Habitat selection of the channel darter, Percina (Cottogaster) copelandi, a surrogate for the imperiled pearl darter, Percina aurora

Percina (Cottogaster) aurora is an imperiled species under consideration for listing by the U.S. Fish and Wildlife Service. To better understand habitat use of P. aurora, we studied a related and more abundant Cottogasterspecies, Percina copelandi, from the Ouachita River, Arkansas. We used a laboratory stream system to examine mesohabitat selection (pools versus riffles) and microhabitat selection (substratum particle size) of P. copelandi over three temperature regimes (summer, spring, and winter). Percina copelandi selected pool habitats over riffles and selected pools with coarse substrata (e.g., cobble) over fine substrata (e.g., gravel). In riffles, P. copelandi selected large substrata during winter and spring but did not show particle size selection during summer. These data, and various published and unpublished field data for P. aurora, suggest that habitat use of P. aurora is also centered around deep runs and pools, with large substrata likely being more important at low water temperatures.