(AP) -- The overall number of animals in the Arctic has increased over the past 40 years ago, according to a new international study. But critters who live closest to the North Pole are disappearing.
The report by the United Nations and other groups released Wednesday at a conference in Miami concludes that birds, mammals and fish have increased by about 16 percent since 1970. That's mostly because of decades-old hunting restrictions. The number of geese have about doubled. Marine mammals, such as certain whales, are also rebounding.
The biggest improvement was in the lower regions of the Artic, where the number of animals, especially those that live in the water, are up about 46 percent.
However, scientists aren't celebrating the increase. Species in what is called the High Arctic dropped by a quarter between 1970 and 2004. North American caribou are down about one-third.
"What we're seeing is that there's winners and losers with rapid changes in the Arctic," said Mike Gill, a Canadian government researcher and study co-author. He's chairman of the international Circumpolar Biodiversity Monitoring Program, which organized the study.
Study author Louise McRae, a conservation biologist at the Zoological Society of London, said the drop in the High Arctic was most worrisome. That's because that region is the area where global warming occurs fastest and is projected to worsen, so the pressure on species will only increase, she added.
There's not enough evidence yet to blame global warming for the loss of species, but what is happening, is "largely in line with what would be predicted with climate change," Gill said.
The area with the biggest losses also has sea ice shrinking faster than predicted, and species like polar bears and whales called narwhals are dependent on sea ice, the report said.
The study compared how species were doing in the Arctic parts of three oceans. Species living in the Arctic portion of the Pacific Ocean were doing far better than they used to, while those in the northern parts of the Atlantic and the Arctic Ocean were not changed much over time, the report said.
Animals doing better include bowhead whales, white-tailed eagles, and the Atlantic Puffin. Those doing worse include the Atlantic cod, lemmings, the brown bear and the polar bear in the western Hudson Bay. The data on polar bears elsewhere isn't good enough to make any conclusions.
Explore further: UN moves toward major treaty for ocean biodiversity
More information: The Arctic Species Trend Index: http://www.asti.is/images/stories/asti%20report.pdf