Northeast Coastal Areas Study
Significant Coastal Habitats
Site 15 (NY)
I. SITE NAME: Moriches Bay
II. LOCATION: An area of open water located between the barrier island chain of portions of Fire Island and Westhampton Beach and the south shore of Long Island from Smith Point to Moneybogue Bay and Westhampton Beach.
TOWNS: Brookhaven, Southampton
COUNTY: Suffolk
STATE: New York
USGS 7.5 MIN QUADS: Pattersquash Island, NY
40072-67; Eastport, NY 40072-76; Moriches, NY 40072-77
USGS 30x60 MIN QUAD: Long Island, East 40073-E1
III. GENERAL BOUNDARY: The entire 8,900 acre (3,605 ha) aquatic environment of Moriches Bay and adjacent marshes along the south shore of Long Island constitute the overall boundary of this complex, and is delineated on the accompanying map. The western boundary of this complex is the Smith Point Bridge; the eastern boundary is Moneybogue Bay. Included within the bay ecosystem are: 1) the barrier beach island, tidal saltmarshes, dredge spoil islands and intertidal flats from Smith Point Bridge to and including Cupsoque County Park, 2) the William Floyd Estate, and 3) Moriches Inlet.
IV. OWNERSHIP/PROTECTED STATUS: The barrier island portion includes Federal and County parks, although the Town of Brookhaven retains ownership to offshore islands including East and West Inlet, Carters Island and New Made Island. The 613 acre (248 ha) William Floyd Estate is located on the south shore of the mainland, and is owned and managed as a historic site by the National Park Service. Moriches Inlet is within the Town of Brookhaven, bounded on the east by Cupsoque County Park and on the west by Smith Point County Park. The north side of the bay is primarily in private ownerships.
V. GENERAL HABITAT DESCRIPTION: Moriches Bay is part of a succession of shallow, protected saltwater embayments separated from the Atlantic Ocean by a series of low-lying barrier islands. The bay is fed by numerous small freshwater coastal streams that originate from groundwater on the mainland, the Forge and Terrell's Rivers, and ocean water transported through Moriches Inlet. The barrier island is characterized by sandy beaches and dunes on the ocean side and salt marshes and tidal flats bordering the bay. About 50% of the bay area constitutes marshes and shoals.
Near the inlet, and offshore of tidal marshes and spoil islands, extensive mud and sand flats are exposed at low tide. Vegetation on the barrier island is typical of coastal plant communities - tidal areas are dominated by cordgrasses (Spartina alterniflora and S. patens) while dense shrub thickets comprised primarily of beach plum (Prunus maritima), bayberry (Myrica pensylvanica) and poison ivy (Toxicodendron radicans) have developed in backdune sand swales and other areas above tidal influence. Beachgrass (Ammophila breviligulata) occurs on primary dunes.
Habitat in the William Floyd Estate is diverse, ranging from tidal saltmarsh through brackish and freshwater systems, with a gradual transition to upland deciduous forest. Several large, open fields occur at the site and are managed for grasses and forbs.
VI. SIGNIFICANCE/UNIQUENESS OF AREA: Moriches Bay is of regional importance for marine finfish, shellfish, waterfowl, shorebirds and many other species of breeding, wintering and migratory wildlife. This abundance of species is a result of the rich estuarine habitats around rivers and streams on the mainland, the high primary productivity of saltmarshes that fringe the inner, bayside shore of the barrier island, and Moriches Inlet, which exchanges and circulates bay waters. Moriches Inlet provides a corridor for fish migration into the bay and is a prime feeding area for adult striped bass (Morone saxatilis), bluefish (Pomatomus saltatrix), American lobster (Homarus americanus) and other wildlife including common terns (Sterna hirundo) and U.S. Endangered roseate terns (Sterna dougallii).
