In 2017, an unusual event unfolded along the shores of South Africa. A small female great white shark mysteriously washed up with no evident signs of human interference, leaving marine biologists puzzled. This incident marked the beginning of a significant decline in the great white shark population in Gansbaai, a region once known as the great white shark capital of the world. By 2022, sightings of these majestic predators had dwindled to alarming levels, raising concerns among scientists and conservationists alike.
The absence of great white sharks in South Africa coincided with a dramatic increase in their primary prey, including cape fur seals and bronze whaler sharks. This ecological shift hinted at a deeper mystery. In 2022, a breakthrough came when a drone captured footage of five orcas attacking a three-meter-long white shark. The orcas displayed a chilling hunting technique, biting between the shark's pectoral fins and extracting its liver. A helicopter crew confirmed three more kills on the same day.
The orcas responsible for these attacks were identified as two male orcas, named Port and Starboard, who had been frequenting Gansbaai since 2015. These apex predators terrorized the great white shark population, leading to their dramatic decline. Dr. Alison Towner, a marine biologist, examined four shark carcasses, each missing its liver. This gruesome discovery highlighted the orcas' precise hunting strategy.
“Witnessing the very predator I’d dedicated my life to studying wash up dead on the beaches was surreal, and something I will never forget,” – Dr Alison Towner
The ramifications of the great white sharks' disappearance extended beyond the marine ecosystem. With fewer sharks to keep their populations in check, seals began to flourish along South Africa's coastline. This boom in seal numbers resulted in increased predation on African penguins, further disrupting the delicate balance of nature.
“The only element missing was direct observation of an attack,” – Dr Alison Towner
A study led by Professor Nicholas Dulvy revealed that the great white shark population in Gansbaai had declined by half since 1970. The broader implications were concerning, as overfishing continued to claim over 100 million sharks annually worldwide. More than a third of shark species now face extinction threats.
“After more than a decade of work, we now know that global abundance has been halved since 1970,” – Dr Nicholas Dulvy
The great white sharks' exodus from Gansbaai also affected Mossel Bay, where their numbers similarly dwindled. The situation worsened in June 2024 when seals in the Western Cape became infected with rabies, with the epidemic reaching Mossel Bay by July.
Esther Jacobs, founder of the marine conservation charity Keep Fin Alive, emphasized the precarious future facing sharks if overfishing persists.
“To witness one of the ocean’s top predators defeated so easily was heartbreaking,” – Esther Jacobs
“The future of sharks looks bleak if overfishing continues,” – Esther Jacobs
“It was both awe-inspiring and harrowing. Starboard’s immense power was on full display as he gripped the shark firmly, even while it thrashed around,” – Esther Jacobs
“We watched in stunned silence as he eventually eviscerated the shark,” – Esther Jacobs
Dr. Alison Towner highlighted the need for scientific insights to guide conservation efforts.
“That is, of course, if science is listened to,” – Dr Alison Towner