Can Arctic Seals Survive This Century?
Author: Hien Thach, Edited by: Emilyann Ashford
The Arctic is the northernmost polar region of the Earth and consists of Alaska, Finland, Greenland, Iceland, Northern Canada, Norway, Russia, Sweden and the Arctic Ocean. Over the far northern regions of the Arctic Ocean, there is permanently frozen packed ice, also referred to as sea ice. In the southern regions of the Arctic Ocean, there is first-year sea ice, which forms during the Fall and Winter. However, due to increased climate change the first-year sea ice melts in the Spring and Summer. Both of these ice formations serve as habitats for arctic animals like polar bears, arctic foxes, walruses, and arctic seals. Melting of the first-year sea ice requires arctic animals to migrate in the spring and summer; north towards sea ice, or south towards surrounding Arctic land (1). The melting of this first-year sea ice can lead to a loss in population for some species and could even lead to extinction of species in the future due to climate change leading to habitat loss.
Global climate change has rapidly increased in the Arctic region, as a result sea ice is being impacted. According to IPCC 2007 climate models, which predicted the melting of ice will result in warmer temperatures in the Arctic, the thickness of the sea ice in the Arctic has decreased by about 40% between 1950s to the 1990s. Even surrounding land areas in the Arctic have been impacted due to global warming because of thawing permafrost, which is a layer of soil below the land areas that have been frozen for years (3).
The first-year sea ice is having a shorter season, and this specifically impacts arctic seals. These include ribbon seals, bearded seals, ringed seals, spotted seals, harp seals and hooded seals (4). Seals are most vulnerable during the Fall and Winter, when their predators are around and when they give birth, they focus on their pups and not their predators, leaving them unable to protect themselves (5). The diversity of seals in the Arctic is the greatest when there is first-year sea ice because predation is minimal. Predators of Arctic seals like polar bears and Arctic wolves, must migrate during the Spring and Summer to either surrounding land or sea ice, whereas Arctic seals are able to create a habitat for themselves on the first-year sea ice. Seals are also being impacted because they use the one-year sea ice to raise their young in lairs. As the one-year sea ice melts in the Spring and Summer, the roofs of their lairs collapse on premature seal pups. These seals are now in danger because they have no shelter and they are exposed to predators. Some mother seals even leave their pups in the water due to the melting of the one-year sea ice (1).
Figure 1. A seal taking care of its premature pup on the one-year sea ice (3).
The melting of one-year sea ice also decreases the intake of food by taking away the ability for Arctic seals to hunt. Arctic seals are agile swimmers and use this ability to hunt by catching fishes and crustaceans. Their thick coats of blubber allow them to stay underwater for about 15 minutes keeping them warm and serve as a source of nutrition when food resources are low. Seals build their own lairs or snow dens on the sea ice at breathing holes as a home. The lairs being on top of breathing holes allows the pups to be raised safely and throughout the Fall and Winter, the only way into the lair is through the breathing hole, most predators do not know this (5).
Figure 2. A seal in its lair, protecting its premature pup from predators (4).
A way to prevent climate change in the Arctic is to reduce greenhouse gas emissions to allow the conservation of Arctic marine mammals and ecosystems to survive a longer term (6). There are conservation efforts on the Arctic, the Arctic animals, and even specifically for Arctic seals. Some of these conservation efforts for Arctic seals are NOAA fisheries (committed to protecting harp seals), WWF (works with agencies and coastal communities to ensure that marine animals are sustainably managed), Seal Conservation Society etc. Measures can be taken to improve conditions for the Arctic ecosystems and their animals are either reducing climate change to eliminate the melting of one-year sea ice during the Spring and Summer or increase our anthropogenic efforts to save these Arctic seals.
Citations:
1. Allsopp, M., Santillo, D., & Johnston, P. (2012). Climate Change impacts on arctic wildlife. Greenpeace Research Laboratories.
2. Arctic Sea Ice Minimum. (2019, October 2). Retrieved from https://climate.nasa.gov/vital-signs/arctic-sea-ice/
3. “Harp seal.” Seal Facts and Information, www.seals-world.com/harp-seal/.
4. Joling, Dan. “Ringed Seals Threatened by Global Warming.” TahoeDailyTribune.com, TahoeDailyTribune.com, 22 Feb. 2007, www.tahoedailytribune.com/news/ringed-seals-threatened-by-global-warming/.
5. Kelly, B. P. (2001). Climate change and ice breeding pinnipeds. In “Fingerprints” of climate change (pp. 43-55). Springer, Boston, MA.
6. Ragen TJ, Huntington HP & Hovelsrud GK (2008). Conservation of Arctic marine mammals faced with Climate Change. Ecological Applications 18 (2): Supplement pp 166-174.