Yes, There Are Bull Sharks in the Brisbane River — and They Can Swim All the Way to Ipswich!
Look across the Brisbane River today and it can seem completely peaceful.
CityCats glide past. Rowers train. Fishermen cast their lines.
But beneath that muddy water lives a powerful predator that was part of this river ecosystem long before Brisbane became a European settlement.
Meet the bull shark - Carcharhinus leucas.
And yes… they’re still here.
HOW FAR UPSTREAM DO THEY GO?
Much farther than many people realise.
Queensland Museum ichthyologist Jeff Johnson has reported bull sharks regularly being seen around Colleges Crossing, near Ipswich.
Researchers have also recorded bull sharks travelling roughly 90 kilometres upstream, into areas west of Ipswich.
And there's an incredible piece of local history:
Before the Mount Crosby Weir was built, bull sharks were reportedly found as far upstream as Lowood.
How can a shark travel so far inland?
Because bull sharks are exceptionally well adapted to freshwater. Unlike most shark species, they can spend extended periods in rivers and freshwater environments.
THE BRISBANE RIVER HAS A DARK SHARK HISTORY
The Brisbane River has witnessed shark encounters for almost two centuries.
A Queensland Government review records the first recorded unprovoked shark bite in Queensland in 1847 - in the Brisbane River.
For the Brisbane River specifically, the review records 19 unprovoked shark bites, including four fatalities.
The recorded fatalities occurred in 1862, 1880, 1901 and 1904.
In many historical cases, the shark species was never positively identified. However, the Queensland Government considers the bull shark highly likely to have been responsible because it is the large shark species consistently associated with the river, particularly its upstream reaches.
One of the most tragic incidents occurred in 1880.
Twelve-year-old Alexander Drury was swimming at Deep Rock, opposite Kangaroo Point, when a large shark seized him by both legs.
His friends desperately tried to pull him from the water.
Drury suffered catastrophic injuries and later died.
Contemporary newspaper reports documented the horrific encounter.
Further fatal attacks were recorded in 1901 and 1904, including the deaths of John Thompson, who was attacked while bathing near the Brisbane Rowing Club, and George Grant, who was killed after entering the river to retrieve his hat.
WHAT ABOUT THE BIGGEST BRISBANE RIVER SHARK?
In the 2007 Brisbane River Classic, fisherman Terry Hessey caught an extraordinary 2.9-metre bull shark.
The tournament scales could only measure up to 200 kilograms, meaning its actual weight wasn't recorded.
It was estimated at approximately 250–300 kilograms.
It's been described as the largest shark believed to have been caught in the Brisbane River - although that estimated weight should be treated cautiously because it was never actually measured.
Still… 2.9 metres is one enormous river shark.
WHAT DO BRISBANE RIVER BULL SHARKS EAT?
Bull sharks are opportunistic predators.
Queensland Museum research indicates that Brisbane River bull sharks feed on:
Mullet Bony bream Gar Fork-tailed catfish Eels
Their diet can also include crustaceans and other aquatic animals.
And humans?
We're not their normal prey.
Their everyday diet is primarily fish and other aquatic animals. But bull sharks are powerful predators, and attacks on people have occurred.
THE BRISBANE RIVER IS ALSO A SHARK NURSERY
Perhaps the most fascinating part is that the Brisbane River isn't simply somewhere bull sharks pass through.
It's part of their life cycle.
Female bull sharks give birth to live young, and juvenile sharks can spend their early years in rivers and estuaries.
Research discussed by Queensland Museum's Jeff Johnson estimated that more than 98% of bull sharks in the Brisbane River were juveniles, generally between one and six years old.
That research also estimated the river population at around 1,000–3,000 sharks.
Importantly, that's a research estimate - not a current population count.
So why do so many young sharks head upstream?
One possible advantage is reduced predation. Smaller bull sharks can move into upstream areas where there may be fewer large sharks capable of preying on them.
And here's another incredible fact…
Bull sharks have been observed moving through extremely shallow water around Colleges Crossing.
They've even been seen launching themselves clear of the water in the Brisbane River!
THEY WERE HERE LONG BEFORE BRISBANE
European settlement at Brisbane began in 1825.
Bull sharks weren't introduced by settlers.
They're a native part of Australia's river and estuarine ecosystems, meaning they were part of this environment long before Brisbane became the city we know today.
We can't put an exact number of thousands of years on their presence in the Brisbane River.
But we can say with confidence that bull sharks predate European Brisbane by a very long time.
So next time you're standing beside the Brisbane River…
Look down.
Beneath the CityCats, bridges and reflections of Brisbane's skyline…
bull sharks are still swimming.
And they've been part of this river's story for far longer than we have.
Sources: - Queensland Museum & Wikipedia
Photo: João D'Andretta — iNaturalist, CC BY 4.0
