Fish have the natural behaviour to move across various aquatic ecosystems and for some species this is of vital importance. Migration is often a seasonal phenomenon which occurs in order to move between habitats, such as winter refuges-, foraging- and spawning or nursery habitats, also escaping unfavourable environmental conditions, expanding habitat, (re)populating new habitats and exchange between subpopulations. The Afsluitdijk in the Netherlands has been recognized as a bottleneck (obstacle) of major importance for fish migration, due to e.g. changes in natural salinity gradients and tidal regime as well as generated high water velocities, leading to short migration windows. Several ´fish friendly` management measures within the Afsluitdijk have been in operation, but most of them are not ideal. A large fish passage, the Fish Migration River (FMR) has been conceptualized at Kornwerderzand, which can provide opportunities for migratory fish to reach the IJsselmeer. In order to provide the FMR with the best possible design according to the ecology of occurring fish species, the Dienst Landelijk Gebied and the “De Nieuwe Afsluitdijk” (DNA) acquired a full assessment of the current situation at Kornwerderzand. This report provides insight in abundance and spatial distribution of 15 migratory fish species in fresh-salt transitions at the Kornwerderzand area in relation to tidal regimes, discharge events, discharge volume and temperature. Lift netsampling with the simultaneous application of the DIDSON (Dual frequency IDentification SONar; ultrasound underwater camera) camera was carried out to gain insight in the spatial and distribution of fish, combined with an enhanced fyke net sampling in and around the discharge basin at Kornwerderzand, carried out to evaluate the abundance.