SANBI

Rationale (Changed due to New Information)

This species was previously declared regionally extinct in South Africa after several surveys in the past failed to find any specimens of the Maloti Minnow (Pseudobarbus quathlambae) from the type locality in the uMkhomazana River or elsewhere in South Africa (Crass 1960, 1964; Jubb 1966, Pike and Karssing 1995). The species was rediscovered during recent surveys of the Mzimkhulu River System in KwaZulu Natal, South Africa (Kubheka et al. 2017). The Senqunyane populations in the Lesotho Highlands is also thought to have been extirpated (Shelton et al. 2017). This species is now known from six subpopulations, five in Lesotho and the recently discovered population in KwaZulu Natal. Decline in population size for some of these subpopulations is ongoing due to invasion by alien fishes in the Lesotho Highlands (Shelton et al. 2017). The remnant subpopulations constitute five locations, (i) the Maremoholo has barriers that prevent upstream invasion of non-native fishes, (ii) the Sani and Matsoku constitute one location as there are no barriers between them and non-native fishes can move freely between the two tributaries, (iii) the Jorodane and Bokong also constitute one location, but these subpopulations are now represented by only few individuals of P. quathlambae due to the presence of Smallmouth yellowfish (Labeobarbus aeneus) and Orange River Mudfish (Labeo capensis) that have expanded their ranges through the inter basin transfer scheme, (iv) the introduced Upper Tsoelikane population is still thriving, and (v) the recently discovered uMzimkhulu population. The area of occupancy (AOO) is estimated as 128 km² based on distribution records from the Lesotho Highlands as well a recent records for the recently discovered population in South Africa. It has been extirpated from the uMkhomazana River where it was historically abundant (Pike & Tedder 1973), and ongoing decline for some of the populations is likely due to the presence of invasive alien species (Shelton et al. 2017). The species qualifies as Endangered under criteria B1ab(ii,iii,v). It should be noted that Pseudobarbus quathlambae potentially represents at least two distinct taxonomic entities which are severely threatened due to narrow distribution ranges, but this will be confirmed through ongoing detailed taxonomic evaluation of this species.

Distribution

This species was previously thought to had gone extinct in South Africa, but recent surveys led to the rediscovery of an extant population in two small streams in the Mzimkhulu River system (Kubheka et al. 2017). From a conservation point of view, the precise localities must remain undisclosed, because of the restricted geographic range of the known populations, until suitable conservation measures for this species have been put in place. Extant populations of this species also occur in seven tributaries of the Upper Orange River system, the Sani, Matsoku, Tsoelikane, Senqu, Maremoholo, Jorodane and Bokong rivers in the Lesotho Highlands (Skelton et al. 2001).

Habitat View more ecological information

Population trend

Trend

The Mohale lineage has suffered severe decline in population size compared to historical records due to impacts of non-native fish species (Shelton et al. 2017). The species is also likely to have been extirpated from some of localities where is was historically recorded in the Lesotho Highlands (Shelton et al. 2017). The status of the other populations in the Lesotho Highlands is uncertain as there have been no recent surveys done in these tributaries. As the KwaZulu Natal population (uMzimkhulu) has only been recently rediscovered after the species had been declared regionally extinct in South Africa for almost eight decades, no information is available on population trends for the uMzimkhulu population. Further surveys are however required to assess the current status and population dynamics of this recently discovered population.

Threats

The major threat is alien invasive fish species, particularly Rainbow Trout (Oncorhynchus mykiss) and Brown Trout (Salmo trutta) that have been widely introduced in streams across the native range of the species, both in the Lesotho Highlands and KwaZulu Natal. The water development schemes in the Lesotho Highlands also poses a severe threat as the inter basin transfer canals will lead to further spread of non-native and extralimital species such as Labeobarbus aeneus and Labeo capensis (Shelton et al., 2017). A potential threat is habitat degradation due to the construction of the Mohale Reservoir which caused an increase in human density and expansion of agricultural activities. This could lead to impacts such as sedimentation, pollution and water abstraction. Further research is needed to confirm the impacts of these potential threats as recorded in the Mohale populations (Shelton et al. 2017).

Conservation

No specific conservation actions are planned for this species. Immediate conservation measures are needed to secure the remnant populations from being invaded by non-native and extralimital species. Urgent action is required in the Lesotho Highlands where populations have been extirpated in recent years. In South Africa, this species does not occur in any protected area. Urgent taxonomic research is required to assist in conservation efforts, as this species may constitute two distinct species.

References

[@article{18475,
 author = {Skelton, P.H.},
 title = {A Complete Guide to the Freshwater Fishes of Southern Africa},
 year = {2001}
}
,@article{18475,
 author = {Pike, T. and Karssing, R.J.},
 title = {Investigation of the presence of Maluti Minnows, <i>Pseudobarbus quathlambae</i> in the Umkomozana River.},
 year = {1995}
}
,@book{18475,
 address = {Pietermaritzburg},
 author = {Crass, R.S.},
 publisher = {Shuter and Shooter},
 title = {Freshwater Fishes of Natal},
 year = {1964}
}
,@article{18475,
 author = {Barnard K.H.},
 journal = { Annals of the Natal Museum},
 pages = {525--528},
 title = {Description of a new species of fresh water fish from Natal.},
 volume = {8.0},
 year = {1938}
}
,@article{18475,
 author = {Crass RS},
 journal = {Annals of Natal Museum},
 pages = {405--458},
 title = {Notes on the freshwater fishes of Natal with descriptions of four new species.},
 volume = {14.0},
 year = {1960}
}
,@article{18475,
 author = {Jubb RA.},
 journal = {Piscator},
 pages = {78--80},
 title = {Labeo quathlambae, a rare freshwater fish now feared extinct},
 volume = {67.0},
 year = {1966}
}
,@article{18475,
 author = {Kubheka PS, Chakona A, Mazungula DN},
 journal = {African journal of Aquatic Science},
 pages = {303--306},
 title = {The Maloti minnow Pseudobarbus quathlambae (Barnard, 1938) is not extinct in South Africa.},
 volume = {42.0},
 year = {2017}
}
,@article{18475,
 author = {Pike, T and Karsing, R.J.},
 journal = {Lammergeyer},
 pages = {9--15},
 title = {Rediscovery of Oreodaimon quathlambae (Barnard).},
 volume = {19.0},
 year = {1973}
}
,]

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