Page:Popular Science Monthly Volume 54.djvu/680

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 sought in more pertinent statistics, drawn from the breeding rookeries themselves.

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 degree 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 unusual 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 hundred 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.	Datequota filled.	Hauling grounds driven.	Numberof drives.	Killedon land.	Killedat sea.
1879	16	71	36	110,411	8,557
1880	17	78	38	105,718	8,418
1881	20	99	34	105,063	10,382
1882	20	86	36	99,812	15,551
1883	19	81	39	79,509	16,557
1884	21	101	42	105,434	16,971
1885	27	106	63	105,024	23,040
1886	26	117	74	104,521	28,494
1887	24	101	66	105,760	30,628
1888	27	102	73	103,304	26,189
1889	31	110	74	102,617	29,858