DEPARTMENT OF COMMERCE AND LABOR. 



BUREAU OF FISHERIES. 



Economic Circular No. 3 ::::::::::: Issued October 26, 1912 



MUSSELS OF CENTRAL AND NORTHERN MINNESOTA.' 



As a part of the series of mussel investigations conducted by the 

 United States Bureau of Fisheries, the lakes and rivers of central 

 and northern Minnesota were examined in 1912 to ascertain the 

 kinds and quantity of mussels they contained. As this was a prelimi- 

 nary survey or reconnoissance, no attempt was made to locate all of 

 the mussel beds or to determine their exact boundaries. The resuUs 

 which are of interest to mussel fishermen and pearl-button manu- 

 facturers may be summarized as follows : 



GENERAL CONDITIONS. 



Practically all this portion of Minnesota is covered with bowlders, 

 gravel, sand, and clay mixed indiscriminately, left by the melting of 

 a great glacier which formerly swept over the State, and the inequali- 

 ties of distribution of this glacial material have determined the loca- 

 tion of most of the lakes and river valleys. Furthermore, the grind- 

 ing action of the ice cut down the hills and filled in the valleys to a 

 great extent, leaving a comparatively level surface. As a result, all 

 the rivers and streams are very winding and have a rather slow cur- 

 rent. The lakes are full of sand and gravel bars, and the bottom of 

 both lakes and rivers is largely composed of sand and gravel, with 

 a comparatively small proportion of mud. These conditions exert a 

 marked influence on the mussels, and, taken in connection with the 

 fact that the water is full of lime and clear, except in the rivers that 

 drain from the Mesabi Iron Range, they make the entire region an 

 exceptionally good one for mussel development. 



For convenience the lakes and rivers are considered in six groups. 



LAKE SUPERIOR DRAINAGE. 



This contains no mussels of commercial value and practically none 

 at all. From the St. Louis Eiver, the largest in this drainage, 

 mussels and fish are effectually shut out by the dam and falls at 

 Carlton. And even if the fish had a clear passage, no mussels could 

 thrive in the river below Floodwood on account of the immense 

 number of logs driven down its waters every year. 



i-By Charles B. Wilson and Ernest Danglade, whose complete report will be published 

 by the Bureau later. 



