Billion Oyster Project — Restoring Native Oyster Reefs in New York Harbor

Billion Oyster Project was founded in 2008 by the New York Harbor School, a New York City public high school, with the goal of restoring one billion native oysters to New York Harbor by 2035 while engaging one million people in the effort. Oysters were functionally extinct in the harbor after over a century of dredging, pollution and overharvesting, despite once forming reefs covering an estimated 220,000 acres.
The project's mechanism combines shell recycling and reef engineering with education: used oyster shells are collected from more than 75 partner NYC restaurants, cured, and used as cultch (settlement substrate) for hatchery-raised oyster larvae, then deployed as reef structures — including bay balls, shell mounds, gabions and supertrays — at 8-plus monitored sites across the harbor, including Jamaica Bay, the Hudson River, the Upper Harbor and Western Long Island Sound. More than 11,000 public school students and over 16,000 volunteers have taken part in restoration and monitoring work.
Reported totals vary by publication date: the organisation's own site cites over 150-200 million oysters restored across roughly 17-19 acres of reef and around 2-3 million pounds of shell recycled (as of late 2025), while New York State announced a 2024 milestone tied to the Jamaica Bay reefs. A 2015 National Science Foundation grant of $5 million funded expansion of the schools programme, and the project is a named partner in New York State's $107 million Living Breakwaters coastal-resilience project in Staten Island (part-funded by a $60 million HUD disaster-recovery grant after Hurricane Sandy). Long-term monitoring has confirmed oysters can survive and reproduce in the harbor.
Caution: the specific oyster-count and acreage figures come from the organisation's own reporting (corroborated in totals, though not in exact numbers, by Wikipedia and New York State's announcement); no independently published, peer-reviewed population survey or water-quality-improvement measurement at these reef sites was found in this research, so ecosystem-service claims like filtration should be read as biologically plausible rather than locally measured.

Read the full analysis: https://www.billionoysterproject.org/restoration