Renewable Energy and Fish Deterrence: Using High Frequency Sound to Alter Alewife Behavior Around a Hydropower Intake

Renewable energy plays a key role in meeting global energy demands amidst the climate crisis; however, their impacts on fish in the surrounding waters remain a concern. Hydropower is an effective, established source of renewable energy; however, there is concern for entrainment and impingement at intakes. Acoustic deterrents offer a promising nonphysical method of deterring nearby fish, utilizing sound to alter fish behavior and prevent impingement at these intakes. The pilot study was conducted to determine the behavioral responses of alewives when presented with high frequency sound (122–128 kHz at 172 Db re 1 μPa), to evaluate the efficacy of sound deterrents around a hydropower generating site in Tusket, Nova Scotia. Sonar imaging was used to track fish movements before and after sound exposure, with results showing a significant decrease in fish presence, measured by mean pixel density and pixel standard deviation. Given the ecological significance of alewives and their vulnerability to hydropower-related mortality, these findings support the potential for acoustic deterrents to protect fish at this location, which is of particular importance during their migration season. Further studies are necessary to assess potential habituation to sound, as well as to evaluate the efficacy of integrating acoustic methods with other deterrent technologies.