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Tuesday, March 15, 2011

Sonar soundwaves 'drive terrified whales to their death onshore'


Distressing: Researchers have found that sonar, wind turbines and gas and oil drilling can drive some beaked whales to come to the shore (file picture)

Soundwaves from underwater military sonar are far more distressing for whales than was previously thought and drives some terrified creatures to their death onshore, a new study has show.

Scientist say beaked whales may also react with terror to noise from offshore wind turbines and oil and gas exploration.

Two years ago Europe's largest military exercise held in Scottish waters was at the centre of a row when conservationists claimed two whales had been harmed by sonar.

The new study by researchers at St Andrews University looked at the effects of sounds on the behaviour of beaked whales in the Bahamas.

Researchers played sonar sounds to whales in the wild and recorded their reactions using electronic tags attached to their bodies.

Prof Ian Boyd, who led the study, said: 'We showed that the animals reacted to the sonar sound at much lower levels than had previously been assumed to be the case.

'We stopped exposing the animals to the sounds before there were any dangerous effects but it was clear that these whales moved quickly out of the way the sonars.

We now think that, in some unusual circumstances, they are just unable to get out of the way and this ends up with the animals stranding and dying.

Danger: Scientists say whales also react in terror to the noise made by offshore wind farms

'There was always a strong association between the death of these strange, little-known animals and naval exercises. We have now shown that this may well be the case.'

However, the researchers warned that other sounds could cause problems.
'There is a tendency to blame the Navy for every stranding event and that is ridiculous,' he said.

'We are now beginning to understand that some species of whales and dolphins appear to be much more robust to disturbance by sound than others.

'We also found that beaked whales responded in the same way to sounds other than sonars, included the calls of killer whales. It appears that they just don't like unusual sounds but the way in which sonars are used to hunt for submarines may mean that the whales are more vulnerable to that type of sound.'

source: dailymail


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