Animal Diversity Web

Ge­o­graphic Range

North African cat­fish have been widely in­tro­duced around the world. They are found as far south as South Africa and north into north­ern Africa. They have also been in­tro­duced in Eu­rope, the Mid­dle East, and in parts of Asia. They are pota­mod­ro­mous, which means they mi­grate within streams and rivers (Teugels 1986). (Teugels, 1986)

• Biogeographic Regions
• palearctic
  • introduced
• oriental
  • introduced
• ethiopian
  • native

Habi­tat

North African cat­fish live in a va­ri­ety of fresh­wa­ter en­vi­ron­ments, in­clud­ing quiet wa­ters like lakes, ponds, and pools. They are also very promi­nent in flow­ing rivers, rapids, and around dams. They are very adap­tive to ex­treme en­vi­ron­men­tal con­di­tions and can live in pH range of 6.5-8.0. They are able to live in very tur­bid wa­ters and can tol­er­ate tem­per­a­tures of 8-35 de­grees Cel­sius. Their op­ti­mal tem­per­a­ture for growth is 28-30 de­grees Cel­sius (Teugels 1986).

They are bot­tom dwellers and do most of their feed­ing there. They are also ob­lig­ate air breathers, which means they do spend some time on the sur­face. This species can live in very poorly oxy­genated wa­ters and is one of the last species to live in such a un­in­hab­it­able place (Pien­aar 1968). They are also able to se­crete mucus to pre­vent dry­ing and is able to bur­row in the muddy sub­strate of a dry­ing body of water (Skel­ton 1993). (Pien­aar, 1968; Skel­ton, 1993; Teugels, 1986)

• Habitat Regions
• tropical
• freshwater

• Aquatic Biomes
• pelagic
• benthic
• lakes and ponds
• rivers and streams
• temporary pools
• brackish water

• Range depth

  4 to 80 m

  13.12 to 262.47 ft

Phys­i­cal De­scrip­tion

North African cat­fish are elon­gate with fairly long dor­sal and anal fins. The dor­sal fin has 61-80 soft rays and the anal fin has 45-65 soft rays. They have strong pec­toral fins with spines that are ser­rated on the outer side (Teugels 1986).

This species can at­tain sizes of up to 1.7 me­ters in­clud­ing the tail and can weigh up to 59 kg when fully grown. They posses nasal and max­i­al­lary bar­bels and some­what small­ish eyes. Their col­or­ing is dark grey or black dor­sally and cream col­ored ven­trally. Adults posses a dark lon­gi­tu­di­nal lines on ei­ther side of the head; how­ever, this is ab­sent in young fish. Adult's heads are coursely gran­u­lated, while the head is smooth in the young. The head is large, de­pressed, and heav­ily boned. The mouth is quite large and sub­ter­mi­nal (Skel­ton 1993). (Skel­ton, 1993; Teugels, 1986; Skel­ton, 1993; Teugels, 1986)

• Other Physical Features
• ectothermic
• bilateral symmetry

• Sexual Dimorphism
• male larger

De­vel­op­ment

North African cat­fish lay their eggs in veg­e­ta­tion. The eggs hatch within 25-40 hours. The lar­vae are able to swim and are able to feed within 2 or 3 days. Growth is very rapid, with males reach­ing an ul­ti­mately larger size than fe­males (Skel­ton 1993). (Skel­ton, 1993)

• Development - Life Cycle
• metamorphosis

Re­pro­duc­tion

This species par­tic­i­pates in mass spawn­ing.

• Mating System
• polygynandrous (promiscuous)

This species in known to breed in the sum­mers after the rainy sea­son. Vast num­bers mi­grate to "flooded shal­low grassy verges of rivers and lakes" (Skel­ton 1993). The eggs are laid in the veg­e­ta­tion. (Skel­ton, 1993)

• Key Reproductive Features
• seasonal breeding
• sexual
• fertilization
  • external

• Breeding season

  Summer

• Average time to hatching

  25-40 hours

Fur­ther re­search should be done on the amount of parental care given in this species.

