Mississippi National River and Recreation Area - Upper Mississippi River Mussel Counts (U.S. National Park Service)

The National Park Service and the Minnesota Department of Natural Resources (DNR) surveyed the 72 miles of Missisippi River and 4 miles of Minnesota River that constitute the Mississippi National River and Recreation Area. The Minnesota DNR began this important work with the Statewide Mussel Survey, during the 1999 field season. The statewide survey continued during the 2000 field season and in the 2001 season with the involvement of the National Park Service's Inventory and Monitoring Program.

During the 2000 field season, the DNR was able to sample a total of 60 sites along the metropolitan Mississippi River corridor. In 2001, 108 sites were sampled. A total of 13,589 live mussels were collected over the two survey years. Some species were found in one year and not in the other. Forty-two of Minnesota's 49 species were found in this stretch of river; 22 of those were live.

Mussels

Figure 1.1

Species present at less than 1% of total
Species	2000 Survey	2001 Survey
Pink Papershell	57	68
Fawnsfoot	33	20
Rockshell	15	16
White Heelsplitter	8	17
Paper Pondshell	3	3
Creek Heelsplitter	3
Hickorynut	2	10
Round Pigtoe	2	6
Elktoe	1	3
Spike	0	14
Mucket	0	6
Butterfly	0	2
Wasboard		2
Monkeyface	0	1

The table shown above lists the number of mussels found for those species that made up less than 1% of the total. A zero (0) means that no live mussels of that species were found. If the number field is blank, it means that no live or dead mussels of that species were found in that survey year.

Figure 1.2

Fluted Shell	Higgin's Eye
Purple Wartyback	Sheepnose
Yellow Sandshell	Cylindrical Papershell
Lilliput	Pistolgrip
Spectaclecase	Winged Mapleleaf
Ebonyshell	Elephant Ear

None of the mussels listed in this table were found alive, but the presence of their shells indicates they were once present in the corridor.

The graph "Mussel Survey Data" shows species that were present in numbers greater than 1% of the total.

The results of these studies are very encouraging. The U.S. Army Corps of Engineers and the National Academy of Scienc sampled the Upper Mississippi in the late 1970s. Their findings painted a dismal picture for the health of the river. Where today, we find 28 live species in this stretch of river, in the 70s there were only nine. Where now mussels can be found througout the river corridor, 30 years ago, their range was restricted to just below Lock and Dam 1. With improved wastewater treatment techniques, separation of sewer and storm drains, and restoration of habitat, mussels are making a comeback.