New Research Reveals Fish Communities in German Wind Farms

A new study led by the Johann Heinrich von Thünen-Institut has provided valuable insights into the fish communities inhabiting the Nordsee One wind farm, located in the southern German Bight. Conducted in collaboration with offshore wind farm operator Northland Power, this research marks the first comprehensive examination of the area’s fish species, revealing significant differences compared to other wind farm sites.

During a research expedition to the wind farm, scientists explored the specific fish species residing around the wind turbine foundations. Utilizing a combination of fishing techniques and underwater cameras, the team documented a diverse range of fish species. Vanessa Stelzenmüller, a leading researcher at the Thünen Institute, stated, “This allowed us to record a particularly wide range of fish species that reside in and around the foundations of the wind turbine.” The study highlights how many fish have adapted to the artificial structures, finding new habitats among the components and stone fills.

Previous studies conducted near Heligoland had established that the type of foundation and construction method influenced fish settlement. The latest findings indicate that the composition of fish communities at the Nordsee One wind farm varies notably from those observed in Heligoland. For instance, while researchers identified cod (Gadus morhua), mackerel (Scomber scombrus), and wood mackerel (Trachurus trachurus) in the Heligoland area, the southern wind farm was home to French cod (Trisopterus luscus) and dwarf cod (Trisopterus minutus), alongside similar mackerel species.

The study also uncovered the presence of the striped blenny (Parablennius gattorugine), typically associated with rocky seabeds, and various crab species including the common crab (Cancer pagurus) and velvet crab (Portunus puber). These findings support the theory that the artificial structures of wind farms, particularly the scour protection made from stones around the foundations, create a reef-like effect beneficial to marine life.

Despite these insights, the reasons for the differing fish communities between the southern and northern German Bight remain unclear. Researchers speculate that variations in water mass characteristics and even minor differences in the stone diameter used for scour protection may play a role in this phenomenon.

Till Frohloff, Managing Director of the Nordsee One wind farm, expressed the importance of supporting scientific research within the facility. “It was very important to us to actively support the scientific investigations in the wind farm. This is the only way we can gain reliable insights into how our plants influence the marine ecosystem,” he noted. Frohloff emphasized that the research results are invaluable for ensuring that future impacts on the ecosystem are minimal and sustainable, especially during the dismantling phase.

The study underscores that offshore wind farms not only contribute to energy security but also significantly influence marine ecosystems. Both scientists and wind farm operators agree that these ecological effects should be carefully considered in land development planning, including construction, operational extensions, and the eventual dismantling of offshore wind farms.

Further information on this research can be found on the Thünen Institute’s website, which explores the impact of offshore wind and other marine renewables on European fisheries.