40 



BULLETIN OF THE BUREAU OF FISHERIES 



of that year was disproportionately heavy, as compared with the commercial catch, 

 or whether the natural conditions were unusually favorable for the 1912 brood, with 

 the mortality factor greatly reduced, is a question concerning which we have no 

 information for this year. Whether such lack of correlation as frequently exists 

 between commerical catches of the corresponding years of successive cycles is due 

 to discrepancies between the commercial catches and the spawning escapements, or 

 to the disturbing influence of the variable natural factors (aside from spawning 

 intensity) that control abundance, is the principal problem we hope to solve by 

 means of the present series of experiments. 



Table 6. — Random samples of the Karluk red-salmon run of 1917, distributed by age groups, sex, and 



length 



[M=male; F=female] 



Length, in 

 inches 



Age groups and sex 



Total 



81 



3j 



4i 



4i 



5 8 



5 3 



5) 



63 



64 



7< 



M 



F 



M 



M 



F 



M 



F 



M 



F 



1 



M 



F 



M 



M 



I 



1 



M 



F 



M 



16 







1 



















































1 















19^2 









































































20H 























1 



2 

 2 

 9 

 11 

 38 

 51 

 69 

 64 

 63 

 15 

 4 

















21 — 





































21K2 - 





















2 

 3 

 3 

 17 

 16 

 26 

 32 

 58 

 54 

 57 

 21 

 8 

 2 











1 







22-- - 





















1 









1 

 2 

 4 

 3 

 7 

 6 

 6 

 4 

 1 







22^ 

































23 — 



1 



1 





1 







1 





1 





1 





1 

 1 

 7 

 4 

 6 

 2 

 4 









23H 





1 















24 - 











1 







1 

 1 







3 

 3 

 4 



12 

 10 

 3 

 2 







24H - 















1 











25 









1 

















25K 















1 

 1 







5 

 3 

 2 

 2 

 2 







26 

























26H 



























27 





























1 





«H 

















1 















Total.. 

































1 



1 



1 



2 



1 



1 



1 



4 



3 



299 



329 



2 



15 



25 



37 



35 



1 



758 



RUNS OF 1919 AND 1921 



For the year 1919 we have but a single sample, obtained on July 26 and consist- 

 ing of 103 individuals. This doubtless gives reliable indication of the constitution of 

 the run on that date but takes no account of the changing elements of the run as these 

 appear during the course of the season. In Table 7 we enumerate the individuals in 

 our sample and refer them to their appropriate age groups, sex, and length groupings. 

 From this it appears that the 5 3 group continues to be dominant, constituting 81 per 

 cent of the sample, but represents a somewhat smaller proportion of the run than in 

 any other year we have considered. The pack of red salmon in 1919 was small, 

 amounting to only 78,000 cases, and it is of interest to ascertain that the principal 

 element present in the run was derived from the year 1914, which furnished the 

 smallest pack known in the history of the river (39,000 cases). 



