The recent “attacks” by killer whales on pleasure boats off the coast of the Iberian Peninsula could be due to a curious “butterfly effect”: an unpredictable succession of cause-effect relationships that also involves another well-known marine species: the bluefin tuna.
A new explanation. A report prepared by the International Whaling Commission has postulated a new hypothesis to explain the behavior of the “Gladis killer whales” that we have witnessed in recent years. The explanation would be in the recovery of bluefin tuna populations (Thunnus thynnus).
Gladys. The incidents between orcas (Orcinus orca) and boats gained popularity last year but have been recurring since 2020. These incidents number in the hundreds and several of them have resulted in sunken boats.
Gladis is the name by which she is known. fifteen copies residents in the Atlantic, near the coasts of the Peninsula (or something like a surname, since the individuals of this group are known by names such as Gladis blanga, Gladis gris, etc.). Since the attacks became known, many experts have tried to explain this singular behavior.
Tedium. According to this hypothesis, the chain of reactions would have started with the limits imposed on the capture of bluefin tuna, a species considered in certain risk of extinction (although not considered vulnerable or in danger). These measures would have achieved the recovery of the species in recent years.
This is where orcas come into play. Bluefin tuna is one of its usual prey. The more tuna, the easier it is to hunt them, therefore less time spent looking for food… and more free time.
Free time that young specimens would be dedicating to exploring their environment and playing. Of course, the exploration and play of an animal between 3.5 and 6 tons of body mass can be dangerous to anyone who crosses their path. And that is what would be happening with these boats.
Attacks? Talking about “attacks” would therefore be inaccurate since these incidents between orcas and boats would simply be due to curiosity and not to any form of aggression on the part of the animals. “It’s a dangerous game they play, obviously,” explained to Washington Post Naomi Rose, co-author of the report. “But it’s a game.”
Fashions among orcas. Repeated social behaviors are common among orcas. In other words, these marine mammals have fashions like humans. have been documentedfor example, groups of orcas that “play” by launching porpoises (Phocoenidae) youths. In the 1980s, reports of orcas carrying dead salmon “as a hat” became popular.
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Image | Renaudstephanis, CC BY-SA 4.0
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