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Home , Ariidae, Bagridae, Claroteidae, Gonorynchiformes, Heterobranchus, Heterobranchus isopterus

Biodiversity and aquaculture ofAfrican (Teleostei, Siluroidei): an overview

Guy G. Teugels lchthyologist Germain Gourène lchthyologist

Catfishes are a large group ofpredominantly freshwater fishes. TEUGELS (1996) listed 33 fandies, with 416 generaand 2484 . The systematics of catfishes however, are far from being completely known. Especially in and in South-East , several new species and evennew genera are regularly being discovered. Therefore total taxa numbers continuously change. The mostrecent estimates include 32 fandies, 4i8 generaand 2612 species. Catfishes belong to the Siluriformes, one of the four orders of the (Fm and Fm, 1981) includingalso Gonorynchiformes (ndkfkhes, etc.), (, suckers, etc.) andCharaciformes (piranhas, etc). Ostariophysi are recognized in particular by a notable modification of the anterior four or five vertebrae (three in Gonorynchiformes) into the so-called ,a conkection of alternating ligaments and smallbones between the gas bladderand the oticcapsule (CHARDON, 1968). It has an important role in sound perception and its developmentin Ostariophysi is undoubtedy related to their almost exclusive occurrence iniï-eshwater, where ofien limited visibility reduees Wsud perception. Within the Siluriformes, caffishes belongto the suborder Siluroidei. FI" and FNC (1981) md ARRATIA (1992) listeel several synapmorphies to demonstrate the monophyly of this group most of them based on osteological features. pin important variation exists in the externd nmphology of eatfishes and it is therefore di-ffieultto give a standard definition. General charaeters include the absence of seales (although in some South herican families the body is csvered with bony scutes), md the presence of up to four pairs 0.F ciremoral barbels, used for the deteetion of food. Dorsal and pectoral fins are oftenprovided with a leading spine. An adipose fin is often present. Catfishes occur in North, Central and South herica, Afiiea, Eurasia, South-East Asia, Japan andAustrallia. TEUeELs (1996) reprted on the proportional distribution of fieshwater catlishes in the world: some 64% of all speeies known are confned to Central and South Ameriea about 19% occur in Afhca and about 15% are found in Eurasia and South- East Asia. Sotne 2% of the speies are present in North hemca.

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Nearly one fifth of al1 known species occur in Afr-ica. Ten families are recognized. Two of them, kidae and Plotosidae, generally contain marine species and have a largediskibution. 'heeothers, Clariidae, Bagielae and Sehilbeidae, are also present in southern Asia. Al1 the others are endemic to Ajîica. At present 58 genera including 465 spcies are known. G. G. Teugelsand G. Gourène - Biodiversityand aquaculture of African Catfish v 231

Family Clariidae

This fandy occurs in Minor, South and South-East Asia and in Afi-ica. Its lughest diversity however is found in the latter continent. TEUGELS (1986a) reported 12 genera with 74 species in Afi-ica, while only 2 genera with some 17 species are presently known fiom Asia (TEUGELS,1996). Clariidae are elongated catfishes with long dorsal and anal fins. A dorsal spine is missing but the pectorals are provided with a strong leadingspine. An adipose fin is present in a fewgenera (e.g. ). They have four pairs of barbels. A remarkable character for this fatnily is the presence of a suprabranchial organ, formed by folds of the second and the fourth branchial arches. With this organ, the fishes are ableto practice aerial respiration, implicating that they can survive out of the water for a long time. They are also known for walhng on land over distances of several hundred meters, breathing atmospheric air and using their pectoral spines as a support. Within the Clariidae, the Clarim is the most speciose group, containing 32 species(TEUGELS, 1986b) inAfi-ica and some 12 speciesin Asia (TEUGELS, 1996). This genus contains the most cultured Afiican catfish (Figure l), CIarim gariepinus (Burchell, 1822). Its culture started almost fi@ years ago. Its large size (up to 1,5 m), its omnivorous feeding habits, its almost Panafîican distribution and its capacity to survive in poorly oxygenated water, favoureditsselection for aquaculturepurposes. For 1994, GARIBALDI(1996) reported a production of 3,978 metric tons in ffica and 1,057 mt in Europe. The species has alsobeen introduced in South-East Asia, where it is a severe threat for the local fish fauna. CIarim angdlaris (Linnaeus, 1758) is ofminor importance in Afiicanfishculture. GARIBALDI (1996) reporteda production of 1,185 mt in Afiicafor 1994. The species only occurs in West Afiica and the Nile. Although other CIarim species have been studied for aquaculture purposes,their importance is at present limited. Recently however the genus Heterobranchm, recognized by the presence of a large adipose fin and includingfour species (TEUGELS et al.. 1990), was introducedm aquaculture andshows most promising results. LEGENDREet al. (1999) demonstrated that under identical conditions, Heterobrmnchzls lonpilix Valenciennes; 1846 has a growth rate which doubles that of gariepinm. At present, H. lorzgi4ilis is cultured in @;te d'Ivoire (AGNESE et al.,

