Short-term Response of Fish Assemblage to a Low-head Dam Removal

Abstract

Over the last two decades, over 1,200 dams have been removed in the United States due to concerns about safety and ecological integrity. We wanted to investigate the possible changes in fish community structure following the removal of a low-head dam on Roaring River in north-central Tennessee. We hypothesized that there would be significant differences in species assemblage in perennial upstream riffles and newly established downstream riffles and that tolerant, more mobile species would be the first fishes to colonize downstream riffles. Fish assemblages were assessed using backpack electrofishing units at six sample sites at and above the site of the removed dam. There were significant differences between communities in riffle habitats vs communities in pool habitats across all sites. Since few studies have been done to explore the effects of dam removal on ecosystem recovery processes, our study will contribute to our expanding knowledge of the ecological effects of dam removal.