Reducing the feed input per unit of plant area as a means to improve the efficiency of sea asparagus and Pacific white shrimp biofloc technology‐based aquaponics

This study aimed to evaluate different feeding rate ratios in a biofloc technology-based aquaponics system employing sea asparagus (Sarcocornia ambigua) and Pacific white shrimp (Litopenaeus vannamei) in an 83-day experiment. Two treatments were evaluated: 100 and 50 g feed m−2 day−1, which were achieved by doubling the plant production area from 0.4 m2 to 0.8 m2. Shrimps (1.39 g ± 0.06 g) were reared under an initial density of 250 animals m−3 in 800 L polyethylene tanks, while the plants were cultivated using nutrient film technique hydroponic benches which received water from the shrimp unit through a pumping system. The increase in plant production area allowed for a statistically significant increase in the plant final biomass in approximately 74% (p < 0.05), with the end result that plant productivity was not altered (p ≥ 0.05). Shrimp growth performance and the concentrations of nitrogen compounds and orthophosphate did not differ significantly between treatments (p ≥ 0.05). In conclusion, the reduction in the feeding rate ratio from 100 to 50 g m−2 day−1 did not impair plant productivity, which indicates that the efficiency of the system was improved, as a greater plant biomass was produced with the same amount of shrimp feed inputs.