Otters Estimate of total 
Date Area counted otters in area 1/ 
27 May Seguam 14 19 - 28 
"oo Amukta 8) ole 0 
" " Chagu lak 'e) oO - 0 
" " Yunaska oO e) - 0 
Total 14 19 - 28 
Islands of the Four Mountains 
27 May Herbert Oo 0 - 0 
Total all areas 9,507 12,665 - 19,014 

1/ Considering that 25 to 50 percent of the otters were not seen. 
SURVEYS IN OTHER ALASKAN AREAS BEFORE 1959 
Between 6 May and 28 September 1957, Calvin J. Lensink, then a 
graduate student at Purdue University and a temporary employee of the 
Fish and Wildlife Service, conducted a sea otter population survey 
which included Kodiak Island, the south coast of the Alaska Peninsula, 
its offshore islands, and limited areas among the easternmost Aleutians. 
In addition, Lensink made shore counts at Amchitka in 1956, and dory 
and partial aerial counts at Adak and Kanaga in 1957. He was assisted 
by a number of Fish and Wildlife Service employees. Using his field 
counts and miscellaneous counts and estimates from many sources, which 
cover a period of many years, he presented population estimates of 
31,850 to 49,750 sea otters in all areas of Alaska. Of this total, 
the majority (24,825 to 40,950) were considered to be in the Rat, 
Delarof, and Andreanof Island groups from which only fragmentary 
information of recent origin was available. 
We feel that Lensink's population estimates for the areas which 
he surveyed with care in 1957 are adequate. However, the results of 
our 1959 surveys indicate to us that for the areas which he did not 
survey his estimates were optimistic. It has been shown that calcula- 
tions of marine mammal populations based on other than carefully 
gathered current field data are liable to be in considerable error 
(Kenyon et al., 1953). 
The most apparent conflict between the basic information gathered 
by Lensink in 1956 and that gathered during our 1959 aerial surveys is 

* tLensink, C. J.: Report on sea otter surveys, 6 May to 28 September 
1957. U.S. Dept. Interior, Fish and Wildlife Service, Report 
submitted 4 April 1958, 61 p. 
