Great Bear Lake
Great Bear Lake is a significant freshwater lake located in Canada's Northwest Territories, recognized for its pristine condition and ecological importance. Covering approximately 12,000 square miles (31,000 square kilometers), it is one of the deepest lakes in the world and is situated partially within the Arctic Circle. The lake features a unique shape with five main arms and is surrounded by boreal forests and tundra, providing a rich habitat for diverse wildlife. Known for its cold temperatures and slow-growing fish, Great Bear Lake is renowned as a premier fishery, particularly for lake trout and Arctic grayling, with strict regulations in place to protect its delicate ecosystems.
Historically, the area has been inhabited by Indigenous tribes, notably the Satudene, who have a deep cultural connection to the lake. European influence began in the late 18th century with fur trading, followed by mining activities in the 20th century. Despite past human activity, the lake remains largely unaltered and free from significant pollution. However, it faces potential threats from climate change, which could disrupt its fragile ecosystems and influence water temperatures and wildlife habitats. UNESCO recognized the lake as a biosphere reserve in 2016, highlighting its ecological significance and the need for continued conservation efforts.
Subject Terms
Great Bear Lake
- Category: Inland Aquatic Biomes.
- Geographic Location: Canada.
Summary: This natural water body in the far north has remained nearly unaffected and unaltered by humans and is believed to be the largest freshwater lake in the world with this degree of pristine character.
Great Bear Lake is located in Canada's Northwest Territories, with its northern waters within the Arctic Circle. This vast boreal pool is considered among the most pristine freshwater bodies in the world; its remote position has helped protect both its water and its habitats from degrading by human interaction. Yet its biological character, formed in extreme cold conditions, may prove somewhat fragile under the rigors of global warming. In 2016, UNESCO declared the lake and its watershed a biosphere reserve, named Tsá Tué.
Geography and Climate
Smaller than the Great Lakes Superior or Huron, but the largest freshwater lake completely within Canada, Great Bear Lake was carved by glaciers during the most recent ice age. The lake has a surface area of approximately 12,000 square miles (31,000 square kilometers). It is one of the deepest lakes in the world, with a mean depth of 235 feet (72 meters), with its deepest point at 1,460 feet (446 meters). Scattered with numerous small islands, Great Bear Lake is shaped like a jigsaw puzzle piece (similar in shape, some say, to the Starship Enterprise) with five main arms extending from the center. The arms of the lake are named McVicar, McTavish, Keith, Smith, and Dease. The longest stretch across is roughly 190 miles (300 kilometers) from the far reaches of one arm to another.
Great Bear Lake drains into the Mackenzie River, which flows northwest and is joined by the Arctic Red and Peel Rivers, before finally emptying into the Beaufort Sea, a part of the Arctic Ocean. The drainage basin for the lake is approximately 44,400 square miles (115,000 square kilometers). Great Bear Lake lies across two chief physiographic regions: the Canadian Shield and the northern Interior Plains. Boreal forests of the taiga surround the lake, and its northernmost arm reaches into the tundra.
Great Bear Lake temperatures are very cold except during the very brief subarctic summer. During this short summer—the lake is typically covered with ice from late November through July—the lake's surface temperature remains at or below 39 degrees F (4 degrees C). Great Bear is a polar, or cold, monomictic lake, meaning that its water mixes thoroughly from top to bottom only once a year, when it lacks ice cover and then has relatively uniform temperature and density at all depths.
Wildlife
Commercial fishing is prohibited, and sport fishing is closely regulated on Great Bear Lake, because of the slow regeneration of the fish in the icy water. As a result of the temperature and depth of the waters, fish here grow slowly; because of this slow growth rate, it is estimated that some fish found in Great Bear Lake can be over 100 years old. The trout of Great Bear Lake can take anywhere between 15 and 26 years to reach sexual maturity, and only spawn once every two to three years.
To protect stocks from becoming endangered, sport fishing remained heavily regulated. Lake trout, lake whitefish, Arctic grayling, Arctic char, walleye, and northern pike are some of the noted species found in the lake. Great Bear Lake has a significant reputation as the greatest trout and Arctic grayling fishery in the world, with world records (in size and weight) held for both.
