Aquaponic production of ornamental koi carp (Cyprinus carpio linn.) and lettuce (Lactuca sativa) in comparison with traditional fish culture and hydroponics system

The study was conducted for comparative analysis of the production of ornamental fish, koi carp (Cyprinus carpio Linn.) and lettuce (Lactuca sativa) in aquaponics and traditional culture system. The experimental fish were stocked at three stocking densities, i.e., 20 m^-3 (SD1), 30 m^-3 (SD2) and 40 m^-3 (SD3) in circular cemented tanks (10m^-3) of the aquaculture unit and lettuce were planted (plant to plant spacing of 12 cm) in the hydroponics unit (HM) of automated aquaponics system. For comparison with the traditional system, koi carp were stocked in cemented tank of equal size (10m^-3) at a standard stocking density of 2 m^-3 and lettuce was planted as per standard protocol i.e. plant to plant space of 30 cm in outdoor conditions in soil bed traditional system (SM) The water quality parameters in both aquaponics and traditional tanks remained in optimum range for fish culture along with >95% of nutrient removal by lettuce. The survival (%) of fish was maximum in control (93.33%) followed by SD3, SD1 and SD2. The final total body length and body weight was significantly higher in control, but the average fish yield (kg m^-3) was significantly higher in all aquaponic tanks, with the maximum yield of 3.73 kg m^-3 (9.56 times) in SD3 (40 m^-3). The lettuce yield (32.2 q acre^-1) was 1.15 times higher in the hydroponic unit, with significantly higher pigment content and insignificant differences for nutrient content except fibre.