WASHINGTON (CN) - Two freshwater mussel species, the spectaclecase and sheepnose, are endangered throughout their range, according to a listing decision by the U.S. Fish and Wildlife Service.
Both species are threatened by habitat degradation resulting from dams, mining and other alterations to the rivers they call home and have seen declines in populations of up to 70 percent in the case of the sheepnose and 60 percent for the spectaclecase, according to the agency.
The USFWS originally proposed listing these two species as endangered in October 2011.
The spectaclecase mussel generally inhabits large rivers. Based on historical and current data, the spectaclecase has declined significantly rangewide and is now found only in 20 of 44 streams.
The sheepnose mussel is a larger-stream species found primarily in shallow shoal habitats. The sheepnose is now found in 25 streams compared to 77 streams, historically.
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