FUR SEALS AND OTHER LIFE, PRIBILOF ISLANDS, I914. 79 



REQUIREMENTS OF A RESERVING SYSTEM. 



The requirements of a system of management for the seal herd, therefore, may be 

 stated in their simplest form as only two: (i) The preservation of those males needed 

 as breeders, and (2) the utilization by man of those not needed as breeders. To put 

 these requirements into effect, however, involves the determination of the total number 

 of seals, the proportions of various classes, the death rates from natural causes, the 

 age at which the surplus should be taken, and the method of marking or branding to 

 insure the permanent preservation of the reserves. Some of these matters may be 

 decided upon the basis of data now available, but in regard to others it is still necessary 

 to estimate. The prime requisite for a well-grounded system of reserving males is a 

 better knowledge of the natural rates of increase than we now possess. Liberal allow- 

 ances for supposed mortality answer the demands of conservatism in estimating the 

 size of the herd and the relative strength of different classes of seals, but, as shown 

 in the discussion of the census of 1914, the estimates are largely based on data obtained 

 during pelagic sealing when natural conditions were greatly disturbed. From one 

 point of view these estimates are entirely safe guides, since they are conservative 

 enough to be well within the facts, but with better data within reach there is no justi- 

 fication for using them longer than necessary. The percentage of survival to the 

 age of 3 years can be determined in a single season by the simple process of setting 

 aside a reserve of 3-year-old males and then killing all the remaining animals of that 

 class. This should be done in 1915, not only because the information is needed as soon 

 as possible, but because the conditions at that time will be particularly favorable. 

 In the first place, the total number will be smaller than in later years and therefore 

 easier to handle. Moreover, the number of pups born in 1912 — the 3-year-olds of 1915 — 

 is known from an actual enumeration, while some 5,500 of these pups were given per- 

 manent brands in 1912 and a record was kept of the few killed as 2-year-olds in 1914. 

 The presence of a certain number of these branded animals, which will be 3-year-olds 

 in 1915, will make it possible to determine with great exactness the characteristics of 

 the 3-year-olds and would greatly facilitate the restriction of killing and reserving to 

 that class. Such favorable conditions will not occur soon again, and even to approxi- 

 mate them in 191 8 would require a needless repetition of the branding done in 191 2. 



CONFINEMENT OF KILLING AND RESERVING TO ONE CLASS. 



Various considerations indicate that at present and at least for a few years to come 

 killing and reserving should be mainly confined to one class — the 3-year-olds. In former 

 years the seals taken included those of 2, 3, and 4 years of age. The twos and threes 

 are of practically the same quality, but the threes being larger, usually command a 

 •higher price. The fours, although still larger, are not as uniform as to quality, and 

 although they still have good values it is evidently poor economy to allow them to 

 reach that age before being taken. In the past the market has sometimes shown a 

 special demand for the sizes yielded by 2-year-olds, and if it should be found profitable 

 in future to cater to such a demand it may be done at least to a limited extent when 

 our knowledge of proportions and rates of increase is more definite than at present. In 

 general, however, the 3-year-olds yield the skins of highest quality and value, and while 

 the herd is comparatively small and methods are being perfected these only should be 

 taken. 



