Biological Characteristics of Intertidal and Fresh-Water 

 Spawning Pink Salmon at Olsen Creek, 

 Prince William Sound, Alaska, 1962-63 



By 



JOHN H. HELLE, Fishery Biologist 



Bureau of Commercial Fisheries Biological Laboratory 

 Auke Bay, Alaska 99821 



ABSTRACT 



Prince William Sound is unique among major pink salmon-producing areas in 

 that a significant portion of the spawning takes place in the intertidal zones of 

 streams. Olsen Creek is one of the major spawning streams in the sound. 



The percentage of fines (solids passing through an 0.833-mm. sieve) in 

 spawning-bed materials increased progressively from higher to lower intertidal 

 levels, i.e., higher intertidal levels contained coarser spawning gravel than lower 

 levels. 



Although less than one-third of the spawning area available in the Olsen Creek 

 drainage is subject to tidal influence, 70 percent of the total pink salmon spawners 

 occupied this area in 1962 and 30 percent in 1963. Late-run fish of the even-year 

 line spawned only in the intertidal area; fish of both the early and late runs of the 

 odd-year line spawned in both the intertidal and fresh- water areas. The size of the 

 spawning populations was estimated by a repetitive stream survey technique, which 

 is described and compared with the three methods used in I960 and 1961. 



The length of pink salmon was compared between sexes, between spawning 

 areas, and between times of spawning. Fish in the even-year line that spawned in 

 the small intertidal creeks tended to be smaller than those that used the main 

 stream, but in the odd-year line this difference was confined to females. The 

 mean lengths of females were about the same in 1962 and 1963, but females from 

 the odd-year line were more fecund. In both years a significant positive correla- 

 tion was shown between lengths of females and numbers of eggs. 



INTRODUCTION 



Prince William Sound annually produces runs 

 of pink salmon, Onco rhynchus gorbuscha , worth 

 millions of dollars. The runs have had 0,6 to 

 8.8 million fish from 1956 to 1963. ^ The pink 

 salmon of the sound differ from those of other 

 areas in that a significant portion spawn in the 

 intertidal zones of streams. Noerenberg 2 

 estimated that in 1952-61, 35 to 57 percent of 



iRobert S. Roys and Wallace H. Noerenberg. 1965. 

 Forecast of the 1965 Prince William Sound pink and chum 

 runs. In Forecast research on 1965 central Alaska pink 

 salmon fisheries, pp.4-I9.AIaskaDep. Fish Game, Inform. 

 Leafl. 65. 



2 Wallace H. Noerenberg. 1963. Salmon forecast studies 

 on 1963 runs in Prince William Sound. Alaska Dep. Fish 

 Game, Inform. Leafl. 21, 29 pp. 



the pink salmon in the odd-year lines 3 and 72 

 to 77 percent in the even-year lines spawned 

 within the stream intertidal zones. 



It is clear that spawning populations in the 

 intertidal zones of streams contribute signifi- 

 cantly to the production of pink salmon and chum 

 salmon, O. keta ; yet little is known of the en- 

 vironment itself or of the biology of the salmon 

 in this area. Studies at Olsen Bay have shown 

 that the action of the tide causes changes in the 

 flow, temperature, salinity, and dissolved 

 oxygen of the intragravel water that would 

 affect the biology of the fish in the intertidal 

 environment. The effects of most of these 



3 Pink salmon spawn and die when they are 2 years old; 

 therefore, spawners from consecutive years do not Inter- 

 breed and the odd and even years constitute separate 

 genetic lines. 



