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Document Type

Article

DOI

10.25778/3baj-mq15

Abstract

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 (<0.5 mm) ecto-parasites that attach and encyst on the gills and fins of fishes, typically taking weeks to months to metamorphose, excyst and then drop-away as similar-sized juveniles to the stream bottom where they grow into adults. Adult mussels are mostly sedentary animals living in the benthos, i.e., the bottom of streams and lakes, typically in mixed substrates of sand, gravel and fine sediments. Mussels generally filter suspended organic particles <20 µm from the water column but can also filter deposited particles through the shell-gap when burrowed in the benthos. Further, the adults of most species are long-lived, regularly living 25-50 years or longer in freshwater environments throughout North America. Conservation of freshwater mussels in Virginia will require citizens, nongovernmental organizations, local, county, state and federal governments to apply their resources to five main areas: (1) water quality monitoring and regulation enforcement, (2) restoration of stream habitat, (3) restoration of mussel populations, (4) educating the public about the importance and status of mussels, and (5) monitoring and research to understand why mussels are declining and what are the best ways to protect them. Sustained long-term efforts in these five areas offers the greatest potential to conserve freshwater mussels throughout Virginia.

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