Performance evaluation of different bedding media in aquaponic system for growth and production of okra and tilapia

Abstract— Aquaponics is the marriage of aquaculture and hydroponic technologies. Present research was accomplished to evaluate the relative performance of only gravels (T1), only coconut husk (T2) and mixture of gravels and coconut husk (1:1 in volume) (T3) as media in aquaponic system to grow okra (Abelmoschus esculentus) and tilapia (Oreochromis niloticus). Each treatment had three replications of similar bedding media. Nine food grade plastic containers filled with media and a 180 liter plastic water tank were used to construct the aquaponic system for growing okra and tilapia, respectively. In each bedding container, 4 okra seeds were sown and tilapia with initial length of 13.65 ± 1.88 cm and weight of 46.04 ± 20.93 g were stocked at the rate of 144 fish/m3 in the fish tank. Tilapia were fed twice a day at the rate of 3% for premier month, 2% for next month and 1.5% of body weight for the remaining time. Fish and plants were sampled biweekly during the whole study period. Data analysis revealed that the treatment T3 performed best followed by T1 and T2, respectively in terms of okra plant growth performances with respect to duration of plant growth in different growth stages, plant height, leaf number per plant, leaf area and branch number per plant. Okra production was shown significantly greater (P ≤ 0.05) in the treatment T3 (9.08 ± 1.25 kg/m2/157 days) pursued by T1 (7.5 ± 1.83 kg/m2/157 days) and T2 (3.83 ± 2.33 kg/m2/157 days), respectively. At the termination of the study, the length gain and weight gain of tilapia were 6.64 ± 0.1 cm and 104.76 ± 20.78 g, respectively. Total tilapia yield was recorded 138.80 tons/ha/157 days with 92.3% survival and FCR of 1.96. The water quality parameters and the nutrient concentrations in influent and effluent water remained within suitable ranges for tilapia production as well as the growth of okra. Therefore, the mixture of gravels and coconut husk media showed incentive performance in plant growth and production of okra compared to the individual media and at the same time the tilapia production was also satisfactory