Comparative Growth Performance of Indian Major Carps and Exotic Carps in an Aquaponics System with Cucumber (Cucumis sativus)

Abstract

The present study was conducted to reveal the best species combination of indigenous carps (Catla catla, Labeo rohita) and exotic carps (Cyprinus carpio, Ctenopharyngodon idella) with the cucumber plant (Cucumis sativus) in an aquaponic system. The aquaponic production system is one of the useful approaches which combine fish and plants with the recycling of waste and conservation of water. This technique combines recirculating aquaculture with hydroponics for the production of two products at a time by utilizing nutrients generated from the system for plant growth. The experimental set-up consisted of 3 treatments in triplicates having a control in each trial. The species composition in different treatments was rohu + catla, rohu + common carp and grass carp + common carp in 70: 30 ratio @ 2000 g/m3 integrating cucumber plantlets @32/ m2 in T1, T2 and T3 respectively. The control in each treatment consisted of the same species composition but without plants. Fishes were fed @ 4% of their body weight during the trial period. Water quality parameters such as temperature, dissolved oxygen and pH were observed daily whereas hardness, alkalinity, ammonia, nitrite and nitrate were recorded @ 20 days intervals. Though the values of ammonia, nitrite and nitrate were found to be marginally higher in controls compared to treatments and a reverse trend was found in the values of dissolved oxygen there were no significant variations in the values and were in their optimal range. The fish growth parameters such as weight gain, percentage weight gain, specific growth rate, daily weight gain, feed efficiency ratio, and protein efficiency ratio were calculated. The result revealed that the highest body weight gain was in catla in the T1 (89.76±0.20g) followed by common carp in T3 (85.43±0.06 g) and grass carp in the T3 (81.76±0.41g) and the lowest in the rohu in T2 (66.03±0.29g). The final average body length of the grass carp and common carp in the T3 was (19.4±0.56cm > 18.6±0.26cm and 17.3±0.47cm > 16.8±0.32cm). Among the treatment, the final average body length was highest in the catla in T1 (20.4±0.37cm) followed by grass carp in T3 (19.4±0.56cm) and    rohu in the T1 (18.1±0.11cm) and the lowest was recorded in the common carp in the T2 (16.4±0.17cm. It is concluded that that in an aquaponic system with grass carp with common carp, 2000g/m3 in combination with cucumber at 32plants/m² will be economically viable for farming practices. Further, more research may be carried out to increase the stocking density of both fish and plants to get maximum profit from this intensive aquaponic system with sustainable strategies.