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Rationale

Fiery Redfin (Pseudobarbus phlegethon) is a range restricted species, known from five tributaries (five locations) in the Olifants-Doring River System (ODRS), South Africa. Over the last 70 years the Jan Dissels subpopulation that forms part of the Olifants lineage has progressively declined to extinction. However, the major decline occurred during the initial establishment of alien invasive such as Bass species (Largemouth Bass (Micropterus salmoides), Smallmouth Bass (Micropterus dolomieu) and Spotted Bass (Micropterus punctulatus)) in the 1930s and 1940s. Fiery Redfin currently has an extent of occurrence (EOO) of 290 km² and area of occupancy (AOO) of 64 km² (based on a 2x2 km² grid overlay on the range map). There is continuous decline in its AOO, the number of mature individuals and habitat quality due to alien invasive fish and water abstraction. The species only occurs in one provincial Nature Reserve (Cederberg Nature Reserve Complex). The five subpopulations are severely fragmented (small and isolated) due to the introduction of alien fishes, however they will persist without the need for immigration, with the exception of the Oudste subpopulation, which accounts for less than half of the population. The species therefore qualifies for Endangered under criteria B1ab(ii,iii,iv,v)+2ab(ii,iii,iv,v).

Distribution

Fiery Redfin (Pseudobarbus phlegethon) was widespread before the introduction of Bass species (Micropterus spp.) into the Olifants-Doring River System (ODRS) in the 1940s (de Moor and Bruton 1988), when it would have occurred in the Olifants River itself (Harrison 1938, Barnard 1943) and tributaries such as the Jan Dissels River. It now occurs in the Oudste, Thee, Noordhoeks, Boskloof and Rondegat tributaries of the Olifants River system on the western side of the Cederberg Mountains (Bills 1999, Swartz 2000, Swartz 2004, Van der Walt 2014).

Habitat View more ecological information

Population trend

Trend

No detailed population information is currently available, however, the species is known from five subpopulations in the Oudste, Thee, Noordhoeks, Boskloof and Rondegat tributaries of the Olifants River system on the western side of the Cederberg Mountains (Bills 1999, Swartz 2000, Swartz 2004, Van der Walt 2014), where more than 50% of the subpopulations are small and severely fragmented.

Threats

Fiery Redfin has experienced a significant range contraction as a result of the introduction of alien invasive fish species. The most severe impact was probably in the 1930s and 1940s following the introduction of three Bass species (Largemouth Bass, Smallmouth Bass and Spotted Bass) into the ODRS (de Moor and Bruton 1988). This taxon went extinct in the Jan Dissels River several decades ago as a result of bass predation. The Jan Dissels River is a major tributary of the Olifants River and Fiery Redfin are no longer found in mainstream areas where they probably occurred before the introduction of invasive alien fishes. The subpopulation in the Rondegat River is protected from bass invasion by a waterfall, providing a natural barrier. Unsustainable water extraction during the dry season (October to March) is also a major threat, especially where the lower reaches of tributary streams are affected. The abstraction of the total summer flow by riparian farmers in the Oudste, Thee and Noordhoeks Rivers has had one benefit in that it has prevented alien Bass species from invading these rivers (Van der Walt 2014).

Uses and trade

Fiery Redfin is listed as an Endangered Wild Animal 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 sometimes kept in public aquaria for awareness purposes.

Conservation

The most important tributaries and mainstem areas for indigenous fish conservation in the Olifants River system have been identified as “Fish Sanctuary Areas” in the national Atlas of Freshwater Ecosystem Priority Areas (Nel et al. 2011). The provincial conservation authority, CapeNature, has initiated successful river rehabilitation projects using rotenone to eradicate alien fishes from priority fish conservation areas. The Rondegat River has been the recent successful focus of this programme, with a combined project to eradicate Smallmouth Bass from 4 km of the river (Weyl et al. 2014) as well as invasive vegetation from the riparian zone (Impson et al. 2013). Fiery Redfin and several other indigenous species are successfully re-colonising the area cleared of bass (Weyl et al. 2014). The local conservation agency, CapeNature, recently published a report on priority rivers in the ODRS for fish conservation to improve awareness and management of these rivers (Impson et al. 2016).

