Jules Stewart reports on the ambitious plan to bring oysters back to New York Harbor, which once had the world’s richest beds of the molluscs
Before hot dogs and pretzels, there were oysters. As early as the 18th century, pushcarts hawking oysters harvested from New York Harbor were a common sight in the streets of what is today Lower Manhattan.
The abundance of these molluscs in the city’s waterways was such that Pearl Street, which traverses the Wall Street Financial District, was paved with oyster shells.
In 1609, the English navigator Henry Hudson, on his voyage to find a western sea lane to China, was the first European to explore New York Harbor and its scattering of 42 islands and almost 850 kilometres of waterfront.
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He gazed upon Manahactanienk, a Munsee Indian name signifying ‘the place of general inebriation’. This was Manhattan, a 58-square-kilometre island inhabited by several native tribes at the time of Dutch colonisation 18 years after Hudson’s first sighting.
‘Hudson found a local population feasting on excellent New York Harbor oysters,’ says historian Mark Kurlansky. ‘We know that the Lenape [tribe] ate copious quantities of oysters because oyster shells last a very long time and they left behind tremendous piles of them.’
Accumulations of thousands of shells have since been unearthed across the city’s five boroughs. It’s believed that the harbour once held half the world’s oyster population, a phenomenon reflected in the Dutch names for Ellis and Liberty islands: Little Oyster and Great Oyster. Most estimates put the city’s oyster population in Dutch colonial times in the billions, with more than 89,000 hectares of reefs covering 900 square kilometres of waterway that served as the habitat for a great variety of marine species.
As late as the 1800s, oysters proliferated in New York Harbor. ‘By 1970, all that had changed,’ says Giovanna Kupiec, a crew member of the Billion Oyster Project (BOP). The organisation was founded in 2014 with the goal of restoring one billion oysters and 40 hectares of habitat to New York Harbor by 2035.
‘The harbour had effectively died as a result of overfishing, decades of industrial pollution and the dumping of untreated sewage.’ What was once New York’s favourite culinary delicacy had become virtually extinct.
Due to fears of food-borne illness, including typhoid, in 1921, the New York City Health Department shut the Jamaica Bay oyster beds, which had provided some 80 million oysters a year. Six years later, the last New York City oyster bed was closed in Raritan Bay.
‘New Yorkers live in what was once one of the world’s richest and most productive ecosystems, and the engineer of that ecosystem was the oyster,’ says Kupiec. ‘They acted as the lungs of the harbour, filtering its water and ensuring its health.’
Oysters play a crucial role in maintaining water quality through their natural filtering abilities. As filter feeders, they consume a wide range of particles suspended in the water, including algae and phytoplankton, as well as excess nutrients. BOP’s director of programmes, Katie Mosher, says, ‘We are looking to create multi-acre restoration projects and reinstall hard harbour floors to ensure that the oyster population can carry on reproducing year after year.’
To do this, BOP collects oyster shells from restaurants around New York City, such as Grand Central Oyster Bar and Gramercy Tavern, to help seed the new oyster beds. Oyster spats (juvenile oysters), float around oyster beds until they find a good surface to call home, and an old oyster shell from a New York restaurant works well.
Oysters draw in water through their gills using tiny hair-like structures called cilia. These cilia create a current that pulls water into the oyster’s body. As water passes over the gills, solid particles become trapped in mucus secreted by these gills. This serves as a sticky trap for food and other particulates, which are then transported to the oyster’s mouth for consumption.
An adult oyster can filter a substantial amount of water, up to 190 litres per day under optimal conditions. This filtering process helps remove pollutants and excess nutrients from the water column.
The good news is that New York Harbor is starting to make a comeback, thanks to the efforts of BOP and its partner Hudson River Park Trust (HRPT), which hosts 15 BOP oyster research stations at various sanctuary locations.
The organisation was established in 1998 by New York State to design, build, operate and maintain a new public park and estuarine sanctuary in and along several miles of the Manhattan shoreline. HRPT’s 6.5 kilometres of waterfront esplanade and piers afford space to collect data on oyster growth, biodiversity and water quality. ‘What we are seeing today is an opportunity to improve the health of our nearshore areas, including the oyster habitat,’ says HRPT’s vice- president of estuary and education, Carrie Roble.
‘Their wild population is dynamic and it’s expected that not all the reintroduced oysters are going to survive. Natural attrition will bring an estimated 40 per cent reduction in numbers in the first few years. This is one reason why the restoration projects are being phased.’
The benefits of breeding oysters and better sewage- disposal practices have already changed the course of New York Harbor life. Compared with 50 years ago, today there’s a lot of life in the harbour, along with more biodiversity and bio-productivity. This has been achieved largely thanks to putting an end to the practice of dumping millions of gallons of raw sewage into the harbour every day.
In 2024, the Lower Hudson River Estuary and Harbour experienced the biggest recruitment of spats that the region has seen since surveys commenced in 2018. The Hare Lab at Cornell University, along with HRPT and BOS, deployed shell bag ‘collectors’ throughout the lower estuary to understand the dispersal and settlement behaviour of spats. This unprecedented recruitment is expected to mark the successful start of a restored oyster population.
BOP’s Katie Mosher says she’s encouraged by the preliminary data for 2024. ‘This was the biggest year ever for oyster replenishment. If we are successful here, it means our work can be reproduced in other parts of the world.’
Apart from ensuring an unpolluted water habitat, oysters can play a strategic role as protection against future storm surges. A series of oyster walls reinforced with concrete are being introduced in Staten Island, whose south shore neighbourhood of Tottenville was severely damaged by Hurricane Sandy, the destructive tropical cyclone that hit New York in October 2012.
This four-kilometre reef, whose construction began in 2021, has already started to attract marine life. It also serves to clean the surrounding water and, most importantly, protect against future storm surges.
The oyster walls serve to reduce water velocity, erosion of the shoreline and the height and intensity of waves. Residents of Tottenville, once known to Staten Islanders as ‘the town that oysters built’, are now betting on these molluscs as their best shot at survival in future tropical storms.
This threat is genuine, as reflected in a US Army Corps of Engineers proposal for a US$52 billion plan, developed in the aftermath of Hurricane Sandy, to protect the New York City metropolitan area from storm surges and coastal flooding. The scheme that was tentatively selected would see the construction of 12 storm surge gates across some of the largest waterways around the New York City region.
It would also erect coastal barriers across more than 66 kilometres of shoreline, including an extensive system of seawalls and floodwalls that would make this one of the largest infrastructure projects in the city’s history.
‘We are looking for ideas to help soften storm energy as it reaches the shoreline, including an oyster reef to lessen the impact of storm water,’ says BOP’s Katie Mosher. ‘This will be part of the Living Breakwaters project, enhanced by oysters, that is scheduled to start in 2025.’
The Living Breakwaters project consists primarily of 730 metres of near-shore breakwaters. These are partially submerged structures built of stone and ecologically enhanced concrete units that break waves, reduce erosion of the beach and provide a range of habitat spaces for oysters, fin fish and other marine species. The Living Breakwaters concept was developed by a multi-disciplinary team that won a US Department of Housing and Urban Development competition after Hurricane Sandy.
There’s no doubt that the humble oyster is destined to play a leading role in the battle against water pollution and the storm surge threat that New York City faces. ‘Restoring the oyster population will filter our harbour, cleaning it for us and our aquatic neighbours,’ says BOP’s Giovanna Kupiec. ‘Restored reefs will provide living space for an abundance of species and rebuild an ecosystem as diverse as the city above. We New Yorkers need to bear in mind that we are islanders who live together along the shore.’
