Ecological impacts of floating offshore wind on marine mammals and associated trophic interactions: current evidence and knowledge gaps

Floating offshore wind is expected to expand globally into further offshore, deeper and highly productive shelf seas to utilise increased and more consistent wind energy. Marine mammals represent mobile species that connect across regions and can indicate wider ecosystem changes. To date, only a handful of ecological impact studies have been conducted at floating offshore wind farms, due to the infancy of the technology and small numbers of operational sites. Understanding how floating offshore wind could alter ecosystem functions and impact species at individual and population levels will be essential to mitigate potential negative ecological impacts as the sector expands. Currently, numerous floating offshore wind sites are planned or already in development. Therefore, evaluating current knowledge and remaining knowledge gaps will benefit future projects in assessing ecological impacts and determining where additional research should be conducted. This review summarises the positive and negative ecological impacts that have been previously highlighted as potential impacts from floating offshore wind, focusing on marine mammals, whilst also considering prey and broader trophic interactions. Current studies at operational floating offshore wind sites are summarised and discussed in context of observed and/or anticipated impacts. Finally, key outstanding research areas are suggested in relation to each impact.