Speaker: Professor Peter L. Tyack, University of St Andrews, Scotland.

ABSTRACT:

Beaked whales may be the least known family of large mammals, but they are known to strand and die during naval sonar exercises. To help understand how sonar causes this problem, we used acoustic recording tags to show that beaked whales dive to depths >1km for an hour or more to use echolocation to forage. By escalating the level of sounds played to tagged beaked whales, we could define the sound exposure that causes them to stop echolocating, disrupting their foraging behavior. These data have formed the basis for regulating training with sonar by some NATO navies. Research has enabled risk criteria that appear to protect beaked whales from sonar; now it is imperative for all navies that are committed to environmentally sustainable practices to use this research to develop policies to reduce the risk.