I currently hold a DSI/NRF South African Research Chair in Inland Fisheries and Freshwater Ecology. My research contributes towards better understanding impacts on freshwater fish communities and includes aspects of conservation, fisheries and invasion biology. My approach is multidisciplinary and focuses not only on describing natural systems and processes but also incorporates research on understanding how humans alter and benefit from aquatic systems. Recent work includes assessments of the distribution and impacts of alien fishes in aquatic ecosystems ranging from headwater streams in the Eastern Cape to large Rift Valley and estuarine Lakes in Southern Africa; biological investigations on fishes in both invaded and natural environments; assessments of fisheries based on indigenous and alien fishes and, more recently the role that alien fishes play in subsistence and recreational fisheries in Southern Africa.