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Cichliformes (Cichlids, convict blennies) >
Cichlidae (Cichlids) > Pseudocrenilabrinae
Etymology: Oreochromis: Latin, aurum = gold + Greek, chromis = a fish, perhaps a perch (Ref. 45335).
More on author: Linnaeus.
Environment: milieu / climate zone / depth range / distribution range
Ekologi
; sötvatten; brackvatten bentopelagisk; flodvandrande (Ref. 51243); djupintervall 0 - 20 m (Ref. 32849), usually ? - 20 m (Ref. 34290). Tropical; 14°C - 33°C (Ref. 3); 32°N - 5°S, 17°W - 38°E
Africa: naturally occurring in coastal rivers of Israel (Ref. 5166), Nile basin (including lake Albert, Edward and Tana), Jebel Marra, Lake Kivu, Lake Tanganyika, Awash River, various Ethiopian lakes, Omo River system, Lake Turkana, Suguta River and Lake Baringo (Ref. 2). In West Africa natural distribution covers the basins of the Senegal, Gambia, Volta, Niger, Benue and Chad, with introduced specimens reported from various coastal basins (Ref. 53405). Widely introduced for aquaculture, with many existing strains. Several countries report adverse ecological impact after introduction. The following subspecies were previously recognized: Oreochromis niloticus baringoensis, Oreochromis niloticus cancellatus, Oreochromis niloticus eduardianus, Oreochromis niloticus filoa, Oreochromis niloticus niloticus, Oreochromis niloticus sugutae, Oreochromis niloticus tana and Oreochromis niloticus vulcani.
Length at first maturity / Size / Vikt / Age
Maturity: Lm 18.6, range 6 - 28 cm
Max length : 60.0 cm SL hane/ej könsbestämd; (Ref. 4967); publicerad maxvikt: 4.3 kg (Ref. 40637); rapporterad maxålder: 9 år (Ref. 164)
Taggstrålar i ryggfenan (totalt) : 15 - 18; Mjukstrålar i ryggfenan (totalt) : 11 - 13; Taggstrålar i analfenan: 3; Mjukstrålar i analfenan: 9 - 11; Ryggkotor: 30 - 32. Diagnosis: A large deep-bodied tilapia, with a relatively small head (Ref. 118638). Jaws of mature male not greatly enlarged, length of lower jaw 29-37% of head length; genital papilla of breeding male not tassellated (Ref. 2). Body depth 36-50% of SL (Ref. 28714). Most distinguishing characteristic is the presence, at all life stages, of regular vertical stripes throughout depth of caudal fin (Ref. 4967, 53405, 118638). In smaller fishes, these are relatively wide and form an arc, and start at the base of the caudal fin (Ref. 118638). Males are bluish pink, sometimes with a dark throat, belly, anal and pelvic fins; females are usually brownish, silvery/white beneath with around 10 thin vertical bars (Ref. 118638).
Occurs in a wide variety of freshwater habitats like rivers, lakes, sewage canals and irrigation channels (Ref. 28714). Does not do well in pure salt water, but is able to survive in brackish water (Ref. 52307). Mainly diurnal. Feeds mainly on phytoplankton or benthic algae. Additionally, insect larvae are of some importance, as are aufwuchs and detritus; juveniles tend to be more omnivorous than adults (Ref. 52307). Oviparous (Ref. 205), ovophilic (Ref. 52307). A maternal mouthbrooder (Ref. 2, 28714, 52307, 118638), males dig simple pits in shallow water (Ref. 118638). May mature early (about 11 cm TL females, 14 cm TL males) (Ref. 28714). Globally, the most important tilapia species in fish farming and supports major capture fisheries where established; generally highly invasive and known to hybridise with many other Oreochromis species and for this reason further stocking has been banned in a number of countries, e.g. South Africa, Malawi and Zambia (Ref. 118638). Extended temperature range 8-42 °C, natural temperature range 13.5 - 33 °C (Ref. 3). Maximum depth from Ref. 34290. Marketed fresh and frozen (Ref. 9987).
Sexual maturity is reached at 3-6 months depending on temperature, reaching about 30 g. Reproduction occurs only when temperatures are over 20°C. Several yearly spawnings every 30 days. Females incubate eggs inside their mouths (approximately for a week) where larvae hatch and remain until the vitellus is reabsorved. Egg size 1.5 mm, larval length at hatching 4 mm.
Spawns in firm sand in water from 0.6 to 2 m deep of lakes (Ref. 2) and inshore waters (Ref. 55624). Males set up and defend territory which are visited by the females. Courtship lasts several hours. A single male probably fertilises the eggs of more than one female (Ref. 55624). Eggs are shed in batches in shallow nest and fertilized by male. Each batch of eggs is picked up into oral cavity by female. Females solely involved in broodcare. Female carries up to 200 eggs in her mouth where the larvae hatch and remain until after the yolk-sac is absorbed.
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. 130435: Version 2024-1)
Threat to humans
Potential pest
Human uses
Fiskeri: kommersiellt viktig; Vattenbruk: kommersiell
Verktyg
Special reports
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Estimates based on models
Phylogenetic diversity index (Ref.
82804): PD
50 = 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.01778 (0.01491 - 0.02121), b=2.99 (2.95 - 3.03), in cm total length, based on LWR estimates for this species (Ref.
93245).
Trofisk nivå (Ref.
69278): 2.0 ±0.0 se; based on diet studies.
Generation time: 2.9 (2.2 - 3.9) years. Estimated as median ln(3)/K based on 26
growth studies.
Resiliens (Ref.
120179): Mellan, lägsta populationsfördubblingstid 1,4-4,4 år (K=0.14-0.41; tm=1-2; tmax=9; Fec < 1,000).
Fishing Vulnerability (Ref.
59153): Low to moderate vulnerability (30 of 100).
Nutrients (Ref.
124155): Calcium = 40.6 [5.6, 397.5] mg/100g; Iron = 3.21 [1.27, 7.98] mg/100g; Protein = 17.7 [15.8, 19.6] %; Omega3 = 0.144 [0.021, 1.033] g/100g; Selenium = 279 [33, 2,176] μg/100g; VitaminA = 0.877 [0.050, 12.397] μg/100g; Zinc = 5.76 [1.85, 10.72] mg/100g (wet weight); based on
nutrient studies.
