|Scientific Name:||Pseudobarbus capensis Smith, 1841|
Barbus andrewi Barnard, 1937
Pseudobarbus andrewi Barnard, 1937
|Taxonomic Source(s):||Yang, L., Sado, T., Hirt, M.V., Pasco-Viel, E., Arunachalam, N., Li, J., Wang, X., Freyhof, J., Saitoh, K., Simons, A.M., Miya, M., He, S. and Mayden, R.L. 2015. Phylogeny and polyploidy: Resolving the classification of cyprinine fishes (Teleostei: Cypriniformes). Molecular Phylogenetics and Evolution 85: 97-116.|
It must be noted that P. capensis formerly belonged to the genus Barbus, but following the work of Yang et al. (2015), Pseudobarbus was expanded to include additional species resulting in the renaming of the Breede-Berg River whitefish to ‘Pseudobarbus’ capensis (Skelton 2016). These nomenclatural changes were made because the type specimen on which the name Barbus capensis was based was re-identified as the Cape Whitefish or Witvis, and not the Clanwilliam Yellowfish, as previously thought (Skelton 2016). The name ‘Pseudobarbus’ capensis (Smith, 1841) for the Berg-Breede whitefish is in tune with the generic alignment of Yang et al. (2015).
|Red List Category & Criteria:||Endangered B1ab(iii,iv,v)+2ab(iii,iv,v) ver 3.1|
|Assessor(s):||Impson, D., Jordaan, M. & Van der Walt, R.|
|Reviewer(s):||Raimondo, D., Raghavan, R. & Freyhof, J.|
|Facilitator/Compiler(s):||Van Der Colff, D.|
The Berg-Breede River Whitefish (Pseudobarbus capensis, previously Barbus andrewi) was historically widespread in the Berg and Breede River systems of the Western Cape Province of South Africa. As a result of the impacts of alien invasive fishes and habitat degradation, most occurring in the mid 20th century, it is now confined to three to five threat defined locations in the Breede River System. These are the Brandvlei/Kwaggaskloof Dam which has the biggest subpopulations, the Sanddrif Dam and the middle reaches of the Breede River. It also occurs in the Hex River and Koekedou River but these two locations are considered nonviable subpopulations and most likely to go extinct in the near future. The extent of occurrence (EOO) has been calculated as 4699 km2 and the area of occupancy (AOO) is 60 km2. All subpopulations are currently experiencing continuous decline due to impacts by predatory alien fish species, which requires ongoing monitoring. The species is listed as Endangered B1ab(iii,iv,v)+2ab(iii,iv,v).
|Previously published Red List assessments:|
The Berg-Breede River Whitefish is endemic to the Berg and Breede River Systems of the Western Cape Province, South Africa (Skelton 2001). Originally widespread in both systems (Harrison 1952), it is now common only in two large impoundments (Brandvlei Dam near the town of Worcester and Sanddrif Dam near the town of De Doorns). It is believed to have gone extinct in the Berg River (Impson 2003). Recent surveys indicated that there is a viable subpopulation in the middle Breede River near the Brandvlei Dam, it also occurs in a small section of the Hex River and the Koekedoe River.
Native:South Africa (Western Cape)
|Range Map:||Click here to open the map viewer and explore range.|
Pseudobarbus capensis was originally abundant in both the Berg and Breede river systems (Harrison 1952). Prior to the 1950s it was considered a pest species by the Cape Department of Inland Fisheries because it competed with alien invasive trout species (Oncorhynchus mykiss and Salmo trutta) for food resources (Harrison 1953). The introduction of Smallmouth Bass (Micropterus dolomieu) between 1938 and 1940 into both systems led to major declines of P. capensis (De Moor and Bruton 1988). CapeNature, the provincial conservation agency for the Western Cape Province, considered the species extinct in the Berg System by 2000 (Impson 2003). The Breede River System has very low numbers of Berg-Breede River Whitefish in lotic environments, due to Smallmouth Bass (Micropterus dolomieu) invasion and habitat degradation. The Hex River, a major tributary of the Breede River, had a good recruiting population five years ago, however a severe flood caused habitat damage and it has recently been invaded by alien fishes above instream barriers. Since this invasion M. dolomieu and African Sharptooth Catfish (Clarias gariepinus) have caused a major decline in this subpopulation (Shelton et al. 2017).
A recent fish survey of Brandvlei Dam, a large public impoundment in the Breede River catchment near the town of Worcester, reported large numbers of juvenile and adult P. capensis (Dredge and Weyl 2015). The Sanddrif Dam, also in the upper Breede catchment, probably has a substantial P. capensis subpopulation, but much smaller than Brandvlei Dam. Several additional impoundments, mostly privately owned, have been stocked with the species in both river systems. Follow up visits to some of these impoundments in the last five years revealed that in many cases the fish were unable to establish, presumably due to a lack of spawning habitat for this species. A comprehensive fish survey of the main stream Breede River and large tributaries is proposed for late 2016 which will yield valuable information on the status of the P. capensis population in this system.
