Actinopterygii (ray-finned fishes) > Perciformes
(Perch-likes) > Cichlidae
(Cichlids) > Pseudocrenilabrinae
Etymology: Oreochromis: Latin, aurum = gold + Greek, chromis = a fish, perhaps a perch (Ref. 45335); esculentus: Esculentus (latin) = edible (Ref. 27292). "The specific name esculenta is suggested, so as to express the fact that this is the important edible commercial species of Lake Victoria." (Ref. 27292, 55055).
Environment / Climate / Range
Freshwater; benthopelagic; depth range 0 - 50 m (Ref. 34291), usually ? - 20 m (Ref. 34290). Tropical; 24°C - 29°C (Ref. 3)
Length at first maturity / Size / Weight / Age
Maturity: Lm 24.8, range 17 - 27 cm
Max length : 50.0 cm SL male/unsexed; (Ref. 2); common length : 31.0 cm SL male/unsexed; (Ref. 34290); max. published weight: 2.5 kg (Ref. 2); max. reported age: 10 years (Ref. 2)
(total): 16 - 18;
soft rays: 9 - 12;
Vertebrae: 30 - 31. Diagnosis: head somewhat pointed; snout with relatively steep forehead; eyes positioned low (Ref. 27292). No enlargement of the jaws in mature males (Ref. 2). Preorbital bone rather shallow, its depth not exceeding 21% head length (Ref. 2, 27292). Pharyngeal bone 33.0-35.5% head length; male genital papilla opening between a pair of often spongy lobes (papilla conical or with a slight distal notch) (Ref. 2). Length:depth ratio of caudal peduncle 0.9-1.15 (Ref. 2, 34290). Males without genital tassel (Ref. 363, 27292, 54836). Body not conspicuously spotted (Ref. 4903, 54836). Male breeding coloration a general reddish colour with black ventral parts and dorsal fin; lappets of dorsal fin not bright red or orange (Ref. 2). No vertical stripes on caudal fin (Ref. 2, 4967). Young and females with Tilapia-mark in soft dorsal fin (Ref. 27292).
Africa: Lake Victoria, Lake Nabugabo, Lakes Kyoga and Kwania, and the Victoria Nile above the Murchison Falls; the Malawa River (Uganda) and Lake Gangu, west of Lake Victoria. This species, which was originally endemic to Lake Victoria, is widely distributed in dams (Ref. 4967). At least one country reports adverse ecological impact after introduction.
Occurs at temperatures ranging from 23.0-28.0 °C (Ref. 3). Tolerant of low oxygen concentrations (<1ppm) (Ref. 3, 48262, 52016) and high levels of carbon dioxide (Ref. 3, 52016). Occasionally forms schools (Ref. 2, 3, 363, 36900, 52061, 55020). Mainly diurnal (Ref. 2). Filter feeder (Ref. 787). Food consist almost entirely of phytoplankton (Ref. 3, 6316), mainly diatoms (Ref. 30832, 34291) but also higher plants (Ref. 27292), and small animals such as insects and their larvae, crustaceans (Ref. 4903, 27292) and worms (Ref. 27292), are taken as well, but they occur less frequently and may contribute to the diet of young fishes (Ref. 4903, 34291). Only diatoms (Ref. 4903, 54979) and some blue-green and green algae (Ref. 361) appear to be digested . Agamous (Ref. 12468), maternal moutbrooder (Ref. 363, 4903, 12468, 27292, 34291, 54840). Excellent taste, firm meat and suitable for sundrying (Ref. 54860).
Reproduction probably triggered by the rains (Ref. 2771), with the time of maximum spawning activity coinciding with the wettest months of the year (Ref. 363). Males form a crater-like spawning nest without a distinct wall (Ref. 27292). The pit is about 30cm in diameter and 10cm deep, and is probably made in the early morning (Ref. 27292). Ovaries show that a female may have a succession of three or more broods in a spawning period; brooding females often shelter in weed beds and swampy places (Ref. 2, 363). Males defend their breeding territory (Ref. 2) for weeks or on and off for several months, while females only make short visits to the spawning grounds and leave the territory immediately after spawning (Ref. 363). Males eat little while actively guarding the nest (Ref. 363). Papyrus swamp channels (Ref. 363, 34921, 55020) and beaches with weed grown swamps (Ref. 34921) function as nursery areas. Young become independent at a length of about 1.5cm (Ref. 2, 363)by which size the yolk sac is occluded and they have strated to feed (Ref. 363), and at about 12cm TL they move from the nursery areas to the open water (Ref. 2).
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. 96402)
CITES (Ref. 94142)
Threat to humans
Potential pest (Ref. 13364)
Fisheries: commercial; aquaculture: experimental
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingMass conversion
Estimates of some properties based on models
Phylogenetic diversity index (Ref. 82805
= 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.01862 (0.01139 - 0.03045), b=3.01 (2.88 - 3.14), based on LWR estimates for species & Genus-body shape (Ref. 93245
Trophic Level (Ref. 69278
): 2.5 ±0.17 se; Based on food items.
Resilience (Ref. 69278
): Medium, minimum population doubling time 1.4 - 4.4 years (tmax=10).
Vulnerability (Ref. 59153
): Low to moderate vulnerability (31 of 100) .