Table 17. — Estimates of the seal pup population, year 

 classes 1961-65, at time of marking from recoveries 

 of marked female seals killed in 1967 and 1968, 

 Pribilof Islands, Alaska 



(R+1) 



' Marked by tagging. 



^ Marked by removing the tip of the first digit on the 

 right hind flipper. 



Marked by cutting a V-notch into the leading edge of 

 the right front flipper. 



' Marked seals of the 1965 year class combined. 



combined the data from both islands, but sep- 

 arated the sexes (tables 17 and 18), 



With the exception of the 1964 -year class, 

 estimates of the number of pups from tagged 

 males recovered at age 2 have been less than 

 estimates from recoveries at ages 3 and 4 (table 

 19). Among seals killed at age Z, therefore, 

 more had tags than would be expected from 

 the rate of recovery observed at ages 3 and 4. 

 Estimates from recoveries of tagged 2-year- 

 old males also varied considerably, probably 

 because few animals of this age were taken. 



Low estimates based on tagged males re- 

 covered at age 2 may be caused by uninten- 

 tional selection for tagged animals, as de- 

 scribed in the section Tags vs. Other Marks. 

 Most 2-year-old males are less than the min- 

 imum body length limit of 42 inches (107 cm.) 

 used as a guide to select animals for killing. 

 Hence, a slight tendency to take tagged animals 

 near the lower length limit and let untagged 

 seals escape would account for the greater than 

 expected number of tagged males among ani- 

 mals taken at age 2. A similar tendency when 

 taking animals age 3 and older would have a 

 negligible effect on the estimates because most 

 seals of these ages are longer than the mini- 

 mum limit of body length. 



Table 18. — Estimates of the seal pup population, year 

 classes 1963-66, at time of marking from recoveries 

 of marked male seals killed 26 June to 2 August 

 1968, Pribilof Islands, Alaska 



Year 

 class 



Age 



Killed 

 (C) 



Marked 

 (M) 



Recovered 



(R) 



Population 

 estimate 



at time of 



marking^ 



(N) 



1963 



1964 



1965 

 1965 

 1965 

 1965 



1966 

 1966 



Years Number 



5 1,935 2 24,971 



16,912 2 24,991 



22,978 



■" 10,000 

 ^ 10,080 

 * 10,007 

 ' 30,037 



2,040 2 12,499 

 * 12,078 



112 



1,050 



588 



709 



673 



1,970 



73 

 45 



427,839 



402,179 



390,175 

 326,269 

 341,207 

 350,782 



344,764 

 535,940 



1 N_(C+1)(M+1) 



(R+1) 

 Marked by tagging. 

 ■' Marked by removing the tip of the first digit on the 

 right hind flipper. 



Marked by cutting a V-notch into the leading edge of 

 the right front flipper. 



' Marked seals of the 1965 year class combined. 

 ' Includes 9,578 seals marked by removing the tip of 

 the third digit on the right hind flipper and 2,500 

 marked by removing the tip of the second digit on the 

 left hind flipper. 



Table 19. — Estimates of the seal pup population, year 

 classes 1960-66, at time of tagging, from recoveries 

 of marked male seals in ages 2 to 5, Pribilof Islands, 

 Alaska 



"■ Estimates for year classes 1960-64 from seals marked 

 by tagging. 



Estimates from seals marked by tagging and by re- 

 ing pa 

 Estiic 

 flippers . 



moving parts of flippers. 



■' Estimates fran seals marked by removing parts of 



Estimates of the 1965 year class show that 

 the recovery rate for males given a mark was 

 higher than that for males given a tag and 



17 



