The dramatic decline of large coastal fish species, including cod and whiting, has significantly impacted marine ecosystems along the Swedish west coast. The Ecosystem-based fish management in the 8-fjord area project aims to restore these stocks, with a particular focus on cod. A key challenge is understanding the origin of cod larvae found in the fjords of Bohuslän. It remains unclear whether these juveniles result from local spawning or are transported from other regions such as Öresund, the southern Kattegat, or the North Sea—an uncertainty that limits the ability to design targeted restoration strategies. This research project uses whole genome sequencing (WGS) of 280 juvenile cod sampled across fjord and reference areas to investigate population structure and larval connectivity. Genomic data will be processed and analyzed to identify genetic differentiation, assess the presence of distinct population units, and determine the likely origin of cod recruits in the fjords. In addition to the core cod analysis, the project includes exploratory genomic work on other ecologically or commercially important fish species in the region. The research integrates population genomics, bioinformatics, and statistical modelling to generate insights relevant to ecosystem-based management. The findings will inform evidence-based conservation planning and contribute to a broader understanding of genetic connectivity in coastal fish populations, supporting ongoing restoration efforts in the 8-fjord area and beyond.