Country Species Summary

Heterotis niloticus in Central African Republic
Heterotis

Heterotis niloticus (Cuvier, 1829)
Family:	Arapaimidae (Bonytongues)	picture (Henil_u1.jpg) by Laleye, P.
Order:	Osteoglossiformes (bony tongues)
Class:	Actinopterygii (ray-finned fishes)
FishBase name:	Heterotis
Max. size:	100.0 cm SL (male/unsexed; Ref. 31256); max. published weight: 10.2 kg (Ref. 2920)
Environment:	pelagic ; depth range - 1 m
Climate:	tropical; 25 - 30°C; 18°N - 22°S
Global Importance:	fisheries: commercial; aquaculture: commercial; aquarium: commercial
Resilience:	Medium, minimum population doubling time 1.4 - 4.4 years (K=0.22-0.4)
Distribution:	Africa: Native in all the basins of the Sahelo-Sudanese region, the Senegal, Gambia, Corubal, Volta, Ouémé, Niger, Bénoue, Chad and Nile basins and Lake Turkana (Ref. 2920, Ref. 3012, Ref. 3514). Successful introductions in the storage reservoirs of Côte d'Ivoire, the Cross, Sanaga, Nyong and Ogowe rivers and lower and Middle Congo basin, including Ubangui and Kasaï (Ref. 2920). Also introduced in Madagascar (Ref. 13333). Several countries report adverse ecological impact after introduction.
Diagnosis:	Dorsal spines (total): 0-0; Dorsal soft rays (total): 32-37; Anal spines: 0-0; Anal soft rays: 34-39; Vertebrae: 66-69. Elongated and robust body, its height 3.5 to 5 times in standard length (Ref. 2920). Relatively short head, its length 3.5 to 5 times in standard length (Ref. 2920, Ref. 5156). Dermal bones of the cranium are deeply carved by large sensory pits (Ref. 1878, Ref. 2920). The lips are thick and there is a dermal flap on the border of the gill cover (Ref. 13851). Conical teeth (Ref. 5156). Dorsal and anal fins, which are spineless, elongated and posteriorly positioned, ending close to the small, rounded caudal fin (Ref. 3032, Ref. 13851, Ref. 28714, Ref. 30488). Caudal peduncle very short (Ref. 2756, Ref. 3054, Ref. 3069). Strong, large scales (Ref. 28714, Ref. 30488), oval with the exposed portion thick and corrugated, with a more or less vermiform sculpture (Ref. 53264): 34-40 lateral-line scales, 2.5/6 scales on the lateral side of the body before the pelvic fin, 5-6 scales between dorsal and anal fin (Ref. 367, Ref. 2756, Ref. 2920, Ref. 5156). The lateral line is extending in a straight line from above the operculum to the middle of the caudal peduncle (Ref. 1878). The number of gill rakers increases with the length; 33 (young) to 98 on the ceratobranchial and 21 (young) to 76 on the epibranchial (Ref. 2920). Young specimens possess external gills (Ref. 30488). Uniform gray, brown or bronze colored (Ref. 2920), darker during the reproduction-period (Ref. 367). Young specimens are often marked with dark longitudinal bands and scales with an oval spot in the posterior zone of the anal and dorsal fin (Ref. 2920).
Biology:	Maximum observed length in Lake Kainji: 100 cm, observed weight: 10000 g (Ref. 3034, Ref. 3799). Young found in swampy places among aquatic vegetation (Ref. 5156, Ref. 30488); adults live in the open water of rivers and lakes, where they can be found in the pelagic zone as well as the littoral zone (Ref. 5156). Its auxiliary branchial air breathing organs enable it to survive in deoxygenated waters; the hardiness of this fish, together with its great growth rate make it a candidate for aquaculture in Africa and it has been transported to a number of countries for this purpose (Ref. 1739, Ref. 50623). Escapees from ponds into the wild resulted in established populations, which form the basis for fisheries (Ref. 1739). This species is considered as a mud-feeder (Ref. 6160), but in West Africa also as a phytoplankton feeder (Ref. 3023, Ref. 31256). It feeds mostly on plankton, being the only plankton-feeder of the Osteoglossidae (Ref. 13851). It has a suprabranchial organ which has a sensory function, but also a mechanic function in concentrating the little food particles (Ref. 3012, Ref. 50624). During breeding, it creates a circular nest in swamps (Ref. 13851, Ref. 26281, Ref. 41544). The young leave the nest after a few days and are guarded by the male (Ref. 26281)
Threatened:	Not Evaluated, see IUCN Red List , (Ref. 36508)
Dangerous:	potential pest
Coordinator:
Main Ref:	Paugy, D.. 1990. (Ref. 2920)
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Central African Republic country information
Common names:	[ No common name ]	Ref:
Status:	introduced	Ref: Lever, C., 1996
Salinity:	freshwater
Aquaculture:	commercial	Ref: Welcomme, R.L., 1988
Uses:	no uses
Comments:	Introduced in Bangui for aquaculture and escaped and established in the Ubangui River (Ref. 331, Ref. 1978, Ref. 13364).
Country Information:	www.cia.gov/cia/publications/factbook/geos/ct.html
Occurrences:	Occurrences Point map
Main Ref:	Welcomme, R.L., 1988
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Checked: Casal, Christine Marie V.

Modified: Boden, Gert

Entered: Welcomme, Robin L.

CGNET - US

Page created by: Eli, 20.10.03, last modified by Eli, 26.06.07

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		(e.g. 9948)		(e.g. cephalopods)
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