ECONOMIC EVALUATION OF TILAPIA FINGERLINGS AND LETTUCE PRODUCTION IN AN AQUAPONICS SYSTEM IN BRAZIL

The literature on Brazilian aquaponics is incipient. While some experiments have been done, there are only few reported relevant economic results. There is economic and environmental potential for aquaponics activities in Brazil given the sustainable characteristics of the production and the water shortage problem i n some regions. Therefore, this study intends to fill the gap in the literature by evaluating the economic returns to aquaponics with different levels for key control variables in the production system.

The input variables considered in this study are fish stocking density (fish/m3) and quantity of fish feed (% difference relative to the factory recommendation).  The output attributes at harvest time (lettuce and fish) are color (on a classification scale of three color shades between yellow and green) and weight (grams) of lettuce and weight (grams) of the fish (tilapia) .  The final output for fish to be analyzed is juveniles (big fingerlings) that have a good market potential and can be harvested within the 30-day production. Output levels were measured every day starting on the 20th day of experiment.

The data needed was collected from an experiment conducted at UNESP (Sao Paulo State University) in Brazil.  The facilities  utilized included  16 aquaponics units with three rows of plants each, where different levels of the same variable were measured at the same time. Fo ur  different levels of density and  four levels of fish feed were measured in a 30-day experiment.  An analysis using linear programming was done to identify which combinations of fish density, feed level and harvest day are economically efficient. A cash flow was also calculated for  selected efficient systems to show the economic feasibility of the most efficient combination. Figure 1  summarizes the experiment scheme.