CALKINS: FEEDING BEHAVIOR OF ENHYDRA I.VTRIS 



Table 4. — Qualitative comparison of food of sea otters in Montague Strait, Alaska. 



and Montague Strait with molluscs second in the 

 Aleutians and echinoderms second at Point Lobos, 

 Calif. 



Sea urchins seem to be a relatively minor part of 

 the diet in Montague Strait. No living sea urchins 

 were found in the intertidal zone and only an occa- 

 sional test was found. Kenyon (1969:111) indi- 

 cated that "the bones of those sea otters utilizing 

 sea urchins . . . are stained purple by the bio- 

 chrome polyhydroxynaphthoquinone ( Scott in Fox 

 1953)."' Of the six different sets of skeletal remains 

 found on the beaches of Montague Strait during 

 this study, none showed this diagnostic purple 

 stain. Schneider (Alaska Department of Fish and 

 Game, pers. commun.) reports that of the several 

 skulls he obtained from Prince William Sound, 

 none show purple pigmentation. 



Fishes are an important food source in the Aleu- 

 tians when invertebrates become depleted. Ken- 

 yon (1969:110) reported that "At Amchitka it 

 appears that the otters fall into two groups — those 

 eating mostly fish and those eating mostly in- 

 vertebrates." Otters were not observed eating 

 fishes in Montague Strait and fishes are probably 

 not important here. During the latter part of this 

 study pink salmon, Oncorhynchus gorbuscha, and 

 chum salmon, Oncorhynchus keta, became abun- 

 dant. Vania^ found that otters captured in Mon- 

 tague Strait and held for translocation refused to 

 eat chum and pink salmon for a period of 24 h. 



^Vania, J. 1967. Sea otter. /« Marine mammal investigations. 

 Alaska Dep. Fish Game, Vol. 7 Annual Project Segment Rep., 

 Fed. Aid Wildl. Restoration, Proj. W-14-R-1 and -2, work plan G, 

 p. 6-13. 



129 



