Three-year enigma of ‘Scottish’ killer whales solved

Some of the ‘mystery killer whales’ encountered in Scotland in 2018.

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A mystery identifying a pod of killer whales, spotted in Vatersay in Scotland and Børøyfjorden in Norway, has finally been solved using data from the Norwegian Orca Survey and the Scottish Killer Whale Catalogue.

Previously unknown to Scottish and Norwegian scientists, the pod has now been identified using records responsible for the first killer whale match made between the two countries.

The story begins in Scotland, off Vatersay on Scotland’s west coast, on June 23 2018 when a confirmed sighting of a killer whale pod was made by the Hebridean Whale and Dolphin Trust. The animals were spotted 300 metres away from the charity’s research yacht Silurian.

The trust’s science officer Becky Dudley was on board and took photographs that – three years later – made the Norwegian match possible.

The breakthrough came on Saturday July 10 this year after citizen scientist Asmund Aasheim photographed a pod of six whales in Børøyfjorden and sent his images to the Norwegian Orca Survey, where Dr Eve Jourdain found the killer whales were not familiar from Norwegian records.

As the colouration on the animal’s backs – known as a saddle patch – looked different to that of killer whales normally seen around Norway, Dr Jourdain looked further afield, comparing the individuals against other national records. She found a match in the Scottish Killer Whale Catalogue – a key research document containing the best available images of all known living killer whales seen in Scottish waters.

‘From the moment I first took a look at Asmud’s photos, I knew these killer whales were ‘different’ from our Norwegian killer whales,’ said Dr Jourdain.

‘Following our routine protocols, I tried to identify them from our Norwegian catalogue but, as expected, I found no match. When it came to mind that I should browse through the Scottish catalogue, I had a strong feeling I would find them there. It was incredible to find this first photographic match between Norway and Scotland.’

Science officer Becky Dudley, who contributed her sighting to the Scottish Killer Whale Catalogue, said: ‘The encounter with this group of killer whales in 2018 was one of the most amazing experiences I’ve had on Scotland’s west coast. It was made even more exciting when, despite much investigation and collaboration with other organisations,  the identity of this pod remained a mystery.

‘I am thrilled the group has been matched to the group seen in Norway over three years later. It highlights how much there is to learn about the marine life in our oceans.’

Anyone can get involved to help track the movements of individual animals and contribute to marine conservation efforts by sending in sightings and photographs of whales, dolphins, porpoises and basking sharks. Sightings for the west coast of Scotland should be registered with the Hebridean Whale and Dolphin Trust via www.whaletrack.hwdt.org.

With marine mammals at risk from human activities including climate change, entanglement, pollution, underwater noise and habitat degradation, ongoing and long-term research is crucial to improve understanding of the impacts on whales, dolphins and porpoises – collectively known as cetaceans – and how to protect them.

A close-up image of killer whales showing the saddle patch which helps to identify the creatures.

Some of the mystery killer whales encountered in Scotland in 2018. No_F30killer01

A close-up image of killer whales showing the saddle patch which helps identify the creatures. No_F30killer02