Estimate of the number of pups born in 1949 from sample counts 
of pups used with complete counts of harem bulls.--On carefully counted 
sample areas it was found that the average ratio of pups to harem bulls 
was 42 to 1. On the basis of accurate harem-bull counts, the ratio was 
extended to include all rookeries. Corrections were made for the variable 
abundance of seals on different types of terrain. In spite of this 
correction factor, the method is believed to provide results that are 
useful only as a check on other methods. The procedure was as follows: 
(1) Careful estimates of living pups and counts of dead pups were made on 
6 sample rookeries (table 9). (2) Using the harem—bull count for 1949, 
(teble 3) a pups-per-—bull ratio was calculated for each sample rookery. 
(3) The sample rookeries were classified according to slope of land, 
abundance of rocks, and general compactness of the harems. Each uncounted 
rookery was then allocated to the category of the counted sample rookery 
that it most closely resembled, and the pups-—to-bull ratio of the counted 
rookery was extended by means of the bull count to those rookeries where 
pups were not counted. 

Figure 10. A “rapid field estimate" of living pups. 
Gorbatch rookery. A typical late July and early August view 
of pups sleeping closely massed. This photo illustrates the 
difficulty of estimting the number of pups, especially when 
they are distributed along 8 miles of Pribilof breeding 
beaches (KWK 4& 96). 
Solis 
