Oyster Reef Restoration in New York Relies on Key Ingredient

Expanding shell recycling will benefit species, habitats, and shorelines, experts say

Oyster Reef Restoration in New York Relies on Key Ingredient
Large metal cages full of recycled oyster shells are prepared for restoration sites in New York Harbor.
Large metal cages full of recycled oyster shells are prepared for restoration sites in New York Harbor.
Billion Oyster Project

New York, like many coastal states, is working to restore once-prominent native oyster reefs along its  shoreline but faces a challenge finding enough shells to serve as reef foundations. To learn more about the state’s shell recycling efforts, The Pew Charitable Trusts spoke with Maddy Wachtel, deputy director of the Billion Oyster Project in New York City, and Maureen Dunn, a water quality scientist and director of Seatuck Environmental Association’s Half Shells for Habitat oyster shell recovery program on Long Island.

This interview has been edited for clarity and length.

Q: Tell us about the history of oysters in New York City and on Long Island.

Wachtel: Before New York City was known as the Big Apple, it was called the Big Oyster. It was the oyster capital of the world. Eating oysters was a culinary treat for rich and poor alike, and shells paved Pearl Street. In the 1600s, over 200,000 acres of oyster reefs served as incredible habitat for hundreds of marine species in New York Harbor. Both wild and farmed oysters were harvested from these waters, but the last of the commercial oyster farms closed in the 1920s because of pollution. Even before then, wild native oysters had gone virtually extinct in the harbor because of overharvesting, dredging, and pollution. Now New York Harbor oysters aren’t edible because of pollution and sewage overflows into the water during rainstorms.

Dunn: On Long Island at least 6,000 years ago, Native Americans were eating oysters from vast reefs along our shores. In the 1800s, oysters from Blue Point on the south shore were prized as among the finest in the world for the flavor imparted by the clean waters of the Great South Bay. But overfishing, shellfish disease, and habitat destruction also decimated wild oysters here. Unlike clams, that live in the sand and mud, oysters form reef structures as hard as cement. To harvest a wild oyster, you have to chop apart the reef. And if you don’t build that reef back, your oyster population cannot sustain itself.

Q: Why do oysters need reefs, and why are shells so vital to them?

Wachtel: When oysters reproduce, their babies—larval oysters—are free-swimming for the first few weeks. Once they settle onto a hard surface, like shells or an existing reef, they won’t move again for the rest of their lives. If larvae fall onto a soft and silty bottom like the one in New York Harbor, they can become covered and die without access to oxygen and food.

Dunn: People have experimented with other hard substrates to start reefs, like cement and even porcelain toilets, but what a larval oyster (also called spat) likes most is another oyster shell to settle on. Because there are so few adult oysters here, adding cured shells to tanks of larval oysters kick-starts the process of reef growth. Once they’ve attached and grown big enough, the spat-covered shells are transplanted to a wild reef.

Q: Describe how your shell recycling program works.

Wachtel: On a typical day, a truck would leave from the Lobster Place, a seafood wholesaler we partner with in the Bronx, collect shells from 20 to 25 restaurants in Manhattan and Brooklyn, and deliver them to our dumpsters in Greenpoint, Brooklyn. Full dumpsters are emptied onto our open-air curing site on Governors Island, where piles of shells sit exposed to weather, sun, insects, and birds. In about a year, the tissue and pathogens are gone, and the shells are clean enough to be reused for oyster larvae to settle onto in our hatchery. Eventually, we bring them out to our restoration sites in fabricated reef structures to keep them out of the silty bottom of New York Harbor. Before COVID-19, we collected 7,000 to 10,000 pounds of oyster shells a week from the 75 restaurants in our program. Since 2015, we’ve collected 1.6 million pounds of oyster shells that would have otherwise ended up in the landfill.

Dunn: On Long Island, restaurants are more spread out, so we rely on volunteers to pick up 5-gallon buckets full of shells from 18 seafood restaurants. The Half Shells for Habitat project began in 2018 as a partnership between Seatuck, Adelphi University, and the towns of Brookhaven, Hempstead, and Islip. We’ve recovered over 70,000 pounds of shell so far.

Q: Do you have enough shells for your restoration projects?

Dunn: We could use more restaurants and collection volunteers on board, but it’s key to have all Long Island towns join in to recover instead of discarding shells. Ultimately, most of these shells support the shellfish sanctuaries around Long Island—that Governor Andrew Cuomo designated—and benefit towns through improved water quality, better wildlife habitat, and protection of shorelines from storms.

Wachtel: We know there are enough restaurants in New York City to increase our shell recycling, but with our current staffing and space capacity, we can’t add any more at the moment. To scale up, we’ll also need more funding. But, as Maureen said, there is much to gain, including habitat creation, protecting the shoreline from wave energy and erosion, and improving the harbor’s water quality.

Q: How can people support oyster restoration?

Dunn: Eating local oysters at restaurants creates demand for oysters grown in the clean Long Island waters. And oyster farmers and environmentalists working to restore wild reefs are not in competition; they benefit each other. Ask if your restaurant participates in shell recycling. They should be good neighbors and invested in their communities.

Wachtel: To help connect restaurants to recycling efforts, we recently launched the New York Alliance of Shell Collectors. We also think if New York joined other states, like Maryland, in providing incentives or reimbursements to restaurants—such as paying 10 cents per pound of shell recycled—more would participate. At an individual level, telling your local and state officials you support oyster restoration can help us get the permits we need for New York Harbor. And once we can gather safely again, we hope people will volunteer with Billion Oyster Project to help build our reef structures.

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