During 23 years, 3 institutions sampled fish in the Belgian part of the river Meuse with two distincts methodologies. Data were provided by the survey of fish passages in fish ladders at Tailfer (upstream Namur) and Lixhe (downstream Liège) over the 1989-2011 period (Matondo & Ovidio 2016). Fish were collected daily in a trap placed in the upper pool of the ladder when the migration peaks occurred, and twice a week outside the major migration period. All the fish species were identified and species abundances were estimated without taking into account the juveniles and the youngs-of-the-year. Annual fish abundances were expressed as monthly averages. Data from Hastière, Andenne and Visé were provided by electrofishing from a boat along the banks in 1994, 2007, 2008, 2009 and 2010. Abundances were expressed as number of individuals by 100m² of river sampled.