New study
Orca pair drives away and kills great white sharks in South Africa
A pair of orcas chases away and kills great white sharks in South Africa. Photo: Simon Elwen/dpa
© dpa-infocom GmbH
In the meantime, the sharks are reluctant to be seen in the area. According to researchers, the unusual behavior of the killer whales could have something to do with the worldwide loss of species.
In South Africa, a pair of orcas kills great white sharks or drives them out of their natural habitat. According to a study published in the African Journal of Marine Science, great white sharks are now fearfully avoiding the coastal area around Gansbaai, previously considered one of the most legendary areas in the world for sighting the giant predators.
Since 2017, eight great white sharks have washed ashore in the region after an orca attack, according to the study. Seven of them were missing their livers, and some were missing their hearts – wounds clearly inflicted by the same orca couple. Researchers suspect it also killed other great white sharks that didn’t wash ashore. Orcas (killer whales) are distributed worldwide and feed on fish and seals, among other things.
The results of the study, which began in 2017, indicate that the attacks have triggered a rapid and long-term mass displacement of great white sharks. Great white shark sightings in Gansbaai have “decreased dramatically” since 2017. Gansbaai is located in South Africa’s Western Cape Province. The place attracts tourists from all over the world who want to see great white sharks from dive cages.
“We’re observing a large-scale avoidance strategy… The more orcas visit these sites, the longer the great whites stay away,” said study lead author Alison Towner. The absence of great whites is unprecedented in the region and is transforming the marine ecosystem, Towner said. Fewer great white sharks, for example, led to greater numbers of Cape fur seals. This has a negative impact on the endangered African penguins that the seals hunt.
Data that has not yet been published indicates that the presence of orcas, also known as killer whales, is increasing in the coastal regions of South Africa. It’s thought the pair of orcas could be a special shark-eating species that prey on at least three species of sharks. The changes in hunting behavior may be related to a decline in various fish populations that were previously prey for orcas, Towner said.