An orca has repeatedly rammed a yacht off the coast of Scotland's Shetland Islands, following similar incidents near southern Spain and Portugal in which boats were damaged.
Wim Rutten, 72, was sailing from the town of Lerwick to Bergen, south-west Norway, when an orca hit the stern of his boat several times.
“What I felt was most frightening was the very loud breathing of the animal,” said Mr Rutten, a retired physicist, told The Guardian.
The orca swam behind the boat before disappearing. "But [it] came back at fast speed, twice or thrice ... and circled a bit,” Mr Rutten said.
“Maybe he just wanted to play. Or look me in the eyes. Or to get rid of the fishing line.”
In May, a British sailing boat was damaged when it was attacked by orcas off southern Spain.
“What started off as a seemingly unique encounter ended with orcas breaking our rudder off the boat, then proceeding to tear off bits of the boat for over an hour,” crew member April Boyes said at the time.
Experts have suggested juvenile orcas looking to play could be responsible for the interactions.
Dr Conor Ryan, a scientific adviser to the Hebridean Whale and Dolphin Trust, said such behaviour could be "leapfrogging through the various pods/communities" of orcas.
Dr Deborah Giles, science and research director at Wild Orca, said there had been an increase in the number of encounters between orcas and boats in the Strait of Gibraltar.
“I think what we are probably seeing in the Shetland area is whales coming into contact with vessels that are now being reported because of what’s happening off Portugal and Spain," she told BBC Radio 4.
“I think what’s probably happening in the Strait of Gibraltar area is a situation where one animal had an encounter with a sail boat, there was something about the keel or rudder, I believe possibly the keel, which is the big long part that sticks down in the water, that was interesting to the whale.
“It might have been a vibration, or water moving around that part of the boat, that was attractive to the whales for whatever reason. And then other whales maybe saw that and started mimicking that behaviour.”
Dr Giles does not believe what happened in the North Sea was related to the attacks near Spain.
Orca interactions have been described as “antagonistic” and “retaliatory”, but Dr Giles dismissed those claims.
“I truly don’t believe that’s what’s happening in any of the cases that have been reported recently," she said.
Orcas have been seen several times in Abu Dhabi's waters. In May, the environmental health and safety unit at the Department of Culture and Tourism advised several hotels to ban swimming at beaches following the sightings.
GTOA, a research group that monitors the Iberian orca subspecies, recorded at least 20 interactions between orcas and small vessels in the Strait of Gibraltar in May.
In 2022, a total of 207 interactions were reported.
In May, the sailing yacht Alboran Champagne was damaged by orcas and took on water. It could not be towed and was left to sink.
Another yacht was pursued by orcas during poor weather off the Moroccan coast.
The recent increase in orca encounters has been linked to a killer whale matriarch named White Gladis.
The orca suffered a “moment of agony”, such as becoming trapped in a fishing net or colliding with a boat, that changed her behaviour, Dr Lopez Fernandez told Live Science.
“That traumatised orca is the one that started this behaviour of physical contact with boats,” he said.
“We do not interpret that the orcas are teaching the young, although the behaviour has spread to the young vertically, simply by imitation, and later horizontally among them, because they consider it something important in their lives."
