220 Conservation Department 



XI. QUANTITATIVE STUDIES OF THE FISH FOOD i 

 SUPPLY IN SELECTED AREAS \ 



By p. R. Xeedham 1 



Instructor in Limnology and Ecology, Cornell Universitij ', 



During the summer of 1927 work was started upon a few of the | 

 main problems relating to trout foods as they are found in the 

 streams in New York State. This work was continued during the | 

 past summer (1928) as the problems seemed to warrant further in- j 

 vestigation, the data obtained in 1927 being insufficient upon which | 

 to base definite conclusions. Also this summer several additional 

 projects were started, the results of which are presented here. ! 



The problems under consideration in this report are as follows : 



(1) Relation of width of stream to quantity of food organisms 

 (continued from last year). , 



(2) Relation of bottom types to quantities of food (continued j 

 from last year). j 



(3) Amounts of terrestrial insects Avhich fall into the water j 

 (defined as ''stream drift", 1927) and the consiunption of this 

 class of food by trout. 



(4) Productivity of various types of aquatic plants in relation | 

 to trout foods (continued from last year). 



Last season's work was entirely on available foods, those actually 

 eaten by trout not having been considered. This summer, in 

 connection with problems 3, stated above, trout were taken for 

 stomach examinations in order to correlate available foods with j 

 foods consumed. The principal streams in which these studies ' 

 were carried on were Sixmile creek, Newfield creek, Ilaybrook, and | 

 Owasco inlet near Ithaca, N. Y., and Heron brook, Point Rock 

 creek, and Fish creek near Constableville, N. Y. 



Relation of Width of Stream to Quantity of Food Organisms. 



— The apparatus anrl methods used in getting data upon this i 

 problem have already been described^ and need no further com- 

 ment here. In Table 1 will be found the combined results of two 

 seasons' work upon this problem. 



Leger^ has stated that, in a stream over 5 meters in width ! 

 (16.4 ft.), the food decreases one-half or 50 per cent from the | 



Mr, E. H. Wheeler of Hobart College, Geneva, N. Y. and Mr. William Phillips of 

 Ithaca assisted the writer in this work. 



^ See Biological Survey of the Oswego River System, supplemental to Seventeenth 

 Annual Report. N. Y. State Conservation Department. 1927. 



' Leger, L. Principes de la Methods Rationelle du Peuplement des Cours d'eau 

 a Salmonides. Travaux du Laboratoire de Pisciculture de L'Universit6 de Grenoble. 

 Fascicle 1, p. 531, 1910. 



