Upper Midwest Environmental Sciences Center
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Figure 17. | Mean fingernail clam (Sphaeriidae) abundance in the Upper Mississippi River System from 1993 to 2004. The Open River Reach was dropped from the macroinvertebrate monitoring design in 2001. Pools 4 and 26 of the Upper Mississippi River and La Grange Pool of the Illinois River were not sampled in 2003. |
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Page Last Modified: April 17, 2018