Productive and economic performance of an indoor intensive culture of Penaeus vannamei: comparing biofloc versus recirculating systems

Abstract

This study evaluated the productive performance and economic feasibility of intensive indoor culture of Penaeus vannamei in 2,500 L fiberglass tanks, comparing a recirculating aquaculture system (RAS) and a biofloc technology system (BFT). A 56-day experiment was performed at a stocking density of 750 ind/m3, with four replicates per treatment. Shrimp reared in RAS showed significantly superior growth, reaching greater total length (8.73 ± 1.72 cm) and final body weight (11.22 ± 0.74 g) than those cultured in BFT (5.94 ± 1.29 cm and 9.91 ± 0.71 g, respectively; p = 0.004 and p = 0.002). Feed conversion ratio was significantly lower in RAS (1.42 ± 0.12) than in BFT (1.89 ± 0.15; p = 0.0006), resulting in higher productivity (10.8 ± 0.54 vs. 8.6 ± 0.42 kg/m3; p = 0.0003). Survival did not differ significantly between systems (86.7 ± 2.52% in RAS and 84.1 ± 3.21% in BFT; p = 0.21). Inferior performance of BFT was attributed to limitations associated with small-volume tanks, particularly suspended solids accumulation and biofloc instability which likely impaired oxygen availability and feed utilization. Conversely, RAS provided greater environmental stability, supporting more efficient biomass deposition and consistent growth. An economic analysis based on RAS performance and extrapolated to a commercial-scale scenario estimated an annual production cost of US$ 24,249.24 for six production cycles. Feasibility was confirmed by internal rates of return ranging from 19.12% to 68.01% and net present values between US$ 5,290.48 and US$ 49,226.62, depending on shrimp survival (80-90%) and market price (US$ 7.00-8.00 kg-1). Under optimal conditions, the payback period was 1.8 years. Overall, RAS showed clear biological and economic advantages over BFT for intensive shrimp farming with reduced water use.