Whales stranded in crocodile-infested river

A huge black creature has been spotted emerging from the murky rivers of remote northern Australia.

It's a humpback whale, a long way from home.

"It was like a Loch Ness monster kind of thing."

Marine ecologist Jason Fowler discovered three whales in the crocodile-infested rivers of Kakadua National Park on a fishing trip with friends two weeks ago.

"I knew they were humpbacks because I've done a lot of Humpback research in the past. But I could not convince myself I was actually looking at a whale so far up a muddy tropical river that was full of crocodiles. I was completely blown away."

Fowler said the whales like to be in open sea at least 10 feet deep, but they appeared stuck in a "hole" in the river.

He said it was the first known case of whales in the tropical inland habitat.

Parks Australia said in a Facebook post that it appeared some of the whales had since made their way out of the river and just one was left.

It had put an exclusion zone around the area as experts decided whether to intervene.

The post said that ''the last thing we want is a collision between a boat and whale in waters where crocodiles are prevalent and visibility underwater is zero.''

Fowler says he thinks it's unlikely the whales would be attacked by crocodiles due to their size, but the reptiles still pose a threat.

''The whales are so large, it would be a very very courageous crocodile to try and take a bite out of a whale. The big question in my mind is: what happens at night? What happens when they want to rest and sleep and take it easy knowing that they're flanked by these big crocodiles who are waiting for that moment to strike."