Why are the Iberian Orcas Sinking Boats, and How Can Tourists Safely Sail in the Region Again?

Since 2020, a string of highly unusual events has captured global attention: orcas attacking and sinking boats off the Iberian Peninsula. What began as a rare occurrence has evolved into a complex behavioural puzzle, one that raises questions not only about orca cognition, but also about their welfare and relationship with human activity.

On May 4, 2023, three orcas sank a yacht in the Strait of Gibraltar, and on September 13, 2025 another group sank a yacht near Lisbon, the fourth documented sinking. These incidents, which typically involve targeted attacks on boat rudders (especially of monohull yachts), have become more frequent and exhibit clear signs of deliberate strategy and social learning.

What’s behind the behaviour?

Researchers have proposed two main hypotheses:

1. A Social Game

   • Similar to how other orca populations have developed quirky, socially shared behaviours (such as wearing dead fish like hats or pushing marine mammals onto shorelines), this could be the latest in a long line of orca play. Juveniles are often the innovators, and behaviours, especially playful or exploratory ones, can spread rapidly through social learning.

2. A Stress Response

   • Some think that the behaviours may stem from negative past experiences, such as boat collisions or fishing gear entanglement.

Nobody knows for sure why the orcas have suddenly started showing these behaviours. It is our opinion at Animal Welfare Expertise that they are a form of play, where a few original orcas worked out that they could break rudders easily, and have continued doing it.

Regardless of the origin, the pattern is striking: orcas approach from behind, bite or ram into the rudder, and scrape the hull, sometimes resulting in mechanical failure and, in a few cases, the boat sinking. These events reflect not just high intelligence but remarkable coordination, suggesting both intentionality and social communication.

Photo credit Andre Estevez

The welfare angle

The ramming of rudders and boats in itself could seriously injure the animals, although humans can’t prevent this save from stopping all sailing boats entering the region.

In addition, the Iberian orca subpopulation is endangered, and their welfare is already compromised by:

• Heavy boat traffic and underwater noise pollution

• Reduced prey availability, particularly bluefin tuna

• Potential negative impacts from tourist or fishing boat interactions

What can be done to protect the orcas?

This phenomenon underscores the cognitive complexity of orcas and the importance of interpreting behaviour through a welfare lens. It also highlights the growing need for coexistence strategies including:

• Modified boating practices in high-risk zones

• More research into the behavioural ecology of this subpopulation

• Protection measures that prioritise orca welfare while ensuring human safety

Photo Credit: Adam Ernster

How can tourists safely sail in the region again?

Ultimately, the orcas are wild animals and we can’t stop them from interacting with boats. However, there are some mitigation measures which might help, some of which we can already do now, such as:

• Avoiding known orca activity areas or times

  • E.g. Authorities and research groups have issued warnings for boating in certain zones at certain times (e.g. near the Strait of Gibraltar, Gulf of Cádiz) 

  • Use maps / apps or local tracking data to know where orcas are known to be.

• Distance and course adjustments

  • Keep a reasonable distance (2-3 km) away from orcas when detected. If you see orca pods, change course and move away.

  • Despite mixed advice, it seems sensible to not reduce speed, as this allows the orcas to more easily ram the rudder or stern. That said, don’t increase speed or make erratic movements as this would put the orcas at risk.

• Avoid provoking the orcas’ curiosity

  • Minimise noise, engine revving, or other actions that might attract orcas’ curiosity (shadows, prop wash, things dangling from boats).

  • Avoid confrontational responses (it may be that banging hulls or using deterrents could escalate behaviour).

If these mitigation strategies don’t work and the orcas continue interfering with boats over the next few years, it may be that to sail in the region yachts will be forced to use:

• Reinforced boat design/rudder protection

  • Reinforcing rudders, using more robust rudder materials or designs less susceptible to damage. Some sailboat owners are investigating stronger rudder stocks or protection shielding.

  • Design changes to stern/hull that offer less leverage or vulnerability to orca attacks.

• Early warning systems

  • Local authorities will likely have to establish systems that use a combination of social media reports, marine mammal observer networks or apps to share sightings in real-time. If off-shore controllers or authorities can alert sailors when orcas are nearby, sailors can take precautions.

Concluding thoughts

While these interactions are likely a case of playful curiosity, they reveal a great deal about orca intelligence, and our evolving responsibilities in managing our impact on wild marine mammals. Researchers are continuing to investigate, but if it is indeed a play behaviour (and therefore inherently reinforcing for the animals), it will likely not stop. We will therefore have to modify our own behaviour if we want to continue sharing these waters safely with the orca!

Photo Credit: Dianne Maddox