GROWTH AND PRODUCTION OF PANGAS Pangasius hypophthalmus AND MARIGOLD Tagetes erecta IN FRP MADE NFT AQUAPONICS SYSTEM

Culture experiment was carried out for 90 days (October-December 2018)  in Nutrient Film Technique (NFT) Aquaponics System designed and developed in Fibre Reinforced Plastic (FRP) material under AICRP on Plasticulture Engineering and Technology Centre at ICAR-CIFA, Bhubaneswar to determine the growth of Pangas, Pangasius hypophthalmus with Marigold, Tagetes erecta. The experiment was conducted in triplicate. Each system comprising of a circular fish culture tank (Ø 2.15×0.9 m) with an operational capacity of 2800 l, trickling biofiltration unit utilizing 85 L volume filled with 10-25 mm gravels and seashell (S:V=12.77), hydroponics tanks (4×0.9×0.35 m) with an optimum water column of 0.25m containing trays with 72 perforations (Ø2.5") to hold the plastic mesh pots and a 200 l sump made off HDPE with three conductive water level sensors and a 0.3HP submersible water pump for the recirculation.

Whole cycle is divided into four simple stages as illustrated in the Figure. Effluents from the fish culture tank passes through the biofilter in a bottom to top fashion following fluid flow under the influence of gravity at a rate of 234.8 l/hr/sq.m. The bio-filter contains substrate for colonization of nitrifying bacteria. Filtered water from bio-filter trickles directly into the hydroponics tanks. The depth of water in hydroponics tank is set to be maintained at 0.25m, which helps the whole length of the plant roots to be submersed in the nutrient rich water, so that the nutrient film can be optimally utilized with minimal loss. Water from hydroponics tank travels into the sump through an outlet of 1.5" diameter. As the sump fills up to 190 l, sensors signal the control unit, which activates the pump and hence water is pumped back to the fish culture tanks.

Fish were stocked in culture tanks @150 fish/ tank and raised with marigold plant for a period of 90 days. The Initial length and weight of P. hypophthalmus were 64.9±0.58 mm and 2.87±0.19 g, respectively. The marigold T. erecta with initial heights 145.2±0.58 mm were planted in hydroponics tank. Results found that there was no significant difference (p > 0.05) in the fish and plant growths and production parameters between replicates at the end of the experiment. The average fish length and weight were 119.4±1.2 mm and 14.28±0.48 g respectively at the end of experiment. The final height of T. erecta plants were 458.3±12.2 mm. There was no significant difference in weight gain (14.29 ±0.48 g/fish), feed conversion ratio (1.57±0.04), and specific growth rate (1.78±0.04) of fish. The average survival of fish was 94%. The total productions of Pangas and Marigold were 2.296 kg/cu.m and 384±21 number of flowers (798.0±33.6 mm diameter and 16.67±0.93 g weight) respectively.