period on the surface eating. Thus it is possible that at any given 
moment 75 percent of the otters in an area could be seen. In practice 
it is unlikely that this high a percentage would be seen. 
After considering the sample counts in comparison with the aerial 
counts and in view of other considerations as presented above, it was 
concluded that for the purpose of obtaining an estimate of the popula- 
tion of sea otters in the outer Aleutians, between 50 percent and 75 
percent of the otters were counted. 
Results of the survey are presented graphically on the map on 
page iv. 
