Hydropower plants can cause severe impacts on migrating fish, ranging from delays to physical damage leading to mortality. In the Life-project 'life4fish' the impact of six hydropower plants on downstream migrating silver European eels (Anguilla anguilla) are studied. The project contains three steps. In a first step, the reference status is studied by identifying the proportion of eels successfully passing the hydropower plants. Subsequently, three mitigation measures are tested: electrical fences and bubble curtains to deviate the eels from the turbines and the development of prediction models combined with turbine management. Finally the output of these measures will be integrated in the river stretch with the six hydropower plants and the overal efficacy will be tested.