The European eel (Anguilla anguilla) is an eel species that is critically endangered. Glass eels migrate from the Sargasso Sea towards Europe and spend most of their life in freshwater. After 5-20 years the eels start to mature and become "silver eels". These silver eel migrate downstream towards the sea to start their long spawning migration back to the Sargasso Sea. During this spawning migration, silver eels encounter several anthropogenic migration barriers. This project aims to gain insight in when, how and where silver eels pass these migration barriers at Lith and Linne in the river Meuse and whether this results in losses of silver eels.