Field evaluation of electrofishing response thresholds for adult Grass Carp

Abstract

Objective: Optimal electrofishing waveforms and parameters have been established for juvenile Grass Carp Ctenopharyngodon idella in controlled laboratory trials, but effective settings for adult Grass Carp in riverine systems remain to be determined. This work builds upon existing research by making opportunistic use of data collected in the Cuyahoga River, Ohio, to refine power standards for boat electrofishing that is used to target adult Grass Carp. Methods: Over 12 days of boat electrofishing surveys, we used a gradient of voltage settings at various ambient water conductivities to generate an electrofishing goal table for adult Grass Carp. Result: Our target power was 3550 W (1447–6507 W) higher, on average, than the target power recommended in previous studies for coolwater and warmwater fish species with 60 Hz. Results also show that a 40-A control box is inadequate in locations where ambient water conductivities exceed 576 μS/cm and when power is limited. Conclusion: Refining power standards for boat electrofishing that targets Grass Carp may increase catch rates to levels needed to suppress populations in the Great Lakes region and North America.