Researchers are sounding the alarm after a disturbing phenomenon appeared along South Africa’s coastline: great white sharks – once the area’s dominant creature – are now appearing on the coast and, in some areas, disappearing entirely.
What happened?
Great white sharks, often seen as unstoppable ocean predators, are quietly retreating from parts of the South African coast. People first pointed to fishing or boat activity, but researchers noticed that two orcas named “Port” and “Starboard” appeared to be driving the sharks away from their usual haunts, ScienceAlert reported.
Since 2017, researchers have documented at least nine great white sharks found dead along shorelines after their livers were removed. Orcas target the nutrient-rich organs with precision, killing the shark quickly.
Marine biologist Alison Towner, who led the study, said this behavior forced the surviving sharks to flee.
“However, what we appear to be seeing is a large-scale avoidance (as opposed to small-scale) strategy, similar to what we see used by wild dogs,” she explained on ScienceAlert. “The more frequently orcas visit these locations, the longer great white sharks stay away from these locations.”
The effect is very significant. Areas once known for reliable great white shark sightings, including the waters off Dyer Island, have now seen their sightings decline dramatically – sometimes disappearing for months at a time.
Why is the decline of great white sharks a concern?
Great white sharks play a vital role in maintaining the balance of marine ecosystems. As apex predators, they help regulate populations of small sharks and fish.
When great white sharks retreat, something else takes their place. Copper sharks are appearing more frequently in parts of the South African coast, changing which species are hunted and which are not. This shift tends to affect smaller fish first, especially those that are already under stress.
The aftermath will not stay at sea. Shark sightings help bring tourists, researchers and regular revenue to nearby towns. As sightings dwindle, so does activity, leading to fewer visitors in some coastal communities and less support for marine conservation.
Ecologists warn that marine systems are more stable when top predators remain part of the ecosystem. Without them, things may take longer to resolve—if at all.
What measures are being taken?
Researchers continue to track the predator’s movements through tagging and aerial surveys to see if the great whites return. So far, the changes appear to be continuing.
For those following this story from afar, it’s important to avoid putting additional pressure on ocean ecosystems—from focusing on where seafood comes from to reducing the plastic that ends up in the ocean.
What is happening on the South African coast is not isolated. Oceans don’t rebalance overnight when dominant species disappear. It adapts—sometimes smoothly, sometimes not—and the consequences can be far beyond the water mark.
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