DURBIN ET AL.: STOMACH CONTENTS OF HAKE AND COD 



portant in the diet up to a size of about 40 cm; hake 

 >40 cm fed almost exclusively on fish. The mean 

 weight offish prey" exceeded that of "other prey" in 

 all silver hake size classes >30 cm during spring, and 

 >20 cm during fall (Table 3). 



In contrast to silver hake, Atlantic cod in all size 

 classes fed on "other prey" to a significant degree. 

 Fish prey was absent from the diet of cod <30 

 cm during the spring, but was observed in all size 

 classes in the fall (Table 4). Fish prey constituted a 

 significant portion of the diet in cod >60 cm during 

 spring, and >30 cm during fall, but the mean weight 

 offish prey did not exceed that of other prey except in 

 cod >70 cm (spring) or >50 cm (fall). 



The total weight of food as a percentage of body 

 weight was significantly greater (P < 0.05) in the 

 hake than in the cod during both the spring 

 and the fall (Table 5). During spring, hake contained 

 significantly more fish prey (% BW) than cod, but the 

 amount of "other" prey was not significantly dif- 

 ferent (P < 0.05) (Table 5). During the fall, the 

 amount of fish prey was not significantly different, 

 but hake contained significantly more "other" prey 

 than cod. 



The mean stomach content weight as a percentage 

 of body weight of the large silver hake was significant- 

 ly greater (P < 0.05) than the small silver hake during 

 spring, while during the fall the stomach content 



weight of the small hake was greater. During both 

 seasons, large hake contained significantly (P< 0.05) 

 more fish prey than the small hake (Table 5); the 

 large hake contained 66.2 and 77.39? fish prey as a 

 percentage of body weight during spring and fall, re- 

 spectively, and the small hake 18.7 and 8.5%, 

 respectively. 



Fish prey constituted and 32.1% of the stomach 

 contents of small Atlantic cod, and 37.4 and 55.1% of 

 the stomach contents of large Atlantic cod during 

 spring and fall, respectively. During spring, small cod 

 contained a lower mean stomach content, as a per- 

 centage of body weight, than large cod (Table 5) . This 

 was due to the lack offish prey in the diet of small cod, 

 since the amount of food in the "other" category did 

 not differ significantly between the two size classes. 

 During fall, the mean stomach contents (total, fish 

 and "other" prey) as a percentage of body weight did 

 not differ (P < 0.05) between the two size classes 

 of cod. 



The mean weight of food in the stomachs of each 

 group of fish did not exceed 1.0% BW (body weight), 

 but the range of values observed in individual fish ex- 

 tended from to 23.7% (Table 5). In general, the 

 maximum observed values for the fish prey category 

 were larger than those for the other prey category (es- 

 pecially in Atlantic cod). Among silver hake, the max- 

 imum values for large fish were greater than for small 



TABLE 5. — Overall mean and 95% confidence limits, minimum and maximum values, and median stomach 

 contents of the different categories of silver hake and Atlantic cod. BW = body weight. 



Stomach contents, all fish including those 

 with empty stomachs 



Stomach contents, excluding fish 

 with empty stomachs 



443 



