Rare White Humpback Calf Spotted Off Australian Coast

A rare humpback whale calf, thought to be one of only a dozen in the Southern Hemisphere, has been spotted off the coast of NSW and Queensland.

Drone footage captured the mostly white calf swimming alongside its mother off the coast of Cabarita Beach on Friday. Excited onlookers then saw the same calf about 100 kilometres north at Minjerribah on Stradbroke Island the following day.

CSIRO scientist Dr Eva Plaganyi, who was among the crowd, said it took her a minute to work out what it was.

"We saw that this calf was almost all white, so looking almost like a small iceberg floating by against the dark of the female whale," she said.

It is thought that this is a leucistic whale, which still have some pigment and normal dark eyes, unlike albino whales that are completely white and have pink or reddish eyes.

"In order to manifest or show this colouration, it is quite a rare genetic mutation … so it is possible Migaloo fathered this particular calf or there could be another reason for this genetic mutation," Dr Plaganyi said.

"It can be an indicator of something happening in this environment, or it can be natural if you get the right combination of parents."

Migaloo, an all-white humpback whale, shot to fame after he was spotted in Byron Bay in 1991.

Since then, he has been documented several times during his annual migration with thousands of other humpback whales on their journey from Antarctic waters to warmer waters off the coast of Queensland.

But experts say it will not be known if this is a leucistic whale, or whether Migaloo is the father, until the animal is genetically tested.

"This one definitely makes people look twice, it is very white on top so you'd be forgiven to think the whole thing is white until you see the darker bits," Dr Vanessa Pirotta, a whale scientist at Macquarie University said.

Citizen scientists encouraged to log spottings

The calf and its mother will continue to travel further north to warmer waters off the coast of Hervey Bay in Queensland, where it is hoped more people will be able to document it.

"They are so highly visible that we can draw on citizen science to help us understand and answer questions about the whale," Dr Plaganyi said.

"A distinctive whale like this means all along the coast people can spot the whale and log those observations."

Dr Pirotta said scientists rely on whale enthusiasts and their observations to document the movement of whales, which make huge geographical movements.

"The non-scientists helping out is really wonderful because they can spot things that we don't see, and through social media, we can document whale movements," Dr Pirotta said.

The peak whale-watching season in Queensland is between May and October, and there are strict rules in place for boats, jet skis and drone operators.

Guidelines say swimmers should stay 100 metres from whales and vessels 300 metres, while the buffer zone for drones is 100 metres in any direction.

However, if the whale is predominantly white, then those restrictions tighten even further, and boats and jet skis need to stay 500 metres from the animal and aircraft need to stay 610 metres above them.

"The usual strict whale watching guidelines are even stricter when it comes to special animals, like I think this new calf will be," Dr Plaganyi said.

"Is it a good thing being all white? We don't know, maybe it makes them more vulnerable to predators, but we know it means people will be able to spot this whale forever, which means any animal that is more than 90 per cent white is kept safe and at a distance."