Marine animal experts have confirmed two porpoises found dead off the Mearns coast were killed by dolphins.
A busy weekend of strange mammal behaviour saw two porpoise carcasses wash up on the beach at St Cyrus and another animal die in the arms of rescuers at Arbroath Harbour in February this year.
Post-mortem investigations into the events have revealed the two adult porpoises found at St Cyrus were killed as a result of a bottlenose dolphin attack with investigations into the death at Arbroath yet to be concluded.
The carcasses of the two St Cyrus adults were found covered in deep rake marks mirroring the spacing of teeth on bottlenose dolphins and each bore a large gaping wound near the head, believed to have been pecked open by scavenging birds.
Andrew Brownlow, veterinary investigation officer with Scotland’s Rural College and the Scottish Marine Animal Strandings Scheme, said: “We can confirm that at least one of the incidents at St Cyrus was the result of a bottlenose dolphin attack and we are pretty confident the other porpoise died from the same.
“We don’t quite know what has happened at Arbroath but we think it is a young animal that was emaciated and once the blubber gets to such a low level it reduces their ability to function well.
“The teeth marks on the St Cyrus pair were pretty distinctive but we are going to check for other signs of trauma and signs of disease. We are not sure why these attacks are happening yet.
“It may be something that means the porpoises are more targeted by dolphins than others perhaps because they are foraging in the same area and just get picked on.”
Many in the marine science world were reluctant to accept the prospect that dolphins were attacking other animals, given their moniker as “the dogs of the sea” due to their oft-cited friendly nature.
However, several landmark scientific reports have proven the mammals have been responsible for a number of savage attacks on porpoises, with investigations continuing to discover why.
Mearns-based marine life scientist Caroline Weir was a key helper in the retrieval of the St Cyrus carcasses and also witnessed a similar attack take place in the coastal waters off Gourdon only days later.
She said: “On February 17 I assisted the Scottish Marine Animal Strandings Scheme with the collection of two dead harbour porpoises from St Cyrus beach in Aberdeenshire.
“The skin of both porpoises exhibited extensive tooth raking from bottlenose dolphins, and at this stage an attack by dolphins is presumed to have caused their deaths.
“Two days later I noticed some commotion in the sea just outside my house, and was able to witness an aggressive dolphin-porpoise interaction first-hand.”