Native Fresh-Water Mussels
There are 10 species of native freshwater mussels in the state of New Hampshire. Some species, such as the eastern Elliptio, are common and widespread in our rivers, ponds and lakes. Others, particularly the brook floater and dwarf wedge mussel, have reached population numbers so low that they are now considered endangered. Eastern pond mussels are currently a species of special concern and are restricted to a handful of ponds and lakes in southeastern New Hampshire.
Mussels are considered good environmental indicators because they are sensitive to water quality and habitat degradation. In fact, mussels can indicate a water quality issue long before even the most sophisticated scientific equipment can detect a problem. (NH Fish and Game)