VIDEO: 'We didn't even see them coming': Orcas are attacking boats in Europe
01:17 - Source: CNN
CNN  — 

When Daniel Kriz saw a pair of killer whales underneath his boat while crossing the Strait of Gibraltar in April, he thought: “Not again.”

For Kriz, a veteran skipper who was delivering a racing catamaran across 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 said of the recent incident. “That happened twice, and the second time we realized that we had two orcas underneath the boat, biting the rudder off. They were two juveniles, and the adults were cruising around, and it seemed to me like they were monitoring that action.”

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 attack lasted almost an hour and was not as organized,” Kriz said. “This time we could hear them communicating under the boat. It only took about 10 to 15 minutes.”

Kriz’s experience isn’t an isolated one. In the past three years, the Strait of Gibraltar — an 8-mile-wide (13-kilometer-wide) sea corridor separating Europe from Africa — has been a hot spot of activity, with over 500 interactions between orcas and boats.

Skipper Daniel Kriz said orcas in the Strait of Gibraltar approached and damaged the boat he was helming this past April and in 2020. “Bottom line, we’re in their territory," he told CNN. "We need to adjust.”

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.

Two 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 1 in 5 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. As recently as June 22, two different teams participating in the annual Ocean Race sailing event reported run-ins with orcas in the strait, but neither yacht sustained damage.

The current rate of interactions is at a seasonal peak of about 20 to 25 per month: “There are more encounters in the summer because the orca’s prey, bluefin tuna, is in the strait, so they are waiting there,” González said. “When the summer ends, the tuna moves to the north of Spain and the orcas follow 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 30 miles per hour (48.3 kilometers per hour), according to the National Oceanic and Atmospheric Administration. An adult can weigh up to 11 tons and reach 32 feet (9.7 meters) 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.