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.