ReefCreate-XL
Due to human activities, diseases, and climate change, natural reefs in the North Sea have largely disappeared from the seabed. As a result, biodiversity is under serious pressure. Reefs are a cornerstone of marine ecosystems: they provide food, shelter, and habitat for marine life. That is why this project aims to strengthen nature in the North Sea.
The Project
What Are We Doing?
Ten organizations are jointly investigating which reef structures are suitable for large-scale application to enhance marine life in the North Sea. The research takes place in the Frisian Front nature area, north of the Wadden Islands, where the structures will be deployed at sea. “Learning by doing” is central: in practice, it will be tested what works and what does not.
For years, various parties have been working on reef restoration using different methods. These include cultivating healthy oysters, using discarded fruit trees as a base for reef structures, and the innovative “remote setting” method. ReefCreate-XL brings these techniques together and builds on existing knowledge and experience.
The Reef Structures
The first step is optimizing the structures. After that, they will be placed in the sea and monitored. The following types of structures will be tested:
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Broodstock Structures: 240 structures stocked with 20,000 one-year-old oysters, serving as a starting point for further reef development.
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Spat on Substrate: 8 million juvenile oysters attached to substrates such as stones or clay bricks, helping to build a self-sustaining reef over time.
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Shell Feeders: Biodegradable ropes carrying mussels, providing shell material on which reef-building organisms such as certain worms can settle.
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TreeReefs: Discarded fruit trees placed on the seabed, quickly attracting marine life and providing a long-term habitat for reef-forming species.
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Reef Restoration Box (ReReBox): An experimental setup containing various structures, used to investigate biodiversity development and assess a site’s suitability for reef restoration.
Timeline
This four-year project involves deploying a variety of reef restoration structures at the Frisian Front, a protected marine area north of the Wadden Islands. The project’s central principle is “learning by doing”: testing in the field what works and what doesn’t.
2026: Reef structures are designed and tested. Monitoring parameters and techniques are defined.
2027: Assembly and deployment of reef structures and monitoring instruments at the Frisian Front.
2027-2029: Intensive monitoring to assess how the structures develop over time.
Project Update
Early Monitoring Shows Strong Oyster-spat Settlement
This summer, the ReefCreate-XL team carried out a monitoring campaign to assess how many European flat oyster larvae successfully settled on the broodstock structures. Different structure designs, substrates, and treatments are being tested.
During this monitoring round, 36 structures were examined in detail. Spat settlement has been highly successful. An average of 695 oysters per structure were counted. The largest spat had already grown to around one centimeter and were clearly visible to the naked eye.
Over the coming months, their development will be further tracked through photo monitoring. The aim is to deploy 20,000 one-year-old European flat oysters – around 80 oysters per structure – in 2027.
Partners
Eleven organizations are collaborating on the Reef Restoration-XL project: het Nederlands Instituut voor Onderzoek der Zee (NIOZ), Wageningen Marine Research, Waardenburg Ecology, Van Oord Ocean Health, EcoShape, The Rich North Sea, Naturalis Biodiversity Center, TU Delft, Stichting Zeeschelp, ARK Rewilding Nederland en Stichting Doggerland. Funding is provided with support from the European Union (Next Generation EU).
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