• Parental Investment
• no parental involvement

Lifes­pan/Longevity

North African cat­fish live 8 or more years (Skel­ton 1993). (Skel­ton, 1993)

• Range lifespan
  Status: wild

  8 (low) years

Be­hav­ior

North African cat­fish are rel­a­tively poor swim­mers that spends most of the time on the bot­tom of lakes and rivers (Pien­aar 1968). They are, how­ever, able to move across land to an­other water source dur­ing damp con­di­tions (Skel­ton 1993). They sim­ply ex­tend their strong pec­toral fins and spines and begin crawl­ing through shal­low path­ways.

This species has been known, dur­ing in­tra-spe­cific ag­gres­sive in­ter­ac­tions, to emit an elec­tric organ dis­charge that was head-pos­i­tive and last­ing 5-260 mil­lisec­onds (Teugels 1986). (Pien­aar, 1968; Skel­ton, 1993; Teugels, 1986)

• Key Behaviors
• natatorial
• motile

Com­mu­ni­ca­tion and Per­cep­tion

It is not known whether this species in par­tic­u­lar uses its pec­toral spine to make sounds, but in other species of cat­fish this is very com­mon be­hav­ior. This species has also been know to gen­er­ate elec­tic organ dis­charges, but it is not known if this be­hav­ior is com­mu­nica­tive (Teugels 1986). (Teugels, 1986)

• Communication Channels
• acoustic
• electric

• Perception Channels
• visual
• tactile
• acoustic
• chemical

Food Habits

North African cat­fish are om­ni­vores. They are not spe­cific in their food re­quire­ments. They are known to feed on in­sects, plank­ton, snails, crabs, shrimp, and other in­ver­te­brates. They are also ca­pa­ble of eat­ing dead an­i­mals, birds, rep­tiles, am­phib­ians, small mam­mals, other fishes, eggs, and plant mat­ter such as fruit and seeds. Be­cause they are mo­bile on land, they are able to prey on ter­res­trial or­gan­isms. This species may also hunt in packs on oc­ca­sion by herd­ing and trap­ping smaller fish. They are also ref­ered to as sharp­tooth cat­fish be­cause of fine, pointed bands of teeth (Skel­ton 1993). (Skel­ton, 1993)

• Primary Diet
• omnivore

• Animal Foods
• birds
• mammals
• amphibians
• reptiles
• fish
• eggs
• carrion
• insects
• terrestrial non-insect arthropods
• mollusks
• aquatic crustaceans
• other marine invertebrates
• zooplankton

• Plant Foods
• seeds, grains, and nuts
• fruit

Pre­da­tion

Be­cause of the abun­dance of this species and its lack of mo­bil­ity on land and in water, it is preyed upon widely. Man is the pri­mary preda­tor, but oth­ers in­clude leop­ards, croc­o­diles, and birds. The fish eagle and marabou stork are very com­mon preda­tors (Skel­ton 1993) (Skel­ton, 1993)

• Known Predators

  • leopards (Panthera pardus)
  • humans (Homo sapiens)
  • crocodiles (Crocodylus)
  • birds (Aves)
  • fish eagles (Haliaeetus)
  • marabou storks (Leptoptilos crumeniferus)

Ecosys­tem Roles

North African cat­fish are an im­por­tant player in cer­tain ecosys­tems. In Thai­land, they have been in­tro­duced as a farm fish. How­ever, in these marshes and swamps where they are raised, there is a na­tive cat­fish, walk­ing cat­fish, that is near­ing ex­tinc­tion. This is due to the pop­u­la­tion ex­pan­sion of the the North African cat­fish. It is also due to the back-cross­ing of the walk­ing cat­fish and the hy­brid of the two species. This is also re­duc­ing the ge­netic vari­a­tion of the na­tive walk­ing cat­fish (Na-Nakorn et al 2004). This species is also im­por­tant in nu­tri­ent re­cy­cling in con­juc­tion with rice fields. The trans­fer of nu­tirents takes place from the pond to the rice via fish feces, which in­creases rice yields (d'Oul­tremont and Gutier­rez, 2002). (d'Oul­tremont and Gutier­rez, 2002; Na-Nakorn, et al., 2004)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

