Marine biologist warns of shark attraction after whale carcass removed from Clarence River

In short:

A marine biologist says the smell of a whale carcass recently removed from the Clarence River will attract sharks.

The carcass has been taken out to sea a day after it was spotted on a sandbar near Iluka on the Mid North Coast.

What's next?

The marine biologist says people should wait about a week before entering the water.

A marine biologist says sharks are likely to be attracted to a New South Wales sandbar where a dead whale was left for more than a day.

Crown Lands worked to remove the carcass from the Clarence River west of Iluka on the Mid North Coast. It was taken out to sea on Sunday afternoon.

Volunteer whale rescue organisation ORRCA was notified about the whale at 1:30pm on Saturday.

An ORRCA spokesperson said there were concerns that the juvenile humpback may have been stranded, but volunteers found it deceased.

The Department of Primary Industries and Regional Development released a warning on Shark Smart social media accounts stating that increased shark activity had been reported.

Macquarie University marine biologist Culum Brown said the smell of the carcass would linger.

"If it's been there for that long it will already be leaching all sorts of good smells into the river and the surrounds, and the sharks will certainly be able to smell that for a long way," he said.

"I would be making sure that nobody was swimming in the river or the adjacent beaches.

"My advice would be to stay out of the water for the next week or so, which is not what people want to hear on the long weekend."

Dr Brown said he was surprised that the whale had travelled 11 kilometres up the river.

"That doesn't happen every day," he said.

"To get that far up a river is very strange, it makes me wonder if perhaps a mother and calf did come into the mouth and perhaps the mother turned away and the baby kept going."

Footage of the deceased whale was recorded by Brooms Head photographer Amiria Takarangi.

She said filming the animal it was unsettling.

"It felt wrong, honestly. But I reminded myself why I do this — to show compassion, to understand, and to share whatever knowledge I can gather," Ms Takarangi said.