
APPENDIX C 
Size of the average harem 

The "average harem" has been defined as: (total number of 
pups born) / (count of harems, i.e., harem bulls, in mid—July). It was 
first serlously studied in 1912. From 1912 to 1924, computations of the 
size of the average harem were based on the firm evidence of complete 
and partial counts of pups and bulls (U. S. Fish and Wildlife Service, 
1947, p. 75). Between 1912 and 1916 the average harem decreased steadily 
in size as a result of the closed season on commercial sealing and the 
resulting increase of males (table 17). The all-time low of 26 and 27 
reached in 1917 and 1918 probably represents the natural primitive size 
of the average harem. In the 10-year period 1927-36, when commercial 
sealing had been carried on quite uniformly for two decades, the average 
harem was fluctuating around a mean of 43. Then, as the computation 
system failed to adapt itself to a changing herd, the estimated average 
harem began to rise. By 1947 (on paper) it had reached 95, a figure 
at variance with field observations. 
(All present evidence suggests that a realistic estimate of 
size today should be not less than 40 nor more than 50. The results of . 
the current study are listed below: 
Estimated average harem 
1947-48. St. Paul Island, except Ardiguen and Sivutch 
rookeries, from A-tag recoveries; 440,000 pups + 9,645 bulls. . 46 
1949. St. Paul Island, 6 out of 15 rookeries, from actual 
count of pups; 66,600 + 1,794 bulls... 1 2 0 we ew eh ew we 8 
1951. St. Paul Island, from rapid field estimate of pups; 
359,400 pups + 9,434 bulls . 2. 2 eee ee eee we ew ee 
1940. Zapadni Reef rookery (a small breeding ground which 
has continued to grow, doubling its size between 1940 and 
1949), from actual count of pups; 3,250 pups + 68 bulls .... 
_ 1949. Zapadni Reef rooxery, from actual counts of pups; 
é, 725 pups = lA2 bulls * * e e e e e e e e td] 6 . e * e e e . e 
1951. dZapadni Reef rookery, from actual count of pups; 
6, 303 pups é VAR bulls e . * . . s e ° e « e ® e e e e ty ° e e 
1951. Kitovi rookery, "amphitheater" area only, from daily 
observations (Bartholomew, 1951, MS); 780 pups = 20 bulls... 
1951. Kitovi rookery, from rapid field estimate of pups; 
16,877 pups > 500 bulls * «© © @® #@ #® #® @ #© #8 #@© @© # #® @© @ #@ @ @# © 
1947-51. All-Pribilof, from the trend of the commercial 
harvest; 590 , 000 pups = 11,575 bulls > 8 e@ © #® © @© #® © # @ # © 
1947-51. Al1-Pribilof, from the trend of the harem bull 
count; 550,000 pups + 11,575 bulls . . 2. «2 2 we ew we we ww ow 
=5 i= 
33 
AB 
47 
AL 
39 
