Conserving the fishes of the Twee River, Western Cape, South Africa: revisiting the issues

The Twee River catchment contains two endemic fish species - the Twee River redfin and the Twee River galaxias - which are threatened by water abstraction, habitat degradation, and the presence of introduced fishes. Fyke nets were used to determine the current distribution ranges of fish in the catchment to update a 1997 survey and to provide key information for the compilation of a conservation strategy for the Twee River redfin, Barbus erubescens. Population estimates from 1997 placed their total number at 8 400, but population size could not be estimated from the present surveys. A number of small populations of Twee River redfin and Twee River galaxias, which are restricted to two short stretches of tributary rivers, were identified. Their long-term survival remains uncertain. Conservation action, including the eradication of alien fish and the creation of a dedicated sanctuary for the endemic populations, is recommended.