Oreochromis mossambicus   (Peters,  1852) (Fish)
Organism information awaits expert curation
Taxonomy
Kingdom:Animalia
Phylum:Chordata
Class: Actinopterygii
Order:Perciformes
Family:Cichlidae

Image copyrights: JJPhoto

Description
Size: 35-39 cm TL.

Max. weight reported: 1,130 g.

Dorsal spines (total): 15 - 18; Dorsal soft rays (total): 10 - 13; Anal spines: 3; Anal soft rays: 7 - 12; Vertebrae: 28 - 31. Diagnosis: snout long; forehead with relatively large scales, starting with 2 scales between the eyes followed by 9 scales up to the dorsal fin. Adult males develop a pointed, duckbill-like snout due to enlarged jaws, often causing the upper profile to become concave, but upper profile convex in smaller specimens. Pharyngeal teeth very fine, the dentigerous area with narrow lobes, the blade in adults longer than dentigerous area; 28-31 vertebrae; 3 anal spines; 14-20 lower gill-rakers; genital papilla of males simple or with a shallow distal notch; caudal fin not densely scaled; female and non-breeding male silvery with 2-5 mid-lateral blotches and some of a more dorsal series; breeding male black with white lower parts of head and red margins to dorsal and caudal fins. Description: moderately deep-bodied, but very variable according to food availability. Head profile straight in juveniles and females. Mouth large. Lower jaw prominent; lips thick. Maxillary ending between nostril and eye in females and immature males, in breeding males mouth reaching to below anterior border of eye or a little beyond. Eye with yellow ring around pupil. Otoliths: sulcus with nearly straight crista inferior at the transition between ostium and cauda (thus no ventralward widening of the ostium is present). 2-3 series of scales on cheek. Scales cycloid. Scales on belly small, breast scales even smaller. Large scales on opercle, in 3 rows. 17-23 scales in upper part of lateral line, 10-17 in lower part. 9-12 predorsal scales. 15 precaudal vertebrae; 15-16 caudal vertebrae; 12-13 pairs of pleural ribs; 2 pairs of epineurals; 6 pairs of epipleurals; ventral vertebral apothysis on third vertebra. Gill-rakers short and thick. Dorsal fin spines subequal from the sixth; dorsal soft rays a little longer than longest spines. Last dorsal spine the longest. Soft part of dorsal and anal fin long and pointed, especially in males. Dorsal fin with 25-28 pterygiophores. Pectoral fin (nearly) as long as head, pointed, reaching to vent or to a little beyond origin of anal fin. 4-6 scales between bases of pectoral and pelvic fins. Anal fin with 11-12 pterygiophores. Outer rays of pelvic fins slightly produced, reaching to vent or beyond origin of anal. Caudal fin scaly in the basal half, the angles sometimes rounded. Central caudal fin skeleton with 3 epurals, 5 hypurals and 2 pairs of uroneurals. No genital tassel. Coloration: basic melanin pattern of 2 horizontal and 6-7 vertical bars never fully realized; more commonly, at least in preserved specimens, females and sexually inactive males have no bands, but may have the intersection points of the facultative bands represented by 3-4 upper and 2-5 mid-lateral blotches, or some or all of these may be present. Basic body coloration silvery grey to greenish grey, sometimes a more bluish colored head. Belly greyish. Spiny part of dorsal fin light with dark mottling. Soft dorsal and anal, and caudal and pelvic fins blackish. Pectoral fins colorless. Indistinct, dark opercular spot present. Vertical fins uniform, blackish with more or less distinct whitish spots or with large or small, fused or non-fused, dark spots on a pale background, given a darker aspect to these fins. 3 black blotches present in juveniles but possibly obscured in adults due to the dark body coloration of breeding males or old adults. Female and non-breeding male: dirty yellowish-olive or silvery-gray, with 2-5 mid-lateral blotches and some of a more dorsal series. Sometimes a series of more or less distinct spots along the side of the body above and below the upper lateral line. Breeding male: uniform dark olive-brown, deep blue-black or black, with white lower parts of head, including throat, lower lips, lower parts of cheeks and opercles, but with a dark blue to black base to the throat, and red margins to dorsal and caudal fins. Dorsal fin with light coloured spots on membrane between spinous and soft rays. Caudal fin olive-green with light coloured spots on anterior section, but may sometimes appear totally red. Tip of dorsal and extremity of caudal lobes yellowish. Anal fin dark gray or olive-green, sometimes with a thin red/orange margin. Unpaired fins normally exhibit greenish to silvery iridescent dots. Pectoral fin rays red. Pectoral and pelvic fins olive-yellow. Juveniles: body silvery or olive-brown, light on belly. Scales with dark outer edge. Usually 5-8 or more indistinct dark cross bars on body, often in addition to the 2 series of blackish spots, but with no horizontal stripes. Dark opercular spot, on posterior dorsal edge of operculum. Black spot at base of anterior rays of soft dorsal and 1-2 whitish spots enclosed by dark streaks. Oblique streaks or translucent round spots on soft dorsal. Anal dark at base with a light outer half, with oblique streaks. Caudal dark at base, light in centre, a black outer ridge, with 2-3 bars across the fin. Tilapia-spot present, conspicuous in younger fish persisting albeit faintly to 8cm. Fins flesh coloured, all except soft dorsal immaculate.

Polygamous, maternal mouthbrooder. Reaches sexual maturity at 15 centimeter length, but stunted fish may breed at 6-7 centimeters and at an age of just over 2 months. Fecundity high.

Somewhat aggressive toward other species.

Max age reported: 11 years.

Synonym (s)
Chromis dumerilii Steindachner, 1864
(junior synonym)
Chromis mossambicus Peters, 1852
(senior synonym)
Chromis natalensis Weber, 1897
(junior synonym)
Chromis niloticus (non Linnaeus, 1758)
(misapplied name)
Chromis niloticus var. mossambicus Peters, 1852
(senior synonym)
Chromis vorax Pfeffer, 1893
(junior synonym)
Cromis mossambicus Peters, 1852
(senior synonym)

Common Name (s)
• Mozambique tilapia (English)
Economic Importance and Threats
Importance:  Commercial
(Marketed fresh and frozen.)

Ecology
Habitat:  Estuarine, Muddy, Coastal
Prey:  Feeds mainly on algae and phytoplankton but also takes some zooplankton, small insects and their larvae, shrimps, earthworms and aquatic macrophytes. Large specimen has been reported to prey on small fishes, and occasionally cannibalise their own young. Exhibits considerable plasticity in its feeding habits.
IUCN Status:  NearThreatened

Biogeography


• Tamil Nadu, Muttukadu lagoon INDIA
• Kerala, Ayiramthengu INDIA

Literature Source(s)
  • Society for the Management of European Biodiversity Data (2009) World Register of Marine Species (WoRMS) Available at - http://www.marinespecies.org
  • Froese, R and Pauly, D (2000) Fishbase 2000: Concepts, design and data sources ICLARM 344 pp Available at - http://www.fishbase.org
  • (2003) IUCN Red list of threatened species Available at - http://www.iucnredlist.org/
  • Balasubramanian, T and Ajmal, SK(Eds by) (2004) Checklist of fish fauna of Ayiramthengu mangroves,Kollam district, Kerala, India Seshaiyana 12(2) Available at - http://www.casmbenvis.nic.in/pdf/Seshaiyana12-2.pdf

Page last updated on:2011-03-22

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