In situ characterisation of pathogen dynamics during a Pacific oyster mortality syndrome episode

Significant mortality of Crassostrea gigas juveniles is observed systematically every year worldwide. Pacific Oyster Mortality Syndrome (POMS) caused by Ostreid Herpesvirus 1 (OsHV-1) infection leading to immune suppression, followed bacteraemia a consortium opportunistic bacteria. Using an in-situ approach and pelagic chambers, our aim in this study was identify pathogen dynamics oyster flesh the water column during course episode Mediterranean Thau lagoon (France). OsHV-1 concentrations increased before first clinical symptoms disease appeared, reached maximum moribund phase peak. The structure bacterial community associated with changed favour genera previously including Vibrio, Arcobacter, Psychrobium, Psychrilyobacter. During episode, releases bacteria were observed, succession, surrounding lanterns. These may spread within farms potentially impact other marine species, thereby reducing biodiversity shellfish farming areas.