Opinion | The Disappearance of Great Whites from African Waters

The apex predators of our seas, known to grow over 6 metres long and weigh over two tonnes, have dominated our coastal waters for centuries. But recently they have vanished. Great white sharks are being spotted less and less in places such as Gansbaai and False Bay where they once thrived. Researchers are scrambling to discover what has chased them out and how it will affect the balance of our delicate ecosystems. But what could possibly threaten these creatures that have existed long before trees?

South Africa has existed as a prime shark-spotting destination since the 1990s, with over 120,000 tourists visiting Gansbaai and False Bay annually before 2019. In recent years this number has drastically dropped to below 30,000, the decline strongly affecting local economies. Cage diving and boat viewings were largely popular, but as of late, they have been replaced with bronze whalers and sevengill sharks. 

Between 2000 and 2015, Frontiers found that boat-based surveys recorded great white sightings at 1.64 per hour, whereas between 2017 – 2020 this figure dropped dramatically to 0.3 sightings per hour. Although signs appeared in 2015, researchers only took real interest in 2017, when shark carcasses washed up on shore.

Stunned biologists were baffled by the surgical nature of the shark’s cause of death. When initially performing necropsies on the sharks, scientists attributed the sharp slashes around the pectoral fins and missing livers to human activity; however, only after discovering what looked like bite marks they linked the attacks to orcas. 

Around that time, two particular orcas had been spotted near the sites where the carcasses were found. These two orcas would become known as the infamous Port and Starboard, recognisable by their collapsed dorsal fins. But why were they singled out? Well, orcas typically hunt in groups called ‘pods’, yet these two are a lonesome pair with a unique hunting style. 

Nevertheless, while their method of ambushing great whites and methodically only taking the nutrient-dense liver was new at first, they were certainly not the only ones as several other pods have been spotted following suit since 2017. Once these attacks started, there was a significant decrease in sightings suggesting the remaining sharks had fled our coastal waters. Yet as the years went on, one thing has continued to puzzle scientists: why weren’t the great white numbers returning to what they were?

Orca predation is not an unknown occurrence and is often reported in American and Australian waters. However where their case differs from South Africa’s is that their shark populations typically return after a period of a few months. Ours have not. 

The sad, undeniable truth is that we are the real culprits causing this change. The slow and steady decline of their populations in recent decades is due to human activity–not just orca predation. While they contributed to the recent disruption, we cannot control or change their behaviour. Instead we must focus on what we can control.

Directly we threaten them with commercial fishing, trawling and outdated shark nets.

Sharks in general are frequently caught as bycatch in industrial longlines and trawl nets which kill sharks and destroys their habitats. Longline fishing is responsible for at least 20-30 deaths annually, while trawling nets cause an additional 20-40. 

On the other hand, the illegal market for shark products spreads far beyond South Africa and significantly worsens the crisis. In Mediterranean waters great whites are already faced with extinction due to illegal markets and commercial fishing. Whether targeted or caught accidentally, fishermen are often reluctant to release them, given the high value market. In 2025 alone, researchers discovered that at least 40 individuals were killed and sold in North African ports. Beyond being used for display, their meat is sold internationally, processed, and then disguised as fish products

Moreover shark nets originally implemented in the 1950s are still used in many of our bays and are lethal to sharks as well as fish, whales, turtles and dolphins. These devices are designed to kill sharks by effectively strangling them, thereby lowering population numbers and decreasing the likelihood of shark attacks. Every year 20-40 sharks are killed by these nets. We should embrace alternative technologies to protect our swimmers, such as underwater magnetic fields that interfere with the sharks’ hunting senses, or smaller-meshed barriers that reduce the risk of entanglement.

Indirectly we threaten them with overfishing practices that slowly deplete their food sources, such as smaller shark species and fish species. Eventually sharks are forced to migrate since they can no longer find food.

Conservation of these creatures should be encouraged and is needed if we want to avoid a trophic cascade within our ecosystems. Already we are seeing the effects with the rising population of Cape fur seals and broad-nosed sevengill sharks which have notably caused a decline in fish and smaller shark species they consume. Furthermore it threatens the critically endangered African penguins that Cape fur seals prey on. Our ecosystems function through a delicate balance that, when disrupted, creates ripple effects. This reflects an unhealthy ecosystem.

Great whites are among the most protected species on paper, but this should be put into practice. Conservation starts with us. We must act – through education, awareness and change. If we cannot protect a species that has survived mass extinctions, what chance do we have of healing our oceans or our planet? Protecting our seas means protecting humankind. More than 50% of the air we breathe is from our oceans. That is why this matters.

– Mia