720 



MARINE PRODUCTS OF COMMERCE 



delivery to Canada of 20 per cent of the skins taken on the Pribilof Islands, the 

 remainder to be retained by the United States. 



The international cooperation afforded by the treaty of 1911 and the provisional 

 agreement of 1942 has resulted in the most outstanding of all accomplishments in 

 the conservation of wildlife. Since 1911 the herd has steadily increased. In this 



{Courtesy U. S. Fish and Wildlife Service) 



Fig. 34-2. A small family of fur seals, St. Paul Island, Alaska. 



period more than 1,500,000 seals have been killed for their fur. This almost 

 phenomenal growth was possible through careful management, taking into con- 

 sideration all phases of the fur seal's natural history. Were it not for the polyg- 

 amous nature of fur seals, the birth of both sexes in equal numbers, and the 

 early maturity of the females, the herd would still be of almost insignificant size. 



The convention of 1911, during the 30 years it was in effect, afforded protec- 

 tion to the Robben Island herd, then under the jurisdiction of Japan, and the 

 Commander Islands herd belonging to Russia. In 1945 the Robben Island herd 

 was estimated to contain 60,000 seals and the Commander Islands herd, 56,000. 

 Prior to World War II land killings by Japanese authorities on Robben Island 

 totalled 2,000 to 3,000 animals annually. 



Natural History. The Alaska fur-seal herd spends 4 to 6 months during the 

 summer and fall of each year on the Pribilof Islands and in adjacent waters. 

 The remainder of the time is spent at sea; seldom do they appear ashore at any 

 other place. The first animals to arrive at the Pribilof s in the spring are the mature 

 bulls. These take up strategic positions along the beach where they await the 

 arrival of the cows. The younger, less experienced bulls are forced to take less 

 advantageous positions at the rear of the rookery areas. During this period there 

 is constant bellowing of competing animals, but there is little real fighting. The 

 cows commence to arrive early in June and harems of 75 to 100 cows for each bull 

 are formed. Soon after coming ashore each cow gives birth to one pup weighing 

 about 12 pounds. Breeding takes place soon after the young are born, the period 



