Fresh-Water Mussels (Mollusca: Bivalvia: Unionidae) of the Upper Mississippi River: Observations at Selected Sites within the 9-Foot Channel Navigation Project on Behalf of the U.S. Army

摘要

A survey of freshwater mussels of the Upper Mississippi River drainage was conducted during the summer and autumn of 1977. Over 8,000 living specimens were gathered and examined during surveillance of more than 40 actual and/or potential dredging sites in the Minnesota and St. Croix Rivers and in almost 20 Upper Mississippi River pools. Dredging and associated activities to maintain the 9-foot navigation channel has caused local mortality of mussels, including endangered species. There are other factors having far greater adverse impact, including wastes from the cities of Minneapolis and St. Paul, agricultural runoff, impoundment of the Upper Mississippi River and encroachment by Corbicula fluminea, the Asiatic Clam. The outlook for a continuing ecosystematic and commercial mussel resource appear to be good. Even certain endangered species (e.g. Lampsilis higginsi) are likely to survive if appropriate measures are taken.