Making migration possible – Afsluitdijk and the fish migration river

About the field trip

In 1932 the Afsluitdijk was completed. The primary purpose of the Afsluitdijk was to protect the Dutch interior from the unpredictable and often destructive forces of the sea. By closing off the so-called Zuiderzee from the Wadden Sea the Afsluitdijk effectively transformed the Zuiderzee into a freshwater lake. This lake is nowadays known as IJsselmeer. This freshwater reservoir provides a stable and controlled water source, which not only protects against flooding but also enables land reclamation and agricultural development. The iconic 32km long dike incorporates locks and sluices to control the water flow and maintain navigational access. Fish migration however was not an important topic back in the day and migration paths were closed off by the dike.  

The Fish Migration River is designed to provide a solution to this problem by opening the dike and recreating a more natural path for fish to migrate between salty and fresh water. It is a large, specially designed channel that runs parallel to the Afsluitdijk, connecting the Wadden Sea with the IJsselmeer. This encourages fish to navigate through the channel, overcoming the barrier that the Afsluitdijk presents. During this excursion, you will visit the Afsluitdijk and hear about different strategies and adaptations that are made to overcome the impact the dike has on the migration of different fish species. 

Themes covered

Wadden Sea, fish migration, fish-friendly pumping regime.

Important information 

Price for Afsluitdijk & Fish migration river field trip is €50.82 (inc. tax) and it includes guide, travel and lunch.  

Meeting place is the Groningen bus station at 8:30. Bus will leave at 9:00, be at the meeting place at least 15 minutes before departure. Planned return to Oosterpoort is by 19:00.  

Organised by


Aerial picture of the Afsluitdijk with the work on the fish migration river visible in the foreground and pumping station and sluices in the background (picture taken end of 2022)

Artist impression of the Fish migration river