The Arctic Grayling

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Arctic Grayling
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Image of animal

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General Information;

Type: Fish
Diet: Omnivore
Size: 76cm (max)
Weight: 3.8kg (max)
Conservation status:

Scientific Classification: Kingdom: Animalia, Phylum: Chordata, Class: Actinopterygii, Order: Salmoniformes, Family: Salmonidae, Subfamily: Thymallinae, Genus: Thymallus
Size relative to a 6-ft (2-m) man: Not applicable
Arctic Grayling Range


The Arctic grayling is a species native to northern North America. The only populations native to the lower 48 states were in Michigan and Montana, and the Michigan population is now extinct. Consequently, the fluvial or river-dwelling population in the upper Big Hole River are the last remnants of this native Fish of Special Concern. Originally, the fluvial Arctic grayling was widespread throughout the upper Missouri river drainage as far downstream as Great Falls. Lewis and Clark made note of these "new kind of white or silvery trout" in 1805. The lake-dwelling form is fairly common in 30 or more lakes across the western half of the state. These lake fish are genetically, but not visibly, different from our native fluvial grayling. Grayling are gullible to the angler's lures and also seem to be easily out-competed by other salmonid species. This probably explains much of their demise from their native range. They are spring spawners and broadcast their eggs over a gravel bottom in moving streams. Grayling can overpopulate, producing severely stunted populations in some mountain lakes. Grayling are truly a unique Montana species.
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Physical Features;
The Arctic grayling comes in a wide array of colors. Coloration can vary from stream to stream. Their dorsal fins are typically fringed in red and dotted with large iridescent red, aqua, or purple spots and markings. These colorful markings are most dramatic on large grayling. Arctic graylings’ backs are usually dark. Their sides can be black, silver, gold, or blue. A band of gold forms a border between their sides and white bellies, which are in sharp contrast to their pelvic fins striated with iridescent orange, red, or pink. The sides of the body and head can be freckled with black spots. A black slash lies on each side of the lower jaw. The iris of their eyes is often gold in color. Only their adipose, caudal (tail), pectoral, and anal fins are without much color; typically dull and gray. Arctic grayling are larger and thicker than that of its cousins (salmon, trout, and char) and they sport a unique scalloped edge.
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Mental Features;
Arctic grayling spawn for the first time between the ages of 4 and 7 years and at a length of about 255 to 305 millimeters (~10 to 12 inches.) The eggs are about 2.5 millimeters (1/10 inch) in diameter and are slightly heavier than water, so they sink to the bottom; lodging in between pebbles and gravel. A female, depending on size, may have between 1,500 and 30,000 eggs. Because grayling live up to 32 years in Alaska, they may spawn many times during their life. Grayling fry hatch about three weeks after spawning and are akin to a short 13 millimeter (½ inch) piece of thread with two eyes.
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Diet;
During the brief summer, Arctic grayling are voracious feeders. They will eat almost anything that moves, but drifting aquatic insects, especially black flies, mayflies, stone flies, and caddis flies are their primary food items. At times, grayling will gorge upon the eggs of spawning salmon, smaller fish, or terrestrial (land) insects that have fallen into the water. They may even eat an occasional vole or shrew! One grayling had seven shrews in its stomach. Another’s stomach contained 65 chum salmon smolt (small salmon heading to sea). During winter, Arctic grayling feed minimally. They conserve energy by occupying lakes or the deeper, slow-current pools of medium-sized rivers such as the Chena and Gulkana, or in large glacial rivers like the Tanana, Susitna, and Yukon. Unlike many other fish, Arctic grayling can tolerate low dissolved oxygen levels (a common condition beneath the ice). This ability allows grayling to survive the long winters in areas where many other fish would die.
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Habitat;
Today Arctic grayling are found primarily small, cold, clear lakes with tributaries suitable for spawning. They do not coexist well with other fishes except cutthroat trout and others with which they evolved.
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Credits (c);

Images:
http://www.flickr.com/photos/fortsimpsonchamber/6455058423/

Information:
http://fieldguide.mt.gov/detail_AFCHA07010.aspx
http://en.wikipedia.org/wiki/Arctic_Grayling
http://en.wikipedia.org/wiki/Arctic_Grayling
http://www.adfg.alaska.gov/index.cfm?adfg=arcticgrayling.main
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