Creek chub can accurately reflect levels of contamination in rivers and streams.

In 1997 the Office of Water Quality of the Indiana Department of Environmental Management (IDEM) instituted a new monitoring policy.  Instead of just sampling water, they began sampling fish also. Sampling fish tissue enabled the “environmental scientists to measure the regional magnitude and extent of fish tissue contamination by specific bioaccumulating elements or compounds.” After two years they evaluated the effectiveness of the program. Specifically, they evaluated the suitability of creek chub as an indicator of mercury contamination.  To ensure reliability of the tissue samples, they were transported on dry ice, then placed in a laboratory freezer.  The report concluded the sampling program was effective, although it made some specific recommendations for sampling locations and other parameters.