Effects of Antimycin and its Neutralizing Agent, Potassium Permanganate, on Aquatic Macroinvertebrates in a Great Smoky Mountains National Park Watershed

We assessed the effects of antimycin (Fintrol) on benthic macroinvertebrates during a large Brook Trout Salvelinus fontinalis restoration project in the southeastern United States. Control and treatment sites were established in first-through fourth-order streams throughout the watershed and below the fish passage barrier where a neutralizing agent (potassium permanganate [KMnO4]) was administered. Hess samples were collected before and after chemical application (short term: 1 and 2 months after; long term: 9 and 12 months after). Analysis of similarity, nonmetric multidimensional scaling, and repeated-measures ANOVA were used to determine differences in assemblage metrics among control, treatment, and neutralization sites over time. Macroinvertebrate communities and their responses to antimycin were different at downstream (third- and fourth-order) sites relative to headwater (first- and second-order) sites. Overall, abundances (especially stonefly and caddisfly abundances) increased after antimycin application, reflecting a positive response within the macroinvertebrate assemblage. Several variables, including mayfly and stonefly abundances, were significantly different among control, concentrated-KMnO4, and dilute-KMnO4 sites; however, differences were undetectable after 9 months. Many taxa were substantially more abundant several months after treatment, indicating a thriving macroinvertebrate assemblage throughout the watershed. Future studies yielding similar results would suggest that native fish stocking efforts can commence shortly after chemical degradation.