This project aims at studying the connectivity and demographic stability of common sole populations (Solea solea) in the North Sea and adjacent waters. First, we will investigate the spatial and temporal connectivity between the major European spawning grounds and nursery areas of common sole. The origin of adults caught at the mixed feeding grounds will be determined and the relative importance of the different nurseries/spawning populations to the mixed stock will be estimated. A combination of both neutral genetic markers (mtDNA and microsatellite DNA) and ecological markers (elemental composition of fish otoliths) will be used. Secondly, DNA from historical fish otoliths (1955-1990) will be analyzed to examine the demographic stability of the North Sea sole stock and to investigate whether the fishery (mainly by beam trawl) has had an impact on the genetic diversity of the population. The project is funded by IWT-Vlaanderen.