White Wings was catastrophe's child. Now a 40-tonne mother, she is guiding her newborn calf down the East Coast of Australia on a journey of survival which will be observed by close to one million people around the world.

A 13-metre adult, White Wings was born at a time when Australia's east coast humpbacks faced extinction, her struggle to stay alive and breed has mirrored one of the great comebacks of a species hunted for financial gain.

White Wings and her calf, born six weeks ago in the tropical waters north of the Whitsundays, are at the beginning of a three-month, 6000-kilometre swim that will end in November when they reach summer feeding grounds in the Antarctic.

They are south of Hervey Bay - where they were observed by old friends, the humpback researchers Wally and Trish Franklin, who named White Wings - and are moving at about 3kmh, driven by instincts we have yet to fathom.

The reunion was a moment of great emotion for Trish Franklin, who photographed White Wings in Hervey Bay with three calves in 1998, 2000 and 2002. "It was an absolute joy," said Ms Franklin, 64, who in 14 years has compiled the world's greatest individual catalogue of humpbacks, 3000 of which she can identify from photographs, 700 of which she has named and about 200 of which she can recognise on sight.

All down the coast of Queensland, NSW and Victoria, small teams of dedicated researchers and hundreds of thousands of whale lovers, in boats and on headlands, will be on the lookout. Watching whales is reaping greater rewards than killing them - $276 million in Australia last year, $1 billion globally.

White Wings was one of a small number of females born soon after the slaughter was stopped in Australian waters in 1963, with no more than 250 humpbacks still alive. The population was so reduced most believed they were beyond recovery.From that nucleus of breeding stock has come a steady stream of new females, sufficient to push the population to an estimated 5500, including about 500 calves born this season.

In a 16-day period off Byron Bay in June and July, Dan Burns, 28, from the Whale Research Centre at Southern Cross University in Lismore, counted 855 humpbacks going north, 300 more than the same survey in 2002. With other data, researchers believe the numbers are growing by about 9 per cent a year.

"If they're left alone, there's every chance they'll regain pre-hunting populations, but it's going to take time and care," Mr Burns said. Most estimates put that population at about 35,000.