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Barbus serra

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA ACTINOPTERYGII CYPRINIFORMES CYPRINIDAE

Scientific Name: Barbus serra
Species Authority: Peters, 1864
Common Name(s):
English Clanwilliam Sawfin

Assessment Information [top]

Red List Category & Criteria: Endangered B2ab(iii,v) ver 3.1
Year Published: 2007
Date Assessed: 2007-03-01
Assessor(s): Impson, D. & Swartz, E.
Reviewer(s): Snoeks, J. (Freshwater Fish Red List Authority) & Darwall, W. (Freshwater Biodiversity Assessment Unit)
Justification:
Anecdotal reports indicated that Barbus serra numbers declined sharply between 1930 and 1970, after the introduction of smallmouth bass into the Olifants River system. Without supporting data to show severe declines since the 1970s, criterion A can not be applied. Criterion B applies because of the small size of its area of occupancy (generally small streams that are 2 to 3 m wide), increasing levels of threats and the low number of locations (five), with the major threat being smallmouth bass, which affects most subpopulations. The actual area occupied has been worked out to be 5.7 km². Area of occupancy (AOO), using a 1 km² grid overlay is calculated as 203 km². Locations have been identified as those subpopulations protected by barriers to invasive aliens, namely Ratels, Biedou, Tra Tra and Driehoeks and the Upper Olifants-Jan Dissels-Oorlogskloof-Doring which is treated as one location because its "open" nature and subsequent risk to a single invasion by alien species. The species therefore qualifies as Endangered under B2ab(iii,v).
History:
1996 Endangered
1994 Vulnerable (Groombridge 1994)
1990 Vulnerable (IUCN 1990)
1988 Vulnerable (IUCN Conservation Monitoring Centre 1988)

Geographic Range [top]

Range Description: Endemic to the Olifants River System, Western Cape Province, South Africa (Skelton 2001). The species was originally widespread in the system, inhabiting both mainstream and tributary areas (van Rensburg 1966, Gaigher 1973, Paxton et al. 2002). The introduction of Micropterus dolomieu in the 1940s, and its subsequent dominance of mainstream environments, caused recruitment collapse of Barbus serra and localised extinctions in the middle and lower Olifants River and from several tributaries.
Countries:
Native:
South Africa (Western Cape)
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Currently healthy populations of Barbus serra are characterised by good recruitment and large numbers of fish (e.g., upper Olifants, Ratels and Oorlogskloof populations). Where alien fish, especially bass (Miropterus) predominate, this species is present in very low numbers of adult fish (e.g., Doring River), or is locally extinct.
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: Common in rivers of variable size with good habitat and an absence of alien fishes. Juveniles are primarily pool dwellers (Gore et al. 1991) of foothill river zones whereas adults prefer larger, deeper pools in transitional zones of rivers. The Clanwilliam sawfin is omnivorous, feeding primarily on aquatic insects (van Rensburg 1966). It is a relatively large cyprinid attaining 3.04 kg (Skelton 2001). It is a slow growing species with 1,3 and 10 year old fish attaining 90, 200 and 390 mm SL respectively (van Rensburg 1966). Breeds from late spring (October) to summer (December), with gathering small schools of adults over cobble beds in shallow riffles.
Systems: Freshwater

Threats [top]

Major Threat(s): Co-exists with Labeobarbus capensis and faces the same threats, namely predation by and competition with invasive alien fishes and habitat degradation by ecologically unsustainable agricultural development. Micropterus dolomieu are regarded as the most serious invader.

Conservation Actions [top]

Conservation Actions: Good populations within the Cederberg Wilderness Area, Matjies River and Oorlogskloof Nature reserves. However, several rivers in these protected areas that have Barbus serra, are invaded by alien fishes, including Micropterus dolomieu. The species is listed as endangered by the provincial Nature Conservation Ordinance making catch and release compulsory for anglers. Barbus serra has been successfully cultured at the Clanwilliam Yellowfish station, although few fish were produced and stocked compared to the Clanwilliam yellowfish. The Greater Cederberg Biodiversity Corridor (GCBC) was established in 2004 to promote partnerships between CapeNature, the provincial conservation agency, and private land-owners with highly conservation worthy land. Ecologically sustainable use of rivers and associated fauna is an important component of the GCBC, and considerable resources are allocated annually to remove alien vegetation that is invading and degrading rivers.

Citation: Impson, D. & Swartz, E. 2007. Barbus serra. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 27 August 2014.
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