show Abstracthide AbstractGlobal change imposes environmental challenges on species, eventually resulting in (local) extinction or adaptation of populations to the new habitat conditions. Species with a wide distribution like the marine fish Zoarces viviparus have successfully colonized various habitats along temperature and salinity gradients, which might be indicative for the adaptive potential of this species to global change. This project aims to decipher the molecular mechanisms determining the ability of Z. viviparus to acclimatize and adapt to new environmental conditions, specifically increased water temperatures. Therefore, a high-quality chromosome level genome of Z. viviparus was assembled, integrating PacBio HiFi long-read sequencing data and Illumina Hi-C proximity ligation data, and annotated based on evidence derived from Illumina RNA-seq data, PacBio Iso-Seq data and protein databases. Given the importance of Z. viviparus as sentinel fish species for monitoring of marine health in northern Europe, the generated genome constitutes a valuable resource contribution not only for ecological and evolutionary research but also for applied environmental risk assessment studies. In this project, the genome serves as backbone for the analysis of RNA-sequencing data obtained from Z. viviparus individuals exposed to increased temperatures as well as as the analysis of transcriptomic and genomic Pool-seq data obtained from different Z. viviparus populations over the last 30 years. Through this, the direct physiological responses linked to heat stress as well as the transcriptomic and genomic signatures of environmental change can be identified, improving our understanding of the ecological and evolutionary processed shaping the ability of species to cope with global change.