 |
    |
 |
|||||||||||||||||
|
Yellowstone Cutthroat Trout Oncorhynchus clarki bouvieri Yellowstone cutthroat trout are a native species whose native distribution occurs on both sides of the Continental Divide from the upper Snake River above Shoshone Falls, to the Yellowstone River drainage downstream to the Tongue River, including Yellowstone Lake. Their natural range spreads across parts of Montana, Idaho and Wyoming, and very small portions of Nevada and Utah. The historical distribution of Yellowstone cutthroat trout is difficult to ascertain due to the movement of other trout species in the past, and it is worth noting the closely related Snake River finespotted cutthroat trout which apparently evolved from the Yellowstone cutthroat. Yellowstone cutthroat trout were heavily stocked throughout the West from 1905 to 1955, and are now considered introduced/invasive species in some locations.
Yellowstone cutthroat trout are spring spawners whose reproductive season extends from April to July depending on temperature. As in other cutthroat and rainbow trout species, Yellowstone cutthroats dig redds in stream beds where they lay and fertilize their eggs. Populations can live as either resident stream populations or in lakes where they must migrate up streams to spawn. Additionally, life histories in both age and size can vary greatly by population. Yellowstone cutthroat trout are threatened by a number of nonnative trout species that have been stocked throughout its range, mainly brook, brown and rainbow trout. Pollution of the gene pool from stocked rainbow and westslope cutthroat trout is also a major threat since these species readily hybridize where they overlap. The population in Yellowstone Lake is further imperiled by the illegal stocking of lake trout into the lake where they have since begun to thrive. As with most wild trout populations in the West, the Yellowstone cutthroat trout is susceptible to whirling disease, caused by the invasive Eurasian Myxobolus cerebralis parasite, where it occurs. There are a number of issues that threaten the continued existence of Yellowstone cutthroat trout in their native range, but there are also a number of conservation efforts that are underway to keep populations viable and to restore some populations to their former condition before human intervention. References:Behnke, R.J. 1992. Native Trout of Western North America. American Fisheries Society Monograph 6. Behnke, R.J. 2002. Trout and Salmon of North America. The Free Press, New York. Brown, C.J.D. 1971. Fishes of Montana. Big Sky Books, Bozeman. |
|
