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Desperate sailors defend themselves against orcas with fireworks and sand

Orcas are spread over most of the globe, but half of the population is threatened, mainly due to pollution. Adult males can weigh over five tons and live an average of 30 years. No attacks on humans have been documented as of yet. Illustration: Mike Dohety

In half a year, I will sail to the Mediterranean.

As a fairly experienced sailor, I am used to planning for a little bit of everything: stormy weather, tides, emergency repairs, etc.

But the trip now suddenly includes a completely new challenge: orcas.

A little over two years ago, the first curious reports came of sailboats in the Strait of Gibraltar suffering damage to their rudders after young orcas rammed into them and broke them.

Since then, the number of incidents has grown steadily, and this year it has really upsurged.

From Brest in North-West France to Gibraltar, there are now daily reports of sailboats being attacked, and the rescue operations are so numerous that there is a temporary sailing ban.

Two boats have sunk

Young orcas attack the boats’ rudders in groups by biting and ramming into them for up to an hour, or until the rudder comes loose.

Meanwhile, the older whales swim around further away from the scene.

In some cases, the helmsman is hit by the tiller and suffers injuries when the up to 5.5-ton-heavy whales ram into the rudder. In other cases, the boat sinks, as has happened twice now, most recently with a French boat “The Smousse”, an Oceanis 393, which sank on 1 November 14 nautical miles west of Viana do Castelo in Portugal.

The attack took place in the middle of a beautiful, sunny day, and skipper Elliot Boyard and his three crew members followed official recommendations to lower sails, stop the boat, and keep quiet. But this did not help:

“The orcas circled the boat and rammed into the rudder. They took turns biting the rudder and shaking it... The interaction continued, but we couldn’t manoeuvre, especially because the orcas were constantly biting the rudder. After about an hour, a leak appeared at the rear, and we sank.”

The French sailboat “The Smousse” was sunk by orcas on 1 November. Illustration: Ukendt

The account can be read in detail in a report to the Cruising Association (CA), which, together with several research groups, including the Atlantic Orca Working Group, is struggling to understand what is going on and what can be done about it. The orcas are endangered and protected, so it is strictly forbidden to disturb them.

Professor from DTU: Completely new behaviour

The growing data collection makes it possible to send out warnings about where the orca attacks are most frequent, and they are sent out in the form of educational maps with colour codes showing where to stay away from.

The orcas move all the time, depending on where the increasingly smaller population of tuna currently is. In recent months, for example, the attacks have been concentrated in the waters around Lisbon.

The sailing community and the researchers have collected data on 350 interactions since 2020, and in combination with numerous mobile camera recordings, the researchers now have a fairly good picture of the attacks, which are, however, certainly underreported.

In 2022, 70 percent of reported interactions resulted in damage to the boat, and in 24 percent of cases, the rudder was so damaged that the ship needed assistance.

On the basis of information from sailors and rescue services, the Atlantic Orca Working Group regularly publishes announcements about the whereabouts of the active orcas. Graphics: Nas / Source: GTOA Illustration: På baggrund af informationer fra sejlere og redningstjenester udgiver forskergruppen GTOA løbende meddelelser om, hvor de aktive spækhuggere befinder sig

The researchers also have a myriad of other data points such as sonar being on or off, the type of rudder, the colour of the bottom paint, the speed of the boat, etc. And so far, there is no pattern.

The orcas attack all kinds of rudders, colours, and boats at speeds up to 25 knots. However, there are some indications that black bottom colour and a so-called spade rudder lead to more attacks. But the statistical uncertainty is too great for the researchers to draw any conclusions.

“At the moment, we really don’t know why they behave the way they do. We have never seen this behaviour of constant and continuous attacks on rudders before. It’s a completely new situation, and many theories are at play,” says Professor David Lusseau from DTU, who has studied marine mammals for 25 years, including orcas at Vancouver Island.

Only 14 active orcas

Like other researchers, David Lusseau insists that it is always the same young individuals that lead the attacks—and based on numerous recordings, they have been named Gladis (after “gladiator”).

Earlier this year, a report on the orca attacks was published by the International Whaling Commission (IWC), and in it the researchers explained that the attacks were carried out by only 14 individuals divided into three pods. The most active one seems to be a mother named Blanca-gb who attacks with her daughter Filiabres and sister Dalila.

After the first interactions with boats, the researchers came to the conclusion that it was mainly two groups of orcas that were responsible for the attacks:

Usually, the younger ones attack, while the older ones only participate sporadically or stay on the fringes. Gladis Blanca-GB and Gladis Negra-GN are among the most active orcas in the attacks, and the latter had a large head injury during the first attacks in 2020 and has since had a wound on its fin. Illustration: Lea Woer

Although the attacked sailors usually hide in the cockpit in fear while the attacks are happening, the researchers refuse to call them attacks.

