Salmon Tagging Experiments Along the South Shore of 



Unimak Island and the Southwestern Shore of the 



Alaska Peninsula 



By 

 Fredrik V. Thorsteinson and Theodore R. Merrell, Jr. 

 Fishery Biologists (Research) 



Bureau of Commercial Fisheries Biological Laboratory 

 Auke Bay, Alaska 



ABSTRACT 



Sockeye, chum, and pink salmon were,captured by purse seine and tagged from 

 mid- June to mid- July 1961 south of Unimak Island and off the southwestern shore of 

 the Alaska Peninsula. A westerly migration followed by a northeasterly migration 

 was demonstrated. Tagged sockeye salmon were recovered mainly in the fisheries of 

 the Kvichak, Naknek, and Egegik Rivers of Bristol Bay; tagged chum salmon were 

 caught along the Bering Sea coast from Bristol Bay to the Yukon River; and 

 most tagged pink salmon were recovered relatively close to the tagging area. 



INTRODUCTION 



A salmon fishery has operated annually 

 along the south shore of Unimak Island between 

 Cape Pankof and Cape Lutke since the early 

 1930's. Fishing is concentrated in the vicinity 

 of Cape Lutke and lasts a comparatively 

 short time- -usually between June 10 and 30. 

 Fishing is done exclusively by purse seines 

 and drift gill nets. All species of northeast 

 Pacific salmon are taken, but sockeye 

 (Oncorhynchus nerka) , chum ( O. keta ), and 

 pink (O. gorbuscha) are most abundant. From 

 1952 '.hrough 1961, annual catches ranged from 

 200,000 to 900,000 fish, with an average of 

 390,000. The average annual catch of each 

 principal species was: sockeye, 1 75,000; chum, 

 150,000; and pink, 65,000. The 1961 catches 

 in this area were:' sockeye, 199,105; chum, 

 157,006; and pink, 18,598. 



Even-year catches of pink salmon tend to 

 be larger than odd-year catches. No cycles 

 appear in the sockeye and chum salmon 

 catches. The catch probably does not ac- 

 curately reflect the numbers of salmon in 

 the area because stormy weather frequently 

 affects the distribution and intensity of fish- 

 ing effort. Also, fishing is limited to the 

 shoreline within the 3-mile limit. 



Salmon were tagged in 1922-23 and in 

 1958 off the southwestern shore of the 

 Alaska Peninsula at sites ranging from 60 



' Catch data from State of Alaska Department of Fish 

 and Game. 



to 150 miles east of Cape Lutke (Gilbert 

 1959). Tagged sockeye and chum salmon from 

 these experiments were recovered in Bristol 

 Bay and at various points along the eastern 

 Bering Sea coast. The recoveries indicated 

 a westerly migration followed by a north- 

 easterly movement into the Bering Sea. 

 When the salmon were tagged in 1922 and 

 1923, there was no Cape Lutke fishery, and 

 in 1958 the fish were tagged too late in the 

 season to be recovered there. Only one 

 tagged salmon was recaptured in the Cape 

 Lutke fishery in 1958- -a pink salmon tagged 

 at Unga Island on June 23 and recaptured on 

 June 28. Information, therefore, was needed 

 to ascertain if the Cape Lutke fishery was 

 intercepting the same stock of migrating 

 salmon that had been tagged in early years 

 to the east and if this was the last point at 

 which they were taken south of the Bering 

 Sea. 



In 1961 the Bureau of Commercial Fish- 

 eries tagged salmon off the south shore of 

 Unimak Island and the southwestern shore 

 of the Alaska Peninsula (fig. 1) to provide 

 answers to these questions and to supply 

 information on the age composition and 

 ultimate destinations of these salmon. The 

 tagging was part of the intensified salmon 

 research program financed by the U.S. 

 Government to provide information on opti- 

 mum escapements and prediction of North 

 American salmon runs for the International 

 North Pacific Salmon Fisheries Commis- 

 sion. 



