Annual dynamics of glycogen, lipids, and proteins during the reproductive cycle of the surf clamMactra veneriformisfrom the north coast of Shandong Peninsular, China

The dynamics of Mactra veneriformis nutrient storage and exploitation during its reproductive cycle was studied in relation to environmental conditions from April 2007 to March 2008 on the north coast of Shandong Peninsula (China). Separate biochemical analyses of the mantle, adductor muscle, foot, and gonad-visceral mass in each sex were undertaken. Gonads of males and females developed concurrently and gametogenesis began in the month of December (early winter). Spawning started in July and appeared to continue until August and September when the water temperature was over 20°C and food was abundant. The majority of individuals were resorbing their gonad, or alternatively in a period of gonadal inactivity, in October and November. Utilization of glycogen took place during the spawning period, whereas protein was biosynthesized as the mature gametes formed. The glycogen value increased during the resting stage (autumn–winter). The reproductive pattern exhibited by M. veneriformis based on the storage of reserves during the late resting stage, and the gonad maturation period, seems to be conservative and opportunistic. The information on M. veneriformis reproductive strategy presented in this context is important for obtaining good-quality larvae and promoting successful restocking actions in the aquaculture management.