Evaluation of an Approach to Integrated Pest Management of Bighead Carps and Silver Carps

Multiple investigations are developing methods to manage invasive Bighead Carp Hypophthalmichthys nobilis and Silver Carp H. molitrix that are spreading through the Mississippi River basin and threatening to invade others. This project integrated several methods to increase removal of Bighead Carp and Silver Carp from a backwater along the Illinois River near Morris, IL and to evaluate the efficacy of integrated pest management. Mobile hydroacoustic surveys were used to characterize the distribution of fish within the backwater then algal feeding attractants were injected at predetermined locations. A water gun barrier was established at the narrowest location of the backwater about 14 h before commercial fishing commenced.  The presence and distribution of fish near the water gun barrier was assessed by fixed and mobile split-beam hydroacoustic transducers. Mobile hydroacoustic surveys, algal feeding attractant injection and water gun barrier operation continued through 3 consecutive days of commercial fishing. Commercial fishers harvested fish via gillnets in predetermined zones on each day and recorded harvest by species, location and date. Presence of fish near the barrier and the change in fish distribution within the backwater as a function of algal feeding, water gun barrier operation and commercial fishing pressure was assessed.