Red List of South African Species

Alternatively, Explore species
| National Red List categories | Partners |
Vulnerable (VU)
A4ae
Assessors: Roger Bills
Contributors: Jim Cambray Ernst Swartz
Facilitators: Dewidine Van Der Colff
Reviewers: Olaf Weyl

Rationale

In its native range Mozambique Tilapia is Oreochromis mossambicus threatened by hybridisation with the rapidly spreading Nile Tilapia (Oreochromis niloticus), that is being spread by anglers and for aquaculture. Hybridisation 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 Nile Tilapia is widespread, at least 30% of the locations have been affected by hybridisation in the past, and further impacts are projected in future that would result in more than 30% rapid population reduction. The species has an estimated generation length of seven years, and the observed reduction in population size has taken place recently, at least in the last 14 years. Since there are no plans in place to prevent further introductions of Nile Tilapia, given its rapid spread and population decline through hybridisation, the species is assessed as Vulnerable A4ae.

Distribution

This species occurs in the Lower Zambezi, Lower Shire and coastal plains from Zambezi delta to Algoa Bay, South Africa. Occurs southwards to the Bushmans River in the Eastern Cape, and northwards from Kwazulu-Natal and in the Limpopo River System (Gauteng, North West, Mpumalanga and Limpopo Provinces) (Skelton 2001). It is widely dispersed beyond this range to inland regions and to the southwest and west coastal rivers including the lower Orange and rivers of Namibia. It has been introduced to tropical and warm temperate localities throughout the world where it is often considered invasive.

Population trend

Trend

The species has a calculated generation length of seven years, based on a longevity of 11 years and age of first reproduction after one year (Noakes and Balon 1982). This species is common and widespread throughout southeastern Africa, however population reductions have been observed due to hybridisation and competition with Nile Tilapia (Moralee et al. 2000, D’Amato et al. 2007, Tweddle and Wise 2007, Firmat et al. 2013, Deines et al. 2014).

Threats

The Nile Tilapia (Oreochromis niloticus), is invading its natural range in the Zambezi and Limpopo rivers systems. Hybridisation is occurring in the Limpopo River System and pure Mozambique Tilapia (O. mossambicus) are likely to become extirpated in those systems through competition and hybridisation (Moralee et al. 2000, D’Amato et al. 2007, Zengeya et al. 2011, Firmat et al. 2013, Zengeya et al. 2013a, Zengeya et al. 2013b, Deines et al. 2014).

Uses and trade

No information is available on the use or trade of this species.

Conservation

To protect the genetic integrity of Mozambique Tilapia, river systems in its native range that have not yet been invaded by Nile Tilapia and other non-native Oreochromis species must be protected from deliberate and accidental introductions.

References 

[@article{18475,
 author = {Skelton, P.H.},
 title = {A Complete Guide to the Freshwater Fishes of Southern Africa},
 year = {2001}
}
,@inbook{63338,
 author = {},
 booktitle = {Life histories of tilapias: an evolutionary perspective},
 editor = {Noakes, D.G.L. and Balon, E.K.},
 pages = {61--82},
 publisher = {CLARM Conf. Proc. 7.},
 title = {The biology and culture of tilapias},
 year = {1982}
}
,@article{63338,
 author = {D’Amato ME, Esterhuyse MM, van Der Waal BCW, Brink D & Volckaert FAM.},
 journal = {Conservation Genetics},
 pages = {475–488},
 title = {Hybridization and phylogeography of the Mozambique tilapia Oreochromis mossambicus in southern Africa evidenced by mitochondrial and microsatellite DNA genotyping},
 volume = {8.0},
 year = {2007}
}
,@article{63338,
 author = {Deines AM, Bbole I, Katongo C, Feder JL & Lodge DM},
 journal = {African Journal of Aquatic Science},
 number = {1},
 pages = {23--34},
 title = {Hybridization of native Oreochromis species (Cichlidae) and the introduced Nile tilapia (O. niloticus) in the Kafue river, Zambia},
 volume = {39.0},
 year = {2014}
}
,@article{63338,
 author = {Firmat, C., Alibert, P., Losseau, M., Baroiller, J-F. & Schliewen, U.K.},
 journal = {Plos One },
 pages = {1--12},
 title = {Successive invasion-mediated interspecific hybridizations and population structure in the endangered cichlid Oreochromis mossambicus.},
 volume = {8.0},
 year = {2013}
}
,@article{63338,
 author = {Moralee RD, van der Bank FH & van der Waal BCW},
 journal = {Water SA},
 pages = {263–268},
 title = {Biochemical genetic markers to identify hybrids between the endemic Oreochromis mossambicus and the alien species, O. niloticus (Pisces: Cichlidae).},
 volume = {26.0},
 year = {2000}
}
,@article{63338,
 author = {Zengeya TA, Booth AJ, Bastos ADS & Chimimba CT.},
 journal = {Environmental Biology of Fishes},
 pages = {479–489.},
 title = {Trophic interrelationships between the exotic Nile tilapia, Oreochromis niloticus and indigenous tilapiine cichlids in a subtropical African river system (Limpopo River, South Africa).},
 volume = {92.0},
 year = {2011}
}
,@article{63338,
 author = {Zengeya TA, Robertson MP, Booth AJ & Chimimba CT.},
 journal = {Biological Invasions},
 pages = {1507--1521},
 title = {Ecological niche modeling of the invasive potential of Nile tilapia Oreochromis niloticus in African river systems: concerns and implications for the conservation of indigenous congenerics},
 volume = {15.0},
 year = {2013}
}
,@article{63338,
 author = {Zengeya TA, Robertson MP, Booth AJ & Chimimba CT.},
 journal = {Aquatic Conservation: Marine and Freshwater Ecosystems},
 pages = {51--64},
 title = {A qualitative ecological risk assessment of the invasive Nile tilapia, Oreochromis niloticus in a subtropical African river system (Limpopo River, South Africa)},
 volume = {23.0},
 year = {2013}
}
,@article{63338,
 author = {Tweddle, D. and Wise, R.M.},
 journal = {Final Report prepared for the Global Invasive Species Programme. CSIR Report Number CSIR/NRE/RBSD/ER/2007/0044/C, Appendix 3: 43 pp.},
 pages = {1--43},
 title = {Nile Tilapia (Oreochromis niloticus). In Wise, R.M., van Wilgen, B.W., Hill, M.P., Schulthess, F., Tweddle, D., Chabi-Olay, A. & Zimmerman, H.G. (2007). The economic impact and appropriate management of selected invasive alien species on the African continent.},
 year = {2007}
}
,]
Send feedback about this assessment to SANBI

Lead agencies, Partners and Funders

See the partners page