2i6 CoUciic of Forcslry 



Brook Silvcrsidcs {Lahidcslhcs sicciilus). Adult 51 nun. (p. 181). 



Adult midges 17 



Water miles 2 



lUisiiiiiia liiii(/irostris 74 



• Total uumliLr ol" s])rciinciis Q3 



L'pwafds of I 10 lish wcfe examined for food; in J() llie 

 digesli\e tiacls were empty and in (^4 there was more or less 

 food ill the stomach or digesti\e tract. In percentages this 

 means 30.9 empty and 69.1 with food. Of the 110 individuals 

 examined hut 13 or 11.8 percent had the stomach and digestive 

 tract full enough to give satisfactory data, and the information 

 furnished by the Oneida Lake lish is therefore meagre and 

 unsatisfactory on this particular point. It is all there is at 

 hand, however. The value and urgency of an accurate and 

 exhaustive study of the food habits of our fish is apparent. 

 The 13 fish listed on the previous pages show a total consump- 

 tion of 106 mollusks and 1,258 associated animals, or an 

 average of 8.1 mollusks and 96.7 associated animals per fish. 

 There was a small amount of macerated matter besides broken 

 shells, caddis-fly cases, etc., in some of the fish, averaging per- 

 haps 10 percent of the amount present, which should be added 

 to the larger amount, raising the average ciuanlil}- ])er fish to 

 8.C) mollusks, and 10O.4 associated animals, a total of ii5-4 

 animals per fish. 



The young fish and those adult fish that feed almost exclu- 

 sively on ])lankton organisms are not here included, no detailed 

 work having been done on the plankton of the lake. Reighard 

 (15, p. 224) examined the digestive tract of a youn^'^^ Common 

 Sucker (Catostomiis commersonii) upwards of two inches 

 long, and estimated that there were 2,400 Chydorus and 48 

 copepods present, indicating that young fish are large con- 

 sumers of the plankton. Juday ('07, p. 142) examined the 

 stomach of an adult Tahoe Ti"out (SaJnio liciishazvi Gill and 

 Jordan) 15 inches long and estimated that it contained 1,739 

 specimens of Daphnia (about two-thirds Daphma pidcx and 

 the rest Daphnia hyal'ma) showing that some adult fish are 

 also large consumers of plankton animals. 



