Type of infrastructure:
Location:
Country:
Netherlands
Targeted species or habitat:
Implementation period:
2020 - 2023
Implemented by:
Ørsted, Wageningen Marine Research, and the Rich North Sea
TRL:
6
Funding:
Ørsted and The Rich North Sea

Knowledge sharing

A report about the projects is available online M.J.C. Rozemeijer, B. Berges, F.A.G. Jacobs, E. van Onselen, C. Meeldijk (2024), ‘Habitat use, home-ranges and activity patterns of translocated European lobster Homarus Gammarus on artificial reefs as assessed by acoustic telemetry’,  and also further information is also available in the Rich North Sea toolbox.

Database Project

Development of biodiversity around artificial reefs

Objectives

To investigate the contributions of artificial reefs to marine biodiversity in the North Sea, specifically targeting Atlantic cod and European lobsters.


Short description

In 2020, Ørsted, in collaboration with Wageningen Marine Research and The Rich North Sea, installed cylindrical concrete structures of varying sizes at four sites within the Borssele I & II offshore wind farmBorssele I & II wind farm is located 23 km off the coast of Westkapelle. It comprises 94 turbines and a total combined installed capacity of 752 MW. in the Netherlands. At two of these sites, rocks were also added as scour protection, and two of the artificial reefs were placed on these rocky pads. The structures are designed to shelter Atlantic cod and other large fish species, as well as attract crustaceans such as the European lobster. Fishing is prohibited inside and around the offshore wind farms in the Netherlands, which improves the chances for the project to achieve its goals and enhance biodiversity in the area. Both Atlantic cod and European lobster have experienced significant decline in recent decades due to overfishing, climate change and habitat degradation. These species are crucial for maintaining the balance of the marine ecosystem in the area.

Ecological monitoring was conducted during the first two years of the project (2021-2022). The behaviour of cod and lobsters around the artificial reef was tracked by tagging them with acoustic transmitters and following their movements. Cod were caught in the area, tagged, and released back to the water, while the lobsters were brought from Ireland, tagged and released to the area. The results from the ecological monitoring indicate that cod were attracted to the artificial reefs,  showing high fidelity and residency, while lobsters left the area after a short period of time. The reasons for the lobsters’ low attachment have not yet been fully determined, but potential explanatory factors could be the effect of animal translocation (due to their strong homing sense), a lack of food on the young reefs, or shortage of suitable crevices.