The Japan oyster: Crassostrea gigas have been imported on the french coasts in the seventies and from this time it adapted to this environment. Since, it became the main oyster producted in France. But ,since twenty years C. gigas presents an anormaly and important mortality eah year in the period of summer. The syndrome known as summer mortality, appears particulary in mid-june. This mortality can affected 50% of the culture. Many studies have brought elements in the comprehension of the condition of apparition of this mortalilities. Temperature seems to play an important rule with reproductive maturation. But also, the deep ofwater could be associated to this mass mortality. The study began in march 2003 and characterize more precisely the summer... |