Claires are special pens or enclosures where oysters are fattened in salt marshes in Marennes in Poitou-Charentes. With the Spring tides the estuarine waters flood into the pens and then recede. The water left behind becomes rich in blue-green algae which gives a slightly greenish tinge to the oysters grown threre. The resulting oysters, themselves called Claires, are considered a delicacy.
