Effects of Two Electrofishing Currents on Captive Ripe Razorback Suckers and Subsequent Egg-Hatching Success

Abstract In the laboratory, we assessed direct effects of electroshock by two types of square-wave pulsed DC in homogeneous fields of 1.0 peak volts per centimeter on ripe razorback suckers Xyrauchen texanus and evaluated subsequent egg-hatching success. Four males and four females were exposed for 10 s to a simple 60-Hz (24% duty cycle) current, and four males and three females were subjected for 10 s to a complex pulse pattern of three 240-Hz, 2.6-ms pulses delivered at 15 Hz (12% duty cycle). All shocked fish expelled some gametes during treatment. No external hemorrhages were observed, but X-ray and necropsy examinations revealed injuries associated with the spinal column in two males and two females subjected to the 60-Hz current and one female exposed to the complex pulse pattern; no injuries were observed in the four control fish (two males and two females). Mean percent egg hatch for fish shocked by either current was significantly lower (P ≤ 0.05) than that for control fish. Differences in hatchi...