168 



U. S. BUREAU OF FISHERIES 



■Computation of breeding cows, based on annual increase oj S per cent, and of average 



harems, in 1927 



Rookery 



Breeding cows 



1926 



1927 



Harem 

 bulls, 

 1927 



Average harem 



1927 



1926 



Increase 

 (+)or 



decrease 



(-)m 



1927 



from 1926 



St. Paul Island: 



Kitovi 



Lukanin. 



Gorbatch 



Ardiguen 



Reef- 



Sivutch 



Lagoon.- 



Tolstoi 



Zapadni— 



Little Zapadni-. 

 Zapadni Reef-.. 



Polo Vina 



Polovina Clifls-. 

 Little Polovina. 



Morjovi 



Vostochni 



Total. 



St. George Island: 



North..- 



Staraya ArtU— 



Zapadni 



South 



East Reef 



East Clifls 



8,073 



3,904 



20,499 



1,939 



41, 176 



12, 599 



1 109 



24,240 



23,294 



11, 874 



412 



8,371 



4,583 



1,669 



3,001 



33, 403 



8,719 



4,216 



22, 139 



2,094 



44, 470 



13, 607 



140 



26, 179 



25, 158 



12,824 



445 



9,041 



4,950 



1,803 



3,241 



36,075 



232 



89 



328 



41 



712 



319 



1 



391 



338 



204 



18 



180 



129 



48 



95 



791 



199,146 215,001 



16,244 

 12,240 



1,728 

 405 



3,723 

 10,628 



17,544 

 13, 219 



1,866 

 437 



4,021 

 11,478 



Total 44,968 | 48,565 



Total (both islands) 244, 114 i 263, 566 



3,916 



290 



166 



57 



19 



57 



148 



37.58 

 47.37 

 67.50 

 51.07 

 62.46 

 42.66 

 40.00 

 66.95 

 74.43 

 62.86 

 24.72 

 50.23 

 38.37 

 37.56 

 34.12 

 45.61 



54.90 



60.50 

 84.74 

 32.74 

 23.00 

 70.54 

 77.55 



66.80 



38.08 

 4L53 

 74.27 

 51.03 

 68.06 

 45.16 

 36.33 

 64.47 

 72.34 

 64.18 

 22.89 

 50.43 

 38.84 

 37.09 

 34.49 

 51.07 



-.50 



+5.84 



-6.77 



+.04 



-5.60 



-2.50 



+3.67 



+2.48 



+2.09 



-1.32 



+1.83 



-.20 



-.47 



+.47 



-.37 



-5.46 



57.26 



-2.36 



85.05 

 90.00 

 41.14 

 27.00 

 79.21 

 85.02 



80.88 



4,643 



56.77 



-24. 55 

 -5.26 

 -8.40 

 -4.00 

 -8.67 

 -7.47 



-14.08 



I Pups counted in 1926 and 1927. 



The average harem for St. Paul Island in 1927 was 54.90, for St. 

 George Island 66.80, and for the whole herd 56.77. The greatest 

 decrease on St Paul Island was 6.77 on Gorbatch rookery and the 

 greatest increase was 5.84 on Lukanin rookery. On St. George 

 Island the average harem on eaeh rookery decreased. The decrease 

 for the whole herd was 3.74. 



PUPS AND COWS 



In 1917 a complete pup count was made, and again in 1922. Dur- 

 ing this period there was no indication that the seal herd did not 

 make a noiTiial growth. The pups and cows increased annually at 

 the rate of approximately 8 per cent. Since 1922, with no abnormal 

 conditions, it has been assumed that the annual increase was 8 per 

 cent. In 1927 pups were counted upon Lagoon rookery only. There 

 was only 1 harem with 40 cows. 



The number of dead pups observed during the harem-bull count 

 appeared to be about the same as normally appear each year. Con- 

 sequently the same percentage of dead animals has been appUed to 

 each rookery. 



