Fish’s hearing is sensitive to the frequency of underwater sound generated by offshore wind turbines, ranging from tens to hundreds of hertz. Marine organisms living near these turbines experience prolonged exposure to underwater sound. In this study, we developed a system for measuring underwater sound pressure levels and analyzed the effects of low-frequency sound on the behavior of Pagrus major (red sea bream). Low-frequency sound (100 Hz pure tone) was emitted at 15-min intervals from an underwater speaker installed in the experimental tank. Prior to low-frequency sound emission, the fish were swimming in proximity to the speaker; however, during the initial low-frequency sound emission, the fish refrained from entering the area near the speaker. In subsequent experiments, no difference in swimming area with or without low-frequency sound was observed. Although temporary avoidance behavior was observed, these findings suggest that red sea bream gradually habituated to continuous underwater sound.
