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Oreochromis macrochir

Status_ne_offStatus_dd_offStatus_lc_offStatus_nt_offStatus_vu_onStatus_en_offStatus_cr_offStatus_ew_offStatus_ex_off

Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA ACTINOPTERYGII PERCIFORMES CICHLIDAE

Scientific Name: Oreochromis macrochir
Species Authority: (Boulenger, 1912)
Common Name(s):
English Greenhead Tilapia
Synonym(s):
Chromys chapmanii Castelnau, 1861
Chromys sparmanni Castelnau, 1861
Tilapia alleni Fowler, 1931
Tilapia intermedia Gilchrist & Thompson, 1917
Tilapia sheshekensis Gilchrist & Thompson, 1917

Assessment Information [top]

Red List Category & Criteria: Vulnerable A3e ver 3.1
Year Published: 2007
Date Assessed: 2007-03-01
Assessor(s): Marshall, B.E. & Tweddle, D.
Reviewer(s): Snoeks, J. (Freshwater Fish Red List Authority) & Darwall, W. (Freshwater Biodiversity Assessment Unit)
Justification:
This species is threatened by the alien species Oreochromis niloticus and is displaced by it in areas where the two species occur together (both as aliens) on the Zimbabwean plateau. O. niloticus is being used for aquaculture in the northern Upper Zambezi and will compete with O. macrochir when it spreads through the system. O. niloticus will also inevitably spread into the Okavango, thus the Cunene may remain the only safe refuge for this species. The suspected major decline in O. macrochir of at least 30% in the next 10 years following O. niloticus invasion means the species should be classed as VU under Criterion A3e.

Geographic Range [top]

Range Description: Upper Zambezi, Okavango and Kafue Rivers, as well as the upper Kasai, Lake Bangweulu and the Chambeshi River. It has also been collected from the Revue River in Mozambique (Buzi system), far to the east of its natural distribution and it is possible that this is a relict population (Bell-Cross 1973b). In Zimbabwe, it has been widely distributed through introductions and translocations into many parts of the country. Its introduction into Lake Kariba in 1959 was not particularly successful (Jackson 2000) but it survives in small numbers. It may have colonised the Limpopo River after escaping from the Shashe Dam in Botswana and they have been collected from the Shashe River at Tuli (Minshull) and from a pool downstream of the Shashe/Limpopo confluence (Kleynhans and Hoffman 1992). Also introduced to Komati system in Swaziland (Bills et al. 2004) and spreading to South Africa.
Countries:
Native:
Angola (Angola); Botswana; Namibia; South Africa; Swaziland; Zambia; Zimbabwe
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: A common and widespread species.
Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology: Found in quiet waters along river margins and backwaters, in floodplain habitats and impoundments (Skelton 2001, Tweddle et al. 2004). Feeds mainly on microscopic foods such as algae, especially diatoms, and detritus. Females mouth brood eggs and fry. Breeds in summer, nests grouped into arenas.
Systems: Freshwater

Threats [top]

Major Threat(s): Threatened by the alien species Oreochromis niloticus which is now widely distributed in the Zambezi, Kafue and Limpopo systems.

Conservation Actions [top]

Conservation Actions: Attempts should be made to establish protected areas from which O. niloticus can be excluded and perhaps captive breeding of pure stocks which could be used to restock areas from which this species has disappeared.

Citation: Marshall, B.E. & Tweddle, D. 2007. Oreochromis macrochir. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 22 September 2014.
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