The latest Schweinswalstudie des Bundesverbands Windenergie Offshore (BWO) (harbour porpoise study) indicates that offshore wind farms apparently represent attractive refuges for harbour porpoises (Phocoena phocoena). The figures point to potential reef and refuge effects. A further result of the study is that the harbour porpoise populations in the German North Sea remain largely stable.
Within the wind farms, approximately 10 per cent more harbour porpoise detections were registered using hydrophones compared to the surrounding area up to 2.5 kilometres outside the offshore wind farms. The researchers attribute this to a combination of fisheries exclusion and reef effects. Foundations of offshore wind turbines form reefs that attract fish. These fish populations can develop undisturbed, as fishing is prohibited between the wind turbines as a safety precaution for critical infrastructure. Meanwhile, maintenance vessels operating within the wind farms apparently deter the harbour porpoises only minimally.
Generalised assumptions that offshore wind farms contradict species conservation and invariably have negative impacts on marine mammals are inaccurate - a precise assessment is required. Offshore wind energy and species conservation can be reconciled with careful planning – a significant finding in view of the necessary expansion targets for renewable energy generation in Germany and Europe.
Humans are not inherently detrimental to nature - they must simply respect the interconnections of ecosystems and plan sustainably.
Source: "Harbour porpoise trends and offshore wind farm effects in the German Bight, North Sea. Analysis of CPOD data", Julika Voß et al., May 2025, https://bwo-offshorewind.de/wp-content/uploads/2025/05/BWO_Studie-Harbour-porpoise-trends-and-offshore-wind-farm-effects-in-the-German-Bight-North-Sea.pdf
* ElasmOcean founding member Marika Schultz contributed to the study as a marine biologist for IBL Umweltplanung GmbH
