THE SEA OTTER IN THE EASTERN PACIFIC OCEAN 165 



and 1959 aerial observations indicate that the total populations 

 in these two years were at least similar, or perhaps larger in 1957, 

 since aerial counts usually include a higher percentage of animals 

 present. The number of otters seen along different parts of the 

 coast on aerial surveys when correlated with the distribution of 

 available feeding habitat around the island, indicate that the 

 distribution of otters along the shores of the entire island varies 

 according to the amount of habitat available. 



The coastal zone of sea otter habitat is narrow along much of 

 the north shore of Kanaga. In 1959, along 30 miles of the north 

 shore, we observed 415 otters (14 otters per mile of coast), while 

 along 45 miles of the mostly southern and eastern coast, where the 

 habitat zone is wider, we recorded 1,407 otters (31 per mile of 

 coast). 



These data suggest that Lensink's (1960) "somewhat conserva- 

 tive" estimate of 3,000 to 5,000 otters at Kanaga (32 to 53 otters 

 per square mile of feeding habitat) based on his sample count 

 along the south shore may have been quite realistic (table 27). 



Adak Island. — The U.S. Naval Station, Adak, was established in 

 the early 1940's. It remains today the most important center of 

 human population in the Aleutian Islands and furnished facilities 

 for sea otter studies in the outer Aleutian area. 



The Murie expeditions did not find sea otters at Adak and ob- 

 tained no information from natives that they were observed there 

 in recent years (Williams, 1937). 



Although 14 otters were seen in 7-mile-wide Adak Strait between 

 Kanaga and Adak in 1943 (Lensink, 1960), few if any crossed the 

 strait and became established at Adak during the 1940's. 



When I visited Adak on 31 October to 5 November 1947, I saw 

 no sea otters and could find no report of an observation there. 

 Neither did R. D. Jones see any otters (table 28) on a complete 

 circuit of Adak by dory in 1952. The first indication that sea otters 

 had become established at Adak was an observation of 48 animals 

 during an aerial survey in 1954 by Lensink (1960). 



The influx of otters that began from Kanaga to Adak in the early 

 1950's proceeded rapidly and was documented during the 1959 and 

 1962 aerial surveys. It appears that emigration from Kanaga (26 

 otters per square mile in 1959) to Adak (31 otters per square mile 

 in 1959) continued during this period and that a large population 

 at Kanaga during a period of years had depleted food resources 

 there. Adak, on the other hand, was repopulated only recently 

 (in 1959) and serious food depletion did not occur until the 



