Table 7. — Percentage of 0.1-m. "^ sanpling 

 units with more than three eggs of pink 

 salmon in three areas in Sashin Creek 



i E 



k i =1 



(live) ij 



^ (potential deposition) 



(1) 



■'■ Confidence limits were calculated from 

 normal approximation of the binomial distri- 

 bution. 



eggs than the finer materials in the middle 

 and lower areas. 



Survival of Embryos and Alevins 



The technique of randomly sampling 0.1- m.^ 

 areas of streambed provides an estimate of 

 survival from the time of spawning to the 

 time of sampling. Survival (S) is estimated 

 from number of live embryos and alevins 

 in spawning beds and potential egg deposi- 

 tion. An estimate of total survival for any 

 selected period is calculated from: 



where i_ designates an individual sampling 

 point (i_ = 1 to k) and j_ designates an indi- 

 vidual study area (j = 1 to 3). 



In calculating S., I assunned the number of 



eggs and alevins "collected at the i.th point to 

 be 93 percent of the total number present 

 at the time of sampling (McNeil, 1964b). 

 Potential egg deposition was calculated fronn 

 the estimated average nunnber of fennales 

 that spawned per square nneter, nnultiplied 

 by their average fecundity (1,900 eggs). 



Survival was estimated by use of equation 

 (1) in the three areas for the three periods: 

 (1) beginning to end of spawning (through 

 spawning), (2) beginning of spawning to end 

 of hatching (through hatching), and (3) be- 

 ginning of spawning to beginning of fry emer- 

 gence (to emergence) (table 8). Survival to 

 the end of spawning was estimated from 

 samples collected in late September; sur- 

 vival to hatching and survival to fry emergence 

 were estinnated from the samples collected in 

 late March. The nunnber hatching was esti- 

 nnated by sunnming live and dead alevins. 

 Dead alevins that disappeared before late 

 March would cause overestimation of sur- 

 vival through the hatching stage, but there 

 was evidence that the error from this source 

 was small. Average density of live-plus- 

 dead eggs and alevins in the middle and lower 

 areas did not change significantly between 

 late September and late March or in the 



Table 8. 



-Estimates of number and percentage survival of eggs and alevins from potential egg 

 deposition of 1963 brood year pink salmon in Sashin Creek 



