SANBI

Rationale

Redtail Barb (Enteromius gurneyi) is a small minnow that historically ranged across many river catchments from the uMtamvuna River to the Mhlatuze River in KwaZulu-Natal, South Africa (Skelton 2001, Scott et al. 2006). Uncertainty pertaining to the genetic diversity of the populations of Redtail Barb still exists (Machordom and Doadrio 2001), which is currently being evaluated as part of a review of the larger Enteromius anoplus complex. Redtail Barb subpopulations from the Mfule, Mhlathuze, uMvoti, Tongati, Mdloti, lower Umngeni and uMlazi Rivers have potentially been extirpated, further studies is required to confirm these losses. The species is threatened by surrounding land uses including eutrophication and water abstraction which act synergistically and is intensified during periods of drought. The species has a generation length of three years and in the last 10 years has experienced a reduction of just more than 30% in its distribution range which is which is inferred to equate to a 30% population reduction. The species is assessed as Vulnerable A2ace.

Distribution

The historical range of the species extended from the uMtamvuna River to the Mhlathuze River in KwaZulu-Natal (Scott et al. 2006). The current distribution is based on the research by Evans et al. (in preparation) and stretches from the uMtamvuna River northwards to the Mooi River in the upper reaches of the Thukela Catchment in KwaZulu Natal Province, South Africa.

Habitat View more ecological information

Population trend

Trend

In 2007 the species was listed as Least Concern with the predation of alien invasive species listed as a threat. Following recent fish community well-being research in KwaZulu-Natal (Evans et al. in prep), the current distribution of Redtail Barb has been found to be restricted to the upper Thukela Catchment (Mooi River), the upper uMngeni River Catchment and the upper Lovu and Mkomazi and the middle and lower Mzimkhulu and uMtamvuna rivers, however, further field surveys are required to confirm its currently distribtuions (Evans et al. in prep). Subpopulation from the Mfule, Mhlathuze, uMvoti, Tongati, Mdloti, lower Umngeni and uMlazi rivers have potentially been extirpated, however, further surveys are needed to confirm this status. Due to threats and associated impacts on larger rivers the species has become isolated by retreating into tributaries. It was previously common and while it still has a relatively large range (EOO = 5,819 km²), it has experienced a reduction in its population size across its distributional range estimated at 30% based on a reduction on available habitat.

Threats

The species is threatened by the synergistic effects of land use practices, alien fishes and increases in drought associated with climate change. Specific threats include agriculture, urban and peri-urban communities and associated stressors such as waste water treatment works and industries affecting water quality, quantity and habitat of the rivers and alien species. The recent synergistic effects of drought experienced in the region between 2015 and 2016, has resulted in many rivers drying up, which along with land use practices has contributed to the decline in the distribution of the species.

Conservation

Although many subpopulations occur within conservation areas of the provincial conservation agency Ezemvelo KwaZulu-Natal Wildlife, there are no efforts to protect Redtail Barb nor to reduce the threats to these subpopulations.

References

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 author = {Engelbrecht, J. S., & Bank, F. V. D. },
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 title = {Genetic relationships between marico barb (Barbus motebensis, Steindacher 1894), redtail barb (B. gurneyi, Günther 1868) and amatola barb (B. amatolicus, Skelton 1990). },
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,]

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