The effect of circulation rate on the water quality of container-type recirculation aquaculture system under different feeding rates of Schizothorax wangchiachii

As an experimental fish, juvenile Schizothorax wangchiachii were fed different dosages (100, 300, or 500 g), and the changes in water quality in the inlet and outlet of the biofilter and in the aquaculture buckets were measured under different circulation rates (1.5, 3, or 4.5 m3/h; water samples were collected every 2 hours). With 100 g of feed and different circulation rates (1.5, 3, or 4.5 m3/h), the average removal rates of ammonia nitrogen and nitroso nitrogen by the biofilter were 40.4, 36.8, and 27.7% and 43.9, 36.9, and 29.8%, respectively. With 300 g of feed, the average removal rates of ammonia nitrogen and nitroso nitrogen were 42.3, 37.9, and 33.6% and 45.8, 32.7, and 21.7%, respectively. With 500 g of feed, the average removal rates of ammonia nitrogen and nitroso nitrogen by biofilters with different circulation rates were 53.5, 42.6, and 35.7% and 40.3, 26.5, and 18.1%, respectively. Therefore, when the feeding amounts were 100, 300, and 500 g, respectively, the optimal circulation rates were 1.5, 1.5, or 4.5 m3/h, which allowed the best management and reduction in energy consumption of the circulating aquaculture system. This research conclusion provides a reliable scientific reference for the promotion of a low-cost new model of industrial circular water aquaculture.