Localized Effects of Coal Mine Drainage on Fish Assemblages in a Cumberland Plateau Stream in Tennessee

Abstract

ABSTRACT The upper watershed of North Chickamauga Creek (NCC), a fourth-order tributary to the Tennessee River, Tennessee, has been impacted by decades of acid mine drainage (AMD) from abandoned coal mines. We assessed fish assemblages, pH, conductivity, and sediment coverage at 12 study reaches (six AMD sites and six reference sites) in the Cumberland Plateau region of the NCC system, May-September 1998. Stream pH increased (3.6 to 6.0) and conductivity decreased (296 to 49 μS/cm) downstream of the AMD-impacted area; however, no discernable gradient was observed in sediment cover. Elevated conductivity at AMD-impacted sites reflected increased concentrations of dissolved metals and other inorganic ions. Reference sites exhibited higher pH (6.0–6.4) and lower conductivity (13–28 μS/cm). Acidified reaches were characterized by low fish species richness (r = 0.885, P = 0.0007) and abundance (r = 0.854, P = 0.0017); no fish were observed at sites where the mean pH was <5 Centrarchids (mostly bluegill [Lepomis macrochirus] and green sunfish [L. cyanellus]) comprised >90 % of the catch at AMD sites, whereas cyprinids (creek chub [Semotilus atromaculatus] and blacknose dace [Rhinichthys atratulus]) accounted for >90 % of the catch at reference sites. Findings from this study document the negative effects of acid drainage from coal mines on fish assemblages in a Cumberland Plateau stream.