SYDNEY - An extremely rare white humpback whale has been spotted off the coast of Sydney in an event onlookers called a once-in-a-lifetime experience.
The albino is believed to be Migaloo, the world's best-known all-white humpback who has built up a loyal following in Australia since first being sighted in 1991.
Migaloo is an Aboriginal word meaning "whitefella".
He was seen off Sydney on Thursday afternoon with Twitter reports of more sightings further up the east coast on Friday.
"What can I say? A once-in-a-lifetime opportunity seeing Migaloo the white whale swim past," said Jonas Liebschner of Whale Watching Sydney who spotted Migaloo near the southern suburb of Cronulla.
"He was travelling in a competition pod of five adults... and a great deal of zigging and zagging."
A competition pod is where several males compete for the attention of a single female.
"There is an exclusion zone of 500 metres (yards) around him which we stuck to but with the nature of a competition pod it's sometimes hard to predict where they will come up next.
"We got extremely lucky and had Migaloo come up just five metres next to our boat - what a sight that was!"
Humpback whales are currently on their annual southern migration from Antarctica to warmer waters in Queensland state to give birth and mate.
Oskar Peterson, who runs the Australian-based White Whale Research Centre, said a study by Southern Cross University in 2003 had shown Migaloo was male. He was now believed to be around 28 to 30 years old and humpbacks can live to 80.
"He is the only white whale in the southern hemisphere that we know of," he told AFP.
"We have seen evidence of another white whale in the Northern Arctic Zone off Norway, but that is it.
"So it is a very rare sight. Some years you see Migaloo but other years he goes missing in action."
In 2011, a baby white whale, believed to be just a few weeks old, was seen off Queensland's Whitsunday Islands, but it has not been spotted since.
"We don't know if it survived," said Peterson. It was not known if the calf was Migaloo's.
He added that Migaloo would gradually make his way as far north as Cooktown in the Australian tropics "singing songs trying to attract a mate" before the return trip to Antarctica later in the year.
Australia's east coast humpback population has been brought back from the brink of extinction following the halting of whaling in the early 1960s.