We examined the use of “edge of flood” habitats by larval silver carp during the extensive flooding that occurred in Pool 26 of the Upper Mississippi River near Alton, IL, USA and St. Louis, MO, USA during the summer of 2015. We captured over 12,700 individual fishes including eight taxa, over 12,000 of which (> 95%) were larval silver carp between 5 and 21 mm standard length. Peak catch rates occurred near the confluence of the Illinois and Mississippi rivers. These findings suggest that larval silver carp have an affinity for edge of the flood habitat and further study is needed to better understand how this affects the dynamics of this invasive species in the Mississippi River. The high catch rates observed at the confluence of the Illinois and Mississippi rivers suggests that the Illinois River is an important source of larval silver carp to the Upper Mississippi River.

Using archaeological and ecological data of animal communities, and fish communities in particular, we test for evidence consistent with the Anthropocene in the lower Illinois River valley across millennia. Environmental impacts by preindustrialized peoples may be minor compared to current alterations; however, this hypothesis is untested and should be assessed. Using the relative abundance of fish taxa, we tested for differences among archaeological and modern time periods, taking advantage of published zooarchaeological data sets and newly analyzed data. Collections from all archaeological time periods differed significantly from modern collections, but the relative abundance of fishes did not differ significantly among archaeological time periods. Sociopolitical context, material culture, plant-based subsistence patterns, and the use of animal classes shifted temporally, but these differences did not extend to the relative abundance of fish families. Our results suggest that dominating human influences on fish communities did not occur prior to the Late Woodland period in the lower Illinois River.