Electrofishing and the effects of depletion sampling on fish health: A review and recommendations for additional study

Depletion sampling in combination with multiple-pass electrofishing is an important fisheries management tool for wadeable streams. This combination of techniques has been used routinely by federal and state fishery management agencies for several decades as a reliable means to obtain quantitative data on trout populations or to describe fish community structure. In this paper we review the effects of electrofishing on fish and discuss this within the context of depletion sampling and multiple exposures of fishes to electric fields. The multiple wave forms most commonly used in sampling (alternating current, direct current, and pulsed direct current) are discussed as well as electrofishing induced response, injury and physiological stress. Fish that survive electrofishing injuries are more likely to suffer short and long-term adverse effects to their behavior, health, growth, or reproduction. Of greatest concern are the native, non-target species that may be subjected to multiple electrical shocks during the course of a 3-pass depletion survey. These exposures and their effects on the non-target species warrant further study as do the overall effects of electrofishing on populations and community structure.