The effects of river flow and temperature upon the time of run 

 were evaluated by a multiple-regression analysis using the figures shown 

 in parentheses in table 2. The following subscripts were used in express- 

 ing the results; R = time of run, F ::: time of low river flowy and T = 

 time of high temperature o A value of Rr,tF = Oo70 was obtained, which is 

 significant at the 5-percent level. A value of R^ = OoU9 was obtained, 

 showing that approximately half of the variation in time of arrival of 

 run at Bonneville can be attributed to the variation in flow and tempera- 

 ture (Snedecorj I9I46) . 



A linear-regression analysis showed that there was a sifinifi- 

 cant correlation at the 5-percent level between flow and time of run, 

 (■""RF = 0.666), The correlation coefficient for temperature and time was 

 not quite significant at the 5-percent level (rj^ ■j _ 0.5U)« Similarly, 

 the correlation coefficient for flow and temperature was not quite signifi- 

 cant at the 5-percent level (rp-j _ 0.5^5) . A value of D.553 for both of 

 these correlations is necessary for significance at the 5-percent level 

 (Snedecor, I9U6) , 



It was desired t-o know whether the factors influencing the time 

 of run at Bonneville also affected the time the shad were in the river 

 below Bonneville , Statistics of the monthly landings for each year from 

 1938 through 19h9 were available from the Oregon Fish Commission (1950) . 

 Preliminary figures for 1950 were obtained from the Oregon Fish Commission 

 and the Washington Department of Fisheries, Catches of shad in the 

 Columbia River were recorded as early as February, but the first month 

 that they were caught in numbers was May. The percentage of shad caught 

 up to and through the month of May each year was calculated, and this was 

 used as an index of the time the shad runs arrived in numbers in the river. 

 The percentages are as follows: 



Percentage caught 

 Year through May 



1938 3ii 



1939 52 

 19I4O 56 

 19hl la 

 19U2 30 

 19U3 21 

 19hi; 22 

 19h5 19 

 I9U6 21 

 19U7 28 

 19h8 19 

 191^9 21 

 1950 12 



13 



