This study goes further previous investigations which highlited impacts of pesticides from the gene to the organism scales and sometimes in a multigenerational way. However, ecotoxicological studies often investigate single contaminants and use high concentrations that are not ecologically relevant. Moreover, multigenerationnal studies mostly investigate late exposure (during gametogenesis) whereas early developmental stages are windows of high susceptibility to environmental stressors. therefore, the PESTO project has two main questions: 1) What are the effects of an early exposure to environmentally relevant pesticide mixture in the Pacific oyster 2) Are those effects persistents across generations.