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Gymnarchus niloticus in Mauritania
Aba

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Gymnarchus niloticus   Cuvier, 1829
Family:	Gymnarchidae (Abas)			picture (Gynil_u0.jpg) by Moreau, J.
Order:	Osteoglossiformes  (bony tongues)
Class:	Actinopterygii (ray-finned fishes)
FishBase name:	Aba
Max. size:	167 cm SL (male/unsexed; Ref. 2915); max. published weight: 18.5 kg (Ref. 2915)
Environment:	demersal; potamodromous; pH range: 6.5 - 8; dH range: 10 - 25
Climate:	tropical; 23 - 28°C; 5°N - 18°N
Global Importance:	fisheries: commercial
Resilience:	Low, minimum population doubling time 4.5 - 14 years (K=0.12-0.17)
Distribution:	Africa: occurring widely in the Nile, Niger, Volta, Chad, Senegal and Gambia basins and Lake Rudolf.
Diagnosis:	Dorsal spines (total): 0-0; Dorsal soft rays (total): 183-230. Body depth 7.2-10.3 x SL. Head 5.6-6.9 x SL. Snout prominent. Pectorals 1.9-5.0 x head length. Body terminates in thin point. Head without scales. Scales small.
Biology:	Following flooding of the river banks (Gambia River), this species builds large elliptical floating nests in densely vegetated swamps at depths of about 1-1.5 m; lays about 1000 `amber-like' eggs; larvae hatching after 5 days (Ref. 10609). Feeds on crustaceans, insects and fish (Ref. 28714). No pelvic, anal or caudal fins. Possesses an electric organ that extends along almost the entire trunk to the tip of the tail (Ref. 10840). Also equipped with ampullary receptors and two types of tuberous receptors for electroreception (Ref. 10841). Showed increased electric organ discharge (EOD) rate by 50-60 Hz between 21 and 31°C (Ref. 10837)
Threatened:	Not Evaluated, see IUCN Red List  , (Ref. 36508)
Dangerous:	harmless
Coordinator:
Main Ref:	Bigorne, R.. 1990. (Ref. 2911)
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Mauritania country information
Common names:	[ No common name ]		Ref:
Status:	native		Ref:
Salinity:	freshwater, brackish
Importance:	commercial		Ref:  Mohamed Fall, K.O., 2005
Regulations:	no regulations		Ref:
Uses:	no uses
Country Information:	www.cia.gov/cia/publications/factbook/geos/mr.html
Occurrences:	Occurrences    Point map
Main Ref:	Mohamed Fall, K.O., 2005
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More information:	Countries FAO areas Occurrences Introductions Ecosystem Ecology Diet Food items Food consumption Ration Predators Ciguatera Fish loss Common names Synonyms Pictures Sounds Reproduction Maturity Spawning Eggs Egg dev. Larvae Larval dynamics References Growth L-W relationship L-L relationship Length frequencies Recruitment Max. age & size Metabolism Morphology Morphometrics Gill area Brains Vision Collaborators Genetics Allele frequencies Heritability Strains Aquaculture Aquaculture profile Diseases Ecotoxicology Processing Speed Swim. type Stamps
	Note: No data are available if label is black .
Tools:	Biogeographic modelling | Bio-Quiz | E-book | Field guide | Length-frequency Wizard | Life-history tool | Point map |
Internet sources:	BiOSC Point Data | CISTI | Google | GOBASE | GenBank ( genome, nucleotide ) | PubMed | Recipes | Scirus | Public aquariums | Tree of Life | Zoological Record Other web sites |
	Note: use the Back button of your browser to return to FishBase.
	Checked:  Mohamed Fall, K.O.	Modified:  Torres, Armi G.	Entered:  Torres, Armi G.

	Ref.:				Glossary
		(e.g. 9948)				(e.g. cephalopods)
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Page created by: Eli, 20.10.03, last modified by Eli, 26.06.07