Use of electrofishing for capturing invasive fish

Abstract

Electrofishing is the use of electricity to capture fish. The response of fish to pulsed direct current (DC) occurs in five phases, as shown in Figure 4.5. Electrotaxis occurs as a result of the electrical effect on fish muscles that contract with each electrical pulse, rather than its effect on the central nervous system. Each pulse of electrical current in a pulsed DC field causes the fish’s body to flex; it then relaxes between each of the pulses. This flexing and straightening action accentuates the involuntary swimming towards the anode (galvanotaxis). Pulsed DC causes tetany and narcosis at a much lower voltage gradient than continuous DC, so this is the preferred current delivery (Brousseau et al. 2005). Because invasive fish species inhabit a wide variety of non-wadeable habitats, this chapter will focus on boat electrofishing.