Assessment of the humane aspects of electric lancing of whales by measurement of current densities in the brain and heart of dead animals.
The potential physiological effects of the electric lance are assessed, as used in Japanese whaling operations. Current densities are measured in the brains and hearts of six whales to which a controlled current of 5 A is applied by two electrodes inserted at various sites in the carcasses. The whales vary in size from 1.8 m (22 kg) to 16 m (40 t). The minimum current density in the brain necessary to cause depolarisation of neurones is estimated to be 10 mA cm-2 and to cause ventricular fibrillation is estimated to be 0.5 mA cm-2. No current densities exceeding 4.8 mA cm-2 are recorded in the brain. Very few recordings of current density from the heart are above 0.5 mA cm-2, and they occur only when electrodes are in optimal positions. When electrodes are placed as in whaling operations, no whale over 3 m in length would receive current densities in the heart or brain sufficient to cause permanent dysfunction. It is concluded that electric lancing is ineffective as a secondary method of killing whales and that the current densities recorded could cause pain and suffering to an already distressed animal.
Barnes
G R
GR
Department of Physics, Massey University, Palmerston North, New Zealand.
Madie
P
P
Blackmore
D K
DK
D000818:Animals; D001921:Brain / Q000503:physiopathology*; D004556:Electric Injuries / Q000503:physiopathology / Q000662:veterinary*; D004558:Electric Stimulation; D004560:Electricity; D004594:Electrophysiology; D006321:Heart / Q000503:physiopathology*; D014907:Whales / Q000502:physiology*