Attacks by orcas against yachts and sailboats have surged in the Strait of Gibraltar since 2020, a phenomenon initially perplexing to scientists. According to a team of biologists, this behavior is more a game for the cetaceans than a form of aggression.
A report from the International Whaling Commission, commissioned by the Spanish and Portuguese governments, indicates that orcas have engaged in at least 673 interactions with boats in the Strait of Gibraltar over the past four years. These interactions range from simple encirclement to violent attacks, primarily targeting the ship's rudders. Since 2020, at least four boats have sunk due to these encounters.
Of the 40 orcas recorded in the Iberian Peninsula, only around 15 juveniles and adolescent males are involved in these interactions. The scientists believe the behavior is more about play than aggression, as orcas are known for their social and extremely intelligent nature. According to the researchers, young orcas likely observed their elders playing with rudders and mimicked this behavior.
"Killer whales are known to play with objects or other animals in their environment, sometimes to the point of damaging them. Therefore, using terms like 'attack' to describe these interactions is inappropriate," the experts wrote in their report.
Orcas are also known to develop temporary, unusual behaviors. For example, a group of cetaceans from the northwest Pacific was observed playing with porpoises until they killed them, without ever eating them. The researchers suggest that an abundance of food, particularly bluefin tuna, in the Iberian Peninsula waters could also be a factor. With more food available, orcas spend less time hunting and more time 'playing.'
The report emphasizes the importance of not using deterrent measures like firecrackers or electric shocks, which are not only ineffective but could also increase the orcas' aggressiveness. Instead, experts recommend modifying boat rudders to make them less attractive to the orcas.
- The peculiar behavior began with three young orcas and quickly spread through the entire community of killer whales frequenting the Strait of Gibraltar. These interactions have resulted in several hundred boats being targeted since 2020, with seven boats sinking, including a yacht on May 12.
- In 2023, former Vendée Globe skipper Sébastien Destremau reported a harrowing experience when his sailboat was pursued by eight orcas for almost an hour. Adult orcas can measure between 6 to 9 meters and weigh up to 7 tonnes, making their interactions with boats particularly daunting.
- Recent research involving aerial and underwater video recordings, along with orca tracking by tags, has helped scientists better understand this behavior and develop measures to mitigate the risk of harassment.
