Impact of pollutants and climate change stressors on reproduction capacity and embryo- larval development of the oyster Crassostrea gigas in the Arcachon bay

• Main Author: Gamain, Perrine
• Other Authors: Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux, Patrice Gonzalez
• Format: Thesis
• Language: French
• Published: HAL CCSD 2016
• Subjects: Comportemental analysis; Salinity; Climate change; Crassostrea gigas; Embryo-larval test; Pollutants; Test embryo-larvaire; Polluants; Changement climatique; Température; Salinité; Analyse comportementale; envir; demo; Pacific; Pacific oyster
• Online Access: https://tel.archives-ouvertes.fr/tel-01306578/file/GAMAIN_PERRINE_2016_CORR.pdf; https://tel.archives-ouvertes.fr/tel-01306578

The Pacific oyster represents an important part of the aquaculture production, with 555 913 tons produced in 2013. France is the fourth world producer of oysters and Crassostrea gigas is the principal cultivated species in the Arcachon bay. However, in recent years, problems of recruitment, capture and mortality of juvenile or adult oysters occurred. The increased frequency of these events can be indicative of changes in the global quality of the Arcachon bay. In this context of crisis, this work has been focused on the impact of two pollutants, copper and S-metolachlor, mostly found in the waters of the Arcachon bay, on D-larvae embryo-larval development of the Pacific oyster (24h post -fecundation). In a context of global climate change, a multifactorial approach was adopted to study the combined effects of pollutants and increase temperature or salinity changes that could affect the development and survival of embryos and larvae during reproduction season. First, the embryo-toxic effects of copper or S-metolachlor coupled to salinity or different temperatures were studied with oysters from hatchery. For this, the embryo-larval test was used, and its application limits specified. Secondly, the effects of pollutants combined or not to environmental temperature and salinity were analyzed on embryos from wild or cultivated oysters harvested directly on different sites of the Arcachon bay. The percentage of abnormalities and the differential expression levels of target genes were determined in larvae while the Cu and S-metolachlor bioaccumulation and the percentage of gonadal occupation were measured in genitors. These results were then compared to determine the ability of oyster from hatchery to represent an interesting alternative model to indigenous oysters. With the objective to study the impacts of climate change, somewhat more extreme conditions were tested, namely temperatures of 26 ° C, lower salinity of 24 u.s.i and higher concentrations of pollutants compared to current conditions in the lagoon. A ...