A trio of killer whales attacked a boat in the Strait of Gibraltar earlier this month, damaging it so badly it sank soon after.
The May 4 incident was the third time killer whales (Orcinus orc) have sunk one ship off the coasts of Portugal and Spain in the past three years. THE orca subpopulation in this region began harassing boats, most often by biting their rudders, in 2020. Nearly 20% of these attacks caused enough damage to disable ships, says Alfredo López, orca researcher at the Task Force on Atlantic Killer Whales (GTOA), which monitors the population of Iberian killer whales. “It’s a rare behavior that has only been detected in this part of the world,” he says.
Researchers don’t know why killer whales attack watercraft. There are two hypotheses, according to López. One is that killer whales have invented a new fad, something that subpopulations of these dolphin family members are known to do. Just like in humans, orca manias are often led by juveniles, López says. Alternatively, the attacks may be a response to a past bad experience involving a boat.
The first known incident occurred in May 2020 in the Strait of Gibraltar, an area with heavy maritime traffic. Since then, GTOA has recorded 505 cases of orcas reacting to boats. Sometimes they just approached the ships, and only a fraction of the cases involved physical contact, López says. In a study published in June 2022 in Marine Mammal Sciencehe and his colleagues cataloged 49 cases of orca-boat contact in 2020 alone. The vast majority of attacks were on sailboats or catamarans, with a handful involving fishing boats and motorboats. The average ship length was 12 meters (39 ft). For comparison, an adult killer whale can be 9.2 meters (30 feet) long.
Researchers have found that killer whales preferentially attack the rudder of boats, sometimes scraping the hull with their teeth. Such attacks often break the rudder, leaving the boat unable to sail. In three cases, the animals damaged a boat so badly that it sank: In July 2022, they sank a sailboat with five people on board. In November 2022, they sank a sailboat carrying four people. And finally, in this month’s attack, the Swiss sailboat Champagne had to be abandoned and the ship sank while being towed to shore. In all cases, those on board were rescued to safety.
In 2020, researchers observed nine different individual killer whales attacking boats; it is unknown if others have since joined. Attacks tended to come from two distinct groups: a trio of juveniles sometimes joined by a fourth, and a mixed-age group consisting of an adult female named White Gladis, two of her young offspring, and two of her sisters. Because White Gladis was the only adult involved in the initial incidents, researchers believe she may have become entangled in a fishing line at some point, giving her a bad association with boats. Other adult killer whales in the area have injuries consistent with collisions or entanglements with boats, López says. “All of this should make us reflect on the fact that human activities, even indirectly, are at the origin of this behavior,” he says.
The safe rescue of everyone involved, however, suggests to Deborah Giles that these orcas have no malevolent motives against humans. Giles, science and research director of the Washington state-based nonprofit Wild Orca conservation organization, points out that humans have relentlessly harassed killer whales off the coasts of Washington and Oregon in the 1960s and 1970s, capturing young orcas and taking them away for display to the navy. parks. “These are animals that each and every one of them have been captured at one time or another – most whales multiple times. And these are whales that have had their babies taken from them and loaded onto trucks and driven away, never to be seen again,” says Giles. “And yet these whales have never attacked ships, never attacked humans.”
While it’s possible that killer whales around the Iberian Peninsula are reacting to a bad experience with a boat, Giles says, it’s pure speculation to attribute that motivation to animals. The behavior seems to be learned, she says, but could just be a fad without too much rhyme or reason — for the human mind, anyway. Famously, some members of the Southern Resident orcas that cruise Washington’s Puget Sound every summer and fall spent the summer of 1987 carrying dead salmon on their heads. There was no apparent reason for salmon hats to be fashionable in orca circles, but the behavior spread and persisted for a few months before fading away again. “We’re not going to find out what’s going on with this population,” Giles says, referring to the Iberian killer whales.
Iberian orca attacks typically last less than 30 minutes, but can sometimes last up to two hours, according to the 2022 study. In the case of the Champagne, two juvenile killer whales grappled with the rudder while an adult slammed into the boat repeatedly, crew members told the German magazine Yacht. The attack lasted 90 minutes.
The Iberian orca subpopulation is considered critically endangered, with only 39 animals when a full census was last taken in 2011. A 2014 study found that this subpopulation follows the migration of their main prey, Atlantic bluefin – a route that brings them into close contact with human fishing, military activities and recreational boating. Marine authorities recommend boaters in the area to slow down and try to stay clear of orcas, López says, but there’s no guaranteed way to avoid the animals. He and his colleagues worry that the boat attacks will come back and bite the orcas, either because the boaters are on a rampage or because the attacks are dangerous for the animals themselves. “They are at great risk of injury,” says López.