A full-grown oyster, it is frequently reported, can filter 50 gallons of water in a day. The mollusk will ingest bacteria that can cause disease, nitrogen that can accumulate to create dead zones, and other suspended solids that can include contaminants. It will then fix these particles to its shell, absorb them into its tissues, or bind them together and excrete them as “pseudofeces” that will sink to the bottom of its aquatic habitat. The same, seemingly magical processes that help clear the water can make oysters dangerous to eat, and so the New York State Department of Environmental Conservation (DEC) prohibits their cultivation in the waters surrounding the five boroughs of New York City.
Coney Island Creek, a tidal inlet that separates the western end of the Coney Island peninsula from the Brooklyn mainland, harbors heavy metals and toxic compounds derived from coal and oil processing: residues of historical industrial activity in the area. Stormwater and sewage outflows bring high levels of coliform bacteria after heavy rainfalls. This particularly polluted waterway is being evaluated for addition to the federal Superfund program to compel cleanup on a large scale. When the Billion Oyster Project (BOP, named after their goal of restoring one billion oysters to New York harbor by 2035) sought to install a small man-made reef there, DEC resisted providing permits, lest the “attractive nuisance” poison locals who commonly walk, fish, and conduct baptisms and other rituals along the creek.
BOP persisted and, in 2018, installed a “community reef” at the edge of Kaiser Park, near a popular fishing pier that already supported its own wild oyster population. Today, thousands of new oysters grow in an “oyster filing cabinet” made of two steel rebar racks. When they reach one year of age or three inches in size, the oysters are transferred to a less accessible reef, as per DEC requirements, and the cabinet is restocked. Despite adverse conditions, the oysters have thrived and attracted other species to the site: mudsnails, hermit crabs, cone jellies, shrimp, Atlantic silversides, and groups of students from local schools. Between May and October, BOP monitors the site monthly, and hosts programs for youth and volunteers to study the reef. After being briefed on safety, wrapping up any exposed cuts, and donning boots or waders and gloves, participants pull out the files, measure and weigh the oysters, examine water quality, and learn about the history and ecology of New York harbor.
The Coney Island Creek reef is one of twelve field stations BOP currently operates across the city, alongside dozens of smaller oyster research stations operated in partnership with local schools. Other environmental groups also maintain large reefs in the harbor. Before pollution and overharvesting effectively annihilated the population in the early 1900s, oysters had been central to New York City’s food supply, and, some argue, its very identity. In ecological terms, the oyster is a keystone species whose complex reef architecture creates habitat for other species, as well as providing “ecosystem services” for human populations. Efforts to restore oysters to the harbor, which began in the 1990s, have picked up steam over the last decade, driven in part by the bivalve’s cultural cachet. Visions of an “oystertecture” to remediate the Gowanus Canal played a starring role in a 2010 exhibit at the Museum of Modern Art. City restaurants tout their programs to send spent shells from plateaux de fruits de mer to BOP’s hatchery where oyster larvae bred mostly from healthier sources in Maine waters can attach themselves and grow before being redeployed to a reef or research station.
News headlines and even national morning TV segments regularly ask: “Can oysters clean up New York’s harbor?” To which BOP’s answer is: “Not really.” There are steep barriers to rebuilding reefs on a large scale, and little scientific evidence of their decontamination of waters. For now, studies focus more on how water quality impacts oysters’ performance than the other way around (scientists are also looking to the hardy ribbed mussel to improve urban water quality). Oyster restorers emphasize habitat creation, and maybe wave attenuation: not cleanliness but climate resilience. In a recent survey, New York City-area oyster restorers reported their greatest success in cultivating public attention and engagement. Oysters introduce people to the harbor, its social and ecological value, and the work that remains to be done to improve its health. In many environmentalists’ theory of change, the hands-on experience with oysters seeds new stewards of the harbor and advocates for new environmental policies and a robust marine economy. Since 2021, BOP has rearticulated its mission as restoring one billion oysters and engaging one million people. We take care of oysters, and the oysters take care of us. It is a vision of a future more aligned with and attuned to the water’s health, with, naturally, benefits for humans, too.