Abnormal mortality of triploid adult Pacific oysters: Is there a correlation with high gametogenesis in Normandy, France?

• Published in: Aquaculture
• Main Authors: Houssin, Maryline, Trancart, Suzanne, Denéchère, Lucie, Oden, Elise, Adeline, Beatrice, Lepoitevin, Mélanie, Pitel, Pierre-Hugues
• Other Authors: LABÉO, Pôle d’analyses et de recherche de Normandie (LABÉO), Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: crassostrea gigas; Triploi; Gametogenesis; Mortality; [SDV]Life Sciences [q-bio]; Pacific; Crassostrea gigas
• Online Access: https://hal-normandie-univ.archives-ouvertes.fr/hal-03400414; https://hal-normandie-univ.archives-ouvertes.fr/hal-03400414/document; https://hal-normandie-univ.archives-ouvertes.fr/hal-03400414/file/S0044848618320015.pdf; https://doi.org/10.1016/j.aquaculture.2019.02.043

International audience Summer mortalities of the adult Pacific oysters Crassostrea gigas are an important economic concern. In 2015 and 2016, the mortality of hatchery origin spat comprising 4 diploid batches and 9 triploid batches as well as 12 batches of wild caught diploids was followed at 3 sites in Normandy. Abnormal mortalities (> 20%) were observed at one site only and were significantly higher in triploid animals (P < .05). Triploid oysters are believed to be partially sterile but a high level of gametogenesis was observed in all monitored triploid batches. In 2015, preliminary results revealed that triploid oysters underwent strong gametogenesis with mature gametes (stage 3) and 50% of them were non-perturbed (i.e. named alpha). In 2016, 42% of triploid oysters were alpha. This study revealed that triploid oyster maturation occurred in September, which corresponded to the time of high mortalities in Normandy.