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The tidal waters of Maine tell stories that go back thousands of years. Along the Damariscotta River, a short tidal river carved out by retreating glaciers at the end of the last Ice Age, the story of the wild oyster is told through heaps of bleached-white oyster shells discarded by prehistoric people The Whaleback Shell Midden, in the town of Damariscotta, is one of the most remarkable: 1,000 feet wide and 30 feet tall, it is a tale of bygone abundance.
While wild oysters were an important part of an Indigenous diet in what is now Maine, by the 1900s they had all but disappeared. Most people considered them functionally extinct, in fact, until this spring, when researchers from the University of Maine published a study confirming their return, often in close proximity to the oyster farms that have populated the waterfront over the last few decades.
“When we think about the emergence of wild oysters, it’s bringing back a part of the ecosystem that has been a part of who we are as people in this place, part of Indigenous people’s connections to this place,” says Heather Leslie, a marine conservation scientist who took part in the study. “It foregrounds the question of not just restoring the non-human parts of the ecosystem but also enabling the Native people to reconnect with coastal ecosystems.”
“When we think about the emergence of wild oysters, it’s bringing back a part of the ecosystem that has been a part of who we are as people in this place.”
Oysters sequester carbon and help filter sea water, making them one of nature’s most beneficial bivalves. Their appearance may be a boon for the ecosystem of the Damariscotta River and the local economy. But the rediscovery isn’t all good news: It is also a sign of warming waters that can imperil other species.
As filter feeders, oysters help to remove natural and unnatural contaminants, such as algae and pollutants, from the water. The state of Maine has encouraged oyster farming as a way to maintain clean waterways, which are at higher risk of harmful algal blooms as waters warm.
Those warming waters are not only more prone to contaminants, they are also becoming too hot for Maine’s most iconic harvest, the lobster, whose migration north will likely upset a longstanding way of life on the Maine coast.
A Comeback Story
Oyster industry experts have proposed many reasons for the disappearance of Maine’s wild oysters. One hypothesis is that the Gulf Stream—a warm current in the North Atlantic that operates like a river within an ocean—shifted gradually in the late 1800s, causing the Gulf of Maine to cool. The change killed off oysters, which prefer slightly warmer temperatures.
Additionally, in the late 1800s, oysters had a heyday of popularity among European settlers—not unlike the booming appetite for them today. The craze for oysters subsided when the bivalve population was severely depleted.
The owner of Maine’s Pemaquid Oyster Company and local historian, Smokey McKeen, has farmed oysters in the Damariscotta River since the 1980s. (Photo credit: Kayli McKeen)
Another leading cause of oyster decline was the rise of the New England state’s sawmills.
“The upper Damariscotta River had 20 shipyards,” explains Smokey McKeen, local historian and co-founder of the Pemaquid Oyster Company. “What were they going to do with the sawdust? Well, why not just dump it in the river?”
Oysters feed on ambient algae, plankton, and bacteria as they draw in the water around them. They can help keep estuaries clear and healthy by filtering out bacteria, but too much sediment, such as sawdust, can kill them.
In the mid 1980s, long after the sawdust had settled, three oyster farms opened in relatively quick succession in the Damariscotta River, bringing oysters back to Maine’s mid-coast waters. One of these was the Pemaquid Oyster Company, which McKeen established with partners Carter Newell and Dave Barry. The company still grows and sells oysters today.
While a few oyster farmers grow their oysters on the flats of tidal seabeds, most raise the bivalves in submerged cages that have holes to allow water, which contains everything an oyster needs to eat, to flow in and out.
Wild oysters grow on rocks at the tide line on Maine’s coast. (Photo credit: Sarah Risley / University of Maine Darling Center)
Until that point, most oyster farms in Maine had used Belon oysters (Ostrea edulis), a popular French type with a metallic taste that McKeen describes as “like sucking on a pocket full of coins.” The three new Damariscotta River farms were inspired by Herb Hidju, a college professor at the University of Maine, who suggested farming with Eastern oysters (Crassostrea virginica), which were once native in the region and have the sweet, rich and briny taste that oyster lovers go crazy for.
At the fledgling Pemaquid Oyster Company, the Eastern species thrived in the nutrient-rich waters of the Damariscotta River. “All the oysters grew,” remembers McKeen, “and it turned out everybody liked them, and we thought, ‘Huh, well, maybe this is more than just something to do on a Saturday morning.’ It became a thing, and it really ballooned.”
“It turned out everybody liked them, and we thought, ‘Huh, well, maybe this is more than just something to do on a Saturday morning.’”
Oyster farming grew in popularity over the ensuing decades in Maine, and truly started to boom in the 2010s. The Gulf of Maine is warming faster than any other ocean body on the planet, creating ideal conditions for oysters.
Growing oysters is providing new opportunities on Maine’s working waterfront as the warmer temperatures push lobsters out toward cooler waters. Maine’s lobster fishery produced more than $725 million in 2021 and provided tens of thousands of jobs for Mainers. In the past four years, however, that revenue has decreased to $528 million, and in 2024, lobster harvests in the state hit a 15-year low.
A 2025 NOAA study of farmed oysters in South Carolina found that an oyster farm of 1 million oysters removed the equivalent of around 300 pounds of nitrogen from the water. State and federal dollars now encourage oyster farms, and programs like Maine Sea Grant see oysters as a climate savior and an alternative to diminishing resources like lobster.
