When up to 150 killer whales and their calves surrounded their boat, the crew knew they were looking at a special and, until now, unknown place off WA's south coast.
About 70km from Bremer Bay, the WA research team saw what is believed to be the biggest seasonal offshore populations of killer whales - rarely seen in Australian waters - in the Southern Hemisphere.
The orcas congregate for about six weeks a year at a 500sqm "hotspot", where and when the seabed is thought to give off a plume of nutrients that attracts a teeming mass of diverse marine life, including great white sharks and giant squids.
"There is a lot of activity out there, a lot of different species that are obviously feeding," Esperance filmmaker David Riggs said.
"It ranges from being very violent behaviour to very playful behaviour.
"They are very focused, then all of a sudden it just changes and it's the most amazing interaction."
Riggs has watched the spectacle yearly for the past eight years as part of his research and this year he took a team of marine scientists and experts to show them and to make a documentary.
"Everyone was sceptical that what I'd been observing was of the magnitude I'd been explaining," he said.
"Their mouths dropped open when they saw it was."
The discovery started 10 years ago when a tagged 3m great white shark mysteriously disappeared close to the "hotspot", which is part of an oil and gas tenement.
The shark, named Alpha, was tagged four months before the device washed up on a beach near Bremer Bay.
A passerby found and returned the tag so the data could be downloaded.
The tag data revealed Alpha's incredible journey and demise. She swam 4000km along the WA coast from Bremer Bay to Exmouth and back.
But Alpha ran into trouble near the "hotspot".
She dived quickly down the edge of the continental shelf to a depth of 580m where the external tag had a temperature reading of 8C. Suddenly, still at 580m deep, the tag's temperature shot up to 26C.
It stayed at that temperature, at varying depths, for about a week until it was released and floated to the surface.
The most likely scenario was that, after being chased to the ocean floor, the shark and its tag were eaten by another creature.
When Riggs heard the story in January 2004, he was intrigued. He wondered what kind of creature could have caught and eaten a big great white shark, the ocean's apex predator, and he set about finding out.
This year, using underwater cameras and aerial photography, Riggs and his team tried to capture marine life and activity at the hotspot.
"It's quite a unique spot," he said. "There's definitely an upwelling from the canyon mouth, which is adjacent to it.
"I suspect there's some sort of nutrition that's leaking from the sea floor that is propelled vertically through the water column as the cold currents on the sea floor strengthen over summer."
The team saw killer whales, sharks, birds and other creatures devouring pieces of white meat.
An aerial photograph revealed a killer whale pulling along what Museum Victoria squid expert Mark Norman described as either the biggest giant squid on record or something he did not know.
Dr Norman said it was not physiologically possible for a giant squid to have attacked the great white shark Alpha.
Riggs said one of the killer whales, which they named A380 after the world's biggest passenger plane, was about 10m long and raised the possibility that a killer whale ate Alpha.
The third possible predator is another great white shark.
The species is known to be cannibalistic.
"We still haven't conclusively identified what it was that ate it and that's the reason for more research next year. It's fascinating," Riggs said.The Search for the Ocean's Super Predator airs tomorrow at 7.30pm on ABC1.