144 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



Table 25. — Silver salmon run in the Columbia River, 1938 

 [Catch in number of fish, assuming an average weight of 10 pounds. Data combined and arranged by corresponding weeks] 



Note.— No catch was recorded for Zone 6. 



Table 26. — Chum salmon run in the Columbia River, 1938 

 ICatch in number of fish, assuming an average weight of 10 pounds. Data combined and arranged by corresponding weeks] 



For both silver and chum salmon it is quite apparent that such a small part of 

 each run goes above Bonneville that the same sort of analysis that was made of the 

 data for the other species would be meaningless for these. Obviously the chief 

 spawning areas are in the tributaries that enter the main river below Bonneville — an 

 inference that is in entire accord with the known facts of the distribution of these 

 species. Not only in the Columbia River but generally throughout their entire range, 

 both silver and chum salmon tend to spawn in the lower tributaries of the larger 

 rivers or in the shorter coastal streams. The same is true of the pink salmon, which 

 do not appear in the Columbia in commercial quantities. Under such circumstances 

 it is not possible even to approximate the number of fish in the entire run because the 

 sum of the fish taken below the dam and those counted past Bonneville do not form a 

 sufficiently large percentage of the whole, and without at least approximate informa- 

 tion as to the total number of fish in the run it is impossible to make the sort of 

 analysis that has been done with the chinooks, bluebacks and steelheads. 



The silver salmon first appeared in the river about the first of August, but the 

 catch did not amount to much until after the closed period from August 25 to Sep- 

 tember 10. On the other hand, a very large part of the total count past Bonneville 

 was made during the 2 or 3 weeks that were chiefly affected by the closed season. 

 (In table 25, the weeks ending August 20, August 27, and September 3.) Several 

 factors, alone or in combination, may account for these facts. First it appears that 

 a much larger percentage of the earlier fish than of the later ones pass above the dam 

 to spawn in the upper tributaries. Secondly, the intensity of fishing for this species 