References

[@article{18475,
 author = {Skelton, P.H.},
 title = {A Complete Guide to the Freshwater Fishes of Southern Africa},
 year = {2001}
}
,@article{2426,
 author = {Bills, R.},
 title = {Biology and conservation status of the Clanwilliam rock catfish and spotted rock catfish},
 year = {1999}
}
,@book{2426,
 address = {Gland, Switzerland and Cambridge, UK},
 author = {Baillie, J. and Groombridge, B.},
 publisher = {International Union for Conservation of Nature},
 title = {1996 IUCN Red List of Threatened Animals},
 year = {1996}
}
,@article{2426,
 author = {IUCN},
 title = {IUCN Red List of Threatened Animals},
 year = {1990}
}
,@book{2426,
 address = {Gland, Switzerland and Cambridge, UK},
 author = {Groombridge, B.},
 publisher = {IUCN},
 title = {1994 IUCN Red List of Threatened Animals},
 year = {1994}
}
,@techreport{2426,
 author = {Impson, D., van der Walt, R. & S. Henning},
 institution = {CapeNature Internal report},
 title = {Rivers of importance to fish conservation in the Olifanst-Doring River System and associated management issues},
 year = {2016}
}
,@electronic{2426,
 address = {www.iucnredlist.org},
 author = {IUCN},
 title = {The IUCN Red List of Threatened Species. Version 2017-3},
 year = {2017}
}
,@book{2427,
 address = {Gland, Switzerland and Cambridge, UK},
 author = {IUCN Conservation Monitoring Centre},
 publisher = {IUCN},
 title = {1986 IUCN Red List of Threatened Animals},
 year = {1986}
}
,@article{2427,
 author = {Weyl, O. L. F., Finlayson, B., Impson, N. D., Woodford, D. J. and Steinkjer, J. },
 journal = {Fisheries},
 number = {6},
 pages = {270--279},
 title = {Threatened endemic fishes in South Africa’s Cape Floristic Region: A new beginning for the Rondegat River.},
 volume = {39},
 year = {2014}
}
,@techreport{2562,
 address = {Pretoria, South Africa},
 author = {De Moor, I.J. and Bruton, M.N.},
 institution = {Foundation for Research Development, Council for Sscientific and Industrial Research},
 title = {Atlas of alien and translocated indigenous aquatic animals in southern Africa},
 year = {1988}
}
,@phdthesis{2562,
 author = {Van der Walt},
 school = {Cape Peninsula University of Technology},
 title = {Black bass (Micropterus spp.) in the Olifants- Doorn River system: distribution, distribution barriers, predatory impact and management},
 year = {2014}
}
,@techreport{2569,
 author = {Nel, J.L., Driver, A., Strydom, W.F., Maherry, A., Petersen, C., Hill, L., Roux, D.J., Nienaber S., van Deventer, H., Swartz, E. and Smith-Adao, L.B. },
 title = {Atlas of freshwater ecosystem priority areas in South Africa.},
 year = {2011}
}
,@article{18477,
 author = {Swartz, E.R.},
 title = {Phylogeography, phylogenetics and evolution of the redfins (Teleostei, Cyprinidae, <i>Pseudobarbus</i>) in southern Africa.},
 year = {2005}
}
,@article{107649522,
 author = {Swartz, E.R., Flemming, A.F. and Mouton, P. le F.N.},
 title = {Contrasting genetic patterns and population histories in three threatened redfin species (Cyprinidae) from the Olifants River System, western South Africa},
 year = {2004}
}
,@article{107649522,
 author = {Swartz, E.R.},
 title = {Population genetics of <i>Pseudobarbus phlegethon, Barbus calidus</i> and <i>B. erubescens</i> (Teleostei: Cyprinidae) of the Olifants River System, Western Cape.},
 year = {2000}
}
,]

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