6 days ago
'Acoustic trauma' could have caused Mayo whale beaching
A True's beaked whale and her calf who became stranded and died in Co Mayo could have beached due to "acoustic trauma", according to the CEO of the Irish Whale and Dolphin Group.
Acoustic trauma can cause great harm to whales due to loud man-made sounds in the ocean, particularly when naval exercises make use of active sonar.
Speaking on RTÉ's Morning Ireland, Dr Simon Berrow, who is also a lecturer at Atlantic Technical University Galway, said the stranding in Kilcummin Back Strand on 27 July happened around the same time as similar incidents in the Netherlands and Orkney in Scotland.
"When you put them all together, it could just be a coincidence, or it could indicate that something has happened.
"Typically, when these deep-diving species live-strand, your first thought is it could be acoustic trauma," Dr Berrow said.
He added: "These species are deep divers. They'll go down to 1,000 or 2,000 metres on every dive so they're designed to dive deep routinely.
"And often they're getting washed up with signs of the bends, which is an incredibly unusual thing, so it tends to be attributed to acoustic trauma when the animal has surfaced too fast.
"This is generally associated with typically naval exercises because the navy - not the Irish navy – would use a thing called an 'active sonar' which is the same frequency as the whales use to communicate and they're incredibly sensitive to these frequencies.
"We're not saying that's the case but when you've an unusual event over a wide geographical range you kind of flag and think 'what's going on? Is this just a coincidence or a little bit indicative of something sinister going on'," Dr Berrow said.
According to Dr Berrow, the stranding of the two True's beaked whales was only the second confirmed sighting in Irish waters ever, and the 20th stranding of that species in total since 1899.
He said nothing at all could have been done to save the whales after they became stranded.
"The logistics of refloating these whales are quite challenging, you need people, you need people who are trained, it can be quite dangerous."
Dr Berrow added that while the calf refloated on its own, it was found dead a few days later.
"It probably died fairly quickly and that's probably a good thing because with the adult mother dying the calf would have starved to death," he said.
An investigation is under way to determine what happened to the whales.
However, Dr Berrow is unsure whether it will get to the bottom of what happened due to the complexity of conducting the post-mortem and a lack of expertise in Ireland.
