Population genetics at the Wadden Sea station Sylt, part of the Alfred Wegener Institute, so far has focused on the clam Mya arenaria that is widely distributed on the Northern Hemisphere. Here, we can provide Cytb and ITS sequence data for several sampling locations from Brittany, France, up to the Barent Sea. A recent recolonisation of Europe by clams from the North American East Coast is assumed because of the very low sequence diversity of the European populations compared to American populations.Last year, a PhD study on population genetics of Cerastoderma edule and its parasites started. Until May 2007, we hope to get a geographic pattern of population structure of C. edule along the European shore shown by AFLP marker and COI sequences.