In the waters of the Gulf of California (Mexico), a little-known natural scenario unfolds on the surface. A pod of killer whales he had already been spotted hunting whale sharks and manta rays impress not only with their strength, but also with their strategy in hunting another large fish: white sharks. Feared predators of the oceans, they suddenly seem vulnerable to these cetaceans, the only ones capable of dominating them in an interaction rarely recorded in the area.
To the group to which he also belongs Montezuma – a well-known male orca who was photoidentified in 1988 on the island of Ángel de la Guarda – specialized in capturing less experienced juvenile specimens to escape as adults do. The new study, published this Monday in the magazine Frontiers in marine sciencesdetails how orcas throw prey onto their backs to induce a state of temporary paralysis known as tonic immobility, facilitating extraction of the energy-rich, highly nutritious liver.
“We suggest that young white sharks could be, if they are not already, a seasonal prey for these killer whales,” Conexiones Terramar project director Erick Higuera, lead author of the research who has dedicated himself to observing and photographing marine life for three decades, tells EL PAÍS. The first sighting occurred in 2020, when a group of five orcas led by a matriarch were filmed attacking a white shark about two meters long.
Images captured with drones show how the capsule manages to tear out the organ and share it with its companions, including pups, releasing jets of bubbles to keep curious sea lions at bay. Two years later, a second search of the area also revealed the same thing pod of killer whales attacking another young specimen.
On that occasion some seagulls and pelicans also joined the banquet, pecking at the remains. When a shark is capsized, something in its body shuts down. THE Lorenzini vialstiny sensory receptors distributed all over the head and sides collapse. The specimens remain motionless, as if the sea had left them breathless. “The white shark does not have such thick skin, but it can still bite. The killer whale must ensure that it is not attacked during the hunt,” says the marine biologist.
The authors of the research point out that these images represent the first evidence of killer whales preying on young white sharks off the coast of Mexico. “Specialization in predation by killer whales in different areas it is important because sometimes you have a very complete vision of some areas, but very relaxed or empty in other areas of the world”, completes marine zoologist Carmen Arija, director of Sea Wolves, who did not take part in the observations.
Although it’s not behavior that the sea hasn’t shown before. Bruno Díaz, doctor in Ecology and founder of Bottlenose Dolphin Research Institutebelieves the recent publication “has similarities to studies conducted in South Africa.” This phenomenon has also been documented in Australia and California (United States).
“It doesn’t definitively confirm a hunting technique observed in this area, but it does reveal some similarities that, with more time and future research, could help us better understand how this behavior works,” he points out.
Díaz and his colleagues are carrying out similar work on the interaction of orcas with octopuses, but on the coast of Galicia. “It is the observation of specimens interacting (playing and biting) with the prey, which is an indication of a potential food preference for it,” indicates this expert, who did not participate in the recent study.
a seasonal dam
The authors believe that changes in the distribution of white sharks in the Pacific could have presented an opportunity for killer whales. Climate events such as El Niño appear to have altered the white shark’s breeding grounds and increased its presence in the Gulf of California. Each new generation of young, inexperienced and vulnerable people becomes easy prey.
“Then it is easier to catch a juvenile. It will not run away, it will not warn others that they have attacked a companion. In the Farallones Islands, off the coast of San Francisco, we have seen how adults react, because as soon as they perceive danger, they disappear,” explains Erick Higuera. For the scientist, the white shark today faces too many threats: accidental fishing, climate change and, we now know, natural predation by killer whales.
Something similar happens in the fishing village of Gansbaaisouth-east of South Africa. There white sharks were seen daily, followed by teams of experts who patiently studied them, but something has changed. Marine biologist Carmen Arija, who monitors whales in the same area, acknowledges that the presence of white whales has plummeted. “In 2015, two male killer whales showed up and it hasn’t stopped since then. The scientists tracking them told us they hadn’t seen them there for almost a year,” he says.
The ocean map also moves. There is a movement towards the east and it is basically due to the fact that the orcas are coming from the south-west of the country and their prey are moving towards the south-east, changing their distribution area to avoid these two orcas.
Future research aims to reconstruct the life of the Gulf of California pod, identify its members, analyze vocalizations to determine dialect and measure how human presence may alter their customs. “We must continue to monitor the distribution ranges and aggregation sites of young white sharks, particularly those that now appear as a result of changes in water temperature and warming seas,” concludes Higuera.
