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



719 



northern anchovy {49'7c). Pacific herring (19^7^), Pa- 

 cific saury ( 17% ), and night smelt ( lOVc ) dominate in 

 late summer. 



Discussion 



The feeding habits of northern California chinook 

 salmon varied between years and season. This re- 

 sult is consistent with previous studies. Petrovich 

 (1970) found northern anchovy, euphausiids, Pacific 

 herring, osmerids, and rockfishes to be the most im- 

 portant prey items in coastal waters off Humboldt 

 Bay and Trinidad Bay in 1960-1964. As in our study, 

 crab megalopae were especially abundant in one year 

 In contrast to our results, Petrovich reported rock- 

 fishes to be present in 13% of all stomachs from 1960 

 to 1964, and in terms of frequency of occurrence they 



ranked third to northern anchovy and euphausiids. 

 We encountered only 45 juvenile rockfishes during 

 our study, all of which came from seven stomachs in 

 the spring of 1994, representing only 2% of all stom- 

 achs examined. 



Petrovich found relatively few Pacific sandlance 

 and squid, and no Pacific saury in salmon stomachs 

 that he examined. Our study shows that each of these 

 food items contributes significantly to the diet of 

 chinook salmon off Northern California (Fig. 2). Pa- 

 cific sandlance, although absent in 1995 and only 

 present in small numbers during late spring of 1994, 

 were the major food source (707=22%) in late sum- 

 mer of 1994. Squid were present in late spring and 

 late summer of both years and greatly outranked 

 (707=45% ) all prey items in late spring 1995. Pacific 

 saury were present in stomachs collected during late 

 summer 1994 (707=8%) and late summer 1995 



