ESTIMATING ABUNDANCE OF PINK AND CHUM 

 SALMON FRY IN PRINCE WILLIAM SOUND. 1957 



by 



Howard D. Tait and James B. Kirkwood 



Fishery Research Biologists 



Bureau of Commercial Fisheries 



U.S. Fish and Wildlife Service 



Juneau, Alaska 



ABSTRACT 



Salmon fry enumeration studies conducted on eight streams in the Prince 

 William Sound area of Alaska provided estimates of the numbers of pink and chum 

 salmon fry produced in streams of that area in 1957. The studies were conducted to 

 provide a basis for predicting returns of adult salmon. 



A method of deriving estimates of fry production from trapping experiments and 

 excavations of pre-emergent fry in intertidal gravel was presented. 



Timing and duration of migration of chum and pink salmon fry were recorded, 

 and recommendations were made for future fry sampling programs. 



INTRODUCTION 



This paper presents the methods used to 

 enumerate salmon fry that migrated from 

 streams in the Prince William Sound area of 

 Alaska in 1957. The work was pan of the Bureau 

 of Commercial Fisheries program to deter- 

 mine the causes of fluctuations and general 

 decline in the numbers of pink salmon 

 (Oncorhynchus gorbuscha) and chum salmon 

 (0. keta) that enter the Sound. 



Fluctuations in abundance can mean serious 

 economic losses to fishermen, and uncertainty 

 about the size of salmon runs expected each 



Note: --Howard D. Tait is now the Director, Division 

 of Biological Research, Alaska Department of Fish and 

 Game, Juneau, Alaska. 



year makes it difficult for the salmon canning 

 industry to plan operations from year to year 

 and complicates management of the fishery. 

 Reliable methods for predicting the size of 

 the runs would be of great benefit to the in- 

 dustry and to the regulatory agency charged 

 with insuring adequate escapement of adult 

 salmon through the fishery to the spawning 

 streams. 



The best available method of forecasting 

 salmon runs in Alaska has been based on the 

 numbers of adults spawning in the streams; 

 however, the relationship between numbers of 

 spawning adults and subsequent return from 

 the sea is not always direct. Large escape- 

 ments have yielded poor returns, and, con- 

 versely, low numbers of adult spawners have 

 sometimes produced good returns. A method 



