Northeast Coastal Areas Study
Significant Coastal Habitats
Site 16 (NY)
I. SITE NAME: Great South Bay
II. LOCATION: An area of open water, shoreline and tidal saltmarsh located between the barrier island chain from Gilgo Beach east to Smith Point Bridge on Fire Island and the south shore of Long Island from Nassau Shores to Smith Point.
TOWNS: Babylon, Brookhaven, Islip
STATE: New York
USGS 7.5 MIN QUADS: Pattersquash Island, NY 40072-67; Howells Point, NY 40072-68; Bellport, NY 40072-78; West Gilgo Beach, NY 40073-54; Sayville, NY 40073-61; Bay Shore East, NY 40073-62; Bay Shore West, NY 40073-63; Amityville, NY 40073-64; Central Islip, NY 40073-72
USGS 30x60 MIN QUADS: Long Island, East 40072-E1; Long Island, West 40073-E1
III. GENERAL BOUNDARY: The entire 64,000 acre (25,920 ha) aquatic environment of Great South Bay and adjacent marshes along the south shore of Long Island constitute the boundary of this complex. The western boundary is the Gilgo Cut boat channel (Town of Babylon) and the eastern boundary is the Smith Point Bridge in Brookhaven Town (see accompanying maps). Areas of fish and wildlife significance, in addition to the waters of Great South Bay, include the Captree to West Gilgo barrier beach, tidal saltmarshes and islands; the Connetquot River estuary; Champlin Creek estuary and tidal wetlands; Orowoc Creek wetlands and uplands; Fire Island Inlet; Carmans River estuary; Yaphank Creek; the Southaven Properties; the former Robinson Duck Farm and the Fire Island National Seashore Wilderness Area.
IV. OWNERSHIP/PROTECTED STATUS: The Great South Bay land ownerships include Federal, State, County, Town (Babylon, Islip, and Brookhaven Town), and private holdings. Connetquot River and Heckshire State Parks (on the Long Island mainland) and Gilgo, Captree, and Robert Moses State Parks (on the barrier island) comprise the State holdings. On the western barrier island, Islip and Babylon Town lands are interspersed with State-owned parklands. On the mainland, the shoreline is heavily developed to private residences, marinas and marine-related industries. Undeveloped areas are primarily in Federal and State ownerships, but a few parcels are either privately-owned or in Town ownership. Connetquot River State Park comprises approximately 4,000 acres (1,620 ha) in the south-central part of Islip Town. The 2,400 acre (972 ha) Federal Wertheim National Wildlife Refuge is adjacent to the privately-owned Southaven and the recently acquired (by the County) Robinson Duck Farm property in the Town of Brookhaven. The Carmans River estuary is situated within the Wertheim Refuge, while the headwaters of Yaphank Creek (a tributary of the Carmans River) are in private ownership within the Southaven parcel. Fire Island National Seashore is administered by the National Park Service.
V. GENERAL HABITAT DESCRIPTION: Great South Bay is the largest shallow saltwater bay in New York State and one of the largest in the study region. The bay is fed by a series of freshwater streams, the Connetquot and Carmans Rivers, and ocean water transported into the system via the Fire Island Inlet. Much of the bay is open water, but as the bay narrows at its western end near the Captree Bridge open water merges into an extensive series of tidal saltmarshes, saltmarsh islands and intertidal mud flats. These areas have developed on the protected northern edge of the barrier beach which separates Great South Bay and the mainland from the Atlantic Ocean. Less extensive tidal marshes and flats have developed on the bay side of Fire Island as well. Cordgrasses (Spartina alterniflora and S. patens) dominate the saltmarshes. Common reed (Phragmites australis) borders portions of the high marsh, grading to dense thickets of bayberry (Myrica pensylvanica) and poison ivy (Toxicodendron radicans) in drier areas. Bordering the Atlantic Ocean and in swales behind primary dunes, plants characteristic of stabilized older dune and coastal shrub communities are found. These include beachgrass (Ammophila breviligulata), beach plum (Prunus maritima), bayberry, winged sumac (Rhus copallina), beach heather (Hudsonia tomentosa), and Virginia creeper (Parthenocissus quinquefolia). The western barrier island from Captree to Jones Beach is divided roughly in half by a four lane east-west roadway, which separates northern saltmarsh from dune/swale plant communities on the southern portion of the barrier island.
