Huîtres Marennes Oléron

Appearance & taste

The oysters are distinguished by a hard shell with mother-of-pearl on the inside and few encrusting organisms on the outside. They are sold live and unprocessed from 1 September to 31 May, in several varieties. “Fines de Claires” taste milder and less salty thanks to finishing; their filling index is between 7 and 10.5. “Spéciales de Claires” are selected for roundness, thickness and flesh; with a filling index from 10.5 they are fleshier and firmer and taste full-bodied. In the “Vertes” of both varieties the gills are coloured greenish, a sign of finishing in a pond with a lot of green algae.

“Pousse en Claire” are reared in the pond at very low density for at least four months. During this time the shell grows at the edge and forms characteristic points, the growth lines. With a filling index over 12 they are very fleshy and firm to the bite and have glossy, ivory-coloured flesh; they taste distinctly mineral, with a long finish.

Production

Only oysters from the open sea that were farmed on the French coast between the Spanish and Belgian borders may go into the ponds. Finishing and rearing take place in ponds in the area. These lie below the highest water levels at spring tide and are filled and emptied by gravity through their own hydraulic structure. They must be maintained regularly; every year they are drained and refilled (“varangage”), so that the microalgae on which the oysters feed develop and macroalgae do not take over.

On the walls of some ponds grows a diatom, Haslea ostrearia, which forms a blue pigment called “marennine”. When the oyster filters this water, its pale yellow gills turn greenish. The salt content in the ponds, which is usually lower, softens the salty taste. Packing takes place in the area on the day the oysters are taken out of the water, by specially trained staff: flat, with the curved half of the shell facing down, in wood-chip baskets that are tied up tightly.

Origin & history

The Île d’Oléron, about 30 km long and 10 km wide, protects the basin of around 400 km² from Atlantic low-pressure systems, surf and wind. In the south the Seudre and in the north the Charente bring fresh water. The rivers deposited sediments that formed an impermeable soil; the salt marsh covers about 3,000 ha. The area comprises 26 municipalities of the department of Charente-Maritime, including Marennes-Hiers-Brouage, La Tremblade, Le Château-d’Oléron and Saint-Pierre-d’Oléron.

According to the specification, the first ponds on the left bank of the Seudre were created in the 16th century. In 1698 the naval intendant in Rochefort wrote of Marennes: “The green oysters of Marennes are very well known.” In 1738 there were an estimated 7,000 ponds there, and in 1753 the term appears in the “Dictionnaire raisonné des sciences, des arts et des métiers”. Coste described the methods in detail in 1861. At the beginning of the 20th century, a third of French oyster production came from the basin. In the 20th century, animal diseases severely damaged first the European and then the Portuguese oyster, and finishing in ponds declined. From the 1990s the industry rebuilt the ponds and turned to the Pacific oyster.