Evaluation of growth performance of Clarias gariepinus and Heterobranchus longifilis under communal and separate culture conditions
A study was carried out to evaluate the performance of Clarias gariepinus and Heterobranchus longifilis cultured separately and together in communal culture conditions. The performances of the species were compared based on growth rate, condition factor, survival and harvest biomass at the end of the study. The investigation was carried out for 90 days in 3 x 3 completely randomized designs. The fishes were fed twice daily with 42% crude protein commercial diet in a flow through tank culture system. Water temperature, dissolved oxygen and pH were monitored during the study. Growth was fastest in separate culture of C. gariepinus followed by the culture of the two species in communal system. Lowest growth was recorded in separate culture of H. longifilis. The above results were attributed to higher feeding propensity of C. gariepinus. The high feeding rate of C. gariepinus made the species to grow fast in separate culture. H. longifilis learned voracious feeding in the communal system and grew better in the system than in separate culture. The slower growth of C. gariepinus in communal culture was attributed to loss of feed to competition with H. longifilis. The report suggested that the situation can be remedied with increased feeding to accommodate higher appetite of H. longifilis in communal system. Highest mortality was recorded in separate culture of H. longifilis, while highest survival was recorded in separate culture of C. gariepinus. This may be due to handling stress as the deaths were recorded after sampling. This implies that H. longifilis is more likely to die from handling stress than C. gariepinus.
Keywords: African catfish, Cohabitation system, increase in size, isolated system, mortality