Walruses as polar bear prey and sea ice were on my mind last night and I remembered that we DO have detailed sea ice information for 1978 and 1972 – from the sea ice atlas put together by University of Alaska Fairbanks (UAF), which has ice concentration maps for Alaska going back to 1850 — and for every year up to 2013 (reported previously here).
Chukchi Sea walrus, June 2014. US Fish and Wildlife Service.
I’ve copied some of the ice maps below.
It is clear that ice was available close to Wrangel Island in 1972 when walruses chose to haul out on the island in huge numbers. And in 1978, there was ice present to the north of the walrus herd, but they had moved away from the ice to get to St. Lawrence Island, where they hauled out in large numbers.
This means it is more likely that food resources were the issue, not sea ice.
UPDATE OCTOBER 3 2014:
See another interesting follow-up elsewhere: Walrus inconsistencies
Posted in Life History, Sea ice habitat, walrus
Tagged Chukchi Sea, climate change, Fay, global warming, ice levels, Kelly, mass mortality, Point Lay, sea ice atlas, sea ice declines, sea ice maps, St. Lawrence Island, stampede, UAF, walus, Wrangel Island, WWF
It’s here – as promised and right on schedule — the sea ice atlas put together by University of Alaska Fairbanks (UAF) now has ice concentration maps for Alaska going back to 1850 — and for every year up to 2013.
Several examples are included below: August 1850 vs August 1870, and April 1850 vs. April 1920 and April 2012.
For background, see my post announcing the site preview, which was then limited to 1953-2012 data, when it became available in late January.
Posted in Conservation Status, Sea ice habitat
Tagged Alaska, Beaufort, Bering, Chukchi, historical sea ice, past polar bear habitat, polar bear, polar bear habitat, sea ice atlas, sea ice concentration, sea ice maps, UAF, University of Alaska Fairbanks