and gray. Range The historic native range of the fluvial form of Montana Arctic grayling encompasses the mainstem and tributaries of the upper Missouri river as far downstream as the Great Falls. This range was isolated from the northern populations of Arctic grayling in Canada in the post glaciation period from southern populations in Montana and Michigan. The Michigan grayling (T. a. tricolor) is now extinct. During the 1804-1806 Lewis and Clark Expedition, the explorers did not encounter the Montana grayling until they reached the Beaverhead river, a secondary tributary of the Missouri. They described the grayling as "white trout". In 1915, U.S. Bureau of Fisheries biologist, W.C. Kendall described the Montana grayling as "abundant" in the Madison, Firehole and Gibbon rivers in Yellowstone National Park. These Missouri river headwaters represent the southern extent of the historic range in Wyoming. The introduction of non-native brook, brown and rainbow trout into the upper Missouri river basin which began in the 1890s initiated a severe decline in fluvial grayling populations and range. In Howard Back's 1938 work The Waters of Yellowstone with Rod and Fly, he lamented that he was unable to find any grayling in the Madison river. By the 1950s, the only grayling in the park were lacustrine forms introduced into Grebe lake. The native range of the adfluvial form was restricted to the Red Rock Lakes at the headwaters of the Beaverhead river and several small mountain lakes in the Big Hole River drainage. The current range of fluvial Montana grayling is restricted to approximately of the Big Hole river between Melrose, Wisdom and Jackson, Montana. The highest concentrations of grayling are in the Wisdom, Montana reach of the Big Hole river. This represents approximately four percent of the grayling's original native range. In the early 20th century fishery agencies began introduction of Arctic grayling in suitable lake environments in the state. Most of these introductions were from fluvial stocks that originated in Montana, however some introductions came from Arctic grayling populations in Alaska or Canada. In 1921, U.S. Fish Commission personnel stocked Grebe Lake, at that time fishless, with a lacustrine form of the Montana arctic grayling. The original stocks came from Georgetown Lake near Anaconda, Montana. In an effort to re-establish grayling in western states, over 72 million grayling eggs were harvested from Grebe Lake between 1931 and 1956 and distributed to hatcheries. Most lake dwelling grayling