Harbour porpoises are among the most acoustically sensitive marine mammals. Noise pollution from shipping and offshore construction causes significant welfare harm, while bycatch remains a leading mortality cause.
Harbour porpoises exist in increasingly noisy marine environments that compromise their ability to find food, communicate, and navigate. Acute noise events from pile-driving cause physical injury and displacement; chronic shipping noise masks echolocation signals needed for prey detection. Bycatch in static gillnets causes drowning — death by suffocation for an air-breathing mammal. Welfare interventions span multiple scales: acoustic deterrents (pingers) reduce gillnet bycatch, bubble curtains mitigate construction noise, and marine protected areas provide refuge from the most intense anthropogenic disturbance. Noise pollution regulations for the marine environment are improving but remain inadequate relative to the scale of welfare harm.