CSI: Australia! DNA Exposes Orca Attacks on White Sharks

For years, I’ve witnessed firsthand the impact of killer whales on white sharks in South Africa. Now, new research from Australia has provided undeniable genetic evidence that orcas are preying on white sharks there too. This confirms fears that the behaviour is happening on a global scale.

This latest study used genetic evidence to officially confirm that orcas are preying on white sharks in Australia. It’s a major step in understanding the growing phenomenon of orcas targeting one of the ocean’s most iconic apex predators. And for those of us who have been close to the action between these fierce creatures, and have observed this dynamic in South Africa, it raises even bigger questions.

Apex Showdown: How Orcas Are Impacting White Sharks

I’ll never forget the first time I saw Port and Starboard, the infamous orca duo that turned South Africa’s shark hotspot, Gansbaai, into a ghost town. Their precision in hunting sharks was shocking... tearing out the livers with surgical efficiency and forcing white sharks to flee from what was once our prime hunting grounds for them in Mossel Bay. But nothing could have prepared me for what I documented in 2023: Starboard, successfully hunting a white shark, completely on his own.

It was a historic moment and the first recorded instance of a single orca taking down a white shark without the support of another orca or a pod. Since then, white shark activity in Mossel Bay has dwindled, reduced to sporadic single-shark sightings at best... an exodus at worst.

The first documented case of orcas targeting white sharks was in October 1997, off the coast of California at Farallon Islands. Tourists aboard a whale-watching boat cruising the islands were shocked to witness two orcas take down a white shark and consume its liver. This incident led to the desertion of the white shark populations that normally frequented the islands.

Now, with this new research, it’s clear that orcas hunting white sharks is prevalent among other global populations.

This study, authored by one of the Oceans Research interns I had the privilege of working with, Isabella Reeves, and my good friend Alison Towner , is an exciting and quite unsettling piece of the puzzle, proving that the balance between these ocean giants is shifting. If you’re fascinated by this dynamic as much as I am, read the full study here.

The Predator Power Shift: What’s Next for Sharks?

With white sharks altering their movements and orcas continuing to dominate, we’re witnessing a major shift in the balance of power among ocean predators.

What does this mean for Australia’s shark populations? Could these patterns lead to similar ecosystem changes seen in South Africa?

Read more about my encounter with Port and Starboard in 2023 in The Guardian ’s Age of Extinction series. Watching Starboard so rapidly and easily eviscerating my favourite shark species was utterly devastating and intensely powerful.

Watch the video about the encounter: https://youtu.be/8w3Ao4pgTwM?si=X7_P0kX4tA6kDkuZ

So, who are you white shark killing orcas of Australia? I'm sure research and tourist vessels in those waters are keeping a keen eye on orca activity. Perhaps one day, we’ll be able to identify the individuals with a taste for white shark liver—just as we have with Port and Starboard in South Africa.