Harbor porpoises are among the most frequently bycaught cetaceans globally, and their sensitivity to acoustic disturbance makes industrial ocean noise a growing welfare concern.
Harbor porpoise bycatch deaths involve drowning in entangled gill nets, which for air-breathing mammals is a particularly distressing way to die. Porpoises caught in nets struggle desperately before losing consciousness, experiencing acute fear and physical trauma over several minutes. Acoustic disturbance from underwater construction and shipping causes both acute trauma in severe cases and chronic stress from the perpetual masking of echolocation. Porpoises that cannot reliably detect prey through their echolocation system face increased foraging effort and nutritional stress. Pingers are a proven intervention that reduces bycatch dramatically; their mandatory installation across high-risk fisheries would prevent tens of thousands of porpoise deaths annually at modest cost.