Researchers seeking further protection for Oceania humpback whales are welcoming a new "endangered" classification for the sub-population, which twice a year migrates past New Zealand.
However, the International Union for Conservation of Nature and Natural Resources listings downgraded the worldwide status of humpback whales from "threatened" to "least concerned", which meant they were at low risk of extinction, South Pacific Whale Research Consortium co-ordinator Simon Childerhouse, a marine mammal biologist of Dunedin, said.
"Ongoing work . . . has demonstrated that while whales in some areas are showing good signs of recovery from whaling, others remain at extremely low levels and still require protection."
Despite the improvement in overall numbers, sub-populations in the Arabian Sea and Oceania were still struggling.
"We welcome the listing of Oceania humpbacks as endangered."
Oceania humpbacks, decimated by commercial whaling, were found around eastern Australia and in the South Pacific, with 300 to 400 passing through Cook Strait every year on their way from the Antarctic to the tropics to mate and calve.
"There has been a lack of recovery of humpbacks in places such as Fiji, Norfolk Island and New Caledonia, with only a very slow recovery in New Zealand."
Numbers had not changed in the past 10 to 15 years, but the research was now available highlighting the population was at much lower levels than thought, Dr Childerhouse said.
It was estimated humpbacks in Oceania were less than 20% of the numbers 60 years ago.
"There is no room for complacency here."
They were under threat from climate change impacting on their food source, getting entangled in fishing gear and from the Japanese, who planned to kill 50 humpback whales in waters south of New Zealand and Australia for scientific research.
The new listing made a stronger case for fighting the Japanese plans, he said.
