Military Sonar and Cetacean Welfare

Military active sonar exercises have been linked to mass strandings and behavioural disruption in cetaceans worldwide, representing one of the most documented examples of human-caused acute suffering in wild marine mammals.

Key Facts

Mid-frequency active sonar (MFAS) used in naval exercises generates sound pressure levels that can reach 235 decibels at source
Beaked whales are disproportionately affected by sonar exercises — multiple mass strandings have coincided with naval activities
Gas emboli (decompression-sickness-like lesions) found in stranded whales are consistent with rapid ascent responses triggered by sonar
The US Navy agreed to significant sonar restrictions in Hawaiian waters after litigation, demonstrating that mitigation is operationally feasible
Cetaceans exposed to sonar may abandon critical feeding and breeding habitat for days to weeks after exercises
Some researchers estimate that thousands of beaked whales die annually from sonar-related causes, most undetected in deep water
Passive acoustic monitoring can detect the presence of cetaceans before sonar exercises, enabling avoidance measures

Welfare Considerations

The welfare harms caused by military sonar are severe and well-documented. Affected whales experience acute acoustic trauma, panic responses, and in the most serious cases, internal haemorrhage and death from decompression-like injuries as they ascend too rapidly to escape the noise. Mass strandings — where animals beach themselves in apparent distress — represent the visible tip of a much larger iceberg of sub-lethal harm including chronic stress, disrupted feeding, and habitat abandonment. These are animals with complex social structures, long-term bonds, and rich cognitive lives experiencing extreme suffering on a scale that warrants serious policy attention.

What You Can Do

Support organisations litigating for stronger marine mammal protections in military training areas
Advocate for mandatory passive acoustic monitoring and mitigation protocols before and during naval exercises
Contact your elected representatives to support legislation requiring naval forces to use available sonar alternatives where feasible
Support research into sonar technologies that are less harmful to marine mammals
Follow and share the work of organisations like NRDC and Cetacean Society International on ocean noise policy
Engage with ocean noise pollution as a priority issue alongside plastic pollution and climate change