Pink Salmon, Oncorhynchus gorbuscha, 



Tagging Experiments in Southeastern 



Alaska, 1938-42 and 1945' 



ROY E. NAKATANI,^ GERALD J. PAULIK,' and RICHARD VAN CLEVE' 



ABSTRACT 



A total of 20,532 pink salmon {Oncorhynchus gorbuacha) were tagged and released in 

 southeastern Alaska north of Sumner Strait during the years of 1938 to 1942 inclusive, and in 

 1945. The recovery of 7,027 of these tags in the fish traps confirmed the findings of other in- 

 vestigators that the pink salmon stocks of the northern part of southeast Alaska are separate 

 from those in the southern part. They also show that pink salmon enter the northern part of 

 southeast Alaska through two paths: (1) through Icy Strait, and (2) through the lower end of 

 Chatham Strait. No evidence was found of movement through Peril Strait from Salisbury 

 Sound into Chatham Strait. The centers of density of each group of tags appeared to move in a 

 consistent manner, but a smaller number of tags from each release were dispersed throughout 

 the northern part of southeastern Alaska. Differences were noted between the movements of 

 fish in odd and even years. Also a larger proportion of earlier tagged fish moved to recovery 

 locations father inland. In all areas and in all years the fishing season closed about the time of 

 the greatest abundance of fish in the fishery, therefore the later parts of the runs were not 

 studied. Apparently the 1941 run was the largest and that in 1945 the smallest. Migration rates 

 were studied by plotting the catch per trap as well as by the recovery of tags. The latter showed 

 movements of 9.05 to 33.37 miles per day. Survival rates computed for thirty releases with total 

 tag recovery periods of two or more weeks averaged 0.384. Weekly exploitation rates varied 

 from 0.142 to 0.452 averaging 0.250. The weekly F exponential rate of fishing averaged 0.514. 

 Recoveries of tags from seines were not used since their proportion of tags recovered was less 

 than one-half their proportion of the catch. Recommendations are made for future tagging ex- 

 periments based upon the results of this analysis. 



INTRODUCTION 



From about 1920 to 1950 the U.S. Fish and Wildhfe 

 Service (FWS) collected considerable data on Alaska 

 fisheries. An inventory of these data, made under a 

 contract between the University of Washington 

 College of Fisheries and the FWS, disclosed records of 

 pink salmon, Oncorhynchus gorbuscha, tagged in the 

 northern part of southeastern Alaska (Fig. 1) in 1938- 

 42 and 1945. A total of 20,532 tagged fish were released 

 in 55 tagging experiments during the 6 yr; 7,027 of the 

 tags were recovered. In this report the tagging and 

 recovery data are analyzed; supplemented by records 

 of the daily catches of pink salmon from about 100 

 traps that operated in the area in the years covered by 

 the experiments. 



'Contribution No. 401 from the College of Fisheries, University 

 of Washington. 



'Assistant Director, Fisheries Research Institute, College of Fish- 

 eries, University of Washington, Seattle. 



'Deceased. Formerly Professor, College of Fisheries, University 

 of Washington, Seattle. 



'Professor, College of Fisheries, University of Washington, 

 Seattle. 



All recovery and catch data were transferred to 

 punch cards and processed through an electronic 

 digital computer at the Research Computer 

 Laboratory, University of Washington. Details of 

 programming for the different analyses, including 

 tables of the data used in the computations, are on file 

 at the National Marine Fisheries Service Auke Bay 

 Fisheries Laboratory at Auke Bay, Alaska, and at the 

 College of Fisheries.' Past reports on salmon tagging 

 experiments in Alaska include those by Rich (1927), 

 Rich and Suomela (1929), and Rich and Morton 

 (1930). 



The tagging experiments covered in this report 

 must be evaluated with a full understanding of the 

 restrictions imposed on the staff originally responsible 

 for them. The difficulties involved in executing a 

 tagging and recovery program covering an area the 

 size of the northern half of southeastern Alaska and 

 involving a fishery as complex as the pink salmon 



'Nakatani, R. E.. G. J. Paulik, and R. Van Cleve. 1963. Analysis 

 of past Alaskan pink salmon tagging experiments, 19.38-1945. Un- 

 published manuscript, 163 p. Fisheries Research Institute, Univer- 

 sity of Washington, Seattle, WA 98195. 



