The authors are comparing the recruitment, the commercialised production, the cultivated biomasses of oysters Crassostrea gigas and Crassostrea angulata with the statistics of the meteorology (1885-1984). The temperature plays a role up on the date of spawning but partialy explains the lack of recruitment, which has less impact on the commercialised production than on the total biomass. The annual and seasonal characteristics of the precipitations and water temperatures do not show tight correlations with the variations of the production and of the biomass, for these cultivated populations in opposition with the sensitivity of the natural molluscan populations towards the climatic factors. |