Short-Term Passive Acoustic Monitoring Indicates Associations Between Fish Vocal Activity and Offshore Wind Farm Noise

Abstract

The rapid expansion of offshore wind farms (OWFs) is reshaping coastal soundscapes through operational turbine noise, while the acoustic responses of soniferous fishes within operational wind-farm areas remain difficult to assess using conventional fishery surveys. In this study, passive acoustic monitoring (PAM) was deployed within the Yangjiang Offshore Wind Farm to examine short-term associations among underwater sound fields, turbine spatial layout, a turbine startup event, and putative fish-call activity. Fish-call detections were lower along the transect with 550 m turbine spacing than along the 1300 m transect, coinciding with higher measured sound pressure levels in the 550 m spacing layout. Acoustic activity in the central zone of the 1300 m array was 6.46 times higher than that of the 550 m layout, suggesting that lower-noise areas within wind farms may provide favorable acoustic conditions for detectable fish-calling activity. During a turbine startup event, fish-call detection rates temporarily decreased during the transient increase in sound pressure level and subsequently recovered as the underwater noise returned toward baseline conditions. These patterns indicate that PAM can capture short-term soundscape-associated variation in fish-calling activity or call detectability. We further propose a conceptual trade-off framework in which foundation-associated habitat benefits and operational noise may jointly shape the acoustic space use of soniferous fishes in OWFs.