NOTE Hunt et al.: Oceanic feeding habits of Oncorhynchus tshawytscha 



721 



found rockfishes not to be a major prey item of 

 chinook salmon, northern anchovy were in fact com- 

 monly taken. In addition, the importance of Pacific 

 herring and Pacific sandlance was substantial. The 

 occurrence of invertebrate prey items (euphausiids, 

 crab megalopae, and squid) during spring months 

 agrees with studies conducted both to the south 

 (Merkel, 1957) and north (Reid, 1961; Prakash, 1962; 

 Brodeur et al., 1987 ) of the region of our study. Merkel 

 ( 1957 ) commonly found euphausiids and squid, April 

 through June, and crab megalopae (presumed to be 

 Cancer magister). March through May, in stomachs 

 of fish caught off San Francisco. Similarly, Brodeur 

 et al. (1987), in coastal waters off Oregon and Wash- 

 ington, and Prakash (1962), in British Columbian 

 waters, found euphausiids to be a major prey item 

 during the months of May and June. Prakash also 

 observed an abundance of crab megalopae in chinook 

 diet during June. Squid were a dominant prey item 

 one year in Reid's study off southeastern Alaska dur- 

 ing late spring. These results and the great impor- 

 tance of euphausiids, crab megalopae, and squid in 

 our study (Fig. 2) confirm the importance of inverte- 

 brate prey, in some years, to chinook salmon. 



Acknowledgments 



Financial support for this research was provided by 

 the U.S. National Marine Fisheries Service. An ear- 

 lier version of this manuscript was critically reviewed 

 by R. D. Brodeur. 



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