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CURRY AND KYNARD: BEHAVIORAL EFFECTS OF EXTENDED GALVANONARCOSIS 1301 TABLE 4. Individual test results of group activity for ruinbow trout immediately after 3 h of galvanonarcosis. H = hetero- geneity chi-square; P = probability of larger value of chi- square; os = nonsignificant chi-square value. Test Control Expected x2 df P 43 46 44.5 0.101 1 .90 ns 32 70 51.0 14.157 1 .005 32 40 36.0 0.889 1 .50 ns 39 41 40.0 1.050 1 .90 ns 47 48 47.5 0.011 1 .95 ns - - - - - 193 245 219.0 Total 15.208 5 .005 Pooled 6. 174 1 .005 H 8.034 4 .10 ns questionable. During immediate evaluations, treated trout displayed bursts of upright swimming and opened their gills as if coughing. Swimming action of control fish was more continuous and without opercular flaring. The measured group activity index of treated fish did not change significantly after 24 h, yet their observed activity was not equivalent to that of control groups. It appeared that trout treated for 3 h still suffered side effects even after recovery for 24 h. . An additional measure of group activity would have been helpful in the analysis. Control fish were observed to cluster more during the immediate evaluations than treated fish. Test fish would not start responding as a group until the end of the evaluation period. This clustering behavior was evident in both experimental and control groups after 24 h. Quantifying this be- havior may be a better way to evaluate the effect of electrical treatment in this case. It appeared that extended galvanonarcosis affected the muscles more than the sensory system. Activity evaluations showed that the motor activities were defi- nitely deprcssed in fish immediately after treatment. Treated fish were able to detect habitat differences as indicated by the study of photonegative response. In the predation tests, treated fish did not react to predator approach or disperse to the surface as quickly as con- trol fish. The depression of motor activity in electrically narcotized fish may be due to an extreme lactate in- crease and an oxygen debt incurred while under gal- vanonarcosis. Schreck et at. (1976) found that lactate increased rapidly in rainbow trout that had been electro- shocked. They observed that trout responded to electro- shock as if they were suffering from extreme muscular exertion andlor hypoxia. It is not known whcther fish experience these same physiological changes under galvanonarcosis. Mortalities and delays in rccovcry time in fish sub- jected to galvanonarcosis have probably been a result of exposure to voltage gradients greatcr than the range needed to produce immobilization. Adams et al. (] 972) used voltage gradients of ] .5-3.6 V'cm-1 to narcotize 65-85 mm Notrop;s cornutus for 10-25 s. Fish held in galvanonarcosis did not always recover to an upright position within 120 S, and those that took longer often died. Although Adams ct al. (1972) found a cor- relation between recovery time and energy density, thc voltage gradients were well in excess of those needed to narcotize similar sized fish in our study and in Taylor et al. (1957). Injuries from direct current are probably a direct result of tetanic levels of electricity. This seemed to be the case in Spencer's (1967) and Adams' et al. (1972) studies, since in both studies the voltage gradients were close to 3.5 V'cm-1. Data from our study, Taylor et a1. (1957), Vibert (1963), Ellis (1974), and Kynard and Lonsdale (1957) indicate that direct current gradients below 1.5 V.cm-1 cause no injury to electrically treated fish. The duration of the effects of extended galvano- narcosis on the behavior and physiology of treated fish might be reduced by modifying the electric field applied. Halsband (1955, 1967) reported that treated fish re- covered to normal values of intensity of metabolism within 70 min after galvanonarcosis while average re- covery time for fish treated with condensor charges was 20 min. Thc initial exciting effect an electric current has on the intensity of fish metabolism changes into a paralyzing effect when the period of electrical treat- ment is prolonged as well as when the current density is increased (Halsband, 1955). We have found that fish narcotized up to 3 h by direct currcnt show no sign of behavioral side effects after 24 h. Decreasing the field intensity after fish have reached the galvanonarcosis stage and use of condensor charges might decrease the effects and recovery time of fish immobilized by ex- tended galvanonarcosis and might pCrmit treatments longer than 3 h. Chemicals are often used to immobilize fish for handling but the concentrations nceded to produce narcosis for long periods can be close to lethal levels (Nelson 1953; McParland 1959; Bell 1964). Fish have becn anesthetized up to 12 h with methylparafynol with- out demonstrable long-term effects (McFarland 1959). However, it is not easy to monitor concentrations dur- ing long periods of immobilization, and the state of chcmically induced narcosis can not bc terminated easily if there are complications. Also. chemical anesthetics affect the physiology and behavior of fish (McFarland ] 959; Wedemeyer 1970; Crowley and Berinati ] 972) with some effects lasting up to 5 d after recovery (God- dard et at. 1974). Our study suggests that galvanonarcosis has strong potential as an alternative to chemical anesthetics for long pcriods of fish immobilization. Immobilization techniques are usually cmployed in handling operations such as marking and transport to minimize the chance of injury (Hartley 1967). Galvanonarcosis can be used to safely immobilize fish up to 3 h. There are definite immediate effects on fish behavior that werc not evident in the study of Kynard and Lonsdale (1975) but these were not apparcnt after 24 h. Electricity can be ad- justed and monitored easily so voltages needed to pro-