ALASKA FISHERY AND FUR-SEAL INDUSTRIES, 1930 101 



of appioximately 33 per cent over the previous season. Some ques- 

 tion arose, therefore, as to whether this was an extremely favorable 

 year due to less severe conditions at sea, causing a lower mortality rate 

 for that particular generation of seals, or whether it was due to a 

 natural recovery on account of a larger branded reserve. It was felt 

 by many that it would not be possible to equal or at least to exceed 

 the killings of 1929 during 1930. Applying an average rate of in- 

 crease of 8 per cent to the number of 3-year-old males killed and to the 

 estimated reserve in 1929 would make 41,123 killable 3-year-old male 

 seals and 14,730 of the same class to be reserved in 1930. 



There were actually killed at the Pribilof Islands during the summer 

 sealing season of 1930, 41,409 3-year-old males. In addition there 

 were marked and reserved for breeding purposes 6,539 3-year-old 

 males, making a total of 47,948 3-year-old males actually handled 

 out of the estimated total of 56,280 credited to the islands. This 

 makes an actual estimated reserve of 14,871 to be compared with 

 14,730, the number needed to provide an increase of 8 per cent over 

 the previous season's estimated requirements. 



The 3-year-old male seals were comparatively slow in appearing this 

 season, but arrived in larger numbers than usual toward the end of 

 the season. A great many unmarked 3-year-olds were observed on 

 the haiding grounds after killing and reserving operations had been 

 discontinued. It was, therefore, evident that a sufficient number 

 of animals had been reserved to amply take care of breeding require- 

 ments. 



BULLS 



A census of harem and idle bulls was taken on St. Paul Island 

 between July 15 and July 20, inclusive, and on St. George Island 

 between July 21 and July 24, inclusive. On St. George Island, A. J. 

 Messner and C. M. Hoverson counted Zapadni and South rookeries. 

 All other rookeries, on both islands, were counted simultaneously by 

 A. Christoffersen and the writer. A double check of the number of 

 animals on each rookery was therefore secured, thus minimizing the 

 possibility of error. 



It was again impossible to count Sivutch rookery on Sea Lion 

 Rock. To continue indefinitely to increase the number of harems, 

 and to continue to apply the average rate of increase for cows and 

 pups will, in time, result in crediting to this rookery a much greater 

 number of animals than could possibly crowd into such a small area. 

 The surplus bulls, cows, and pups which would normally be credited 

 to this area must of necessity move to other rookeries. For the 

 present, or until weather conditions permit an actual count, it seems 

 best to continue this method rather than to spread the increase over 

 the various rookeries on St. Pavd Island; though this may, in time, 

 show too great a number of animals on Sivutch, it will not change the 

 proportionate increase in the total number of animals in the herd. 



On South rookeiy, St. George Island, the number of harems con- 

 tinued to increase to such an extent that even though the number of 

 cows increased at the normal rate the average harem for this rookery 

 has been reduced to 6.41. As a matter of fact, the number of cows 

 on this rookery has increased at a much greater rate than 8 per cent, 

 even though this figure still applies to the increase of the herd as a 

 whole. South rookery has apparently increased at the expense of all 

 other rookeries on St. George Island. 



