Sound Effects

The National Oceanic and Atmospheric Administration believes it has finally found conclusive evidence about what causes whale beachings, and it has marine biologist Ken Balcomb, research director of the Washington-based Center for Whale Research, to thank for the discovery. On March 15 and 16, sixteen whales beached themselves on various islands in the Bahamas, several of them in front of Balcomb’s Abaco home. While most beached whales have been discovered too late for autopsies to be of any benefit, Balcomb acted quickly to preserve the corpses. Preliminary necropsies found hemorrhages in or around the whales’ ears consistent with the effects of a “distant explosion, or an intense acoustic event” that specialists said would have given the animals the equivalent of “a really bad headache.”

Turns out the Navy was conducting exercises in the area using low-frequency “active sonar” systems that transmit at about 235 decibels. A similar episode occurred in the Mediterranean in 1996 after NATO active sonar exercises there. Hardest hit in both episodes were reclusive, deep-diving beaked whales, including several of the Cuvier species which descends to depths of 6,000 feet. The Navy said it is cooperating in the investigation and that, if studies conclude that Navy sonar can cause trauma in whales, “the Navy will reassess its use of sonars.”