Simone M. Scully

New York harbor was once the oyster capital of the world. In fact, what lobsters mean to Maine today, oysters meant to New York just a few centuries ago.

Archeologists have found middens — ancient piles of shells — dating back to 6950 B.C, suggesting that oysters thrived in the brackish waters around New York harbor for millennia, providing bountiful food to the Lenape people who lived in the region. Later, British explorer Henry Hudson found 350 square miles of oyster reefs when he sailed into the harbor in 1609 and as you would expect, it didn’t take long for European settlers to establish a booming oyster industry in the harbor shortly thereafter.

Before long, immigrants began calling Ellis and Liberty islands “Little Oyster Island” and “Great Oyster Island.” The Dutch paved Pearl Street in New York City with discarded oyster shells; while other shells were crushed into mortar paste for construction. Trinity Church is one example of a place built using this oyster shell-mortar paste. By the 19th century, New Yorkers ate about one million oysters every day, with higher-end restaurants, oyster cellars, cheap eateries and street vendors all serving oysters prepared or cooked in a variety of styles. All in all, 50 percent of all the world’s oysters were coming from New York harbor, providing food not only for the city’s residents, but also to much of the east coast and other regions further west.

Sadly, a combination of over-harvesting, raw sewage dumping, industrial pollution, and harbor dredging quickly brought an end to all of this.

By the early 20th century, the harbor was largely depleted of its oyster beds, and by 1927, the oysters that remained were no longer safe to eat. They remain that way today.

This dramatically altered the ecosystem of New York Harbor, says Katie Mosher, director of restoration for the Billion Oyster Project (BOP), a nonprofit that is working tirelessly to restore the New York Harbor’s oyster reefs.

Oysters, even though they may be small mollusks, play a vital role in their habitat. They are natural purifiers, which means that clean and filter water as they eat, removing dangerous pollutants, such as nitrogen which, can trigger algal blooms when levels get too high, depleting water oxygen and killing off living organisms in that zone. One single adult oyster can clean about 50 gallons of water every day.

Oysters also build three-dimensional reef structures that, like coral reefs, provide a habitat for a number of other species, from tiny microorganisms that live in the nooks and crannies created by their shells to larger species such as seahorses, whales and seals that feed on the critters living on the reef. Oyster toadfish, for example, like to hide and lay their eggs in the crevices of oyster reefs, while blue crabs use the reefs as hunting grounds.

The reefs also provide natural breakwaters, or underwater barriers, that soften the blow of large waves, helping prevent storm surge and the erosion of shorelines.

So when these natural oyster reefs around New York Harbor were destroyed, explains Mosher, “a really important and vital landscape disappeared.”

“Just imagine a forest disappearing from a landscape and all the animals that go with it being wiped out as well,” she continues. “That’s why restoration is so important. We’re trying to restore that critical lost landscape.”

To accomplish this, they want to restore one billion oysters to the region by 2035.

Of course, this is not a quick or easy task. In many places in the harbor, the rocky hard bottom that oysters use to latch on to and form reefs has been destroyed or disappeared. Without that hard surface, oyster larvae have nothing to grow on, causing them to sink into the soft, muddy floor and die.

So, to restore the reefs, Mosher says, “one of our major [restoration] initiatives is to build a structure called a gabion, which is an 8 by 2 by 2 foot welded steel cage.” This cage, she explains, can then be filled with recycled oyster shells collected from more than 70 restaurant that BOP partners with across New York City. So far, they’ve collected a million pounds of oyster shells from these restaurants, diverting them from landfills in order to recycle them for oyster reef restoration.

These shells are then cured, which means that they are left outside for the elements to naturally cleanse them of any organic matter or pathogens that could cause harm to baby oysters, or oyster larvae.

Once cured, these recycled shells offer the perfect structures for oyster larvae to latch onto in the water. Just one reclaimed shell can house 10 to 20 new live oysters. So, when these shells are placed in the water in areas, such as in the upper Hudson River, where there are some wild oyster populations remaining, they can help recruit and jumpstart the creation of new, artificial reefs.

In places where there are few or no wild oyster populations left, BOP takes an extra step. Instead of just placing the cured shells in the water as is, they work with their partner, the hatchery at the New York Harbor School on Governors Island, to grow and hatch baby oysters that are attached to the cleaned shells prior to being placed in gabions. They are then strategically placed off New York’s coastline in the hopes that they’ll create brand new reefs.

So far, BOP has started 12 artificial reefs — containing 28 million oysters — across the harbor, some close to shore, others further out in deeper water. Of those 12, four are “community reefs” where local New Yorkers can volunteer to help monitor oyster reef health and growth. They also have three floating oyster hubs active off piers, marinas, and basins to grow new oysters. BOP also teams with more than 70 public schools across the city, allowing students to help monitor water quality and oyster survival, while also learning about the importance of oyster restoration in the process.

In total, those twelve artificial reefs amount to 7 acres, a far cry from the historical numbers New York once knew, but they still represent a very important step forward in BOP’s ongoing work because these reefs are already yielding promising results.

“This past summer in 2018, we had a really abundant wild oyster set in the upper Hudson, as well as further down the Hudson river near Manhattan. We even saw some as far down as Coney Island creek,” says Mosher. “We saw wonderful settlement of baby oysters onto a lot of the structures we put in the water and even some natural habitat in a few rocky places.” Hopefully with more progress like this, the help of BOP and the dedication of local volunteers and students, the reefs in New York harbor will one day again be as thriving and diverse as they once were.