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Gymnarchus niloticus  Cuvier, 1829

Aba
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Gymnarchus niloticus
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Senegal country information

Common names: Alluuxuune, Beesoo, Galakh
Occurrence: native
Salinity: freshwater
Abundance: | Ref:
Importance: | Ref:
Aquaculture: | Ref:
Regulations: | Ref:
Uses: no uses
Comments: Occurs in the Senegal River (Ref. 28587).
National Checklist:
Country Information: httpss://www.cia.gov/library/publications/resources/the-world-factbook/geos/sg.html
National Fisheries Authority: https://www.refer.sn/sngal_ct/eco/oeps/
Occurrences: Occurrences Point map
Main Ref: Adams-Sow, A. (ed.), 1996
National Database:

Classification / Names

Actinopterygii (ray-finned fishes) > Osteoglossiformes (Bony tongues) > Gymnarchidae (Abas)
Common names | Synonyms | Catalog of Fishes (gen., sp.) | ITIS | CoL

Common names from other countries

Main reference

Size / Weight / Age

Max length : 167 cm SL male/unsexed; (Ref. 2915); max. published weight: 18.5 kg (Ref. 2915)

Environment

Freshwater; demersal; pH range: 6.5 - 8.0; dH range: 10 - 25; potamodromous (Ref. 51243)

Climate / Range

Tropical; 23°C - 28°C (Ref. 13614), preferred ?; 18°N - 2°N, 16°W - 36°E

Distribution

Africa: occurring in the Gambia, Senegal, Niger, Volta and Chad River basins (Ref. 81275), Lake Turkana (Ref. 52331, 82489) and the Baro River drainage (Ref. 58460).
Countries | FAO areas | Ecosystems | Occurrences | Introductions

Short description

Dorsal spines (total): 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     Glossary (e.g. epibenthic)

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).

IUCN Red List Status (Ref. 115185)

Threat to humans

  Harmless



Human uses

Fisheries: commercial

More information

Common names
Synonyms
Metabolism
Predators
Ecotoxicology
Reproduction
Maturity
Spawning
Fecundity
Eggs
Egg development
Age/Size
Growth
Length-weight
Length-length
Length-frequencies
Morphometrics
Morphology
Larvae
Larval dynamics
Recruitment
Abundance
References
Aquaculture
Aquaculture profile
Strains
Genetics
Allele frequencies
Heritability
Diseases
Processing
Mass conversion
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Stamps, Coins
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Ciguatera
Speed
Swim. type
Gill area
Otoliths
Brains
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Tools

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Internet sources

Estimates of some properties based on models

Phylogenetic diversity index (Ref. 82805)
PD50 = 1.5000 many relatives (e.g. carps) 0.5 - 2.0 few relatives (e.g. lungfishes)

Trophic Level (Ref. 69278)
3.7   ±0.58 se; Based on food items.

Resilience (Ref. 69278)
Low, minimum population doubling time 4.5 - 14 years (K=0.12-0.17)

Vulnerability (Ref. 59153)
High to very high vulnerability (71 of 100)
Price category (Ref. 80766)
Unknown