TABLE 34-. — Pup population estimates and dead-pup covmts, Pribilof Islands, 



Alaska, year classes 1953-60 



Coiint for St. Paul Island only. 



TABLE 35. — Estimates of total pup population, Pribilof Islands, Alaska, 



year classes 1958-60 



Year 

 class 



Fall pvip 



population 



estimate 



Island 



Distribution 



of harem 



bull count 



Dead pups 



Estimate of 

 total pups 



This estimate is based on tag ratios obtained 

 from the second count on St. Paul Island and 

 the dead-pup count for both islands. The 

 number of pups allotted to St. George Island 

 is determined by the relative proportion of 

 harem bulls counted on each island. Estimates 

 of the total pup population for the 1958 and 

 1959 year classes based on tag recoveries 

 from the kill is about twice the highest es- 

 timate for the 1962 year class made from 

 fall pup sampling. 



There is no reason to believe that the pup 

 population has decreased to the level indicated 

 by the 1962 estimates from fall sampling; 

 therefore, we assume that the estimate from 

 fall sampling is too low, i.e., the tag ratio 

 from sampling is too high. 



Obvious factors causing a high tag ratio are: 

 observers tend to count tagged pups and ignore 

 untagged pups; tagged pups have a higher prob- 

 ability of being included in the samples than 



44 



