Table 13. — Tag recoveries, 26 June to 17 August 1967, from seals 

 tagged as pups in August and September of 1963 and 1964 1 on 

 St. Paul Island 



1/ Numbers of pups tagged: 12-21 August 1963 - 9,993; 

 20-25 September 1963 - 9,985; 12-21 August 1964 - 10,000; 

 20-25 September 1964 - 9,998. 



POPULATION ESTIMATES 



Estimates of the number of pups and yearling 

 males are presented in this section. Estimates 

 of the pup population are based on three 

 sources of data, tag or mark recoveries, shear- 

 ing and sampling, and complete counts. Esti- 

 mates of the yearling male population are based 

 on tag recoveries. 



NUMBER OF PUPS BORN 



Estimates of the number of pups at the time 

 of tagging were made by combining the tag 

 recovery data for St. Paul and St. George 

 Islands (table 14). We derived an estimate of 

 the total number of pups born by adding the 

 count of dead pups on land to the estimate of 

 the number of pups at the time of tagging 

 (table 15). Estimates based on recoveries from 

 males at ages 3 and 4, believed to be the most 

 accurate, show a continuous but expected de- 

 cline since I960. The estimate of 416,000 in 

 1964 (table 15), however, is still about 40,000 

 greater than the estimate from shearing and 

 sampling in that year--even with 20,000 pups 

 added to the latter as a result of shearing and 

 sampling on Sea Lion Rock. Estimates from the 



Table 14. — Estimates of the pup population at time of 

 tagging, based on tag recoveries from male seals 

 killed 26 June to 5 August 1967 from year classes 

 1962-65, Pribilof Islands, Alaska 



1 Recoveries from males tagged as pups. 



2 Recoveries from males tagged or marked as pups. 



two sources (tag recoveries, and shearing and 

 sampling) should become more nearly equal 

 because of improvements in tagging. Shearing 

 and sampling now produces the most accurate 

 estimate. The error caused by additional 

 mortality that results from the tagging of pups 

 has not been completely eliminated. 



We restricted shearing and sampling as a 

 basis for estimating the pup population to two 



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