in the counts made at Amchitka. Lensink's shore counts totaled 2,903 
otters for extensive, but not complete, shoreline counts. His 
estimate of the total Amchitka otter population based on these counts 
is 6,000 to 8,000 otters. Our total count was 1,560 otters for all 
of Amchitka, and our estimate of the total number of otters there is 
2,078 to 3,120. 
. We believe that the following points clarify the differences in 
both counts and estimates: 
1. Lensink's 1956 counts were made over a period of many weeks 
in the late summer and early fall during which frequent changes in 
weather took place. It has been shown that movements of otters along 
the coast take place in response to changing weather and are perhaps 
influenced by seasonal changes that affect food resources. The pos- 
sibility is therefore suggested that otters which moved to different 
areas could have been counted more than once during the survey period. 
2. In late summer and fall, more otters (older than pups 
accompanying their mothers) would be present than in the spring, 
shortly after the period (March and April) of considerable mortality. 
3. The 1959 aerial survey showed that about twice as many otters 
were distributed around the eastern half of Amchitka as around the 
more precipitous westernhalf of the island. An aerial survey, in- 
adequate because of weather, in December 1957 revealed a similar pattern 
of distribution. The concentration of Lensink's shore counts on the 
eastern half of Amchitka would have the effect of inflating his 
estimate for the entire island. 
4. It is possible that because of the sustained high otter 
population at Amchitka over a considerable period, with attendant 
food shortages, the population has actually been somewhat reduced 
recently. 
As a result of all field work todate we believe that, if all 
adults, subadults, and pups are considered, the current otter popula- 
tion at Amchitka would not greatly exceed 4,000 individuals at the 
end of summer. 
ESTIMATES OF THE TOTAL NUMBER OF SEA OTTERS 
IN ALASKA IN 1959 
As stated in the foregoing section, we believe Mr. Lensink's 
population estimates for Alaska, other than the areas referred to, 
are adequate. In addition, Mr. Lensink (now of the Alaska Department 
of Fish and Game) told us that his recent (1959) observations in the 
Prince William Sound area confirmed his previous estimates (Lensink, 
1958). Therefore the following summary is presented: 
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