20 MUSSELS OF CENTEAL AND NORTHERN MINNESOTA. 



At Prairie Lake, 6 miles north of Grand Rapids, the water is 

 considerably discolored with iron brought down by the Prairie 

 River from the Mesabi Iron Range. This iron does not appear to 

 affect the mussel fauna at all, since they are neither stunted nor 

 discolored. But thousands of logs are run down the Prairie River, 

 and the bottom of both the river and much of the lake is covered 

 so thickly with fragments of bark that no mussel can live in it. 



It is hardly necessary to add that all these lakes, the Mississippi 

 itself, and its tributaries are full of just the right kind of fish to 

 serve as hosts. Furthermore, Walker, Cass Lake, Bemidji, and 

 Grand Rapids are very conveniently situated for propagation work, 

 and are in easy railroad communication with all other parts of the 

 State. 



RECOMMENDATIONS. 



1. As noted under the Red River group, suitable passage should 

 be provided for fish around the dams at the outlet of Lakes Pokegama 

 and Winnibigoshish, and the large power dam 11 miles below Lake 

 Bemidji. These last two are across the Mississippi, and surely that 

 river ought never to be closed to the passage of fish, to say nothing 

 about the mussels. 



2. The farther the source of supply is removed from the button 

 factory the greater is the cost of transporting the shells. Therefore, 

 in a city like Bemidji, forming a convenient center, the establish- 

 ment of a local factory for sawing blanks can not be too strongly 

 recommended. 



3. This is not the best locality for trying the experiment of intro- 

 ducing commercial species of mussels into some of the Minnesota 

 lakes. But after such an experiment has been made a thorough suc- 

 cess, there are large and well adapted lakes here in which artificial 

 propagation would undoubtedly yield profitable returns. 



MUSSELS OF THE ISOLATED LAKES. 



LAKE PEPIN. 



This so-called lake is really a simple widening of the Mississippi 

 River just below Red Wing. The bottom is of fairly coarse gravel 

 mixed with some mud, there is very little current, and the water 

 varies from 6 or 8 to 12 or 15 feet in depth. This locality has not 

 been fished for mussels until within a few years, but at the time of our 

 visit there were 100 clamming outfits along the east shore of the lake, 

 and they were averaging more than 200 pounds apiece per day. 



An examination of the piles of shells collected by these fishermen 

 yielded examples of the following species: Lampsilis luteola, recta, 

 fallaciosa, and alata, TJnio gihhosus, Strophitus edentulus, Ohovaria 

 reflexa, and Quadrula plicata, undulata, and pustulosa. 



