A single killer whale killed a great white shark in less than two minutes. Scientists say this could be a sign of ecological change

(CNN) — A pair of killer whales working together have been killing white sharks off a stretch of the South African coast since at least 2017, plundering the sharks’ nutrient-rich liver and throwing away the rest.

Scientists are trying to understand the hunting approach that has driven sharks away from parts of the coast around Cape Town, and now research has revealed a surprising new twist in the behavior that could mean what for the marine ecosystem. Might give clues about it. General.

Scientists last year watched how one of the hunters, a male orca known as Starboard, single-handedly killed a 2.5-meter-long juvenile white shark over a two-minute period.

“Over two decades of annual trips to South Africa, I observed the profound impact these killer whales have on the local great white shark population. Dr. Primo Micarelli, a marine biologist at the Center for Shark Studies and the University of Siena in Italy, who was aboard one of the two ships, said, “It was unforgettable to see a great white shark passing by our boat to starboard ” Investigators observed the attack.

“Despite my fear of these predators, I am concerned about the balance of coastal marine ecology,” Micarelli said in a statement.

It is not unprecedented for orcas, highly intelligent and social animals, to individually hunt larger animals. However, researchers report in a study published this Friday in the African Journal of Marine Science that this is the first incident of its kind involving one of the world’s largest predators, the Great White Shark.

The starboard kill stands in contrast to more widely observed cooperative hunting behavior among orcas, which can corner larger prey such as sea lions, seals and sharks, and use their combined intelligence to attack, lead author Alison Towner said. And can use strength., doctoral researcher at Rhodes University.

According to the study, two to six killer whale attacks on white sharks were previously observed and they lasted for two hours.

“This sighting revealed evidence of solo hunting by at least one orca, challenging the traditional cooperative hunting behavior known in the region,” Towner said. Study. statement.

“These are unprecedented insights into the predatory behavior of this species,” he said. “The presence of these shark-hunting killer whales is likely related to broader ecosystem dynamics. “The rapid progress in this phenomenon has made it difficult for science to keep pace.”

The incident detailed in the study occurred on June 18, 2023, about 800 meters (875 yards) off Seal Island, near Mossel Bay, about 400 kilometers east of Cape Town, where people aboard two boats were observing the orcas. . ,

Less than an hour after arriving, a shark appeared near the surface, and researchers, tourists, and others on board the ship watched as Starboard grabbed a shark’s left pectoral fin and in less than two minutes “The shark pursued him several times and eventually swallowed him”. According to the study.

According to the studio, Starboard was later photographed with “a piece of bloody peach-colored liver in his mouth” from one of the ships. The male mate to starboard, port, was seen about 100 meters (328 ft) away when the murder occurred and did not participate.

In June, the carcass of a second great white shark washed ashore near Hartenbos, South Africa.

In June, the carcass of a second great white shark washed ashore near Hartenbos, South Africa. Christian Stopforth/Drone Fanatics SA

The pair are well known among the study’s authors and have been involved in hunting and killing great white sharks for many years. Orcas’ dorsal fins curve in opposite directions: the inspiration for their name.

Both cover huge distances along the east coast of South Africa until reaching Namibia. Researchers suspect that they began targeting great white sharks in 2015. By 2022, aerial footage would be the first to capture a killer whale killing a great white shark, Towner said.

“Although we don’t have strong evidence about specific factors, the arrival of the killer whale pair may be related to broader changes in the ecosystem,” Towner said. “It is clear that climate change and human activities such as industrial fishing are placing pressure on our oceans. To fully understand these dynamics, additional research and funding are necessary.

“There are still many unanswered questions about these shark-hunting orcas and where they come from.”

Killer whales are driving out large populations of white sharks, but researchers don’t know where the sharks are moving. “As they migrate, they could deplete intensive commercial fisheries,” Towner said.

The distinctive smell of shark liver in the air and seagulls diving towards a spot on the water’s surface, as well as the carcass of a second 3.55 meter shark found nearby, led onlookers to believe that another great white shark had been spotted before the ships. Must have been killed. arrived that day, investigators said.

According to the study, the kill by a lone killer whale would have been possible due to the small size of the prey, which was a juvenile white shark. Adult white sharks have a maximum length of 6.5 meters (21.3 ft) and a weight of 2.5 tonnes.

The study suggested that the intensity of the attacks may reflect the starboard’s skill and efficiency as a hunter, which may be a response to the stress of spending time hunting near shorelines in areas where humans are abundant. .

“We can’t predict whether this orca has become more sophisticated, but the rapid duration in which it killed the shark shows incredible skill and ability,” Towner said by email.

The livers of white sharks are huge organs, accounting for about a third of their body mass, and are rich in lipids, and killer whales discard the remaining carcass: a selective feeding behavior similar to that seen in seals, grizzly bears and wolves. Known among other carnivorous people. , according to the study.

“The observations reported here add further layers to the fascinating story of these two orcas and their abilities,” said Dr. Simon Elven, founding director and senior scientist at Sea Search Research and Conservation and a researcher at Stellenbosch University in South Africa. An announcement.

“As intelligent, apex predators, killer whales can quickly learn new hunting techniques on their own or from others, so monitoring and understanding the behavior used by other killer whales here and in South Africa will help us learn more about them.” An important part of helping understand. “Animals,” added Elven, who was not involved in the investigation.

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