Barbus hospes

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	ACTINOPTERYGII	CYPRINIFORMES	CYPRINIDAE

Scientific Name:

Barbus hospes

Species Authority:

Barnard, 1938

Common Name/s:

English

–

Namaquab Barb

Assessment Information [top]

Red List Category & Criteria:

Least Concern ver 3.1

Year Assessed:

2007

Assessor/s:

Swartz, E. & Impson, D.

Reviewer/s:

Snoeks, J. (Freshwater Fish Red List Authority) & Darwall, W. (Freshwater Biodiversity Assessment Unit)

Justification:
Although there is no reliable information about population trends, it has been suggested that river regulation in the Orange River system has benefited this species. Therefore, criterion A is not applicable. The occurrence of this species mainly in the mainstream lower Orange River is of concern since any threats from the rest of the system can severely impact on population size and range. However, the lower Orange River is large and the species also occurs in the lower Fish River in Namibia, suggesting that it should be able to survive an catastrophic pollution event upstream. Area of occupancy (AOO) is estimated to be less than 500 km² and because of pollution in the Vaal River, the habitat may be declining. A single pollution event may also severely affect this species because it mostly occurs in the mainstream Orange River. However, the Orange River is quite large, is braided in some places, and the species' extent of occurrence (EOO) is quite large (more than 500 km² in the Orange River, plus the lower Fish River in Namibia). This wide range cannot be considered to be only a few locations and therefore the species does not fully qualify of Endangered under criterion B (only EN B2b(iii)). Population size is expected to be large and indications are that it has actually increased due to river regulation. Criteria C and D therefore do not apply.

Given the wide EOO, and possible population increase due to river regulation, B. hospes is assessed as Least Concern. However, the species should be monitored carefully, especially in relation to habitat declines due to pollution to investigate how this affects population trends and/or the range of the species.

History:

1996	–	Lower Risk/near threatened (Baillie and Groombridge 1996)
1994	–	Rare (Groombridge 1994)
1990	–	Rare (IUCN 1990)
1988	–	Rare (IUCN Conservation Monitoring Centre 1988)

Geographic Range [top]

Range Description:	Orange River below Augrabies falls, including the lower Fish River in Namibia (Skelton 2001).
Countries:	Native: Namibia; South Africa (Northern Cape Province)
Range Map:	(click map to view full version)

Population [top]

Population:	Not assessed, but the regulation of the flow of the lower Orange River by large reservoirs in the Orange and Vaal catchments may have favoured this species (Cambray 1984, Skelton 1987).
Population Trend:	Unknown

Habitat and Ecology [top]

Habitat and Ecology:	Open water in mainstream and backwater areas over sand and rocks (Skelton and Cambray 1981, Cambray 1984). Feeds on zooplankton and aquatic insects (Skelton 2001). They reach maturity in their first year and seem to breed throughout spring and summer till early autumn (September to March). A skewed sex ration of 0.55:1 male to female has been recorded and length frequency distributions suggests that two spawning events may occur in one breeding season (Cambray 1984).
Systems:	Freshwater

Habitat and Ecology:

Open water in mainstream and backwater areas over sand and rocks (Skelton and Cambray 1981, Cambray 1984). Feeds on zooplankton and aquatic insects (Skelton 2001). They reach maturity in their first year and seem to breed throughout spring and summer till early autumn (September to March). A skewed sex ration of 0.55:1 male to female has been recorded and length frequency distributions suggests that two spawning events may occur in one breeding season (Cambray 1984).

Systems:

Freshwater

Threats [top]

Major Threat(s):	Due to its restricted distribution in mostly the lower Orange River, any threat from the rest of the Orange River system can affect this species. Pollution, especially sudden spills, from industrial and mining areas in Mpumalanga, Gauteng, North-west and Freestate provinces can pose a serious threat.

Major Threat(s):

Due to its restricted distribution in mostly the lower Orange River, any threat from the rest of the Orange River system can affect this species. Pollution, especially sudden spills, from industrial and mining areas in Mpumalanga, Gauteng, North-west and Freestate provinces can pose a serious threat.

Conservation Actions [top]

Conservation Actions:	The Ai-Ais/Richtersveld Transfrontier National Park and Augrabies National Park were primarily proclaimed for terrestrial fauna and flora and scenery and relatively ineffective to secure populations of this species due to upstream impacts.

Conservation Actions:

The Ai-Ais/Richtersveld Transfrontier National Park and Augrabies National Park were primarily proclaimed for terrestrial fauna and flora and scenery and relatively ineffective to secure populations of this species due to upstream impacts.

Citation:	Swartz, E. & Impson, D. 2007. Barbus hospes. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 04 February 2012.
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