Table 12. — Catch by mesh size and catch ratio of adjacent 

 mesh sizes, chum salmon, 1967 



26 



32 



38 44 50 56 



FORK LENGTH (CM.) 



7. — Catch ratio of adjacent mesh sizes by fork 

 length, chum salmon, 1957. 



26 



38 44 50 56 



FORK LENGTH (CM.) 



Figure 8. — Catch ratios of adjacent mesh sizes by fork 

 length, chum salmon, 1959. 



had spent mainly two and three winters at sea. 

 Mode 1 did not change position, but mode 2 

 shifted to smaller fish when adjusted for selec- 

 tivity. This change occurred in both years. 



Chum salmon 



The problems encountered for chum salmon and 

 the results obtained are almost identical to those 

 for sockeye salmon. As with sockeye, chum 

 salmon catch ratios of a minimum 50-fish sample 



' Original catches of the 4^-inch mesh were 3 times as large as shown; they 

 were divided by 3 to equalize fishing effort between mesh sizes. 



Note. — Catch ratios in parentheses were not used. See text. 



Table 13. 



-Catch by mesh size and catch ratio of adjacent 

 mesh size, chum salmon, 1969 



' Original catches of the 4W-inch mesh were 6 times as large as shown; they 

 were divided by 6 to equalize Ashing effort between mesh sizes. 



Note. — Catch ratios in parentheses were not used. See text. 



for each pair of mesh sizes were approximately 

 linear over a greater part of the range of fish 

 lengths but not at the extremes. The length 

 ranges for chum salmon were identical to those 

 established for sockeye. Least squares lines were 

 fitted to the 1957 and 1959 catch ratios of the 

 three pairs of mesh sizes (figs. 7 and 8). Catches 

 on which these lines were based are given in tables 

 12 and 13. Table 14 sums up the ordinate heights 

 for the four mesh sizes. 



Figure 9 and table 15 show the uncorrected and 

 corrected length-frequency distributions of chum 



GILL NET MESH NET SELECTION CURVES FOR SALMON 



387 