1995 )? Nigeria (NWADUKWE,1993), Canleroon (NGWNGAet al.> 1996) and Zmbia (HECHT el' al: 1991j. Heterobranchm isoptenls Bleeker, 1863 is another species presently cultured in C6te d'Ivoire (DA COSTAet al., 1996). Expriments with H. bidorsalis (Geo€fi-oy Saint-Hilaire, 1SOS> have recently been conducted in C6te d'Ivoire (Gilles. pers. conun.) and in Nigeria (FAGBENROet al.? 1993). Data on production offleterobranchusspecies are not yet available.

Figure '1 ; representative of the Clariidae.

Bathvclarias ( sometimes referrred to as Dinotopterus) is another clariid genus which isaet~~ally being sludied for aquaculture purposes in Malawi (Kaunda and Hecht, pers. eo~mn.).Pre1iminzu-y researeh byMSISKA et al. (1991 showed promisingresults. The genus merely differs fronlthe large CIarim and Heterobrmchus by the presence of a sn~alladipose fin and by the lswer jaw reaching beyond the upper jaw. The genus has alinlited distribution: a species-flock (12 speciesj has been described from Lake Malawi, one species is known from and another, originally described in Hetembranchlu, is known from Lake Mweru and its G. G. Teugels and G. Gourène - Biodiversityand aquacukure of African Calfish v233

neighbouring rivers (TEUGELS, in prep.), in between Lakes Malawi and Tanganyika. Their , growth, reproduction and feed requirements are presently being studied. Finally some anguilliform clariid genera are presently being tested on their aquaculture potential.Although belonging to the same family, they substantially differ fiom other clariidgenera. The body is extremely elongated and the head is strongly reduced. Several genera have been described but their taxonomy is problematic. In Belgium and the Netherlands experimental research is presently being done on Gyntnallabes typw Günther, 1867 as a possible replacement for common -culture.

Family

A detailed osteological and phylogenetical study led MO (1991) to Split the Bagridae into three families: Bagridae, Claroteidaeand Austroglanididae. As a result of MO'Srevision the Bagridae are represented in Mca by only one genus, Bagms containing 10 species. The genus is recognized by a nloderately elongated body,compressed posteriorly, four pairs of barbels, strong dorsal and pectoral spines and a large adipose fin. The genus has a large distribution including the Senegal, Niger, Volta, Chad and Nile basins, the East African Rift Lakes and the Zaire basin. Some species like Bugrta docntak (Forsskall, 1775) canattain a totallength of over one meter. Althoughthey are important food fishes, in those areas where they form an important part of the fish catches, they are presently notused in aquaculture.

