Abstract
M.Sc.
This study aims to assess the potential impacts of coal mine activity on exposed fish assemblages in the Mpumalanga Highveld area. A control-impact-assessment method was applied, with sites located upstream and downstream from mining activity. All sites were located in the upper Olifants catchment. Field assessments were done over a high flow and low flow period. It was ascertained that water quality variables contributing towards differences between upstream and downstream environmental conditions are salt concentrations, pH and oxygen saturation. Alterations on fish community structures indicated a categorical decline in abundances and species richness at sites situated downstream from mining activity, while Fish Response Assessment Index (FRAI) scores similarly reflected more impaired fish assemblages at downstream sites. Redundancy analysis (RDA), using fish assemblages and FRAI driver metrics explained 36.5 % of variance obtained and reflected particular alteration in Barbus neefi, B. paludinosus, Tilapia sparrmanii and Pseudocrenilabrus philander populations. Sites most severely impacted were identified, as well as the main drivers responsible for changes in fish assemblages. The Cover metric contributed significantly (p<0.05 to variance measured. Subsequent community threshold management targets are presented for problem sites, which aim to manage each site at an ecological category one class higher than the Present Ecological State (PES).