The Productivity of Using Current Generating Circular Tanks for Tilapia Fingerling (Oreochromis niloticus (Linnaeus, 1758)) Production

This research conducted to determine the optimum water current models for growth performance and survival rate of tilapia fingerlings (O. niloticus) in circular tanks. The method used in this research is Completely Randomized Design (CRD), which consists of three treatments and four replications. The treatments are circular tanks without water current (control), circular tanks with 0.1 m s-1 water current and circular tanks that combine 0.1 m s-1 water current with venturi aeration. Tilapia fingerlings were kept in circular tanks with 30 cm diameter and 37 cm of height, with water level of 30 cm. 50 fingerlings with size of 2-3 cm were reared in every circular tank. The feed is given 3 times daily with a feeding rate of 5% from biomass. Absolute growth rate, specific growth rate, survival rate, feed conversion ratio and feed efficiency were observed every ten days, while water quality was assessed weekly. After 42 days of rearing, the results showed that the 0,1 m s-1 water current combined with venturi aeration had the highest dissolved oxygen level (6.5-7.3 mg L-1), the lowest ammonia levels (0.15-0.20 mg L-1), 92% survival rate, 1.17 g absolute growth rate, 3.65% specific growth rate, 1.3 feed convertion ratio and 77.8% feed efficiency.