Recently, some evidence has been found for a separate population in the southern distribution area of European eel. This project examines whether this phenomenon also occurs within the Western European populations, and if it can be found on a more subtle manner. We will test whether the same structure can be found in glass and silver eel using phenotypic (number of vertebrae, age and condition index) and two genetic markers. For such case, highly variable genetic markers such as microsatellites are recommended. To seek for possible selective influences during and before freshwater stay (larval drift), selective markers i.e. allozymes will be used. A temporal genetic analysis of eel seems necessary for an accurate assessment of the genetic distribution across Europe and an improvement of management measures.