DURBIN ET AL.: STOMACH CONTENTS OF HAKE AND COD 



lower than in the present study, declining from 1.3% 

 BW/d in a 40 cm cod to 0.8% BW/d in a 60 cm fish, to 

 0.5% BW/d in a 100 cm fish. 



Grosslein et al. (1980) used energy budget 

 calculations to estimate the daily ration of six major 

 fishes (Atlantic cod, silver hake, yellowtail flounder, 

 haddock, herring, and mackerel) in the northwest 

 Atlantic during 1963-72. The mean daily ration of 

 silver hake was calculated to be 1.3% BW/d; the daily 

 ration of Atlantic cod was 0.9% BW/d. During 1963- 

 72, the daily food consumption by hake averaged 

 24.2% of the total consumption by the six species; the 

 daily ration of the cod was 3.7% of the total. 



A study by Edwards and Bowman (1979) estimated 

 the daily ration of silver hake to be 3.1% BW/d, and 

 Atlantic cod to be 2.3% BW/d. These authors also 

 concluded that the hake is a major consumer in the 

 food web of the northwest Atlantic. 



These daily ration estimates compare with mean 

 upper and lower estimates of 3.2 and 2. 9% BW/d for 

 silver hake <20 cm, 2.2 and 0.8% BW/d for hake >20 

 cm, and 1.5 and 0.9% BW/d for Atlantic cod >30 cm 

 in the present study (Table 8, assigning spring and 

 fall. estimates equal weight for the determination of 

 mean ingestion). 



Differences in the estimates of daily ration in the 

 above studies reflect differences in the mean 

 stomach content weight of the fish, as well as dif- 

 ferences in the methods used to estimate daily ration. 

 However, estimates of daily ration in silver hake were 

 consistently found to be greater than in the 

 Atlantic cod. 



The high proportion of empty stomachs among 

 silver hake, and the fact that the average amount of 

 food in the stomachs of both silver hake and Atlantic 

 cod were small, is intriguing from an ecological view- 

 point. For example, the results may simply reflect the 

 innate feeding behavior of these two predators, i.e., 

 they feed at a modest rate even when food is plentiful 

 and easily obtained. On the other hand, the results 

 could mean that food is either scarce, or if abundant, 

 difficult for the fish to locate or capture. It would be of 

 interest, in future work, to explore the question of 

 whether the major fish predators in the northwestern 

 Atlantic are food limited, since this will greatly affect 

 the importance of different predator-prey links in the 

 food web and the intensity of competition among dif- 

 ferent fishes for food. 



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