Abstract

Geometry of fish tanks tends to affect the growth and yield of fish. The impact of tank geometry on the production of Clarias gariepinus was evaluated. Circular, rectangular and ellipsoid tanks were used to test the variation of water temperature, pH, dissolved oxygen and total suspended solids on African catfish growth performance. Results on water temperature, pH, DO, were within the acceptable ranges of 24.9-25.9°C, 6.39-7.52 and 5.81-8.32 mg/l, for circular tank; 25.1-26.1ËšC, 6.49-7.53 and 3.96-8.53 mg/l, for rectangular tank; and 24.5-26.2°C, 6.49-7.50 and 5.08-8.43 mg/l, for ellipsoid tank; respectively. Weight gain ranged from 14 to 576 g, 13 to 330 g and 14 to 557 g; feed conversion ratio (FCR) ranged from 1.11-1.33, 1.23-1.54 and 1.22-1.34; specific growth rate (SGR) ranged from 0.40 g/day to 3.64 g/day, 0.11 to 2.27 g/day and 0.79 to 3.12 g/day; survival rate were >88, >84 and >92% for circular, rectangular and ellipsoid tanks, respectively. Except for weight gain and FCR, all other parameters (length increment, SGR and survival rate) showed no significant difference (P = .05) among the 3 tank geometries. Benefit cost ratio (BCR) for the circular, ellipsoid and rectangular tank was 1.12, 1.13 and 0.79, respectively.

Key words: Aquatic system, benefit-cost, ellipsoid tank, growth performance, mudfish.