Oyster reefs were once a key feature of the New York / New Jersey Harbor Estuary's ecosystem. Oysters helped to feed New Amsterdam residents, particularly in winter when other foods were scarce. Oysters in fact remained the most common local street food through the 19th century. Yet as New York City grew, overfishing, pollution and siltation took their toll on the Harbor's oyster beds. By 1900, these were largely depleted or destroyed. Despite the fact that harvesting from any remaining beds was outlawed during the 1920s, the oysters never really returned.
Thanks to federal mandates and local investments, water quality in the Harbor has improved significantly in the last several decades. Oysters have begun to reappear, but only in some places, and in small numbers. In 1998, The River Project, an environmental organization based in Lower Manhattan, observed a significant "set" of wild oysters on the pilings beneath Pier 26 in Tribeca. The number of wild oysters on these pilings has increased since then, but not significantly.
A complete recovery of the oyster population in the Harbor appears to be hindered by a lack of oyster habitat - the reefs themselves, which chemically attract larval oysters and provide a surface to which they can attach.