IntroductionTo reduce the unwanted by-catch in shrimp trawling, alternative stimulation techniques such as electricity, which selectively invokes a reaction in shrimp, might be used. The purpose of this study was to evaluate the effects of such electric pulses in sea fish.Materials and MethodsPlaice (n = 21), sole (n = 22), dragonet (n = 21), pogge (n = 21), codfish (n = 20), armed bullhead (n = 14) and fivebeard rockling (n = 8) were exposed to electric pulses (60 V, 0.5 milliseconds, 5 Hz) for 10 sec. Behaviour and mortality were recorded. All fish were killed and subjected to necropsy examination 24 h after exposure. Control animals consisted of equal numbers of the same species not exposed to electric pulses.ResultsAll fish survived the experiment. In almost all exposed fish, minor and brief fright reactions were observed. In general, gross and microscopical abnormalities were rarely present in exposed and control fish. In one control and two electrical-exposed plaice, small multifocal cutaneous haemorrhages were observed. In one electrical-exposed sole, a small focal interstitial haemorrhage in the muscle was present.ConclusionAlternative techniques such as electric pulses for catching shrimp could be promising, since this appears to have low impact on fish, at least under experimental conditions. |
