With 77 species, the mussel fauna of Virginia is one of the most diverse in the United States. Fifty-four species or ~70% of the state’s mussel fauna occurs in the rivers of the upper Tennessee River basin, especially in the Clinch and Powell rivers of southwestern Virginia. An additional 23 species reside in rivers of the Atlantic Slope, including the Potomac, Rappahannock, York, James and Chowan basins, and in the New River, a major tributary to the Ohio River. A total of 39 species or 51% of Virginia’s mussel fauna is listed as federally endangered, state endangered or state threatened. Excess sediment, nutrients and various types of pollutants entering streams from agriculture and industries are the main drivers of imperilment. Freshwater mussels reproduce in a specialized way, one that requires a fish to serve as a host to their larvae, called glochidia, allowing the larvae to metamorphose to the juvenile stage. This extra step in their life cycle uniquely defines mussels among bivalve mollusks worldwide, in freshwater or marine environments, and adds significant complexity to their reproductive biology. Further, they utilize “lures” that mimic prey of fishes to attract their host. Mussels rely on their fish host to provide them with long-distance dispersal and nutrition while they are glochidia, which are small (
Jones, Jess W.
"Freshwater Mussels of Virginia (Bivalvia: Unionidae): An Introduction to Their Life History, Status and Conservation,"
Virginia Journal of Science: Vol. 66
, Article 6.
Available at: http://digitalcommons.odu.edu/vjs/vol66/iss3/6