102 ALASKA FISHERIES AND FUR INDUSTRIES IN 1917. 



large increase in the percentage and again in 1917. This, however, 

 was foreseen by all students of the subject. With an increase of bulla 

 and the reduction of the average harem there must of necessity be an 

 increase in the dead and injured cows in the harems. 



The increased death rate of ])ups, due to the increase of bulls in 

 1916, can not be felt as a decrease of births until 1919 and should be 

 most noticeable in 1920 when the results of the minimum average 

 harem of 1917 will show. The increased death rate of pups on land 

 due to any cause is certain to .^ how as a decrease in births three years 

 later. Of course the large size of the herd might make it almost 

 imperceptible in a single year, when complete rookery observations 

 are impossible, but the results are there and cumulative and can not 

 be ignored. 



During the count careful lookout was kept for signs of mange, un- 

 cinaria, etc. The mange appeared in 1914 to a noticeable extent, 

 reached a maximum in 1915, and has gi^own less and less since. At 

 the present time no serious trouble can be foreseen from this source 

 because the percentage of seals afflicted is neghgible. Mange afi'ects 

 the adults as well as the 5'oung and usually appears as round spots on 

 the back. Here the guard hairs fall out, exposing the light-brown 

 underfur. Such spots have been known to the trade as "rubbed 

 places," but no rubbing action, such as would produce them,' is possi- 

 ble by the fur seal. 



As a result of the counting done two pups, both on St. Paul, were 

 lost. One was smothered in a pod and the other was killed by a bull. 



DEAD PUPS. 



The increase in the percentage of dead pups keeps pace with the re- 

 duction of the average harem and the increase of bulls. As the bulls 

 increase and get closer together on the rookery areas, there is more fight- 

 ing and charging back and forth over the pups so that the number of 

 dead will increase proportionately. Thus it has now become 3.01 

 per cent of the total, whereas it was under 2 per cent in 1914, when the 

 average harem was treble what is found on many rookeries at present. 



Still no very alarming results can be foreseen from the present 

 death rate on land, Of course the loss of females is cumulative and 

 important for that reason. By keeping the average harem at a mini- 

 mum, and it has doubtless been close to that in 1917, the loss of pups 

 due to the trampling of the bulls can not be expected to go much, if 

 any, over 3 per cent. 



This loss is under the control of man. He can make it 3 per cent 

 or 2 per cent as he chooses by the simple expedient of controlling the 

 number of males; that is, by increasing the average harem. It can 

 not be done in a year, nor as the herd exists at present, in several 

 years. But after the surplus piled up during the six seasons of 

 closely restricted killings shall have become eliminated and the cur- 

 rent quotas of killables are utilized systematically, there seems to be 

 no obstacle in the way of keeping the average harem the. size most 

 desirable. 



