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FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



entire day; 6 pm. Saturday to 6 pra. Sunday. The effect of this accumulation was 

 to increase the catch during the following day or two, but it wore off until, by the 

 end of the week, little if any effect of the closed period remained. The character of 

 the cycle obviously has been determined by the combined influence of a Sunday 

 closed period and a very intensive fishery which, as shown above, takes approximately 

 80 percent of the fish entering the river during these 2 months. 



As an additional line of evidence of a dangerous intensity of fishing we have examin- 

 ed in some detail the daily catches and, for comparison, the daily count at Bonneville 

 Dam for the months of June and July, with attention to the variations in catch and 

 count within weeks; in other words, with respect to the variation that is associated 

 with the day of the week on which the catch or the count was made. The data are 

 presented in table 17, together with certain derived figures. From the figures of 

 catch and count given we have calculated for each week day, excluding Sunday in 

 dealing with catches, (1) the mean of the total deliveries for that day of the week 

 during the 8 weeks under investigation, (2) the mean percentage of the total catch 

 for the week, (3) the mean delivery per gill net, and (4) the mean percentage of the 

 weekly total count at Bonneville. These values are presented in table 18. It is 

 apparent that all three measures relating to the catch show much the same thing; 

 namely, that there is a fairly constant and uniform decrease during the first half of 

 the week, while the catch during the last half is relatively stable and at a much lower 

 level. On the other hand, no such progression is apparent in the count at Bonne- 

 ville. This is as one would expect in view of the fact that has just been demon- 

 strated — that the intensive fishery takes out of the run during the first 3 days of the 

 fishing week a very large part of the fish that have entered the river during the Sunday 

 closed period. 



Table 17. — Daily catch of chinook salmon in Zones 1 and 2, June 5 to July SO, 1938, and Bonneville 

 count for corresponding runs, June 19 lo August IS, with derived figures showing fluctuations in catch 

 during the week 



1 The ladders were closed this day because of manipulation of the water levels, 

 the count of the following day was divided equally between the two days. 



In calculating the percentage of the weekly total. 



