2 Yacht Passengers Rescued After Whales Sink Their Boat in Growing Trend That Has Scientists Divided

Orcas have sunk another yacht off the Strait of Gibraltar — the latest incident in a growing trend that initially began in 2020.

A sailing yacht went down in Moroccan waters in the Strait of Gibraltar after an unknown number of orcas repeatedly rammed into it, according to BBC, NBC News and Fox News.

At around 9 a.m. local time on Sunday, May 12, a pair of crew members aboard the vessel, Alboran Cognac, reported that orcas damaged their yacht, which had been about 14 miles from Cape Spartel in Morocco at the time, Fox News reported.

Spain's maritime rescue service told BBC that the two passengers called for help after they felt something hit the hull and rudder, which caused the yacht to take on water. 

A helicopter was sent by Spain's maritime rescue service to the location to rescue the crew members and a nearby oil tanker was also redirected to their location to provide assistance. The oil tanker was able to respond quickly and the two crew members were taken onboard and transported safely to Gibraltar, per the outlets.

Meanwhile, the crew members’ sailing yacht was left adrift and eventually sunk into the ocean. 

Reports of aggressive encounters between orcas and sailboats in the Iberian coast off of Europe began in 2020, according to Maritime Executive, and the incidents have ramped up since then.

Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.

The reason behind the growing number of boat attacks by orcas in the area has perplexed researchers, though some have theorized that the killer whales were taught this behavior by other members of their species. 

Alfredo López Fernandez, a marine biologist at the University of Aveiro in Portugal, told Live Science he believed the interactions began after one orca, called "White Gladis," who had been “traumatized’ by an incident with a vessel and “started this behavior of physical contact" with boats. He said other killer whales then copied it.

Scientists from research center CIRCE noted that a group of three orcas from the same pod have been involved in several boat rudder interactions, though they added that they believed the orcas were "engaging with sailboats as a form of entertainment" rather than a form of hunting.

Marine biologist Dr. Renaud de Stephanis told the BBC, “From what I’m seeing, it’s mainly two of those guys [the Gladises] in particular that are just going crazy. They just play, play and play. . . . It just seems to be something they really like and that’s it.”

“I’ve seen them hunting,” the biologist added. “When they hunt, you don’t hear or see them. They are stealthy, they sneak up on their prey. I’ve seen them attacking sperm whales - that’s aggressive....but these guys, they are playing."