African lungfish
Protopterus annectens
FAMILY
Protopteridae
TAXONOMY
Lepidosiren annectens Owen, 1839, Congo River. Two subspecies sometimes recognized.
OTHER COMMON NAMES
German: Afrikanischer Lungerfische; Afrikaans: Longvis.
PHYSICAL CHARACTERISTICS
Reaches 3.3 ft (1 m) in length. Separated from other Protopterus species by its relatively more slender head; 40–50 scales between operculum and anus, 36–40 scales around body anterior to dorsal fin origin; and 34–37 pairs of ribs. Olive to dark brown dorsally, lighter underneath, usually with spots and blotches on dorsal and lateral aspects.
DISTRIBUTION
Numerous rivers and lakes throughout central, South, and West Africa, e.g., the Senegal, Niger, Gambia, Volta, and Chad basins; the Chari River in Western Sudan; Bandama and Camoé basins in Côte d'Ivoire; Congo basin; the Zambezi and Incomati Rivers in South Africa. Also in Sierra Leone and Guinea, and the upper Nile basin.
HABITAT
Stagnant freshwater habitats, such as swamps and floodplains, also in more flowing rivers and streams.
BEHAVIOR
Estivation is well documented. Individuals will "chew out" a burrow 1.2–9.8 in (30–250 mm) deep, expelling mud through their gill openings. They eventually turn to rest facing the entrance, forming a bulb-shaped chamber that contains water in its lower portion. They periodically extend forward to breathe air from the opening, returning to rest in mucus secreted in the water-filled portion of the chamber. Their metabolic activity decreases progressively as the chamber becomes drier, and the chamber may eventually solidify into a hard cocoon. They may remain for up to seven or eight months in this resting state, until moist conditions return. This species is solitary and hyperdispersed in nature.
FEEDING ECOLOGY AND DIET
Feeds on insects, their larvae, other invertebrates, and fishes, also algae or aquatic plants. May masticate food items repeatedly, and even reported to spit out and intake prey repeatedly during feeding.
REPRODUCTIVE BIOLOGY
Males do not develop vascularized structures on their pelvic fins during breeding. Males usually guard larvae in nest sites that they dig out. Embryos hatch in one to two weeks, with conspicuous external gills, and will become obligate air breathers after about one month.
CONSERVATION STATUS
Not listed by the IUCN.
SIGNIFICANCE TO HUMANS
Kept in public aquaria, and consumed locally but not intensely. Not widely kept by amateur aquarists and does not figure prominently in the ornamental fish trade.
