Table 14. --Estimates of the pup population based on tag 



recoveries from male seals killed in 1966 from year classes 

 1961-64, Pribilof Islands, Alaska 



Years Number Number Number 



1961 5 1,770 49,921 379 



1962 4 16,030 49,908 1,953 



1963 3 31, 106 24, 971 1, 845 



1964 2 3, 533 24, 991 212 



Number 

 232, 663 

 409, 463 

 420, 804 

 414, 656 



marked-to-unmarked ratio, and the population 

 on St. George Island was sampled once. The 

 first and second estimates for St. Paul Island 

 (excluding Sea Lion Rock) differed by about 

 30,000 (table 16). An estimated 18 percent of 

 the total pup population on the Pribilof Islands 

 was born on St, George Island. 



To determine the accuracy of the estimates, 

 we counted all the pups on three St, Paul 

 Island rookeries. The mean of the two esti- 

 mates was 5 percent higher than the total 

 counts (table 17), The estimate for the Pribilof 

 Islands (360,000) does not include pups that 

 died before the shearing--probably 15,000 to 

 20,000. Therefore, the total number of pups 



born on the Pribilof Islands in 1966, estimated 

 by this method, is about 380,000. 



Uncorrected estimates of the number of pups 

 at the time of marking for year classes 1961-66 

 on St. Paul Island (table 18) were expanded by 

 adding counts of dead pups, then multiplying 

 the number of pups born on St, Paul Island by 

 1.25 to represent estimates of the total num- 

 ber of pups born on the Pribilof Islands 

 (table 19). 



Table 15. --Estimates of the pup population based on tag 



recoveries from male seals and the count of dead pups, year 

 classes 1960-64, Pribilof Islands, Alaska 



1/ Estimates are based on tag recoveries from males of the 

 year class killed at ages 3 and 4 for year classes I960, 1961, 

 and 1962; at age 3 for year class 1963; and at a£,e 2 for year 

 class 1964. 



Table 16. --Estimates of the pup population based on shearing and sampling, year class of 1966, Pribilof Islands, Alaska 



22 



