Table 1. — Dissolved oxygen content of intragravel water in Sashin Creek in the svimmers of 1962, 



1963, and 1965^ 



^ No samples were collected in the summer of 1964. 



high. Repeated measurements of the tempera- 

 ture of the intragravel water in the three seg- 

 ments consistently failed to reveal statistically 

 significant differences in the mean values. 

 Thus, we presumed that any differences in 

 growth and development of embryos and alevins 

 that we might observe would result from factors 

 other than water temperature. 



GROWTH AND DEVELOPMENT OF 

 EMBRYOS AND ALEVINS 



In Sashin Creek, pink salmon spawn in 

 August and September; the eggs hatch in 

 Novennber and December; the alevins remain 

 in the streambed during winter; and the fry 

 emerge and migrate to sea in April and May. 



The present study pertains to eggs and 

 alevins of the 1961, 1963, and 1965 brood years. 

 Because pink salnnon live only 2 years from 

 fertilization of the egg to maturity and death 

 of the adults, the odd- and even-numbered 

 brood years are genetically separate. It is 

 not unusual in populations of pink salmon for 

 one of the two lines to be n-iuch more abundant 

 than the other. Over the period of this study, 

 the odd-year line was dominant in Sashin Creek. 

 In fact, fish were too scarce in the even-year 

 line to permit comparisons of the growth and 

 development of eggs and alevins sinnilar to 

 those we made for the odd-year lines. 



Eggs and alevins were collected from random 

 points on the spawning ground with the aid of 

 a hydraulic sampler (McNeil, 1964), and the 

 samples were preserved inStockard's solution 

 (six parts Formalin, five parts glycerine, four 

 parts acetic acid, and 85 parts water). 



1961 and 1963 Brood Years 



The studies of the 1961 and 1963 brood years 

 were prelinninary and concerned alevins col- 

 lected in March shortly before fry began to 

 leave the gravel; the alevins were weighed only. 

 They were taken from the Stockard's solution 

 and blotted with paper towels to ren-iove exces- 

 sive nnoisture. The first indication of possible 

 differences in the average weight of alevins 

 from the three segnnents of the Sashin Creek 

 spawning ground came in March 1962 (1961 

 brood year); the alevins from the upper segment 

 were significantly heavier (P>0.05) than those 

 from the middle and lower segments. The same 

 relation held in March 1964 (1963 broodyear). 



The average wieghts for the two broodyears 

 were as follows: 



1963 



Streann segnnent 



1961 



