Dams and fish conservation in Kruger Park

Role of dams for the conservation of fishes in Mpumalanga and Kruger National Park focus IUCN listed spp. Brevis/E. Rapax and O. Mossambicus

The presence of large dams can break the connectivity of water flow in rivers and pose difficulty for migratory fish to move upstream or downstream. Dams are known to impose very specialised and rigorous conditions on fisheries and aquatic environments. However, a well-designed dam can bring lots of benefits to fish communities by maintaining fish stock, reduce the risk of overexploitation and prevent the loss of fish biodiversity.

The endangered Orange-fringed River Bream (Chetia brevis) is known to have been translocated into 4 unknown dams of the Kruger National Park in 1975. This species thrives in habitats such as deep pools (> 1 m) with sandy substrates and dense riparian vegetation. The main threats to this species include Agriculture, dam and water modifications, pollution and invasive species. The Silverfish (Enteromius rapax) is known to be located in deep pool or dams within the middle and upper reaches of Kruger National Park. Major threats such as dam and water modifications, pollutions, climate change and invasive species have led to the silverfish populations nearing extinction within the Kruger National Park. The Mozambique tilapia (Oreocromis mossambicus) is a vulnerable fish species that thrives in standing waters across Mpumalanga and Kruger National Park and are highly threatened by the Nile tilapia (Oreochromis niloticus) through hybridisation.

The aim of this study is to evaluate the locations, abundance and frequency of occurrence of these different fish species within dams of the Kruger National Park.

Client and or collaborating stakeholders:University of Mpumalanga (UMP), Kruger National Park (SANPARKS), USA Resilience’s Water Program.

Interesting and important outcomes or prospects: Despite the disadvantages of dams, with proper management, dams can be of help to conserve and built up population numbers of these fish species that need deep pools to survive. Dam management and monitoring of fish populations will contribute to the conservation of these and many more freshwater fish species.