In 1998, the New York State Hudson River Park Act created a major new park on the west side of Manhattan. As part of the enacting legislation, the park’s water area (a total of about 400 acres) was designated as the Hudson River Park Estuarine Sanctuary. This designation acknowledges the importance of the sanctuary as an official New York State Significant Coastal Fish and Wildlife Habitat, and highlights the need to provide public access to the river in a manner that promotes and preserves the sanctuary’s marine resources.

The Act required the preparation of a sanctuary management plan in consultation with the public, government agencies, and other cooperating organizations. Under the direction of the Hudson River Park Trust, the Estuarine Sanctuary Management Plan was prepared to identify management policies for the sanctuary in the areas of resource protection, public access and recreation, education, and research. It also provides guidance on balancing the needs of various park uses, and identifies procedures for monitoring and enforcing park policies, laws, and regulations.

The sanctuary’s habitat is a main channel shoreline within the Hudson River Estuary.
Phytoplankton, zooplankton, and benthic macroalgae and invertebrates form the base of the sanctuary food chain. More than 70 fish species have been reported locally, with the most frequently observed species being the winter flounder, weakfish, cunner, Atlantic silverside, Atlantic menhaden, spotted hake, white perch, hogchoker, seaboard goby, bay anchovy, and larval American sand lance. Anadromous species (fish that move from the ocean to the river for breeding) are typically found in the estuary during spring and fall and include Atlantic tomcod, alewife, and American shad. Striped bass use the river for migration but also use the interpier areas as overwintering habitats. The only catadromous species (fish that move from river to ocean for breeding) found in the sanctuary is the American eel. Eels spawn at sea and their young move into the estuary in the spring.

Birds also use various habitats along the river’s estuarine shoreline for nesting, feeding, overwintering, and during fall migration. Several species of waterfowl - primarily mallards, black duck, Canada goose and gadwall - breed in and around the harbor. The Atlantic Brant, Greater Scaup, American black and canvasback ducks, and more than 30 species of shorebirds regularly migrate through the park for feeding. Breeding raptors include the northern harrier, osprey, peregrine falcon, and common barn owl. Raptors known to overwinter include the rough-legged hawk, American kestrel, short-eared owl, and long-eared owl. Both short- and long-distance migratory songbirds occur, as well as resident and overwintering songbirds. Breeding songbirds include the song sparrow, American robin, gray catbird, yellow warbler, and red-winged blackbird.