The Tennessee River is one of the most aquatically biodiverse river systems in North America. It is also habitat for the largest nesting population of Bald Eagles in the United States.

The Nature Conservancy considers the Tennessee Basin as a whole to be the single most biologically diverse river system for aquatic organisms in the United States. It also harbors the highest number of imperiled species of any large basin in North America with 57 fish species and 47 mussel species considered to be “at-risk.” The southeastern U.S. possesses about 90% of the world’s species of mussels and crayfish, about 73% of the aquatic snails, and about 50% of the freshwater fish of the continental United States. The Tennessee River system alone is home to about 230 species of fish and 100 species of mussels, many of which are endemic to the watershed. The Tennessee River is currently the most important source of commercial mussels in the world.

Snail Darter
The snail darter (Percina tanasi) is a small fish native to the waters of East Tennessee. The fish was declared an endangered species in 1975. On July 5, 1984, the snail darter's status was lowered to threatened.

Endangered and Threatened

However, about a dozen fish species are federally listed as endangered or threatened and about 65 other species are listed under management categories used by the states. About 30 mussels have been extirpated from the Tennessee River system, of which about a third are considered to be globally extinct. Twenty-eight mussels are under federal protection, and 56 mussels are listed by the states in the watershed. The Tennessee River system also claims two crustaceans and four snails under federal protection. The Tennessee River Basin contains many endangered species. There are endangered fish species, including the Alabama cavefish (Speoplatyihimus poulsoni), Palezone shiner (Notropis albizonatus), Snail darter (Percina tanasi), and the Spotfin chub (Cyprinella monacha). Endangered mussel species include Oyster mussel (Epioblasma capsaeformis), Cumberland monkeyface (Quadrula intermedia), and Dromedary pearlymussel (Dromus dromas). There is also one endangered snail species, Anthony’s Riversnail (Athearnia anthonyi). There are four endangered flowers: Green Pitcher Plant, Harperella, Morefield’s Leather Flower, and Mountain Skullcap. There are two endangered terrestrial species: Red-cockaded Woodpecker and the Gray / Indiana Bat. The largest populations of nesting Bald Eagle and Gray Bat are in the Tennessee River Basin.

Hellbender Salamander
The hellbender salamander is also found in the Tennessee River watershed. (Cryptobranchus alleganiensis) is a giant salamander, native to North America, which inhabits large, swiftly flowing streams with rocky bottoms. The population of hellbenders have declined dramatically due to poor water quality, human encroachment and dams.