Mar., 1920] Food and Fish Associates of Yomig Perch 149 



In an examination of six very young perch he finds the food 

 to consist almost wholly of entomostraca, cladocera and cope- 

 pods being in about equal quantities, and a few minute midge 

 larvae. 



Hankinson (1908) finds that the stomachs of a few fry (of 

 perch) contain chiefly entomostraca. 



Hankinson (1916) finds the stomachs of perch from one to 

 one and a half inches in length to contain only cy clops and 

 diaptomus. 



Pearse (1918) finds that the perch is in general a versatile 

 feeder and that at any age it may feed largely upon entomos- 

 tracans, insects, molluscs or almost anything else that is edible. 



In the present study of 138 specimens of the young perch 

 the results are generally in agreement with those of Forbes who 

 reported upon less than twenty fish of this age. Forbes con- 

 cluded that there are three periods to be recognized as expressed 

 in the food habits of the perch, infancy, in which the fish takes 

 only entomostraca and minute dipteran larvae, youth, in which 

 mainly larger insect larva are eaten and maturity in which 

 crayfish and fish constitute the food. In his younger specimens, 

 however, he finds the entomostracan food to be about equal 

 parts of copepods and cladocera while in the present study a 

 pure diet of copepods is encountered in the youngest fish. 

 Apparently the age classified as maturity by Forbes has just 

 been reached by the oldest specimens included in this report. 

 The statement of Pearse that perch are versatile feeders at all 

 ages is born out here except in the case of the youngest spec- 

 imens which have a pure diet of Entomostraca. 



Two reasons suggest themselves for the gradual but definite 

 change in the total diet of the young perch. (1) There is a 

 gradual increase in the size of the animals eaten which keeps pace 

 with the increase in size of the fish and it seems probable that 

 the perch would take larger animals as food unless it were 

 especially equipped for straining the water for smaller objects. 

 (2) The perch in its youngest stages is not a bottom feeder as it 

 is when adult. A gradual change results by its turning to the 

 bottom for food whereas it had formerly taken its food at the 

 surface or in the middle waters. The perch in its earlier stages 

 might be termed a generalized feeder becoming later a "ver- 

 satile feeder" (Pearse, 1918), but deriving most of its food along 



