OSLO (Reuters) - Some large whale species such as the humpback, minke and southern right whale are recovering from a threat of extinction, helped by curbs on hunts since the 1980s, the world's largest conservation network said on Tuesday.
A review of cetaceans -- about 80 types of whales, dolphins and porpoises -- showed almost a quarter were in danger, mostly small species. Entanglement in fishing gear was the main threat, the International Union for Conservation of Nature (IUCN) said.
"For the large whales the picture looks guardedly optimistic," Randall Reeves, chair of the cetacean specialist group of the IUCN, told Reuters of the assessment of marine mammals for the IUCN's "Red List" of endangered species.
"The large whales, the commercially important ones, have for the most part responded well under protection," he said. The IUCN groups governments, scientists and conservationists.
The world imposed a moratorium on all hunts in 1986 after many species were driven towards extinction by decades of exploitation for meat, oil and whalebone. Japan, Norway and Iceland still hunt minke whales, arguing they are plentiful.
The humpback whale, which grows up to 50 feet and is found in all the world's oceans, was moved to "least concern" from "vulnerable" in the new Red List.
The southern right whale, found in the southern hemisphere, and the common minke whale, living in the North Pacific and North Atlantic, were shifted down to the "least concern" category from the "lower risk" grouping.
A related species, the Antarctic minke whale which is caught by Japan, was moved to a category of "data deficient", meaning that too little is known to judge how many there are.
Norway expressed hopes that the report would help Oslo's argument that there are at least 100,000 minke whales in the north Atlantic and that the International Whaling Commission (IWC) should relax the blanket ban on whaling.
"We would hope that some of the decisions might be reconsidered," Halvard Johansen, deputy director general at the Norwegian Fisheries Ministry, told Reuters of the IWC. "We will continue hunting minke whales."
Japan declined to comment directly on the IUCN's review given that it is not a member of the network, but said debate within the International Whaling Commission (IWC) should take into account data on stocks. The IWC oversees the 1986 ban.
"There have been many moments at the IWC this year when debate was not directly linked to stocks," Shigeki Takaya, assistant director of far seas fisheries at Japan's Fisheries Agency told Reuters.
Norway has a quota of 1,052 minke whales and Iceland 40 in the north Atlantic in 2008. Japan caught 551 minke whales off Antarctica in the past season. Hunts used to be far bigger.
"This strengthens our opposition to whaling," said Frode Pleym of Greenpeace of the IUCN report. "While some species have started to recover, none of them are back to the levels they had before industrial whaling started."
The IUCN said many species were still in trouble. The blue whale, the largest creature ever to have lived on earth, remained "endangered" along with the fin whale and sei whale.
"Overall, nearly a quarter of cetacean species are considered threatened...nine species are listed as 'endangered' or 'critically endangered'," the highest levels of threat, the IUCN said in a statement.
Among those most at risk were the vaquita, a porpoise in the Gulf of California off Mexico, with only about 150 left in the wild. Reeves praised Mexico for a recent conservation drive.
(Additional reporting by Takanori Isshiki in Tokyo; Editing by David Fogarty)