Perceived Influence and Response of River Users to Invasive Bighead and Silver Carp in the Illinois River

Two United States federally injurious fishes, bighead(Hypophthalmichthys nobilis)and silver carp(H. molitrix),are established in the Mississippi River Basinand have the potential tocolonize the Laurentian Great Lakes. Given this imminentthreat, a critical need for stakeholders is an understanding ofthe potential social influences of this invasion oncommunities that rely upon the ecosystems bighead and silvercarp now inhabit; influences so far unstudied. Using intercept surveys (n= 469), we tested forthe potential social influencesof bighead and silvercarp in four river communities;three in which they haveestablishedpopulations(test, Illinois River, Illinois) and one in which they have not(control, Mississippi River, Iowa). Reported principal differences between test and control sites were observed for recreational fishing, aestheticappreciation of the river, and experience with bighead and silvercarp. Our exploratory results indicate that bighead and silvercarp may have a negative influence on river usage.