Dépistage des sources de pollutions microbiologiques en Seudre amont et dans le bassin de Marennes Oléron

The oyster culture basin of Marennes - Oléron is characterized by the tastiness of its oysters and the good quality of its waters, and thus of its shellfish. On that account, the quasi-totality of the production areas are ranked A for non-burrowing shellfishes, thus confirming the privileged character of the basin. This microbiological and chemical quality contributing to the reputation of the basin's shellfish farms needs to be preserved. In this purpose, the Regional Shellfish Culture Section of Marennes - Oléron (SRC) approached the Ifremer in order to continue the monitoring of the microbiological quality carried out on different production areas susceptible to be affected by some bacteriological contaminations leading to a deterioration of the shellfishes' quality and consequently to a spoiling of the basin's image. The requested monitoring will complete the periodical microbiological analyses of the REMI network carried out by the Ifremer DEL laboratory of la Tremblade. In the framework of this network, 19 points are checked regularly in the basin on a monthly or quarterly basis. This study enables a more targeted monitoring of the bacteriological contamination sources listed during previous works conducted throughout the entire Marennes-Oléron basin. These sources (pluvial, canals flowing into the basin) which are often not connected directly to the shellfish production areas, could all be at the origin of faecal germ intakes and result in the contamination of shellfish resources.