NOTES ON THE FOOD HABITS OF YOUNG 

 OF COTTUS ICTALOPS (Millers Thumb.) 



C. L. TURNER 



Zoological Laboratory, Beloit College 



While the writer was engaged in collecting the fry of the 

 Perch and of the Darters in the vicinity of Put-in-Bay, pre- 

 paratory to making a study of their food habits a locality was 

 found in which the young of Cottus ictalops were fairly 

 abundant. 



Around the shores of Buckeye Island there is an abundance 

 of short, thick vegetation, shaded by willows and protected 

 and held together by willow roots. This margin is constantly 

 awash due to the exposed position of the island. The young of 

 Cottus ictalops and of the Fan Tailed Darter {Etheostoma 

 flabellare) were found hiding in the vegetation and under the 

 rocks in the vicinity. It was not possible to take the fish in a 

 seine because they were* so well protected but a small collection 

 was secured by persistently dragging the vegetation with a fiat 

 ended dip net. 



About a hundred specimens were taken ranging in size from 

 12 to 22 millimeters and the stomach contents of thirty-five 

 were examined. The food articles have been arranged in a 

 tabular form showing the proportion of each kind of food eaten 

 by each size of fish. 



Although ten different articles occur in the food some of 

 them are almost negligible in quantity and even the youngest 

 fish seem to prefer large, active Amphipods or insect larvee. In 

 some cases a single insect larva, two-thirds as long as the fish 

 filled the stomach. 



The young of most fish subsist on Entomostraca during the 

 younger stages, turning later to specialized and larger foods. 

 In a fish of generalized feeding habits the time during which it 

 takes Entomostraca is known as the period of infancy, a later 

 period when midge larvae and other minute insect larvae are 

 used is known as the period of youth, while the stage in which 

 the usual food of the adult is taken is designated as the period 

 of maturity. The period of infancy seems to be entirely omitted 



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