336 



U. S. BUREAU OF FISHERIES 



AVERAGE HAREM 



The estimated average harem has been determined oq the basis of 

 an increase of 8 per cent for the cows. With normal conditions pre- 

 vaiUng, the use of this rate of increase for the present will answer all 

 practical requirements. 



The average harem shows a very satisfactory decrease. This is 

 due, no doubt, to the creation of a greatly increased reserve of 

 breeding bulls. 



Computation of breeding cows, based on annual increases of 8 per cent, and of average 



harems, in 1929 



PUPS AND COWS 



This season the average rate of increase of 8 per cent, as determined 

 from complete pup counts of 1917 and 1922, has again been used for 

 computing the number of cows and pups in the herd. The number of 

 dead pups observed appeared to be about normal. The percentage 

 of dead pups as counted in 1922, therefore, has been applied to each 

 rookery. For comparative purposes only the estimated number of 

 dead pups is included in the total number of pups. 



It is possible that there has been a larger percentage of pups born 

 as a result of making a larger reserve of 3-year-old males for breeding 

 purposes. The sharp hicrease in the number of 2 and 3 year olds 

 arriving at the islands would indicate either an increase in birth rate 

 of more than 8 per cent or a sharp decrease in the mortality rate. 



