The American Midland Naturalist 
PUBLISHED BI-MONTHLY BY THE UNIVERSITY 
OF NOTRE DAME, NOTRE DAME, INDIANA 
VOL. VIIf. JANUARY, 1922. NO. tr. 
Final Report on the Study and Appraisal of Mussel Resources in 
Selected Areas of the Upper Mississippi River. * 
BY N. M. GRIER, PH. D. + 
Washington and Jefferson College. Washington, Pa. 
E INTRODUCTION. 
Sree the months of July and August, 1920, the U. S. 
Bureau of Fisheries made a study and appraisal of the mussel 
resources of the Mississippi River in and between the areas 
commencing at a point about five miles above Red Wing, Min- 
nesota, extending thence through Lake Pepin, and ending 
nearly 80 miles down stream at La Moille, Minn. More exact 
boundaries for the areas will be indicated hereafter. The 
work carried on was with reference to recent administrative 
action on the part of the states of Wisconsin and Minnesota, 
which provided for the closure of certain of these areas for 
the protection of the fresh water mussels, as well as for areas 
to remain subject to fishery. From the data acquired in this 
investigation, it is expected to establish a basis for compari- 
son of conditions in the present and after a period of pro- 
tection. 
II. GENERAL CONDITIONS IN THE AREAS. 
_ While usually attaining a depth of from 5-20 ft. within the 
limits of the state of Minnesota, the river at the time of this 
investigation was in a flood stage of from 2-9 ft. One ap- 
parent effect of the latter condition was to cause a migration 
of the mussels shoreward, as in general the outer limits of the 
shell beds are often determined by the deeper waters of the 
channel. The fall of the river is greater below L. Pepin than 
* Published with the authorization of the U. S. Commissioner of Fisheries. Contri- 
bution from the Fairport Biological Station. 
+ During this inestigation, Messrs. J. F. Mueller and W. Teachout served as 
assistants. 
