Midwest Fish & Wildlife Conference 2018

AUTHORS. Kristopher Maxson, University of Illinois; Levi Solomon, University of Illinois; Rob Maher, Illinois Department of Natural Resources; Andy Casper, University of Illinois

ABSTRACT. Long term monitoring of fishes and other biota can be incredibly valuable when assessing the health of a population, giving us the ability to observe trends over an extended period of time that can encompass various disturbances or extreme weather events.  One example of long term monitoring is the Upper Mississippi River Restoration (UMRR) Program’s Long Term Resource Monitoring element (LTRM).   Beginning in 1993, the LTRM element monitors fish and water quality in six reaches along the Upper Mississippi River System (UMRS). Study methods are standardized across the six reaches and employ a stratified random sampling (SRS) design. This standardized design allows comparisons among the six reaches and can help inform management decisions. For example, buffalo (Ictiobus sp.) are one of the most important commercially harvested species on the UMR. Despite this, little work has been done to assess buffalo populations. This study seeks to use Smallmouth Buffalo (Ictiobus bubalus) catch data collected from 1993-current to track trends in Smallmouth Buffalo populations.  Using catch data from hoop nets and day electrofishing, we calculated the catch per unit effort (CPUE) for Smallmouth Buffalo in each of the six LTRM reaches. CPUE data for the six LTRM reaches indicate a downward trend for Smallmouth Buffalo populations since the program’s inception. In contrast to the trends in LTRM data, Illinois commercial harvest levels of buffalo sp. have remained relatively stable since the 1950s. Future efforts will examine otoliths collected from Smallmouth Buffalo in 2017 to determine the age structure of the fish in each LTRM study reach. Data from this study can be used to help inform management of the Smallmouth Buffalo commercial fishery on the UMRS.