Surrounding the southern and western shores of the lake are boreal forests, largely of black and white spruce, interspersed with muskeg in the lower-lying, poorly drained regions. To the north the forest declines, as it gives way to tundra. The shores of Great Bear Lake are rich in wildlife, and since there is little interaction with or interference from humans, this ecosystem remains virtually unaltered. Animals that inhabit the lake's surrounds include musk ox, moose, Dall sheep, mountain goat, woodland caribou, barren-ground caribou, black bear, grizzly bear, bald eagle, golden eagle, gyrfalcon, elk, martens, and numerous types of waterfowl.
Human Impact
The Great Bear Lake area's first known inhabitants were Indigenous tribes of the Athabaskan language group: the Hare, Mountain (known also as Slavey or Slave), Dogribs, and Copper tribes together making up a group recognized as the Satudene, derived from words in Chipewyan meaning bear water people. These distinct groups inhabited and hunted in various areas around the lake and to the south toward Great Slave Lake.
In 1799, the first European settlers arrived in the form of explorer Alexander Mackenzie, his partners, and their fur trading company, the North-West Fur Company. This company, a rival of the Hudson's Bay Company, merged with it in 1821. Except for fur trading posts, settlements were scarce around the Great Bear Lake until the discovery of pitchblende, silver, and cobalt in 1930. A mine was established, extracting radium from the pitchblende deposits; the associated uranium ore was discarded as of little commercial value. The mine eventually closed, but was reopened in 1942 to supply uranium for the Manhattan Project. Quantities of uranium, having previously been dumped in the lake, were recovered by dredging. This mine was closed in 1964, but certain workings were maintained for the extraction of silver.
The only permanent settlement in the region is in Délįne, with a population of just over five hundred people, mainly of Satudene heritage. There are fishing lodges in various locations around the lake, accessed by airplane. Most of the year, there are very few viable roadways. There is no current evidence of siltation, toxic contamination, eutrophication, or acidification in Great Bear Lake.
However, northern Canada has already experienced some of the most extreme climate change effects on the planet. Concern remained that the pristine nature of the lake and its aquatic ecosystems could be compromised as temperature, humidity, and precipitation regimes deflected from their ages-old patterns. Scenarios Network for Arctic Planning assessed climate change on Great Bear Lake in 2011 and reported that the Lake's watershed was expected to become warmer. Additionally, winters were expected to grow shorter and less severe. Both increases in precipitation and the thawing of permafrost were considered likely. Habitats here, and species with their extenuated growing cycles, would be hard-pressed to adapt and adjust to the dramatic changes from global warming.
Bibliography
Déline Renewable Resources Council. "Great Bear Lake Climate Change Analysis: An Assessment of Climate Change Variables in the Great Bear Lake Region, Canada." Scenarios Network for Arctic Planning, Mar. 2011, uaf-snap.org/wp-content/uploads/2020/06/finalreport.pdf. Accessed 3 Nov. 2024.
"Great Bear Lake." The Canadian Encyclopedia, 21 Sept. 2021, www.thecanadianencyclopedia.ca/en/article/great-bear-lake. Accessed 8 Nov. 2024.
Johnson, Lionel. "The Great Bear Lake: Its Place in History." Arctic, vol. 28, no. 4, 1975, pp. 231–44.
Likens, Gene E. Lake Ecosystem Ecology: A Global Perspective. Academic Press, 2010.
"Odd Fish Has Adapted to Canada's Deepest Coldest Lakes." Science Daily, 5 July 2022, www.sciencedaily.com/releases/2022/07/220705162241.htm. Accessed 3 Nov. 2024.
"Tsá Tué." UNESCO, www.unesco.org/en/mab/tsa-tue. Accessed 8 Nov. 2024.
Vincent, Warwick F. Polar Lakes and Rivers: Limnology of Arctic and Antarctic Aquatic Ecosystems. Oxford UP, 2008.