Advances in the production and removal of off-flavors in Recirculating Aquaculture Systems (RAS) for the cultivation of freshwater fish

Recirculating Aquaculture Systems (RAS), as an advanced aquaculture technology, achieve efficient utilization of water resources and a significant reduction in feed consumption through meticulous system management and the application of cutting-edge engineering techniques. Despite these advancements, the accumulation of metabolic waste generated during the cultivation process may trigger severe odor issues, posing a potential threat to the stability of the cultivation environment and production efficiency. This review comprehensively examines the mechanisms of odor generation in RAS systems and provides an in-depth analysis of the origins and influencing factors of two key odor-causing substances-geosmin (GSM) and 2-methylisoborneol (2-MIB). Furthermore, this paper systematically reviews the latest research progress in odor removal technologies within RAS systems, covering a variety of methods including biological, physical, and chemical treatments. By thoroughly comparing the advantages and disadvantages of these technologies in terms of efficiency, cost, ease of operation and environmental friendliness, this article aims to provide a theoretical basis and practical guidance for the further optimization and application of RAS technology, with the expectation of promoting the sustainable development of recirculating water aquaculture technology.