Oysters and Students May Revive New York's Famed Harbor
With the help of city school kids, an organization is restoring long-depleted oyster beds that once flourished in the waters that surround New York City. The bivalves are cleaning the water and protecting shorelines.
Along the way, the compact boat cuts a curving path between the numerous ferries, pleasure craft, barges and tugboats that ply the river. Since larger boats always have the right of way, Captain Weston steers clear of almost everything in his path. Early in the trip, there is an incessant buzz of helicopters overhead, on their way to and from a helipad at the base of Wall Street. Upriver, the sky belongs to commercial jets. In between, the vessel and its cargo pass beneath a series of iconic bridges and around several city islands. As the hour passes, so do the clouds.
The young oysters will be piled atop Soundview Reef, an existing five-acre reef made from shells dropped into the water on previous trips to the site. This is just one of several locations around the city where new oyster reefs are being established by the Billion Oyster project with the help of an army of volunteers and area students. The renewed population of oysters will not be suitable as food. But they are expected to serve a more important purpose: naturally filtering the water, attracting other underwater life and protecting shorelines from future storms.
As its name implies, the Billion Oyster Project aims to replenish the once-plentiful bivalve in and around New York Harbor. But the lofty goal represents only a fraction of what once was.
A Legacy of Pollution
When English explorer Henry Hudson arrived more than 400 years ago, there were 220,000 acres of oyster beds in the harbor, constituting nearly half of all the oysters in the world. As the city’s population grew, so too did its appetite for oysters, a favorite of the well-to-do, the down-and-out and everyone in between.
By 1820, the oyster beds around Staten Island had been depleted. Even so, harvesting continued until the turn of the last century when over a billion oysters a year were taken from the water, something that proved to be unsustainable. The last New York oyster bed was closed by the city in 1927. But over-harvesting was not the only cause of the oyster’s demise.
The Manhattan shoreline was once naturally hospitable to oyster beds. But now nearly all of it has been altered by landfill and innumerable piers and pylons. Until the 1970s, the city was dumping millions of gallons of untreated sewage into its waterways every day. Because of an aging combined sewer system, raw sewage is still discharged into the water during heavy storm events. But the harbor is cleaner today than it’s been in over 100 years.
An adult oyster can filter 50 gallons of water a day, cleaning the harbor of pollutants, including nitrogen, which causes oxygen-depleting algae blooms. As they grow, oyster reefs provide habitat for fish, crabs and other marine wildlife, re-establishing the harbor’s underwater ecosystem. By dissipating wave energy, established reefs can benefit the land as well, acting as a defense against storm surges, flooding and shoreline erosion.
Students on the Front Lines
The Billion Oyster Project began in 2014 with the goal of restoring one billion oysters to New York Harbor by 2035. “That’s our best guess as to when the harbor could begin to rejuvenate itself, without human intervention,” says the project’s communications director Helene Hetrick. “It’s not to say that our work will be completely done by then, but we think we will have reached a turning point for the harbor.”
But student outreach is not limited to the Harbor School. Since it began eight years ago, the Billion Oyster Project has worked with more than 100 schools in New York City, “The dual mandate of restoration and education gives us the best chance at long-term sustainable change,” Hetrick says. “Bringing in the next generation of stewards is what makes the project even more challenging, but also more exciting.”
Much, if not most of the reef construction and monitoring, as well as water quality monitoring, is done by students from all parts of the city.
Where Oysters Come From
In nature, young oysters, known as spat, need a hard surface to settle on and grow their own shell. In order to speed up the process, the Billion Oyster Project matches oyster larvae with shells donated from 55 area restaurants, down slightly from pre-pandemic numbers. To date, 2 million pounds of oyster, clam and scallop shells have been collected for reuse and diverted from landfill. Before they can be used, the shells spend up to a year curing outside in piles on Governors Island. They must be free of any pathogens or bacteria before re-entering the harbor.
After they have cured, the shells are cleaned and placed inside a “gabion,” a container of metal bar and mesh welded and assembled by Harbor School students and staff. The gabion full of shells is then lowered into a tank of water. Free swimming oyster larvae are released into the tank and attach themselves to the shells. Not much larger than a grain of sand, as many as 20-30 spat can find a spot on one shell. Once they are set on their new home, the entire structure is lowered into New York’s waterways. But not all of them will make it. “Twenty oysters can’t grow on one shell,” says Hetrick. “They’ll compete for space. We hope at least half of them will survive.”
The fledgling oysters dumped overboard today off the Bronx will drift down and settle upon 200 gabions waiting at the bottom. After the crews have stacked the empty crates, the two buoy tenders untie themselves, lift anchor and turn toward home. Some of those on board are graduates of the Harbor School. Others will be starting classes in a few weeks. All will continue working toward their common purpose: restoring New York Harbor, one batch of oysters at a time.