Tom Cannon knew he was witnessing a rare natural phenomenon when he captured footage of whale sharks feeding on bait balls on Western Australia's Ningaloo Reef.
But the underwater ocean photographer never imagined the sheer scale of how that footage would travel across the world, and that it would be used by scientists to gain insight into the complex feeding behaviour of the largest fish species on earth.
"It was probably the most exciting experience I've ever had in my life," Mr Cannon recalls, of the moment he captured the footage in March 2020.
"I realised at the time, as soon as I got in, that it was a very rare thing and I needed to try and keep my cool and document this," he said.
Mr Cannon, who has lived in Coral Bay for seven years, said the bait ball was causing chaos underwater as sharks, trevally, mackerel tuna and wedge-tailed shearwaters all made feeding attempts on the bait fish — before being joined by four whale sharks.
"They were sort of lining up from a distance and they were using the agility and the speed of the pelagic fish and the sharks that were kind of balling up the fish," he said.
"They were coming in and taking big run ups and just opening their mouths and going straight through the middle of the bait ball.
"It's one of those things that you hope will happen again in your lifetime, but you're quite sure it's not going to."
He filmed the action for 45 minutes — maxing out memory cards, draining the batteries on his cameras.
The experience left him with an excitement that didn't die down for days and footage that would later "explode" across social media platforms.
But Mr Cannon said it was science that took that footage to the next level.
Earlier this year, Hawaiian Institute of Marine Biology marine scientist Emily Lester published a paper about whale sharks feeding on bait balls based on Mr Cannon's footage on the Ningaloo Reef.
"Normally, we think of whale sharks as these slow moving, filter feeding animals that … feed on plankton," Dr Lester said.
"In this video, they're quite animated, they're moving quite quickly and they're feeding on bait fish."
She said the footage provided compelling insight into how animals might be working together to get the "biggest mouthfuls".
"The tuna and the sharks tend to look like they're herding the bait ball from below and getting it into this nice densely packed formation," she said.
"When the whale sharks swim through this bait, these bait fish scatter."
Bait balls were an anti-predator defence that made the bait fish hard to isolate and capture, she said.
"When a big whale shark swims through it and isolates little groups, these other predators can swoop in, in the case of the birds, or swim in, in the case of the sharks and get these isolated individuals," Dr Lester said.
"It's absolutely remarkable and it's really cool to get an insight into the dynamics that might be at play here — like how these multiple predators are all capitalising on this absolute feast."
