THE SEA OTTER IN THE EASTERN PACIFIC OCEAN 177 



Table 32. — Numbers of sea otters observed and estimated population in the 



Shumagin Islands 





Aerial survey 



1962 



Island 







estimate 





1957 1 



1962 2 



of total 



Unga 



2 



4 



8 



Nagai- - — . 



149 



338 



676 





3 



14 



28 





160 



38 



76 



Chernabura 



132 



79 



158 



Simeonof 



455 



294 



588 



Little Koniuji 



430 



255 

 222 



510 

 444 



Big Koniuji 



220 



Peninsula .... ... 



0 



3 



6 



Spectacle, Bendel, and Turner . . 



268 



105 



210 



Popof ( plus rocks ) ._ 



2 





4 



Andronica... 



1 





2 





7 





14 



Total... 



... 1,829 



1,352 



2,724 



1 Complete aerial survey, 20 to 24 July 1957 (Lensink, 1958). 



2 Aerial survey, 10 April 1962, by D. L. Spencer and Kenyon. The survey of shallow areas 

 offshore was incomplete. Therefore all 1962 field enumerations are increased by a factor of 50 

 percent to obtain the estimated total. If Lensink's 1957 count is used, the estimated total in 

 that year is 2,440 (assuming 75 percent were seen). If population growth is considered to be 

 5 percent per year the 1962 population was 3,045 otters based on Lensink's field count. 



between Chernabura and Simeonof Island, furnish sea otter 

 habitat well offshore. 



Surface observations at Simeonof Island between 4 and 10 

 June 1960 did not give an adequate indication of the number of 

 sea otters inhabiting this area. On 8 June a dory survey around 

 Simeonof Island yielded a count of only 75 adult otters. 



When the aerial observations of 1957 and 1962 are compared 

 (table 32) it appears that many of the 1962 counts are sub- 

 stantially less than those obtained in 1957 (Lensink, 1958). I 

 believe that, because of the very calm weather conditions pre- 

 vailing before and during the 1962 survey, many otters had moved 

 to shallow offshore feeding areas, as they were observed to do in 

 June 1960, and were thus not seen. Lack of time prevented a 

 comprehensive survey in 1962 of rather large offshore shallow 

 areas. 



U.S. Coast and Geodetic survey charts indicate that water depth 

 is not known in much of the Shumagin Islands area. A careful 

 measurement of available sea otter habitat could therefore not 

 be made. The available soundings suggest that large shallow areas 

 exist. I have estimated that about 700 square miles of habitat are 

 available around the islands and that in 1962 the population 

 density was about four otters per square mile of habitat. 



A laska Peninsula 



The south shore of the Alaska Peninsula, which offers con- 

 siderable sea otter habitat, extends for over 400 miles from False 



I 