Family

Following MO (1991) thisfamily contains 13 genera,all endemic to Mca. TEUGELS (1996) mentioned 88 species. Two subfamilies are recognized, Claroteinae andAuchenoglanidinae. The former includes seven genera, the latter hasfive. The most important 234 aquacultureGenefics and in Mica

difference between both sub-fal~siliesis thepresence of an aceessory tosthplate on the palate in the Claroteinae. The externalrnorphology varies considerably %?rithinthe f&ily. Generally, the body is moderately elongated. There are usually four pairs of barbels (three in ). Thedorsal and the pectoral fins have strong leadingspines and an adipose fim is present. Claroteidae have a large sub-sahariandistribution. Within the Claroteinae CIarotes and particulas-in C'hwsichthys are econsmicallyimportant. The latter kas been introduced in aquaculturein the early 1980's (HEM, 1986; DIA and OTEME, 1986). Chtysichthys nigrodigitatta (Lacepbde, 1803) (Figure 2) is presently cultured in Côte d'Ivoire (OUATTARAet al., 1993) and in Nigeria @MM,1993). For 1994, G~RIBALDI(1996) rnentioned a production of 1,503 rnt in Afi-ica. Witkin the Auchenoglanidinae,especially Atlehenoglmis is eeono~nicallyimportant inlocal catches. BARDACHet al. (1972), MCHA(1 973) and PLANQUETTE (1976) published on the aquaculture potential of Auchenoglmis occidentalis (Valenciennes, 1840). The species, however, is at presentnot used in aquaculture.

1 Figure 2 Chiysichthys nigrodigitatus, representative of the Claroteidae. G. G. Teugelsand G. Gourene - Biodiversityand aquacuiture of AfricanCatfish v235

Family Austroglanididae

Originallyincluded in the Bagridae,this family, containing one genus Amtroglanis with threespecies is only known from the Orange and Olifantsriverin southern . Morphologically, the fatnily is recognized by the presence of three pairs of barbels, strong dorsaland pectoral spines and a small, posteriorlyplaced adipose fin. The tnaxitnal size reported is 250 11m1. They have no importance in aquaculture.

Family Malapteruridae

The electriccaffish fatnily Malapteruridae contains one genus Malapter-urzLs. Three species are currently recognized as valid but the systematics of this group are poorly know~and are presently being revised (Norris, in prep.). Morphologcallythey arerecoguzed bya somewhat cylindrical body, three pairs of barbels, the absence of a dorsal fin and the absence of spines in the pectoral fin. -411 adipose finis present. They possess an electricorgan of tnuscular ohgin which produces violent electric discharges up to450 Volts. Electric caffishes have a wide distribution in tropical Africa. Their maxitqal total length is 1,5 m. They have no aquaculture potential.

Family Mochokidae

Eleven genera, including 177 species are presently known for this family, wluch is endemic to ffica. Theirexternal tnorphology consists in arobust body, slightly compressed posteriorly. They have three pairs of barbels, of which the mandibular pair is branched in sonle genera (e.g.Synodontis). The dorsal and pectoral fins have strong spines. An adipose fin is present.Although the tnaxilnallength reported is 800 mm in a species of ,S’vnodoontis,the mo~chokidsare ingeneral much smaller. They have not been introduced in aquaculture but some species are ppular aquarium fishes.

Amphlliids are small fi-eshwater caffishes (n~aximaltotal length 195 mm but usually much smaller) endemic to tropical fiea. Nine genera including 60 species are known. They have three pairs of barbels; in most genera dorsal and anal spines are lacking; an adipose fin is present. Many genera are rheophlic and display great~yenlarged peitoral and pd~cfim. hphiliidae are of no interest to aquaculture.

Schilbeidae are plagie catfishes found in freshwaters of Afiica and southern Asia. In A&ica DE VOS (1 995) recogrPized five genera with 34 species. Morphslogically schilbeid caffishes are recognized by a laterally compressecl body and two to four pairs of barbels. A short dorsal fin may be present or absent. Men present, it kas a strong spine. An adipose fin is present or absent. The anal fin is very long md the pectoral fin has a strong spine. Maximaltotal length reported is 590 mm in Schilbe. Some schilbeids are excellent and importantfood fish. No records on their introduction inaquaculture could be found.

