The lock weirs in Balgerhoeke and Schipdonk (Afleidingskanaal van de Leie, Belgium) form a barrier for eel, cyprinids, and other fish species. Research was conducted to determine the extent to which these barriers affect existing populations, whether fish can pass through, and whether passage facilities could be effective. Fykes were used to capture fish and was followed by species identification, length and weight determination and counting. Environmental data was obtained via waterinfo.be. Folderstructure data abiotiek: environmental data extern: data created outside the R project coordinaten: coordinaten_waterinfo: coordinates of measuring stations metingen: all used environmental stations vis: data of fish captured with fykes and an glass eel gutter extern: data created outside the R project ruw: dataset as provided by the data-responsible verwerkt_in_excel: data provided by the responsible researcher data balgerhoeke 2023: corrections made to original data maximale_vislengtes: maximal fish lengths per species media: pictures for report