Epigenetic modifications such as methylation marks can affect key performance traits in animals, including ones related to fertility. Nevertheless, limited information exists regarding the underlying epigenetic marks affecting reproductive success in fish. In the current project, we aim to identify methylation marks associated with fertility in fish using Arctic charr as our model organism. It is worth stating that the commonly observed highly variable reproductive success in captivity is a major bottleneck for Swedish Arctic charr farming. Overall, the suggested project will analyse high-throughput sequencing datasets that are generated under the FORMAS project EpiBreedCharr (https://www.slu.se/en/faculties/vh/research/forskningsprojekt/vilt-och-fisk/epibreedcharr--epigenetic-powered-breeding-in-arctic-charr/).