222 Lake Maxinkuckee, Physical and Biological S^irvey 



-^ the lake and carrying of oxygen to the deepest parts. In 

 this manner the entire lake will become fully supplied with oxygen 

 early in the winter and so remain until the next fall when the 

 accumulation on the lake bottom of dead animals and plants which 

 have been showering from the upper layers all spring and summer 

 again exhausts the supply and the lower strata again become de- 

 void of oxygen. 



This matter has been quite thoroughly worked out on several 

 lakes by Messrs. Birge and Juday of the University of Wisconsin, 

 and the importance of the knowledge thus obtained can scarcely be 

 overestimated. 



The important fact disclosed is that the waters of some lakes 

 at certain periods in the year are practically without oxygen below 

 certain depths. ' 



As fishes are dependent for the oxygen they require upon the 

 absorbed oxygen contained in the water it is evident that water 

 containing no absorbed oxygen cannot support fish life. In order 

 that a lake may be suitable for the deeper freshwater fishes it is 

 necessary that the v/ater in the depths shall contain an adequate 

 supply of absorbed oxygen at all times. A lake may have an 

 abundant supply of oxygen at all depths for ten or eleven months 

 of the year, but if the supply is inadequate for one month or even 

 a briefer period, the deepwater fishes will perish unless, perchance, 

 Ihey are of species that can adapt themselves to shallower depths. 

 But few, if any, of our important freshwater fishes possess that 

 ability. Keeping that fact in mind it is now easily understood why 

 certain lakes, otherwise suitable, do not contain any deepvv^ater 

 species such as lake trout, whitefish or lake herring. 



During the past 30 years the Federal Government and various 

 States have spent thousands of dollars in making plants of white- 

 fish, lake herring and lake trout in lakes many of which we now 

 know to be deficient in oxygen during at least a portion of the 

 year. Lake Maxinkuckee is included in this list, four large con- 

 signments of lake trout having been placed in it in 1890 to 1894. 

 We now understand why nothing was ever seen of the fish after 

 they were liberated in the lake. 



In the past millions upon millions of fish have been planted in 

 the lakes and streams of the United States and usually without any 

 scientific investigation whatever for the purpose of determining 

 whether the waters were suitable for the fish which it was proposed 

 to plant in them. The result is that hundreds of thousands of dol- 

 lars have been spent and millions of fish wasted without any results 

 of value being obtained. 



