3.0 



2.5 



Q 



<2.0 



to 



3 

 O 



X 



I- 

 e> I K 



1.0 - 



O.OM ' ' ' 



Y = -I,238+73.5X 



'''■'''■■''■■■■''■'■ 



0.0 37.5 40.0 42.5 45.0 47.5 



MIDEYE-HYPURAL PLATE LENGTH (CM.) 



50.0 



Figure 11.— Relation of number of eggs to MEHP length for 52 pink salmon, early and late 



runs combined, Olsen Creek, 1963. 



reference to sockeye salmon from the Karliik 

 system on Kodiak Island, Alaska, noted that 

 both ovaries maintain the same rate of matura- 

 tion even though the number of eggs in each 

 ovary is different. Hartman and Conkle (1960) 

 found that about 90 percent of the left ovaries 

 contained more eggs than the right in sockeye 

 salmon from Brooks Lake, Alaska, in 1957 

 and 1958. Nelson (1959) reported that the right 

 ovary usually contained more eggs than the 

 left in sockeye salmon from Bare Lake, 

 Alaska. 



The number of eggs was recorded for the 

 right and left ovaries of 50 pink salmon from 

 Olsen Creek in 1963. The mean number of eggs 

 in the left ovaries was 954, and the mean for 

 the right ovaries was 978; the difference was 

 not significant. The left ovary contained more 

 eggs than the right in 21 fish (42 percent) and 

 fewer in 29 (58 percent). 



Egg Retention, 1962 and 1963 



Intermittently in 1962 and 1963 we examined 

 carcasses of spawned-out female pink salmon 

 to determine egg retention (the number of eggs 

 remaining in the carcass). The egg retention 

 at Olsen Creek in 1962 and 1963 was about 

 10 percent. During the late run in 1961 it 



reached 41 percent (Helle et al., 1964). The 

 high egg retention in 1961 was associated with 

 a high density of spawners. The retention was 

 only 7 percent in 1960, when the density of 

 spawners was similar to that observed in 

 1962 and 1963. 



SUMMARY 



Studies on the ecology of pink salmon in the 

 intertidal and fresh- water areas of Olsen Creek 

 began in 1960. Following is a summary of ob- 

 servations on the quality of the streambed 

 and the abundance, timing, distribution, length, 

 and fecundity of pink salmon in 1962 and 1963. 



1. The percentage of fines (materials pass- 

 ing through an 0.833-mm. sieve) in samples 

 of material from the streambed increased 

 from higher to lower tide levels. In streambed 

 materials taken in the upper intertidal area 

 before and after spawning, fines were sig- 

 nificantly lower in the postspawning sample. 

 Whether this difference was caused by spawn- 

 ing activity or flooding, or both was not 

 determined. 



2. The numbers of pink salmon spawning 

 in 1962 and 1963 were estimated by repetitive 

 stream surveys. The estimates by this method 



17 



