Blauwwind

Start 2020

Partners Blauwwind consortium, Van Oord, Bluestream offshore, Eurofins AquaSense

Our impact

Boosting oyster populations for a stronger sea

Flat oysters have nearly vanished from the Dutch North Sea, despite their vital role in marine ecosystems. Oyster reefs play a crucial role in marine environments, like filtering seawater, providing habitat for small fish, and attracting species like sharks, rays, and seals. This project explores whether oysters can reproduce and establish on shell and stone substrates around wind turbines. It also examines overall biodiversity in this newly built wind farm, assessing how species like soft coral adapt to the reef structures.

The Collaboration

Project partners

As the project’s key facilitator, Blauwwind Consortium granted access to their wind farm and arranged the necessary permits. Van Oord was responsible for designing and developing the oyster baskets used in the field, and Bluestream Offshore arranged the vessels needed to carry out the missions. Our scientific partner, Eurofins AquaSense, delivered reports on the monitoring results.

The research

To restore flat oysters in the North Sea, we need to know what helps them thrive in wind farms. In 2020, 2,400 oysters were placed in broodstock structures at Blauwwind to test reproduction and settlement. Researchers studied growth, habitat, and predator exposure to find the best conditions for future reefs that boost marine biodiversity.

Monitoring took place in 2020, 2021, 2023, and is planned for 2028. Researchers used ROV surveys for high-resolution imagery, eDNA analysis, and larvae sampling. Oyster tables were hoisted aboard for growth measurements, Bonamia testing, and spat settlement checks. Spat collectors were deployed and retrieved, while marine growth was assessed through scrape samples to track biodiversity changes.

Our role

The Rich North Sea executed Blauwwind’s vision for this project, translating their ecological ambitions into a practical installation and monitoring project. Blauwwind sought to design and build the Borssele III and IV wind farms in a way that supports a healthier sea, promoting responsible use and regeneration of the nature that once inhabited this area. To make this happen, The Rich North Sea assembled the team of partners and stakeholders, led the missions, and turned sustainable goals into action.

About the location

This project is located in the Borssele III & IV wind area, which is about 55 kilometres off the coast of Vlissingen. The turbines will supply a renewable energy equivalent to the consumption of 825,000 Dutch households. The Rich North Sea is working here with the Blauwwind consortium.

Results

Not just surviving, but thriving!

The oyster broodstock structures held up well, and the results are promising! Monitoring in 2021 and 2023 showed that 70% of the adult oysters survived, and many were ready to reproduce. Even better, young oysters were spotted both inside and outside the baskets, and oyster larvae were found in the water.

This means the oysters aren’t just surviving; they’re settling and spreading! These findings prove that offshore wind farms can support oyster restoration, but there’s still more to learn. By fine-tuning the conditions, we can create thriving oyster reefs that boost biodiversity and bring even more life to the North Sea.