Correlating military sonar use with beaked whale mass strandings: What do the historical data show?

There have been several incidents in which U.S. Navy sonar operations at sea coincided in time and location with a mass stranding of marine mammals, particularly beaked whales. Although a conclusive cause-and-effect relationship has not been established, there is strong evidence and scientific concern that use of military sonar has resulted in beaked whale mass strandings. Most previous attempts to determine whether military sonar use and whale strandings are correlated have looked at mass stranding records of beaked whales and have singled out those instances in which military operations appear to coincide in time and location with a mass stranding event. In this study, historical data on beaked whale mass strandings and military exercises that were likely to include active sonar use were compiled, and statistical analyses were performed to determine the level of correlation between these events for four geographic regions. Strandings were significantly correlated with naval activity in the Mediterranean and Caribbean Seas, but not off the coasts of Japan and southern California.