Humans have long been endangering killer whales, some of which have become a growing threat to sailboats, particularly off the coasts of Portugal and Spain.
There have already been at least 60 reported attacks in Iberian waters this year, according to a regional research group specialising in killer whales.
Reports of violent incidents began in 2020 leading Portugal's National Marine Agency to issue a statement warning sailors of the "curious behaviour" of some killer whales in that they were attracted to rudders and propellers. It advised crew members to switch-off engines if whales approached. This didn’t work.
A year later, Spanish authorities banned small boats from sailing near the coast of Cape Trafalgar following 50 encounters with killer whales, including 25 in which boats had to be towed to shore. That year, 2021, there were a total of 197 violent interactions. Last year there were 207.
The GT Orca Atlantica working group says that killer whales - also known as orcas - started deliberately attacking boats for a reason that is not altogether clear. Some scientists believe younger orcas began imitating the behaviour of an older, hostile female, which may have been traumatised following a collision with a boat or being trapped in fishing nets.
That traumatised orca may have been the one that started this behaviour of physical contact with the boats, Alfredo Lopez Fernandez has suggested. He is a biologist at the University of Aveiro in Portugal who has co-authored a study on orcas’ behaviour. He told Live Science he thought the behaviour was "defensive based on trauma" and was being imitated by other whales.
A skipper told the German magazine Yacht that two smaller whales appeared to copy the technique of a larger one when slamming into his vessel.
Six killer whales rammed a sailboat off the Straits of Gibraltar last month, breaking the rudder and piercing the hull. Coastguards rescued the people on board, but the boat sank. Rescue authorities have had to provide rapid-response crews and helicopters for such events.
Many damaged vessels can be saved and brought to shore, but some cannot be bailed out and unavoidably sink as another did off the coast of Portugal last November when its hull was cracked open by orcas. It is likely to go on and on without any truce or peace plan in sight.
Killer whales are beautiful mammals, the largest of the oceanic dolphin family. They have large mouths and many sharp, interlocking teeth designed not for chewing but ripping and tearing their fish diet. Orcas occur in oceans across the world growing to as much as nine metres (29.6 feet) in length and weighing up to 10,000 kilos (10 tonnes). Males can be up to twice as heavy as females.
Iberian orcas are smaller than those in the Pacific. They are an isolated sub-population, a pod of about 32 individuals. A study has found that inbreeding is hampering their population growth.
Those feeding on red tuna along the Iberian shores share the main characteristics of their cousins elsewhere. They are social animals living in close communities with their own culture and constantly communicating with one another in various vocal ways.
Humans have been harming if not killing orcas by polluting the seas with plastics, spilt oil and other contaminants. Fishing nets are another hazard. Boat engine noise is disruptive to their normal underwater hearing and communications.
Orcas attack boats that are often twice their size, but they do not show aggression to humans. While it is difficult to come up with a peace plan, the killing of killer whales is unthinkable as they have a reputation in mythology as being the “souls of humans' ', and, more importantly, they are protected under international, EU, Portuguese and Spanish law.
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