104 



U. S. BUREAU OP FISHERIES 



St. George Island now brings the average harem for both islands down 

 to what most authorities consider approximately the correct figure. 

 It is hoped that this condition will remain about constant. 



Knowing the number of harems, the average size of each has been 

 determined on the basis of an average increase of 8 per cent for cows. 

 The increase for each particular rookery will vary considerably from 

 year to year, but the average rate of increase for the islands as a whole 

 will remain about constant. The average increase and the average 

 harem for each rookery may therefore vary considerably from year 

 to year and may be far from correct for any given rookery, but will 

 be about right for all the rookeries on both islands. A sharp increase 

 or decrease in the number of harems on any given rookery will be 

 compensated for by a sharp decrease or increase on the other rookeries. 



Computation of breeding cows, based on annual increase of 8 per cent, and of average 



harems, in 1930 



Rookery 



St. Paul Island: 



Kitovi 



Lukanin 



OorbatPh 



Ardiguen 



Reef 



Sivutch 



Lagoon (actual count pups) 



Tolstoi_ _ 



Zapadni 



Little Zapadni 



Zapadni Reef 



Polovina 



Polovina Cliffs... 



Little Polovina 



Morjovi 



Vostochni. 



Total 



St. George Island: 



North 



Staraya Artil 



Zapadni 



South.- 



East Reef 



East Cliffs... 



Total-.. - 



Total (both islands) 



Breeding cows 



10, 170 



4,917 



25, 823 



2,443 



51, 870 



15, 872 



112 



30, 535 



29, 345 



14, 958 



519 



10, 545 



5,774 



2,103 



3,780 



42, 078 



250, 844 



20, 464 

 15, 419 



2,176 

 510 



4. 690 

 13, 3S8 



56, 647 



307, 491 



10, 984 



5,310 



27, 889 



2,638 



56, 020 



17, 142 



113 



32, 978 



31, 693 



16, 155 



561 



11.389 



6,236 



2,271 



4,082 



45, 444 



270, 905 



22, 101 

 16, 653 



2,350 

 551 



5, 065 

 14, 459 



61, 179 



332, 084 



Harem 

 bulls. 

 1930 



302 



109 



617 



77 



1,127 



390 



2 



729 



581 



359 



29 



418 



204 



96 



226 



1, 557 



6,823 



478 

 354 

 144 

 86 

 134 

 293 



1, 489 



8,312 



Average harem 



1930 



36.37 

 48.72 

 45. 20 

 34.26 

 49.71 

 43.95 

 56.50 

 45.24 

 54.55 

 45.00 

 19.34 

 27.25 

 30.57 

 23.65 

 18.06 

 29.19 



39.70 



46.24 

 47.04 

 16.32 

 6.41 

 37. 80 

 49.35 



41.09 



39.96 



1929 



39.11 

 47.28 

 50.93 

 50.89 

 46.19 

 42.32 

 56.00 

 56.23 

 60.38 

 50.03 

 19.22 

 30.65 

 30 55 

 38.94 

 22.77 

 28.60 



41.82 



47.48 

 47.74 

 23. 65 

 10.62 

 47.86 

 67.96 



47.64 



Increase 

 (+) or de- 

 crease (—) 



in 1930 

 from 1929 



-2.74 

 +1.44 

 -5.73 

 -16.63 

 +3.52 

 +1.63 



+.50 

 -10.99 

 -5.83 

 -5.03 



+.12 

 -3.40 



+.02 



-15.29 



-4. 71 



+.59 



-2.12 



-1.24 

 -.70 

 -7.33 

 -4.21 

 -10.06 

 -18. 61 



-6.55 



-2.83 



PUPS AND COWS 



Pup counts of 1917 and 1922 showed an average rate of increase 

 of 8 per cent. The large number of seals on the rookeries made it 

 impracticable to continue making a pup count on all rookeries there- 

 after. The average rate of increase as determined from the before- 

 mentioned counts has therefore been used continuously since 1923. 

 Pup counts could still be made on the smaller rookeries; but as there 

 are innumerable factors which enter into a varying increase or decrease 

 of any particular rookery but which do not prevent the average 

 increase of the herd as a whole, it would be extremely confusing to 



