106 American Fisheries Society 



By depth of water is meant the distance from the 

 point at which the fish is taken to the surface, which 

 is usually, although not always, the distance from the 

 bottom to the surface. The localities may be indicated, 

 as in the table, by means of numbers which refer to a 

 map or by descriptive terms. It is convenient for pur- 

 poses of discussion to indicate each fish by a serial 

 number. 



A number of interesting facts at once appear from the 

 table. In July and August the pike in this lake are seen 

 to range from a depth of four feet to that of forty-five 

 feet. This depth-range at this season is explained by 

 the fact that below forty-five feet the water contains 

 little or no oxygen so that the pike cannot live there. 

 At other seasons they may range deeper. 



The food, so far as it may be learned from so few 

 records, consists entirely of fish. The four fish well 

 enough preserved for identification were perch. These 

 were taken in spite of the spines of their dorsal fins, a 

 hint perhaps to fishermen. 



Of the twenty pike whose sex was determined, half 

 were males. The males averaged about three ounces heav- 

 ier than the females, but the data are not enough to 

 warrant a general statement on this score. 



If we represent the length of each fish by a correspond- 

 ing distance measured along a vertical line and its 

 weight by distance along a horizontal line we may show 

 the length and weight of each by means of a point. Thus 

 in figure one, each inch of length is represented by a 

 space on the vertical line at the left; each ounce of 

 weight by a space on the horizontal line. The intersection 

 of horizontal and vertical lines drawn from the two 

 points thus located gives a point which shows at the 

 same time the length and weight of an individual fish. 

 Thus the point at the extreme right in our figure indi- 

 cates a fish of 30.6 inches length and 104 ounces weight. 

 The remaining points indicate the lengths and weights 

 of the pike in our table. Through these points we may 

 draw a curve as shown in the figure. This curve 



