In a rare occurrence off Western Australia's south coast, the sounds of a female orca have been captured on tape.
In the short clip, shot about 50 kilometres offshore from the popular tourist town of Bremer Bay, the apex predator can be seen looking at the underwater camera while she emits a clear song.
Naturaliste Charters marine biologist Pia Markovic regularly collects data on the different pods that frequent Bremer Canyon and says this particular orca is well known to tourist operators and researchers.
"The orca actually goes by many different names," she told the ABC's Peter Barr.
"When we recorded that sound, she was right next to the side of our vessel, calm and confident.
"She was swimming around with her belly up at first and then rolled over and made a heap of noise at the surface that we could hear from on the boat.
"Then when we put the GoPro down she turned around and made that sound underwater."
First time for researchers
Ms Markovic said this was the first time she had heard an orca's song in such high quality.
"I've heard her once before on the surface and it almost sounded like she was trying to mimic the boat," she said.
"She was kind of blowing up blowing us raspberries at the surface.
"But we've just never had that audio before.
According to Ms Markovic, orcas around the world will make different sounds and researchers are still trying to determine what they mean.
"Some will be really chatty, especially fish-eating orca — they've been found to be quite chatty because fish have poor hearing, so the orca can chat as much as they like," she said.
"Mammal eating orca are a little bit quieter on a lower frequency.
"The Australian killer whales, or the Bremer Bay killer whales, they are a bit of a mix of both."
Friend or foe?
Ms Markovic said Split Tip seemed to be sharing a friendly message.
"We know that she didn't mind being there," she said.
"She didn't show us any aggression or aggressive behaviour.
"Every time I put the GoPro in my bag, I think, 'What's it going to capture today?'"
"And you just never know, because every day is a new day out there."
The Bremer Canyon is gaining international recognition as a marine hotspot, attracting scientists and tourists from around the world wanting to witness whales, sharks, giant squid, sea lions and birds in their natural habitat.
