226 American Fisheries Society. 



January, and these must have been swimming up early in February, 

 or about the time of the annual spring freshets of that region, where 

 many of the mountain streams rise to a height of 50 feet above 

 low water, producing torrents, and doing damage the like of which 

 would be impossible anywhere in Minnesota, with the possible ex- 

 ception of some of the North Shore streams. Yet these little fishes 

 withstood the tremendous forces of nature here exerted, and little, 

 if any, diminution of their numbers could be detected until the 

 waters became polluted by the advance of civilization, followed by 

 the devastation of large areas by forest fires, leaving the spring 

 sources deep in the earth to dry up and the waters gradually to sub- 

 side, often resulting in the complete obliteration of running streams. 

 The causes leading up to this change are an inevitable result of our 

 advance in agriculture and other pursuits connected with our ad- 

 vance in civilization, so that our responsibility to future genera- 

 tions leads us to look more deeply into the causes underlying our 

 failure to do so and so and to search for a remedy. IVe can assist 

 nature, but we cannot improve upon her methods. 



It was with a realization of the failures attending certain plants 

 of fish fry in apparently suitable waters that the desire to acquire 

 more or less accurate knowledge of our streams and lakes led to an 

 investigation of certain areas in the stat*'-. This was made possible 

 by acts of the legislatures of 1917 and 1919, m appropriating 

 nominal sums for that purpose. The summers of 1918 and 1919 

 were spent in an investigation along the eastern border of the State 

 in Pine County; the area covered approximately 650 square miles 

 of almost virgin forest country, where all the conditions of pris- 

 tine wilderness still prevail over large areas. The experience gained 

 in Pine County, and the pressing demand for information from 

 the older-settled regions of the State determined a more fixed 

 policy of procedure, and it was decided each drainage system should 

 be investigated in turn as completely as the circumstances per- 

 mitted. Therefore, the summer of 1920 was spent in a survey 

 of the Root River basin, a section of the State in which changes 

 first began with its settlement over 80 years ago. This basin covers 

 an area of 1,638 square miles in the southeastern corner of the 

 State, the main stream having a length approximating 151 miles, 

 with many tributaries, one at least being 65 miles long. 



We find the development of the agricultural possibilities of this 

 particular region necessitated the removal of a very heavy hard- 



