32 



Within a single stream, Rocky Creek near Bozeman, there was variation 

 from 25 kg/km in a straightened section in springtime to 222 kg/km in an 

 unaltered section in autumn. In Bozeman Creek, where we have data from 8 

 sections (encompassing 18 shortered stations), trout abundance ranged from 

 42 kg/ km in one urban section and in one natural section far upstream to 

 155 kg/km in a relatively unaltered section (station 36) which, however, 

 may have been influenced by nutrients from a mink farm. 



Trout biomass abundance of natural stream sections was inversely related 

 to channel steepness (Table 8, Figure 6). From the plot of trout abundance 

 against channel gradient in Figure 6, it is evident that urban or straightened 

 sections held less trout than natural stream sections of equivalent gradient. 

 The estimates of stream gradient must be regarded as rather rough. Within 

 the apparent gradient-trout relationship, sections of Bozeman Creek having 

 highest abundance of trout compared favorably with abundances in other 

 streams that had natural channels . 

 Further Analysis Planned 



Further refinement and augmentation of various aspects of the data 

 analysis in this study are warranted. Confidence limits on estimates of 

 biomass remain to be calculated, as well as improvements in computations 

 involving grouped data for contiguous stations (stream sections). HQI 

 analysis and multiple-correlation analysis of data from the 30 stations 

 should be repeated using stream section data instead. Comparisons of 

 means should be further analysed with weighting of data according to 

 stream station or section length. 



Most aspects of trout population size structure and age-growth analyses 

 remain to be performed. Scale samples were taken from most fish captured 



