Occurrence and seasonality of Vibrio aestuarianus in sediment and Crassostrea gigas haemolymph at two oyster farms in France

• Published in: Diseases of Aquatic Organisms
• Main Authors: Azandegbe, Afi, Garnier, Matthieu, Andrieux, Francoise, Kerouel, Roger, Philippon, Xavier, Nicolas, Jean-Louis
• Other Authors: Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Unité Biotechnologies et Ressources Marines (BRM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Unité Dynamiques des Écosystèmes Côtiers (DYNECO)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2010
• Subjects: [SDV]Life Sciences [q-bio]; [SDU]Sciences of the Universe [physics]; Crassostrea gigas; Pacific oyster
• Online Access: https://hal.science/hal-04498842; https://doi.org/10.3354/dao02253

Vibrio aestuarianus is frequently found in coastal areas and can infect and induce mortalities in the pacific oyster Crassostrea gigas. However, nothing is known about its distribution and seasonality in the estuarine environment, especially where oyster farming is practiced. Its occurrence was investigated in sediment and oyster haemolymph at 2 oyster farms in Brittany (France) over 2 yr during 2 periods, from June to September 2007 and from February to June 2008. Total heterotrophic bacteria (HB) were cultured on marine agar while total Vibrio spp. and V. aestuarianus were selectively numerated using thiosulfate citrate bile salts sucrose agar (TCBS agar) and the species-specific hybridisation method, respectively. PCR was performed to detect V. aestuarianus in sediment when it became unculturable. Both total Vibrio spp. and V. aestuarianus had a seasonal trend. The highest concentrations were recovered in the warmest months. Its abundance ranged from 10(2) to 4 x 10(5) CFU ml(-1) in haemolymph and from 10(3) to 1 x 10(4) CFU g(-1) in the sediment. Temperature was the main factor influencing the concentration of Vibrio spp. and V. aestuarianus in the sediment. Thus V aestuarianus might subsist during the cold seasons in the sediment, from which it can emerge when environmental conditions became favourable.