AN ASSESSMENT OF THE ANDERSON LAKE FISH COMMUNITY.

Michael A. McClelland, Kevin S. Irons, T. Matt O'Hara, and Mark A. Pegg.  
Long Term Resource Monitoring Program, Illinois River Biological Field Station, Havana, IL
62644.

Anderson Lake is a backwater lake in the La Grange Reach of the Illinois River downstream of
Havana, IL.  In 1999, staff at the Illinois River Biological Field Station began sampling Anderson
Lake during the months of June-September as part of the Long Term Resource Monitoring
Program (LTRMP) sampling of the La Grange Reach.  Approximately 24 sites were sampled
randomly each year including one offshore fixed site.  Multiple gears were used to sample the
lake, including fyke nets, mini fyke nets, tandem fyke nets, tandem mini fyke nets, and day
electrofishing.  The offshore fixed site was sampled only through electrofishing.  Approximately
33 species of fish were collected each year with a total catch of over 5,900 fish.  Comparison of
day electrofishing runs for 1999 and 2000 between Anderson Lake and all of the La Grange
backwaters combined shows that Anderson Lake species richness and catch per unit effort
(CPUE) is below the average for backwaters in the La Grange Reach.  Specific comparisons of
day electrofishing runs were made with a backwater lake (Matanzas Lake) that received a similar
amount of effort. Species richness and CPUE of day electrofishing runs in Matanzas Lake was
much higher for both years.  Possible explanations for the lower species richness and abundance
could be due to water quality, sedimentation, and level of connectivety to the Illinois River. 
Lower fish abundances and how they relate to abiotic factors will be discussed. 

Keywords:  Illinois River, Long Term Resource Monitoring Program, backwaters, La Grange
Reach, Anderson Lake