Of the total, 9,610, or 59 percent, were 

 females, thus confirming the hypothesis of 

 downstream displacement of spawned-out 

 males. Therefore, carcass counts at the weirs 

 were combined with carcass counts in the 

 upstream areas for a more accurate repre- 

 sentation of the true sex ratio. Of the 25,892 

 total carcasses thus obtained, 13,117, or 51 

 percent, were female. Again, a study of 

 seasonal change in sex ratios indicated two 

 distinct runs of pink salmon in 1961. 



Weir live fish counts, 1961 . --Adult salmon 

 were tallied by sex in 1 96 1 as they migrated 

 upstream through the weir gates. Sex was 

 deternnined from secondary sexual char- 

 acteristics observed from overhead as the 

 fish swam over a light-colored contrasting 

 bottom. Of the 35,758 pink salmon tallied in 

 this manner, 18,396, or 51 percent, were 

 females (table 6). Two consecutive peaks in 

 relative abundance of females were indicative 

 of two discrete runs into the upstream areas 

 (fig, 19). No important differences were ob- 

 served in total numbers, timing, or sex ratios 

 in the two forks, 



Intertidal carcass counts, 1961 . --Carcasses 

 tallied by sex in the intertidal areas in 1961 

 totaled 37,185 of which 19,563, or 53 percent, 

 were females (table 6). In contrast to the 1960 

 intertidal counts when s,ex ratios indicated only 

 a single spawning stock for the season, there 

 was a progression through two distinct periods 

 of maximum relative abundance of females 

 (fig. 18). These coincided in time with sinnilar 

 maxima observed for dead fish at the weirs 

 and upstream areas. Therefore, both the early 

 rvm and the late run utilized intertidal as well 

 as upstream spawning grounds in 1961. 



FECUNDITY 



Fifty female pink salmon were collected 

 during the 1960 spawning season and 100 

 during the 1961 season to determine fecundity 

 of Olsen Bay fish. The 1960 samples were 

 collected a few at a time by seining at 4-day 

 intervals along the beach area near the streann 

 mouth from July 31 to August 14. In 1961, 

 100 females were taken in two collections of 50 

 fish each. The first 50 fish were taken be- 

 tween July 5 and 8 with a dip net from areas 

 immediately below the East and West Fork 

 weirs. The second 50 fish were taken between 

 August 17 and 19 in the sanne nnanner from 

 below the West Fork weir. Ovaries were re- 

 nnoved from each fish and boiled for at least 

 10 minutes until eggs were separated from 

 skeins. The eggs were preserved in 10-per- 

 cent formalin. Before being counted they were 

 placed in sieves and rinsed in water to remove 

 formalin. Total counts were made for all 

 ovaries, using egg counting boards (fig, 20). 



Egg Covints in Relation to Size, 1960 



The 1960 females ranged from 38.4 to 47.5 

 cm, long (average, 43,0 cm,) and contained 



Figure 19. — Percentage of females among pink salmon 

 moving upstream through the weirs, Olsen Bay, 1961, 



Figure 20. — Board used for making total counts of eggs 

 from ovaries of pink salmon, Olsen Creek, 1960-61. 



19 



