Abstract: In order to study the accumulation and consumption of nutrients of Mytilus coruscus in different gonad developmental stages, the values of meat condition index, water contents and biochemical compositions of M. coruscus in three age groups were determined from proliferation stage, growing stage, maturation stage, spawning stage to spent stage.The results show that (1) The changes of meat condition index and water contents are not significant(P>0.05)in same development stage, while the changes in different development stages are significant(P<0.05). The maximum values of meat condition index in three groups are 17.76%~19.21% in maturation stage, but the values of meat condition index are the lowest in spent stage, and the values in maturation stage are 3.15 times as high as those in spent stage; The maximum values of water contents in three groups are 93.29%~95.32% in spent stage, while those are the lowest in maturation stage, and the values of water contents in spent stage are 1.15 times as high as those in maturation stage. (2) The changes of crude proteins, crude lipids, ash contents and glycogen in different developmental stages are significant(P<0.05). The maximum values of crude proteins and crude lipids respectively are 72.01% and 13.52% in maturation stage. Furthermore, the maximum of ash contents is 7.59% in spent stage, and glycogen is 13.56% in spawning stage. The values of crude proteins and crude lipids are the lowest in spent stage and in proliferation stage respectively. The values of ash contents and glycogen are lowest in maturation stage. (3) In conclusion, changes of accumulation and consumption of crude proteins are anastomosed with changes of meat condition index. This study indicates that the meat condition index rises due to absorption and storage of energy by M. coruscus in gametogenesis, while it descends because of the release of gametes.

Key words: Mytilus coruscus, meat condition index, water contents, biochemical compositions, gonad development