Northern bottlenose whale behaviour disrupted by sonar, say researchers

Study finds mammals will stop feeding, swim away or dive to great depths

Naval sonar can severely disrupt the behaviour of northern bottlenose whales over distances never previously tested, according to new research.

An international team, led by St Andrews and Iceland universities, used sensors attached to the whales and deep-ocean acoustic listening devices.

They found military sonar sounds caused the animals to stop feeding, swim away from the source of the noise and go into a deep dive.

The new study, published yesterday in Proceedings Of The Royal Society B, was led by St Andrews professor Patrick Miller and Dr Paul Wensveen of Iceland University, and involved a large team of scientists and engineers as part of the 3S (Sea Mammals, Sonar, Safety) international research project.

Prof Miller said: “All tagged whales stopped feeding, and individuals started swimming away from the exposure site for several hours when a certain sound level was reached, regardless of their proximity to the source – up to 28km away.

“One of the whales immediately responded by diving to a depth of 1.6km that lasted 130 minutes.

“We used a sound source that is smaller than a typical operational naval sonar, so the concern is that the distances at which animals respond in the wild to real navy sonars may be significantly greater.”

Research on elusive beaked whales, which include the northern bottlenose whale, has intensified following a number of unusual mass strandings in Iceland, Scotland, Ireland and Norway.

The animals inhabit areas that are frequently used by navies for sonar training and testing.

Tests were conducted near Jan Mayen, an island north of Iceland, in an area which still has little noise pollution.

Picture: Christian Harboe-Hansen. Tests were conducted near Jan Mayen, an island north of Iceland.