Dear MARMAM community, On behalf of my coauthors, I am pleased to share our new publication, “Impacts of large-scale maintenance of a floating offshore wind farm on noise levels and harbour porpoise activity” in ICES Journal of Marine Science.
Caitlin B Harris, Steven Benjamins, Nienke van Geel, Ellen White, Beth Scott, Benjamin J Williamson, Impacts of large-scale maintenance of a floating offshore wind farm on noise levels and harbour porpoise activity, ICES Journal of Marine Science, Volume 83, Issue 8, August 2026, fsag150, https://doi.org/10.1093/icesjms/fsag150 Abstract: For some floating offshore wind designs, turbines can be disconnected and towed to port for major component replacement, but the ecological effects of these operations remain unknown. This study investigates the relationship between underwater noise levels and harbour porpoise occurrence and potential foraging activity during the tow-to-port maintenance of turbines at Hywind Scotland. Passive acoustic click detectors were deployed along a gradient array from the wind farm, with broadband recorders positioned at two locations along the array. Sound pressure levels (derived from one-third octave bands spanning 25 Hz to 40 kHz) increased significantly during large-scale maintenance, particularly during towing and mooring work, with peaks up to 29 dB above routine operational averages. Concurrently, porpoise detections declined, particularly within 2 km of a turbine, with reductions of up to 33% at 600 m from the nearest turbine during periods of large-scale maintenance compared to routine operations. Detection rates increased once high-intensity activities ceased, suggesting effects were temporary. Potential foraging activity showed no consistent change, indicating that porpoises likely continued to forage when present. These findings provide the first evidence of ecological responses to tow-to-port maintenance at a floating wind farm and suggest that disturbance may be short-lived and spatially restricted. However, this may change as wind farm size increases, as maintenance operations are likely to involve more turbines and vessels, potentially extending the duration and spatial extent of disturbance. As floating offshore wind developments expand in size, continued monitoring will be essential to assess cumulative and longer-term impacts of maintenance activities and to support effective environmental management. Best wishes, Caitlin Harris
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