Actinopteri (ray-finned fishes) > Cichliformes
(Cichlids, convict blennies) > Cichlidae
(Cichlids) > Pseudocrenilabrinae
Etymology: Oreochromis: Latin, aurum = gold + Greek, chromis = a fish, perhaps a perch (Ref. 45335); mortimeri: Named for M.A.E. Mortimer, a fish culturist who conducted a great deal of productive fish culture research in Zambia between 1951 and 1965 (Ref. 13337).
More on author: Trewavas.
Environment: milieu / climate zone / depth range / distribution range
Freshwater; benthopelagic. Tropical; 10°S - 19°S
Africa: Middle Zambezi and its tributaries, including Luangwa River (except probably the upper reaches of its tributaries Lunsemfwa and Mulungwishi above the escarpment), Hunyani River and Lake Kariba (Ref. 5166). Introduced to Kipopo and the Lufira River (upper Congo River basin) in Democratic Republic of the Congo (Ref. 1978).
Length at first maturity / Size / Weight / Age
Maturity: Lm 22.0  range ? - ? cm
Max length : 48.0 cm TL male/unsexed; (Ref. 5309); max. published weight: 4.1 kg (Ref. 13337); max. reported age: 8 years (Ref. 2)
Morphology | Morphometrics
(total): 16 - 17;
soft rays: 10 - 12;
Vertebrae: 29 - 30. Diagnosis: jaws greatly enlarged in mature males; scales in 2-3 rows on cheek; caudal peduncle relatively shorter than in O. mossambicus (Ref. 2). In life greenish grey (Ref. 2), green-blue (Ref. 52307) or grey-blue with a darker spot on each scale (Ref. 2, 52307). Females and immature males often with 1-3 dark mid-lateral blotches (Ref. 2, 52307), which may appear only as the fish dies (Ref. 2). Breeding males: predominantly iridescent blue-green to bronze (Ref. 2, 52307), with iridescent spots on dorsal and caudal fins (Ref. 2), a dorsal fin with a red edge that is not as pronounced as in O. mossambicus, and a narrow (as opposed to wide) red band at posterior end of caudal fin (Ref. 12524, 13337).
Forms schools (Ref. 2, 54048). Is mainly diurnal; salt-tolerant (Ref. 2). Feeds mainly on (filamentous) algae (Ref. 2, 12524, 13337, 52307, 54048) and diatoms, as well as higher plants (Ref. 2, 52307), dipterous larvae, cladocerans, copepods (Ref. 2), aquatic and terrestrial insects, shrimps, worms (Ref. 12524, 13337, 54048) and mollusks (Ref. 54048). Mouthbrooder; spawns several times per year (Ref. 12524, 13337, 54048).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Nest a saucer-shaped depression with a raised mound in the middle (Ref. 12524, 13337), made by the male in a breeding arena in shallow water down to about 4m (Ref. 54048). Females are lured to these through male courtship displays; female collects eggs in mouth after spawning and fertilisation, and moves off; mouthbrooding females may shoal together and do not feed at this time; eggs hatch after about ten days but remain in the mouth for a further few days; juveniles make short feeding sorties once the storage yolk is used up, but seldom stray far and dart into her mouth when danger threatens; after about another 10 days young are released in warm shallow water in the margins (nursery areas), where they feed independently in small shoals (Ref. 54048). Young released from mouthbrooding female are about 1cm long (Ref. 2). Female returns to the breeding arena where she spawns again (Ref. 54048).
Trewavas, E., 1983. Tilapiine fishes of the genera Sarotherodon, Oreochromis and Danakilia. British Mus. Nat. Hist., London, UK. 583 p. (Ref. 2)
IUCN Red List Status (Ref. 125652)
Threat to humans
Fisheries: commercial; aquaculture: experimental; gamefish: yes
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingNutrientsMass conversion
Estimates based on models
Phylogenetic diversity index (Ref. 82804
= 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.02042 (0.00978 - 0.04261), b=3.01 (2.83 - 3.19), in cm total length, based on LWR estimates for this species & (Sub)family-body (Ref. 93245
Trophic level (Ref. 69278
): 2.2 ±0.0 se; based on diet studies.
Generation time: 4.3 ( na - na) years. Estimated as median ln(3)/K based on 1 growth studies.
Resilience (Ref. 120179
): Medium, minimum population doubling time 1.4 - 4.4 years (tmax=8).
Fishing Vulnerability (Ref. 59153
): Moderate vulnerability (39 of 100).