Aquaponics is the combined culture of fish and hydroponic plants in recirculating systems. Aquaculture effluent provides most of the nutrients required by plants if the optimum ratio between daily feed input and plant growing area is maintained. An experiment was conducted in an outdoor, commercial-scale aquaponic system on 0.05 ha of land in the tropics. The objectives were to determine the production of tilapia and basil using batch and staggered cropping systems, compare aquaponics with field crop production and evaluate the ratio of feed input to plant growing area. The projected annual production of tilapia was 4.37 t. The mean yield of basil was 2.0, 1.8 and 0.6 kg/m 2 using batch, staggered and field cropping systems, respectively. Projected annual production of the system was 5.0 t of basil with staggered production. Nutrient deficiency symptoms appeared only in the batch-cultured basil. The feed input ratio was 81.4 g/day/m 2 for batch culture and 99.6 g/day/m 2 for staggered production. Staggered production moderated the uptake of nutrients. Basil production is sustainable in an aquaponic system with a feed input ratio of 99.6 g/day/m 2 and a staggered cropping system. several types of lettuce (Lactuca sativa). The present study was conducted to determine the production of tilapia and basil (Ocimum basilicum 'Genovese') in this aquaponic system, using batch and staggered cropping systems, compare it to field crop production and evaluate the ratio of feed input to plant growing area. MATERIALS AND METHODS The UVI aquaponic system was situated outdoors and consisted of four fish rearing tanks (7.8 m 3 each), two cylindro-conical clarifiers (3.8 m 3 each), four filter tanks (0.7 m 3 each) containing orchard netting, one degassing tank (0.7 m 3), six raft hydroponic tanks (each of which was 11.4 m 3 and measured 30.5 m by 1.2 m by 30 cm: total hydroponic growing area was 214 m 2), one sump (0.6 m 3) and one base addition tank (0.2 m 3) (Fig. 1). Total system water volume was 110 m 3. The fish rearing and hydroponic tanks were each aerated by separate 1-hp blowers and air stones. A ½-hp water pump circulated water at a rate of 378 L/min. Average retention time was 1.4 hours in the fish rearing tanks and 3.0 hours in the hydroponic tanks. With the exception of the hydroponic tanks, all other tanks were situated under an opaque canopy. The production unit occupied 0.05 ha of land. Prior to initiating the experiment the fish rearing tanks were in continuous operation for the production of Nile tilapia (Oreochromis niloticus) or red tilapia (Oreochromis sp.). Fish production cycles were 24 weeks. Production within the four rearing tanks was staggered so that one tank was harvested every 6 weeks. Nile tilapia fingerlings were stocked at 77 fish/m 3 while red tilapia fingerlings were stocked at 154 fish/m 3. Fingerlings averaged 70 g. The fish were fed three times daily ad libitum for 30 minutes with a complete diet of floating pellets containing 32% protein. Within 2 weeks of initiating the first basil trial usin...

Aquaponics is an integrated fish and plant recirculating production system. The University of the Virgin Islands' raft aquaponic system uses a cylindro-conical clarifier as a primary solids removal device; however, a swirl separator may offer advantages. The objectives of the 8-wk experiment were to compare water quality parameters, Nile tilapia, Oreochromis niloticus, production and water spinach, Ipomoea aquatica, production in a raft aquaponic system using a clarifier or swirl separator for primary treatment of solids in the waste stream.No significant differences (P ≥ 0.05) existed between treatments for temperature, oxygen, pH, total suspended solids, alkalinity, electrical conductivity, total ammonia-nitrogen, nitrite-nitrogen, nitrate-nitrogen, macronutrients, and micronutrients concentrations in the culture water. There were no significant differences (P ≥ 0.05) between treatments for Nile tilapia production, average weight, survival, or feed conversion ratio. There were no significant differences (P ≥ 0.05) between treatments for water spinach production or plant tissue analysis. In conclusion, the swirl separator used in this experiment performed similar to the clarifier and water spinach grew vigorously in the raft aquaponic system.

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To date, most aquaponic research has been conducted outdoors in tropical climates or in greenhouses in subtropical climates. For more northerly latitudes, aquaponic production will require supplemental light in greenhouses or insulated buildings. Two separate 3-wk growth trials were conducted to evaluate the effects of four different lighting technologies on the growth of Swiss chard, Beta vulgaris (Trial 1) and kale, Brassica oleracea (Trial 2) in aquaponic systems. Light technologies evaluated included fluorescent (FLO), metal halide (MH), induction (IND), and light-emitting diode (LED). Four 1175-L systems were used with all four light types represented in each system in a complete block design. Juvenile Nile tilapia, Oreochromis niloticus (241 g) were stocked in each system and fed a floating 32% protein diet at a rate of 60 g/m 2 of plant grow space per day. In Trial 1, Swiss chard plants grown under LED lights for 3 wk achieved significantly higher (P ≤ 0.05) average individual weights (117.7 g), higher production per unit of area (3535 g/m 2 ), and higher production per unit of energy (32.3 g/m 2 /kwh) than Swiss chard grown under the other three light types, which did not differ significantly (P > 0.05) from each other. In Trial 2, kale grown under LED lights achieved significantly higher (P ≤ 0.05) average individual weights (102.9 g), higher production per unit of area (2136.6 g/m), and higher production per unit of energy (381.5 g/m 2 /kwh) than kale grown under the other three light types, which did not differ significantly (P > 0.05). The results of the two trials are in agreement and indicate that LED lights were superior to MH, FLO, and IND lights in terms of absolute plant growth as well as growth per unit of energy consumed.

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