Watergun Effective Distance over Time: A Spatio-Temporal Evaluation of Asian Carp Density before, during, and after Firing

Concerns of Asian carp spreading into new environments, particularly the Great Lakes, has prompted state and federal agencies to evaluate novel control options. In this study, mobile hydroacoustics were used to evaluate the effective of a stationary seismic watergun barrier on the spatial distribution of Asian carp in a canal between the Illinois River and a large backwater lake near Morris, IL where high abundances of adult Asian carp are present. Surveys were conducted at set time intervals before, during, and after replicated deployment of the watergun barrier over the duration of the two week study. In general, fish targets most likely to be Asian carp (>50 cm TL) were uniformly distributed throughout the canal during non-firing periods. During firing periods, large fish were not detected within 30 m of the watergun barrier and fish density declined within the entire 1,100 m channel. These results were generally consistent across repeated firing events, suggesting that Asian carp do not become acclimated to the pulse pressure emitted by waterguns and therefore may be an effective tool to mitigate the behavior of Asian carp. Additional information collected using continuous fixed-station hydroacoustics will help to determine the effectiveness of this barrier to fish movement.