River drainage. The range of the westslope was severely reduced in 

 a mere 30-year period beginning in the mid 1900s. Unhappy with 

 the size and sporting nature of the "natives", settlers introduced 

 rainbow, brown, and brook trout into Montana's waters. Habitat 

 destruction through logging, mining and agricultural practices 

 also took its toll. The genetic differences between the two 

 subspecies also went unrecognized as Yellowstone cutthroat and 

 rainbow trout continued to be stocked on top of westslope, causing 

 extensive interbreeding. Although populations appeared to be 

 thriving, genetic purity and vigor was being lost. 



Ecological and genetic research in the last 25 years has led 

 to major changes in the state's fisheries management in an effort 

 to preserve and maintain the native cutthroat species. The 

 genetic differences between the westslope and Yellowstone were 

 finally identified in the 1960s. For much of the state, however, 

 their ranges had been severely reduced, with populations only 

 being found in headwater areas of smaller tributaries. In the 

 Flathead, where westslope populations were probably their 

 strongest historically, the decisions that were made to reverse 

 the process worked. The first step was to change the cutthroat 

 brood stock in all northwest hatcheries to pure westslope. An 

 intensive effort to determine genetic purity in the remaining 

 cutthroat populations through genetic investigation was then 

 begun. Once a pure population was identified, restoration 

 occurred through habitat protection, maintenance of barriers to 

 prevent potential genetic invasion, and strengthening of 

 populations through hatchery plants, where necessary. Habitat 

 protection has been secured through wilderness designation in the 

 South and Middle forks, and further protection will occur in the 

 North Fork and Swan River drainages if pending wilderness 

 legislation is passed. 



The substantial amount of data collected over the last 10 

 years by regional and contract fisheries staff contributed to the 

 high habitat and species values found in the upper Flathead. Only 

 seven percent of the identified reaches could not be rated due to 

 insufficient fisheries information, compared to 61 percent of the 

 Clark Fork drainage reaches with insufficient fisheries data. 

 Intensive surveys of other western drainages could expand the 

 current identified range of the westslope. 



While maintaining the highest number of stream reaches in the 

 state with a Class III or better in the habitat and species value, 

 the Flathead holds the fourth lowest number of miles with a rating 

 of Class III or lower in the sport fishery category. The sport 

 fisheries of the Flathead are dependent upon adfluvial populations 

 of westslope cutthroat and bull trout and kokanee migrating from 

 Flathead Lake to spawn in the main stem and its tributaries. Due 

 to a short growing season, cold water temperatures and naturally 

 unproductive waters, resident stream populations are generally 

 slow-growing with low biomass, therefore not attracting 

 considerable angling attention. The 80 miles of Class I sport 



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