For the first time in history orcas have been filmed hunting and killing an elusive whale species in Australian waters.
On Easter Saturday whale watchers off the coast of Western Australia's Bremer Bay were treated to the rare sight of both the Cuvier's beaked whale and its demise.
Naturaliste Charters deckhand Billy Thom said the vessel had been observing a pod of orcas when they took off at great speed to the south.
"They started porpoising, which is an efficient way of moving through the water at a fast speed," he said.
The vessel followed until the pod began to slow again.
"I saw a swell of birds about 300 metres in front of the boat," Mr Thom said.
"There were about 20 to 30 birds circling over another pod, and we realised it was following an injured beaked whale.
"At that point I started looking ahead of us and I could actually see another couple of pods coming in."
Mr Thom said blood was pooling in the water as almost 50 killer whales encircled the injured beaked whale.
Bremer Bay a 'biological hotspot'
Cuvier's beaked whale are considered elusive due to the amount of time they spend underwater.
They're able to reach depths of up to 3km and are known to be able to hold their breath for more than two hours.
While orcas can only reach depths of 100m, pods work in unison to keep their prey near the surface while simultaneously preventing it from being able to breathe.
Naturaliste Charters Marine Biologist Bianca Uyen said orca predation had only been witnessed a handful of times in the area.
"This year we've seen three confirmed predations on beaked whales," Ms Uyen said.
"But this particular one was the very first on the Cuvier's beaked whale that we've ever seen.
"We also haven't seen as many orcas involved in a single predation either."
In recent years Bremer Bay has gained notoriety globally as a biological hotspot.
"This footage shows how important this area is in terms of general biodiversity," she said.
"Beaked whales are one of the least studied mammals in the world because they're rarely seen on the surface.
"Through instances like this we're able to learn more about them, not just the killer whales."
