Harbor porpoises are among the most acoustically sensitive marine mammals, making them particularly vulnerable to noise pollution and fishing gear entanglement in busy coastal waters.
Harbor porpoise welfare in European coastal waters illustrates how human economic activities concentrate welfare risks on non-target species. Gillnet fishing for flatfish, cod, and salmon provides economic value to fishing communities but kills tens of thousands of harbor porpoises annually as bycatch — a massive welfare externality that is largely invisible in fisheries management. The technical solution — pinger deployment on nets — is inexpensive, effective, and available, making the gap between regulatory requirement and actual compliance a welfare failure of implementation rather than technology. Acoustic disturbance from port construction, shipping intensification, and offshore wind development creates chronic noise environments that may affect harbor porpoise foraging success and physiological stress levels — welfare impacts that are harder to quantify than bycatch mortality but potentially significant at population scale.