Royal Netherlands Institute for Sea Research


The Wadden Sea is a UNESCO world heritage site and renowned for being the most extensive intertidal mudflat system in the world. In the Swimway project, we will study conservation and restoration measures to help restore the fish community in the Dutch Wadden Sea.

Working on the recovery of fish stocks through a combination of research and restoration measures.

Funding and collaboration

The Swimway project is funded by Waddenfonds, the Ministry of LNV, Rijkswaterstaat and the three northern Dutch provinces. In this project, five PhD candidates collaborate and address different questions regarding Wadden Sea fish and nature management. Two of these PhD candidates are based at NIOZ. The research in this large collaborative project is conducted in close connection with Rijksuniversiteit Groningen, Wageningen Marine Research/Wageningen University, the Royal Netherlands Institute for Sea Research, the Waddenvereniging and Sportvisserij Nederland. Other collaborations involve a broad range of stakeholders in the Wadden Sea area, including NGO’s and fisheries organisations. 

Essential fish habitat in the Wadden Sea

Habitat use by Wadden Sea fish depends on local (a)biotic circumstances. Preserving or restoring essential fish habitats is of major importance for enhancing population persistence and growth. This sub-project within Swimway aims to develop generic spatially structured life-stage-based models for a quantitative description of fish' dependency to essential nursery habitats. As input for these models we use existing knowledge and new data acquired through lab experiments on abiotic requirements for different species and their life-stages. We particularly want to find out about the essential and optimal conditions for growth and survival in different life-stages. We will use hydrodynamic 3D models to visualize available habitat for focal fish species, according to the current situation and in future scenarios.

Tracking fish migration and habitat selection 

Over the last decades, fish populations in the Wadden Sea region have declined, especially of larger fish. The causes and consequences of these declines are unknown. This sub-project within Swimway studies the migration and habitat use of several large fish species using acoustic telemetry and data storage tagging. We use these spatiotemporal data for modelling habitat selection within the Wadden Sea and migration routes between rivers, the Wadden Sea and North Sea. By combining smaller scale habitat selection with large scale migration, we aim to understand the complete life-cycle of fish. These insights will be applied to improve management of fish populations that use the Dutch Wadden Sea.

Wadden tools

The Swimway project is part of the overarching ‘Wadden Tools’ project. Four projects fall under this umbrella, oriented around measures regarding underwater diversity, fish migration, migratory and breeding birds. These projects jointly aim to improve the management of the Wadden Sea, making it healthier and more bountiful. 

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Project information
Linked department:
Linked centre of expertise:
1 Jan 2020 - 31 Dec 2024
  • Sportvisserij Nederland
  • University of Groningen (RUG), The Netherlands
  • Waddenvereniging
  • Wageningen Marine Research
  • Wageningen University & Research Centre (WUR), The Netherlands

Meet the team

Bijleveld, Allert
Senior Scientist
Leeuwen van, Anieke
Senior Scientist
Dye, Bass
PhD student
Edwards, Jena
PhD student
Leeuwen van, Sonja
Senior Research Assistant