An interview with one of the world’s leading cetacean researchers – Renaud de Stephanis
In the wake of orca ”attacks” between Brest and the Strait of Gibraltar, I followed the recommendations of orcas.pt to make a safe passage through ”orca alley”. Besides lessons learned from the experiences of other sailors, there have been many hours of research behind these recommendations. Last December (2023) I went to Tarifa, in Southern Spain, and visited Renaud de Stephanis from CIRCE, who collaborates with orcas.pt. I joined his team on research vessel Sea Observer for a day of work in the Strait of Gibraltar and asked a lot of questions:
How did you meet and team up with Rui Alves from orcas.pt?
Rui started the group on WhatsApp (that is now on Telegram, a similar app, without restriction for the number of participants in one group), and I became one of the first people in the group. I found it via Facebook. Rui and I agree on how to approach the orca situation and our work together has been spontaneous. Nothing planned or formally organized.
How long have you been working with the orcas in the Strait of Gibraltar?
In 1996 I saw the first orca, but, unfortunately, it was a dead orca. In 1999 I saw a live orca for the very first time. I have studied orcas since then in the Strait of Gibraltar, in Greenland and in the Crozet archipelago in the Southern Ocean.
How and when did orcas attacking boats become a part of your work? What were your first thoughts?
It didn’t happen from one day to another, but it was rather a fluid process. When, in 2020, there was the first mention on social media of an orca ‘’attacking’’ a yacht, we expected that it would create a big problem, because it was hyped a lot, and we were afraid that a lot of disinformation would come from this, that could damage the orcas. But previous to that, between two and five orcas were already interacting with boats. In the beginning they were just staying behind the propellor of boats, seeming to enjoy the bubbles or vibration, so it was not so surprising that they extended that behaviour into playing with the rudder. I believed that it would be best if we could stop this orca behaviour, before it turned into a larger problem. My first thoughts were the same as they are still now; it is a three-step strategy – yachts should avoid the orcas, the effects of the ‘’attacks’’ should be reduced and the behaviour of the orcas will change as a consequence.
Apart from the research that you are working on, you are working with the sailing community and orcas.pt. Is this helping your work?
Yes, it helped to test if my three-step strategy is a feasible solution to the orca ‘’attacks’’ and I think I can say by now that it is, although it still needs to be promoted to as many sailors as possible. Apart from that, the information that we get out of the Telegram groups, helps us to test hypotheses. Also, the key is that we can inform the group about the location of the orcas, to enable the sailors to avoid them.
Are you a sailor yourself? You have done so much to help the sailing community. Other researchers may care only about their objects of study. Why do you care enough to help us sailors?
I have sailed on Optimists and catamarans, but I prefer windsurfing and kitesurfing. We have 4 research boats, all motorboats. I have always been friendly with sailors and happy to help them. And I love cetaceans. By working together, both sailors and orcas will benefit.
Recently you were granted the Ocean Award 2023, together with Rui Alves from orcas.pt. How does this award influence your work?
It has helped our work by making increasingly more people believe in what we do. This way we can educate more sailors to follow our advice and solve the problem.
Why do you think the orcas are ‘’attacking’’ yachts? What have been previous theories that have been discarded?
It is playful behaviour, the orcas may behave in a similar way to sunfish or plastic or tuna, in this case, the result of the rudder breaking is a ‘’reward’’ of their behaviour – something happens. Do you have children? If you ignore a certain behaviour, they will often stop doing it because it takes the fun away. Of course, to the sailors it does come as an ‘’attack’’ when the rudder gets broken, but it is not aggressive behaviour on behalf of the orcas. A lot of reasons have been speculated about, especially on social media, but we shouldn’t forget that orcas are animals and that they behave as such. With a social structure and relationships and copying each other’s behaviour.
What are potential solutions that you have already discarded and what solutions do you plan to research this year?
