
Table 12.--Mortality of pups on the Pribilof Islands in 1950, by rookeries. 

wh B C D E 
“4 Percentage con— Number of pups 
RRs es ae tribution of born, based on 
Number of Number of each rookery to column C per- Estimated 
dead pups harems the harem count centages and percent 
counted counted from column B 530,900 total mortality 
Rookery 
pups 
St. Paul Island 
Ardiguen 170 105 0.92 4,876 3 
Gorbatch 2,810 845 7.41 39,273 7 
Kitovi - —_—«1,160 512 4.49 23,797 5 
Little Polovina 1,740 210 2.37 12,561 14 
Little Zapadni 2,120 498 4.37 23,161 9 
Lukanin 770 184 1.61 8,533 9 
Morjovi . 3,000 . 579 5.08 26,924 11 
Polovina ) 5,660 312 2074 14,522 39 
Polovina Cliffs 3,800 649 5.69 30,157 13 
Reef a/ 9,520 1,587 13.92 73,776 13 
Sivute 150 1.32 6,996 16 
Tolstoi . 4,230 1,055 9.25 49,025 9 
Vostochni 13,120 1,510 13.24 70,172 19 
Zapadni 4.3660 1,028 9.02 47,806 10 
Zapadni Reef 660 158 1.39 6 
Subtotal 545520 9,442 82.82 438,946 12.4 
ot. George Island 
East Cliff 217 1.90 10,070 
East Reef 360 110 0.96 5,088 7 
North 770 (6.75 35,775 
South 214 1.88 9,964 
Staraya Artil 386 3.39 17,967 
Zapadni 262 2.30 12,190 
Subtotal 360 1,959 17.18 91,054 
Lota “both + =.= ap a peor kee ae aS og rae ees mere oe le” 
islands 54,880 11,401 100.0 530,000 
1/ Explanation of columns 
A--Dead pups counted on all St. Paul rookeries except Sivutch, 
26-30 August; on St. George, counted on East Reef only, 2 August. 
B~—-Annual harem-bull count for 1950, 15-25 July. 
C~~For each rookery the percentage. equals column B + 11,401 x 100. 
D--The value 530,000 total pups born on the Pribilofs is derived 
from tag returns. 
E--Column A/column D x-100, or pup mortality on land as of 26-30 August. 
2/. Estimated on the basis of aerial photos taken 15 July 1948. To Sivutch there 
are assigned 150 harem bulls, 50 idle bulls, and 6,996 pups, with an estimated 
pup mortality of 15.7 percent. 
=3]- 
