Wild oysters are no longer as abundant on France’s Atlantic coast as they once were and in fact the supply of them has effectively more or less become exhausted. In the 21st-century, virtually all the oysters eaten in France are farmed and approximately half of them are raised in the Marennes Oléron region where the River Seudre feeds freshwater into the flat shallow basins in the process keeping the saline level low – the best environment for cultivating oysters.
The life-cycle of an oyster is not a quick process. It begins with the oysters producing millions of eggs. After fertilisation the larvae attach themselves to supports which can easily be moved into ‘parks’which are underwater most of the time but become exposed at low tide.
At age 18 to 24 months, the oysters are moved to metal cages or often nowadays plastic boxes where they are regularly gently agitated causing them to grow round in shape. In the fourth year, the oysters are moved from the parks into ‘claires’ (shallow ponds connected to the sea by gullies) where they will be fattened up. The condensed mix of algae present in these claires gives the oysters the green colour found most desirable by gourmet chefs in high-class Parisien restaurants. The final stage before the oysters are sent to market is to purge them by putting them in basins of pure water.
Although oysters can be found in six other regions of France including the Mediterranean and Brittany, the oysters from Marennes-Oléron are particularly sought after.