120 ALASKA FISHERIES AND FUR INDUSTRIES IN 1917. 



2-YEAR-OLDS, MALE AND FEMALE. 



The number of pups born in 1915 furnishes the basis for detei min- 

 ing the number of this class at the present time; this was 103,527. 

 The computations leading up to 1916 for this and subsequent classes 

 have been published in previous reports of the Bureau of Fisheries 

 and need not be repeated here. Thus there were computed 33,646 

 female yearlings in 1916, 20 per cent are supposed to have died the 

 second winter, leaving 26,917 virgin cows in 1917. 



There were estimated 33,645 yearlings males for 1916. One was 

 killed in the fall which left 33,644. Deduct the 20 per cent for natural 

 mortality and there remain 26,915 at the beginning at 1917. An 

 even hundred were killed as 2-year-olds, which leaves 26,815 for the 

 class on August 10, 1917. 



3-YEAR-OLD MALES. 



The number of 3-year-old males is derived from the births of 1914, 

 or in other words, from the 2-year-olds in 1916. The latter figure was 

 24,169. Of these 136 were killed in the fall of 1916, leaving 24,033. 

 Deduct 4 per cent for natural mortality and there remain 23,072 for 

 the beginning of 1917. During the past summer (1917) 3,565 were 

 killed, so that there should remain on August 10, 19,507. 



The 3-year-old females bore pups for the first time in 1917 and are 

 therefore included in the breeding-cow class. 



4-YEAR-OLD MALES. 



The number of 4-year-old males is derived from the number of 

 births of 1913 or the 3-year-olds in 1916. The 3-year-olds in 1916 

 numbered 19,402. As explained heretofore no deductions need be 

 made for natural mortality of bachelors after the third year. There- 

 fore, we need only deduct the number of animals killed on land in the 

 regular course of events. In the fall of 1916 and the summer of 1917 

 there, were taken of the 3-year-olds and 4-year-olds, respectively, 786 

 and 1,985. Deduct these numbers and there remain 16,631. 



5-YEAR-OLD MALES. 



This category is derived from the pups born in 1912 or the 4-year- 

 olds of 1916. The latter figure was 15,427. Deduct 151 4-year-olds 

 killed in the fall of 1916, and 463 5-year-olds killed in the summer 

 of 1917, and there remain 14,813. 



6-YEAR-OLD MALES. ' 



The number of 5-year-olds computed for 1916 was 15,494. Three 

 were killed that fall leaving 15,491, and 94 6-year-olds, or over, were 

 taken in the summer of 1917. Some of these were known to have been 

 over 6 years old, but as the limits of this age are not yet defined and 

 the number concerned is insignificant it may be deducted from the 

 class. This leaves 15,397 to enter the surplus and idle-bull classes in 

 1918. After the age of 6 years is reached it is very probable that the 



