Pseudobarbus calidus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Actinopterygii Cypriniformes Cyprinidae

Scientific Name: Pseudobarbus calidus Barnard, 1938
Common Name(s):
English Clanwilliam Redfin
Barbus calidus Barnard, 1938
Taxonomic Source(s): Skelton, P.H. 2016. Name changes and additions to the southern African freshwater fish fauna. African Journal of Aquatic Science 41(3): 345-351.
Taxonomic Notes: 'Pseudobarbus' calidus formerly belonged to the genus Barbus, but following the work of Yang et al. (2015), the genus Pseudobarbus was expanded to include additional species resulting in the renaming of 'Pseudobarbuscalidus (Skelton 2016).

Assessment Information [top]

Red List Category & Criteria: Vulnerable B2ab(ii,iii,v) ver 3.1
Year Published: 2017
Date Assessed: 2007-03-01
Assessor(s): Impson, D. & Swartz, E.R.
Reviewer(s): Snoeks, J. & Darwall, W.R.T.
Anecdotal reports indicated that the major declines happened shortly after the introduction and spread of Smallmouth Bass into mainstream habitat, probably from 1940 to 1950. Some tributary sub-populations e.g., Jan Dissels River have declined substantially since the 1970s, but recent declines are not of the order to warrant application of criterion A. The restricted range threshold for Critically Endangered under criterion B applies because of the small size of its area of occupancy, mostly in small streams that are 2 to 3 m wide (area of occupancy (AOO) is 53 km², using a 1 km² grid). Increasing levels of threat and the severely fragmented nature of populations, with the major threat being Smallmouth Bass could qualify the species as CR B2ab(ii,iii,v). However, as several of the populations are large enough to survive without the need for immigration the population can not be considered to be truly fragmented following the definitions used for Red Listing species. Finally, given that the species is thought to only be known from seven separate locations: subpopulations are secured by barriers at the Ratels, Boskloof, Rondegat, Biedou, Tra Tra and Matjies leaving the riverine subpopulation vulnerable to the single threat of Micropterus dolomieu (Oudste-Thee-Noordhoeks-Jan Dissels-Dwars-Eselbank-Breekkrans) it qualifies as VU B2ab(ii,iii,v).
Previously published Red List assessments:

Geographic Range [top]

Range Description:Endemic to the Olifants River System in the Western Cape Province of South Africa (Skelton 2001). It has been recorded in the mainstream of the Upper Olifants branch of this system near Clanwilliam and Keerom. It is currently found in the Ratels, Oudste, Thee, Noordhoeks, Boontjies, Boskloof, Rondegat, Jan Dissels and Dwars tributaries of the Upper Olifants branch and the Biedou, Tra Tra, Eselbank, Driehoeks and Breekkrans tributaries of the Doring River. Its distribution range has thus shrunk substantially, primarily due to alien fish invasion.
Countries occurrence:
South Africa (Western Cape)
Additional data:
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:It is relatively abundant in good habitat where alien fishes are absent.
Current Population Trend:Decreasing
Additional data:

Habitat and Ecology [top]

Habitat and Ecology:Favours pools and runs in clear, acidic, perennial mountain streams (Impson and Swartz 2002). Feeds almost exclusively on Baetidae, Chironomidae and Formicidae and has an extended breeding season with ripe gonads from November to January (Nthimo 1997). Forms breeding aggregations in shallow slow-flowing pools with spawning occurring in rock crevices and amongst boulders (Impson and Swartz 2002).

Threats [top]

Major Threat(s): The most important threat is the introduction of invasive alien fishes. The introduction of Micropterus dolomieu into the system in the 1930’s for angling purposes is regarded as the most severe threat, with predatory impacts also from Lepomis macrochirus and Oncorhynchus mykiss. Tilapia sparrmani is a competitor for food. The other major threat is habitat degradation caused primarily by intensive farming of deciduous fruit and citrus. The major impacts are over-abstraction of water during the dry summer months and the planting of orchards within the 1:1 yr floodline of the river. The absence of a natural riparian zone, and hence buffer area between the river and intensive agriculture allows fertilisers and copper- based pesticides easy access to the aquatic environment.

Conservation Actions [top]

Conservation Actions: The distribution range of Pseudobarbus calidus fortunately includes proclaimed protected areas, but most is within privately owned land. The upper reaches of the Boskloof, Jan Dissels, Noorhoek and Rondegat rivers are within the Cederberg Wilderness Area whereas the middle Matjies River is within the Matjies River Nature Reserve. Although these rivers may be within protected areas, this does imply that they are free of invasive alien fishes or from future invasion. The species is listed as endangered by the provincial Nature Conservation Ordinance, preventing capture of the species. Several of the above rivers have been identified as a priority freshwater environment for fish conservation (Impson et al. 1999). Conservation staff and researchers have increased awareness of the uniqueness of the Rondegat river. Awareness of the species has been enhanced by displays at prominent public aquaria in Clanwilliam, Cape Town and Jonkershoek.

Amended [top]

Amended reason: Due to recent taxonomic research conducted by Yang et al. (2015) and Skelton (2016), this species has been moved from the genus Barbus, to the genus Pseudobarbus.

Citation: Impson, D. & Swartz, E.R. 2017. Pseudobarbus calidus. (amended version published in 2007) The IUCN Red List of Threatened Species 2017: e.T2562A114982048. . Downloaded on 21 October 2017.
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