Most ariids are marine caffishes with a worldwide distribution in tropical and subtropical regions. Four genera, Anchoriza with two species, Ariza with eight species, Galei~hth~vswith two species and Netma with one species, have been reported fiom Mcamostly G. G. Teugelsand G. Gourène - Biodiversityand aquaculture of AfricanCatfish v 237 fi-om coastal bays and estuaries. Some, however, are confined to fi-eshwaters. Morphologically they are recognized by a robust body, compressed posteriorly, three pairs of barbels, dorsal and pectoral fins with strong spines andthe presence of an adipose fin. hius gigm Boulenger, 1911 is exclusively found in fi-eshwater in the Niger and Volta basins. Its maximal length reported is 1.5 m. It has become however, extremely rare. They have not been used in aquaculture in Africa.

Family Plotosidae

Like the , the Plotosidae are mostly marine catfishes found in the western Pacific and the Indian fi-om the east Coast of fica to Australia. One genus, Plotosus, and three species have been reported from the east Coast of Africa. They occasionally enter fi-eshwater. Plotosidae are recognized by an elongated body with a pointed tail. Four pairs of barbels are present. Two dorsal fins are present, the first with a strong leading spine, the latter very long and confluent with the caudal. Caudal andanal fins are alsoconfluent. The pectorals have a strong spine. The maximal size reported is about 600 mm.They are not used in aquaculture.

References

AGNESE (J.-F.), OTEME (Z.J.), of the suspensoriumof primitive GILLES (S.),1994- catfishes (Teleoste: Ostariophysi) Effects ofdomestication ongenetic and their phylogenetic relationships variability, fertility, survival and growth Bonn. Zoo/. Monogr., 32: 1-149. rate in a tropical siluriform; Heterobranchus longifilis BARDACH (J.E.), RYTHER (J.H.), Valenciennes 1840. bhChRNEY (W.O.),1972 - Aquaculture, 131 : 197-234. Aquaculture. The farming and hosbandry of freshwater ARRATlA (G.),1992- and manne organisms. Development and variation Wiley Interscience, NewYork: 868 p. 238 Genebics and aquaculture in Afpiea

BLACHE (J.), MITON (F.), STAUCH (A.), FAGBENRO (O.A.), ADEDIRE (C.O.), ILTIS (A.), LOUBENS(G.), 1964- OWOSEENI (E.A.), AYOTUNDE (E.O.), Les poissons du bassin du Tchad '1933 - et du bassin adjacentdu Mayo-Kebbi. Studies on the biology andaquaculture Etude systématique et biologique. potentiel of feral catfish Heterobranchus bidorsalis (Geoffroy St. Hilaire 4809) (Clariidae). BOULENGER(GA.), 1907- Trop. ZOO!.,6: 67-79. Zoology of Egypt. The Fishes of the Nile published for the Egyptian FlNK (S.), FlMK (W.L.), '198'1 - Government. 2 Vol., London, 578p. Interrelationships of the ostariophysan fishes (Teleostei). Zool. J. Linn. Soc., BOULENGER (GA.), 1911 - 72: 237358. Catalogue of fhe freshwaterfishes of Afmca in the BritishMuseum GARIBALDI (L,), 19%- (Natural History). List of species used The Trustees,Vol. 2, 523 p. in aquaculture. FA0 Fish.Circ., 917: 1-37. CHARDON (M.), 1963 - Anatomie comparée de l'appareil HECHT (T.), LUBLINKHOF (W.), de Weber et des structures connexes KENMUIR (D.),lm1- chez les Siluriformes. Ann. Mus. R. lnduced spawning ofthe Afr. Centr.. '1 ES: 1-227. Heterobranchuslongifilis, and ernbryo surviwl rates of pure andreciprocal DA COSTA (S.), GOURENE (G.j, clariid crosses. TEUGELS(G.G.), 199.3- S. Afr. J. Wldl. Res., 21 : 123-1 25. Embryologie, aspect extérieur du dkveloppement larvaire et maturite HEM (S.),1986 - sexuelle du poisson-chat africain Premiers résultatssur la reproduction (Siluroidei, contrdée de Chlysichthys Clariidae). Belg. Journ. Zool., nigrodigitatus en milieu d'élevage. 126: 93-1 69. pp.189-205. ln Huisman (E.A.), ed.: Aquaculture researchin the Africa DAGET (J.), 1957 - region. Pudoc, Wageningen,274 p. Les eaux et les poissons de Haute Voka. Mém. Ifan. 33: 95-1159. LEGENDRE (M.),TEUGELS (G.G.), CAUrY (C.)%JAMBERT (B.), 1992 - DEVOS (L.)t 'lm- A comparative studyon rnorphology, A systematic revision ofthe African growth rate and reproductionof Clarias (Teleostei, Siluriformes). gariepinus (Burchell, 1822), Ann.Mus.R.Afr. Centr., 271 : 4 -433. Heterobranchuslongifilis Valenciennes, 1840 and their DL4 (A.K.), OTEME (Z.J.), 1986 - reciprocal hybrids (Pisces, Clariidae). Etude de la qualité de l'aliment et de la densité sur le taux desurvie des alevins de ChiysichPhys MlCHA (J.C.),1973 - nigrodigitatus. pp. -163-174. EQde des populations piscicoles In Huisman (E.A.), ed.: AquacuKure de I'lJbangui et tentatives de s&ction research in the Africa region. Pudoc, et d'adaptation de quelques esp&ces Wageningen, 274p. à I'htang de pisciculture. Not. Doc. Pêches Piscic., CTFT: IIOp. EKANEh4 (S.B.),1993 - Water temperature of typical ponds MO (T.), 1931 - and its effect on Anatomy, relationships nigrodigitatus (Lacepedej culture. and systematics of the Bagridae J. Aquac. trop., 9: 144-149. (Teleostei: Siluroidei) G. G. Teugelsand G. Gourène - Biodiversityand aquaculture of AfricanCatfish v239

