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FIGURES 
Page 
A fur-seal rookery at the height of the pupping 
S€A@SON « 2 6 © © s © ee ew ew ww ww we hw hf lhe FYOntispiece 
The-<Pur=sealetooch iw accept es wee se Ao aot ee 5 
Social structure of the breeding ground ......e.e 6 
The harem-bull count .. . . « « 6 «© ©» «© © © © © ww ew 9 
Idle bulls... ee ete Te er ee a 10 
A young harem pull an eh ai atl a deeer's be apceste tte 14 
. Measuring the length of a bachelor Beall &, Lets mie wet oes. Be 15 
PU CAE OTS oie Mi sect nealet |g ietek sa eayewbae un et oe Cer Sheela) eet Ge el 
A sample count of living pups ......s«+.+«e« e eee 23 
A rapid field estimate of living pups .....e+e.«-. an 
A count. of dead: pups... so aise ae (8 ee a eh eS wee 8 25 
. Aerial photograph of a portion of Polovina rookery... 26 
Counted elements of the seal herd, 1912-51 . ‘ , ho 
. Pelagic sealing for research purposes off Japan in 1952 ks 
- Pelagic sealing by aborigines off Southeast Alaska in 
TROLS ss coasters See miata Res adie Na ia: weed “alee atlh tear Wave SD Sle en tot "e" Mcp 46 
TABLES 
Published computations of the size of the seal herd 
by years, 1911-47 ....... NE es ae 3 
Number of harem and idle bulls sounted emma ty: on 
the Pribilofs, 1911-51... . ‘ : . ns 8 
Harem and idle bulls counted in 1949, 1950, a 1951, 
by rookeries... . : ‘ oe 11 
. Comparison of St. Paul and St. Gore “Telands “with 
respect to number of harem bulls and number of seals 
eT ded eV O26 =54. we 5. 6S eetietne sewers: caarer sacle: 2hLaald 12 
Number of harem bulls on the Pribilofs, 1911- 513 
comparison of empirical data with estimates based on 
fitting a logistic curve... . . ter 13 
Number of group-III male seals killed annual yee on the 
Pribilofs, 1918-51; comparison of empirical data with 
estimates based on fitting a logistic curve .... 16 
Number and estimated ages of male seals killed on the 
Pribilofs, 1945-52 ..... : ot er 17 
Number of pups counted on the Pribilofs, 1912- oh , ee 20 
. Size of pup class in 1949 as derived from sample 
counts of pups with complete counts of harem bulls . . 27 
Size of pup class in 1949 as derived from sample 
counts of pups with ground-area measurements ..... 28 
Mortality of pups on the Pribilofs in selected years 
from-Is96? tor bO5le “ay eee des % Se Oman rau fy 30 
. Mortality of pups on the Pribilofs in 1950, by 
TPOOKSTIOS® 4)", wacwtellers tet Woes (tale eek Sete, cee pate eee a te 31 
iv 
