SALMON RUNS OF THE COLUMBIA RIVER IN 1938 



139 



Table 22 gives the data relative to steelhead trout in modified form. The catch 

 figures have been converted to number of fish on the basis of an average weight of 

 10 pounds throughout the season and in all zones. Tables 23 and 24 present some of 

 these data and certain derived figures for selected periods that have particular signific- 



I 5 - 



Figure 7.— Dominant elements in the 193S steelhead trout run, by weeks. 



ance. In preparing these tables and the graph (fig. 7) the same rate of travel has been 

 assumed as proved satisfactory for the study of the chinooks and bluebacks, and 

 the results appear to justify this assumption. 



From table 22 and figure 7 it is apparent that the steelhead run extends broadly 

 over the entire year, although the major part of the run comes during summer and early 

 fall months— from the middle of June to about the first of October. This major portion 

 shows 2 well marked modes, one at the week of July 9 and the other at the week of 



