Environment: milieu / climate zone / depth range / distribution range
Ecologia
; acqua dolce demersale; pH range: 6.5 - 8.0; dH range: 10 - 25; potamodromo (Ref. 51243). Tropical; 23°C - 28°C (Ref. 13614); 18°N - 2°N, 16°W - 36°E
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 / Peso / Age
Maturity: Lm ? range ? - ? cm
Max length : 167 cm SL maschio/sesso non determinato; (Ref. 2915); peso massimo pubblicato: 18.5 kg (Ref. 2915)
Short description
Chiavi di identificazione | Morfologia | Morfometria
Spine dorsali (totale) : 0; Raggi dorsali molli (totale) : 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
Maturities | Riproduzione | Spawnings | Egg(s) | Fecundities | Larve
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).
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)
Threat to humans
Harmless
Human uses
Pesca: commerciale
Strumenti
Special reports
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Estimates based on models
Phylogenetic diversity index (Ref.
82804): PD
50 = 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.
Generation time: 6.5 ( na - na) years. Estimated as median ln(3)/K based on 1
growth studies.
Resilienza (Ref.
120179): Basso, tempo minimo di raddoppiamento della popolazione 4.5 - 14 anni (K=0.12-0.17).
Fishing Vulnerability (Ref.
59153): High vulnerability (63 of 100).
Nutrients (Ref.
124155): Calcium = 62.6 [33.3, 136.7] mg/100g; Iron = 1.01 [0.56, 2.07] mg/100g; Protein = 17.4 [15.5, 19.1] %; Omega3 = 0.27 [0.11, 0.68] g/100g; Selenium = 118 [43, 271] μg/100g; VitaminA = 17 [6, 45] μg/100g; Zinc = 1.05 [0.73, 1.57] mg/100g (wet weight);
