214 



R. R. STRATY AND R. E. HAIGHT 



COMMON MURRE 



SLENDER-BILLED SHEAR- 

 WATER 



TUFTED PUFFIN 



r 







I A S " 



0; 

 ,.....,.-, 

 r^ 



9 < /! 



I I, il 



BLACK- LEGGED KITTI- i 

 WAKE 





LEGEND: Number of birds per 32.18-km segment: 

 1-5 



6-100 



101-1,000 

 1,001 + 



Sighting from land: 



Fig. 7. Distribution and numbers of birds observed in Bristol Bay along seaward migration route of sock- 

 eye salmon (from Bartonek and Gibson 1972). 



days between molts of the zoeal stages of 

 snow crabs is temperature-dependent the 

 warmer the water, the less the time between 

 molts (Ron 1970). 



Temperature, through its effects on swim- 

 ming speed, feeding activity, and growth of 

 juvenile fish, might influence the magnitude 

 of predation by birds on pelagic fish in the fol- 

 lowing ways: (1) lower sea temperatures 

 would increase the vulnerability of juvenile 

 fish to bird predation because swimming 

 speed would decrease, and the time the fish 



are of a size that could be eaten by would-be 

 predators would increase; (2) lower sea tem- 

 peratures would reduce the feeding by fish 

 and decrease the competition by fish for food 

 exploited by birds; and (3) higher sea tempera- 

 tures would have the opposite effect the 

 feeding by fish would increase consumption of 

 the foods that birds feed on. 



In the eastern Bering Sea, water tempera- 

 tures may vary greatly between years for the 

 same month (Fig. 9). Such variation should re- 

 sult in variation in the temperature-de- 



