14 



River immediately downstream from Libby Dam in August, 1971. 

 These allowed an assessment of the damage Montana is sustaining 

 from the gas super saturation problem in Kootenai River. This 

 problem was created when Libby Dam was closed in late March, 

 1972. 



The hatchery water supply at Big Spring Creek Trout Hatchery, 

 Lewistown, was renovated. Provision was made so only spring water 

 can be taken into hatchery raceways thus eliminating annual high 

 water flooding from the creek. Creek water can still be used as 

 needed. 



Fish hatchery production schedules were rearranged so a 

 substantial initial plant of westslope cutthroat trout could 

 be made in the newly formed Lake Koocanusa. 



Studies on Madison River and O'Dell Creek indicate that sub- 

 stantial plants of catchable-size hatchery trout cause summer 

 mortalities in wild trout. Since few planted fish survive over 

 winter, the net result is a measurable reduction in the trout 

 population. The implication, if these results are borne out in 

 other studies, is that "put and take" planting should be restricted 

 to waters with insignificant wild trout populations. 



