Military sonar has been implicated in mass stranding events of deep-diving cetaceans. Understanding this welfare harm informs policy on naval exercises and whale protection.
Sonar-related whale injuries cause acute welfare harm that may persist for days before death. Beaked whales exposed to sonar show panic responses — rapid ascent to the surface causing nitrogen embolism similar to decompression sickness. Internal hemorrhage around ears and in fatty deposits causes severe pain. Stranded animals from sonar events often show fresh hemorrhages on necropsy. The intelligence and social complexity of sperm whales — with their clan-based cultures and complex communication — gives their welfare particular moral weight. Restricting military sonar exercises in high-use whale habitat represents a direct welfare intervention.