Kariba Tilapia
CR

Kariba Tilapia

Oreochromis mortimeri

Declining

Photo: Wikimedia Commons (CC) via https://en.wikipedia.org/wiki/Oreochromis_mortimeri

Overview

Oreochromis mortimeri, the Kariba tilapia or kurper bream, is a species of cichlid, formerly classified as a Tilapiine cichlid but now placed in the genus Oreochromis, the type genus of the tribe Oreochromini of the subfamily Pseudocrenilabrinae. It is found in the rivers of south central Africa especially the middle Zambezi where it is endangered by the spread of invasive congener Oreochromis niloticus.

Oreochromis mortimeri faces severe population decline primarily due to hybridization with introduced tilapia species, particularly O. niloticus, which has led to genetic pollution of native stocks. Overfishing and habitat degradation from agricultural runoff and sedimentation have further reduced remaining populations. The species' restricted range in specific river systems makes it particularly vulnerable to localized threats and environmental changes.

Threat summary

Habitat

Oreochromis mortimeri inhabits freshwater river systems and associated floodplains in the upper Zambezi River basin. The species prefers shallow, vegetated areas with sandy or muddy substrates where it can establish breeding territories and feed on algae and detritus.

Wetlands (inland) - Permanent freshwater lakes· major

Frequently asked questions

Why is Kariba Tilapia classified as Critically Endangered?
Kariba Tilapia is classified as Critically Endangered — facing an extremely high risk of extinction in the wild — because population sizes are very small, declining sharply, or restricted to a tiny range. Oreochromis mortimeri faces severe population decline primarily due to hybridization with introduced tilapia species, particularly O. niloticus, which has led to genetic pollution of native stocks. Overfishing and habitat degradation from agricultural runoff and sedimentation have further reduced remaining populations. The species' restricted range in specific river systems makes it particularly vulnerable to localized threats and environmental changes.
Where does Kariba Tilapia live?
Kariba Tilapia occurs in Angola, Botswana, Congo - Kinshasa, Mozambique, South Africa, and Zambia (plus 1 other countries). Country-level distribution data is sourced from the IUCN Red List and cross-referenced with GBIF occurrences.
What are the main threats to Kariba Tilapia?
The main threats to Kariba Tilapia are 8.1, ai-1, ai-2, and ai-3. The full IUCN-classified threat record for this species is detailed on the species page.

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