Aquaculture is now an integral part of Maine’s working waterfront, with more than 150 oyster farms along the coast.
Breaking Into the Wild
As Mainers started to farm oysters, they noticed an unintended consequence: Wild oysters began to appear. The new wild populations tend to be near oyster farms and of the same variety thatthe farms are cultivating.
The farmed oysters are not “escaping,” though; they are spawning, in a process often triggered by warm water temperatures. Male and female oysters release eggs and sperm into the ocean, where they create larvae that drifts around on the current in search of a suitable substrate.
The “wilds” frequently attach themselves to rocks along the tide line, sometimes drifting many yards away from the oyster farms that spawned them. Further spawning by the wild oysters can lead to wild oyster populations thriving in intertidal zones even farther away.
These wild oysters are harvested by people holding shellfishing licenses, both commercial and recreational. They currently supply the small but growing market for wild oysters, selling to a few restaurants, seafood markets, and to existing oyster farms that make them available to the public.
Pickers can be salty characters, some of the last true foragers of the coast. They spend long days on the mud flats at low tide, bent over holes that they dig with specialized rakes, seeking out soft-shell clams, the most commonly harvested shellfish in Maine. They often gather wild oysters too; the stationary creatures can be a relief to find as they only need to be pried off the rocks exposed at low tide, rather than dug out of the thick mud.
Once seed oysters reach a certain size, the staff at Pemaquid Oyster Company move them to floating nursery bags. When the oyster seeds reach 50 mm, they are bottom-planted in the company’s large open-water lease and harvested one to two years later. Here, the Pemaquid crew heads out for the first fall bottom planting of 2023. (Photo credit: Pemaquid Oyster Company)
These breakout oysters are more than a food source; they’re an ecological signal. And researchers want to understand what their return means.
In 2023 and 2024, University of Maine marine science PhD candidate Sarah Risley, along with professor Leslie, conducted surveys of intertidal zones, counting and measuring oysters to understand the baseline population. And in the spring of 2025, they published the study confirming the increasing presence of wild oysters in the Damariscotta River.
One of Risley’s areas of interest is whether these oysters, most likely spawned from farmed oyster cages, can create their own reproducing populations. “We are thinking about how the connection between the two populations might play into oyster restoration,” explains Risley. “Where the project is moving now is thinking about how we take this information about emerging populations and put it to use creating sustaining populations.”
Farmed oysters come in two varieties: Triploids are essentially sterile, and diploids can reproduce. The farmers on the Damariscotta River largely work with diploids, but there are still questions as to how hardy and reproductive a population “going native” might be. The work that the University of Maine study has begun will inform shellfish harvesters and ecologists on how best to support a wild oyster population in the Damariscotta, where their emergence is in many ways a return to the natural ecosystem of the river.
Still, shellfish harvesters have raised concerns about the possibility of wild oysters outcompeting the decreasing population of soft-shell clams for resources.
Others note that the clam population’s decline had been observedfor many years before wild oysters began appearing in the river. Also, new invasive species such as the aggressive European green crab, which eats the clams and can erode the ecosystem they need to survive, are a more significant threat.
“They may be looking for a correlation where there are more oysters,” explains Jacqueline Clarke, a seafood expert and co-founder of Nor’Easter Oyster Company, in South Bristol, Maine. “But there are so many other factors, like water temperatures, green crabs—all that fun stuff.”
The Next Chapter
Maine’s accidental oyster rewilding may also be a business opportunity. One of the most successful oyster farms in the state is Glidden Point Oysters which, like Pemaquid Oyster Company, farms its bivalves in the nutrient-rich waters of the Damariscotta River.
The farmers at Glidden Point not only sell their own oysters; they also wholesale oysters from other farms in Maine and ship them around the country—and, when they can source enough from shellfish harvesters, they sell wild oysters too.
“I love the wilds,” says Ryan McPherson, owner of Glidden Point. Like all oysters, the taste of a wild oyster is informed by place. Because they grow in the intertidal areas, they’re usually overhung by rockweed (a type of seaweed), and sometimes pick up its briny flavor. “They have more of a toothiness to them,” says Risley.
Oyster farmers pull cages from the dock at Glidden Point on the Damariscotta River. The farm stores oysters in the water to maintain their freshness. (Photo credit: Glidden Point Oysters)
Still, selling wild oysters has its own challenges. Wild oysters vary in appearance, without the deep cup and correspondingly plump meat typical of farmed oysters. “They’re variable sizes and they’re inconsistent shapes,” says McPherson. “And they’re harder to shuck, compared to farmed oysters. You have to find somebody who really wants them, wants to tell their story at their restaurant.”
For anyone interested in tasting a wild oyster, the process is not always as simple as heading to your local Maine oyster bar. Wild Damariscotta oysters can be ordered online through Glidden Point Oyster Company, which sources them from Maine shellfish harvesters, but they are harder to find on menus than the farmed varieties.
Jacqueline Clarke points out that while wild oysters have been missing from the Maine coast for many decades, they have been part of the state’s coastline longer than they’ve been absent. “They’ve been around for thousands upon thousands of years, everywhere, up and down the coast, and definitely in the Damariscotta,” she says.
To forage or eat a wild oyster along the mineral-rich waters of the Damariscotta is to bridge the centuries, to connect Maine’s ancient past with its present. In that sense, the new population is not just a harbinger of change, but a symbol of resilience.
The post Wild Oysters Make a Comeback in Maine appeared first on Civil Eats.
