Table 3. --Estimated percentages of whole eggs, egg fragments, and larvae in 



population, Sashin Creek study area 



Date 



Percentages of dead 

 whole eggs 



Mean 



Ninety -percent 



confidence 

 limits of mean 



Percentages of egg 

 fragments 



Mean 



Ninety -per cent 



confidence 

 limits of mean 



Percentages of dead 

 larvae 



Mean 



Ninety -per cent 



confidence 

 limits of nnean 



196Z 



March 20 



July 5 



August 1 3 



October 29 

 1963 



March 10 



1/ 



64 



34 



5 



25 



y 8 



+ 5 

 + 7 

 + 3 

 + 9 



+ 10 



20 

 53 

 95 



75 



92 



+ 3 

 + 9 

 + 3 

 + 9 



+ 10 



16 



13 















+5 

 +9 



i.' Whole eggs were mostly of the 1962 brood year. 





Wot 

 UJ o 



iij ** 



(r o 



Q-O 



n 



75 



""o FEB.I APR. I JUNE I AUG. I OCT. I NOV. I 



a. 



1962 



Figure 3. — Percentages of whole eggs, egg fragments, 

 and larvae in population of dead 1961 brood yeai 

 eggs and larvae in Sashin Creek study area. 



OBSERVATIONS ON 

 ENVIRONMENTAL FACTORS 



at temperatures near 1 and 2 C, and fry 

 emerged as temperatures were increasing 

 from 2° to 8 o c. Dead eggs of the 1961 brood 

 year were subjected to temperatures as high 

 as 16° C. in August 1962. 



Weekly mean temperatures for the period 

 October 1, 1961, through September 30, 1962, 

 are plotted and compared with the long-term 

 average weekly temperature for the same 

 months (records cover 11 years) in figure 4. 

 In 1961-62, autumn water temperatures tended 

 to be below, and winter, spring, and summer 

 water temperatures tended to be above the 

 11-year average. On the whole, water tem- 

 peratures in 1961-62 were above normal and 

 may have favored a higher than average decay 

 rate. 



Stream Temperature 



Pink salmon eggs are deposited in late 

 summer and early autumn as water temper- 

 atures decline; they hatch in autumn and early 

 winter as water temperatures approach their 

 lowest yearly levels; and fry emerge as water 

 temperatures begin to rise the spring follow- 

 ing egg deposition (Sheridan, 1962). Eggs of 

 1961 brood year Sashin Creek pink salmon 

 were deposited as temperatures were declin- 

 ing from 13° to 10° C. Most hatching occurred 



Stream Discharge 



Over the period of this study (October 1961 

 through March 1963) the discharge of Sashin 

 Creek ranged from 10 to 570 c.f.s. Over an 

 11-year period, 10 c.f.s. is the approximate 

 minimum flow recorded in wintei. The maxi- 

 mum discharge (recorded in autumn 1954) is 

 620 c.f.s. 



Considering again the period from October 

 1 tnrough September 30, we find that dis- 



