
Table 5.--Number of harem bulls on the Pribilofs, 1911-51; comparison 
of empirical data with estimates based on fitting a logistic 


curve. 
[See headnote, table 2] 
Enpirical Empirical 
Year (counted) Theoretical Year (counted) Theoretical 
1911 1, 3 56 So 1931 9 3 233 95 195 
1912 1,358 -+--— 1932 10,088 9,867 - 
1913 15403 tne 1933 10,213 10,422 
1914 1,559 teen 1934 10,770 10,869 
1915 eyl51 aioe 1935 11,547 11,220 
1916 3,500 mannan 1936 = 11,490 
1917 4,850 ----- 1937 13,100 11,696 
1918 55344 ——== 1938 ----—- 11,851 
1919 5,158 = 1939 10,980 11,967 
1920 4,066 -—--~ 1940 11,650 12,053 
1921 3,909 --—-- 1941 12,031 12,116 
1922 - 3,562 —~——— W422 eee 12,163 
1923 3,412 Saar 1943 13,055 12,198 
1924 3,516 1/ 3,032 1944 13,374 12,222 
1925 3,526 3,808 1945 13,184 12,241 
1926 4,034 4,680 1946 12,996 12,254 
1927 4,643 5,621 1947 11,968 12,264 
1928 6,050 6,587 1948 12,200 12,272 
1929 7,187 7,531 1949 11,049 12,277 
1930 8,312 8,411 1950 11,401 12,281 
| 1951 11,259 12,283 

eas PIP RI AEC an A OY PY ELAR 1 wal OP Dn aR aE TG FER. 
1/ The logistic curve fits the observed increase (field count) of bulls 
from about 1924 on. 
It is from the hauling grounds that the commercial harvest is taken. 
Statistics of the commercial kill 
The commercial sealing season begins about 20 June and ends not 
earlier than 27 July. The beginning is determined by the arrival of 
bachelor seals in commercially important numbers, the end by two consider- 
ations. First, in order to reserve male breeding stock, the season is 
closed before all the bachelors in the commercial age classes have arrived. 
second, during the last few days of July the number of females and 2-year-old 
bachelors on the hauling grounds, and thus on the killing fields, increases 
rapidly. These unwanted animals interfere with sealing operations. In 
general, Pribilof sealing procedures have remained quite uniform since 1918. 
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