THE SEA OTTER IN THE EASTERN PACIFIC OCEAN 145 



Figure 70. — Part of a group of 440 sea otters in Kujulik Bay on the south 

 shore of the Alaska Peninsula. This was the largest group observed on the 

 aerial surveys. Flight altitude 200 feet, air speed 120 knots; 10 April 1962. 

 (KWK 62-39-13) 



of animals were seen; most animals were scattered. Because it 

 is easier to see a large group of animals than scattered individuals, 

 we realized that, in our aerial surveys, we saw a greater proportion 

 of the animals where populations were dense than where they 

 were sparse. For this reason, a sliding scale based on numerous 

 field observations was chosen to compute an estimate of total 

 populations in various areas. 



Otters counted Estimation factor to obtain total 



1-15 Estimate 50 percent were seen 



16-100 Estimate 60 percent were seen 



Over 100 Estimate 75 percent were seen 



Aerial photography 



Aerial photography is a useful censusing tool when views of 

 animal concentrations may be obtained. A large majority of sea 

 otters are scattered as individuals or gathered in small groups of 

 5 to 20 animals, which may be counted directly. Therefore we 

 have used aerial photographs primarily to assist us in improving 

 our technique of estimating occasional large concentrations of 

 otters. The mean of 1962 and 1965 data listed below shows that 



