United Arab Emirates (UAE), as an arid land country witnessing shortage of water and lacking in arable fertile land. However, UAE has made important progress to enhance its food security, but still food security and agriculture stability strongly addressed as real future challenges. In latest years, aquaponics system has gained high attention especially in connection of the efficient use of water and nutrients for an optimized aquaponics system. As a result, aquaponics would contributes to the sustainable agriculture in the dry areas by producing organic vegetables, fruits, and fish. The current experiments presented in this research were aimed to investigate the impact of varying Tilapia (Oreochromis niloticus) feeding frequency and stocking density on production of fish and quality of organic lettuce produced in an aquaponics system.
Experiment 1. Feeding Frequency: Three fish tanks, each stocked with 100 fish/m3, were used to investigate the effect of feeding frequency of one time, two times and three times per day.
Experiment 2. Fish Stocking Density: Three fish tanks, each stocked with 100 fish/m3, 120 fish/m3 and 140 fish/m3 of Oreochromis niloticus fingerlings with approximately an average weight of 15-20g. The Nile tilapia were fed while floating with a commercial feed of 36% protein.
Both experiments were lasted for three months with a replicated study. Lettuce was seeded in a culture raceway in each experiment. At the end of each experiment, the tilapia growth and growth parameters namely, fish weight gain (WG), feed intake (FI), and feed conversion ratio (FCR), protein and fat deposition values were measured or calculated. In parallel, the aquaponic system water quality (pH, temperature, total dissolved solids, dissolved Oxygen, total ammonia, nitrite, and nitrate) and water consumption were analyzed at specified intervals. Total production for fish and lettuce are shown in Table 1. & Table 2.
In conclusion, feeding frequency of three times per day and stocking density of 140 fish/m3 are shown better lettuce production. Fish production was not affected by both feeding frequency and stocking density. Water quality also affected by increasing feeding frequency and stocking density.