By Alex Mitchell
How the tides have turned.
An unlikely pair of culprits have been scaring great white sharks away from the coast of South Africa for years, according to scientists who began noticing the absence of the dreaded apex predator along the country’s Western Cape — known as the global “Great White Capital” — back in 2017.
What was first suspected to have been caused by human activities such as overfishing has now been pinned on something else entirely. According to new research, it’s a particularly vicious pair of orcas, or killer whales.
Not only are they slaughtering the great whites en masse — eight carcasses have washed ashore since 2017 and many more deaths are suspected, per the latest reports — but the orcas are also tearing apart their prey to get at the hearts and nutrient-filled livers.
“What we seem to be witnessing is a large-scale avoidance, mirroring what we see used by wild dogs in the Serengeti in Tanzania in response to increased lion presence,” said study lead and marine biologist Alison Towner.
The mass exodus is encouraging a new mesopredator — the bronze whaler shark, which is known to be eaten by the great white — to flood the area, only to run into the apparently insatiable interlopers.
“These Bronze Whalers are also being attacked by the Orcas too, who are indicating a level of experience and skill in hunting large sharks,” Towner said.
The deadly crimp in the food chain spells out potential long-term damages for the ecosystem, Towner warns.
“Balance is crucial. With no great white sharks restricting Cape fur seal behavior, the seals can predate on critically endangered African penguins, or compete for the small pelagic fish they eat,” she said. “There is only so much pressure an ecosystem can take, and the impacts of orcas removing sharks are likely far wider-reaching.”
