BIO-INTEGRATION OF NILE TILAPIA Oreochromis niloticus AND SPINACH Spinacia oleracea IN LOW SALINE UNDERGROUND WATER

An experimental trial of 45 days was conducted to optimize Nile tilapia (Oreochromis niloticus) to spinach (Spinacia oleracea) ratio in a recirculating aquaponics system using inland saline groundwater of salinity 3 g l^-1. Different fish to plant ratios, T1 (1:0.7), T2 (1:1), T3 (1:1.3) were assigned as treatments, whereas C1 (aquaponics without plants) and C2 (without hydroponic component) were assigned as control groups. Average weight of O. niloticus (23.46±0.24 g), spinach yield (1.42±0.02 Kg/bed) and percentage removal of nitrate (50.43±0.11%), phosphate (47.62±2.20%), potassium (54.26±1.23%) from the effluent (Figure 1) was found to be significantly (P < 0.05) higher in T3. The daily water requirement of T1, T2, T3 and C1 (1.16-1.29%) was significantly (P < 0.05) lower compared to C2 (20.33%). Findings of the experiment suggest that aquaponics is feasible with low saline undergroundwater and a ratio of 1:1.3 (Nile tilapia : spinach) is optimum for balancing nutrient generation and removal for the best fish and plant production.