The goal of this population genetic study is fundamental and twofold. First the genetic history of a freshwater fish species representative for the holarctic region is investigated. The genetic variation in a continental context will be mapped to infer the historical evolution of the burbot. If possible the genetic markers will be calibrated by using known absolute geological data. A second part of the study encompasses genetic structure on a regional scale. In this case more recent aspects of the distribution of burbot will be studied in order to iden- tify effective population size, colonisation patterns and gene flow. The burbot makes a very interesting study object from a fundamental point of view as it is the only freshwater species from the gadoids. It has a holarctic distribution, lives as a carnivore in slow running rivers and has a generation time of approxicately three years.