The French agriculture and fisheries ministry says that the mystery disease is killing between 40 and 90 per cent of the oysters in oyster beds - far higher than the normal mortality rate that has been seen in recent years.
The French Agriculture Minister Michel Barnier has called for as full investigation to look into the cause of the deaths.
The first test results have not shown the presence of any unique pathogen that could be causing the deaths and the agriculture minister said that the presence of know pathogens are not a risk to consumers.
The minister has called for extra vigilance to discover the cause of the deaths and he has called for a report on how the incident is going to effect oyster production.
The problem is affecting all the oyster producing areas of France but in particular the Thau salt water lake near Montpellier.
Mystery Ailment Killing French Oysters
FRANCE - The French shellfish industry has been hit by a mystery disease that is killing stocks of young oysters.