Sole is a common fish in the North Sea and the English Channel. The question arises to what degree spawning populations show spatio-temporal stability, this is to which degree individuals are exchanged among spawning populations. To clarify this, multi-disciplinary research will be performed on all life stages with high-resolution genotyping, population dynamics and Lagrangian modelling. Due to the high degree of potential connectivity, a metapopulation model will be used to interpret the results.