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U. S. BUREAU OF FISHERIES 



AGE CLASSES 



The age class of a male seal belonging to the Pribilof Islands herd 

 is determined from the length of its body. The classification was 

 derived from the measurements of a large number of pups branded in 

 1912 and killed in subsequent years. The limits of the various age 

 classes are shown in the table following : 



Age classes of 7nale seals, Pribilof Islands 



Ages of seals killed on Pribilof Islands, calendar year 1930 

 [On basis of classification shown in preceding table] 



' Cows unavoidably and siccidentally killed or found dead. 



It should be stated that some of the seals recorded in the above 

 tabulation as 2-year-olds or 4-year-olds probably were 3-year-olds. 

 Not all the male seals of a given age fall within the length limits 

 assigned for the males of that age. As far as possible the killings 

 in 1930 were confined to 3-year-old males. 



RESERVING OPERATIONS 



The marking of 3-year-old male seals by shearing a patch of fur 

 from their scalps was continued in 1930 in order to provide for the 

 future breeding stock. This mark retains its prominence during and 

 for some time subsequent to the kilhng season. Since the killing 

 of fur seals at the Pribilof Islands is confined as far as possible to 

 3-year-old males, this method of marking insures protection during 

 their third year, which is the only time in their whole life when the 

 seals are subject to Idlhng. 



During the year, 4,918 3-year-old males were marked on St. Paul 

 Island and 1,621 on St. George Island, a total of 6,539. Reserving 

 operations were interrupted by the arrival of the supply ship and when 

 examination of the grounds was again made the harems had already 

 commenced to break up and there were so many cows and pups 

 mingled with the bachelor seals that it was thought advisable to 

 discontinue marking. Large numbers of unmarked 3-year-old males 

 were observed on all the hauling grounds at that time, assuring an 

 ample reserve for future breeding requirements. 



