Freshwater Mussel Restoration
In the early morning of August 27, 1998, a tanker truck overturned on U.S. Route 460 in Tazewell County, Virginia releasing 1,350 gallons of a rubber accelerant into an unnamed tributary of the Clinch River. The spill material quickly turned the Clinch River milky-white and caused a major kill of aquatic life for over seven miles downstream. It was estimated that 18,000 mussels and untold numbers of fish, snails, and other aquatic organisms perished in the event. The ages of some of the mussels killed were estimated to be over 80 years.
The Clinch River has one the most diverse fish and mussel faunas of any river in North America. Of the 300 species historically documented in the U.S., 20% are known from the Clinch River in Virginia and Tennessee. Prior to the spill, the Clinch River at the town of Cedar Bluff had the most diverse mussel assemblage in the upper reaches of the river. At least 16 mussel species, including 3 federally endangered species, occurred there.
The most significant loss was that of approximately 750 individuals of three federally endangered mussel species, the tan riffleshell, purple bean, and rough rabbitsfoot. In fact, the spill is considered the most significant kill of endangered species in the history of the U.S. Endangered Species Act of 1973. Furthermore, the last viable population of tan riffleshell in the Tennessee River basin occurred in the Clinch River from at Cedar Bluff, and in the lower reach of Indian Creek. The loss of the Clinch River population was a major setback to the recovery of this species. .Endangered species recovery is contingent upon protecting and enhancing the remaining populations in Indian Creek. Progeny produced from remaining stocks in Indian Creek will be used to replenish the Clinch River.
To recover damages for the lost resource, the Department of Interior (DOI) entered into a consent decree with the U.S. District Court of the Western District of Virginia on April 7, 2003. The consent decree required the trucking company to pay $3.8 million to the Department of Interior Natural Resource Damage and Assessment and Restoration (NRDAR) fund. Monies from this fund are to be used to "plan, perform, monitor and oversee native, freshwater mussel restoration projects with in the Clinch River watershed" over a 12-year period. Specific actions for restoration include freshwater mussel propagation, public outreach and education, riparian area protection, and restoration monitoring.
On October 24, 1996, a coal mine slurry impoundment in Lee County, Virginia broke through an abandoned mine works, releasing 5.8 million gallons of coal waste slurry. The waste spilled into Gin Creek, then moved on to Straight Creek and the North Fork Powell River. The nine day impact resulted in the contamination of 50 miles of stream, including critical habitats of two federally listed fish species and nine endangered mussel species.
On March 5, 2001 the DOI entered into a consent decree with the U.S. District Court of the Western District of Virginia to recover damages for the lost resources. This consent decree required the coal company to pay $2.45 million to the NRDAR fund. Monies from this fund are to be used for "reimbursement of past natural resource damage assessment costs, and restoration, replacement or acquisition of endangered and threatened fishes and mussels located in the Powell River and its watershed... or for restoration, planning, implementation, oversight and monitoring."
Presently, the AWCC is working closely with the FMCC to understand the complexities of freshwater mussel biology and ecology. The ability to cultivate freshwater mussels has taken decades of research by individuals like Dr. Richard Neves and his students. Most research funding is provided by the U.S. Fish and Wildlife Service (USFWS), the U.S. Geological Survey (USGS), the Virginia Department of Game and Inland Fisheries (VDGIF) and other state partners. New knowledge of life history traits, dietary needs and habitat requirements lead to improved culture techniques, giving biologists the ability to propagate and grow freshwater mussels under controlled laboratory conditions. Mussels produced in this manner can then be used to replenish and recover wild stocks.
The Department has undertaken a monitoring program to assess the status of freshwater mussel communities in Southwest Virginia as well as gauging the success of recovery efforts. A large scale quantitative survey is conducted each year using quadrat and snorkeling samples to characterize all mussel species and density at monitoring sites. Survey sites are visited on a 5-year cycle. Comparing results of separate surveys will allow biologists to determine if populations are increasing, decreasing or remaining stable. Results of previous surveys are linked below.
Resources for More Information
- Video: Endangered Mussels Released into the Clinch River, Largest Release in Eastern US
- Virginia Department of Game and Inland Fisheries Mussel Survey Reports
- Aquatic Wildlife Conservation Center's propagation and release summaries
- Regaining Our Freshwater Mussel Heritage (PDF - 1.7 MB)
- Virginia Freshwater Mussel Restoration Strategy: Upper Tennessee River Basin (PDF)
- Freshwater Mussels
- A Shocking Stream (PDF)
- U.S. Fish and Wildlife Service