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Rationale (Changed due to Taxonomy)

This species as currently described has three discrete and geographically widely spaced populations that can be broadly divided into southern (the uMkhomazi, uMgeni, Tugela and the Inkomati river systems in South Africa), central (the Buzi and Pungwe river systems) and northern (Ruo River in Malawi) populations. An ongoing study has revealed that these three populations represent at least four distinct lineages. Non-native species, particularly trout, have been introduced into the cool mountain tributaries where these fishes occur, but their actual impact require investigation. Native vegetation in the upper catchments of a number of the streams has also been replaced with monoculture plantations, while agricultural activities (particularly in the Buzi, Pungwe and Ruo catchments) have caused habitat degradation through increased sedimentation and water turbidity. Populations within the Eastern Highlands of Zimbabwe (Pungwe and Buzi catchements) are further threatened by gold panning activities which have degraded instream habitats through increased turbidity and deposition of fine sediments which reduces habitat complexity. This species has many localized threats, however because of its large distribution, with an estimated extent of occurrence (EOO) of 485,198 km²and a estimated area of occupancy (AOO) of 756 km² it does not trigger any of the threat categories. The species is classified as Least Concern, however there is urgent need to resolve its taxonomy, as many smaller populations may represent restricted species.

Distribution

Natal Mountain Catfish (Amphilius natalensis), as currently described, has three discrete and geographically widely spaced populations that can be broadly divided into southern (the uMkhomazi, uMgeni, Tugela and the Inkomati river systems in South Africa), central (the Buzi and Pungwe River Systems) and northern (Ruo River in Malawi) populations (Skelton 1984, 2001). Results from an ongoing taxonomic revision of this species however indicate that the southern population is genetically distinct from the central and northern populations, with the latter two populations potentially representing at least three undescribed species. An ongoing study will determine the taxonomic integrity and will revise the distribution ranges of the taxonomic entities within this complex.

Habitat View more ecological information

Population trend

Trend

Breeding in the Natal Mountain Catfish occurs in summer when changes in water chemistry or increased flow rate following the onset of the rain season are thought to be the cues that trigger spawning (Marriot et al. 1997). To date, no dedicated studies have been conducted to determine the population size of this species. The biology and population dynamics of this species will need to be reviewed in light of the discovery of hidden diversity within this complex.

Threats

The key threats include smothering of habitat from agricultural and gold panning activities as well as water abstraction. The replacement of native forests and with non-native monoculture plantations (mainly Pines (Pinus species) and Gumtrees (Eucalyptus species) are potential stressors to the environment as they may alter stream flow and timber harvesting may lead to smothering of habitats through increased sediment input. However, these are inferred threats whose actual impact needs to be evaluated. Alien fishes, particularly Rainbow Trout (Oncorhynchus mykiss) and Brown Trout (Salmo trutta) have also been widely introduced in several mountain streams across the species’ distribution range, but their actual impacts need to be evaluated .

Conservation

More research is required for this species. Conservation of streams where A. natalensis occurs, including control of water abstraction, sustainable agricultural and forestry activities and management of non-native species, is needed.

References

[@article{18475,
 author = {Skelton, P.H.},
 title = {A Complete Guide to the Freshwater Fishes of Southern Africa},
 year = {2001}
}
,@article{182382,
 author = {Skelton, P.H.},
 journal = {Annals of the Cape Provincial Museums. Natural History},
 number = {3},
 pages = {41--71},
 title = {A systematic revision of the species of the catfish genus <i>Amphilius</i> (Siluroidei, Amphiliidae) from east and southern Africa},
 volume = {16.0},
 year = {1984}
}
,@article{182382,
 author = {Marriott, M.S., Booth, A.J. and Skelton, P.H.},
 journal = {Environmental Biology of Fishes},
 pages = {461--470},
 title = {Reproductive and feeding biology of the Natal mountain catfish <i>Amphilius natalensis</i> (Siluroidei: Amphiliidae)},
 volume = {49.0},
 year = {1997}
}
,@electronic{182382,
 address = {http://researcharchive.calacademy.org/research/ichthyology/catelog/fishcatmain.asp},
 author = {Eschmeyer, W.N., Fricke, R. and Van der Laan, R. (eds.)},
 title = {Catalog of Fishes: genera, species, references. Updated 29 March 2018},
 year = {2018}
}
,]

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Red List of South African Species