They call them interactions and insist that the orcas are 100 percent focused on the rudder—and that the boat needs to be moving for them to attack. They are quite indifferent to the engine, although there are signs that on rare occasions, they lose interest if the boat reverses.

In a study published in the journal Marine Mammal, the researchers point out that the orcas are neither afraid nor aggressive, but just curious. They seem to be playing.

Balancing a salmon on top of their head

Orcas are known to exhibit strange behaviour that often spreads to other members of the group.

For example, back in 1987 an orca off the West Coast of the US began swimming around with a dead salmon on its head, and this behaviour spread to others in the group until the craze went out of fashion again.

Other orca pods on the West Coast have moved fishermen’s crab and shrimp boxes around (although the orcas themselves do not eat crabs or shrimp) for no other reason than playing around.

However, the deviant behaviour among the young orcas usually stops when they get older, and therefore several researchers, such as biologist Alfredo López, expect that the attacks will stop.

Alfredo Lópes, biologist at the University of Santiago and a member of the Atlantic Orca Working Group, told one of the leading yachting magazines, Yacht Monthly, that there is a possibility that the behaviour started because a pod had a bad experience with a sailboat.

In addition, one of the most active orcas, Gladis Negra, was observed with a distinct wound from a severe head injury when it was involved in the first interactions back in 2020.

That theory matches similar theories that it may have started with a sailboat hitting a young orca, or that the growing noise in the area from ship traffic has angered them. However, the dominant theory in the research community is still that it is curious play, and Professor David Lusseau from DTU paints a picture of young orca bullies playing tricks.

“We are dealing with very intelligent animals, and one possibility is that they do it for the thrill. We are familiar with behaviour in land mammals such as elephants, which are known to cause problems in rural areas if they have not been properly socialized into the herd,” he says.

In other words, it is possible that these are rebellious teenagers that lack older role models, and therefore David Lusseau also hopes that new research can uncover whether the young orcas are some kind of breakaway group, which is forming their own behaviour.

That could probably be clarified by putting electronic tags on them, it reads. But the sailors do not have the patience to wait for that.

Bleach, electricity, and cannon fire

In groups on Facebook and WhatsApp, the impatience grows day by day, as well as the frustration over the authorities not doing anything.

The battle is raging between environmentalists who argue that the sea is the home of orcas, and more extreme of the sailors who have started using fireworks to scare away the troublemakers.

Fireworks appear—unofficially—to be the only effective deterrent method, but it is illegal and can lead to heavy fines, because the orcas are peaceful and loud noises risk damaging their hearing.

It must be said that cannon shots, known as seal bombs, are commonly used by American authorities to scare orcas away from oil spills. However, they are detonated at a long distance.

But sailors are struggling and attempting other methods.

Some have hung chains down along the rudder, others are working on the rudder giving the animals a jolt. Some sailors use bleach. Some are frantically banging on poles submerged in water, others are blaring their foghorns, and Alfred Lopez has confirmed to Ingeniøren that engineers are now working with authorities on deterrents that use underwater sound but will not reveal details yet.

However, David Lusseau is not sure that it is a good idea to make too much noise:

“We have to remember that we are not dealing with rabbits. These are large, intelligent animals that seem to seek out the interaction. If they like the thrill, then more noise just risks aggravating them. We also don’t use noise and foghorns when we meet a black bear, but initially try to move away quietly.”

There have also been several examples of orcas leaving a sailboat after an attack only to return as soon as the engine was turned on.

Sand in the water

However, a very simple trick seems to be gaining ground among sailors—sand. Spanish fishermen have succeeded in scaring animals away from their nets by throwing sand into the water. This inspired a Swedish couple to bring 75 kg of sand on their sailing trip along the Portuguese coast.

Dear readers. Before my sailing trip to the Mediterranean, I painted the lower part of my rudder white with room for a “work of art” that should scare away any orca. But what should I draw? Feel free to send a drawing to Teknologiens Mediehus, Kalvebod Brygge 33, 1560 Copenhagen V, email to, or share your ideas in the debate section.

In the spring/summer, Ingeniøren’s reporter Thomas Djursing will sail along the Spanish and Portuguese coasts and is open to ideas on what to paint on the rudder to scare the orcas away. Illustration: Thomas Djursing

Helena and Frederik Norberg were attacked by orcas on 27 October south of Lisbon while sailing in their 15-ton Colin Archer boat. Seconds after they spotted the first fin, the orcas began hammering into the rudder, but the pair began pouring sand out the back, and the orcas disappeared within a minute.

Whether sand works by annoying the orcas, or the pair were just lucky, it is too early to say.

And meanwhile, other sailors are getting new ideas, such as painting the rudder in discouraging colours.