Madison, Wisconsin: Wisconsin Department of Natural Resources
Summary
Unionid mussels were collected during the summers of 1977-79 in the main channel and associated backwater areas of the Upper Mississippi River from Prescott, Wisconsin to Dubuque, Iowa, a total of 229 river miles. Living mussels were collected on 2,663 five-minute tows with a 10-ft dovetail clam bar brail. SCUBA diving was also employed to collect living and dead mussels and to determine the efficiency of the brail. The average efficiency of brail runs was less than 1% when compared with SCUBA diving, which was considered 100% efficient.