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80 Sec ^.^.^-^-^-^^^ B R ~~~ ECG ~« ~ J. FISH. RES. BOARD CAN., VOL. 33(1), 1976 BR Mwe ECG ~uil;uuuw,uul+ u? Frc. 3. Polygraph tracing of buccal pressures (breathing rate, BR) and heart rate (ECG) of two trout - the upper shocked for 4S s and the lower shocked for 15 s. Tracings to the far left represent baseline values and were taken immediately before shocking. Tracings to the right were begun as soon as the shocking was discontinued (c = cough, t = T wave). packed cell volumes and plasma protein, calcium, magnesium, and androgen levels (Table 1) . Only variances in male sex hormones were hetero- geneous. The percentage of thrombocytes in reIa- tion to leukocytes was significantly different be- tween shocked and unshocked fish (Table 2). There appeared to be an immediate doubling of thrombocytes in shocked fish. This ratio of throm- bocytes in the blood returned to normal levels within L h, however, and remained at these levels 3 h post shock. Percentage thromocytes decreased significantly in the blood 6 h after shocking, as compared to the percentage in the blood of the controls, but showed no statistically significant decrease when compared to levels obtained at 1 and 3 h. Mean percentage of thrombocytes did not differ between control fish sampled at time 0 (1.7°Io) and 6 h later (0.8%). RESPIRATORY AND CARL nC ACTIVITY Two patterns were toted during recovery im- mediately after shocking (Fig. 3). Either the fish did not resume breathing for 60 s or they coughed violently during the first 30 s after the current had been discontinued. Potentials evoked by coughing were evident on the ECG tracings. The ECG patterns were irregular for several seconds after the shock. All shocked fish exhibited a marked. increase in amplitude of the T wave, which peaked in 1-3 min and declined to normal within 4-5 min after the shock was discontinued. During this period the magnitude of the T wave was equal to that of the QRS complex in several fish. Thereafter, no effects of electroshock were evident in heart or breathing rates. Synchrony between breathing and heart rates was not evident, and coughing patterns other than those mentioned were not affected. In fish that survived the shocking, breathing amplitude increased substantially (SO-3S0°I° ) (Fig. 4), beginning in some individuals during the first postshock interval. Buccal pressure am- plitudes continued to increase for 10 min. There- after, amplitude decreased to maintenance levels within 60-90 min. One fish shocked for 4S s and one fish shocked for 60 s died. Neither of these fish resumed breathing after the shock. Occasional spasmodic contractions affecting buccal pressures were evi- dent. Cardiac activity patterns appeared to be recovering normally initially but, thereafter, de- creased in both frequency and amplitude until they ceased altogether in 15-25 min. ISOENZYME PATTERNS None of the isoenzyme systems examined ap- peared to be influenced by the electroshocking. "There was no difference in banding patterns be- tween shocked fish and those captured in dipnets in liver LDH, TO, EST, and 1DH, white muscle GPI, AGM, AGP, AAT, GP, MDH, and ME, and plasma GP and LDH.