In the autumn of 2018, in an area of 3 hectares, at water depths of around 20 metres, a structure of reef balls and cages containing adult oysters was installed at the Eneco Luchterduinen offshore wind farm. It is the first location where North Sea Foundation (Stichting De Noordzee) and Natuur & Milieu organisation are performing underwater ecology at offshore wind farms.
The first intermediate results show that there are opportunities for underwater nature development at offshore wind farms. However, the current reef structure has proven not te be optimal for the underwater conditions at the wind farm. During inspection, it turned out that large part of the artificial reefs had not survived winter. Some of the cages had sunk into the seabed. The remaining cages did show a encouraging survival rate of 80% and signs of growth at both dead and living oysters.
As a result, the nature organisations have therefore decided to postpone the research until the reef structure design has been optimised.
During the monitoring expedition the researchers also found that the oyster reefs attracted different underwater species such as crabs, clams, anemones, starfish, bib and squid eggs, underlining the potential of underwater nature growth at offshore wind farms.
The two nature organisations are working with Eneco Luchterduinen, Van Oord and ASN Bank. Waardenburg Consultants, SAS Consultancy, and Wageningen Marine Research are responsible for research into nature development in the wind farm. The demonstration project will contribute to providing a blueprint for underwater nature restoration at all offshore wind farms which can then be applied when constructing new installations.
Rich North Sea
The demonstration project is part of their joint project the Rich North Sea (De Rijke Noordzee) which aims to ensure that the growth of offshore wind farms goes hand in hand with nature enhancement. An 8.5 million euro in funding from the Dutch National Postcode Lottery, announced in February of this year, has made it possible for the organisations to expend the research to more offshore wind farms. Image: natuurenmilieu.nl