Based on data from the aquaculture sea-areas of the middle part of Xiangshan Harbor surveyed in autumn of 2014, and spring, summer, and winter of 2015, nutrient levels and seasonal variation in nutrients were evaluated. The results showed that the inorganic nitrogen and phosphorus levels in autumn were higher than those in spring, summer, and winter. Among all regions, the DIN(Dissolved inorganic nitrogen) concentrations in Ninghai seaweed and Xihu Harbor kelp culture areas were higher than the fourth level...