Figure 3. — Beach seine trap used to capture sockeye salmon for tagging, Naknek River, 1962. Dock is at right. 



end of the net was pulled to shore, completely 

 enclosing the fish. 



Three men tagged the fish. The first dipped 

 fish from the holding pen and transferred them to 

 tubs containing an anesthetic; the second trans- 

 ferred the anesthetized fish to the tagging cradle 

 and held it; and the third attached the tag and 

 released the fish. 



Two anesthetics were used. From June 24 to 

 30, tricaine methanesulfonate (MS 222) was used; 

 from July 1 to 18, the remaining period of the 

 experiment, quinaldine was used because of its 

 more rapid action in producing anesthesia. 



A pair of 1-inch plastic disk tags was attached 

 to the fish (one on each side) with a nickel pin 

 that was inserted through the fleshy part of the 

 back about 1 inch below the base of the posterior 

 to the insertion of the dorsal fin. A different 

 color combination of tags was used each day 

 (table 1), making it possible to determine the 

 date of tagging through visual observation of 



tagged fish on the spawning grounds. The tags 

 applied to the left side of the fish were serially 

 numbered. 



Between June 24 and July 18, 1962, 6,822 

 sockeye salmon were tagged (table 1), accounting 

 for 0.94 percent of the estimated total run and 

 giving an estimated tagged to untagged ratio of 

 1:106. 



TAG RECOVERY 



Tagged fish recoveries were in the form of both 

 visual observations and actual recaptures. Ob- 

 servations provided information only on the date 

 of tagging. Recaptures yielded additional infor- 

 mation on age, length, and sex. 



SAMPLING FOR AGE, SIZE, AND SEX 



A portion of the fish captured and tagged each 

 day was sampled to determine the age, size, and 

 sex composition of the Naknek spawning escape- 

 ment. Some fish from every seine haul were 

 sampled, the exact number depending on the size 



464 



U.S. FISH AXD WILDLIFE SERVICE 