VI. SIGNIFICANCE/UNIQUENESS OF AREA: The shallow waters of Great South Bay are a highly productive and regionally significant habitat for marine finfish, shellfish and wildlife. This productivity is due to the many saltmarshes and mud flats fringing both the mainland and the barrier islands, to the estuarine habitats around stream and river outlets on the mainland and to the sandy shoals and extensive eel grass (Zostera marina) beds which characterize open-water areas of the bay. As a result, Great South Bay has a commercial and recreational fishery of regional importance, affording essential habitat to many economically valuable finfish species that are estuarine-dependent during at least one stage in their life histories. Spawning and nursery grounds for weakfish (Cynoscion regalis), winter (Pseudopleuronectes americanus) and summer flounder (Paralichthys dentatus) and blackfish (Tautoga onitis) are present in the bay. Great South Bay is also a significant nursery area for young-of-the-year and 2nd year Hudson River striped bass (Morone saxatilis), for one and two year-old ocean-spawned bluefish (Pomatomus saltatrix) as well as supporting striped bass from older age classes during the summer. Adult striped bass and bluefish congregate in the deeper waters of Fire Island Inlet. Atlantic sturgeon (Acipenser oxyrhynchus) and American shad (Alosa sapidissima) and dozens of other species use the bay during migration. Forage fish such as killifish (Fundulus spp.), bay anchovy (Anchoa mitchilli) and Atlantic silverside (Menidia menidia) spawn in edge habitat around tidal marshes and islands. The bay also supports an economically significant shellfishery for hard-shelled clams (Mercenaria mercenaria) and is a major spawning, nursery and feeding area for blue crab (Callinectes sapidus).
The waters of Great South Bay support large concentrations of wintering waterfowl, particularly American black duck (Anas rubripes), brant (Branta bernicla), scaup (Aythya spp.), and red-breasted merganser (Mergus serrator). Harbor seals (Phoca vitulina) are frequently sighted in the bay during winter. In summer, the bay is an important feeding ground for least (Sterna antillarum), roseate (S. dougallii), a U.S. Endangered species, and common (S. hirundo) terns, ducks and herons, many of which nest locally. Nuisance species nesting in this area and of increasing concern include great black-backed (Larus marinus) and herring (Larus argentatus) gulls.
AREAS OF HIGHEST PRIORITY IN GREAT SOUTH BAY
1. Captree Islands to West Gilgo: This area includes all adjacent saltmarsh, associated islands and tidal flats in the western reaches of Great South Bay and, specifically, (a) the Captree Islands; (b) Sore Thumb; (c) Oak Island and Oak Beach; (d) Cedar Beach; (e) Gilgo Beach and Gilgo Island; and (f) Fire Island Inlet.
(a) Captree Islands (Towns of Islip and Babylon): The Captree Islands are an uninhabited and extensive expanse of tidal saltmarsh, mud flats, shallow pools and man-made ditches. Dominant marsh vegetation includes the cordgrasses and in drier areas common reed, poison ivy, groundsel-bush (Baccharis halimifolia) and marsh elder (Iva frutescens).
