Effect of a Recently Completed Habitat Rehabilitation and Enhancement Project on Fish Abundances in La Grange Pool of the Illinois River Using Long Term Resource Monitoring Program Data

The Long Term Resource Monitoring Program (LTRMP) fish component monitors fish communities to test for changes in abundances and species composition in six regional trend areas of the Upper Mississippi River System. Using these data. we evaluated the ability of the LTRMP to detect changes in the fish community as a consequence of a habitat-enhancement project in La Grange Pool of the Illinois River. In 1996 initial phases of the Chautauqua National Wildlife Refuge Habitat Rehabilitation and Enhancement Project (HREP) south cell construction were completed with the goal of improving fish habitat in the pool. That year. an estimated 46 million fish representing 34 species were produced and discharged from the south cell of Lake Chautauqua. Whereas this response may indicate that the south cell serves as a spawning and nursery area for many fish species. no studies have tested for recruitment to the river fish community. We used geographic information system coverage at three spatial scales in the main-channel and side-channel strata to illustrate potential fish- community responses. At these spatial scales (local 1 river mile RM, regional approximately 10 RMs, and pool wide 80 RMs) we assessed fish catch-per-unit-effort (CPUE) data collected from mini-fyke net and day electrofishing among pre- (1993-1995) and post-HREP (1996-2005) periods of the Chautauqua National Wildlife Refuge HREP.