Experts believe that the whales carried out an annual sea migration when some of the mammals took a wrong turn.
Two whales were then able to swim out of the river, but one of them was still there.
This is the first time a whale has been seen in a river full of crocodiles in Australia.
Given the approximate length of 16 meters, humpback whale the crocodiles considered it impossible to disturb them.
However, an official on Monday (14/9/2020) said that the risk could increase if the whale washed ashore in shallow water.
What’s going on?
The sight of the animals swimming along the bends of the muddy river – away from the open water – amazed the locals.
“This is something that has never been recorded before – not just in the northern region, but (in) Australia. It’s really unusual,” said Carole Palmer, a marine ecosystem scientist for the regional government.
It is difficult to determine whether more than one whale needs assistance because of “murky brown river water,” he added.
How did the whales get there?
Palmer told Australian Broadcasting Corporation that experts aren’t sure why this whale took a wrong turn off the country’s north coast.
It is estimated that they headed south to Antarctica, but mistakenly entered an estuary that took them farther upstream.
Whales migrate to warmer waters off Australia’s coast during the spring to give birth before returning to Antarctica in search of food.
Is it dangerous there?
Although the river is teeming with saltwater crocodiles, scientists hope there won’t be any fighting.
However, if whales are trapped in shallow waters and stranded on the banks of rivers, “they become easy prey,” Palmer told ABC.
“There’s no way we can lift the humpback whale 12-16 meters from the sandbar and potentially get the crocodiles out.”
What are the authorities doing to help?
To guide it to the sea, a number of boats are forbidden to sail along the river.
It was hoped that the whale would go away on its own, but the whale remained near the deepest part of the river – about 20 kilometers from the sea.
Palmer said authorities were considering several ways to pull it out, such as exploiting the “noise” of boats sailing around the river or recordings of humpback whales.
“This is quite complicated, but everyone is really trying to move it in a positive way,” he said.