Nigeria country information

Common names: Aba, Asa, Dan sarki
Occurrence: native
Salinity: freshwater
Abundance: | Ref:
Importance: commercial | Ref: Anonymous, 1998
Aquaculture: | Ref:
Regulations: | Ref:
Uses: no uses
Comments: Occurs in the Ogun River (Ref. 13331) and Ehoma Floodplain, Afikpo (Ref. 52861). Exploited commercially in Kainji Lake (Ref. 28265). Also Ref. 31256.
National Checklist:
Country Information: https://www.cia.gov/library/publications/resources/the-world-factbook/geos/ni.html
National Fisheries Authority:
Occurrences: Occurrences Point map
Main Ref: Ita, E.O., 1984
National Database:

Common names from other countries

Aba aba, Frankfish, Yor, ... more

Classification / Names Common names | Synonyms | Catalog of Fishes(genus, species) | ITIS | CoL | WoRMS | Cloffa

Teleostei (teleosts) > Osteoglossiformes (Bony tongues) > Gymnarchidae (Abas)
Etymology: Gymnarchus: Greek, gymnos = naked + Greek, archos = anus (Ref. 45335).
More on author: Cuvier.

Environment: milieu / climate zone / depth range / distribution range Ecology

Freshwater; demersal; pH range: 6.5 - 8.0; dH range: 10 - 25; potamodromous (Ref. 51243). Tropical; 23°C - 28°C (Ref. 13614); 18°N - 2°N, 16°W - 36°E

Distribution Countries | FAO areas | Ecosystems | Occurrences | Point map | Introductions | Faunafri

Africa: basins of the rivers Senegal, Gambia, Volta, Niger and Chad in West Africa (Ref. 3530, 81275). Also in the Nile River basin (Ref. 3530, 28714) and Lake Turkana (Ref. 3530, 52331).

Size / Weight / Age

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

Short description Morphology | Morphometrics

Dorsal spines (total): 0; Dorsal soft rays (total): 183-230. Diagnosis: body very elongate (Ref. 28714, 81275), anguilliform (Ref. 81275), its depth 7.2-10.6 times in SL, and covered with tiny scales (Ref. 2915, 81275). Lateral line complete (Ref. 81275). Dorsal fin soft-rayed, extending almost over the entire length of back (Ref. 81275), stopping short of a naked tail (Ref. 28714). Pelvic, anal and caudal fins absent (Ref. 28714, 81275), body ending in a thin/sharp point (Ref. 2915, 81275). Pectoral fins reduced (Ref. 81275), 1.9-5.0 times in head length (Ref. 2915, 81275). Head naked, its length 5.6-6.9 times in SL; snout prominent (Ref. 2915, 81275). Mouth large and terminal; teeth strong, pointed or notched, aligned in a single row in both jaws, 12-16 in upper, 22-28 in lower jaw; premaxillae, as well as vomer and palatines, coalesced; maxillae, vomer and palatines toothless; eye very small, without a free margin (covered by skin); only the left gonad is developed and functional (Ref. 81275). Coloration: dark grey to almost black, darker posteriorly; belly whitish (Ref. 81275).

Obligate air-breathing (Ref. 126274); Obligate air-breathing (Ref. 118411, 126274). Inhabits marginal vegetation and swamps constructing a flask-shaped nest in vegetation during the floods, which it is reputed to defend with vigour (Ref. 28714). Following flooding of the Gambia River banks, large elliptical floating nests are build in densely vegetated swamps at depths of about 1-1.5 m, in which about 1000 ‘amber-like’ eggs are laid; larvae hatch after 5 days (Ref. 10609). Feeds on crustaceans, insects and fish (Ref. 28714). No pelvic, anal or caudal fins (Ref. 28714). 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).

Life cycle and mating behavior Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae

Breeds in well-vegetated, marginal areas of swamps and rivers, where a large, floating nest, about 1 m in diameter, is constructed, in which the eggs are laid and later guarded by one of the parents (Ref. 27583). Distinct pairing (Ref. 205).

Main reference Upload your references | References | Coordinator | Collaborators

Bigorne, R., 1990. Gymnarchidae. p. 185-186. In C. Lévêque, D. Paugy and G.G. Teugels (eds.) Faune des poissons d'eaux et saumâtres d'Afrique de l'Ouest. tome 1. Faune Trop. 28. Musée Royal de l'Afrique Centrale, Tervuren, Belgique and ORSTOM, Paris. (Ref. 2911)

IUCN Red List Status (Ref. 130435)

Least Concern (LC) ; Date assessed: 12 May 2019

CITES (Ref. 128078)

Not Evaluated

CMS (Ref. 116361)

Not Evaluated

Threat to humans

Harmless

Human uses

Fisheries: commercial

FAO(Aquaculture: production; Fisheries: production; publication : search) | FishSource |

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Estimates based on models

Phylogenetic diversity index (Ref. 82804): PD₅₀ = 1.5000 [Uniqueness, from 0.5 = low to 2.0 = high].

Bayesian length-weight: a=0.00437 (0.00170 - 0.01121), b=3.08 (2.85 - 3.31), in cm Total Length, based on LWR estimates for this (Sub)family-body shape (Ref. 93245).

Trophic level (Ref. 69278): 3.7 ±0.58 se; based on food items.

Resilience (Ref. 120179): Low, minimum population doubling time 4.5 - 14 years (K=0.12-0.17).

Fishing Vulnerability (Ref. 59153): High vulnerability (63 of 100).

Price category (Ref. 80766): Unknown.

Gymnarchus niloticus Cuvier, 1829