Officially designated as Montana's state fish, the Westslope Cutthroat's historical range included all of Montana west of the Continental Divide, as well as the upper Missouri River drainage. The average size of these fish is 6 to 16 inches, depending on habitat. It is often difficult to distinguish the westslope from other cutthroat species, but it tends to have more small spots by the tail and none by the pectoral fin. Also, the Westslope Cutthroat Trout is more of a silvery or greenish color than other cutthroats.
Although commonly associated with the state of Montana, the historic range of Westslope Cutthroat Trout (Oncorhynchus clarkii lewisi) is the most widespread geographically among the 14 subspecies of inland cutthroat trout. Westslope Cutthroat Trout (WCT) are native to streams and lakes in the upper Columbia River basin (Idaho and Montana), the Methow River and Lake Chelan drainages (Washington), the John Day River drainage (Oregon), the headwaters of the South Saskatchewan River (Montana), and the upper Missouri River basin (Montana and Wyoming). WCT currently occupy about 33,500 miles (59%) of the nearly 56,500 miles of historical habitat.
The introduction and spread of nonnative trout such as brook, rainbow, brown, and lake trout is considered by many fisheries scientists to be the major threat to WCT. As with other cutthroat subspecies, the distribution and numbers of WCT have declined due to human influences such as livestock grazing and other agricultural practices, logging, road-building, mining, dam construction, loss of riparian habitat, erosion, sedimentation and placement of barriers to fish migration. The inability to stop or reverse habitat degradation is one of the major obstacles to the continued improvement of the WCT status, although this concern is ameliorated somewhat by the fact that over 50% of current occupied WCT habitat is in roadless and wilderness areas. In 2003, on the basis of the available information, the U.S. Fish and Wildlife Service concluded that the WCT is not likely to become a threatened or endangered species within the foreseeable future.
At present, there are multiple State, Federal, Tribal and private conservation efforts that are working to improve the status of WCT in the northwestern U.S. Projects have generally followed a site- specific/opportunity- based approach rather than a watershed approach, with varied results and accomplishments.
Since 2006, the Western Native Trout Initiative has contributed over $347,000 to 11 projects benefiting Westslope Cutthroat Trout in Idaho, Oregon, Montana and Washington. Projects have included a 2009 rangewide status assessment, numerous barrier removal efforts, as well as stream and riparian restoration.
Learn more about Washington Department of Fish and Wildlife's Westslope Cutthroat Trout management
Read the Idaho Fish and Game Department Management Plan for Westslope Cutthroat Trout conservation
Learn more about Montana Fish Wildlife and Parks' Westslope Cutthroat Trout conservation efforts
Learn more about Oregon Department of Fish and Wildlife's Native Fish Investigations Project
Read more about Oregon Department of Fish and Wildlife's Westslope Cutthroat Trout conservation
These photos are of Methow River (Washington) Westslope Cutthroat trout. All photos were taken by Kevin van Bueren of North Cascades Fly Fishing.
The photo below is of a Westslope Cutthroat Trout caught and released in July 2015 on the South Fork Salmon River near McCall, Idaho.