The free migration of fish is obstructed.

Migratory fish need fresh and salt water for their lifecycle, but due to dikes and dams like the Afsluitdike it is nearly impossible for the fish to migrate. This is the main reason migratory fish are not doing very well.

The fish migration river is a opening in the Afsluitdijk that can be used by fish to migrate between the Waddenzee and the IJsselmeer. At the Waddenzee side of the opening a connection is made with the existing discharge bay, at the IJsselmeer side a river is made. To prevent salt water to flow into the IJsselmeer, a lock is placed.

• Migratory fish can more easily reproduce.
• A larger biodiversity of migratory fish will appear due to the return of species and the inflow of tidal migrants to the IJsselmeer.