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AUTHORS: Daniel Roth, Eastern Illinois University; Jordan Pesik, Eastern Illinois University; David Wahl, Illinois Natural History Survey; Robert E. Colombo, Eastern Illinois University.
ABSTRACT: Invasive bigheaded carps of the genus Hypophthalmichthys pose significant ecological risks to ecosystems throughout much of the Midwestern United States. These two species, bighead and silver carp, spread extensively throughout many large rivers including the Illinois and Wabash River basins. Monitoring reproduction and early life stages of these fishes is critical in identifying factors that promote their spread into novel ecosystems. The goals of our study were to monitor abundance of early life stages of Hypophthalmichthys carps in tributaries of the Illinois and Wabash Rivers, and to compare the efficiency of three sampling gears. From March through October of 2016 we sampled larval fish in six tributaries using both active and passive ichthyoplankton nets, as well as quatrefoil light traps. Preliminary results suggest limited spawning of Hypophthalmichthys carps within these tributaries, only occurring late in the season near confluence areas. Comparison of sampling gears showed highest catch per unit effort (CPUE) for quatrefoil light traps, followed by active ichthyoplankton nets, and lowest for passive nets. Light traps caught the widest range of life stages, from gas bladder emergent stages to adult Cyprinids. Further analysis is necessary to directly compare efficiencies of the two net types, but we expect to see a wider range of life stages and sizes present in active net samples compared to passive net samples. Although invasive carp reproduction within our study rivers was limited, continued monitoring is necessary to determine if tributary spawning varies annually or across a wider range of hydrological conditions. Results of this ongoing study have the potential to identify what habitat types and environmental factors promote the abundance of these invasive fishes. This is of upmost importance in these systems because they represent potential corridors for dispersal, and contain significant ecological and economic resources.
Wednesday February 8, 2017 9:40am - 10:00am CST
Grand Ballroom F