Some observations on the narcotizing ability of electric currents on the common carp Cyprinus carpio.

Some effects of alternating current electronarcosis and of rectified current electronarcosis on C. carpio were investigated. In all instances recovery from narcosis was accompanied by convulsive spasms. Haemorrhaging of the gills was also observed to occur. Carp do not appear to be suitable candidates for electronarcosis.

The use of electronarcosis as anaesthetic in the cichlid, Oreochromis mossambicus (Peters). III. The effects of changing physical and electrical parameters on the narcotizing ability of half-wave rectified currents.

The narcotizing potential of various rectified current configurations on Oreochromis mossambicus was investigated. A 50 Hz, 200 Vp. half-wave rectified current, applied for 30 s, was found to be a suitable configuration for electronarcosis.

The use of electronarcosis as anaesthetic in the cichlid, Oreochromis mossambicus (Peters). II. The effects of changing physical and electrical parameters on the narcotizing ability of alternating current.

The effects of wave form, voltage, frequency and current as well as application time on the narcotizing ability of alternating current were investigated. A 60 Vrms, 50 Hz sine wave current applied for 30 s produced narcosis of sufficient duration to enable handling and blood sampling. A triangle wave form was inferior in narcotizing ability to both sine wave and square wave forms. Duration of narcosis increased with increasing water conductivity but was reduced by increasing water temperatures.

The use of electronarcosis as anaesthetic in the cichlid, Oreochromis mossambicus (Peters). I. General experimental procedures and the role of fish length on the narcotizing effects of electric currents.

Procedures to narcotize fish by means of alternating or direct electrical currents are described and a method of evaluating the narcotic effects on fish of electrical currents is detailed. The role of fish length on the narcotizing potential of electrical currents was investigated. The results indicate that there is a positive correlation between fish length and the duration of narcosis.

Some observations on the influence of stress on ECG patterns in Oreochromis mossambicus and Cyprinus carpio.

Electrocardiograms of undisturbed, resting fish as well as disturbed (stressed) fish were recorded by biotelemetry. Both fish species showed marked changes in heartbeat patterns in response to stress with tilapia exhibiting the most pronounced changes. A theory is advanced to account for the marked changes in electrocardiogram patterns of disturbed fishes.