In this project we will analyze WGS data to search for genetic differences between fish from populations in an artificially heated coastal bay (heated for 43 years) and fish from reference populations outside the heated area. Focus species is perch (Perca fluviatilis), and sequence data come both from freshly collected samples and from archived tissue samples spanning back to before the heating started, providing an excellent set-up to analyze the potential for warming to induce genetic differences. In addition, comparative analyses of WGS from fresh samples of roach (Rutilus rutilus) populations will be analysed in a similar set-up. All WGS come from individual samples, for which we also have trait data (body size and size of various organs, sex, growth, age, gonadal status), which we in a second step aim to associate to the results of the analyses of the sequence information. Exit strategy: The analyses are part of a PhD-project. The student is planned to defend in December 2024, so the analyses will be completed before the close-down of Rackham.