Killer whales: five years after first attack on yacht

It's no longer news: killer whales attack yachts and, as it turns out, they can pose a serious danger to boats. From October 2024 to March 1, 2025, according to a report by the website orcas.pt, 20 "attacks" were registered. The first reports of the raging sea predators began to appear in 2020 and since then incidents off the coast of Portugal and Gibraltar have not stopped.

Five years later, there is still no clear answer about the reasons for such behavior of killer whales, there are no strict instructions for the crew (except not to harm the animal). However, recommendations for yachtsmen are becoming more accurate and complete every year.

The article is an adaptation of the material "Orcas kommen nicht zur Ruhe" by Kerstin Zillmer for the website Float.de.

Do killer whales attack... or cooperate?

Suddenly, disagreements arose in the scientific community regarding the linguistic side of the issue. Thus, many scientists and researchers have a sharply negative response to the use of formulations such as "killer whales attacked" or "attacked" yachts. In their opinion, such definitions create the illusion that killer whales "have" some specific evil intentions.

A source: floatmagazin.de

This is, to put it mildly, not true, as the behavior of animals in their natural environment cannot be described with the epithets “good” or “bad.” Oceanographers prefer to use the verb “interact” when talking about incidents with killer whales. However, the fact remains that killer whales may “interact” with yachts, but this “interaction” can cost the yachtsman and crew a pretty penny.

Interaction with yachts

Since 2020, marine biologist and head of Circe, Renaud De Stefanis, has been studying the behavior of cetaceans off the coasts of Portugal and Spain. Together with the Spanish Ministry of the Environment's MITECO foundation, he launched the Life Intermares project the year before last.

The project is aimed at studying the dynamics and features of interaction (we are talking about attacks on yachts, and literally about how killer whales behave, - editor's note) of killer whales and sailing yachts in the Strait of Gibraltar. As part of this project, tracking devices were attached to six killer whales, which helped to record their routes using satellite. As it turned out, among this group of cetaceans, there was one individual that periodically interacted with sailing yachts.

Behavioural features of killer whales

At the International Congress on the Situation of Killer Whales in Madrid in February 2024, recommendations for seafarers were adopted, resulting from the project. Renaud de Stefanis presented his scientific results at the congress and compared them with those of his colleagues.

He explained the cetacean situation this way: "The killer whales around Gibraltar hunt bluefin tuna. They move around an area about two kilometers in diameter for two to three hours, waiting for schools of tuna. During this time, they have free time, so to speak. If a sailboat crosses the area at this time, they begin to interact with it."

Source: orcaspirit.com

Killer whales are highly intelligent and social creatures. All currently available scientific evidence indicates that killer whales' interactions with sailboat rudders and keels are not driven by human motives such as revenge or anger. Scientists view these interactions as more of a playful and complex exploration of the environment that the whales learn from each other. Researchers have noted that it is usually the older animal that acts and the younger one that observes. They are generally unaware that they are putting humans in danger.

The analysis of killer whale behavior also provides new insights into their hunting tactics and shows how important resting areas are for the animals when hunting tuna. Invasion of their territory interferes with their hunting. To avoid interactions with killer whales, sailors and yachtsmen should avoid areas where the animals feed.

Quickly passing the area is the best option

Renaud de Stefanis says: "A boat that moves quickly and without stopping through the two-kilometre hunting zone of the killer whales is more likely to avoid problems and encounters with the cetaceans."

This approach is in line with the officially approved tactics of the Coast Guard and the Spanish Ministry of Transport. That is, if a yacht finds itself in an area of killer whale activity, it should proceed at maximum speed in a straight line to shallow water in the opposite direction from this very area of activity. Killer whales in shallow water are less likely to attack a yacht.

About depth and shallow water: the 20 meter rule

Satellite observations show that killer whales rarely stay at depths of less than 30 meters. This fact confirmed the long-standing fact that in shallow waters killer whales only rarely interact with yachts. In addition, there is a very specifically designated area that is best avoided if possible. It is marked with a red line in the photo below.

Source: floatmagazin.de

De Stefanis advises: "Stay away from the designated area! If you stay close to the shore, you won't have any problems, but if you head straight into the red zone, you will. If the orcas do start to get active, get away from there as fast as you can, accelerate, and leave the two-kilometer zone. This will prevent contact with the orcas by 90 percent."

Statistics and dynamics of encounters with killer whales

Let's look at the actual statistics. So, of all the sailboats that passed through this region in 2023, only 2.8% reported any interactions with killer whales. Again, in this context, "interactions" do not mean attacks by cetaceans, but rather the fact of an encounter.

In 2024, this figure was only 0.6%. This drop is due to the fact that the vast majority of yachtsmen avoided the above-mentioned zone. Killer whale researcher De Stefanis is pleased: “Since we issued behavior and routing recommendations in mid-2023, the number of interactions in Spanish coastal waters has decreased by 70 percent.”

The results of the animal behaviour study and the recommendations for yacht crews remain valid two years later. The recommendations have also been refined thanks to more than 400 sighting reports from affected yachtsmen.

Current view of the problem 

At least one question about killer whale attacks has been answered: killer whales are not irritated by engine noise. The cetaceans are excited by the sight of sailing yachts because of the characteristic shape of the hull and the free-standing rudder blade. There are no recorded cases of a killer whale approaching a yacht with a classic keel that smoothly turns into a rudder.

Contrary to old recommendations, modern regulations recommend leaving engines running. This should signal to the orcas that this is not a living creature and should not be played with.

Source: livebreathescotland.com

Regarding shallow waters, the method works, but without a 100% guarantee of safety. If before going out to sea it became known that somewhere nearby there is a pod of killer whales hunting, then it is better to stay in the harbor that day. If it was not possible to avoid going out to sea, then in the indicated risk zones it is necessary to keep a constant watch.

Information is an important aspect of traveling in orca habitats. If you spot orcas, you should report it on Channel 16 with the coordinates, and also pass the information on to the Coast Guard.

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20.03.2025