Status of Snail Darters (Percina tanasi) in the Lower French Broad River, Tennessee

Edwin M. Scott, Jr.
Tennessee Valley Authority, 17 Ridgeway Road, Norris, Tennessee 37828. Phone (423) 632-1782, fax (423) 632-1693, email emscott@tva.gov.

TVA has monitored federally threatened snail darters in the French Broad River below Douglas Dam since 1997, concurrent with modernization of the hydro turbines at the dam. This population resulted from snail darter transplants into the lower Holston River, 1978-79. In 1999, following replacement of two turbines and their subsequent operation, the snail darter population is healthy and may in fact be expanding. Adult snail darters were found at all three sites under study, spanning over 20 river miles. While the health of snail darters and improvements in the fish community in general are attributed to TVA's Reservoir Releases Improvement program, which provided minimum flows and reaerated discharges at Douglas Dam since 1993, the operation of the two new turbines has apparently had no negative effects. Challenges facing snail darters in the lower French Broad river include residential development, nonpoint source pollution, contamination from the Little Pigeon River, excessive aquatic macrophytes, sand dredging, and potentially, exotic fish species. A critical research need in conserving this population is determination of its early life history.