Blue and beaked whales affected by simulated naval sonar

Two recent studies have shown that blue and beaked whales' behaviour is disturbed by simulated naval sonar.

www.bbc.co.uk/news/science-environment-23115939

In two experiments, teams of researchers attached tracking and sound-recording tags to 17 blue whales and two beaked whales and then played simulated sonar sound through an underwater speaker and measured their responses.

Because previous beaked whale mass strandings and deaths have been linked to military exercises using 'mid-frequency' sonar, scientists were keen to know if the sound harmed the animals - these whales use sound to hunt (echolocation) as well as communicate. When the scientists played sonar during the experiment, both of the beaked whales stopped hunting and quickly swam away.

More surprisingly, in the other experiment, several of the blue whales (which don't use echolocation for hunting) responded to the sound. Whales feeding close to the surface showed almost no response but those diving for krill reacted very differently - for example, one animal stopped feeding and moved away from the sound source.

Although further research is necessary, this could have implications if naval exercises are frequently carried out in whale feeding hotspots - which they are, at present.