Elephant-ear (Elliptio crassidens crassidens)
Nearly 78 percent of all North American freshwater mussel species have rapidly declining populations, and the elephant-ear (Elliptio crassidens crassidens) is no exception. The drop in mussel populations has been attributed to point and non-point source water pollution, improper gravel mining and damming of natural streams.
Mussels feed by filtering matter from the water and can tolerate only low levels of pollutants. Pesticides and heavy metals accumulate in their shells, which scientists can examine to determine water pollution levels. The decline of the elephant-ear and other mussels warns us that our water quality is also in decline.
-- Amy Seaveter, endangered species coordinator