The bay supports a regionally outstanding winter flounder (Pseudopleuronectes americanus) fishery and serves as both nursery and foraging ground for yearling striped bass and bluefish, American shad (Alosa sapidissima) and summer flounder (Paralichthys dentatus). Species which spawn in the bay include winter flounder, weakfish (Cynoscion regalis), Atlantic silverside (Menidia menidia), killifish (Fundulus spp.) and American sandlance (Ammodytes americanus), as well as the commercially valuable blue crab (Callinectes sapidus) and hard-shell clam (Mercenaria mercenaria). The Forge River is reportedly a locally important spawning ground for striped bass. In addition, many species of migratory birds use the bay's saltmarsh and dredge spoil islands during the breeding season. The waters of Moriches Bay support significant concentrations of wintering waterfowl, especially American black duck (Anas rubripes) and scaup (Aythya affinis, and A. marila). Harbor seals (Phoca vitulina) also make use of the bay in winter.
Roseate and common terns nest in large numbers on a dredge spoil island just east of the Moriches Inlet (East Inlet Island), using both the bay and the inlet as foraging habitat. A second spoil island west of the inlet supports a rookery of great and snowy egrets (Casmerodius albus and Egretta thula, respectively). Seaside and sharptail sparrows (Ammodramus maritimus and A. caudacutus, respectively), clapper rail (Rallus longirostris) and green-backed heron (Butorides striatus) nest in adjacent saltmarshes. The extensive tidal mudflats are a rich feeding ground for thousands of migratory shorebirds which include whimbrel (Numenius phaeopus), sanderling (Calidris alba), dowitcher (Limnodromus spp.), and several species sandpipers and plovers, including the U.S. Threatened piping plover (Charadrius melodus). Piping plover and least tern (Sterna antillarum) nest on the sandy beaches of the barrier beach complex from Watch Hill on Fire Island to Cupsoque County Park. The flats also provide habitat for wintering sanderlings.
Northern diamondback terrapins (Malaclemys t. terrapin) inhabit the marshes and waters of the bay, going ashore to breed in the dunes and sandy swales of the barrier beach. The entire barrier island is important as a hunting ground for migrating and wintering hawks and owls including peregrine falcon (Falco peregrinus), a U.S. Threatened species, northern harrier (Circus cyaneus), short-eared owl (Asio flammeus) and snowy owl (Nyctea scandiaca).
The upland community of the William Floyd Estate provides habitat for breeding American woodcock (Scolopax minor) and a variety of migrating and nesting songbirds, while adjacent tidal areas afford habitat for nesting American bittern (Botaurus lentiginosus), seaside sparrow (Ammodramus maritimus) and osprey (Pandion haliaetus). This area is one of the few remaining on the south shore of Long Island where tidal wetlands are contiguous with an undeveloped upland buffer.
VII. THREATS: Intense recreational pressure on Fire Island National Seashore and in the County parks, including the use of off-road recreational vehicles, has disturbed or destroyed least tern and piping plover nesting areas and has contributed to destruction of dune and marsh habitats. There is an absence of active management of breeding bird colonies by either Federal, Town or County agencies to control human disturbance, vegetation and/or predators. As a result, at least one of the breeding islands formerly used by roseate and common terns has been co-opted by gulls and a major least tern nesting colony was destroyed by recreational vehicles at Cupsoque County Park in 1989.
Increasing development of the mainland shoreline to private residences, including high density condominiums and townhouses, is altering and eliminating tidal and freshwater wetlands, thereby posing a threat to wildlife species dependent on these habitats. The expansion of marina facilities, increased recreational fishing pressure and water quality degradation from road runoff, septic systems and duck farm wastes is negatively impacting the Moriches Bay ecosystem.
VIII. CONSERVATION CONSIDERATIONS: The limited nesting and feeding areas for threatened, endangered and special concern species needs to be safeguarded and more effectively managed using a variety of mechanisms including beach closures, cooperative agreements, beach warden patrols, public education and predator removal. Efforts should be made to identify and implement pertinent tasks and objectives of the piping plover and roseate tern recovery plans that may be applicable to this area. Designation of the bay and its special habitats as part of a National Estuarine Research Reserve or as Wetlands of International Importance under the Ramsar Convention would provide much-needed habitat enhancement, protection and management oversight of these regionally significant waters and wetlands as well as national and international recognition. Such designation may help to curtail the development of the remaining shoreline and wetland habitats. Consideration should be given to the elimination of duck farm wastes entering the estuary and to controlling non-point sources of pollution, especially from road runoff, as a means of protecting the bay fishery and maintaining habitat quality. Active management of colonial waterbird nesting habitat may increase the potential for recolonization of suitable nesting areas.
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