protected species found in the Olifants River; it is more The Clanwilliam yellowfish (Labeobarbus seeberi) is another large cyprinid in this basin endemic to the Western Cape region. It has been subject to some captive breeding effort and its stocks are in better shape. However, it may have gone extinct in the Olifants River, and at least is almost certainly gone from between Olifants Gorge and Clanwilliam Dam. Whether it will be reintroduced is unclear, as sawfin and Clanwilliam yellowfish adults are probably ecological competitors, and until the Olifants River is sufficiently restored ecologically both might not be able to thrive at the same time. The Olifants River marks the northern limit of the Cape galaxias (Galaxias zebratus), a South African fish species sharing the same habitat as imported trout species and living in an area between the Olifants and the Keurbooms River. Although in South Africa this relatively delicate fish is only Near Threatened, in Australia species of the same genus were driven to extinction by competing salmonids. Other species that occur in the Olifants riverine system include Twee River redfin, (Pseudobarbus erubescens), Fiery redfin (Pseudobarbus phlegethon), Austroglanis barnardi, Clanwilliam rock-catfish (Austroglanis gilli), Chubbyhead barb (Enteromius anoplus), and Clanwilliam sandfish (Labeo seeberi). The most severe biological threat to the river's ecosystem is probably the Smallmouth Bass (Micropterus dolomieu). Originally introduced for sport fishing, it has become something of a pest by depleting the stocks of other fish species. Its eradication is encouraged under the Cape Action for People and the Environment program. Non-biological threats are mainly excessive removal of river water for irrigation, and the resultant toxic surface runoff from plantations (especially agrumes). These are often grown right up to the river bank, without leaving sufficient natural vegetation to filter out pesticides and fertilizer and halt erosion, and thus causing both river and adjacent cropland to degrade. See also List of rivers of South Africa References External links Flyfishing Olifants River Military History Journal Vol 9 No 1 - June 1992 River Rafting Adventures / Cape Town - Cape Adventure Zone Invasion biology A preliminary assessment of the impact of alien rainbow trout (Oncorhynchus mykiss) on indigenous fishes of the upper Berg River, Western Cape Province, South Africa Rivers of the Western Cape