Biological Survey — Oswego Watershed 193 



Streams near Ithaca were chosen for study because first of all, 

 indoor laboratory facilities were essential and easily obtained 

 here, and secondly, the trout streams in this vicinity are typical 

 of thickly populated regions, are heavily fished, and flow, for the 

 most part, through cultivated lands. 



Places in streams where studies were made are designated by 

 the term "station" and given numbers (see appendix, maps 1 

 and 6). Stations were not numbered in sequence or any particular 

 order and were given numbers after a given set of studies had 

 been completed. Stations number 1, 2, 3, 4, 6, 8, 9, 12 and 17 were 

 located on Sixmile creek; numbers 7 and 15 at the headwaters of 

 Newfield creek; 5 on a tributary of Virgil creek about three- 

 fourths of a mile east of Dryden, N. Y. ; 10, on lower Enfield creek 

 and 18, on the East Branch of Fish creek (Lewis county) about 1 

 mile west of Michigan Mills. 



Relation of Width of Stream to Quantity of Food Or= 

 ganisms. — Leger* states that the food of a stream decreases by 

 one half from the shore line to the middle of the channel in a 

 stream five meters or more in width (16.4 ft.) and that the nutri- 

 tive elements are found mostly along the banks at a distance of 1-2 

 meters from the shore. He also notes that small headwater streams, 

 narrow in width, are usually very rich in food. 



In order to gather data on this problem all the animals were 

 collected from three separate square feet of bottom taken trans- 

 versely across each stream over three feet in width, arranged as 

 follows : the first square foot unit area was taken in shallow water, 

 near one shore and in relatively slow current ; the second in mid- 

 stream in the center of the channel in the deepest water and the 

 swiftest current, and the third was in shallow water, moderate cur- 

 rent near the opposite margin and in approximately the same 

 corresponding position as the first square foot. 



The apparatus used in making these unit area catches consisted 

 of a galvanized iron box, one foot square inside measurements, 

 18" deep with square sieve dipper for washing and dipping out 

 organisms (Fig. 1). This apparatus was found very satisfactory 

 for obtaining practically all the available fish food from one square 

 foot of bottom in all situations studied. 



After collection the specimens were brought to the laboratory, 

 sorted and weighed. The total catch of available food from one 

 square foot was weighed together, separate- individuals or cate- 

 gories of organisms not being weighed unless an extra large indi- 

 vidual or group was taken, which would throw the weight off in 

 proportion to numbers. 



Table 1 shows the results obtained. The weight in grams obtained 

 by weighing the animals taken from the separate square feet of 

 bottom are given by station number and in sequence by stream 

 width. The column "Av. difference wt. in grams" gives bv 



Loc. cit. p. 27. 



7 



