Anthropogenic noise in the ocean significantly disrupts cetacean communication, navigation, and behaviour, causing welfare harm to whales, dolphins, and porpoises.
Ocean noise pollution represents a pervasive welfare threat to cetaceans that is largely invisible compared to more tangible harms like entanglement and direct hunting. Cetaceans evolved in an acoustic environment where sound was their primary sensory modality — used for finding prey, maintaining social bonds, navigating, and communicating. Anthropogenic noise has transformed that environment. Shipping creates a chronic background roar that forces cetaceans to call louder — energetically costly and less effective — or gives up. Military sonar at sufficient intensity causes tissue damage, disorientation, and has been linked to mass strandings. Seismic surveys for oil and gas exploration create intense repeated impulses that cause acute welfare harm and habitat displacement. Mitigation measures including speed restrictions for shipping, sonar protocols, and seismic survey regulation can reduce harm.