Effects of Electroshock, Air Exposure, and Forced Exercise on Swim Performance in Rainbow Trout (Oncorhynchus mykiss)

Swim performance of rainbow trout (Oncorhynchus mykiss) following forced exercise and pulsed DC electroshock both with and without subsequent air exposure was examined. Swim stamina was assessed by exercising fish at 39 cm/s until exhausted. Swim performance was impaired following all treatments. Increasing durations of air exposure (0–4 min) after electroshock resulted in progressively prolonged durations of swimming impairment (from 1 to 6 h). Electroshock reduced swimming stamina in a virtually identical fashion to that of 5 min of forced exercise. By comparison with the existing literature on the physiological effects of forced exercise, the impairment of swim performance most likely resulted from a reduction in intracellular pH.