Bearded seal. Photo: NOAA
Many seal species depend on sea ice for their survival. As global climate change reduces the extent, duration, and thickness of sea ice, these seal species are threatened with extinction.
As global warming worsens, the (un)natural mortality rate of the harp seals worsens, too. Harp seal mothers need large, sturdy ice floes to give birth to their pups since pups do not know how to swim for the first few weeks of their lives.
The 21st century has seen year after year of poor ice, sometimes leading to the drowning of almost all seal pups born in the Gulf of St. Lawrence, one of the main nurseries for harp seals.
In 2016, this ice report was provided by the National Snow and Ice Data Center (NSIDC), a U.S. agency supported by NASA, NSF, NOAA, and other government agencies:
"Arctic sea ice extent during January averaged 13.53 million square kilometers (5.2 million square miles), which is 1.04 million square kilometers (402,000 square miles) below the 1981 to 2010 average. This was the lowest January extent in the satellite record, 90,000 square kilometers (35,000 square miles) below the previous record January low that occurred in 2011. This was largely driven by unusually low ice coverage in the Barents Sea, Kara Sea, and the East Greenland Sea on the Atlantic side, and below average conditions in the Bering Sea and Sea of Okhotsk. Ice conditions were near average in Baffin Bay, the Labrador Sea and Hudson Bay. There was also less ice than usual in the Gulf of St. Lawrence, an important habitat for harp seals."
Other ice seals threateded by climate change include bearded seals and ringed seals. Both species are now listed as threatened in the U.S., due to the threat of climate change to their survival.
|Harp seals depend on sea ice for pupping. In the first weeks of life, seal pups can't swim. This seal pup was in trouble as the ice around it crumbled. Photo by IFAW.
Seals of the Arctic
Six seal species live in the Arctic region: bearded seals, harp seals, hooded seals, ribbon seals, ringed seals, and spotted seals. Bearded seals, harp seals, and ringed seals are especially vulnerable to disappearing sea ice.
Bearded seals and ringed seals give birth on dense ice packs or on "fast ice", ice usually located over shallow parts of the ocean that is 'fastened' to the ocean floor or shore, such that it does not drift in the wind. They also require snow cover on the ice to build lairs for giving birth.
Click on picture for larger image
Harp seals follow the sea ice all year, migrating south from the Arctic in the spring. The seals give birth off the coast of Norway and Newfoundland and Labrador, in Russia's White Sea, and in the Gulf of St. Lawrence of Canada. The pups begin life unable to swim. Thus they require sturdy sea ice during the birthing season in February and March.
In recent years, thousands of harp seal pups have drowned due to insufficient and broken up sea ice. Unusually poor ice conditions have been reported in 2006, 2007, and almost each year from 2010 on.
Click on picture for larger image.
In 2011, the ice floes were in very poor condition. The February 2011 ice cover was the worst in recorded history, but this did not stop the Canadian government (i.e., the Department of Fisheries and Oceans, DFO, led by Minister Gail Shea) from setting an astronomical quota on the killing of harp seal pups.
In the end, a fraction of these seals were killed as a result of the closing of pelt markets.
Read about the 2011 seal hunt here.
Read the latest news on seals and sealing in Canada here.
The animal protection organization IFAW worked with Duke University scientists on a study of the harp seal population and the current and projected future effects of climate change on the species. Read about the Duke/IFAW study here. A follow-up study investigated causes of harp seal strandings and found increased strandings of harp seal pups in years with poor sea ice. It also found that young males stranded more frequently than young females.
MEAT COVE — Poor ice conditions in the southern Gulf of St. Lawrence are likely to endanger this year’s harp seal pups. Cape Breton Post, March, 2011
Read the published report on the study about the effects of climate change on harp seals here.
Even the scientists of the Canadian Department of Fisheries and Oceans (DFO) have reported that the population is now in decline.
Harpseals.org believes that the future of harp seals is in peril and that it is high time that the government of Canada work to protect seals and ban the killing of seals once and for all.
NOAA Fisheries lists ice seals as threatened, endangered
Dec. 21, 2012
A ringed seal pup peeks out from its protective snow cave near Kotzebue, Alaska. Photo: Mike Cameron, NOAA's National Marine Mammal Laboratory
After two years of study and public comment, the U.S. agency, NOAA fisheries, announced that it was listing four subspecies of ringed seals and two distinct population segments of bearded seals under the Endangered Species Act.
