70 



BULLETIN OF THE BUREAU OF FISHERIES. 

 SUMMARY OF MEASUREMENTS. 



In view of the foregoing, it is evident that bachelor seals of various ages can be 

 distinguished with a high degree of accuracy; that the difiference between them is best 

 expressed in the total length of the animal taken before it is sldnned; and that weights, 

 either of animals or of skins carrying varying amounts of blubber, are unreliable as a 

 criterion for age. As stated elsewhere, therefore, it is desirable that the classification 

 of seals killed be made upon the basis of measurement rather than weight. It should 

 be said, also, that the native clubbers are able to distinguish seals of different ages 

 with very few exceptions, and that a system of measurement in the field would tend 

 to increase their efficiency and reduce their mistakes to a minimum. The measurements 

 made in 1914 may be subject to slight revision with further experience and practice, 

 but in general it seems safe to state that, with possible rare exceptions, yearhngs have a 

 body length between 34 and 37 inches; 2-year-olds between 37 and 43 inches; 3-year-olds 

 between 43 and 52 inches, and 4-year-olds between 52 and 59 inches. The data on the 

 several classes are summarized below: 



Condensed measurements of young males. 



Age. 



Yearlings . 

 a-year-olds 

 3-year-olds 

 4-yearK)lds 



Average 



body 



length in 



inches. 



3S-h 

 401 

 48 

 5Sl^ 



Extremes 

 of body 



length in 

 inches. 



Average 



length of 



skull in 



millimeters. 



34i-37 

 36i-43i 



45i-S2l 

 52 -S8 



Extremes 

 of length of 



skull in 

 millimeters. 



175-3 

 192 

 205. 2 



170-1S1 

 182-198 

 202-20S 



Number 

 measured. 



5 

 13 



35 

 5 



MORTALITY OF SEAl^. 



DEATH OF PUPS ON LAND. 



In making the pup count between July 29 and August 5, the number of dead pups, 

 as well as of live ones, was regularly recorded. When the rookeries were on a narrow 

 stretch of beach, the dead pups were enumerated as they were passed over in counting 

 the live ones. Where the rookeries spread out over extensive areas, however, these 

 areas were examined for dead pups after the live ones had been counted. In the follow- 

 ing table are given the total numbers of pups, the numbers of dead pups, and the per- 

 centages of dead pups in 19 14 for each rookery on the two islands as ascertained at the 

 time of the count of pups, July 29 to August 5. 



