French oysters hit as mystery killer spreads

John Lichfield in the Independent (UK): A mysterious ailment is killing up to 80 per cent of adult oysters in shell fisheries around the French coast this summer, threatening an industry already weakened by a succession of crises. The bizarre weather – weeks of rain and cold followed by tropical temperatures – is officially blamed for the sudden death of scores of thousands of oysters in south-western France, Brittany and Normandy.

But producers fear that an unknown disease may be devastating oyster beds, stricken since 2008 by a virus which massacres baby oysters. French output has been slashed by a third in the past four years.

"Some people are having to ration their sales," said Olivier Laban, president of the association of oyster producers in the Bay of Arcachon, near Bordeaux. "We were already producing relatively few oysters because of the deaths of juveniles in past years. Prices are very high and cannot really go higher."

The sudden death of adult oysters, just before they go on sale, is even more calamitous. "It means three years of work wiped out overnight," said Laurent Champeau, president of the shellfish producers in the La Rochelle area. "Our margin for manoeuvre is already practically nothing."

The demise of 15 to 80 per cent of the two- to three-year-old oysters in Arcachon, Poitou-Charentes, northern Brittany and Normandy may be caused by the strange weather pattern this year, experts believe. Incessant rain from May to early July reduced the salt content of the water in the mud flats where the oysters are reared. The heat wave since mid-July has further weakened the shellfish, making them vulnerable to disease...

An aerial view of Arcachon in France, shot by Larrousiney, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license