Harbor porpoises are highly sensitive to underwater noise from shipping, sonar, and offshore construction, and chronic noise pollution disrupts their echolocation-based foraging and communication with serious welfare consequences.
Harbor porpoise welfare is acutely threatened by the expansion of anthropogenic underwater noise as offshore development and shipping traffic intensify. For animals whose primary sensory mode is acoustic, chronic noise pollution represents a fundamental welfare impairment comparable to blinding a visual species. Porpoises that cannot echolocate effectively cannot find food reliably, and those whose communication is masked cannot maintain the social bonds important for mothers and calves. Acute noise events like pile-driving cause temporary threshold shifts that leave porpoises temporarily deaf, unable to forage during the most critical recovery period after the noise event. Mitigation measures including bubble curtains, soft start protocols, and exclusion zones around construction sites reduce acute welfare harm but cannot address the cumulative burden of increased shipping traffic across major porpoise habitats.