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Cichlidae (Cichlids) > Pseudocrenilabrinae
Etymology: Oreochromis: Latin, aurum = gold + Greek, chromis = a fish, perhaps a perch (Ref. 45335).
More on author: Trewavas.
Issue
Turner and Robinson (1991) (Ref. 55079) conclude that Oreochromis saka is a junior synonym of O. karongae (also Ref. 6150), although Turner et al. (1989) (Ref. 40180) reported O. squamipinnis to be most similar to O. saka and O. karongae the most divergent (Ref. 55954).
Environment: milieu / climate zone / depth range / distribution range
Ecology
Freshwater; benthopelagic; depth range 0 - 50 m (Ref. 118638), usually 0 - 10 m (Ref. 5595). Tropical; 22°C - 28°C; 8°S - 15°S
Africa: Lake Malawi and its catchment (Ref. 2, 5166, 118630, 118638), including crater lake Itamba and Ikapu (Ref. 118638).
Length at first maturity / Size / Weight / Age
Maturity: Lm 28.9, range 20 - 38 cm
Max length : 42.0 cm TL male/unsexed; (Ref. 6150); 38.0 cm SL (female)
Dorsal spines (total): 15 - 17; Dorsal soft rays (total): 10 - 12; Anal spines: 3; Anal soft rays: 8 - 10; Vertebrae: 30 - 32. Diagnosis: A heavily-built large tilapia species with a wide rounded head and short jaws; individuals vary a lot in dentition, with some having very wide bands of jaw teeth (Ref. 118638). Head length 30.8-36.0% of standard length; lower pharyngeal with large toothed area with straight or slightly convex sides; median length of pharyngeal bone 1.14-1.32 times its width and 38.2-42.2% of head length; blade 1.0-1.7 times median length of toothed area; length of lower jaw 28.4-34.5% of head length; teeth of jaws in 4-6 rows (Ref. 2). Females and juveniles with greyish-brown bodies and 4-5 vertical bars (Ref. 118638). Males are black with a white margin to the dorsal and tailfins; the genital tassel can be long and branched and pinkish to bright yellow (Ref. 2, 118638). It is one of the 'chambo' group Oreochromis from the Lake Malawi catchment; females and non-territorial males cannot be reliably distinguished from those of Oreochromis squamipinnis; females and non-territorial males from Lake Ikapu are a bright golden colour (Ref. 118638).
It is found in all kinds of habitats; it has been observed in shallow vegetated bays, in intermediate habitats, over sand, and in purely rocky biotopes (Ref. 5595). At most locations it is found at shallow levels, rarely deeper than 10 metres (Ref. 5595), but it can be present from the surface waters to depths of 40-50m (Ref. 118638). It feeds on phytoplankton and on diatom sediment on the sand; the so-called 'multitooth' morph at Cape Maclear grazes from rocks and might harvest the loose aufwuchs (Ref. 5595). A maternal mouthbrooder; males defend territories from shallow water down to at least 28m; males dig pits, which are sometimes huge craters with a small raised platform of fine sand (Ref. 118638). It is an important component of the fisheries catch in Lake Malawi (Ref. 118638). The IUCN conservation status is rated as endangered, based on declining fishery catches due to overfishing (Ref. 118638).
A maternal mouthbrooder; males defend territories from shallow water down to at least 28m; males dig pits, which are sometimes huge craters with a small raised platform of fine sand (Ref. 118638). Breeding period extends over several months as noted in Lake Malombe, at present one of the main breeding areas for this species (Ref. 6150). Males build nests on a variety of substrata and at depths of 0.5m to at least 28m; nests generally 0.3-1.9m diameter, with dimensions correlated to male size (Ref. 55079). Nest with a characteristic spawning cone in its center (Ref. 5595). Courtship appears to occur mainly in the early morning (Ref. 40193, 55079), and consist of leading, followed by tilting and head-down quivering if the female follows the male to the nest (Ref. 40193). A female with 324 young of 15mm long in the mouth has been caught (Ref. 2781). Females keep guarding their fry until they are about 24 mm (Ref. 2781, 6150).
Trewavas, E. and G.G. Teugels, 1991. Oreochromis. p. 307-346. In J. Daget, J.-P. Gosse, G.G. Teugels and D.F.E. Thys van den Audenaerde (eds.) Checklist of the freshwater fishes of Africa (CLOFFA). ISNB, Brussels; MRAC, Tervuren; and ORSTOM, Paris. Vol. 4. (Ref. 5166)
IUCN Red List Status (Ref. 130435)
Threat to humans
Harmless
Human uses
Fisheries: commercial
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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=0.01259 (0.00716 - 0.02213), b=2.96 (2.82 - 3.10), in cm total length, based on LWR estimates for this species & Genus-body shape (Ref.
93245).
Trophic level (Ref.
69278): 2.0 ±0.00 se; based on food items.
Resilience (Ref.
120179): Medium, minimum population doubling time 1.4 - 4.4 years (K=0.24-0.56).
Fishing Vulnerability (Ref.
59153): Moderate vulnerability (38 of 100).
Nutrients (Ref.
124155): Calcium = 14 [6, 73] mg/100g; Iron = 1.21 [0.54, 2.88] mg/100g; Protein = 17.9 [16.2, 19.7] %; Omega3 = 0.387 [0.134, 1.079] g/100g; Selenium = 85 [31, 197] μg/100g; VitaminA = 19.7 [4.5, 81.8] μg/100g; Zinc = 2.06 [1.13, 4.89] mg/100g (wet weight);
