When Daniel Kriz noticed a pair of killer whales beneath his boat whereas crossing the Strait of Gibraltar in April, he thought: “Not once more.”
For Kriz, a veteran skipper who was delivering a racing catamaran throughout the Atlantic, it was the second such encounter in three years, after a pod of orcas had surrounded and disabled his boat in 2020.
“We were suddenly surprised by what felt like a bad wave from the side,” he mentioned of the latest incident.
“That happened twice, and the second time we realised that we had two orcas underneath the boat, biting the rudder off.
“They have been two juveniles, and the adults have been cruising round, and it appeared to me like they have been monitoring that motion.”
The four people on board the vessel didn’t suffer any injuries, but without full control of the boat, Kriz had to reach the nearest marina using only his engines.
The whales had destroyed both rudders — the submerged control surfaces that steer a boat — in what seemed like a streamlined version of the encounter that occurred three years prior.
“In 2020, the assault lasted virtually an hour and was not as organised,” Kriz said.
“This time we may hear them speaking below the boat. It solely took about 10 to fifteen minutes.”
Kriz’s experience isn’t an isolated one.
In the past three years, the Strait of Gibraltar — a 13km-wide sea corridor separating Europe from Africa — has been a hot spot of activity, with over 500 interactions between orcas and boats.
All of the encounters involve some combination of the same roughly 15 animals, which have sunk three vessels and disabled dozens more, according to Mónica González, a marine biologist with CEMMA, or Coordinadora para o Estudo dos Mamíferos Mariños, a nongovernmental organization that is gathering data about the orcas in the strait.
The reason why certain whales are taking such a forward interest in boats is still unclear, but experts have a couple of theories.
The Strait of Gibraltar is one of the world’s busiest waterways, and while orcas only approach a tiny fraction of the boats that go through, about one in five interactions result in severe damage requiring a tow, González said.
The latest sinking occurred in early May, when the sailing yacht Alboran Champagne was attacked by three orcas and completely flooded; it was then abandoned and left adrift to sink.
The current rate of interactions is at a seasonal peak of about 20 to 25 per month: “There are extra encounters in the summertime as a result of the orca’s prey, bluefin tuna, is within the strait, so they’re ready there,” González said.
“When the summer season ends, the tuna strikes to the north of Spain and the orcas comply with them.”
Killer whales are the largest members of the dolphin family.
The powerful animals are highly social sea mammals and can swim at speeds of up to 48km/h, according to the National Oceanic and Atmospheric Administration.
An adult can weigh up to 11 tons and reach 9.7m in length.
Individual orcas can live as long as 90 years in the wild, and the global population is estimated at around 50,000.
González said that the total number of killer whales in the strait is just 40 — a subpopulation listed as critically endangered by the International Union for the Conservation of Nature — with about 15 approaching boats.
And among the offenders, there are only two adults, which might offer clues to their motivation.
“We have two theories about why these interactions began,” she said.
“The first is that the orcas are simply taking part in, and the opposite is that one animal suffered an aversive second and the orcas are attempting to cease the boats to forestall it from taking place once more — however we do not know precisely what occurred within the first place.”
The average size of the vessels approached is about 12m, and the usual pattern for an interaction involves the orcas approaching the boat silently, swimming under it, lightly touching it and then — in the most extreme cases — going for the rudder.
When the animals do, they can quickly make a boat pivot 360 degrees, causing danger and distress to its occupants.
The encounter usually ends once the killer whales break the rudder or the boat comes to a complete stop.
“It is more and more doubtless that an animal has began this behaviour after an incident with a ship,” biologist Alfredo López Fernandez, an adjunct researcher at the University of Aveiro in Portugal and one of the authors of the study, said.
He points to the history of a female orca known as White Gladis as evidence: “She is the one grownup who began in 2020 with the interactions together with seven different juveniles.”
There are clues suggesting that White Gladis may have become entangled in fishing gear — a common threat to orcas — either as an accident or during an illegal fishing attempt, López Fernandez said.
Many boats use fishing lines at the stern, and this seems to be one of the motivating factors for orcas to approach and investigate the rear of the craft.
Earlier this year, another killer whale in the area was spotted with a fishing line on its body, he said.
Since White Gladis’ supposed traumatic event, two adult killer whales may have started teaching juveniles how to approach boats to disable their rudders — which seems to track with Kriz’s observation about the evolution of the behaviour between his two encounters.
“Orcas are a really matriarchal society and all juveniles look as much as these crucial females within the pod; the juveniles are copying their behaviours as a result of they consider that if these crucial people do one thing, they need to do the identical to make sure their very own survival,” González said.
Worryingly, the interactions seem to be on the rise: “From January to May, we have seen a rise in comparison with final 12 months, however it’s too early to say if this will probably be maintained all through the remainder of the season,” López Fernandez said.
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According to Hanne Strager, a marine biologist and author of The Killer Whales Journals, while the traumatic origin of the behaviour can’t be ruled out, she also believes that play is a more viable explanation.
“They are drawn to the rudder, as a result of it’s constructed to be movable and so they discovered that in the event that they push it to the facet they’ll make cracks within the hull — and that is what is believed to be the reason for the sinking of a few of these boats,” she said.
“They might imagine it is enjoyable — like kicking a ball onto a garden to see what occurs. But for the people who find themselves experiencing this on their multi-million-dollar boat, it is not enjoyable, it is not play. It’s fairly scary.”
However, there’s no evidence that the whales want to harm humans, Strager added.
“I’ve spoken to one of many crew members of one of many boats that went down, who can also be a marine biologist, and he mentioned he by no means felt that there was any aggression,” she said.
“They did not care in regards to the folks, and as quickly because the boat sank, they went away.”
Kriz also ruled out any openly hostile intent on the mammals’ part.
“I do not assume that is aggressive behaviour and undoubtedly not in the direction of the people. They principally play with the rudders till they get them off,” he said.
“They may see us — we have been filming and taking footage of them from the boat and there was no interplay in any respect from both facet.
“They didn’t bump the boat in any other place. Just the rudders.”
Killer whales are extremely smart and recognized for frolicsome behaviours, which may generally flip into cultural fads amongst a small group of people.
González talked about how in 1987, within the waters of the Pacific Northwest, one orca began carrying lifeless salmon on her head, and the behaviour shortly unfold to the remainder of the pod, solely to final a 12 months.
“They certainly do play and they play with all kinds of things,” Strager mentioned.
“I’ve seen them swimming around with a jellyfish on the nose for a while.
“Several of them did this and there was no rationalization apart from it was enjoyable.
“I’ve also seen them whack small seabirds from the water surface, which they are not eating afterwards.
“They additionally play with one another.”
In case of an encounter, it’s best to do nothing.
“The official advice is to not do something in any respect, flip off the engine or decrease the sails and be as uninteresting to the killer whales as doable. Don’t yell, do not shout, do not scream,” Strager advised.
For the critically endangered whales, getting a bad reputation could be fatal.
“Some sailors are recommending that you just throw chloride, diesel, firecrackers and even dynamite within the water,” Strager said.
“But this very susceptible little inhabitants of killer whales is dependent upon our love for them. They depend upon our safety.”
“Bottom line, we’re of their territory,” he said.
“Maybe we should always designate some form of hall the place boats enter or exit Gibraltar, one thing like delivery lanes,” he added, noting that tracking the animals’ location only works up to a point because “they have been throughout.”
Is it likely that the whales will get bored of smashing rudders anytime soon? Don’t bet on it, González said.
“Personally I do not assume they’ll cease quickly,” she said.
“Maybe little by little, however not within the brief time period.”
Source: www.9news.com.au
