The goal of this project is to study the climate-related genomic adaptations of Atlantic herring to understand how the species has responded to environmental fluctuations over the recent past (~1000 years), and predict its genomic vulnerability to future climate. For this, we will integrate genomic data from contemporary and ancient DNA samples, environmental data, and statistical modelling methods. We will analyze whole-genome sequence data of single and pooled contemporary samples collected for more than 70 locations throughout the north Atlantic Ocean and the Baltic Sea, covering the entire geographic range of the species. Moreover, we will analyze whole genome sequence data of about 40 archaeological bone samples from sites in Poland, Estonia, and Denmark with an estimated date of 800 to 1600 CE. An analysis of the magnitude of the mismatch of current genome-environment associations with past reconstructions and future climate projections (“genomic offset”), will allow us to estimate the genetic change required to track past, present, and future climates. With this project, we expect to identify genetic regions that have shown significant changes in allele frequencies between ancient and contemporary samples, and populations that might be more vulnerable to future climates. This knowledge will be crucial for understanding genetically-determined climate responses in marine pelagic fish, and for the protection of Atlantic herring, a species of major ecological, economical, and cultural importance.