Temporary hearing loss induced by impulsive pile driving in a particle-motion-sensitive fish, the summer flounder ( Paralichthys dentatus )

There is substantial concern that anthropogenic sounds, including high-amplitude, impulsive pile driving from offshore construction, may impact the hearing sensitivity of marine fauna. Despite their abundance and ecological relevance, data on auditory threshold shifts in fishes remain scarce, particularly for species lacking swim bladders that rely on particle motion for hearing. This study evaluated the potential for noise-induced hearing impairment in a particle motion-reliant fish after in situ pile driving exposure, using the flounder, an economically important benthic flatfish inhabiting North Atlantic regions with frequent offshore construction activities. Auditory evoked potential methods were used to (1) establish the flounder audiogram and (2) measure auditory thresholds at 170 Hz before and after pile-driving exposure. Flounder hearing was most sensitive at 100 Hz, overlapping with high-amplitude, low-frequency pile driving noise. Following exposures (15 min and 3 h duration, 184–187 SELcum dB re 1 μPa2·s), flounders exhibited temporary threshold shifts (3–7 dB) that persisted for at least 24 h. Such hearing loss can impair detection of ecologically important cues. Exposure levels were comparable to those at kilometer-scale distances from offshore wind construction, suggesting unexpected susceptibility to temporary threshold shift and a relatively large range of auditory impact for particle motion sensitive fish.