Several pairs of northern harrier (Circus cyaneus) nest in the dense common reed and poison ivy stands while seaside (Ammodramus maritimus) and sharptailed (A. caudacutus) sparrows and clapper rail (Rallus longirostris) nest on the marshes. The mosaic of tidal pools, marshes and mud flats provides a rich feeding area for wading birds, which include snowy and great egrets (Egretta thula and Casmerodius albus, respectively), tricolored and little blue herons (E. tricolor and E. caerulea, respectively), glossy ibis (Plegadis falcinellus) and American oystercatcher (Haematopus palliatus) in summer, and for shorebirds such as whimbrel (Numenius phaeopus), yellowlegs (Tringa spp.), and black-bellied plover (Pluvialis squatarola) during migration. Migrating raptors, including peregrine falcon (Falco peregrinus), a U.S. Endangered species, and merlin (Falco columbarius), use the Captree Islands as foraging habitat. The Islands have supported breeding least tern, marsh-nesting common tern and a large mixed heronry. The entire area is an important foraging area for these species as well. Short-eared owl (Asio flammeus) and northern harrier are common winter residents.
(b) Sore Thumb: This sandy beach area extending into Fire Island Inlet is important as a nesting ground for least tern and as a feeding/resting area for migratory shorebirds.
(c) Oak Island and Oak Beach: Oak Island is an inhabited marsh island with 54 homes built on land leased from the Town of Babylon. The island is accessible only by boat. Development is limited to the southernmost fringe of the 96 acre (39 ha) island. The remaining natural area is used as foraging habitat by northern harriers, wading birds and waterfowl.
Oak Beach is directly south of Oak Island, and is part of the main western barrier island. It is comprised of saltmarsh and dune-swale habitats and is in both Town of Babylon and New York State ownerships (Gilgo State Park). The Oak Beach marsh is extremely productive, and is distinctive as one of the few remaining unditched saltmarshes in the Northeast. Northern harriers may reach their highest State (and possibly Northeastern) breeding densities here. There is also evidence that seaside and sharptailed sparrow densities are higher at Oak Beach than on adjacent ditched marshes. This is the only known location on Long Island where black rail (Laterallus jamaicensis) are regularly heard or observed. The marsh also supports nesting American black duck and mallard (Anas platyrhynchos), Canada goose (Branta canadensis) and clapper rail, and is important as a spawning and/or nursery ground for weakfish, blue crab and forage fish species. The extensive tidal mud flats are known for supporting high concentrations of shorebirds during migration especially sanderling (Calidris alba), sandpipers, dowitchers (Limnodromus spp.) and plover, while the shallow tidal pools are used as a feeding area by resident and migratory waterfowl and wading birds.
(d) Cedar Beach: The second largest common tern nesting colony (over 4000 pairs in 1990) in the world is found behind the primary dunes at Cedar Beach. Ninety pairs of the U.S. Endangered roseate tern (the fourth largest colony in the Northeast) nested at this site in 1990 as well. The colony also supports three pairs of the U.S. Threatened piping plover (Charadrius melodus) and about 200 pairs of black skimmer (Rynchops niger). A pair of northern harriers nests adjacent to the nearby saltmarsh, and both harriers and short-eared owls use these marshes and dunes as foraging areas during winter. Cedar Beach is an area used by large numbers of nesting Northern diamondback terrapins (Malaclemys terrapin) which also feed and winter in the tidal areas north of the tern colony. A population of sea-beach pigweed (Amaranthus pumilis), a candidate for listing under the U.S. Endangered Species Act, occurs at Cedar Beach.
(e) Gilgo Beach and Gilgo Island: Gilgo Beach is one of the most productive least tern nesting colonies on Long Island. This area also supports breeding piping plover, seaside sparrow and northern harrier, as well as high concentrations of nesting Northern diamondback terrapin.
(f) Fire Island Inlet: Fire Island Inlet is critical to maintaining the high productivity levels of Great South Bay. Through daily tidal flushing the Inlet maintains the necessary conditions, especially those related to salinity and water quality, that foster the diversity of marine and wildlife species in the bay ecosystem. Specific salinity levels are crucial to the continued production of hard-shelled clams and may be essential to spawning weakfish and other finfish. The Inlet is also habitat for adult finfish of commercial and recreational value, especially striped bass and bluefish which congregate in areas of deep water, and the plankton-eating American sandlance (Ammodytes americanus), important as a forage base for both predatory fish and roseate terns. The Inlet is the most important foraging area for roseate terns on western Long Island.