There are thus two recruiting subpopulations in lentic habitats (Brandvlei and Sanddrif dams) and a subpopulation of unknown status in the middle reaches of the Breede River. The small Hex River subpopulation has decreased to less than 20 adult fish as a result of alien fish invasion and is no longer considered viable. P. capensis was recently recorded by the South Africa Institute of Aquatic Biodiversity in the small Koekedou River near Ceres, but it is unlikely that this is a viable subpopulation.
|Current Population Trend:||Decreasing|
|Habitat and Ecology:|
The habitat requirements of Berg-Breede River Whitefish is not well understood. What is known is that it prefers larger rivers and does well in impoundments (Impson 2001). Adults prefer deep pools of larger rivers, where rock or overhanging vegetation cover is present, whereas juveniles are common in riffles (Impson 2007). Adults are omnivorous, feeding on bottom dwelling invertebrates and algae. Juveniles feed on zooplankton and small aquatic invertebrates (Skelton 2001). Berg-Breede River Whitefish breed in late spring, when water temperatures exceed 20 °C and schools of adults migrate to deep (1 to 1.5 m) riffles and spawn (Impson 2007). Fecundity is high with a 2.5 kg captive female yielding about 100,000 eggs (Smith 1987). The species spawns successfully in impoundments, with spawning occurring over gravel and rocky beds in shallow water (Impson 2001). A genetic study based on mitochondrial DNA indicated little variation between Berg-Breede River Whitefish subpopulations from the Berg and Breede River systems (Impson and Bloomer 1998). Berg-Breede River Whitefish used to co-occur with redfins (Pseudobarbus spp.), Cape Kurper (Sandelia capensis) and Cape Galaxias (Galaxias zebratus) before predatory alien fishes dominated mainstream and large tributary habitats. Further research is still needed to inform its biology.
|Continuing decline in area, extent and/or quality of habitat:||Yes|
|Use and Trade:||
Berg-Breede River Whitefish is listed as endangered under Schedule 1 of the Provincial Nature Conservation Ordinance for the Western Cape, thereby preventing the collection and trade of the species without a permit. It is also listed nationally as a Threatened or Protected Species under South Africa’s National Environmental Management: Biodiversity Act of 2004. It is an angling target in Brandvlei Dam where fish are common and appreciated by anglers. Translocations of this species are controlled by CapeNature’s Indigenous Fish Utilisation Policy (Jordaan et al. 2016). It is sometimes kept in public aquaria for awareness and education purposes.
Major threats are invasive alien fishes and habitat degradation due to agricultural activities. Predatory impacts of Smallmouth Bass (Micropterus dolomieu) being the most significant factor driving this species to extinction in the Berg River system. Bass species (Micropterus spp) dominate preferred Berg-Breede River Whitefish habitat and severely impact on recruitment as they eat all Berg-Breede River Whitefish juveniles. The Berg and Breede catchments are characterized by intensive agricultural development, with several large towns (Paarl, Robertson and Worcester) on major rivers, culminating in over-abstracted and polluted rivers that have become a haven for other alien fish species such as European Carp (Cyprinus carpio), African Sharptooth Catfish (Clarias gariepinus) and Mozambique Tilapia (Oreochromis mossambicus). These alien species compete with P. capensis for resources and African Sharptooth Catfish may exert substantial predation pressure on juvenile Berg-Breede River Whitefish.
The species is afforded some protection by being included as an endangered and protected species under both provincial and national environmental legislation which requires catch and release. Unfortunately less than 1% of its preferred habitat is inside formally protected areas. Pseudobarbus capensis has been successfully cultured (Smith 1987, Bok and Immelman 1989) for re-stocking purposes and to stock suitable impoundments. It has however not been cultured since 1995 as fish from the abundant Brandvlei Dam population were used for stocking purposes. Individuals from the Brandvlei Dam were stocked into the newly constructed Berg River Dam in 2007, but this action has had limited success (Impson 2011). Although not a true yellowfish (Labeobarbus), Berg-Breede River Whitefish has benefited from awareness and education initiatives (such as status reports) from the National Yellowfish Working Group. More recently, the Berg River Improvement Plan was initiated in 2012 by the Department of Environmental Affairs and Development Planning of the Western Cape Provincial government to rehabilitate the Berg River (BRS 2014). Part of the Plan is a whitefish reintroduction plan which was developed by CapeNature in 2016 using the guidelines of the IUCN. This involves the proposed reintroduction of Berg-Breede River Whitefish at two sites on the Berg River and into the Wemmershoek Dam, a large public impoundment within the natural distribution range of the species. It is envisaged that this conservation initiative by CapeNature will lead to the re-establishment of the species in the Berg River System and possible down-listing of the species by the next assessment.
|Citation:||Impson, D., Jordaan, M. & Van der Walt, R. 2017. Pseudobarbus capensis. The IUCN Red List of Threatened Species 2017: e.T2560A100114381.Downloaded on 23 April 2018.|
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