Further studies would be needed to determine 

 whether the dead eggs were removed by shift- 

 ing gravel or by predation in the 3- to 4-foot 

 stratun-i and to determine whether sonne fry 

 emerged prior to sampling because of higher 

 water temperatures at that tide level. 



The 35 fry per square foot at the 7- to 

 9-foot stratum and the 73 per square foot at 

 the 10- to 11 -foot stratunn represent 20 and 

 54 percent respectively of the mean live egg 

 densities in those areas the previous fall. 



SUMMARY 



1. A field research station was established 

 at Olsen Bay in Prince William Sound in 1960 

 to compare life history, ecology, and survival 

 of pink salmon in intertidal and fresh-water 

 spawning areas. 



2. Olsen Creek is subject to rapid fluctua- 

 tions in flow, depending on amount of rainfall. 

 Discharge during summer months ranged from 

 10 to about 500 c.f.s. (average, about 33) for 

 each fork. 



3. Mean tide range at Olsen Bay is 10 feet, 

 and diurnal range is 12.3 feet. The stream is 

 covered with tide water more than 80 percent 

 of the time at the 3-foot tide level and about 

 3 percent at the 12-foot level. 



4. Preliminary investigations of salt-water 

 intrusion into the intertidal area of the creek 

 demonstrated that saline water penetrates the 

 gravel at redd depth. The highest concentra- 

 tion at the 11-foot tide level was 9.3°/oo dur- 

 ing a 14.5-foot tide. 



5. Temperatures of gravel water, 8 to 10 

 inches below the stream bottom, were deter- 

 mined at each foot of elevation between the 

 3- and 10-foot tide levels. Elevations up to the 

 8-foot level were subject to temperature varia- 

 tions as large as 10° F. within 1-hour periods. 



6. Preliminary studies on gravel composi- 

 tion showed an increase in fine materials and 

 a decrease in large gravel from high to low 

 tide levels. 



7. Random sannples of intertidal inhabitants 

 indicated that a greater number of species 

 existed in the tideflat between streams than 

 in the streams themselves. Large numbers of 

 microdrile oligochaetes were found in stream 

 gravels. 



8. Occurrence of spawners in even- and odd- 

 year cycles (1960 and 1961) was bimodal. 

 The early run in 1960 utilized both intertidal 

 and fresh-water areas; however, the late run 

 was entirely intertidal. In 1961, both runs were 

 divided between intertidal and fresh-water 

 areas. 



9. In 1960, 98,574 pink salmon spawned in 

 Olsen Creek and in 1961, 135,905 spawned. 

 During both years 74 percent of the total run 

 spawned in the intertidal portionof the stream. 



10. The period of time that spawners lived 

 after entering the streann ranged from 21 days 

 at the beginning of the season to 5 days at the 

 end. Average duration of stream life for the 

 entire season was 11.1 days. 



11. In 1960, mean length of late females 

 was significantly smaller than the mean for 

 early females. In 1961, seasonal differences 

 were more obvious, and late spawning males 

 were significantly larger than early males and 

 late females were significantly larger than 

 early females. Pink salmon that spawned in 

 the small intertidal creeks. Middle Slough and 

 Little Creek, in 1960 were significantly smaller 

 than spawners in the main stream. 



12. Seasonal changes in sex ratios verified 

 the presence of two distinct spawning groups 

 of pink salmon in 1961 but not in 1960. 



13. Average number of eggs per female in 

 1960 was 1,815. Regression analysis indicated 

 no relation between length and number of eggs 

 per female. In 1961, both the early and late 

 runs were sampled for fecundity. Average 

 number of eggs per female was 2,092 for the 

 early run and 2,096 for the late run. Regres- 

 sion analysis showed that length and number 

 of eggs were related for the early run but not 

 for the late run. 



14. In 1960, mortality due to egg retention 

 was approximately 7 percent. In 1961, egg 

 retention ranged from 2.7 to 41.5 percent. 



15. Overwinter survival between egg and 

 fry stages was below the 4-foot level, 20 

 percent in the 7- to 9-foot level, and 54 per- 

 cent in the 10- to 11 -foot level. 



ACKNOWLEDGMENTS 



The authors wish to acknowledge the 

 contributions of the following individuals: 

 Fredrik V. Thorsteinson and Theodore R. 

 Merrell, Jr., for the initial planning and 

 organization of the study of intertidal spawning 

 at Olsen Bay and for their continued guidance, 

 and Loyal Bouchard, Jerry Hout, James Kirk- 

 wood, and Robert Yancey for their participa- 

 tion in the planning and field work. 



This paper is dedicated to the memory of 

 the late Charles Y. Conkle who for his valuable 

 contributions to the planning and field work 

 while under the stress of a debilitating ill- 

 ness, earned the respect and admiration of 

 his coworkers. 



UTERATURE CITED 



ANAS, RAYMOND E. 



1959. Three-year-old pink salmon. Journal 

 of the Fisheries Research Board of 

 Canada, vol. 16, no. 1, p. 91-94. 



23 



