40 



30 



: 20 



10 



10-YEAR 

 AVERAGE 



I - 10 11-20 21-31 1-10 11-20 21-30 1-10 11-20 21-31 

 JULY AUGUST SEPTEMBER 



Figure 2. — Total rainfall at Sashin Creek by 10- and 11- 

 day periods in July, August, and September — average 

 for 10 years, 1957-66, and for 1966. 



Dissolved Oxygen in Intragravel Water 



I determined the concentration of dissolved 

 oxygen in intragravel water of the Sashin Creek 

 spawning grounds on August 21, shortly before 



the pink salmon began to spawn, and on 

 September 9, near the midpoint of spawn- 

 ing. The dissolved oxygen in intragravel water 

 is replenished by downwelling stream water-- 

 the amount of downwelling in general increases 

 as the streamflow increases (Vaux, 1968), 

 and the amount of dissolved oxygen in the 

 intragravel water increases as the stream- 

 flow increases (McNeil, 1962). The amount 

 of intragravel oxygen is in general directly 

 proportional to streamflow. The average con- 

 centration of oxygen in intragravel water 

 was 6 mg./l. or greater (always more than 

 50 percent of saturation) in the three sections 

 on both sampling dates (table 3). I believe 

 these values are representative of conditions 

 through the spawning period because they were 

 taken at intermediate flows. 



NUMBER, TIME OF MIGRATION, 



DISTRIBUTION, AND FECUNDITY 



OF SPAWNERS 



The adult pink salmon that returned to 

 Sashin Creek in 1966 were counted and sampled 

 as they passed through a weir at the head 

 of tidewater and again during surveys of the 

 spawning grounds. These fish are assumed to 

 be mostly progeny of the stock transplanted 

 to Sashin Creek in 1964. 



The methods and procedures used were those 

 that have become routine for studies of pink 

 salmon in Sashin Creek; most have been de- 

 scribed in detail by McNeil (1964, 1966). 

 Males and females were counted daily at 



Table 3. --Dissolved oxygen content of intragravel water in Sashin Creek on August 21, 

 before spawning, and September 9, midpoint of spawning, 1966 1 



Middle 



Aug. 21. 

 Sept. 9. 



Lower 



Aug. 21. 

 Sept. 9. 



11.4 

 9.5 



11.4 

 9.5 



30 

 26 



30 

 24 



6.0 

 8.2 



6.0 

 8.4 



+0.6 

 +0.7 



+0.7 

 +0.5 



53 



71 



53 



73 



1 Methods of sampling were described by McNeil (1962). 



