Although bull sharks are not seen every day in the Brisbane River, they are well known to live there.
Local Quentin Arnstrong was on his usual morning river walk near Newstead in Brisbane’s inner north when a friend told him about the shark sighting.
“I ran out there and took some pictures, but the strangest thing was no one stopped and looked,” he said.
“I think it’s because it blended into the rock…” [which] It makes you think about how quickly they can sneak up on you in murky water,” he said.
Mr. Arnstrong, an avid scuba diver, said he had never seen a bull shark up close. (Provided by: Quentin Arnstrong)
Mr Arnstrong, an avid scuba enthusiast, said he often dived with gentler species of sharks such as gray nurse sharks, leopard sharks and wobbegong sharks around Byron Bay in New South Wales.
It was the first time he had seen a bull shark up close.
“There’s a reason no one swims in the Brisbane River. I think everyone local knows there are bull sharks out there.”
Mr. Arnstrong said:
“There didn’t seem to be any injuries, but there was some blood underneath.
“I think it chased something up the river, ran ashore on the beach, couldn’t get back, and suffocated in the air.”
Is it real or not?
When Arnstrong uploaded the video to social media, it quickly racked up more than 700,000 views, but it also sparked debate over whether the post was genuine.
Some users claimed the video was AI technology, with some pointing to the iconic Brisbane City Cat as a reason to believe the video was fake.
“People were zooming in on the ferry and saying, ‘ferries don’t work like that,'” Arnstrong said.
Speculation about the AI was mixed, with some skeptical viewers pointing out the iconic CityCat and insect shadows. (Provided by: Quentin Arnstrong)
“Others claimed it was real because they zoomed in on the shark and saw a shadow. That’s the level of detail people look for to verify if something is real.”
“It’s kind of scary that you can’t even take videos or photos of wild animals without someone debating whether it’s real or not,” Arnstrong said.
People are “hesitant to believe”
Tama Lieber, a professor of internet studies at Curtin University, echoed Mr Arnstrong’s sentiments, saying sharks were one of the most popular elements inserted into videos where they weren’t supposed to be.
“Even before generative AI, there were a lot of fake videos of sharks in floodwaters.”
he said.
“That’s why people are hesitant to trust sharks in unexpected situations. This is one of those examples.”
Professor Lieber said there are several indicators to identify whether a video is fake.
- Context — “What if there was a shark in the river?”
- Verification by a third party or certifier – “Can I trust the person who uploaded the video?”
- Image manipulation — “The background is blurry, details don’t look right”
Tama Lieber says identifying AI videos will continue to become more difficult. (Supplied)
“If the person who took the video had multiple angles of the shark, that would be enough to think it was real, but that wouldn’t last long,” he says.
Experts have expressed concern that AI tools will eventually start generating multiple angles of a product, making it difficult for technology to verify content.
“The amount of fakery that was produced within hours of the Bondi shooting alone is a high-end example of how bad it can get.”
Professor Lieber said:
“The arbiters we once trusted to keep things in check can turn anyone from politicians to criminals wrong without reliable verification.”
“It’s a bull shark.”
Dr Adrian Gutteridge is a shark biologist with the Marine Stewardship Council.
He identified the animal as a bull shark and said the species is typically washed ashore when it is sick or dying.
“It is most likely a bull shark. The shape and lack of fin markings suggest it is a bull shark, which is well known to inhabit the Brisbane River,” he said.
Adrian Gutteridge said the presence of bull sharks in the Brisbane River was “well known”. (ABC News: Curtis Rodda)
“I grew up there [Brisbane] And we all know about “brown snakes”… That’s what bull sharks are, one of the few shark species that travels between oceans and river systems. ”
Pregnant female bull sharks typically swim upstream into freshwater and give birth, with fewer natural predators and more food sources available.
As the sharks grow, they migrate down the river towards the estuary and Moreton Bay.
Bull sharks rely on a variety of senses when hunting, including sight, smell, and electrical reception around their noses. Therefore, they live in murky water.
“It’s important to avoid swimming in murky water and avoid swimming after it rains, but in this case I would probably avoid swimming in rivers.” [only] It’s the shark’s fault, but it’s also the water quality’s fault,” Dr Gutteridge said.
Also regarding Mr Arnstrong’s video, Dr Gutteridge said if a recreational fisherman caught that particular shark, it would likely have to be released due to size and number restrictions in Queensland.
