Optimising the control factors of a smart biofloc aquaculture system for the sustainable production of Pacific whiteleg shrimp, Litopenaeus vannamei

Abstract

Despite the growth in aquaculture, there are uncertainties over its sustainability as the global population is projected to hit 9.6 million in 2050 with an estimated demand gap of 21.6 million metric tonnes. Prominent among the challenges is the sub-optimal performance of culture systems. There is a need to improve the systems using scientific approaches for optimum production. This research optimised the control factors of a traditional biofloc system using water quality conditions for the setup of an indoor multi-techno aquaculture system (IMTAS). IMTAS is a fully automated culture system controlled by internet of things (IOT). Taguchi L9 design and grey relational analysis (GRA) were used to determine the optimum levels of three control factors, namely stocking density, carbon-to-nitrogen ratio (C/N ratio), and probiotic dosage. Water quality parameters were measured as response factors over a culture period of 12 weeks. During a Taguchi single-response optimisation, the signal-to-noise ratio (S/N ratio) identified optimum levels for total ammonia nitrogen in run 7 (0.309), nitrite, phosphate and pH in run 1 (7.929, 17.960 and 17.588 respectively), dissolved oxygen in run 6 (15.265), electrical conductivity and temperature in run 5 (93.861 and 29.227), total dissolved solids in run 2 (88.986) and salinity in run 4 (30.972). The Taguchi-based GRA further consolidated these levels to determine the optimum stocking density as 200 shrimp.m−3, C/N ratio of 15 and probiotic application dosage of 14 ml.l−1. Probiotic was evaluated as the most substantial control factor that enhanced the performance of this smart culture system.