Snail darter

Most new species are discovered, then described in the scientific literature with little fanfare, and most are then known only to a relatively small group of specialists. This was not the case with the snail darter (Percina tanasi ), a small member of the freshwater fish family of perches, Percidae. The snail darter's discovery cast it in the limelight of a highly controversial, environmental battle over the impoundment of the Little Tennessee River by the Tellico Dam . Because its discovery coincided with the enactment of the Endangered Species Act , its only known habitat was the free-flowing channel of the Little Tennessee River, and it was perceived as a means of successfully challenging the completion of this Tennessee Valley Authority project.

Two ichthyologists at the University of Tennessee, Drs. David Etnier and Robert Stiles, discovered the snail darter in the Little Tennessee River in August of 1973. After catching several specimens of these three-inch creatures, they returned to Knoxville to examine their find. By that fall, after careful comparison with other members of the genus, it was clear that they had found a new species of fish.

Because this darter was not known from any other location, Dr. Etnier submitted a status report on the species to the U.S. Fish and Wildlife Service the following year. The darter's existence was being threatened by the completion of the Tellico Dam, which would ultimately eliminate the free-flowing, clear, riverine habitat needed for its survival. The darter was recommended for listing as an endangered species in 1975, and in January 1976 its official scientific description was published. It was now the snail darter.

The notoriety this fish was beginning to receive did not go unnoticed by the TVA. They began transplanting snail darters to the Hiwassee River in 1975 and, by early 1976, had moved over 700 to the new location. All of this was done in secrecy, neither the Fish and Wildlife Service nor the appropriate Tennessee state agencies were notified. When the snail darter was designated an endangered species, the court battles began. Injunctions to halt completion of the Tellico Dam were granted and overturned all the way to the Supreme Court, where the justices ruled in favor of the snail darter. However, the High Court left an opening for the U.S. Congress to step in and exempt Tellico Dam from the Endangered Species Act. That is just what Congress did, and in January 1980 the gates closed and the reservoir behind Tellico Dam began to fill, thus sealing the fate of the Little Tennessee River and its darter population.

An additional population of snail darters was discovered in the Hiwassee River, and this population seems to be thriving. The snail darter, so named because of the principle component of its diet, continues its existence and is thought to number upwards of 100,000. It was moved from the endangered listing to one of threatened by the Department of the Interior (DOI) in 1984. Dr. Etnier believes that now the snail darter should be removed from the list of threatened species. The species' scientific name, Percina tanasi, is in reference to the ancient Cherokee Village and Native American burial ground of Tanasi, from which the state got its name, and which, now, lies at the bottom of Tellico's reservoir.

Snail darters live for an average of two years, with a maximum recorded longevity of four years. These darters reach sexual maturity at one year and migrate from their downstream, slackwater habitat to the sand and gravel shoals upstream, where they will eventually spawn. These clear, shallow shoal areas represent the habitat needed by the snail darters and their mollusk prey for survival.

[Eugene C. Beckham ]

RESOURCES

BOOKS

Ono, R., J. Williams, and A. Wagner. Vanishing Fishes of North America. Washington, DC: Stone Wall Press, 1983.

Page, L. Handbook of Darters. Neptune City, NJ: TFH Publications, 1983.

PERIODICALS

Etnier, D. "Percina (Imostoma) tanasi, A New Percid Fish From the Little Tennessee River, Tennessee." Proceedings of the Biological Society of Washington 88 (1976): 469–488.

OTHER

Mansfield, Duncan. "Snail Darter is No Longer in Danger of Extinction." Appalachian Focus Environmental News December 11, 2000 [cited May 2002]. <http://www.appalachianfocus.org/_enviro1/00000011.htm>.