Exclusion of Adult Alewife, Alosa pseudoharengus Using Low-Frequency Sound for Application at Water Intakes

Experiments to test the effectiveness of low-frequency, high-intensity sound in excluding alewife, Alosa pseudoharengus, from an experimental net structure were conducted on Lake Ontario near Pickering, Ont. Sound was generated by modified seismic devices called pneumatic poppers. The number of alewife entering the experimental structure was reduced by 71–99% when the poppers were operating. Sonar evidence from one test suggested that another species which was not caught in the collection nets was less influenced by the acoustic deterrent. The results suggest that low-frequency, high-intensity sound may be effective in reducing losses of adult alewife at water intakes.