SANBI

Rationale (Changed due to New Information|Incorrect data used previously)

Silver Labeo (Labeo ruddi) historically occurred in large schools but is now not recorded in surveys. The species has only been reported in South Africa once in the last 10 years from the Levubu River, Kruger National Park (KNP). Further, there have been no records in the Incomati River System in the last 20 years despite regular surveys within the KNP. It has been reported to prefer seasonal rivers, e.g. Shingwedzi River in KNP, but these are not regularly surveyed within the KNP and Limpopo Province and this region has experienced a prolonged drought, hence there is a high level of uncertainty regarding the specie’s persistence in these areas. It has, however, been recorded in the Bubi River near Bubi Dam, Zimbabwe where it was fairly common in 2014. It is expected to occur in the lowlands of Mozambique, but this area has not been recently surveyed. The absence of the species in rivers where it used to occur and the uncertainty in the Limpopo and KNP area are concerning. The taxonomic status of the Cunene population needs urgent examination as its may represent a distinct species. There is urgent need for surveys to be conducted for this species as its persistence in many systems are uncertain. The species is assessed as Data Deficient.

Distribution

Historical range included low-veld sections of the Limpopo and Incomati Rivers (South Africa, Swaziland and Mozambique, Zimbabwe). A single record from the lower Mbuluzi River in Swaziland. A northern population is known from the Cunene River on the Angolan-Namibian border, however taxonomic examination is needed for this population, as it may represent a separate species.

Habitat View more ecological information

Population trend

Trend

Very little information is available for this species. It was fairly common in the Bubi River (Limpopo River System), Zimbabwe in 2014 (Luus-Powell, 2014, pers. comm.). Only a single report from the Levubu River, KNP, in the last 10 years (2014). No reports from the Incomati River System in the Kruger National Park since the 1990s, or from the Olifants and Letaba since the early 2000s. Refuges in seasonal rivers have been compromised due to the prolonged drought in the Lowveld or dam walls being broken for example the Kannidood Dam on the seasonal Shingwedzi River, KNP. No record in Flag Boshielo Dam on the Olifants River in the last 10 years despite intensive sampling, it is suspected to be extirpated. No information is available for the Cunene River population.

Threats

The northern tributaries of the Olifants River, southern tributaries of the Limpopo River and the mainstem are heavily impacted by obstructions to migrations such as barriers (dams and weirs), over-abstraction and extreme-drought events leading to dried-out rivers. Prolonged droughts in the Lowveld has reduced many seasonal rivers to dry rivers. Further, sedimentation and loss of pools is a threat in the Kruger National Park, South Africa. Over harvesting is a potential threat, as during the dry season and during aggregated spawning events, the species becomes an easy target for subsistence fishers outside the KNP.

Uses and trade

During the dry season and during aggregated spawning events, the species becomes an easy target for subsistence fishers outside the KNP.

Conservation

Detailed surveys of seasonal rivers, control of the illegal use of gill nets in dams and rivers, protection of spawning aggregations from poaching and the compilation of a conservation plan for the species are needed. There is an urgent need for surveys for this species as there are suspected declines due to the lack of observations.

References

[@article{18475,
 author = {Skelton, P.H.},
 title = {A Complete Guide to the Freshwater Fishes of Southern Africa},
 year = {2001}
}
,@article{63287,
 author = {Bills, I.R., Boycott, R.C., Fakudze, M., Khumalo, N., Msibi, J., Scott, L.E.P., Terry, S. and Tweddle, D.},
 title = {Fish and Fisheries of Swaziland (2002-2003). Final report: July 2004},
 year = {2004}
}
,@book{63287,
 author = {Bell-Cross, G. and Minshull, J.L.},
 publisher = {National Museums and Monuments of Zimbabwe},
 title = {The fishes of Zimbabwe},
 year = {1988}
}
,@book{63287,
 address = {Grahamstown},
 author = {Marshall, B. },
 publisher = {South African Institute for Aquatic Biodiversity},
 title = {The fishes of Zimbabwe and their biology},
 year = {2011}
}
,@book{63287,
 address = {Pretoria},
 author = {de Villiers Pienaar U},
 publisher = {National Parks Board of South Africa},
 title = {The Freshwater Fishes of the Kruger National Park: A guide to a group of vertebrate animals from the Superclass Pisces of the Chordate phylum},
 year = {1978}
}
,]

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Red List of South African Species