The yacht Grazie Mamma II carried its crew along the coastlines and archipelagos of the Mediterranean. Its last adventure was off the coast of Morocco last week, when it encountered a pod of orcas.
The marine animals slammed the yacht’s rudder for 45 minutes, causing major damage and a leak, according to Morskie Mile, the boat’s Polish operators. The crew escaped, and rescuers and the Moroccan Navy tried to tow the yacht to safety, but it sank near the port of Tanger Med, the operator said on its website.
The account of the sinking is adding to the worries of many sailors along the western coast of the Iberian Peninsula, where marine biologists are studying a puzzling phenomenon: Orcas are jostling and ramming boats in interactions that have disrupted dozens of voyages and caused at least four boats in the past two years to sink.
The largest of the dolphin family, orcas are playful apex predators that hunt sharks, whales and other prey but are generally amiable to humans in the wild. The orcas hunting in the Strait of Gibraltar are considered to be endangered, and researchers have noticed an upsurge of unusual behavior since 2020: A small group of the marine animals have been battering boats in the busy routes around Portugal, Spain and Morocco.
While most interactions occur in the waters of southwestern Europe and North Africa, an orca also reportedly rammed a yacht some 2,000 miles north off the coast of Scotland, according to The Guardian.
“Orcas are complex, intelligent, highly social,” Erich Hoyt, a research fellow at Whale and Dolphin Conservation and author of “Orca: The Whale Called Killer,” said. “We’re still at the early stages of trying to understand this behavior.”
Researchers have pushed back at the idea that orcas are attacking vessels. Instead, they theorize that the rudders of boats have become a plaything for curious young orcas and that the behavior has become a learned fad spreading through the population. Another hypothesis, according to biologists who published a study on the population last June, is that the ramming is an “adverse behavior” because of a bad experience between an orca and a boat — though researchers tend to favor the first.
It is unclear what will stop the ramming, whether it’s playful or otherwise, a point that has left anxious skippers traveling these parts sharing advice in Facebook groups dedicated to tracking such interactions.
“It’s been an interesting summer hiding in shallow waters,” said Greg Blackburn, a skipper based in Gibraltar. Orcas slammed into a boat he was commandeering in May and chewed at the rudder, he said, though the vessel was able to return to shore.
The encounter left an impression: On a recent trip to Barcelona, Mr. Blackburn had to pass through a patch where orcas had been sighted the week before. “I genuinely felt sick for about three hours,” he said, “just watching the horizon constantly for a fin to pop up.”
Conservationists, maritime rescue groups and yacht clubs are partnering to navigate the challenge of preserving an endangered population and helping sailors avoid calamity. The Cruising Association, a club supporting sailors, has recommended safety protocols for orca encounters, such as disconnecting the boat and staying quiet. Skippers have offered one another anecdotal advice to deter attacks, including throwing sand into the water and banging loudly on the boat.
Before leaving shore, seagoers can also consult digital platforms that now track reported orca sightings and interactions in the region. This can help them avoid the animals, or charter a route closer to shore, said Bruno Díaz López, a biologist and the director of the Bottlenose Dolphin Research Institute based in Galicia, Spain.
“We suggested the boats stay in shallow waters,” he said, adding that they had noticed more boats changing their journeys. “Maybe the trip takes longer, yes. But it is worth it.”
Mr. Blackburn, the skipper, said he had heard of people resorting to throwing firecrackers into the sea to try to scare the animals away, adding that the boats served as people’s homes on the ocean. “At the end of the day, if you’re protecting your home what are you going to do?”
But the ocean is the orcas’ home, and conservationists say scaring the animals is not a solution.
“It is not about winning a battle, because this is not a war,” Mr. López said. “We need to be respectful.”
