Abstract
Offshore wind farms (OWFs) are integral to the global shift towards renewable energy, yet they introduce complex challenges for marine biodiversity. OWF development affects a range of species — including fish, invertebrates, seabirds and marine mammals — through noise pollution, habitat alteration, physical barriers and potential entanglement. Conversely, turbine structures can act as artificial reefs and fish refuges, enhancing local biodiversity. This Review synthesizes current knowledge of OWF impacts across their life cycle — from construction to decommissioning — highlighting both direct and indirect ecological effects, including food web changes and displacement of fisheries. The Review discusses assessment, monitoring and mitigation strategies, and emphasizes the need for more coordinated international approaches, particularly in the areas of data sharing, cumulative impact assessments and long-term ecological monitoring. Differences in governance, regulation, data collection and mitigation strategies across countries or regions lead to varying biodiversity outcomes at OWFs. We outline priority steps that could be taken to improve assessment and monitoring across regional and international scales, including the use of emerging technologies, adaptive management, the development of more sophisticated models and decision-support tools, and the establishment of regionally tailored ecosystem monitoring programmes to better understand the impacts of OWF energy developments on biodiversity.