TABLE 31.— Tag -lost to tagged ratio among male seals killed, 

 Pribilof Islands, Alaska, 1960-62 



Island of recovery 

 and year 



Year 

 class 



Seals checked 



St. Paul 1960 

 St. George 1960 



St. Paul 1961 

 St. George 1961 



St. Paul 1962 

 St. George 1962 



St. Paul 1961 

 St. George 1961 



St. Paul 1962 

 St. George 1962 



St. Paul 1961 

 St. George 1961 



St. Paul 1962 

 St. George 1962 



St. Paul 1962 

 St. George 1962 



1957 



1958 



1959 



1960 



With tag 

 lost 



With 

 tag on 



Ratio 



1 See text footnote 8, p. 30. 



both islands as a single unit. Estimates based 

 on combined recoveries for the 1958 and 1959 

 year classes are probably the most accurate. 

 The estimate for the 1960 year class must be 

 considered preliminary as it is based on only 

 130 tag recoveries. 



Table 34 lists the population estimates at 

 time of tagging the dead-pup counts, and the 

 total number of pups born, i.e., the estimate 

 at time of tagging plus the dead-pup counts. 



Table 35 gives the estimated total pup 

 population by island. The estimate for each 



island was calculated on the basis of the 

 estimated pup population at time of tagging, 

 the harem bull count, and the dead-pup count 

 for. each island. 



Although land mortality among tagged pups 

 is known to exceed that of untagged pups, its 

 effect has not been included in the population 

 estimates (see section "Effects of tagging," 

 p. 30). No reliable estimate of the magnitude 

 of this factor is yet possible. Limited data 

 show that it may be 2 to 3 percent, a figure 

 that would have no appreciable effect on 

 present estimates of the total pup population. 



41 



