2 PLANKTON OF WINNEBAGO AND GREEN LAKES. 



that time. There is now hardly a better lake in the state for 

 fishing for sport for some kinds of fish. The perch are espe- 

 cially large and handsome, and the black bass are numerous and 

 gamy, although rarely exceeding three or four pounds in weight. 

 Pike, too, are caught in large numbers, and white bass are abun- 

 dant in the spring. 



Lake Winnebago is some 28 miles long by 10 or 12 broad in 

 its greatest width. There has never been an accurate hydro- 

 graphic survey of the lake, but it is probable that it is nowhere 

 over about 25 feet in depth. It is evident to a superficial ob- 

 server that the plant life during the summer is very large, and 

 it has been assumed that the abundant production of fish is 

 correlated with the plant growth. The principal inlet of the 

 lake, the Fox river, enters it about midway of the western shore, 

 and leaves it as its outlet, at the northern end. Thus the lake 

 may be considered simply as an expansion of the river. 



Connected with the Fox and its principal tributary the Wolf, 

 is a number of lakes and streams which receive the drainage of 

 a large section of the northeastern part of Wisconsin, extend- 

 ing from the southern boundaries of Marquette, Green Lake, 

 and Fond du Lac counties to the southern parts of Forest and 

 Oneida counties. 



Many of these lakes are merely expansions of the rivers, and 

 although covering areas of considerable size, are for the most 

 part, very shallow. Lake Buttes des Morts, Lake Winneconne, 

 Lake Poygan, and Lake Puckaway are the most prominent of 

 these lakes ; their shores are for the most part low and swampy, 

 and their depth rarely exceeds 10 or 15 feet. There are a few 

 deeper lakes in this drainage area : Stone lake is between 75 

 and 80 feet in its greatest depth; the Waupaca lakes, though 

 small in area, are in some cases from 60 to 95 feet in depth, 

 and Green lake, with a maximum depth of 237 feet, is the 

 deepest lake in the state. 



The deep lakes, as would be expected, are more distinctly cut 

 off from the other parts of the drainage area than the shallow 

 lakes. In the case of the shallow lakes, many open one into 

 the other so that there is no distinct line of separation between 



