FISHERY BULLETIN: VOL. 82, NO. 2 



TABLE 10. — Overlap matrix for the five species of Sebastes. 

 Only those prey that have proportional abundances exceeding 

 V , were used in the analysis. Values above the rules are for 

 proportional weight overlap and values below are for propor- 

 tional abundance. The mean overlap for each species by weight 

 and number is given in parentheses directly above and below 

 the rules. 



diet of this species than any of the other rockfish. 

 Decapods were of moderate importance to S. 

 diploproa and, to a lesser extent, S. alutus. Fishes 

 were an important food source by weight for all 

 rockfishes but S. alutus. 



Seasonal Variation 



Differences in the diet of S. pinniger and S. 

 flavidus are summarized in Table 11 for the four 

 seasons. The spring cruise shows an extreme dom- 

 inance of one prey item, Euphausia pacifica , in the 

 diet of S. pinniger. This prey species was found in 

 about three-quarters of the stomachs and made up 

 almost all the prey biomass. Decapod shrimp and 

 fishes were rarely found in the diet at this time. 

 Euphausiids also dominated the diet in the sum- 



100-,-= 



90- 



80- 



70- 



m 



i 60. 



50- 



« 40-| 



r- 

 z 



Ld 



g 30. 



Ld 

 Q- 



20-1 



10- 





S . pinniger 

 S . f lavidus 

 S . diploproa 

 S crameri 

 S . alutus 



EUPHAUSIIDS DECAPODS AMPHIPODS COPEPODS 



PRINCIPAL PREY ITEMS 



FISHES 



FIGURE 4. — The proportions of the five major prey taxa found in the five rockfish species based on numerical composition. 



280 



