Variation in the Community Structure of Fishes from Main Channel Border Habitat Among Reaches of the Mississippi and Illinois Rivers

We analyzed four years (2010 to 2013) of electrofishing data collected from the main channel border of the Mississippi and Illinois rivers by the Long-Term Illinois, Mississippi, Ohio and Wabash Rivers Fish Population Monitoring Program (LTEF) and long-term monitoring for the US Army Corps of Engineers Upper Mississippi River Restoration (UMRR).  Community structure of fishes differed significantly between the two rivers and among the reaches.  The Des Plaines Reach of the Illinois River and Pool 8 of the Mississippi River formed a distinct group, with less than 45% similarity to all other reaches within the two rivers.  Pool 8 and the Des Plaines Reach were characterized by high abundances of centrarchid sport fishes such as Bluegill and Largemouth bass.  Other important species separating groups include invasive species such as Common carp and Silver carp.  Our analysis revealed a surprising amount of overlap between the two rivers, including within finer-scale groups among river reaches.