Since the 1975 movie "Jaws," beautiful white sharks are considered the most fearsome sea wrangers. But the new research published on Tuesday shows that this may not be the case.
When good whites are hunting for seals near the Farallon Islands from San Francisco that encounters whales killer, known as orcas, swimming, they immediately flee,, and will not return until next year , according to a study by researchers at the Monterey Bay Aquarium, Stanford University and Point Blue Conservation Science in Petaluma.
"After the orcas came out, we did not see a shark," says Scot Anderson, an expert on white shark at the Monterey aquarium.
Amazing hunters are great white sharks. They can grow up to 20 feet in length and weigh more than 4,000 pounds. But the killer whales are larger, growing up to 30 feet long and weighing 1
White sharks swim for 35 miles an hour – faster than the fastest man in the world, the Jamaican sprinter Usain Bolt, can run. But killer whales swim faster, stronger and bloody in groups, such as balloon packs. And they documented, from time to time, eating white sharks, including a famous incident in 1997 taken at the Farallon Islands. Two years ago, five dead white sharks were washed in South Africa, killed by orcas. Killer whales eat their rivers. "It's astonishing as you can not see a 17-foot shark swimming in a boat, with a larger predator, orca," says Sal Jorgensen, a white shark expert at the Monterey aquarium, while sailing in a boat on a video from Farallons that the aquarium was placed Tuesday on its website. "It's a little humble to see."
Jorgensen was the lead author of the paper, published in the journal Nature Scientific Reports.
From 2006 to 2013, he and other scientists from the aquarium and Stanford University white shark with a high-tech acoustic tag between Southeast Farallon Island, Tomales Point in Marin County and Año Nuevo Island in San Mateo County. They placed small tag tracking with a 10-foot pole and a small titanium dart.
Jorgensen and Anderson compared the behavior of sharks recorded in 27 years of records combined by researchers who see the elephants that seal, sea lions and killer whales on the Farallon Islands. The records were gathered by researchers at Point Blue Conservation Science, a non-profit group, and other organizations.
This study found it rare for killer whales to swim Farallons between September and December, when white sharks are present in large numbers each year to hatch seals. In fact, orcas had only 18 days in 27 years in those autumn and winter months.
But when the two scary predators overlap, the white sharks did not fade away. The hunters have become hunted.
In the best documented example, killer whales from two separate pods came to Farallons on November 2, 2009, when 17 previously tagged white sharks were present. Killer whales spend only two hours in the area. But the sharks are leaked. Seven of them swam 50 kilometers south of Año Nuevo Island, while others move to Tomales Point, 35 kilometers north.
None of the sharks came back until next year.
Similar examples of "sudden and consistent flight" of White sharks occurred in 2011 and 2013 when killer whales came to Farallons, researchers said.
Beneficiaries? Elephant seal and sea lion.
In a typical year, scientists watched about 40 elephant seals and sea lions eaten by good white near Farallon Islands from September to December. But that number was reduced by four to seven times over the years when white sharks fled orchids.
Although the interactions between large territorial predators have been studied for many years, little is known about how big pirate makers interact with the ocean. Scientists say that white sharks can escape because of fear they are eaten. They can also be harmed by killer whales, who also eat seals and sea lions.
"Basically, we do not think how fears and risks can have a role in digging where large hunters will be caught," says Jorgensen. "It appears that these dangers are very powerful even for large predators such as white sharks – sufficient enough to redirect their hunting activity to the preferred, but safer places."
Further research is required, he said. , the top predator on the Pacific Coast is not the "Jaws" monster, but the same species for years has made tricks in Sea World and other marine parks: the orca.