Assessing the potential acoustic impact of floating offshore wind farms in the Central Mediterranean Sea

The Strait of Sicily, a vital marine passage with diverse fauna, is seeing a steep rise in the planning of offshore wind farm projects. This study assesses the acoustic impact of these wind farms on local marine species. Underwater propagation was modeled for three proposed floating wind farms using JASCO's Marine Operations Noise Model (MONM), which integrates a parabolic equation method for frequencies from 10 to 800 Hz and a beam-tracing model for 1 to 25 kHz. Propagation losses were calculated in one-third octave bands for ten source locations selected to represent the variability in bathymetry, and considering sound speed profiles for February and August. Sound levels from floating turbines were used to estimate exceedance ranges to known acoustic thresholds for marine species. Modeling indicated that sound levels could exceed temporary threshold shift and, for some species, permanent threshold shift criteria within a few tens of meters, but only if animals were to remain for 24 h at such small distances from a turbine. Behavioral disturbance thresholds for marine mammals were exceeded up to 68 km from the wind farms' boundaries. The study emphasizes considering species-specific sensitivities and ecological contexts in environmental impact assessments, recommending mitigation measures, such as the strategic placement of the turbines and continuous monitoring, to minimize adverse effects on local marine fauna, including marine mammals and turtles.