Sharptooth catfish
Clarias gariepinus
FAMILY
Clariidae
TAXONOMY
Silurus (Heterobranchus) gariepinus Burchell, 1822, Smidtsdrift, Vaal River, Cape Province, South Africa.
OTHER COMMON NAMES
English: Mubondo, North African catfish, Zambezi barbel; Spanish: Bagre dientón.
PHYSICAL CHARACTERISTICS
Length 5.6 ft (1.7 m); weight 132 lb (60 kg). Body naked and elongate; dorsal fin base very long, with 61–80 rays, not preceded by a spine, not continuous with caudal fin; adipose fin absent; pectoral fin spine serrated only on its external border; anal fin long, separated from caudal fin; caudal fin rounded; head depressed, covered with rugose bony plates; mouth terminal and transverse; four pairs of barbels; eyes superior, relatively small, and with a free orbital rim; gill openings wide; air-breathing labyrinthic organ arising from second, third, and fourth gill arches. Coloration countershaded, dark gray dorsally, milky white ventrally, ventral surface of head in adults with a black longitudinal band in each side; band absent in juveniles.
DISTRIBUTION
Africa in Niger and Nile River basins; also the Limpopo, Orange-Vaal, Okavango, and Cunene Rivers, South Africa, and in the Middle East, including Israel, Jordan, Lebanon, and Syria.
HABITAT
Benthopelagic in fresh waters and upper estuaries 13–262 ft (4–80 m) deep, but more common in shallow environments.
BEHAVIOR
Widely resistant to challenging environmental conditions; the accessory labyrinthic organ allows clariid catfishes to breathe air under dry conditions. Favors shallow marginal areas, but may appear in the open; nocturnal. Capable of walking through dry land using tough pectoral fin spines. May also discharge electricity during intraspecific agonistic behavior.
FEEDING ECOLOGY AND DIET
Omnivorous bottom feeder, feeds on insects, fishes, crustaceans, mollusks, plankton, fruits, plants, small birds, and carrion. Occasionally feeds at the surface.
REPRODUCTIVE BIOLOGY
Migrates upstream or to lakeshores in large numbers to spawn immediately after the first heavy showers of the rainy season. Sexually dimorphic, both males and females have elongated sexual organs, but male organ has cone-shaped tip. Spawning is nocturnal in shallow waters; eggs, which have an adhesive disk and are less than 0.10 in (0.25 cm) long, are not protected. Eggs hatch in one or two days. Juveniles stay in shallow, protected waters for about six months, migrating downstream before their nursery area dries up.
CONSERVATION STATUS
Not listed by the IUCN.
SIGNIFICANCE TO HUMANS
Although of relatively minor importance for fisheries, this is a valuable aquaculture species, due to its hardiness, rapid growth, ease of feeding and handling, and flesh quality. Also considered a game fish. Widely introduced to almost all Africa, and to some European, Asian, and South American countries; negative ecological impact has been reported. Trade restricted in Germany.
