have been working around a problem they can't fix. The Light reported in early 2025 that some had picked up small plots in a part of Mattapoisett that closes less often, so they could move oysters there ahead of an expected closure. Scott Soares, who farms in Dartmouth, was weighing a shellfish dealer's license, which would let him keep selling oysters he'd harvested and stored before a closure hit. Mike Ward had planned to sell his Nasketucket farm and retire, and the closures upended that.
Those were their plans in early 2025. How often anyone has used the Mattapoisett plots since, and how the other plans turned out, hasn't been reported.
Why rain closes the bay
New Bedford, like many older Northeast cities, has stretches where a single set of pipes carries both sewage from homes and rainwater off the streets. In a big storm, more water arrives than the treatment plant can handle. The system was built with release points so the excess spills into the harbor instead of backing up into basements and roads. Those spills are called combined sewer overflows.
Oysters are eaten raw and whole, and they concentrate what they filter. Sewage carries viruses that make people sick. So when an overflow happens, the Division of Marine Fisheries, the state agency responsible for shellfish safety, closes the surrounding water for 21 days by default. How big the closed area is depends on how much spilled, how dirty it was, how much clean seawater it takes to dilute it, and how the tides and wind carry it.
There's a quicker way back. After seven days, state staff can collect oysters from the closed water and test them for male-specific coliphage, a virus that infects gut bacteria and shows up reliably in sewage. Because it's easy to measure, it stands in for the harder-to-detect viruses that actually cause illness. If results come in at or below the federal limit of 50 per 100 grams of shellfish, the state may reopen early. Somebody at the agency still has to make that call; day eight doesn't reopen anything by itself.
For a farm like West Island, the difference between an early reopening and the full 21 days can be close to two weeks of sales from a single spill. That testing kept 2024 from being worse. The agency counted 20 sewage-overflow closures in parts of Buzzards Bay that year, costing 210 harvest days altogether, and says testing ended every one of them before the full 21 days ran out.
As for where I stand: the closure line exists so that someone eating a raw oyster in a restaurant doesn't get sick from New Bedford's sewage. None of the growers quoted in the coverage I've read want it gone. What they're pushing on is whether the line sits in the right place, whether it lasts the right number of days, and who gathers the facts that decide both. Those are fair questions to put to a system they didn't build and can't repair.
This fall, notice by notice
The state posts every closure and reopening as a dated notice. Reading them in order is about as close as an outsider can get to a grower's fall. Nasketucket Bay carries the state code BB21.
| Date | What the state did |
|---|---|
| Sept. 25 | Precautionary closure across most of Buzzards Bay for heavy rain |
| Sept. 28, 9 a.m. | Sewage-overflow closure covering Nasketucket Bay, after spills from rain Sept. 25–28 |
| Oct. 7, noon | Both closures lifted for Nasketucket Bay and neighbors |
| Oct. 12, 8 a.m. | Closed again after spills from rain Oct. 11–12 |
| Oct. 20, 9 a.m. | Reopened for oysters only |
By my count, between September 25 and October 20 the bay was open for just under five days, from noon on October 7 to 8 a.m. on October 12.
That may not match West Island's experience exactly. The state's map of the bay labels most of it "conditionally approved," with a few small pieces classified differently, and it doesn't show where the farm sits. "Conditionally approved" means the water is open in ordinary weather, but a written management plan shuts it automatically when certain triggers occur, such as heavy rain or a sewage malfunction. Lifting the October emergency orders put the bay back under that plan; it didn't loosen anything. And no 2026 total has been published for the farm, so there's no way yet to tell whether this year is running worse than 2024.
The man at the pipe
Much of what decides the closure line happens where growers can't see it. Barnes reported on Matt Camisa of the Division of Marine Fisheries, who collects water at a sewage outfall, the pipe mouth where overflow enters the harbor, sometimes in the middle of the night. His kit is a sampling pole, bottles, a bucket and a cooler. At a conference in April, he said he sampled every 15 minutes.
