Effects of Low-Frequency Continuous Sound from Offshore Wind Farms on Fish

Offshore wind farms (OWFs) are rapidly expanding around the world, as the demand for renewable energy is growing. In the operational phase, OWFs produce low-frequency continuous sound that overlaps with the frequency range of hearing and vocalizations of many fish species. While higher-level construction sound from OWFs has generally received the most attention, the number of studies investigating effects of operational sound on fish is quickly growing. Findings from the last 15 years are summarized, and potential effects of OWF sound include physiological changes that may affect cortisol synthesis, metabolism, growth and the immune system. Additionally, OWF sound may cause temporary threshold shift, masking, and behavioral responses, such as changes in swimming and feeding. Studies show varying results with different species and exposure treatments. There is a need for in situ experiments to better understand responses of free-swimming fish to OWF sound and to predict potential impacts on fish populations.