study is essentially complete, but final analysis 

 of the data is still in progress. Observations 

 on the forest spraying program will be con- 

 tinued, but will be carried as projects in the 

 individual fishery districts directly concerned. 



Fisheries Investigation Laboratory 



During the biennium this project included 

 studies on age and growth of fish, food habits 

 of fish and analyses of samples of stream bot- 

 tom insects. These jobs were done for fish 

 managers and biologists on a statewide basis. 

 Location of the laboratory on the Montana 

 State College campus allows the use of part- 

 time student help to do much of the time- 

 consuming sorting and preparations. 



Age and growth data are used extensively 

 in forming management plans. During this 

 period over 8,600 scale samples from fish were 

 processed. These data were returned to the 

 fisheries project leaders throughout the state. 

 Age and growth data for rainbow, cutthroat, 

 brown, and brook trout from 51 streams and 

 37 lakes were tabulated and ranked according 

 to growth rates as a part of an investigation 

 to determine if total dissolved solids of the 

 waters can be used as an aid in classification 

 of Montana's waters into broad productivity 

 types. 



Stream bottom insects provide much of 

 the trout food and serve as indicators of losses 

 to stream production through pollution. In all. 

 101 bottom samples from Sheep Creek, Deep 

 Creek and the Boulder River and 205 drift 

 ample from the Bitterroot drainage were 

 sorted and classified mainly in studies to check 

 on the effects of spraying spruce budworm 

 v ill i DDT. 



About 500 fish stomachs, from ij >. cimen 

 taken in Flinl Creek and the Clark Fork River, 

 ed to detei mine the food habits 



i : i] fi he 



In addition to these jobs the laboratory 

 pei onnel provided Liaison with variou 

 pai tm< ni "i Montana state College as well 



as supp] ing cl a] pre lervatives and sup 



plii to field i" ' onnel. 



States i « I « - < Ireel < iensus 



\ h;ii kinds of H ih 

 and i ught? The succe 



of Montana's quarter million fishermen is of 

 utmost importance to the Montana Fish and 

 Game Department. This information is ob- 

 tained by creel census. Statewide creel census 

 has been in operation since 1948. Catch in- 

 formation is gathered by wardens, biologists 

 and hatcherymen. and is received from sports- 

 men in Fisherman's Logs and through ques- 

 tionnaires sent to a 10'. sample of fishing 

 license holders. This information is tabulated 

 by electronic machines. It is used by the 

 district fisheries managers in managing the 

 state's waters. 



More than 60' ! of the fishermen in Mon- 

 tana prefer trout stream fishing to any other 

 type of fishing. Residents fished most in the 

 Flathead River drainage while most non-resi- 

 dents prefer the Madison River drainage. Ang- 

 lers average catch was 4.5 trout and salmon 

 for each day spent fishing. Montana rates with 

 the top trout fishing states if. indeed, it is 

 not the top state. 



Reservoir Investigations 



Hydro-electric plants have been built on 

 many of the larger rivers of Western Montana 

 during recent years. The reservoirs created 

 by these projects have provided improved con- 

 ditions for rough fish which have increased 

 rapidly during early years of impoundment. 

 Introductions of fingerling trout have provided 

 good fishing in most reservoirs during early 

 years but as the rough fish become more 

 abundant survival and harvest of game fish 

 declines rapidly. Continued management of 

 reservoirs requires the use of larger hatchery 

 fish and costs soon become prohibitive, 



Verj little information is available regard- 

 ing the ecology of these large reservoirs 

 construction of a hydro electric plant at Noxon 

 Rapid on the I Hark Foi k River near Noxon, 

 Montana offered an opportunity to gel detailed 

 information regarding the changes that occur 

 m such waters during the early years of Im 

 poundmenl tl also afforded an opportunity 

 to invesl igate management techniques that 

 might be applied to these large bodi< 

 water. During this biennium a long range 

 itudj w •' tai ted on Noxon and other 1 1 



The proje< I is financed 

 i with fundi made available bj the 

 Wai hington Water Power Compart} . the a 





