Narwhals are deep-diving Arctic cetaceans extraordinarily sensitive to noise disturbance, relying on echolocation and social vocalisations in an environment increasingly affected by shipping, seismic surveys, and military sonar. Their physiological stress responses to noise rank among the most extreme recorded in any marine mammal.
The documented combination of cardiac stress response and erratic diving during vessel disturbance suggests narwhals experience acute fear and physiological crisis during noise exposure — not merely a mild startle. Repeated disturbance throughout a migration season or summer foraging period accumulates substantial welfare costs. Conservation management requires noise exclusion zones around narwhal summering aggregations, mandatory reduced speed for vessels transiting known narwhal habitat, and seasonal restrictions on seismic survey operations in Arctic waters during narwhal presence.