Table 6 Seasonal changes in percentage of females among pink salmon adults at Olsen Bay in 



1960 and 1961^ 



[Total numbers of adults in paiendieies] 



•"■ Weekly periods start on July 1. 



indicative of a single run or stock with no 

 evidence of early and late races. There was 

 a steady increase in relative abundance of 

 females fronn a mininnum of 33 percent, 

 July 17-23, to a maximum of 64 percent, 

 September 11-17. 



Weir carcass counts, 1961 . --In 1961, 9,507 

 pink salmon carcasses were counted at the 

 weirs, and 3,507 specimens, or 37 percent, 

 were females (table 6), As in the previous 

 years the excess of nnale carcasses at the 

 weirs was not indicative of true sex ratios 

 in the upstream areas. During the 10-week 

 period from July 9 through September 16, 



fennales were in the minority in two cycles, 

 followed by a gradual progression until females 

 were predominant. Thus, early and late runs 

 of pink salmon were clearly indicated by 

 seasonal changes in sex ratio in 1961, 



Upstream carcass counts, 1961 . --Also in 

 1961, upstream dead fish were tallied by sex 

 to determine whether fennales stayed close to 

 their redds till death, while dying males 

 drifted downstream to the weirs. Dead pink 

 salmon totaled 16,385 in the upstream areas 

 (table 6) with no important differences in total 

 nunnbers or sex ratios between the two forks. 



18 



