Thesis: Radioactive releases from nuclear accidents induce chronic exposure of organisms in the environment. Populations are exposed over several generations, which can lead to deleterious effects. In the context of ecological risk assessment (ERA), studies on multigenerational effects are of growing interest. However, multigenerational studies after exposure to ionizing radiation (IR) are rare. This thesis project therefore concerns the assessment of reprotoxic effects and their transmission after gamma irradiation in Danio rerio. F0 adult fish were irradiated at different dose rates. The progeny (F1) is then placed either in a situation of continuous irradiation or in a control condition (recovery) until the next generation. This work allows to observe early mortality, malformations and masculinization of the F1 generation. A transcriptomic analysis reveals that maternal transcripts, necessary for embryonic development are altered. The contribution of epigenetic mechanisms in the transmission of information between generations has been assessed. Promotor methylation of key genes of sex determination in the F0 could explain F1 masculinization. This work highlights the involvement of parents in the effects observed in offspring. This project assess the effects of IR at different biological scales and to provide new knowledge for ERA. Finally, these results permit to propose a model of AOP for reprotoxic and transmissible effects after gamma irradiation