Behavioural response of downstream migrating European eel (Anguilla anguilla) to electric fields under static and flowing water conditions

Like many other species of diadromous fish, the European eel (Anguilla anguilla) is threatened by entrainment at hydropower intakes and resultant injury mortality during passage through turbines. Historically, physical screens have been installed to prevent access but these are not wholly effective can incur high costs construction maintenance, especially when regulations require screen retrofits with increasingly fine mesh. There interest in use potentially less expensive behavioural guidance methods block or guide movements. Electric barriers developed several information relating their effectiveness for limited. In this study, two experiments were conducted quantify response downstream migrating adult (silver-phase) electric fields electricity First, a static water tank was used identify field strengths (Vcm−1) required induce threshold responses three key behaviours (twitch, loss orientation tetany) across different pulsed direct current (PDC) waveforms (single pulse-2 Hz, double Hz single pulse-10 Hz) (Experiment 1). Second, recirculatory flume investigate how avoidance (acceleration, change rejection) differed between velocity regimes [0.5 ms−1 1.0 ms−1] [≈ 0.15 Vcm−1 ≈ 0.3 Vcm−1] identified first experiment 2). Experiment 1, lower needed elicit tetany under compared waveform, there no effect waveform behaviours. 2, frequent (31.4%) low (74.5%) velocity, strength did influence exhibited. This study provides insights into potential deter eel. The likely limited higher velocities.