Pingers do not work, we tested with them and, if anything, they attracted the orcas. People have sadly used firecrackers, but these are illegal, and the orcas are a protected species. Sand does not do anything. Going around in circles doesn’t help at all and stopping is a guarantee for a broken rudder. The current guidelines on orcas.pt work. And we have tested with spikes on the rudder. This seems to have promising results and we will use this on our boats. We hope more boats will try this, so we can learn even more.
Besides more information about spikes, and continued information about the orcas’ location, what can we expect from you in the near future?
We are working on a short educational video to teach sailors how to avoid the orcas and what to do in case they encounter them. When it is ready, you will be able to find it on orcas.pt.
Why are sailing boats most affected? Does size matter? Or speed?
We have done experiments always with a motorboat and we have broken many rudders so far. But motorboats seem to report less incidents. Also, sailing boat rudders are longer, so the pressure exercised by the orcas on a sailing boat rudder will result sooner in breaking it, than that on a shorter, motorboat rudder. Size does not matter. Speed does. The orca breaks the rudder by putting pressure on the edge of the rudder. If the boat is laying still, the pressure will be larger. But if the boat is moving, the faster it moves, the smaller the pressure becomes on the rudder. This is why we recommend leaving the area as fast as possible if you encounter orcas. They will typically follow you for two kilometres and then they will return to their group.
The reason to leave quickly when orcas are spotted is not just to flee, but especially to make it harder for them to break the rudder. Is that what you just described?
Yes, like I said before, it is a straightforward calculation of the ‘’angle of attack’’ – physics.
A lot has been speculated about hull colour, what can you say about this?
Orcas, like dogs, see only black and white. Therefore, it makes no sense at all to discuss about blue, green or red anti fouling.
What senses do orcas use?
They use echolocation, sight, touch, and hearing via the vibration in the water.
I understand that you have destroyed quite a few rudders while doing experiments to find out what sailors should do and what they shouldn’t do? Who is paying for all this?
Yes, during our experiments we have destroyed six rudders, the first two were paid by our insurance company, but then they told us that that was enough. After that, the orcas destroyed 30 dummy rudders. Our research is funded by the Spanish ministry of environment.
Is it true that you have tagged some orcas with a location beacon?
Yes, we have tagged six orcas, but these tags currently do not work anymore. We plan to tag the orcas again though. Not all of them, there are between 62 and 64 Iberian orcas. We cannot pass the information directly, so that sailors can pick it up, but we will continue to work with the maps in orcas.pt to let you know where the orcas are and where you can avoid them.
Is it true that orcas do not like pilot whales? Can we not imitate to be a pilot whale somehow?
The pilot whales in the Strait of Gibraltar are aggressive to the orcas. If boats try to imitate pilot whales, this could also make the orcas aggressive. Besides that, each species has their own ‘’home territory’’. If yachts start imitating pilot whales, it will confuse the sense of direction of the orcas. The orcas are a protected species and our three-step strategy that you and many other sailors are currently following is working.
It’s supposed to be ‘’safe’’ shallower than 20 meters and deeper than 350. But in the summer the orcas migrate to Biscay. When they are ‘’travelling’’ is the risk of attack lower?
This is not data that we have provided, but something that has come from Facebook. We only ever recommended a certain distance from the coast. Also, there is no orca migration. Their home is between the Bay of Biscay and the Strait of Gibraltar. They go to places within that home to find their food, the tuna, when and where they know they will find it. But the risk of attack in the Bay of Biscay is low.
Do you expect there are going to be any unpleasant rules for pleasure craft as a result of the orca situation?
No rules for pleasure craft are expected for as far as I know.
CIRCE is part of a large EU project for maritime environmental conservation. As a sailor, I love the sea. Is there anything you can recommend sailors who would like to contribute to marine conservation too?
Yes, do not stop if you see orcas and avoid the area where they are expected to be. This is what you can contribute to marine conservation. The orcas did not have this behaviour before. And this is how we can hopefully end it again.
This article has appeared in the August 2024 issue of:
With special thanks to:
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All images are a courtesy of CIRCE and orcas.pt