with a hypothesis PLANQUETTE(P.), 1976- of siluroid phylogeny. Theses Contribution à I'étude de poissons Zoologicae. 17: 1-216. utilisables enaquaculture en eaux chaudes. Observations MslsKA (O.V.), RASHIDI (B.B.A.), sur la croissance et la reproduction KAMVABINGU (Z.E.),1991 - d'Auchenoglanisoccidentalis. Growth performance of aplanktiwrous Not. DOC.Pêches Piscic., clariid, Bathyclarias loweae CTFT, 12: 1-1 1. in anexperimental pond. Aquabyte, 4: 5. TEUGELS(G.G.), 1986a - Clariidae. pp 66-101. In Daget (J.), NGUENGA(D.), BREINE (J.J.),TEUGELS Gosse (J.P.), Thys van den (G.G.), OLLEVIER (F.), 19%- Audenaerde (D.F.E.), eds.: Check-List Artificial propagation ofthe African of the Freshwater Fishes catfish Heterobranchus longifilis ofAfrica.Cloffa 2 ISNB, Bruxelles- (Siluroidei; Clariidae): description Mrac, Termren-Orstom, Paris, of a simpletechnique toawid 520 p. sacrifying male broodfish for theobtention of milt. TEUGELS(G.G.), 1986b- Aquaculture, 143: 21 5-217. A systematic revisionof the African species of the genus Clarias (Pisces; NWADUKWE(F.O.), lm- Clariidae). Ann. Mus. R. Afr. Centr., lnducing oocyte maturation, ovulation 247: 1-199. and spawning in the African catfish, Heterobranchus longifilis TEUGELS (G.G.), 1"- Valenciennes (Pisces: Clariidae), Taxonomy, phylogeny and using frog pituitary extract. biogeography of catfishes Aquac. Fish. Manag. 24: 625-630. (Ostariophysi;Siluroidei) : an overview. Aquat. Liv. Res. OUATTARA(M.), KOUAKOU (K.), GOURENE (G.), 1993 - TEUGELS(G.G.), DENAYER(B.), Une approchetechnologique peu LEGENDRE (M.), lm- onéreuse deproduction de larves A systematic revision ofthe African et d'alevins deChrysichthys catfish genus Heterobranchus (Pisces, nigrodigitatus (Pisces; Bagridae). Clariidae). Zool. J. Linn. Soc., Agron. Afr., 5: 33-38. as : 237-257.