David Etnier joined the UT faculty in 1965 and received the PhD in zoology from the University of Minnesota in 1966. He retired in 2001, become professor emeritus, and continued teaching and research. Over his career he amassed for the university a collection of over three hundred specimens of fishes—a collection that at his retirement was one of the top 20 in the nation.
He helped to discover over 410 species of aquatic insects, three of which bear his name. His most famous discovery was in 1973 of the snail darter (Percina tanasi) in waters just above the site of TVA’s proposed Tellico Dam. This darter was added to the endangered species list, created by the Endangered Species Act, and stopped construction of the Tellico Dam while the courts decided whether provisions of the Endangered Species Act would permanently stop the dam’s construction. Appellate courts ruled in favor of the snail darter, but US Senator Howard Baker Jr. pushed through congress an exception to the Endangered Species Act, which allowed completion of the dam.
In 1993, from research conducted over 25 years, Etnier published The Fishes of Tennessee with coauthor Dr. Wayne C. Starnes, a former student. The text provides both a taxonomic source and a natural history reference. In 2004 he received the first Bill Russell River Hero Award from the Tennessee Clean Water Network.
Scientists have honored Etnier by naming seven species for him. Included are three caddis flies (Ceratopsyche etnieri, Lepidostoma etnieri, and Neophylax etnieri); a darter (Etheostoma etnieri); a beetle (Laccornis etnieri); a crayfish (Orconectes etnieri); and a tapeworm (Callintinella etnieri).