Turner and Kraats. — Food of Large-Mouth Bass 379 



it grows larger and swifter, it takes larger and more active 

 animals for food. If an animal be of suitable size the only- 

 limitation to its use as food is its relative abundance and 

 there is little or no choice indicated for any particular animal 

 of the suitable size as long as it is active. This is the most 

 simple explanation. It does not seem necessary to invoke any 

 other complicating factors such as changes in habit, migration, 

 or definite selection on the part of the young bass. 



A comparison of the food cycles of the young large-mouth 

 with that of the young small-mouth bass is of interest, owing 

 to differences in their general habits, causing minor differences 

 in their food cycles. The predominance of Entomostraca and 

 midge larvae in the food of the very young is common to both 

 species. In the next stage the small-mouth bass turns imme- 

 diately to other insect larvae, while the large-mouth bass takes 

 amphipods principally. This is to be accounted for by the 

 fact that the large-mouth bass frequents quiet waters where 

 masses of submerged vegetation afford feeding grounds for 

 innumerable amphipods, while the small-mouth bass is to be 

 found in waters freer of vegetation, and where insect larvae 

 probably supplant the amphipods. Both species take fish 

 and large insect larvae principally during the late summer, but 

 the small-mouth bass becomes definitely piscivorous at an 

 earlier age than the large-mouth, the former at 12 mm. and 

 the latter at 35 mm. It is probable that the small-mouth 

 takes up the fish-eating habit earlier because of the lack of 

 other food of suitable size. Crayfish also play a larger part 

 in the food of the small-mouth, which is naturally to be ex- 

 pected in view of the fact that the small-mouth bass and the 

 crayfish both abound in the same habitat. 



SUMMARY 



1. The food of the young large-mouth black bass under- 

 goes two rather definite changes between the 10 and 85 mm. 

 stages. 



