SOUND BITES: THE IMPACT OF BOAT NOISE ON FRESHWATER FISH
Noise pollution is rapidly becoming more prevalent on a global scale, yet it is one of the least studied anthropogenic disturbances. Sound has low attenuation in water where it travels five times further than it does in air. Such effects, coupled with the wide spatial and temporal distribution of anthropogenic noise, makes noise pollution a major concern for aquatic species that may lack refuge from this modern-day stressor. This thesis explores how boat noise impacts freshwater fish behaviour and is divided between a lab and field experiment. The lab experiment investigated how fathead minnow and brook char’s anti-predator responses to a looming stimulus was influenced by play-back tracks. Tracks were either recordings of boat noise from different distances (100, 250, 500 and 1000 m) or ambient lake recordings for our control. The field experiment looked at how yellow perch’s oxygen consumption, or stress level, was influenced by exposure to boat noise at different distances away from the running motor (same distances as lab experiment) compared to ambient lake noises. The results from our field experiment showed generally that the closer the boat was to the yellow perch, the more stressed the individual was. Furthermore, the majority of the fish exposed to boat noise at any distance used significantly more DO (dissolved oxygen) compared to individuals that were only exposed to ambient lake noises. In contrast, the lab experiment showed no evidence that boat noise influenced fathead minnow or brook char anti-predator responses; however, use of pre-recorded tracks in the laboratory may minimize effects. Future research needs to continue to understand how to use play-back tracks in a lab setting to create more ecologically relevant conditions. This research adds to the limited literature on how anthropogenic noise is influencing freshwater species.
Boat noise, freshwater, anthropogenic, noise pollution
Master of Science (M.Sc.)