trout. It is known that planted trout from Noxon 

 Rapids have moved downstream into Cabinet Gorge 

 Reservoir and on into the lower Clark Fork River 

 and Lake Pend Oreille in Idaho. Research has in- 

 dicated that the main factors influencing this down- 

 stream movement of planted rainbow trout may be 

 the reservoir fluctuation, type of drawdown, and 

 time of drawdown. 



The future of the Noxon Rapids fishery and simi- 

 lar fisheries lie, to a good part, in the ability of the 

 game fish to successfully spawn. Surveys of streams 

 tributary to Noxon Rapids have shown that very- 

 few of the planted rainbow trout entered these 

 streams to spawn. To aid the establishment of spawn- 

 ing runs of rainbow trout in Noxon Rapids, 400,000 

 eyed rainbow eggs were planted in two tributary 

 streams. These fish, having been hatched in a 

 stream, may have developed facilities to enter that 

 stream upon reaching spawning size and age. The 

 results of these egg plants can not be determined 

 until the spring of 1963 or 1964 when the fish reach 

 spawning age. 



Brown trout and Dolly Varden have re-established 

 spawning runs in three Noxon tributaries. These two 

 species spawned in the same streams before the 

 completion of Noxon Rapids in 1958. 



Planting of 150,000 sub-catchable size rainbow 

 trout continued in Cabinet Gorge in 1960 and 1961. 

 These hatchery fish, along with escapement from 

 Noxon Rapids Reservoir, produced excellent angling 

 in I960 and 1961. Fishing success during the early 

 months of 1962 showed a decline as compared to the 

 previous two years. 



The 1959 and 1960 planting of rainbow trout in 

 this reservoir increased the percentage of rainbow 

 trout in the total population. Rainbow trout comprised 

 less than one per cent in 1959, 20 per cent in I960, 

 and 10 per cent in 1 96 1. Initial 1962 information 

 indicates that the rainbow population is now similar 

 to the 1959 level. As in Noxon Rapids, brown trout 

 and Dolly Varden have shown small increases. 

 Suckers, peamounth, squawfish, and yellow perch 

 are the principal non-game fish species. 



Brown trout and Dolly Varden are spawning suc- 

 cessfully in Cabinet Gorge. Small numbers of rain- 

 bow trout are also reproducing, but not enough to 



maintain a good fishable population. Only two tribu- 

 tary streams suitable for spavraing enter into Cabinet 

 Gorge. This lack of adequate spawning area is 

 thought to be one serious detriment to the establish- 

 ment of a self-sustaining rainbow trout population. 



Management of the two lower Clark Fork River 

 hydro-electric impoundments is now at a transitory 

 stage. Planting of large numbers of fingerling rain- 

 bow trout has produced good to excellent angling, 

 but only for a relatively short time. These hatchery 

 trout apparently have not established themselves as 

 a reproducing population and non-game fish have 

 increased in numbers to pre-impoundment levels. 

 Brown trout and Dolly Varden have fared well in 

 the two lakes, but whether these two species of fish 

 can maintain a desirable angler success level is 

 debatable. 



Population trend information has been collected 

 yearly from Hungry Horse Reservoir. This trend in- 

 formation shows that the peak reservoir population 

 was reached about 1958 and is now declining. This 

 decline is the result of many factors of which the 

 most important is the increasing age of the reservoir. 

 Numbers of Dolly Varden, whitefish, suckers, and 

 squawfish have remained constant, but the numbers 

 of cutthroat appear to have declined. 



Research was initiated during the biennium to 

 determine when and where the lake cutthroat and 

 Dolly Varden spawn, and the abundance of young 

 fish entering into the lake each year. Surveys were 

 started on tributary streams suitable for cutthroat 

 spawning. Work was started in conjunction with the 

 Forest Service to repair certain road culverts acting 

 as barriers to upstream movement of fish. The re- 

 moval of these culverts as barriers should increase 

 the area available to spawning cutthroat and Dolly 

 Varden considerably. 



Creel census information collected from Hungry 

 Horse Reservoir indicates that fishing success has 

 declined since the late I950's, but that it has leveled 

 off to a steady rate. The average size of the cutthroat 

 caught by anglers has increased from 0.5 pounds in 

 1958 to I.O pounds in 1961. Large Dolly Varden (5 to 

 15 pounds) are increasing in numbers in the annual 

 catch. In general, the Hungry Horse Reservoir is an 

 excellent "quality" fishery. 



30 