2. Connetquot River Estuary: The Connetquot River is part of a 4500 acre (1823 ha) undeveloped coastal watershed system, unique in this urbanized location, that has been designated by New York State as a Wild, Scenic and Recreational River. The river is fed by several natural cold-water streams originating from groundwater sources. The estuarine portion of the watershed, from the mouth of the river at its outlet in Great South Bay to tidewater, is approximately 2 miles (3 km) in length, and includes adjacent State-owned tidal wetlands.
Waterfowl in great numbers use the Connetquot River estuary as a major wintering area and as a stopover point during migration. The most abundant waterfowl include American black duck, mallard, scaup, canvasback (Aythya valisineria), redhead (Aythya americana), bufflehead (Bucephala albeola) and Canada goose, among others. The large open and shallow Connetquot River estuary provides essential habitat for a diversity of fish and wildlife species. Of particular significance is the estuary's importance as a nursery ground for yearling striped bass and bluefish which concentrate to feed in the tidewater areas before commencing coastal migration. Unusual for Long Island, anadromous species such as alewife (Alosa pseudoharengus) and white perch (Morone americana) are possible spawners. The estuary supports a sea-run brown trout (Salmo trutta) fishery, and weakfish congregate to spawn in the sandy shallow of nearby Heckscher Flats.
3. Champlin Creek and Orowoc Creek: Champlin Creek is a relatively undisturbed, clean, freshwater coastal stream. The upper portions of Champlin Creek provide habitat conditions suitable for natural reproduction by one of only six known wild populations of brook trout (Salvelinus fontinalis) on Long Island. At its southern terminus near Great South Bay the stream enters Seatuck National Wildlife Refuge, and ultimately a system of freshwater, brackish and tidal marshes and ditches. Like other coastal streams along the shoreline, the interface of fresh and salt water provides rich spawning and nursery habitats for commercially valuable marine species, including white perch and yearling striped bass and bluefish.
Orowoc Creek is a freshwater coastal stream harboring a locally rare population of naturally-reproducing brook trout. The upper watershed of Orowoc Creek (approximately 1.5 miles (2 km) north of the bay) remains relatively undisturbed and is under consideration for public ownership through Town and/or County purchase. Many species of birds, reptiles and amphibians unusual for an urbanized area inhabit the wetlands and riparian woodlands. These include wood duck (Aix sponsa), DeKay's brown snake (Storeria dekayi), box turtle (Terrapene spp.) and numerous songbirds. A sphagnum bog harboring sundews (Drosera spp.), cranberry (Vaccinium spp.), several species of orchid and other plants of special botanical interest also occurs along the Orowoc. A nearby shallow pond contains mermaid weed (Proserpinaca palustris), an uncommon species in the region. Redfin pickerel (Esox americanus) are also found in this part of the Orowoc.
4. Lower Carmans River Watershed: This area includes (a) the Carmans River estuary, (b) Yaphank Creek, (c) Southaven Properties, and (d) the former "Robinson Duck Farm" property (now a part of the Suffolk County Park System).
(a) Carmans River Estuary (Town of Brookhaven): The Carmans River estuary is one of four major riverine ecosystems on Long Island, and has been designated by New York State as a "Wild, Scenic and Recreational River." The tidal river begins approximately 2 miles (3 km) north of Bellport Bay (part of Great South Bay) just below the Southaven Dam and is primarily within the 2400 acre (972 ha) Wertheim National Wildlife Refuge. Extensive and undeveloped tidal wetlands on both sides of the river provide outstanding habitat for a great diversity of fish and wildlife species.
The Carmans River estuary is one of the most significant nursery areas for yearling striped bass in Great South Bay. Juvenile bluefish are also found in abundance. Both species may spend a year or more in tidal portions of the river before commencing coastal migration. Alewife, sea-run brown trout and white perch spawn in the estuary, which also provides important nursery habitat for these species. The commercially and recreationally valuable blue crab spawns around the nutrient-rich saltmarshes fringing the estuary. Forage fish such as killifish and Atlantic silverside also use the shallow waters of tidal wetland areas as spawning and nursery grounds.
