Water quality of inlet water and pond water in representative aquafarms had been monitored in order to investigate the pollution status of nitrogen and phosphorus in freshwater aquaculture in Shanghai.The results showed that the annual average concentrations of total nitrogen(TN)and total phosphorus(TP)were 2.53 mg/L and 0.294 mg/L,respectively,without significant difference in TN concentration between the inlet water and pond water.The annual average concentration of TP was 0.370 mg/L in the pond water,sig...