Sussan Ley says number of humpback whales in Australian waters has grown from 1,500 at height of the commercial whaling industry to estimated 40,000
Humpback whales have been removed from the threatened species list after a significant increase in numbers in the 60 years since they were first protected, but green groups warn populations could decline again as oceans warm.
Global heating is predicted to have a significant impact on krill populations in Antarctica, a major feeding ground for humpback whales.