The objective was to measure biochemical components and energy density in muscles of Coilia mystus,C.ectenes and C.ectenes taihuensis in spawning season.At the same time the nutritive quality was evaluated and the influence on biochemical components of different ecological habits was also explored.In this experiment,fifty female samples with ovary in stage Ⅴ of each population were collected from Changxing Island(Shanghai,China),Xuliujing-Tiehuangsha(Changshu,China),and Wuli Lake(Wuxi,China) respectively in 2008 from May to July,and correlative indexes of each population were tested with average results of three duplicates.The results showed that the contents of moisture were 74.62%-81.87%,crude protein 15.06%-18.08%,crude fat 1.65%-6.78% and ash 0.98%-1.49% based on fresh muscles,and the energy density showed 4.447-7.209 kJ/g.The essential amino acid indexes were 70.49-76.04.Contents of unsaturated fatty acid were 62.50%-72.48%,of which ω-3 polyunsaturated fatty acid accounted for 6.54%-8.39%.Among mineral elements contents K showed the highest value while Cu showed the lowest.The results indicated that three populations of the genus Coilia all were ideal protein sources,which contained plenty of poly-unsaturated fatty acid,mineral elements,and some other essential factors,such as lysine,branched-chain amino acid,EPA and DHA.By means of comparative analysis on biochemical components,it could be found that crude fat and energy density of C.ectenes were significantly higher than those of C.mystus and C.ectenes taihuensis,the remarkable difference indicated that the energy reservior for reproductive migration might come from the fat accumulation,which also showed the significant influence of migration behavior on biochemical components.