The importance of environment to maximum production has 

 ah-eady been demonstrated. During the 1949 season, an average of 

 13.5 pounds of trout per 150 feet of stream was removed with the 

 electric shocker from sections with one or more medium sized pools. 

 On the other hand, only an average of 3.4 pounds of trout per 150 

 feet of stream was resident in those sections with 100 per cent riffles 

 or small pools and riffles. Approximately three-quarters of this 

 stream is in the low production category. Experiments are underway 

 to determine the feasibility of increasing production by artificial 

 stream improvement. 



COOPERATIVE PROJECTS 



The Fish Biology Section has profited by cooperative relations 

 with the Montana State University, the Montana State College, and 

 other organizations in the state concerned with fisheries work. The 

 Montana State College has furnished this department office and lab- 

 oratory space, has granted the department staff access to libraries and 

 biological collections, has granted loans of specialized equipment, and 

 has made its staff members available for consultation on biological, 

 chemical, and mathematical problems. We gratefully acknowledge 

 these benefits. 



ROUGH FISH CONTROL 



The policy of the State of Montana is to manage their waters 

 for sport fishing, however, on several occasions an attempt has been 

 made to control the rough fish populations in some waters. During 

 the biennium, rough fish work in the Clearwater Lakes area and the 

 Thompson Falls, Clarks Fork area were pointed toward the cutting 

 down of the population of suckers and squawfish. By installing 

 traps where the suckers and squawfish migrate, many tons have 

 been taken and the resulting fish were utilized as fish food at the 

 Anaconda and Arlee hatcheries. The past season, temperatures were 

 taken at the racks to determine at what temperature the suckers and 

 squawfish move. This will enable the department to know when to 

 install the traps and put them in operation to catch the peak run of 

 the rough fish. Several lakes were seined in an endeavor to curtail 

 the sucker population and make more room and better habitat for 

 the game fish. 



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