NOAA will list the Beringia and Okhotsk distinct population segments of bearded seals and the Arctic, Okhotsk, and Baltic subspecies of ringed seals as threatened. It will list the Ladoga subspecies of ringed seals as endangered.
The reasons NOAA cites for the listings are
• Under the ESA, a threatened species is likely to become endangered within the foreseeable future throughout all or a significant portion of its range. An endangered species is in danger of extinction throughout all or a significant portion of its range.
• Ringed and bearded seals are particularly dependent upon ice and snow for survival. Many aspects of the ringed and bearded seal’s life cycles depend on the availability of suitable ice, and for ringed seals snow cover, at the right time of the year in areas with sufficient food.
• Climate models consistently project diminishing ice and snow cover at least through the current century, with regional variation in the timing and severity of those losses.
• Although ringed and bearded seals are currently numerous in Alaska, NMFS has concluded that the changes in ice, and for ringed seals snow cover, are likely to lead to population declines in the foreseeable future and pose significant long-term threats to the persistence of these seals.
Contrast this with the actions of the Canadian government in managing the ice seals (i.e., harp seals) in its waters: instead of designating the species as protected, it spends millions of taxpayer dollars to massacre the seals.
Seals of the Antarctic
A Weddell seal
Six seal species live in the Antarctic: Antarctic fur seals, crabeater seals, elephant seals, leopard seals, Ross seals, and Weddell seals.
Crabeater seals, leopard seals, Ross seals, and Weddell seals give birth on sea ice and are thus at risk of exctinction as temperatures warm and the formation of sturdy sea ice becomes less reliable.
As the chart below, from NOAA, shows, Antarctica is losing ice mass at a disturbing rate. Click on the image for a larger view.
In the 1800's and 1900's explorers found large populations of seals in Antarctica. Sealers then proceeded to kill so many seals that populations of some of these species, including the Antarctic fur seal, were driven nearly to extinction. Today these seals are no longer exploited, and their populations have increased.
Change in Antarctic ice mass over time. NOAA
Other threats to the survival of seals
In addition to the lack of sea ice, some species of seals and other marine mammals are threatened by reductions in the availability of prey. Prey populations are affected by climate change and shorter-term climate effects like El Niño, over-fishing, and ocean pollution. A reduction in the abundance of plankton affects life up the food chain.
Click here for additional information and a pictorial description of predator-prey effects with grey seals.
Seals are victims of the fishing industry in other ways, too. Seals are injured and die from entanglement in fishing gear. Sometimes, they are shot by fishermen who consider them a nuisance or competitor.
Seals and sea lions of the United States
Sea lions are also pinnipeds and are in the same family as Cape fur seals. In the U.S., sea lions have been designated as threats to salmon and have been targeted for killing and relocated to zoos by the National Marine Fisheries Service. Read more about this controversy here.
Sea lions and seals in the U.S. have suffered from starvation in large numbers in recent years. This is due to prey migration due to climate change and El Niño. Pollution and toxic algal blooms that result from warming also have sickened and killed seals and sea lions.
Seals are an important part of the ocean ecosystem
Seal conservation is about far more than saving seals and stopping the Canadian seal slaughter. It is about saving marine ecosystems, of which all seals are an integral part.
Historical records from the time Europeans arrived in Newfoundland demonstrate that, without interference from these immigrants, seal populations much larger than that remaining today coexisted with cod so abundant that ships had difficulty maneuvering through the waters.
Today, conservation issues in the Arctic and North Atlantic region include the effects of large-scale commercial fishing, using such methods as bottom trawling and long-line fishing; global climate change, including changes in ocean currents, carbon dioxide concentration, and temperature; increased ship traffic as a result of decreases in sea ice; ocean pollution; and sealing.
The following are links to programs that may be of interest to those who wish to study marine ecosystems and marine mammal conservation:
Institute for Marine Mammal Studies
Woods Hole Oceanographic Institution
University of Miami Rosenstiel School of Marine and Atmospheric Science Marine Mammal Program
Other links to societies and graduate programs from the Society for Marine Mammology