Behavioral responses of native and invasive fishes of the Upper Mississippi River to 100 hp boat motor acoustic stimulus

Acoustic deterrents are currently being considered for deployment at strategic bottlenecks, such as lock and dams of major rivers, to deter upstream movement of invasive carp. Previous studies have demonstrated that bighead and silver carp ( Hypophthalmichthys nobilis and H. molitrix , respectively) display negative phonotaxis to playbacks of broadband sound recordings produced from a 100 hp outboard boat motor. However, there is concern that acoustic deterrents may impact the movement of non-target native fishes in the Upper Mississippi River. We evaluated the potential impacts of a broadband underwater acoustic deterrent on native ostariophysans [bigmouth buffalo ( Ictiobus cyprinellus ), channel catfish ( Ictalurus punctatus ) and fathead minnow ( Pimephales promelas )], invasive ostariophysans [bighead carp, common carp ( Cyprinus carpio ), grass carp ( Ctenopharyngodon idella ) and silver carp], and native non-ostariophysans [(American eel ( Anguilla rostrata ), gizzard shad ( Dorosoma cepedianum ), hybrid striped bass ( M. saxatilis × M. chrysops ), lake sturgeon ( Acipenser fulvescens ) and paddlefish ( Polyodon spathula )]. Fish were exposed to playback of the broadband sound (60–10000 Hz), and their behavior was evaluated. Bighead carp showed a strong negative phonotaxis response to the stimulus [12.3 ± 7.5 (SD) mean consecutive reactions], silver carp and grass carp showed moderate responses (4.5 ± 5.2 and 3.8 ± 3.5 reactions), and common carp displayed low responses (1.3 ± 1.9 reactions). Of the native fish, bigmouth buffalo (2.1 ± 2.9 reactions) and hybrid striped bass (0.3 ± 0.5 reactions) were the only species to demonstrate observable response to the acoustic stimulus. Based on this small-scale behavioral screening, acoustic deterrents should have minimal impact on native species; however, larger pond and field trials are necessary to confirm this finding.