In South Africa, a duo of killer whales make short work of great white sharks. A behavior that threatens the balance of local ecosystems.
Jaws vs. Orca.
Outstanding hunters, intelligent, impressive… Orcas reign supreme over the oceans of the whole world. Since 2017, a pair of killer whales has been attracting the attention of researchers. The reason ? Predators have taken to killing great white sharks off the coast of South Africa, claiming their territory.
Photo credit: Istock
Eight sharks killed
In any case, this is what a new study published on June 30 in the African Journal of Marine Science confirms, specify our colleagues from the Huffington Post. According to the document, sharks have deserted parts of the Gansbaai coast since the arrival of marine mammals.
A total of eight great white sharks have washed up on shore following an orca attack, details the news site. Scientists believe the toll could be higher.
Photo credit: Marine Dynamics / Dyer Island Conservation Trust / Hennie Otto
This massacre resulted in a drop in visual sightings of great whites in some bays in the Western Cape, notably in Gansbaai. This place is known for observing large predators.
According to Alison Towner, a biologist at the Dyer Island Conservation Trust, sharks tend to flee when they sense the presence of a nearby marine predator: “Initially, following an orca attack, individual great white sharks do not appear for weeks or months”.
Killer whale behavior intrigues researchers
And the least we can say is that the behavior of the two cetaceans intrigues scientists. Killer whales might simply enjoy shark meat, researchers say. For her part, Alison Tower explains that diet could also “be linked to a decline in prey populations, leading to changes in their distribution pattern”.
Photo credit: Istock
Unsurprisingly, the disappearance of sharks has a strong impact on the balance of local ecosystems: “This triggered the emergence of a new mesopredator in the area, the bronze whale shark (Carcharhinus brachyurus)”.
“To put it simply, although this is a hypothesis for now, the pressure an ecosystem can sustain is limited, and the impacts of killer whales killing sharks are likely to be much more widespread. »conclude the scientists.