Arctic grayling have elongated and trout-like bodies. Like other salmon, they have short heads, large eyes, small, toothed mouths, and forked tails. Arctic grayling are 15 to 36 cm long, with an average weight of 1 to 2 kg. The largest individual on record was around 76 cm long and 3.8 kg. They have dark colors on their backs, from dark purple to blue grey. Their sides are gray or blue with patterns of v-shaped markings. Males are often more brightly colored than females. The fins can have bright pink and orange stripes on them. ("Arctic Grayling (Thymallus arcticus)", 2013; "Arctic Grayling Recovery", 2012)
Arctic grayling are found throughout the much of the northern hemisphere, including northern Canada, Alaska, and Siberia. They were once found throughout the Arctic as far west as the Kara River in Russia, as far east as the western shores of the Hudson Bay in Canada, and as far south as Michigan. Though they no longer occur naturally in North America apart from Canada and Alaska. They have been introduced into high elevation lakes of the western mountain states, such as Arizona and California, and the upper Missouri River drainage in Montana. (Sepulveda, et al., 2013; Stamford and Taylor, 2004)
Arctic grayling live in high-elevation, mid to large, cold and clear freshwater lakes and rivers. In the early spring, they migrate from overwintering areas to rocky streams for spawning. They then move to summer feeding areas before finding a suitable wintering spot, where they spend 8 to 9 months under ice. (Baccante, 2011; Hughes and Reynolds, 1994)
Arctic grayling fry hatch 2 to 3 weeks after spawning, and they are approximately 1.3 cm long at hatching. The fry immediately move toward the calm and warm shoreline waters where they will become juveniles at 5 to 10 cm by the end of summer. They continue to grow quickly and reach maturity in 3 to 4 years. At this point, they begin to grow much more slowly as they dedicate more of their annual energy intake to spawning efforts. ("Arctic Grayling (Thymallus arcticus)", 2013; Wedekind, et al., 2013)
Arctic grayling spawn in spring in shallow areas of rivers with moderate current as well as a gravel or rocky areas and fine sand sediments. Males court females by flashing their colorful dorsal fins. The eggs are dropped onto the river bottom and are left there to develop. (Kratt and Smith, 1980)
Arctic grayling lay eggs in the spring, when ice begins to break up. Depending on the size of the female, she may lay between 1,500 and 30,000 eggs. The eggs sink to the bottom and become lodged between pebbles and gravel. Only about 10% of the fry that hatch from the eggs will reach adulthood and be able to spawn. ("Arctic Grayling (Thymallus arcticus)", 2013; Kratt and Smith, 1980)
The lifespan of arctic grayling is usually around 18 years for both males and females. However, individuals in Alaska have been known to live up to 32 years. Most mortality occurs in eggs, larvae, and fingerlings or in areas where these fish are heavily fished. ("Arctic Grayling (Thymallus arcticus)", 2013; "Arctic Grayling Recovery", 2012)
Arctic grayling migrate between streams used for spawning, development, summer feeding, and overwintering in order to survive in their harsh arctic habitats. Some individuals, however, are sedentary. They are active during the day. (Davis, et al., 2010; Gingerich, et al., 2010)
Arctic grayling may move tens of miles on a seasonal or annual basis between spawning, feeding, and sheltering habitats. Some arctic grayling have been known to travel more than 160 km (100 miles) in one year. (Davis, et al., 2010; Gingerich, et al., 2010)
There is little information on arctic grayling communication and perception. But, like other freshwater fish, they probably use a lateral line system that detects pressure changes in the water and they are also likely to be able to detect chemical cues in the water. They are visual predators, reacting to visual cues to detect and attack prey. (Bleckmann and Zelick, 2009)
During the brief northern summers, arctic grayling eat drifting aquatic insects, such as black flies, mayflies, stoneflies, and caddisflies. At times, they eat eggs of spawning salmon, smaller fish, or terrestrial insects that have fallen into the water. They may even eat an occasional vole, lemming, or shrew. Young arctic grayling feed on zooplankton and eventually transition to feeding on insect larvae. ("Arctic Grayling Recovery", 2012; Davis, et al., 2010)
Arctic grayling are one of the top predators in their aquatic habitats. They prey on a wide variety of insects, fish and other small animals. They are also hosts to several parasite species. (Arai and Mudry, 1983; Davis, et al., 2010; Muzzall, 1990)
There are no known adverse effects of arctic grayling on humans.
Arctic grayling are raised commercially for food and fished for sport. ("Arctic Grayling (Thymallus arcticus)", 2013)
While arctic grayling are not currently considered endangered, they are sensitive to pollution in the areas they live. They are most vulnerable to overfishing, competition, road culverts, mining, agriculture, and destructive forestry practices. Recent findings suggest that arctic grayling populations may be in decline and need protection. ("Arctic Grayling (Thymallus arcticus)", 2013)
Michael Hsieh (author), The College of New Jersey, Keith Pecor (editor), The College of New Jersey.
Alaska Department of Fish and Game. Arctic Grayling (Thymallus arcticus). Anchorage, Alaska: Alaska Department of Fish and Game. 2013. Accessed October 15, 2013 at http://www.adfg.alaska.gov/index.cfm?adfg=arcticgrayling.main.
US Fish & Wildlife Service. Arctic Grayling Recovery. Washington, DC: US Fish & Wildlife Service. 2012. Accessed October 15, 2013 at http://www.fws.gov/redrocks/arcticgrayling/.
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