New York Harbor was once home to half the world's oyster population, according to biologists' estimates, but overconsumption and pollution devastated the population. In the mid-19th century, after eating oysters was linked to typhoid, the Health Department closed all of the city's oyster beds, with the last one shut down in 1927. Over the past decade, however, one of the city's "most ambitious rewilding initiatives" has planted 150 million larvae, aiming at seeding a billion oysters in the city's waterways by 2035.
For at least 6,000 years, oysters thrived in the Hudson River estuary, becoming "deeply woven into the life of East Coast cities," said BBC Future. Now, the goal of the Billion Oyster Project is "restoring the city's coastal habitat, improving water quality and educating the public." Oysters absorb pollutants when they filter the water, and one adult oyster can filter 50 gallons a day, said The New York Times.
Oysters also "enhance biodiversity." Animals like shrimp and snails grow on their shells, providing food for fish. They offer a natural defense against coastal erosion and are the "key in the fight against rising seas and flooding."
Restoring the reefs could help to protect the city from extreme storms, according to a recent study in Nature. Wave energy accelerates over the bottom of a river, but reefs absorb much of the momentum. The Solent Seascape Project, one of the biggest restoration projects in Europe, recently used $5 million of funding to introduce more than 14,000 oysters into the River Hamble, said South West Londoner. Other oyster restoration projects are under way in Australia, Bangladesh and Hong Kong. | 
