Population Status and Nesting Biology of the Rare Barrens Darter, Etheostoma forbesi

Abstract

Abstract The Barrens darter Etheostoma (Catonotus) forbesi (Teleostei: Percidae) is a rare stream fish endemic to the upper Caney Fork River system in the Barrens Plateau region of middle Tennessee. We studied the darter's population characteristics and selected aspects of its nesting biology at 10 sites surveyed during April 2004. In our survey, we caught a total of 75 Barrens darters at a rate of 21 individuals per hour of backpack-electrofishing effort. At least one male Barrens darter was present at six of the 10 sites. Females outnumbered males by a ratio of 1.4 to 1. Total lengths ranged 44–97 mm, averaging 62 mm for females and 78 mm for males. The number of Barrens darters seen in the present survey was similar to a 1994 survey. However, both surveys reveal a species in need of conservation, with low abundance at most known sites within its limited geographic range. We found 20 Barrens darter nests located on the flat undersides of cobbles with a mean length, width and thickness of 17 × 13 × 5 cm....