A shark expert has warned the “juices” of a 31-tonne whale carcass will remain in the waters around South City Beach for at least a week even after the animal has been removed, meaning sharks will be drawn to the area for a prolonged period of time.

The giant whale that washed up Monday morning lured a number of great white sharks into the shallows on Tuesday as hoards of onlookers watched on from the beach. A five metre great white was less than 20m away from the shoreline, while two other white sharks were caught and tagged at nearby Floreat Beach — including one measuring nearly 4m.

As the Town of Cambridge prepares to try to remove the whale remains on Wednesday morning, Macquarie University Fish Lab head Culum Brown said sharks were likely to hang around the area for at least a week.

“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 be attracted to that location for quite some time yet.”

Mr Brown said 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.

“If I was in charge, I’d probably have a drone up if you’re going to have people in the area,” he said. “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.”

UWA Oceans Institute adjunct research fellow Ben D’Antonio said the whale carcass was an attractive meal for sharks.

“It’s basically a pot of gold for a shark, this kind of mass of food that’s incredibly rich in lipids,” he said.

“For these animals (sharks), their eyes pop out of their heads when they go, ‘wow, so much food, I’m going to sit here and chew it all day’.”

“For a shark, the ocean is vast and it can be really difficult to find food so when there is a whale that’s unfortunately passed away, they float at the surface and they create a buffet for the sharks around them.”

Drum lines deliberately set nearby managed to catch two white sharks on Tuesday in the surrounding waters, measuring 3.1 metres and 3.7 metres.

Fisheries Minister Jackie Jarvis said officials were trying to make the most of the situation.

“We’ll target and tag as many sharks as we can, it’s important to remember when we tag sharks this isn’t just a tag on the dorsal fin,” he said.

“The shark is caught, it is actually pulled up alongside the boat, it is actually turned over, an internal tag is actually surgically inserted, so each shark actually has sort of minor surgery on it.

“It is a mammoth task, they do a fantastic job and the idea of these opportunistic drum lines is to tag as many sharks as possible.”

Dr D’Antonio said elevated shark activity was to be expected, and people should be cautious not to interact with them.

“They are feeding and they’re a wild animal, so it’s not wise to interact with animals when they’re feeding, just like when you might have a dog gnawing on a bone, you wouldn’t tell a child to go pet the dog because the dog’s behaviour is unpredictable,” he said.

“It’s the same with a shark, they are wild animals and at any time it’s not wise to interact with wild animals because their behaviour is unpredictable, but certainly when there is food around.”

All beaches in the local government area remained closed on Tuesday evening, with an exclusion zone spanning along South City Beach for an excavator and workers to begin the massive task of removing the whale on Wednesday morning.

But a Town of Cambridge spokesperson said existing rules had already been broken.

“Unfortunately, some people have breached the existing barriers, these controls are in place for public and worker safety, people must not enter the exclusion zone, and anyone who disregards the barriers or lawful directions may be issued with an infringement,” they said.

Cambridge mayor Gary Mack 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.”

Ms Jarvis said the beaches would not open for the foreseeable future.

“As long as there’s shark activity, the beach will remain closed,” she said. “There’s an abundance of caution and that’s normal practice, regardless of whether there’s a whale carcass or not.

“If there’s significant shark activity, if there’s shark spotted, local government work closely with DPIRD to to make sure the beaches remain closed.”

Some onlookers who came to witness the sharks so close to shore appeared unfazed by the potential risk.

“I think we’ll be in pretty soon,” Analeigh Brown said. “I don’t think we’d be too bothered by it, but we don’t go out very far.

“I can see how most people will probably (wait), there’s a huge fear of sharks all the time.”

But others were more cautious, such as Chris Payne who has been more worried of sharks since swimmer Greg O’Neill was taken at Sorrento beach less than two weeks ago.

“Absolutely, especially with that gentleman taken from Sorrento, that hit home a bit more than the other ones, as it was 15 meters out, that’s where everyone swims,” he said.

“That’s something to think about for sure.”