North African cat­fish are a very good food source for hu­mans. They are farmed ex­ten­sively all over Asia. Be­cause of this, this species and other farmed cat­fish are in­volved with ex­ten­sive diet ex­per­i­ments. These ex­periements are meant to find the best diet for op­ti­mal yield. One such study is at­tempt­ing to find the op­ti­mal di­etary car­bo­hy­drate to lipid ratio in the fish's diet (Ali and Jauncey, 2004). An­other sim­i­lar study is test­ing the di­gestibil­ity of oilseed cakes and meals for use in the fish's diet (Fag­benro, 1998). There are many other stud­ies that are test­ing sim­i­lar ideas about the African cat­fish's diet to im­prove the suc­cess of the farms. (Ali and Jauncey, 2004; Fag­benro, 1998)

• Positive Impacts
• food

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Be­cause north African cat­fish are heav­ily farmed around the world, there are some ad­verse ef­fects on na­tive pop­u­la­tions of fishes. North African cat­fish breed with na­tive walk­ing cat­fish, which pro­duce some steril­ity when back cross­ing oc­curs (Na-Nakorn et al, 2004). An­other ad­verse ef­fect of fish farm­ing in gen­eral is the ef­fect of fish farm waste on the sur­round­ing ecosys­tem. There are large amounts of feed and fecal mat­ter near fish farms. This waste is fur­ther spread by wild fish and de­posited an even fur­ther dis­tance from the farm. This kind of dis­per­sal has great ef­fects on the en­vi­ron­ment. It af­fects the feed­ing be­hav­ior and per­for­mance of other aquatic an­i­mals, in­clud­ing other fishes, crus­taceans, and mus­sels (Sara et al., 2004). (Na-Nakorn, et al., 2004; Sara, et al., 2004)

Con­ser­va­tion Sta­tus

• IUCN Red List

  Data Deficient

• US Federal List

  No special status

• CITES

  No special status

Con­trib­u­tors

Hal Gun­der (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor, William Fink (ed­i­tor, in­struc­tor), Uni­ver­sity of Michi­gan-Ann Arbor, Matthew Wund (ed­i­tor), Uni­ver­sity of Michi­gan-Ann Arbor.

Ref­er­ences

Ali, M., K. Jauncey. 2004. Op­ti­mal di­etary car­bo­hy­drate to lipid ratio in African cat­fish Clar­ias gariepi­nus (Burchell 1822). Aqua­cul­ture In­ter­na­tional, 12: 169-180.

Fag­benro, O. 1998. Short com­mu­ni­ca­tion ap­par­ent di­gestibil­ity of var­i­ous oilseed cakes/meals in African cat­fish diets. Aqua­cul­ture In­ter­na­tional, 6: 317-322.

Na-Nakorn, U., W. Ka­mon­rat, T. Ngam­siri. 2004. Ge­netic di­ver­sity of walk­ing cat­fish, Clar­ias macro­cephalus, in Thai­land and ev­i­dence of ge­netic in­tro­gres­sion from farmed C. gariepi­nus . Aqua­cul­ture, 240: 145-163.

Pien­aar, U. 1968. The Fresh­wa­ter Fishes of the Kruger Na­tional Park. Re­pub­lic of South Africa: The Na­tional Parks Board of Trustees of the Re­pub­lic of South Africa.

Sara, G., D. Scilipoti, A. Maz­zola, A. Mod­ica. 2004. Ef­fects of fish farm­ing waste to sed­i­men­tary and par­tic­u­late or­ganic mat­ter in a south­ern Mediter­ranean area (Gulf of Castel­lam­mare, Sicily): a mul­ti­ple sta­ble iso­tope study. Aqua­cul­ture, 234: 199-213.

Skel­ton, P. 1993. A Com­plete Guide to the Fresh­wa­ter Fishes of South­ern Africa. Halfway House: South­ern Book Pub­lish­ers Ltd..

Teugels, G. 1986. A sys­tem­atic re­vi­sion of the African species of the genus Clar­ias (Pisces: Clari­idae).. An­nales Musee Royal de l'Afrique Cen­trale, 247: 1-199.

d'Oul­tremont, T., A. Gutier­rez. 2002. A mul­ti­trophic model of a rice-fish agroe­cosys­tem: II. Link­ing the flooded rice-fish­pond sys­tem. Eco­log­i­cal Mod­el­ling, 155: 159-176.