NOTES OX THE FOOD OF THE YELLOAV PERCH IX 

 CAYUGA LAKE. 



W. A. HOFFMAN. 



The intention of the Avriter at the time this study was begun, 

 was to make a careful examination of the stomach contents of 

 the yellow perch, Perca flavescens (Mitchill), in its various ages 

 and during- the different seasons of the year. For various rea- 

 sons this program could not be carried out at the time, and no 

 opportunity has been found since. 



M'ost of the w^ork was done during the summer of 1915, in 

 the limnological laboratory of the Department of Entomolo,g\' at 

 Cornell University. The fish, twenty-one in number, were seined 

 in the southern end of Lake Cayuga, a narrow glaciated body 

 of water approximately^ forty miles in length, situated in the 

 central portion of New York state. Hauls were made on two 

 days, Jnne 25, and July 14, the majority of the specimens hav- 

 ing been taken on the latter date. 



As soon as the peroh were killed, a slit was made anterior of 

 the anal fin. Then further action of the digestive juices upon 

 the food was prevented by placing the fish in an 8 per cent 

 solution of formaldehyde. Following this the stomach contents 

 were removed into a watch glass, and the various elements then 

 sorted into similar containers. In most cases the food which 

 had reached the small intestine was too decomposed to permit 

 accurate identification. 



After these preliminary steps the contency were examined 

 under the binocular or compound microscope for identification. 

 The length of all fish examined was from th^ tip of the snout 

 to the base of the caudal fin. 



Nematodes, Cestodes, Trematodes and Acanthocephala were 

 found among the stomach contents but were not included in the 

 count since they are parasitic ajid can not be regarded as food 

 In a few cases some small Crustacea were found that were prol>- 

 ably taicen in accidentally, or were obtained secondarily fron:- 

 prey the fish had caught. The following indicates the stomach 

 contents in detail : 



