The Billion Oyster Project reefs in New York Harbour now cover 19 acres and have filtered tens of trillions of gallons of water, the result of turning oyster shells scraped from restaurant plates into living reef infrastructure on the floor of one of the world’s busiest urban waterways.
The numbers behind the effort are hard to dismiss. Staff estimate that 200 million live oysters, raised on 3.2 million pounds of discarded shells collected from around 75 partner restaurants, have done that filtering work across nearly two decades of operation. According to Space Daily, by the end of 2025 the project had collected 3.2 million pounds of shell and restored more than 180 million oysters to the harbour. The project was launched in 2008, with its headline goal of one billion live oysters set for completion by 2035. At roughly 20% of that target, there is still a long way to go.
How the Billion Oyster Project Reefs Are Built
The operation runs from a hatchery on the southern part of Governor’s Island. Restaurants divert spent oyster shells away from municipal landfill and deliver them to a curing pile on the island, where they sit until they are clean. ‘We take the oyster shells from restaurants and bring them to our shell pile,’ Agata Poniatowski, education outreach coordinator for the project, told ABC News. ‘Once there’s no bacteria and no invasive species, no disease, we bring them to our hatchery.’
At the hatchery, oyster larvae are released onto the cured shells, where they settle, acclimatise to New York water, and begin to grow. Up to 10 million baby oysters can be raised at once, before being bagged and trucked out to reef sites across the harbour. Once deposited, they get on with the work the project was designed around: filtering water, hosting marine life, and absorbing the energy of incoming waves.
‘Oysters are what we call a keystone species, meaning if the oysters are thriving in an environment all other biodiversity is thriving in that environment,’ Bela Altman, Volunteer Coordinator for the Billion Oyster Project, told Reuters. That framing shapes how the project positions its ambition. Restored oyster reefs do not just clean the water; they function as habitat infrastructure for everything living alongside them.
What One Billion Oysters Would Mean for the Harbour
The project’s stated goal is to restore 100 acres of historic oyster reef, much of it lost over centuries of dredging and pollution. At full scale, 100 such reefs could refresh the entire water volume of New York Harbour every three days. That is not a trivial claim in a harbour that receives runoff from one of the densest urban environments on the planet.
There is also a climate dimension to the work. Oyster reefs disperse the energy of incoming waves, which matters in a coastal city where storm intensity could increase over time. The reefs would reduce the risk of severe flooding in ways that engineered sea walls cannot easily replicate, because the biological structure absorbs and diffuses rather than deflects.
Getting to the current scale of efficiency was not straightforward. The curing process alone, in which shells must be left outdoors until they are entirely free of bacteria, invasive species and disease, takes time and space. Coordinating shell collection from dozens of restaurants across a city the size of New York, while maintaining the biological integrity of the hatchery, required years of logistical refinement.
The project’s next milestone is bringing the Billion Oyster Project reefs to the full 100 acres by its 2035 target date, adding roughly four times more restored reef area than currently exists. With 75 restaurant partners already contributing shells and 10 million juvenile oysters capable of being raised in a single hatchery cycle, the pipeline exists. Whether the pace accelerates enough to close that gap in the time remaining is the question the project’s next decade will answer.
