Evaluation of Acute Temperature Change and Thermal Acclimation on Response of Bighead Carp to Electrical Exposure

Temperate fishes, such as the extremely invasive bighead carp, have adapted mechanisms to tolerate a wide range of water temperature. Water temperature at locations, such as the Chicago Sanitary and Ship Canal, where Electric Barrier Systems are used to deter dispersal of nuisance fishes, varies markedly, seasonally. We examined the effect of temperature on various responses of juvenile bighead carp to a pulsed DC electrical exposure. Metrics of swimming performance (distance moved, mean and maximum velocity) and time spent in various states of mobility differed significantly (P < 0.05) among fish acclimated to 20⁰ C and receiving electrical stimulation during acute exposure to 10, 15, 20, 25, or 30⁰ C. Threshold field strength for behavioral endpoints such as first response, hyperactivity, loss-of-posture, and immobility and metrics of swimming performance and mobility states differed significantly between fish thermally acclimated to 10 and 27⁰ C (P < 0.05). Physiological modifications allow high performance by fish across temperatures. Nonetheless fish passed more quickly to graded states of electroshock-induced immobilization in water of low temperature and less quickly in water of higher temperature. Water temperature may significantly influence performance and reliability of electric field-based fish guidance and deterrence systems.