Northeast Coastal Areas Study
Significant Coastal Habitats
Site 39 (MA)
I. SITE NAME: Muskeget and Tuckernuck Islands and Muskeget Channel
II. LOCATION: Muskeget and Tuckernuck Islands are located just west of Nantucket Island and south of Cape Cod. Muskeget Channel is a shallow water channel running between the open Atlantic Ocean and Nantucket Sound and lying between Nantucket Island and Martha's Vineyard.
USGS 7.5 MIN QUAD: Tuckernuck Island, Mass 41070-33
USGS 30x60 MIN QUAD: Martha's Vineyard 41070-A1
III. GENERAL BOUNDARY: The general boundary for this area is outlined on the accompanying map, and includes both islands in their entirety and the nearshore shallow water shoals surrounding them. The main channel area extends from west of Muskeget Island east to Chappaquiddick Island, Martha's Vineyard.
IV. OWNERSHIP/PROTECTED STATUS: Both islands are predominately in private ownership. Parts of Muskeget Island are owned by the Town of Nantucket. There are approximately 30-35 seasonally occupied dwellings on Tuckernuck Island.
V. GENERAL HABITAT DESCRIPTION: Muskeget Channel is a shallow water area of temporary shoals and permanent islands. Muskeget and Tuckernuck Islands were originally formed by the terminal moraine of the last glacial episode. Tuckernuck still retains remnants of the moraine as low hills, but the southern half of the island consists of outwash plains characterized by coastal heathland, a globally restricted and endangered plant community. This community occurs only from Long Island, NY, to Cape Cod, MA. Dominant species include little bluestem (Schizachyrium scoparium), bearberry (Arctostaphylos uva-ursi), and low ericaceous shrubs. There are extensive areas of scrub oak (Quercus ilicifolia) vegetation up to 15 feet (5 m) in height with pitch pine (Pinus rigida), black huckleberry (Gaylussacia baccata), bayberry (Myrica pensylvanica), beach plum (Prunus maritima) and sweet pepperbush (Clethra alnifolia). Red maple (Acer rubrum) and black gum (Nyssa sylvatica) occur in kettlehole swamps. Muskeget Island has lost its morainal hills and is now composed of marine-worked sands and gravels. The dominant plants are beachgrass (Ammophila breviligulata), seaside goldenrod (Solidago sempervirens), poison ivy (Toxicodendron radicans), bayberry, beach plum, saltspray rose (Rosa rugosa) and other shrubs on the stabilized dunes. There are a few small freshwater marshes and a saltmarsh dominated by cordgrass (Spartina alterniflora).
VI. SIGNIFICANCE/UNIQUENESS OF AREA: The shallow waters and shoals of Muskeget Channel and the areas surrounding the islands are highly productive for marine fish, shellfish, and eelgrass (Zostera marina), providing rich feeding grounds for terns and gulls in summer and sea ducks in winter. The largest concentration of oldsquaws (Clangula hyemalis) in the western Atlantic occurs here (counts of over 150,000 have been recorded), along with thousands of common eiders (Somateria mollissima) and three species of scoter (Melanitta spp.). In late summer a thousand or more roseate terns (Sterna dougallii), a U.S. Endangered species, feed here in preparation for their southward migration. Muskeget Island is the only known locality for the Muskeget beach vole, a taxon considered either a full species (Microtus breweri) or a subspecies of the meadow vole (M. pennsylvanicus). It is currently a candidate for listing under the U.S. Endangered Species Act. Extensive sandspits on Muskeget, Tuckernuck, and Skiff Islands (west side of Muskeget Channel off Martha's Vineyard) support rare plants and are favored haulout points for large numbers of harbor and gray seals (Phoca vitulina and Halichoerus grypus, respectively). One of only two U.S. breeding locations for gray seal is on Muskeget and the island also supports major herring gull (Larus argentatus) and great black-backed gull (Larus atricilla) colonies. These islands support many State and Federally rare species including: Nantucket shadbush (Amelanchier nantucketensis), a candidate species for listing under the Act, several pairs of short-eared owl (Asio flammeus), piping plover (Charadrius melodus), a U.S. Threatened species, least tern (Sterna antillarum), northern harrier (Circus cyaneus) and common tern (Sterna hirundo). Muskeget Island is a designated National Natural Landmark, due primarily to the presence of breeding gray seals and beach voles.
Of historical note, because of its remoteness and isolation from the mainland as well as the larger islands of Nantucket and Martha's Vineyard, Muskeget Island was a major site occupied by nesting common and roseate terns which allowed them to escape and survive the ravages of the feather trade that decimated bird colonies elsewhere throughout the region around the turn of the century. Having survived the feather trade, the tern colony was later displaced by a major laughing gull (Larus atricilla) colony. Not long afterwards, the first breeding colony of herring gulls in the region was established on this island and soon displaced the laughing gulls until they, in turn, were displaced by great black-backed gulls.
VII. THREATS: Threats include commercial fisheries, natural resource extraction, potential land development, oil spills and recreational boating.
VIII. CONSERVATION CONSIDERATIONS: Appropriate levels of Federal protection and management are necessary to protect the important waterfowl, colonial nesting birds and pinniped values of this area. Beach habitats of nesting piping plovers and terns are highly vulnerable to human-related disturbances and measures should be taken to ensure that these habitats are protected from human and predator intrusions during the critical nesting season (mid-April to August). Efforts should be made to identify and implement objectives and tasks outlined in the piping plover recovery plan that could be applied to nesting beaches on these islands. Gull removal should be considered if the growing gull populations are determined to be a threat to the recovery or maintenance of piping plover and tern colonies in this area. Opportunities should be sought to develop cooperative management and conservation agreements between State and Federal resource agencies and private landowners on the islands, particularly Tuckernuck Island, and also to inform other agencies such as the Corps of Engineers and the Coast Guard of the high ecological value of this area and the need to consider these values in any dredging operations, regulation or approval of shipping lanes or oil spill contingency plans.
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