The dam counts and total runs analysis is illustrated in figure i;, in 

 which :°t can be seen that since the low of IS'U^j the runs have shown sigTis 

 of recovery. Since bluebacks ai-e predominantly i; years old at time of re- 

 turn, the counts in figure !? are plctv-ed by U-year cycles. Of particular 

 interest is the marked increase of bluebacks passing Rock Island Dam. The 

 count there probably represents the best measure of the spawning escapement, 

 because no commercial fishery takes place beyond it, and because there is no 

 eAH-dence that the fish unaccounted for between Bonneville Dam and Rock Island 

 Dam spawn successfullyo 



SPAMING SURVEYS 



The 19li7 blueback run was an exceptionally large oneo The commercial 

 catch totaled 7013383 pounds or 219jl82 fish (bashed on average weights 

 taken in Astoria, Oregon, by F, G, Bryant, 19li7^' ) , and the total run was 

 3385 3U8 fish for the year^, the largest since I926, 



The original purpose of the surveys reported on herein was to determine 

 how the record 19ii7 run and future runs of perhaps larger magnitude would 

 fare on the remaining spawning grounds » In short, would the spavming gravels 

 be overpopulated to the point where it would have a deleterious effect on the 

 survival of the eggs? 



The surveys were made during the spawning seasons of 19^7 .t 19ii8j 19^9^ 

 and 19^1., The spawning nopulations were enumerated during the surveys by 

 means of boat and motor, rubber raft, or by footj, depending on the condition 

 of the various streams, l'\fhen too shallow or too swift, the stream was sur- 

 veyed on foot. When conditions permitted, a rubber boat was used^ or when the 

 stream was deep enough the motor and boat were used. There were three pos- 

 sible types of counts f (1) Live fish, (2) redds or spawning nests, and (3) 

 dead fish. Only the first of these was used, since it was impossible to 

 distinguish individual redds where they were in close proximity, and since 

 dead fish tended to settle in deep pools and disappear from sight. Individ- 

 ual fish were counted whenever possible, but on crowded spawning gravels 

 they were occasionally estimated by tens» 



THE LAKE WENATCHEE SURVEYS 



The first surveys were begun in the Lake Wenatchee region, where spaivn- 

 ing occurs earlier than in the Okanogan area. Figure 6 is a diagrammatic 

 map of the Vfenatchee system showing where the major portion of spawning takes 

 place. The main spawning areas are in the lower 2 miles of the North Fork of 

 the White River and the main stem of the Wliite River from the North Fork down- 

 stream to within 2 miles of Lake Wenatchee, Blueback spawn in the Little 



^ "Average Weights of Columbia River Salmon", T^TtT Floyd G, Bryant, 

 unpublished report. 



