Table 7. — Average length and fecundity of female pink salmon, Sashin Creek, 



1959-66 



Year 



Females 

 in sample 



Fecundity 



90-percent 

 confidence limit 



Number 



Cm. 



Number 



1959.. 

 I960., 

 1961.. 

 1962 1 . 

 1963.. 

 1964 . . 

 1965 . . 

 1966.. 



Number 



+51 

 +58 

 +55 



+110 



+67 



+130 



+135 



No females were measured because total run was only eight fish. 



data on length (mideye to fork of tail) and 

 fecundity from 1959 to 1966. The length and 

 fecundity of the stock transplanted in 1964 

 and of their progeny of 1966 are within the 

 range of values observed in the native stock 

 since 1959. 



Efficiency of Egg Deposition 



Efficiency of deposition--the success of 

 female pink salmon in burying their eggs 

 in the gravel--is the percentage of the potential 

 egg deposition for the entire escapement es- 

 timated to be in the gravel at the end of 

 spawning. This figure can be calculated for 

 Sashin Creek as a whole from data collected 

 with hydraulic sampling gear (McNeil, 1964). 

 The values for each year from 1963 to 1966 

 are 53, 56, 82, and 37 percent, respectively. 

 The efficiency of deposition was somewhat 

 lower in 1966 than in the previous 3 years; 

 I attributed this lower efficiency to the rela- 

 tively high, though not flooding, water levels 

 throughout most of the spawning period. Con- 

 versely, the high efficiency of deposition in 

 1965 was attributed to low flow (McNeil, 

 1968). In the 37-day period August 20 to 

 September 25, the average daily streamflow 

 exceeded 0.7 c.m.s. (about five times the 

 base flow) on only 5 days in 1965, whereas 

 it exceeded this value on 30 days in 1966 

 (fig. 3). 



Differences in efficiency of egg deposition 

 associated with differences in streamflow 

 may be a major cause of the positive cor- 

 relation described by McNeil (1968) between 

 early stream entry and high total fresh- 

 water survival over the wide range in abun- 

 dance of spawners in Sashin Creek. The 

 data for Sashin Creek show an inverse relation 

 between rainfall (and streamflow) and earli- 



i i i i ' l ' ' ' > I 



25 30 I 4 



AUGUST 



I I I I | I I I I | I 

 14 19 24 



SEPTEMBER 



Figure 3. — Daily average streamflow, Sashin Creek, 

 August 20 to September 25, 1965 and 1966. (Data modi- 

 fied from U.S. Geological Survey, 1967.) 



ness of season--i.e., July and August have 

 relatively little rainfall (fig. 2) and low stream- 

 flows, whereas September has relatively heavy 

 rainfall and high streamflow. Wickett (1958) 

 demonstrated a positive correlation between 

 the amount of rainfall or stream discharge 

 and survival of a stock (to returning adults) 

 in British Columbia. He concluded that sur- 

 vival of eggs in the gravel appears to be im- 

 proved by favorable discharge during early 

 incubation. 



