Abstract: We investigated the repellency and safety of electric barrier with different electrode arrangements and electrical parameters on silver carp (average body length of 21.05 cm). Under static water condition, an orthogonal experimental design with four factors and three levels was adopted to study the impacts of electrode arrangement, pulse voltage, pulse frequency, and pulse width on the blocking effect of electric barrier and the number of injured experimental fish. Under the conditions of inlet velocity of 0.3 and 0.5 m·s^-1, the optimal electrode arrangement and electrical parameters were used to repeat the experiment to explore the adaptability of the electric barrier at different velocities. Under the static water condition, the blocking effect of the second condition (electrode arrangement 1 with pulse voltage of 80 V, pulse frequency of 10 Hz and pulse width of 30 ms) was the best, with a blocking rate of 100%. The order of influencing factors with respect to strength was pulse voltage, pulse width, electrode arrangement, and pulse frequency. There was no significant difference in the average blocking rate of the same factor at different levels under static water condition. Further, the optimal electrode arrangement and electrical parameters, which were obtained under static water condition, were adopted. When the inlet velocity was 0.3 m·s^-1, the average blocking rate of electric barrier was the same as that under static water condition. When the inlet velocity was 0.5 m·s^-1, the average blocking rate of the electric barrier decreased to 97.92%, which had no difference with that under static water condition. Electrode arrangement and inlet velocity could significantly affect the average number of injured experimental fish, and the variation of the average number of attempts with inlet velocity was highly similar to that of the average number of injured experimental fish. Our results provide reference for the design optimization and engineering application of electric barrier, further improving its safety and effectiveness.

Key words: electric fish driving, pulsed direct current, electrode arrangement, electrical parameter, silver carp.