In Situ Biofilm Aquaculture Systems (In Situ BFSs) for Litopenaeus vannamei: A Review

The scale of intensive Litopenaeus vannamei aquaculture has increased over the past few decades. However, the inorganic nitrogen and suspended solids (SSs) generated during the aquaculture process are toxic to shrimp and have negative environmental effects. Therefore, removing these pollutants from aquaculture systems is a critical issue that must be addressed. In addition to the widely used recirculating aquaculture systems (RASs) and biofloc technology (BFTs), the addition of submerged substrates to L. vannamei aquaculture tanks to construct in situ biofilm aquaculture systems (in situ BFSs) is an alternative that results in favorable water quality and enables low or zero water exchange, significantly improving shrimp performance and decreasing the feed conversion ratio (FCR). This review highlights the principles, construction methods, water treatment effectiveness, and impact of in situ BFSs on L. vannamei growth as well as pathogen control. The selection of appropriate substrates and methods for nitrifying biofilm cultivation and substrate fixation can significantly affect water treatment efficiency, reduce the concentrations of harmful substances (SSs, ammonia and nitrite) and provide additional nutrients and habitats for L. vannamei, thereby increasing their survival rate and enhancing their growth performance. In addition, the integration of in situ BFSs with BFTs and algal-symbiotic systems is discussed. In this paper, the potential for further increasing the treatment capacity of in situ BFSs through sulfur autotrophic denitrification (SAD) and electric field-assisted biofilm systems is proposed. The application of these innovative technologies is expected to provide new insights and solutions for achieving sustainable development in L. vannamei aquaculture.