Cuvier's beaked whale
Cuvier's beaked whale seems to have a bad reaction to sonar. Strandings and beachings often occur near naval bases where sonar may have been in use. Cuvier's beaked whale has been observed in Hawaii avoiding diving for food or avoiding an area where sonar is in use. A higher incidence of strandings has been recorded in noisy seas such as the Mediterranean and multiple mass strandings have occurred following operations by the Spanish Navy in the Canary Islands. In 2019, a review of evidence on the mass strandings of beaked whales linked to naval exercises where sonar was used concluded the effects of mid-frequency active sonar are strongest on Cuvier's beaked whales but vary among individuals or populations, and the strength of the whales' response may depend on whether the individuals had prior exposure to sonar. The report considered the most plausible explanation of the symptoms of decompression sickness such as gas embolism found in stranded whales to be the whales' response to sonar. It noted no more mass strandings had occurred in the Canary Islands once naval exercises using sonar were banned there, and recommended the ban be extended to other areas such as the Mediterranean, where mass strandings continue to occur.