Great white shark breaches the surface in pursuit of its prey in False Bay, South Africa. Credit: Chris Fallows, Apex Shark Expeditions.
A new study has found that a marine ecosystem has been disrupted following the disappearance of great white sharks from the area.
Known for their powerful ability to launch out of the water in pursuit of prey, the loss of great white sharks from False Bay in South Africa has scientists and conservationists concerned about the rippling effects on the ecosystem
A new study has uncovered evidence of far-reaching ecosystem consequences following the disappearance of great white sharks (Carcharodon carcharias) from False Bay, South Africa.
The research, conducted by scientists at the University of Miami Rosenstiel School of Marine, Atmospheric and Earth Science, spans over two decades and documents cascading ecological disruptions, underscoring the crucial role apex predators play in maintaining ocean health.
Iconic apex predator
Using a combination of long-term boat-based surveys of shark sightings, citizen science observations on Cape fur seals, and Baited Remote Underwater Video Surveys (BRUVS) of fishes and small sharks, the study provides evidence that the absence of great white sharks has triggered significant shifts in the marine food web.
Lead author Neil Hammerschlag, PhD, said: “The loss of this iconic apex predator has led to an increase in sightings of Cape fur seals and sevengill sharks, which in turn has coincided with a decline in the species that they rely on for food.”
Hammerschlag, who conducted the research while at the Shark Research and Conservation Program at the University of Miami Rosenstiel School, added: “These changes align with long established ecological theories that predict the removal of a top predator, leads to cascading effects on the marine food web.”
Co-author Yakira Herskowitz, a Rosenstiel School former graduate student that analysed underwater video data, said: “The use of underwater video surveys conducted more than a decade apart provided us with a snapshot of the food web both before and after the disappearance of white sharks from False Bay.
“The number of individuals of a given species recorded on the videos not only informs us about their numerical abundance, but also their behaviour, as species under increased predation risk often become more elusive and are thus less likely to be detected on our cameras.”
Profound consequences
The researchers say the study provides empirical evidence that the disappearance of great white sharks creates profound consequences for marine ecosystems.
Hammerschlag said: “Without these apex predators to regulate populations, we are seeing measurable changes that could have long-term effects on ocean health.”
The findings emphasise the importance of global shark conservation efforts, as their loss could have long term consequences on marine ecosystems.
Given the global reliance on healthy oceans for food, recreation, and ecosystem services, protecting large sharks is essential to maintaining biodiversity.
The study is published in Frontiers in Marine Science.
