NOTE Yang: Diet changes of Gadus macrocephalus associated with climate changes in Pavlof Bay 



401 



Figure 1 



Location of study area in 1980, 1981, and 1995. 



100 



fish parts like head, tail, pyloric caeca, 

 etc.), and all other prey organisms not 

 included in the other eight prey catego- 

 ries. The importance of fish in the diet 

 of Pacific cod increased after 60 cm FL. 

 Walleye pollock were consumed only by 

 Pacific cod >60 cm FL. 



In general, Pacific cod ate prey of small 

 individual size (Table 2). Tanner crabs 

 iChionoecetes bairdi) ranged from 4.5 

 to 42.3 mm carapace width. Eelpouts 

 ranged in length from 36.2 to 256.6 mm 

 standard length. Other fish prey ranged 

 in length from 32.7 to 81.5 mm. Walleye 

 pollock were consumed by Pacific cod but 

 were not measurable. 



In 1995, when Pacific cod stomachs 

 were collected in Pavlof Bay, 218 wall- 

 eye pollock and 80 arrowtooth flounder 

 stomachs were also collected. Similar 

 to the results for Pacific cod, pandalid 

 shrimp and capelin were not important 

 food of walleye pollock and arrowtooth 

 flounder either (Fig. 3). These prey each 

 comprised less than 39c of the total 

 stomach content weight of walleye pol- 

 lock and arrowtooth flounder. Instead, 

 eelpouts, pricklebacks, euphausiids, and walleye pollock 

 were important food of arrowtooth flounder, and euph- 

 ausiids (83% by weight) were the main food of walleye 

 pollock. 



N=26 



40-49 



□ Polychaete 



□ Pollock 



□ Misc. fish 



□ Tanner crab 

 S Pagurid 



□ Other crab 

 El Pandalid 

 O Crangonid 



□ Misc. prey 



50-59 

 Predator fork length (cm) 



60-80 



Figure 2 



Variations in the main food items of Pacific cod, by predator size, in Pavlof 

 Bay in 1995. /i=sample size. 



Discussion 



This study shows that eelpouts 

 hermit crabs, polychaetes, and 



, Tanner crabs, crangonids, 

 echiuroids were the princi- 



