A whale watcher from Monterey, Calif., Recorded a large group of dolphins jumping from several hungry orcas.
The great white shark may not be the greatest predator in the ocean, after all.
In a poll published in the journal Nature, scientists found that white sharks not only fled killer whales when they arrived at a marine sanctuary near San Francisco, but were released until next season.
"When confronted by killer whales, white sharks will immediately vacate their preferred hunting spot and will not return for up to a year, even though orcas are just passing by," said Salvador Jorgensen, a researcher at the Monterey Bay Aquarium and lead author of the study. the study.
Minutes after killer whales appeared to feed on elephant seals, researchers said that white sharks began swimming in the sea or crowding into other colonies of seals furthest along the coast.
Some of the white sharks that usually dominate the sanctuary extend over 18 meters in length, said Monterey Bay Aquarium scientist Scot Anderson.
22 feet: Divers in Hawaii may have swum with the largest white shark ever recorded
Pollution: Pregnant whale with almost 50 pounds of plastic in the stomach found dead in Italy
Researchers compared electronic tag data for shark tracking and field observations of orcas sightings. Predators are not usually found in Greater Farallones National Marine Sanctuary, researchers said, because killer whales occasionally visit the area, while white sharks often gather for more than a month each fall.
Marine elephants also benefited from the interaction, the study found, suffering from four to seven times fewer attacks in the years the white sharks fled. The researchers analyzed 27 years of research on seals, orcas and sharks in the area, plus 165 white sharks scored between 2006 and 2013.
"After the orcas show up, we do not see a single shark and there are no more deaths," Anderson said.
The study did not conclude whether these orcas hunted white sharks or intimidated their competition, but Jorgensen said the research shows how interactions between major predators affect food chains.
The dynamics among marine predators is more difficult to observe than those on land, he added, noting that it may take longer to understand the relationship between orcas and white sharks because they meet so rarely.
"We do not normally think about how fear and risk aversion can play an important role in the formation of large predators that hunt and how this influences ocean ecosystems," said Jorgensen. "It turns out that these risk effects are very strong even for large predators such as white sharks – strong enough to redirect their hunting activity to less preferred but safer areas."
Read or Share this story: https://www.usatoday.com/story/news/nation/2019/04/16/great-white-sharks-flee-orcas-study-shows/3491295002/