NEW CATFISH SPECIES FOR THE DEVELOPMENT O F FISH CULTURE IN AFRICA

Besides Clarias gariepinus introduced in aquaculture in the early 1970 s, other African catfishes (Siluroidei) have been studied for their po tential in aquaculture for about 15 years. These belong to the genus C hrysichthys (Claroteidae) and Heterobranchus (Clariidae) investigated in Ivory Coast, Nigeria and Benin, and mainly in the context of a brac kish water aquaculture in lagoon or estuaries. It is in the Ivory Coas t in the early eighties that reproduction in captivity of Chrysichthys nigrodigitatus, and then of Heterobranchus longifilis, was obtained f or the first time as a result of research carried out within the Ivori an Oceanologic Research Center (CRO) in Abidjan. Nowadays, the breedin g cycles of both species has been achieved and extension towards the p roduction sector has been initiated. Production of C. nigrodigitatus i s mainly monospecific? intensive or semi-intensive, in lagoon enclosur es (Ivory Coast) or in brackish-water ponds (Nigeria). In Ivory Coast, its culture became significant since 1990 with an annual production o f 200-300 tons. The biology of H. longifilis is similar to that of C. gariepinus, but the former presents the advantage of a faster growth. The commercial production of this species is now beginning in Ivory Co ast. intensive rearing of H. longifilis in lagoon enclosures appears a s an appropriate option, but promising results have also been obtained in freshwater ponds. Based on the Ivorian experience, H. longifilis a quaculture development projects are currently carried out in Niger and Cameroon. The recent literature reports also culture trials with H. b idorsalis in Nigeria. Intergeneric hybrids between H. longifilis or H. bidorsalis and C. gariepinus have been produced in South Africa, Ivor y Coast and Nigeria. However, the real advantage of using the hybrids instead of the parental species for aquaculture remains to be demonstr ated. The results obtained so far show that the culture of C. nigrodig itatus and H. longifilis constitutes now a possibility of diversificat ion, and even an alternative to the use of C. gariepinus, for African aquaculture. A synthesis of existing data on the biology and culture o f these species is presented.