Table 7. — Summary of tag loss for male seals tagged 

 at age 1 or older, Pribilof Islands, Alaska 



2S 

 2S 

 2S 



Total 



2T 

 2T 



Total 



2U 



Years 



Number Number 



332 



108 



0.14 



-s r — ; where n, = number recovered with 



1 one tag lost; 



n 2 = number recovered with 

 no tag loss. 



Tags vs. other marks. — Tag loss and mor- 

 tality of tagged animals (greater than that of 

 untagged animals) have shown that the cattle- 

 ear tag is not ideal for marking seals. In 1965 

 and 1966, some pups were marked by removing 

 part of a nipper and others were marked by 

 tagging (table A-17) to determine if "flipper 

 marks" were better. Table 8 gives the recov- 

 eries of males from these two year classes taken 

 in the kill since 1967. 



In 1968 the recovery rate for seals marked 

 by removing part of a flipper was 1.17 times 

 that of tagged animals for the 1965 year class. 

 Data collected in 1969 from the 1965 year class 

 again reflected a higher recovery rate for flip- 

 per marks. Data for the 1966 year class, how- 

 ever, show a higher recovery rate for tagged 

 animals. Why the data for the two year classes 

 are contradictory is not known. Thus, no con- 

 clusion can be made at this time on the rel- 

 ative effectiveness of the two methods of mark- 

 ing. The recovery of 4-year-old males in 1970 

 from the 1966 year class will give additional 

 information. 



Ancel M. Johnson 



POPULATION ESTIMATES 



The number of animals in various segments 

 of the fur seal population is estimated from 

 mark- recapture data. In 1969, we made esti- 

 mates of the number of pups born each year 

 from 1964 to 1967 and in 1969; the number of 

 yearling males in the years 1965 to 1968; the 

 number of 2-year-old males in 1966, 1967, and 



Table 8. — Summary of recoveries of seal pups, year classes 1965-66, marked by two 

 methods, Pribilof Islands, Alaska 



1 Tip of first digit of right hind flipper sliced off. 



2 V-notch cut into edge of right front flipper near tip. 



3 Tip of third digit right hind flipper and second digit left hind flipper sliced off. 



14 



