Establishment of season-specific nutrient thresholds and analyses of the effects of nutrient management in eutrophic lakes through statistical machine learning

•Chlorophyll a predicted by statistical machine learning successfully displayed seasonal variations.•Estimated nutrient thresholds were quite variable and higher in summer than in winter.•Reducing TP concentration in these lakes in summer is important to control algal growth.•Seasonal variation in nutrient concentration should be considered when establishing criteria.