180 Conservation Department 



VII. THE FOOD OF CERTAIN FISHES OF THE LAKE ERIE 

 DRAINAGE BASIN 



By C. K. Sibley 

 Instructor, John BuiTOughs School, Clayton, Mo. 



During the summer of 1928 food records were obtained for 64 

 species of fish. The alimentary tracts of 2,010 individuals were 

 examined and 1,128 of these contained food. 



In all cases, the length to the base of tail is used, that is, the 

 distance from the end of the snout to the end of the vertebral 

 column. The percentages given are estimates of the volume of the 

 various food organisms present in stomachs. The species examined 

 are grouped according to food preferences in order to facilitate 

 comparison. 



Species Feeding Mainly upon Animal Plankton. — While 

 plankton organisms are the sole food of many very young fish, 

 few species continue to take them in large quantities. A diet of 

 over 50 per cent animal plankton for fish more than two centi- 

 meters long was found in only four species, summarized as follows : 



Leucichthifs artedi. — Herring, cisco. Number of records, 53. 

 Length, 21.3-30.3 cm. or 8-12 inches. Daphnia pulex, 78 per 

 cent; Leptodora kindtii, 20 per cent; Limnocalanus macrurus, 2 

 per cent. 



Notropis atherinoides. — Emerald minnow, slender minnow. Num- 

 mer of records, 33. Length, 2.9-7.5 cm. or l%-3 inches. Daphnia 

 pulex, 46 per cent; Leptodora, 4 per cent; Bosmina longirostris, 

 1 per cent; Diaptomus sicilis and D. ashlandi, 4 per cent; Epis- 

 chura lacustris, 2 per cent; misc. adult insects, 36 per cent; misc., 

 5 per cent (silt, Oscillatoria, diatoms, Heptagenia, 1 earthworm). 



Lahidesthes siccnlus. — Brook silversides. Number of records, 

 15. Length, 1.9-3.5 cm. or ^/i-l^i inches. About 50 per cent of 

 the food was Cladocera; Acroperus harpae; Alona rectangnla ; 

 Chydorus sphaericus ; Scapholehris mucronata. Second in import- 

 ance was the copepod Leptocyclops agilis and third was insects 

 found either near the surface or floating on the surface, midge 

 pupae and adults; Corixidae ; Collembola ; 1 thrips and 1 aphid. 



Perca flavesccns. — Yellow ])ercli ; a plankton diet was found in 

 limited groups of this species.* 



Assistance in the identification of material was given bv Messrs J. R. Greeley, 

 P. R. Burkholder, W. L. Tressler and Dr. C. B. Wilson. 

 * See table 2, p. 185. 



