Table 29. — Dead -pup counts, sample areas, 

 St. Paul Island, 1963 



Estimates From Tagged Males 



The tag lost to tagged ratios for 3-, 4-, and 

 5- year- old males were similar for both islands. 

 Differences between islands in the tag lost to 

 tagged ratios among 2-year-old males and 

 females were observed. The ratio for males 

 taken on St. Paul Island was 5.00:1 and for 

 those taken on St. George Island, 0.62:1. The 

 ratios for females were 1.74:1 for St. Paul 

 Island and 0.08:1 for St. George Island. 



The proportion of 2 -year -old males that were 

 marked was also different for the two islands. 

 Of 667 killed on St. Paul Island, 126 or 19 per- 

 cent were tagged or had lost their tags; only 

 52 or 11 percent of 489 2-year-old males 

 taken on St. George Island were marked. There 

 is no apparent reason for these discrepancies 

 other than the possibility that some natural 

 marks or scars were mistaken for the true 

 "V-notch" checkmark of the 2-year-old. 

 Changes in the 1963 data will be made, how- 

 ever, only if data collected in 1964 indicate 

 a valid reason for doing so. 



Table 30. — Percent of complete rookery dead -pup counts represented by sample-area 



counts, St. Paul Island, 1956-63 



Rookery 



1956 



1957 



1958 



1959 



1960 



1961 



1962 



1963 



Mor jovi 



Vostochni 



Little Polovina 1 . 



Polovina 1 



Gorbatch 



Reef 



Tolstoi 



Little Zapadni... 

 Zapadni 



42.0 

 20.6 

 51.6 

 26.3 

 33.1 

 30.2 

 52.3 

 39.2 

 51.3 



33.1 

 25.1 

 55.5 

 36.6 

 31.0 

 25.6 

 43.8 

 28.3 

 52.2 



29.8 

 14.4 

 61.3 

 48.5 

 68.8 

 46.3 

 48.4 

 30.0 

 50.9 



Percent 



30.8 

 29.0 

 56.0 

 42.3 

 38.6 

 31.0 

 44.9 

 31.6 

 47.7 



45. 

 22. 



51. 



65. 



30.0 



26.7 



35.9 



30.7 



51.5 



44.8 

 23.0 

 49.0 

 67.6 

 30.1 

 28.2 

 40.4 

 32.2 

 49.7 



40.1 

 21.8 



45.6 

 24.5 

 44.3 

 33.0 

 44.4 



37.2 

 24.5 

 53.7 

 41.3 

 37.4 

 29.6 

 30.8 

 36.4 

 43.7 



Sample areas not counted separately in 1962. 



POPULATION ESTIMATES 



The data for making estimates of the pup 

 population are derived from three sources: 

 (l)The proportion of each age class taken in 

 the kill that was tagged or had lost tags; 

 (2)the marked to unmarked ratio in samples 

 of live pups; and (3) the total count of pups on 

 one rookery. Estimates based on the recovery 

 of tags and checkmarks from the kill have 

 been made since 1947. Sampling of live pups 

 began in 1961 and has been continued as an 

 experimental technique for estimating the 

 number of pups the year they are born. A total 

 count of live pups on a single rookery was at- 

 tempted in 1963 for the first time since 1951. 



Because male seals from a given year class 

 are taken at various ages (2-6) over a period 

 of 5 successive years, all or parts of the kill 

 and tag recovery data can be used to estimate 

 the size of the pup population from which the 

 animals were derived. The estimates of each 

 year class shown in table 31 were based on 

 the kill of each age class in 1963. Data re- 

 covered from the 1958-60 year classes atages 

 3 and 4 were combined to make the estimates 

 given in table 32. The combined kill and tag 

 recovery data obtained from a year class at 

 all ages can also be used to make pup popula- 

 tion estimates. 



24 



