BIOLOGICAL SURVEY OF THE UPPER MISSISSIPPI RIVER, WITH 

 SPECIAL REFERENCE TO POLLUTION 



BY A. H. WIEBE 

 Temporary Assistant, United States Bureau of Fisheries 



CONTENTS 



Page 



Introduction 137 



Historical 137 



Aim and plan of the survey 138 



Acknowledgments 139 



Sampling stations 140 



Hydrometric data 142 



Dissolved oxygen 144 



Bottom fauna 145 



Relationship of bottom fauna and 



pollution 145 



Methods 145 



Results and discussion 146 



Page 

 152 



Plankton 



Relationship of plankton organisms 



and pollution 152 



Methods 152 



Results and discussion 154 



Fishes 160 



Summary of seining operations and 



results 160 



Discussion — fish and pollution 162 



Summary of results 165 



Bibliography 167 



INTRODUCTION 

 HISTORICAL 



The people of Minnesota and Wisconsin who are interested in the conservation 

 of the fish life of the Upper Mississippi River have claimed that the abundance of 

 fish in the river below Minneapolis and St. Paul is declining. Inasmuch as these 

 people know that all th e sewage and industrial waste from the Twin Cities (a com- 

 bined population of over 600,000) and from South St. Paul, where packing plants 

 are situated, are thrown into the Mississippi River without previous treatment, they 

 attribute the apparent decrease in the abundance of fish to the effects of this sewage 

 and trade waste. The conservationists of Wisconsin and Minnesota have demanded 

 that these cities be prohibited from dumping untreated sewage into the river. 



That this general belief in the decline in abundance of the fish in this region 

 is not unfounded may be seen from Table 1, in which the yields of the various species 

 of food fish in 1903 are compared with those in 1922. It is at once apparent that 

 although the total yield has more than doubled in the 19-year interval, this increase 

 is due almost entirely to the enormous catch of carp in the latter year, while the total 

 yield of all other food fish has declined materially. The most desirable or popular 

 species (such as black bass, crappie, pickerel, pike perches, sunfish, yellow perch, 

 and white bass) disappeared entirely from the commercial catch in 1922, the yield 

 of suckers was reduced greatly, and only those fishes that formerly were considered 

 of less value, such as the buffalo, bowfin, and drum (aside from carp), have increased 

 in yield. 



137 



