FISHERY BULLETIN: VOL. 71. NO. 3 



Table 3. — Salmon catches by time periods. 1 June to 2 .Tuly 1965. 



6/15 52°55' 



6/22 55°50' 



7/2 56°24' 



MV Puraf^on: 

 6/1 53°43' 



6/7 



53°20' 



7/2 



56°17' 



167°43' 

 164° 00' 



6/25 57°0r 159°58' 



162°00' 

 160°44' 

 165°52' 



162°00' 



Time 

 period 



(see Fig. 2) 



Catch 



1st 3-h 

 unit (c'l) 



6-h 



unit (C) 



8 

 2 

 49 

 18 

 13 

 14 

 18 

 38 

 38 

 22 

 100 

 73 

 36 

 18 

 22 

 17 

 3 

 25 

 35 

 67 

 44 

 30 



3 



7 



7 



167 



19 



170 



5 



3 



4 



67 



53 



40 



37 



9 



61 



23 



14 



3 



44 



166 



31 



89 



7 



3 



15 



1 



8 



6 



8 



18 



2d 3-h 

 unit (c-2) 



Total 



52 



1,778 



2,109 



1,467 



sion analysis. Secondly, since the measure of 

 dropout refers to the fish which enter the 6-h 

 unit during the first 3-h period and disappear 

 during the second 3-h period, it seems reason- 

 able to weight more heavily those points in 

 which large numbers of fish entered during the 

 first 3-h period. 



The resulting weighted regression line is 



shown in Figure 5. In spite of the apparent wide 

 scattering of points, the relation is significant 

 at the 5% level (t = 8.48). The estimate of loss 

 of salmon from the gill nets is 27% for the 3-h 

 period ; the 80% confidence interval is from 5 to 

 48%. 



In the model used in estimating dropouts 

 during a 3-h interval, we have assumed that 



852 



