DistributionRead full entry
Global Range: (20,000-200,000 square km (about 8000-80,000 square miles)) This species has a large geographic range, from Nova Scotia to Georgia in Atlantic drainages, and in St. Lawrence River system westward to Ontario. While many historic occurrences are extirpated, the species still occurs in numbers in a few places, and the wide range is actually represented by several disjunct populations. Some sites have problematic identifications. In Canada, it is currently known from only two localities: Cape Breton Island, Nova Scotia, and Fredericton, New Brunswick (COSEWIC, 2004). In the Atlantic Slope, it occurs east of the Appalachian Mountains from the Sydney River, Nova Scotia, to the Ogeechee River, Georgia (likely historical only- see Sukkestad et al., 2006), South Carolina, North Carolina, Virginia, Maryland, Delaware, Pennsylvania, New Jersey, New York, Connecticut (thought extirpated but barely hanging on in the lower Connecticut River), Massachusetts, Maine, New Brunswick, and Nova Scotia. Recently, the species has contracted its range in most of the southern states and populations are in decline and disappearing nearly everywhere. Populations persist in the lower Saint John River and tributaries, New Brunswick, despite range contraction over the past century (Sabine et al., 2004).