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R. R. STRATY AND R. E. HAIGHT 



Table 4. Food items eaten by the adult stage of seven commercially important species offish in 



the eastern Bering Sea. 



Table 5. Forage fish and invertebrate foods eaten by seven species of marine birds in the eastern 



Bering Sea. 



Food item 



Shearwaters Murres Puffins Murrelets Fulmars Kittiwakes Gulls 



from copepods near the surface to euphausiids 

 at mid-depths and near the bottom. Euphau- 

 siids are large and abundant zooplankters 

 which, for the most part, are available only to 

 deep-diving birds. Adult pollock also consume 

 herring, sand lance, capelin, and other small 

 fish. 



Both marine birds and fish are capable of 

 exploiting a wide variety of food, and often 

 their stomach contents reflect the relative 

 abundance of food items in the area. Ogi and 

 Tsujita (1973) illustrated the differences in 

 the food taken by murres captured at dif- 

 ferent locations in the eastern Bering Sea. 

 Carlson (1977) and Ogi and Tsujita (1973) re- 

 ported on differences in the diet of juvenile 

 sockeye salmon captured at various locations 



in Bristol Bay and the eastern Bering Sea. 

 The diets of many species of birds and fish, 

 however, seem to be largely determined by 

 their physiological and morphological adapta- 

 tions and resultant feeding behavior. For in- 

 stance, adult sockeye and pink salmon have 

 well-developed gill rakers and feed largely on 

 zooplankton, whereas chinook and coho sal- 

 mon have poorly developed gill rakers and 

 feed almost entirely on fish. In the eastern 

 Bering Sea, murres appear to prefer the 

 Pacific sand lance, whereas the slender-billed 

 shearwater consumes mainly euphausiids (Ogi 

 and Tsujita 1973). Thus, murres may be 

 greater competitors with piscivorous fish 

 than are shearwaters. Shearwaters are prob- 

 ably more important as competitors with zoo- 



