Comparative Evaluation of the Nile Tilapia, Oreochromis Niloticus (Cichlidae), the Catfishes, Chrysichthys Nigrodigitatus and C. Auratus (Claroteidae) for Semi-Intensive Polyculture in Ghana

Two separate experiments were conducted in 0.2 ha earthen ponds for 330 and 130 days, respectively, to evaluate culture performance of sex-reversed all-male Nile tilapia (Oreochromis niloticus), and Catfishes (Chrysichthys nigrodigitatus and C. auratus) in polyculture when fed on rice bran and groundnut bran. Stocking rates of the three species ranged from 6,250 to 12,500, 2,500 to 5,000 and 3750 to 7,500 fish ha-1 pond-1, respectively. In experiment I, mean daily weight gains (g day-1) and survival (%) of Nile tilapia (0.31 ± 0.02 g day-1; 78.1 ± 11.8 %) and C. nigrodigitatus (0.27 ± 0.15 g day-1; 76.9 ± 0.4%) were higher (P < 0.05) than those for C. auratus (0.14 ± 0.01 g day-1; 61.0 ± 0.6%). In experiment II, no differences (P > 0.05) in growth and survival performance were observed among the three species. The superior first-year growth performance of C. nigrodigitatus compared to that of C. auratus suggests higher potential of C. nigrodigitatus for improved fish yield in Nile tilapia-based polyculture systems