The findings of a new government report into the causes of a mass stranding of pilot whales in the Kyle of Durness, Scotland in 2011 have revealed that military exercises in the area at the time were the probable cause of the deaths of 20 whales.

In July 2011, WDC staff assisted BDMLR in a long and difficult rescue where 44 pilot whales were successfully returned to the open ocean. Unfortunately, scores of the whales also died as a result of the stranding which occurred in an area where the military activities were taking place.

Post mortems carried out at the scene showed that, with the exception of one whale with a septic shoulder joint that was not debilitating, all were healthy. The Navy denied they were to blame for the deaths despite claims that large 1000lb explosives were used around the time of the stranding.

After the stranding, WDC formally requested a full investigation, which Defra (Department for Environment, Food and Rural Affairs) have now released. WDC also requested details from the MOD of the types of activities that were being conducting in the area at the time, and the size of the detonations that were taking place.

Noise pollution threatens whale and dolphin populations, interrupting their normal behaviour, driving them away from areas important to their survival, and at worst injuring or sometimes even causing their deaths. For whales and dolphins, ‘listening’ is as important as ‘seeing’ is for humans – they hunt, navigate, communicate using sound – yet there are still no international regulations regarding noise pollution in the world’s seas.

In 2013, a scientific analysis of the UK’s largest common dolphin stranding off the coast of Cornwall also stated that the most probable cause of the event were naval exercises in the area at the time – http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0060953

For a number of years WDC has been calling on the MOD to undertake a Strategic Environmental Assessment of all its activities that take place in its two offshore exercise areas in the UK – one of which is off the west coast of Scotland and includes the Cape Wrath range.

“On the Wednesday evening, some locals reported seeing whales close to shore”, recounts WDC policy lead, Sarah Dolman. “The following day, a number of high order explosions including 3 x 1000lb bombs were detonated. At noon on Friday the pilot whales were stranding in Durness and subsequently further detonations occurred. It would have been extraordinary if the series of detonations had not impacted this pilot whale pod.

“Strandings data provide vital information about the health of whales and dolphins and post mortem of whales that don’t survive is the only way we can pinpoint anthropogenic causes of health. Determining when intense noise has been a factor is incredibly tricky, but scientific techniques are being developed that will do exactly this in the future.

“One day we will look back and ask how it was that such intense noises as explosions were allowed to occur in productive waters such as these, without any monitoring or mitigation of whales and dolphins. “

WDC reiterates that such assessments are critical to ensure that the management and mitigation of all MOD activities are fit for purpose and can protect the UK’s valuable marine wildlife. In addition, the MOD should review its activities around Cape Wrath and ensure that management and mitigation are sufficient to ensure the safety of whales and dolphins in the area – such measures might include aerial surveys in the vicinity before clearance is given to detonate explosives, to ensure the area is clear of whales, dolphins and other marine wildlife.

