THE SEA OTTER IN THE EASTERN PACIFIC OCEAN 147 



30 fathoms or less in depth (see Diving). Where population and 

 distribution surveys were made, the area of available habitat was 

 measured on U.S. Coast and Geodetic Survey charts. A modified 

 acreage grid, 64 dots per square inch, was used to obtain measure- 

 ments which were converted to square miles of available habitat. 

 Estimates of populations (exclusive of pups carried by mothers) 

 were applied to the square miles of habitat to obtain the population 

 densities that are presented in the following discussion and tables. 



The entire Aleutian Chain, waters adjacent to the Alaska 

 Peninsula, the Sanak Islands and Sanak Reef area, the Sandman 

 Reefs, and the Shumagin Islands were surveyed one or more times 

 under good to excellent observation conditions during our com- 

 prehensive 1959, 1960, 1962, and 1965 surveys. During these 

 surveys and those by other individuals in different Alaska areas, 

 17,964 (table 19) otters were observed. The highest count obtained 

 in each area surveyed was used to obtain this total. 



As the aerial surveys and surface studies proceeded, it became 

 evident that the population of sea otters in the various geographi- 

 cally separated areas exhibited different stages of population 

 development. For example, in the Rat and Delarof Islands a 

 crowded population heavily exploited available food resources (see 

 Food and Feeding Behavior), and in certain of the Andreanof 

 Islands dense local populations were expanding into adjacent areas 

 of vacant habitat. These observations are discussed in the per- 

 spective of available data from earlier observers under the geo- 

 graphical headings that follow. 



The Near Islands 



This Aleutian group (fig. 71), the western extremity of U.S. 

 territory, is separated from Buldir, the westernmost of the Rat 

 Islands by 55 miles of open water. Attu and Agattu are the largest 

 islands but Shemya is today more important because of its airfield 

 and military base. A small military base has been maintained on 

 Attu since World War II. Early in the war, the native Aleut pop- 

 ulation was removed from Attu by the Japanese and was never 

 reestablished there (Golodoff, 1966). 



In the early years of sea otter exploitation, the Near Islands 

 yielded many furs. The Alaska survey expedition of the U.S. Navy 

 Department in 1932 searched for sea otters at Attu but found none. 

 Information was received, however, that "the Chief of the Attu 

 natives assured the commander of the expedition that there were 

 a few [sea otters] at Agattu which would soon be gone because 

 the Japanese come frequently to take them" (Hutchinson, 1935). 



