Shark disappearance warns of deeper biodiversity crisis

THIS week, the world observed International Day for Biological Diversity and South Africa is faced with a harsh reminder of what's at stake with the dramatic disappearance of the great white shark from its once-thriving hunting grounds in False Bay.

- STAFF REPORTER

The UN marked May 22 as a day to reflect on the critical importance of biodiversity as a yardstick for humanity and the planet. Few symbols are as powerful or as endangered as the great white shark, and thanks to break-through research, it's now possible to put a monetary value on the true cost of biodiversity loss such as this.

Once a common sight in False Bay, great white sharks have all but disappeared over the past two decades. Scientists point to unsustainable fishing and commercial longlining, entanglement in protective nets laid out by the Natal Sharks Board, and more recently, predation by orcas as the reason Great Whites have vanished from our coast. Their absence has triggered a domino effect across the marine ecosystem.

A 20-year study by scientists from the University of Miami has uncovered real-world evidence of a food chain collapse. "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 seen a decline in the species they feed on. This confirms the longstanding ecological theory-top predator loss leads to cascading impacts," said lead researcher, Dr Neil Hammerschlag.