388 



Inland Water Culture 



Studies of the food of the common sunfish, Eupomotis 

 gibbosuSjhy the senior author ('08) have shown that in 

 Old Forge Pond, when one inch in length the food is 

 predominantly entomostraca and very small midge 

 larvae. When two inches in length, it is entomostraca 

 and midge larvae of larger size, together with small may- 

 fly nymphs (Ccenis) and minute snails. When three 

 inches in length, it is grown midge larvae, mayfly nymphs 

 and caddis- worms. At this size apparently the diet of 



Fig. 231. The common sunfish. Eupomotis gibbosus. 

 (Photo by George C. Embody) 



entomostraca and small midge larvae is outgo wn, and 

 the fishes are seeking bigger game. 



At three inches in length, this fish is itself the 

 favorite food of adult bullheads. 



Excepting for a few fishes that range the open waters, 

 such as white-fish and lake herring, and that continue 

 to feed largely on plancton, there is at least one neces- 

 sary shift of diet accompanying growth; that from 

 plancton to the food of the adult. In an earlier chapter 

 (see p. 235) we have briefiy indicated the principal 

 changes of diet then occurring. 



