floods in 1960 and 1961 and unknown numbers 

 of fish passed upstream without being counted 

 (Helle et al., 1964). 



The estimate of the intertidal spawning popu- 

 lation by the peak count nnethod in I960 was 

 less than the estimate by the foot survey method 

 (table 3). This peak count estimate would be 

 low because freshets, tidal action, and bears 

 probably removed many of the carcasses before 

 they could be counted. 



Table 3. — Number of spawners in intertidal and 

 fresh-water areas estimated by foot survey 

 method compaired with number estimated at weirs 

 in the fresh-water area and by two other 

 methods (peak count in 1960 and tag ratio in 

 1961) in the intertidal area of Olsen Creek, 

 1960-61 



The tag ratio method gave a larger estinnate 

 of the number of pink salmon spawning in the 

 intertidal area in 1961 than did the foot survey 

 method. Fish for tagging were captured in the 

 bay near the mouth of the stream, and car- 

 casses were counted daily (Helle et al., 1964). 

 Studies on the Lakelse River, British Columbia, 

 have shown that the tag ratio method of deter- 

 mining the size of spawning populations of 

 pink salmon overestimated the actual runs by 

 41.5 percent in one year and 26.6 percent in 

 another (Fisheries Research Board of Canada, 

 1962). Whether or not the tag ratio method 

 overestimated the intertidal run at Olsen Creek 

 in 1961 is not known, Helle et al. (1964), who 

 compared the estimates by this method with 

 weir estimates in the upstreann areas of Olsen 

 Creek in 1961, found that the two estimates 

 were similar for the West Fork (the tag ratio 

 method overestimated the minimal weir count 



by only 5 percent) but that the tag ratio esti- 

 mate was 41 percent larger than the weir count 

 in the £ast Fork. 



Population estimates by the foot survey 

 method were larger (four out of five times) 

 than estimates by other nnethods that were 

 known to be minimal and smaller than a tag 

 ratio estimate that was suspected of being 

 high (table 3). I therefore conclude that the 

 foot survey method gives reasonable estimates 

 of the spawning populations at Olsen Creek. 

 An annual estimate of stream life or redd life 

 is desirable, however, because these nnay 

 change from year to year. 



ABUNDANCE, TIMING. AND DISTRIBUTION 

 OF SPAWNERS 



The pink salmon run to Olsen Creek has 

 four recognized segments based on season and 

 spawning ground used: an early and a late run 

 that spawn in the intertidal zone and an early 

 and a late run that spawn in fresh water. The 

 relative numbers of fish in these groups are 

 distinctly different in odd and even years (Helle 

 et al., 1964). These four segments were present 

 in both 1962 and 1963. 



The 1962 Spawning Population 



The number of pink salmon counted on 

 periodic foot surveys of the intertidal zone of 

 Olsen Creek and the fresh-water spawning 

 areas (East and West Forks) from June through 

 September 1962 are shown in figure 5. The 

 estimates of stream life made by Helle et al, 

 (1964) for fish of the 1961 escapement were 

 used in the calculations of the total number 

 of spawners by the foot survey method. Table 

 4 presents the population estimates for the 

 various parts of the run. 



Most of the even-year line of pink salmon 

 in Prince William Sound spawn in the inter- 

 tidal area of streams. In 1962, 70 percent of 

 the total run of pink salmon in Olsen Creek 

 spawned in the intertidal area, and in I960 

 (the parent year) 75 percent used this area 

 (table 4). Of the total pink salmon escapement 

 in Prince William Sound, 70 percent spawned 

 in the intertidal zone in 1962? and 77 percent 

 in 1960 (see footnote 2). Olsen Creek received 

 7 percent of the total pink salmon escapement 

 in Prince William Sound in 1960 and 3 percent 

 in 1962.8 



7 Wallace Noerenberg. 1964. Prince William Sound pink 

 and chum salmon forecast studies. In_Forecast research 

 on 1964 Alaskan pink salmon fisheries, pp. 18-35. Alaska 

 Dep. Fish Game, Inform. Leafl. 36. 



° Wallace Noerenberg. 1961. Observations on spawning 

 and subsequent survival of fry of the 1960 salmon runs In 

 Prince William Sound, Alaska. Alaska Dep. Fish Game, 

 Mem. 5. (See also footnote 7.) 



