FUR SEALS AND OTHER LIFE, PRIBILOF ISLANDS, I914. 75 



EFFECT OF PELAGIC SEAUNG STILL EVIDENT. 



The treaty abolishing pelagic sealing became effective December 15, 191 1. There- 

 fore, kilUng at sea was going on in the summer of 191 1, and although only 14,511 

 skins were taken, and these may have included animals from the Russian and Japanese 

 herds, the usual failure to retrieve all seals killed and the starvation of pups as the result 

 of the death of their mothers must have made the losses to the herd much greater than 

 the recorded catch. Since 191 1 no seals have been taken at sea except the negligible 

 few speared from canoes by natives according to law. The patrol of the fleet of revenue 

 cutters has been continued but no sealers or marauders have been detected. The 

 nature of pelagic sealing was such that it could not fail to leave the herd in a very abnor- 

 mal condition. The number of seals killed and the proportions of different classes 

 taken at sea were necessarily quite fortuitous. Young cows, old pregnant cows, bach- 

 elors, and even old bulls were killed indiscriminately. It is possible that some of the 

 resulting irregular proportions may have had chance compensation from year to year, 

 but there can be little doubt that the cessation of pelagic sealing left the proportions of 

 young and old breeding seals in far from normal condition. The breeding life of the 

 bulls is 7 to 8 years and of the cows 10 to 11 years. This being the case, and other things 

 being equal, about one-sixth of the bulls and about one-tenth of the cows would die 

 each year of old age. The proportion of each age from the youngest to the oldest would 

 be evenly graded and reliable calculations of the general rate of increase could be deducted 

 from the birth rate and the death rate. 



It is evident that these proportions can not be reestablished until all the seals 

 subject to pelagic sealing have died and been replaced by others. This will require 12 

 to 14 years, although approximately natural conditions may be expected somewhat 

 sooner. Seals bom in 191 1 will be 12 years old in 1923 and the death rate among breed- 

 ing females will then be practically normal. That abnormal conditions prevail at present 

 is evident from the lack of a substantial increase of breeding cows in 191 4 which can 

 not be satisfactorily explained except on the assumption of an excessive death rate 

 among old cows due to pelagic sealing in former years. This has been referred to else- 

 where (see p. 43). 



Although the effect of pelagic sealing on the breeding herd will linger for years, it 

 can have only a slight and indirect influence on the abundance of young male life. The 

 combined effect of no killing at sea and very limited killing on land in the three seasons 

 since 191 1 has already produced an overabundance of young males. The propor- 

 tion of these that will be needed in later years as breeders is no greater than it would 

 be if there had never been an undue reduction of male life. The preservation of more 

 than this proportion, therefore, is no more justified now than it ever would have been 

 or ever will be. Although the birth rate may fluctuate for some years as the result of 

 irregular mortality of old cows, a reservation of males for breeders based on a regular 

 increase of cows could not fail to be ample since none of the males so reserved would be 

 old enough to go out of service before normal conditions were restored. So far as the 

 effects of pelagic sealing are concerned, therefore, killing and reserving of males need 

 not be postponed. 



