Introduction to Sound and Guided Response of Bigheaded Carp to Acoustic Deterrents

Acoustic deterrents are a behavioral guidance technology with potential to control movement of fish.  In order for sound to guide movement, fish need to use information from the sound field to either orient to or localize its source.  Currently, it is unclear what orientation mechanism guide fish movement during avoidance responses.  Acoustic deterrents may be a useful management tool to control the movement of invasive fish with specialized hearing abilities like silver carp (Hypopthalmichthys molitrix) and bighead carp (H. nobilis) (collectively bigheaded carp).  We characterized the phonotaxic (movement oriented with respect to the sound field) used by bigheaded carp to avoid a sound source through laboratory trials using underwater speakers playing outboard boat motor sounds.  Avoidance behaviors of were characterized by >70% reduction in time spent near the speaker when sound was played.  Comparisons between fish movement and the local sound field components demonstrated carp are strongly repelled in a highly directional manner aligned with the axes of local particle motion.  In this talk I will discuss past and ongoing results as well as the potential role of acoustic deterrents in management efforts to control movement of invasive carp.  (Funded by Minnesota Environmental and Natural Resources Trust Fund).