Public banned from City Beach as expert warns scent of 31-tonne whale carcass could attract sharks for a week

A shark expert has warned the “juices” of a 31-tonne whale carcass would likely remain in the waters around City Beach for at least a week even after the animal has been removed, attracting sharks to the area.

The giant whale washed up Monday morning, luring not just hoards of onlookers to the sand but plenty of giant great white sharks into the shallows as well.

On Tuesday those on the beach stood and watched a 5m great white less than 20m away.

The sight also made for more incredible drone footage but authorities are frustrated about the number of private drones hovering in the area, at times stopping the shark spotting helicopter from being where it needed to be.

Macquarie University Fish Lab head Culum Brown expected sharks would hang around the area for at least a week after the whale is eventually trucked away.

“The juices and the smell from that carcass will be seeping into the sand, leaching through into the sand and it’ll take several tide flows, depending on how high up on the beach it ends up,” he said.

“I assume they’ll tow it away at some point and throw it in a landfill but it’ll take several tides to flush that fully out of the sand.

“Sharks have an exquisite capacity for smell so I imagine they will be still attracted to that location for quite some time yet.”

At this stage, there’s no confirmed timeline for the whale removal.

Mr Brown said he wouldn’t be diving into the waves at City Beach for at least a week after the whale was removed, saying swimmers should opt for other beaches while the scent of the whale lingered.

He also urged authorities to keep a very close eye on the waters for the foreseeable future.

“If I was in charge, I’d probably have a drone up if you’re going to have people in the area, I would have a drone up making sure that they don’t go in the water and that the sharks do eventually swim off, but it may take some time.”

“If you really wanted to, you could get a dredge in there and dredge it away, but that’s a fair bit of effort for something that the tide and time will take care of on its own, you’ve just got to keep the people out of the water.”

While hundreds have come to see the spectacle over the past day and a half, Town of Cambridge mayor Gary Mack instructed people to stay away while heavy machinery is brought in to remove the decomposing humpback whale carcass.

“It’s anticipated the carcass will be removed tomorrow, and it will be ultimately extracted, put on transport, and taken to a landfill site,” he said.

“Because the extraction is happening tomorrow, a big part of the beach will be excluded. People, pedestrians, and so on will be excluded to ensure the safe operations of the contractors who will be doing this work, it’s complex and potentially risky work because the whale weighs tonnes.”

He said that drones capturing footage of the event had interrupted operations and asked the public to cease filming from above.

“What we don’t want is drones to be flying over the area because that is will potentially interfere with helicopters and also the boats that are out there to assist with us,” Mr Mack said.

“It’s very unhelpful for us, it poses a risk to helicopters, some of which are Surf Life Saving assets. It poses a risk to boats out there that are trying to help us. So we prefer people wouldn’t fly drones in this area.”

The beach will not reopen until the carcass is removed and lifeguards are assured the sharks are not around.

But Mr Mack warned eve then, swimmers should stick to swimming between the flags on patrolled beaches.

“That’s where the concentration of life-saving assets are. That’s where people have got a clear vision on the ocean, and that would be the safest place if in doubt,” he said.

“Some people are, you know, quite justifiably frightened of sharks.”

He reminded the public that South City Beach was not patrolled and that swimmers should steer clear of it for the time being.

Authorities on Tuesday were attempting to tag the sharks lured to shore by the decomposing whale carcass after several were spotted circling the area.

Three shark-fishing drum lines were put in the water from a boat just off City Beach, where the whale remains on the shoreline.

One 3.7 metre white shark was tagged and released off Floreat Groyne on Tuesday.

The public is being patrolled by officers from the Department of Biodiversity, Conservation and Attractions (DBCA) who have established a small fence to keep people back from the whale.

The Department of Primary Industries and Regional Development confirmed on Tuesday it was seizing the opportunity to do some tagging while the sharks are lingering close to the beach.

None of the sharks spotted swirling the carcass on Monday were tagged. Some were reportedly as big as 5m in length, and just 10m from the beach.

It comes as authorities come to terms with the practicalities of removing the whale carcass which washed ashore on Monday about 7.30am.

Hundreds turned out for a glimpse of the 13m humpback whale on Monday after its reported stranding triggered a shark frenzy, and there are crowds of people back at the beach this morning.

Several sharks, including great whites, swam just metres from the shore as members of the public stood alongside the whale - estimated to weigh about 31 tonnes - with some even deciding to reach out and touch it.

No sharks circling the carcass were tagged, however the public, Westpac helicopter, and Surf LIfe Saving WA, made several reports throughout the day of their sightings.

Great white sharks in varying sizes between three and five metres were reported swimming 10 and 15m from the shore near the carcass throughout the morning and afternoon.

A tagged white shark pinged receivers just north of the carcass at City Beach later in the day, once at 4.34pm, another time at 11.27pm and again at 11.32pm.

A white shark also pinged the Floreat receiver five times between 8.06pm and 10.08pm.

The removal of the whale is in the hands of the Town of Cambridge, but it’s not yet known when the animal will be removed or where it will be taken.

“This is a complex and potentially hazardous operation involving a very large carcass, heavy machinery and specialist personnel, and we need to ensure we can do this safely before work begins,” Cambridge council mayor Gary Mack said.

“Our focus is on removing the carcass intact as much as possible, at the earliest safe opportunity.”

He said public safety would determine when City Beach reopens, but it could be several days.

“Wild carcasses attract sharks, and people nor their pets should actually go into the water at all while the beach is closed and should look after their personal safety,” Mr Mack said.