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Tennessee Wildlife Resources Agency
Ellington Agricultural Center
440 Hogan Road
Nashville, TN 37220
(615) 781-6500
Endangered Alabama Lampmussel Returns to the Elk River

Like many Tennessee drainage rivers, the Elk River once supported a highly diverse mussel fauna of at least 61 species (this level of diversity now persists only in the Duck and Clinch rivers). The Elk River originates on the western edge of the Cumberland Plateau in south-central Tennessee and flows approximately 202 miles westward before joining the Tennessee River in northern Alabama and has two hydro-electric dams.

For many decades subsequent to dam construction, cold water releases from the reservoirs of Tennessee Valley Authority’s (TVA) Tim’s Ford Dam and Arnold Engineering Design Company’s Elk River Dam affected freshwater mussel populations. But in 2005, TVA initiated formal consultation with the U.S. Fish and Wildlife Service (USFWS) regarding routine operation and maintenance of TVA’s water control structures. An agreement concluded in 2006 resulted in a TVA-managed flow regime that more closely simulates natural flows and water temperatures in the 100 miles of river downstream from the dam.

Since 2007, TVA has modified water releases from Tim’s Ford Dam to promote recovery of federally listed mussels and fish while continuing to support an artificial trout fishery and numerous demands for water. Although relatively few mussels remain in the river below the dam, populations downstream of Fayetteville, TN and the Harms Mill low-head dam have shown notable improvements since 2008.

These improvements encouraged TWRA and Alabama Department of Wildlife and Freshwater Fisheries (ADWFF) to work cooperatively in reintroducing hatchery-reared individuals of the extremely rare and federally endangered Alabama Lampmussel (Lampsilis virescens) into the lower Elk River.

Endemic to the Tennessee River system, the Alabama Lampmussel historically occurred from its headwaters downstream to Muscle Shoals, AL, but it has now been eliminated from over 95% of its former range. It once occurred in small creeks to large rivers; however, at present it only persists in a small section of the Emory River, Morgan County, TN, and in the upper reaches of the Paint Rock River system, Jackson County, AL.

The mussel reintroduction process begins when ADWFF collects female Alabama Lampmussels from the Paint Rock river system to produce juvenile mussels at its Alabama Aquatic Biodiversity Center. Microscopic packman-shaped parasitic larvae called glochidia are extracted from the female mussel’s gills and inoculated onto the gills of its host fish species (rockbass, largemouth and redeye bass). After about one month, the larval mussels transform into juveniles. Alabama Aquatic Biodiversity Center staff under the direction of Dr. Paul Johnson collect the juvenile mussels and grow them in pond culture systems for a year or more until they are large enough to be released.

Don Hubbs, TWRA Mollusk Recovery Coordinator, tested survival of reintroduced mussels in the river using a mussel silo, which holds the mussels and allows them to filter feed on algae and bacteria present in the river water. After one month, he retrieved the silo and recorded a 100 % survival rate. Results of this trial in 2010 led TWRA and ADWFF to initiate a full reintroduction plan.

As of fall 2017, the agencies had stocked 10,462 Alabama Lampmussels into the Tennessee portion of the Elk River. The largest stocking to date occurred in summer 2017 when TWRA (Don Hubbs and Bobby Brown), AWDFF (Dr. Paul Johnson and Jeff Garner) and USFWS (Stephanie Chance and Sarah Harrison) released 8,000 juvenile Alabama Lampmussels, helping to bring this rare animal back from the brink of extinction and securing its future.

Download a fact sheet on this mussel reintroduction project to see some happy biologists at work.


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