| The variability in reproductive cycle of Pacific oyster, Crassostrea gigas, was evaluated in situ (Bay of Veys, BOV and Marennes-Oléron bay, MOB) and in hatchery culture conditions. Two trophic levels were tested over one year: high food level (HFL) and low food level (LFL). We observed that the phytoplanktonic concentration (chlorophyll a) was the principal factor that influenced gametogenesis intensity and duration. The oysters reared within a high trophic ration (BOV and HFL) shown a hyper-gonad development. However, the spawning efficiency was reduced and partial. Therefore, the resorption period was prolonged until winter. Meanwhile, the oysters reared in a low trophic ration (MOB and LFL) produced a normal gonad with a total spawning in summer and... |
