Professionals in the shellfish business have sounded the alarm over the future of the oyster. Climate change has already resulted in the French oyster harvest falling by one-third over the last five years, a meeting in Montpelier on the International Day of Shellfish Culture on Tuesday, August 28, was told.

One of the causes is a disease that has been affecting oysters for 10 years, Ostreid Herspesvirus. The herpes-like disease is particularly destructive for oysters in the first year of life. Fortunately, it is not contagious for humans.

Fabrice Permet, researcher at the French Research Institute for Exploitation of the Sea (Ifremer), said: “the warming of the sea is not a problem in itself for the oyster. It develops very well in water whose temperature goes up to 30 degrees. The warmer the water, the faster the oyster grows.” However, the disease is also encouraged by the warming of the water and global warming lengthens the periods of risk during which water reaches a temperature between 16 and 24 degrees.

Acidification is also a problem for shellfish, including oysters, the meeting heard. Oyster farmers in the south of France are the most affected by climatic changes. In the Thau lagoon, between Sète and Agde, the high temperatures recorded this summer and the lack of wind have led to more stagnant water and the slow death of living organisms.