The “classic” Arctic ice seal in a changing climate
Ringed seals are the “classic” Arctic seal in many regards, extent and season have potentially dire consequences for
being found as far north as the Pole because of their ability both of these Arctic animals.
to keep breathing holes open in ice that can reach 2 metres
in depth. This species is certainly one of the most vulnerable
of the high-Arctic seals to the declines in the extent or quality
of sea ice because so many aspects of their life-history and
distribution are tied to ice.
Ringed seals also require sufficient snow cover on top of the
ice to construct lairs for resting, giving birth and caring for
their young (Figure 5.16). The pups are born weighing only
4 kg and both ice and snow must be stable enough in the
spring season to successfully complete the six week lactation
period
73
. Premature break-up of the land-fast ice can result in
the pups being separated from their mothers, leading to high
rates of pup mortality
74,75
. Spring rains, or high temperatures
in spring, can cause the roofs of lairs to collapse, leaving
ringed seals subject to increased predation and risks from ex-
posure
76
. Years in which insufficient snowfall takes place prior
to breeding results in a similar phenomenon
77
.
Figure 5.16: Ringed seal pupping lair, with the pup in the lair
and the female approaching the haul-out hole from the water.
Ringed seals are the principle prey for the top predator in the
Pups excavate the side tunnels.
Arctic food chain – the polar bear. Declining sea-ice quality, Source: R. Barnes, based on Gjertz and Lydersen 1983
78
rate and extent of decreases in the reach of Arctic sea their denning areas and again in the spring when they
ice in the coming decades represents major challenges leave the dens with their cubs and travel to the prime
to Arctic seals. hunting grounds along the northern ice edge.
Polar Bears Concerns regarding the impacts of climate change on polar
This largest member of the bear family is a sea-ice spe- bears have been voiced since the time of the first suggestions
cialist. Ice-dwelling seals make up the majority of the that Arctic sea ice was thinning and becoming reduced in
polar bear’s diet. Like their seal prey their continued extent and season
79
. Prolongation of the ice-free period was
existence probably depends on the availability of their seen immediately as a threat to polar bears. During the past
primary habitat – the Arctic sea ice. In some parts of the decade it has become increasingly clear that polar bears are
Arctic, polar bears build their maternity dens in snow already showing declines in body condition and reproduc-
drifts on multi-year sea ice. In other areas where dens tive output that are attributable to physical changes in the
are usually located on islands, the bears are still depend- southern parts of their range, particular the decline in the
ent on the availability of sea ice in the autumn to reach duration of the sea-ice season
80–83
.
84 GLOBAL OUTLOOK FOR ICE AND SNOW