The estuary provides regionally important wintering habitat for high concentrations of waterfowl including canvasback, hooded merganser (Lophodytes cucullatus), redhead, northern shoveler (Anas clypeata), northern pintail (Anas acuta), gadwall (Anas strepera), American wigeon (Anas americana), American black duck, mallard, red-breasted merganser, scaup, and bufflehead. Other species of birds inhabiting the wetlands bordering the river are breeding osprey (Pandion haliaetus), sharp-tailed sparrow, seaside sparrow and clapper rail, migrating and wintering northern harriers, peregrine falcons and other raptors which hunt over the tidal marshes during migration.
(b) Yaphank Creek: Yaphank Creek is a completely undisturbed tributary of the Carmans River. At the creek's headwaters is an extensive emergent freshwater marsh, a regionally rare natural community, in excellent condition. Acidic bog vegetation, including sphagnum moss, round-leaved sundew (Drosera rotundifolia), bladderwort (Utricularia spp.) and gerardia (Agalinis spp.) specifically adapted to live in the low-nutrient waters characteristic of sandy coastal plain soils, borders the marsh. The fast-moving headwaters of upper Yaphank Creek are a spawning ground for one of Long Island's six naturally-reproducing populations of native brook trout as well as for redfin pickerel.
Upper Yaphank Creek provides nesting and foraging habitat for a diversity of avian species including osprey, wood duck, American black duck, mallard, gadwall and eastern bluebird. Northern harriers forage over the wetlands and associated sphagnum bog. Yaphank Creek is one of only four known New York State locales where the eastern mud turtle (Kinosternon subrubrum) breeds in the brackish marshes and one of the few Long Island habitats suitable for the declining northern water snake (Nerodia sipedon). Lower Yaphank Creek also supports yearling striped bass and is a spawning area for white perch and several forage fish species.
(c) Southaven Properties: Southaven Properties is a privately-owned, ecologically diverse parcel bordering Wertheim National Wildlife Refuge on the western and northern edges, and is located within the Carmans River scenic corridor. This 128 acre (52 ha) site encompasses three broad habitat types consisting of oak-pine-hickory woodlands, old fields and wetlands/aquatic areas. The western portion of the property straddles the undisturbed headwaters of Yaphank Creek, a tributary of the Carmans River. The creek is fed by two small groundwater streams flowing through the Southaven Properties. The high wildlife values associated with this parcel are related to the several habitat types which occur here. Wildlife species found here include nesting osprey, wood duck, American black duck, mallard and eastern bluebird. Migratory species of concern using the site are peregrine falcon and northern harrier, as well as many species of migratory neotropical songbirds presently of international conservation concern.
(d) Robinson Duck Farm: The former Robinson Duck Farm site has been recently acquired by Suffolk County with the intent of maintaining it as a greenbelt park. A major value of this property is its critical positioning relative to both the estuary and to the Wertheim National Wildlife Refuge which it directly borders on the western boundary. The parcel was originally included as part of the Refuge design but never incorporated because it was privately owned. Ecologically, the site is recovering from past intensive use as a duck farm. Large open areas are in varying stages of succession. Part of the site has recently been planted to corn. Common reed has invaded around former duck ponds and other wet areas. Along the river bank, a fringe of the original moist woodland remains, characterized by tupelo (Nyssa sylvatica) and red maple (Acer rubrum). Although disturbed, the site supports waterfowl, wading birds, harriers and shorebirds and provides habitat contiguous with the Wertheim National Wildlife Refuge for terrestrial wildlife including white-tailed deer (Odocoileus virginianus).
