Aquaponics for Improving High Density Fish Pond Water Quality Through Raft and Rack Vegetable Production

The population of Bangladesh is increasing tremendously and to keep pace with the increasing demand of fish protein, farmers intensified fish production from the water bodies which created environmental pollution. To tackle the situation the raft and rack aquaponics experiment was conducted to reduce the water pollution and have vegetable production from high density poly-culture fish ponds. Three ponds were selected each having an area of 3.12 decimal. The bamboo made raft was placed on water surface and rack on the bank of pond 1 which denoted as treatment T and only raft was placed in pond 2 that noted as treatment T and 1 2 pond 3 was without any raft and rack denoted as control (T ). Summer vegetables were planted in both the rafts 3 and rack in two liter plastic water bottles. The vegetable growth and water quality parameters such as NH /NH , 4 3 NO , NO , PO , DO and pH were measured fortnightly using test kits. Pungasius and tilapia were released as 3 2 4 the experimental fishes at the rate of 33,650 and 16,000 fish/ha. Data interpretation showed that % SGR per day of pungasius and tilapia in T , T and T were 2.57 and 0.822, 1.27 and 0.795, 2.36 and 0.438 respectively. The 1 2 3 highest growth was found in T treatment for both species. The water quality parameters were within the 1 accetpable limits but were significantly different among the treatments. The water quality in T and T 1 2 tresatments were better than the T . The production of water spinach, pudina and okra from raft and rack were 3 about 997 and 2460; 797 and 1969; 199 and 492 kg/ha/90days respectively in T . In T only okra production was 1 2 higher than T (215kg/ha/90days) but water spinach and pudina production was lower than T (923 and 763 1 1 kg/ha/90days). The pudina production was highly profitable than the other crops and benefit-cost ratio of pudina was about 6.33. So, along with the fish culture, farmers can produce vegetable through raft and rack aquaponics and can improve the pond condition. The technology can be piloted in different agro-ecological zones in the country.