Artificial structures off the coast of Scheveningen can contribute to an increase in biodiversity. This was confirmed by a recent dive mission at the Offshore Test Site where The Rich North Sea rents a plot, located 12 kilometers off the coast of Scheveningen. In 2021, four underwater structures were installed here at a depth of 20 meters to monitor the development of species richness around them.

Increase in observed species

The research, conducted by divers and ecologists from Waardenburg Ecology and The Rich North Sea, shows that the number of observed species increased from 25 in 2021 to 39 in 2024. The results are promising, but additional research is needed to rule out other possible explanations for this increase – such as improved visibility. Underwater footage was captured and analyzed around the four structures. Plumose anemone and oaten pipes hydroid were found growing on the structures, while reef-building worms, mussels, and various predatory fish were observed in and around them. For the first time, conger eels and cod were also spotted near the structures.

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Credits: Klaudie Bartelink

Pearwood as a biodegradable structure

During the mission, part of the (T)REE(F) structure, which has biodegradable pearwood attached to it, was retrieved from the water for further inspection by NIOZ. This analysis will determine the stability of this type of wood and what organisms have started to grow in and on it. This will provide valuable insights into the suitability of pearwood as a naturally degradable substrate and the role it can play in future underwater structures.

Importance for future restoration efforts

The results are promising and demonstrate that artificial reefs can play a role in nature restoration and biodiversity enhancement in offshore wind farms. These structures provide habitat for various species and contribute to a healthier ecosystem in the North Sea. By continuing to monitor and learn, we can optimize these structures and thereby improve their effectiveness.

Learn more about this project in our Toolbox.