The frequency matters because of how a closure gets sized. The state needs to know how contaminated the overflow is, and without measurements across a whole storm, it has to plug in an assumed number. As Barnes described the goal, sampling every 10 to 15 minutes from the first spill to the last would let him calculate an actual average for that event. If the average comes in lower than the assumption, less seawater is needed to dilute it, and the closed area can shrink.
It can go the other way, too. His numbers could show the overflow is dirtier than assumed, which would push the line outward. The published reporting doesn't name his pipe, share his results, or show that any line has moved yet. His work is also separate from the seven-day oyster tests: he measures what comes out of the pipe, and those tests measure what ended up in the shellfish.
This is what growers asked for. Barnes reported that they want more frequent testing, better models of how bacteria spread, and action to stop the overflows.
A red harbor, with answers in 2027
The work most likely to redraw part of the map near New Bedford happened in mid-September, just before the storms. On September 12, researchers released red dye where the city's sewage treatment plant discharges and tracked where it spread through September 17, Brooke Kushwaha reported for the Light. The harbor turned red. Leavitt and Soares supplied oysters for the research, which the state ran with the FDA, the city, university scientists and industry members.
I keep thinking about the growers handing over their own oysters to help test the rules that close them. The study itself is narrower than the rain closures, though. The plant releases treated wastewater every day, and the state keeps a permanent closed zone around that discharge. The study's stated goals are to see where that treated water actually travels, check whether the permanent zone is the right size, and improve how the state responds when the plant malfunctions or raw sewage escapes. That overlaps with the rain closures that hit Nasketucket Bay this fall, but it's a different question.
According to draft minutes from a November 2025 meeting of the state's Shellfish Advisory Panel, outside reviewers found the agency's computer model of water movement fit for its purpose, while recommending more checks against real conditions and better handling of uncertainty. Tracking dye through the actual harbor is one of the most direct checks available.
Final results are expected in 2027, with no month given. Nobody has promised the zone will shrink, that closures will get shorter, or that West Island will gain a single day. The findings could hold the line where it is, pull it back, or push it farther out toward the farms.
The decades-long fix for the pipes
Fewer sewage closures means fewer sewage spills, and that's the slowest work of all. New Bedford's 2017 draft plan for controlling overflows laid out construction through 2036. Separating sewer and storm pipes near St. Luke's Hospital was slotted for 2035 and 2036. A storage tank for an area the plan calls the "Ponding Area" had only its design and permitting scheduled, in 2036. The plan expected some spending after that.
The city's 2025 hazard mitigation plan refers to a January 2025 update of the project list. No official document I read names a year when New Bedford's overflows stop.
Then there's the rain. An overflow happens when a storm sends more water into the pipes than they can carry, and the state transportation department, in its flood risk assessment, reports that "over the past few decades, Massachusetts has experienced significant increases in heavy precipitation events and flooding." That's a statewide finding. None of the sources connects a particular New Bedford overflow, or any closure this fall, to that trend.
One more complication: local reporting indicates that part of the rise in closures comes from better reporting. The state now hears about more of the spills that were already happening, so some of the closures growers are absorbing reflect a more complete count.
Betting on three clocks
Leavitt's remark about cash flow spans all three of these timelines. In the short run there's a spill, a seven-day wait, oyster tests and a reopening notice, a cycle that can repeat several times in one autumn. Next year brings the dye study, which might redraw the zone near the harbor or confirm it. Over decades there are pipes, tanks and city budgets. A grower deciding whether to expand, sell or hold steady is making a bet that touches all three, and only the first moves fast enough to show up in a season's books.
The workarounds on record are the ones growers have described: moving oysters to steadier water, looking at licenses that let them sell from storage, asking for more sampling, and supplying their own oysters for the dye study.
Planning around all three timelines is harder. At minimum, a grower would want the written plan that decides when their water closes and a map showing where their lease sits against the line. For Nasketucket Bay, I couldn't readily find either in what the state posts publicly.
The latest notice on the state's list as this issue went to press, posted October 20, reopened Nasketucket Bay for oysters under its conditional plan. The next rain heavy enough to overload New Bedford's pipes will close it again.