5. Fire Island National Seashore Wilderness Area: This area includes the barrier island (Fire Island) and associated tidal wetlands and intertidal mudflats between Watch Hill/Davis Park and the Smith Point Park Bridge. The sandy beaches and dunelands of the barrier island in the eastern reach of the Great South Bay provide significant nesting habitat for least tern and piping plover. The area is also important for migrating and wintering northern harrier (possible breeders), short-eared owl and snowy owl, all of which forage over swales and the extensive salt marshes fringing the barrier island on its northern edge. These tidal marshes and associated mudflats provide resting and feeding habitat for thousands of migratory shorebirds, especially sandpipers, sanderling, plover and dowitcher during both spring and fall passages.
This portion of the barrier island supports a major breeding population of the eastern mud turtle and is one of the few Long Island locations where black rail have been sighted. Clapper rail and seaside sparrow are common nesters in the saltmarshes. The productive bay waters of the Fire Island National Seashore Wilderness Area are known for high concentrations of wintering waterfowl, especially scaup, pied-billed grebe (Podilymbus podiceps), American black duck and red-breasted merganser, which gather to feed and rest there. Adult striped bass and bluefish congregate in the deeper waters of the eastern bay around the Smith Point Bridge where forage species such as menhaden (Brevoortia tyrannus) are plentiful.
VII. THREATS: Although many of the remaining undeveloped lands around Great South Bay are already publicly owned, recreational pressure from a growing human population is strong. This is especially problematic on the western barrier island where Town-owned lands of wildlife significance have repeatedly been opened to increased public access and more intensive use.
Elimination or alteration of tidal marsh, intertidal areas and dune habitat, degradation of water quality and increased human presence near breeding grounds can create negative and irreparable impacts to terrestrial and marine wildlife species, especially those already in decline such as U.S. Threatened or Endangered species. Overexploitation of marine resources has already resulted in population declines for economically valuable finfish (e.g. weakfish) and hard-shelled clams in Long Island waters. Degradation of water quality, especially by non-point source runoff, is of mounting concern and has adversely impacted American oyster (Crassostrea virginica) and bay scallop (Aequipecten irradians) industries and has been implicated in the decline of the flounder fishery. Increased runoff and nitrogen loading to ground and surface water from roads and septic systems would adversely impact water quality and vegetation in the area, as would continuing discharges of pesticides and fertilizers, altering spawning and nursery habitats to the detriment of the many marine species dependent on these systems.
Other wildlife species of concern, including piping plover, least, common and roseate terns and northern harrier are undergoing loss or disturbance to critical nesting habitats. Development of remaining private lands in sensitive areas such as the Carmans River estuary would eliminate or disturb wetland and forest habitat with potentially devastating consequences to the ecology of the river, Great South Bay and on rare or uncommon fauna and flora occurring in these habitats. Development of Southaven Properties would have an irreversible negative impact on the Wertheim National Wildlife Refuge, fragmenting wildlife habitat now contiguous with Refuge holdings, eliminating species sensitive to human disturbance, increasing predation on Refuge wildlife by domestic cats and dogs, and increasing vandalism within Refuge confines.
VIII. CONSERVATION CONSIDERATIONS: The entire Great South Bay estuary, including the bay waters, barrier beaches, tidal marshes and coastal streams and rivers identified, should be considered for recognition or designation as a National Estuarine Research Reserve or as Wetlands of International Importance under the Ramsar Convention. This would be especially beneficial to those publicly-owned lands which are now primarily managed to accommodate human recreation, with little attention afforded protection and/or enhancement of wildlife habitats. There is an excellent opportunity to protect and enhance the value of Wertheim National Wildlife Refuge by adding Southaven Properties to Refuge holdings, thus completing the design originally proposed and preserving the integrity of the Refuge. The fact that a significant number of acres remain vulnerable to degradation, including those that are publicly-owned, indicates a need for further protection. There are extensive areas of degraded tidal marsh along the south shore of mainland Long Island that have been identified for restoration as American black duck habitat by the North American Waterfowl Management Plan-Atlantic Coast Joint Venture.
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