SYDNEY: Australia's humpback populations have recovered so well from years of devastating whaling that they could be delisted as a threatened species in a conservation success story scientists Tuesday hailed as "a symbol of hope".

Humpback whales were commercially harvested around the Australian coast between 1912 and 1972, with tens of thousands of the animals killed, decimating the species.

But their recovery has been remarkable, spawning a thriving whale watching industry.

A new paper, "Embracing conservation success of recovering humpback whale populations", said Australian numbers were increasing at nine percent a year off the country's west coast and 10 percent for the east coast.

As of 2012, they had grown to more than 63 percent (east coast) and 90 percent (west coast) of those recorded before the whaling era.

Australia's Murdoch University's Cetacean Research Unit, which contributed to the paper published in the journal "Marine Policy", said it was a rare success story.

"For the first time in over a generation, the iconic humpback whales of Australia have become a symbol of both hope and optimism for marine conservation," it said.

"Optimism in conservation biology is essential to encourage politicians, policy makers and the public to solve conservation problems."

The paper, which also involved scientists from Oregon and North Carolina in the United States, said the animals were now no longer at risk of extinction and proposed they be delisted as a threatened species under Australian law, where they are listed as vulnerable.

The once over-exploited whale has already had its conservation status downgraded in other regions including the North Pacific population off British Columbia, Canada.

Marine scientist Michelle Bejder, who led the review, said removing humpbacks from the threatened list would be allow conservation funding to be redirected towards other species more at risk.

"Hopefully other animal species may be afforded a similar chance of recovery success to that of the humpback whales," she said.

"Blue whale populations have been depleted greatly and remain endangered, while very little scientific data is available on Australian snubfin dolphins and Australian humpback dolphins."

Bejder said management efforts must now balance the need to maintain humpback whale recovery within a marine environment experiencing increased coastal development and rapid growth in industrial and exploration activities.

"Increased interactions with maritime users are likely to occur," Bejder said, including acoustic disturbance from noise, collisions with vessels, entanglements in fishing gear, and more interactions with the booming whale watching industry.

"Adaptive management actions and new approaches to gain public support will be vital to maintain the growth and recovery of Australian humpback whales and prevent future population declines," she added.