Polar bear sea ice habitat near the end of Arctic spring 2023

Arctic sea ice is beginning to melt and the end of spring is drawing near. Mating season is over for polar bears as is the gorging on young seals in most regions as weaned pups head into open water to feed for themselves. Only predator-savvy adult and subadult seals remain on the ice while they moult a new hair coat, so successful hunts by most polar bears will become more and more uncommon (e.g. Obbard et al. 2016).

Arctic sea ice overall

Sea ice thickness

Where red bits are 5m thick and even the green/yellow is 2.5-3.5m. This thick ice is not likely to melt over the summer but it can get broken up and flushed out of the Arctic by winds and currents, where it will melt in warmer waters.

The graph below shows that sea ice extent for May 2023, according to NSIDC compared to previous years, is only slightly less than it was in 1989 and 1995:

Sea ice Canada

Open water leads and polynyas in the sea ice, which are clearly visible in the ice chart below, are now important areas for polar bears to attempt to hunt, because these highly productive areas attract seals (Stirling et al. 1981).

Barents and Kara Seas, East Greenland

Svalbard subregion

Ice extent around Svalbard is declining, as it does every year about this time:

However, there is still abundant ice in the eastern and northern regions around Svalbard for polar bears to continue hunting attempts:

References

Obbard, M.E., Cattet, M.R.I., Howe, E.J., Middel, K.R., Newton, E.J., Kolenosky, G.B., Abraham, K.F. and Greenwood, C.J. 2016. Trends in body condition in polar bears (Ursus maritimus) from the Southern Hudson Bay subpopulation in relation to changes in sea ice. Arctic Science 2:15-32. 10.1139/AS-2015-0027 http://www.nrcresearchpress.com/doi/abs/10.1139/AS-2015-0027#.VvFtlXpUq50

Stirling, I, Cleator, H. and Smith, T.G. 1981. Marine mammals. In: Polynyas in the Canadian Arctic, Stirling, I. and Cleator, H. (eds), pg. 45-58. Canadian Wildlife Service Occasional Paper No. 45. Ottawa. Pdf of pertinent excerpts from the Stirling and Cleator volume here.