THE FISH BIOLOGY SECTION 



The Fish Biology Section is the technical branch of the Fishery 

 Division. Its function is to conduct experiments and gather informa- 

 tion on problems of and related to the sport fishery, and on the basis 

 of these findings, to develop and test new fish management measures. 



During the biennium, work has been in progress on thirteen dif- 

 ferent projects in addition to a variety of emergency or "trouble- 

 shooting" investigations. 



Stream Census Technique 



AGE AND GROWTH OF FISHES 



Through the examination of thousands of fish scales, tables show- 

 ing the average sizes of game fishes of Montana at various ages are 

 being constructed to provide a sound basis for evaluating growth of 

 fishes in individual waters and areas of the state. Complete or par- 

 tial evaluation has been made during the past biennium of fifteen 

 streams and twenty-one lakes in addition to numerous stock water 

 reservoirs. Studies made in south-central Montana have been used 

 by the management section in revising the hatchery-trout planting 

 programs for the Fromberg and Big Timber hatchery districts. 



The scale reading is done at the division's laboratory at the Mon- 

 tana State College where one permanent laboratory technician and 

 part-time student help are engaged. 



Studies are also in progress on the fluctuation in condition of 

 fishes. To aid in this study, alinement charts to facilitate calculating 

 condition factor, a figure that indicates robustness, were constructed 

 and a report^ published. 



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