Orca Boat Attacks: Understanding the Iberian Phenomenon

Since 2020, sailors navigating the waters near Spain and Portugal have reported a startling trend. A distinct sub-population of orcas, also known as killer whales, has been systematically approaching sailing vessels and damaging them. These interactions have resulted in hundreds of damaged boats and several sinkings. Marine biologists are working urgently to understand if this behavior is aggressive, playful, or a response to past trauma.

The Pattern of Interactions

The incidents are concentrated around the Strait of Gibraltar, the Gulf of Cádiz, and the coast of Galicia. According to the Grupo de Trabajo Orca Atlántica (GTOA), or Atlantic Orca Working Group, there have been over 600 recorded interactions since May 2020.

The behavior is remarkably consistent. The orcas, usually a small group, approach the stern of a sailing yacht. They ignore the hull and focus entirely on the rudder. By ramming or biting the rudder, they often disable the vessel’s steering. In severe cases, the force applied to the rudder cracks the hull, causing water ingress.

A notable recent example occurred in May 2024, when the sailing yacht Alboran Cognac was intercepted near the Strait of Gibraltar. After the orcas damaged the rudder and hull, the crew had to be rescued by a passing tanker, and the yacht eventually sank. This marked one of several vessels lost to these encounters, joining others like the Grazie Mamma II which sank in November 2023.

Theory 1: The "White Gladis" Trauma Response

One of the leading theories comes from Alfredo López Fernandez, a biologist at the University of Aveiro in Portugal and a representative of the GTOA. He suggests the behavior may stem from a traumatic event suffered by a matriarch orca known as “White Gladis.”

The theory posits that White Gladis was likely struck by a boat or entangled in illegal fishing gear. This “critical moment of agony” may have triggered a defensive behavior where she began attacking the perceived threat: the boats.

Orcas are highly social and capable of social learning. López Fernandez argues that younger orcas imitated White Gladis. While the matriarch may be acting out of defense or trauma, the juveniles are learning the behavior as a skill or a cultural tradition. This explains why the behavior has spread from a single individual to a specific cluster of roughly 15 whales within the population.

Theory 2: The Fidget Spinner Effect (Play)

Not all experts agree with the revenge narrative. Renaud de Stephanis, president of CIRCE (Conservación, Información y Estudio sobre Cetáceos), proposes that this is likely a fad rather than a fight.

This theory relies on the intelligence and curiosity of the species. The Iberian orcas feed primarily on bluefin tuna. Due to conservation efforts, bluefin tuna populations have rebounded in the region. Consequently, the orcas spend less time hunting and have more “leisure time.”

According to this view, the rudder is simply a toy. When orcas push the rudder, the boat spins, which they may find stimulating or fun. It is comparable to a teenager playing with a fidget spinner. The orcas are not trying to kill the sailors or destroy the boat out of malice; they are simply engaging in rough play that unfortunately exceeds the structural limits of fiberglass yachts.

Supporting this theory is the fact that once the rudder is broken and the boat stops moving, the orcas usually lose interest and swim away. If they intended to harm humans, they could easily capsize the small vessels entirely, yet they do not.

Identifying the Whales

Researchers have identified specific individuals responsible for the majority of these interactions. The GTOA catalogs them using the nickname “Gladis.”

• White Gladis: The mature female suspected of starting the behavior.
• Black Gladis: Another adult female frequently involved in the interactions.
• The Paturro Brothers: Two juveniles often seen participating in the rudder breaking.

The sub-population of Iberian orcas is incredibly small, numbering fewer than 40 individuals. They are listed as Critically Endangered by the IUCN Red List. This makes the situation delicate; while sailors need protection, the loss of even one breeding female could doom the entire sub-population.

Safety Measures for Sailors

Authorities in Spain have issued various recommendations over the last four years. Initially, the protocol was to “stop and stay.” Sailors were advised to drop sails, turn off the engine, and leave the helm (steering wheel) loose to prevent injury to the skipper if the rudder was struck violently.

However, recent discourse has shifted. Some sailors and experts now suggest that motoring away in reverse or making the boat uninteresting is a better strategy, though this is debated.

A “safety map” app created by GTOA uses sighting data to help sailors avoid areas with high orca activity. Additionally, the Spanish Transport Ministry has periodically closed specific maritime zones to sailing vessels under a certain length to prevent encounters during peak migration months.

Frequently Asked Questions

Do these orcas attack people? No. There have been no reported cases of orcas attacking swimmers or sailors who have fallen into the water during these incidents. The aggression is directed solely at the vessel’s mechanics.

Why do they only target sailing boats? Sailing boats have large, exposed rudders that provide significant leverage when pushed. Motorboats usually have smaller rudders or different propulsion systems that are harder for the whales to manipulate.

Can acoustic deterrents stop them? Most research indicates that pingers or acoustic harassment devices are ineffective. Orcas are smart and quickly realize the noise is not a physical threat. Furthermore, excessive noise pollution can harm other marine life and is illegal in many protected waters.

When will this behavior stop? Biologists are unsure. Fads in orca populations (like the time a pod in the Pacific Northwest wore dead salmon as hats in 1987) often fade away naturally. However, because this behavior provides a tactile reward (the boat moving), it may persist longer than visual fads.