Effect of Electric Field Strength and Current Duration on Stunning and Injuries in Market-Sized Atlantic Salmon Held in Seawater

Abstract We evaluated electricity as a stunning method before slaughter of Atlantic salmon Salmo salar by assessing both stunning effectiveness and injuries. About 300 salmon (1.2–6.6 kg) were exposed to one-phase, sinusoidal, 50-Hz AC in seawater; electrical field strengths ranged from 15 to 250 V/m and current durations from 0.2 to 12 s. We measured the duration of the epileptic-like seizures after stunning and the degree of unconsciousness based on behavioral responses. Fish were killed, bled, and gutted 10 min after stunning and then analyzed for injuries. The proportion of fish sufficiently stunned, the duration of an unconscious condition, and the occurrence of broken vertebrae and hemorrhages were all dependent on electric field strength and current duration. The electric field strength required to stun the fish was inversely proportional to the current duration, dropping from 200 V/m at 0.8 s to 25 V/m at 6–12 s. Electricity proved to be efficient in stunning fish, but to avoid injuries in market-...

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