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Oreochromis mossambicus
– Near Threatened
Taxonomy
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Kingdom:
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ANIMALIA
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Phylum:
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CHORDATA
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Class:
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ACTINOPTERYGII
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Order:
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PERCIFORMES
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Family:
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CICHLIDAE
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Scientific Name:
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Oreochromis mossambicus
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Species Authority:
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(Peters, 1852)
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Synonym/s:
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Chromis dumerilii Steindachner, 1864 Chromis natalensis Weber, 1897 Chromis vorax Pfeffer, 1893 Tilapia arnoldi Gilchrist & Thompson, 1917
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Common Name/s:
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| English | — | MOZAMBIQUE TILAPIA |
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Assessment Information
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Red List Category & Criteria:
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NT ver 3.1 (2001)
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Year Assessed:
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2007
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Assessor/s:
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Cambray, J. & Swartz, E.
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Evaluator/s:
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Tweddle, D. (Freshwater Fish Red List Authority) & Darwall, W. (Freshwater Biodiversity Assessment Unit)
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Justification:
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Threatened by hybridization with the rapidly spreading Oreochromis niloticus. Oreochromis niloticus is being spread by anglers and for aquaculture. Hybridization is already occurring throughout the northern part of the species' range, with most of the evidence coming from the Limpopo River system. In terms of locations the threat of Oreochromis niloticus is widespread, but probably more than 50% of the locations are not yet affected. Given the rapid spread of O. niloticus it is anticipated that this species will qualify as threatened under Criterion A due to rapid population decline through hybridization. The species is therefore assessed as Near Threatened.
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Geographic Range
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Range Description:
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Lower Zambezi, Lower Shire and coastal plains from Zambezi delta to Algoa Bay. Occurs southwards to the Bushmans River in the eastern Cape and in the Transvaal in the Limpopo system (Skelton 2001). Widely dispersed beyond this range to inland regions and to the south west and west coastal rivers including the lower Orange and rivers of Namibia. Introduced to tropical and warm temperate localities throughout the world.
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Range Map:
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 (click for detailed map)
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Countries:
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Native:
Malawi; Mozambique; South Africa (Eastern Cape Province, KwaZulu-Natal); Swaziland; Zambia; Zimbabwe
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Population
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Population:
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Common and widespread through south eastern Africa.
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Population Trend:
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Habitat and Ecology
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Habitat and Ecology:
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Occurs in all but fast-flowing waters; thrives in standing waters. Further south in its range it is most common in blind estuaries and coastal lakes where it tolerates brackish and marine environments. Feeds on algae, especially diatoms, and detritus, large individuals also take insects and other invertebrates. Breeds in summer, females raising multiple broods every 3 to 4 weeks during a season. Males construct a saucer-shaped nest on sandy bottoms: the female mouthbroods the eggs, larvae and small fry. Juveniles shoal in shallow water. Prone to stunting under adverse or crowded conditions (Skelton 2001).
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System:
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Freshwater
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List of Habitats:
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| 5.1 | Wetlands (inland) - Permanent Rivers/Streams/Creeks (includes waterfalls) |
| 5.2 | Wetlands (inland) - Seasonal/Intermittent/Irregular Rivers/Streams/Creeks |
| 5.4 | Wetlands (inland) - Bogs, Marshes, Swamps, Fens, Peatlands |
| 5.5 | Wetlands (inland) - Permanent Freshwater Lakes (over 8ha) |
| 5.6 | Wetlands (inland) - Seasonal/Intermittent Freshwater Lakes (over 8ha) |
| 5.7 | Wetlands (inland) - Permanent Freshwater Marshes/Pools (under 8ha) |
| 5.8 | Wetlands (inland) - Seasonal/Intermittent Freshwater Marshes/Pools (under 8ha) |
| 5.13 | Wetlands (inland) - Permanent Inland Deltas |
| 5.14 | Wetlands (inland) - Permanent Saline, Brackish or Alkaline Lakes |
| 5.15 | Wetlands (inland) - Seasonal/Intermittent Saline, Brackish or Alkaline Lakes and Flats |
| 5.16 | Wetlands (inland) - Permanent Saline, Brackish or Alkaline Marshes/Pools |
| 5.17 | Wetlands (inland) - Seasonal/Intermittent Saline, Brackish or Alkaline Marshes/Pools |
| 9.10 | Marine Neritic - Estuaries |
| 12.5 | Marine Intertidal - Salt Marshes (Emergent Grasses) |
| 13.4 | Marine Coastal/Supratidal - Coastal Brackish/Saline Lagoons/Marine Lakes |
| 13.5 | Marine Coastal/Supratidal - Coastal Freshwater Lakes |
| 15.1 | Artificial/Aquatic - Water Storage Areas (over 8ha) |
| 15.2 | Artificial/Aquatic - Ponds (below 8ha) |
| 15.3 | Artificial/Aquatic - Aquaculture Ponds |
| 15.7 | Artificial/Aquatic - Irrigated Land (includes irrigation channels) |
| 15.8 | Artificial/Aquatic - Seasonally Flooded Agricultural Land |
| 15.9 | Artificial/Aquatic - Canals and Drainage Channels, Ditches |
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Threats
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Threats:
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The Nile tilapia, Oreochromis niloticus, is invading its natural range in the Zambezi and Limpopo systems. Hybridisation is occurring in the Limpopo system and pure O. mossambicus are likely to become extirpated in those systems through competition and hybridisation.
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List of Threats:
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| 2.1 | Invasive alien species (directly affecting the species) - Competitors (present, future) |
| 2.3 | Invasive alien species (directly affecting the species) - Hybridizers (present, future) |
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Conservation Actions
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Conservation Actions:
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River systems not yet invaded by Nile tilapia must be protected from deliberate and accidental introductions of that species.
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List of Conservation Actions:
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| 2.2 | Communication and Education - Awareness (needed) |
| 3.2 | Research actions - Population numbers and range (needed) |
| 3.5 | Research actions - Threats (needed) |
| 3.8 | Research actions - Conservation measures (needed) |
| 3.9 | Research actions - Trends/Monitoring (needed) |
| 4.4.1 | Habitat and site-based actions - Protected areas - Identification of new protected areas (needed) |
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Bibliography
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Bibliography:
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Skelton, P.H. 2001. A Complete Guide to the Freshwater Fishes of Southern Africa. Struik Publishers, Cape Town, South Africa.
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