658 



POPULAR SCIENCE MONTHLY. 



taken as an actual measure of such decrease. A number of other factors must 

 he taken into consideration, and the real measure of decrease must be sougbt 

 in more pertinent statistics, drawn from tbe breeding rookeries tbemselves. 



We have already noted that in that portion of the period, 1871 

 to 1889, which falls prior to 1884, thirteen years in all, no difficulty 

 was experienced in securing the full quota, and it may be added that 

 this was completed not later than July 20th. A retardation of the 

 date at which the quota can be filled is a direct indication of the de- 

 gree of exhaustion of the hauling grounds. In marked contrast with 

 these earlier years stand the conditions of 1896 and 1897, when 

 greatly reduced quotas only were obtained, notwithstanding the un- 

 usual prolongation of the driving period. 



The statement here made that the difference between the quotas 

 of 1896 and 1897 is not an actual measure of decline in the breeding 

 herd requires explanation. The quota of any year is dependent upon 

 the birth rate of three years previous, killable seals being males of 

 approximately three years of age. The difference noted, therefore, 

 while not indicative of the actual decrease for the seasons 1896 and 

 1897, is a direct measure of such decrease for the seasons of 1893 and 

 1894, when the seals in question were born. 



That the rate of decline as thus shown was greater in 1893-94 

 than in 1896-97 is explained by the fact that, whereas only 30,000 

 seals were taken at sea in 1893, 60,000 were taken in 1894; while 

 in 1896 43,000 were taken as against only 25,000 in 1897. In other 

 words, the pelagic catch of 1894 exceeded that of 1893 by one hun- 

 dred per cent, while that of 1897 fell seventy-two per cent below that 

 of 1896. It is not, therefore, strange that the quota of 1897 should 

 show a reduction of thirty per cent as against one of twelve per cent 

 in the breeding herd for the same year. 



3. From these data it is plain that the former yield of the hauling grounds 

 of the Pribilof Islands was from three to five times as great as in the years 



* This table of statistics need not be quoted here in full. The following section, 

 embracing the ten years prior to 1889 and including 1884, will suffice: 



Year. 



1879 



1880 

 1881 

 1882 

 1883 

 1884 

 1885 

 1886 

 1887 

 1888 

 1889 



Killed on 

 land. 



110,411 

 105,718 

 105,063 

 99,812 

 79,509 

 105,434 

 105,024 

 104,521 

 105,760 

 103,304 

 102,617 



Killed at 

 sea. 



8,557 

 8,418 

 10,382 

 15,551 

 16,557 

 16,971 

 23,040 

 28,494 

 30,628 

 26,189 

 29,858 



