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Dwarf wedgemussel Listed: 3/14/1990 Status since listing: Stable The dwarf wedgemussel (Alasmidonta heterodon) lives in muddy sand, sand, clay and gravel bottoms in creeks and rivers of various sizes [1]. It requires areas of slow to moderate current, good water quality, and low silt deposition. It formerly occurred in 15 major Atlantic slope drainages from New Brunswick to North Carolina. By 1993, it was known from only 20 locations in eight drainages in New Hampshire, Vermont, Connecticut, New York, Maryland, Virginia and North Carolina. Due to increased survey effort, it was known from over 80 sites as of 2004, but only about 16 were believed to support reproducing populations, while at least 31 were based on observations of fewer than five individuals or solely on spent shells [2]. The rediscoveries have expanded the current state range to include Massachusetts, New Jersey and Pennsylvania. The species population trend since 1990 can not be quantified due to the absence of systematic surveys, but is believed to be relatively stable overall [3]. The New Hampshire and Vermont populations are stable with hundreds of thousands of individuals in the Connecticut River mainstem in the New Hampshire section; the Massachusetts, Connecticut, New York, New Jersey, and Pennsylvania populations appear to be stable; it is rare and probably declining in Virginia; and declining (e.g. Swift River watershed) or stable (e.g. Tar River) in North Carolina rivers. [1] U.S. Fish and Wildlife Service. 1993. Dwarf Wedgemussel (Alasmidonta heterodon) Recovery Plan. Hadley, MA. |
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