SHARK-KILLING DEVICE

Nelson Evening Mail, Volume LXIII, 13 July 1929, Page 11

SHARK-KILLING DEVICE

ELECTROCUTION BY WIRES MAKING THE BEACHES SAFE A device which, it is claimed, will make the beaches round about Sydney safe for surfing, was demonstrated before the Chief Secretary of New South Wales, Mr Chaffcy, recently, in tho pond at the Government Fish Hatchery, Gunnamatta Bay. The inventor is Dr. E. G. Moller, a Swedish electrical engineer, and his device consists of two parallel wires, through which _ an electric current is passed, ar.'d is so designed that any large fish passing over them is electrocuted. Some astonishing results were obtained. Sharks of all sizes were experimented with. Unwilling victims, they were goaded across tho dagger zone by men in boats, Who prodded them with rakes. As soon as the current was turned on, the sharks contorted themselves in pain and sank numbed to the bottom, or if at the edge of the zone, raced desperately for safer regions. A 10ft blue whaler, the type that has caused many fatalities on tne beaches, was killed almost, instantly by a charge of twelve volts. After a few shudders, it drifted inert, and was dragged from the pond without difficulty. Dr. Moller claims that a 12-volt charge will be sufficient to kill the largest of sharks. Their bodies aro ready conductors of electricity, while surf'bathers, it has been proved, would not be adversely affected by such a comparatively low voltage. The inventor says that lie believes that the device would be inexpensive to operate, as he judges that- a beach'of the size of Bondi could be made safe against sharks for about 6s an hour. Furthermore, ho says, the wires, being under the surface, would not be affected by the pounding of the surf, and thus repairs would be kept at a minimum. Again, the instrument board would instantly record any defect, and the wires could be taken up and replaced in a few hours. Mr 0. Wood, officer in charge of fisheries, approved the scheme, pointing out that one of .its most interesting aspects was that it did not kill the young fish. A somewhat similar system was in operation iri Japan and America, he 1 said, though it was not used for fish over 3ft in length. So successful was the device in America that the hatcheries there had found it possible to keep apart different varieties of fish in thq one lake.