With man's increasing efforts to live in the world's oceans there is a critical need for reliable protection against one of the undersea world's mostly deadly creatures, the shark.
underwater shots showing various types of sharks swimming about (3 shots).
SV electrode attached to nurse shark to test effects of electricity (7 shots)
CU tiger shark is exposed to electric shock test (3 shots)
SV technician releasing tiger shark (2 shots)
SV technician assembling electric shark dart gun
SV gun is fired into shark
Underwater shot showing shark with dart housing stuck into its back (2 shots)
CU man showing the drogue dart
SV man aims drogue dart at shark and shark swims away with drogue on back (2 shots)
underwater shot showing shark with drogue dart on back swimming with other sharks.
CU the CO2 gas dart being assembled (3 shots)
SV shark hit with gas dart
underwater shot shark being hit with gas dart
SV shark swimming upside down (4 shots)
Initials PS/1324 PS/1404
Script is copyright Reuters Limited. All rights reserved
Background: With man's increasing efforts to live in the world's oceans there is a critical need for reliable protection against one of the undersea world's mostly deadly creatures, the shark. sharks are a potential menace to divers, swimmers and others using the oceans for work or play. Demonstrations by the Naval Undersea Research and Development Centre have shown that shark repellents currently in use are effective. Three new repellents do show promise and are demonstrated in this United States' Department of Defence film.
SYNOPSIS: With man's increasing efforts to work and live in the world's oceans, there is a critical need for protection against these unpredictable creatures - sharks. Demonstrations by Naval Undersea Research and Development Centre in California have shown that present shark repellents are ineffective.
As a result of those findings, United States Navy researchers are trying to develop an effective and easy-to-produce shark - neutralizer. These new prototypes are currently being tested at the centre, and show promise of providing the answer to the shark menace. The new anti-shark devices are; the electric dart, the drogue dart and the carbon dioxide or C-O-two gas dart.
This tiger shark is being exposed to various voltages of electric shock. Researchers discovered that when a shark was exposed to these voltages, its muscles contracted voltages, its muscles contracted violently. Paralysis occurred and the shark remained motionless until the electric current was turned off. As a result of these studies, a self- contained electric dart gun was developed. The unit produces sixty volts for half a second at half second intervals. To be practical, both the size and the cost of the dart must be reduced. At present it is too cumbersome to be carried easily by diver; but as can be seen here, the electric dart gun is highly effective.
The second device being tested is a drogue dart. The unit consist of a sharp dart, or penetrator, attached to a small parachute. The dart is injected into the shark by a lance. It functions as destructor and annoyance to the shark once it has penetrated. After being struck, the shark is mainly interested in ridding himself of the device. The parachute acts as an inhibitor and causes the shark to lose control of its swimming ability.
Although neither the electric dart nor the drogue dart causes immediate or even certain death, use of the third new device will result in death. The C-O-Two dart carries a small container of carbon dioxide gas, which is injected into the body cavity of the shark by means of a lance. Since the shark has no swim bladder, the release of the gas into its body causes it to become buoyant, and die. The major effort of the research centre is to develop effective anti-shark devices that are inexpensive and practical to use. The C-o-Two dart is the most promising so far, as it is small, expendable, and can be produced inexpensively.