Saving the Clanwilliam yellowfish

In the rivers of the Western Cape, non-native fish were introduced for sporting purposes. The introduction of these ‘alien’ fish enhanced the region’s fishing experience for anglers, but has also led to many endemic fish species becoming endangered as they are preyed upon by the introduced varieties. Aurecon has worked with a number of inspiring organisations that have partnered to help rectify the damage that has been done in these rivers.

The Cape Critical Rivers Project is a ground-breaking initiative that aims to bridge areas of biodiversity conservation and water resource management in the Olifants-Doring catchment. Supported by the Save Our Species Foundation, the Endangered Wildlife Trust is working with project partners CapeNature; the Northern Cape Department of Environment and Nature Conservation; and the Freshwater Research Centre; towards protecting threatened freshwater ecosystems and species in this critical catchment.

"The Cape Critical Rivers Project will work to correct a mistake that was made many years ago — introducing alien fish into the rivers for sporting purposes." Louise Dobinson, Hydrology Specialist at Aurecon

Aurecon worked closely with the Endangered Wildlife Trust and the Freshwater Research Centre, providing specialist input to ensure that river flows in the Western Cape meet the ecological requirements of our endangered freshwater fish species.

The Cape Critical Rivers Project team collected hydrological flow data for four critical rivers in order to compare flows with the Ecological Reserve requirements and worked with Aurecon specialists to create a user-friendly monitoring tool for managing river flows. The goal of this innovative tool is to implement environmental flows through a simple methodology that can be done by the water users themselves, and secondly through a method that does not require enforcement but rather is done voluntarily by water users for their own benefit and to the benefit of the environment.

“Many of the fish in these rivers are vulnerable or critically endangered. Today the local fish are deemed to be good sporting fish, but it’s almost too late because the bass and blue gill sunfish have driven a lot of these species to extinction.”

Aurecon’s monitoring tool measures the flow of water in critical rivers around the Western Cape innovatively, simply and cost-effectively. It predicts the flows needed to maintain fish populations — giving a visual representation of the current water flows and comparing these to what is required by the native species. It also helps farmers to manage their water resources.

The project won the 2015 Mail & Guardian Biodiversity Stewardship Award.

This video is shared with the kind permission of explore4knowledge