THE SEA OTTER IN THE EASTERN PACIFIC OCEAN 69 



light-colored objects seen on the chest of some of these animals 

 were food items. 



Aerial observations of most of the Alaskan areas populated by 

 sea otters indicate that otters prefer to feed in depths of 5 to 15 

 fathoms and that most of them, except off Unimak Island, are 

 within about one-half mile of the shore. Weather conditions and 

 lack of time prevented aerial examination of all shallow banks 

 far from land where otters might be expected. On 3 May 1965, 

 however, Tahoma Reef (51°51' N. lat, 175°50' E. long.). Middle 

 Reef (52° N. lat, 176° E. long.), and Buldir Reef (52°10' N. lat., 

 176°30' E. long.), respectively, 30, 20, and 20 miles from the 

 nearest land (Buldir Island) and having considerable water areas 

 from 3 to 20 fathoms in depth, were examined. Observation con- 

 ditions were excellent. We saw a number of birds and sea lions, 

 particularly in the kelp beds over Tahoma Reef, but sea otters 

 were absent. 



Numerous observations of feeding otters near Amchitka Island, 

 at all seasons, indicate a preference there for depths of 5 to 20 

 fathoms. Also, during rough winter weather otters are inclined 

 to search for food to a greater degree near shore. When the 

 weather is mild they tend to move offshore to the vicinity of sub- 

 merged reefs. 



Several otters were observed over deep water and far from 

 shore in the vicinity of drifting patches of floating kelp. This 

 suggests that the otters could obtain food organisms that gathered 

 in the shelter of the kelp. It is known that pelagic fishes accumu- 

 late under and around floating objects in the sea. That sea otters 

 might rarely adapt to pelagic feeding is intimated by Snow (1910, 

 p. 280) : 



On one occasion I found the stomach of an otter I killed some 8 or 10 miles 

 offshore filled with the remains of a quantity of small fish with no signs of 

 the remains of any crustaceans. 



He does not, however, identify the area or state the depth of 

 water where this otter was taken. Marakov (1965, p. 214) also 

 reports sea otters up to **15 miles from the coast in comparatively 

 deep places." No authentic record, however, indicates that the sea 

 otter is capable of adapting itself to the capture of pelagic organ- 

 isms where great depth prevents food gathering from the bottom. 



In consideration of all the data available, it is my conclusion 

 that sea otters feed in shallow water (1 to 15 fathoms deep) when 

 sufficient food is available there. When food resources are more 

 abundant offshore and particularly in mild weather, they move to 

 feed in depths of 20 or, rarely, 30 fathoms. Food dives to depths 



