Scientists from the University of Aveiro in Portugal have found that reports of encounters with aggressive killer whales off the coast of the Iberian Sea are becoming more frequent. The research was published in the journal Marine Mammalian Science.
On the night of May 4, 2023, three killer whales attacked a yacht in the Strait of Gibraltar, off the coast of Spain, damaging the ship’s steering wheel.
“There were two small and one large killer whale. While the smaller ones swung the ship’s rudder from behind, the larger one backed up several times and slammed into the ship from the side with all its might. Two small killer whales followed the larger equipment and crashed into the boat after it “dispersed” a bit, Captain Werner Schaufelberger told the German edition of the Yacht.
According to the researchers, reports of encounters with aggressive killer whales (orcinus orca) appeared on the coast of the Iberian Sea in May 2020 and is becoming more frequent. The attacks appear to be mainly aimed at sailboats and follow a clear pattern, with killer whales approaching from the stern (back of the yacht) to hit the helm and then losing interest after successfully stopping the boat.
Scientists say the escalation of violence against boats is a new phenomenon. Researchers believe that a traumatic event can cause a change in a killer whale’s behavior that the rest of the population has learned to imitate.
“Killer whales do this deliberately, of course, we don’t know the source or the motivation, but the traumatic defensive behavior as the source of all this is becoming clearer to us every day,” the scientists explained.
The authors of the article suspect that the female killer whale, which they call White Gladys, escaped collision with a boat or being trapped while poaching. This event may have caused him to perceive the ships as a threat later on. Other killer whales mimicking it may contribute to the spread of such behavior.
Since the anomalous interactions began in 2020, four killer whales belonging to the aggressive subpopulation found in Iberian waters have died, but their deaths cannot be directly attributed to boat encounters. If this situation continues or worsens, it could become a real problem for the safety of seafarers and killer whales. Ships sank in three of the 500 recorded combat incidents since 2020. In general, killer whales interact with about one in a hundred vessels.