Mormyrops anguilloides (Linnaeus, 1758)
Cornish jack
photo by de Vos, L.

Family:  Mormyridae (Elephantfishes)
Max. size:  150 cm TL (male/unsexed); max.weight: 15 kg
Environment:  demersal, potamodromous
Distribution:  Africa: a very wide distribution area which includes most of the West African river basins (Ref. 81274), White Nile River (Ref. 3203), Uebi Shebeli and Juba River (Ref. 3203), and the Congo River basin (Ref. 52193); in southern Africa, restricted to the middle and lower Zambezi, Buzi and Pungwe (Ref. 52193). Also known from Lake Malawi, Lake Tanganyika and Lake Albert [former Lake Mobuto] (Ref. 3203, 52193).
Diagnosis:  Dorsal spines (total): -0; Dorsal soft rays (total): 21-33; Anal spines: -0; Anal soft rays: 38-51. Diagnosis: head depressed, mouth large and terminal; body elongated (Ref. 13337, 52193). Chin (mental swelling) absent; origin of dorsal fin behind origin of anal fin, nearer caudal fin base than tip of snout; dorsal fin shorter than anal fin; mouth width subequal to snout length: snout long (Ref. 52193). SL/Body depth 4.9-7.5; head 3.4-5.1 times in standard length; snout almost as wide as head; interorbital space wide, head length/interorbital space 2.9-6.8; variation in meristic characteristics due to differences in geographic clines (Ref. 2915). Description: scales small; head and body elongated; median fins set well back; caudal fin relatively small, forked with rounded lobes; head smooth and depressed in front; mouth terminal with small pointed teeth in a single row; eyes small; gill slit restricted to sides, inclined at an angle (Ref. 52193). Coloration: grey above, lighter silvery white below, often with a bronze or yellow sheen; juveniles darker, greyish blue or brown (Ref. 52193).
Biology:  Juveniles occur in marginal habitats, adults prefer deep quiet water between boulders and below overhangs, away from strong currents; also occurs beneath Salvinia mats and in river estuaries in Lake Kariba; juveniles prey on invertebrates, mainly shrimps and insect larvae; larger individuals feed on small cichlids, minnows and labeos; may live for 8 years or more; breeds in summer during the rainy season; mature females carry 25000 or more eggs (Ref. 7248, 52193). A fractional spawner (Ref. 10606, 10605). Affinities: M. breviceps.
IUCN Red List Status: Least Concern (LC); Date assessed: 20 June 2018 Ref. (123251)
Threat to humans:  harmless
Country info:   

Entered by: Binohlan, Crispina B. - 04.03.91
Modified by: Reyes, Rodolfo B. - 27.02.14
Checked by: Casal, Christine Marie V. - 23.06.05

Source and more info: For personal, classroom, and other internal use only. Not for publication.

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