A device and method for reducing depredation of fish by sharks

Abstract

It is known to try to use electrical currents passed through seawater to deter sharks from regions of human activity. Such high voltages can be dangerous to operators (e.g. fishermen or fishers) when

Claims

1. A device for reducing depredation of fish by sharks, the device comprising:a waterproof housing;a power source within the housing;a first electrode disposed on an exterior of the housing;a first electrically-insulated cage disposed around the first electrode;a second electrode disposed on the exterior of the housing, spaced from the first electrode;a second electrically-insulated cage disposed around the second electrode, the second electrically-insulated cage spaced from the first electrically-insulated cage; anda controller powered by the power source and configured to supply an electrical pulse between the first electrode and the second electrode.

2. The device of claim 1, wherein the controller is configured to supply a sequence of electrical pulses between the first electrode and the second electrode, each electrical pulse in the sequence of electrical pulses spaced from each adjacent pulse by between 0.5 and 2 seconds.

3. The device of claim 2, wherein each electrical pulse has a duration of between 0.5ms and 10ms.

4. The device of any preceding claim, wherein the first electrode is disposed at a first end of the housing; and the second electrode is disposed at a second end of the housing opposite the first end of the housing.

5. The device of any preceding claim, wherein the first cage comprises an enclosure comprising a plurality of elongate members extending from the housing around a periphery of one electrode.

6. The device of claim 5, wherein each elongate member comprises a fin having a length extending away from the housing, a depth extending toward an axis of the device,and a width extending around the axis of the device, and wherein for each fin the length is at least two times greater than the depth, and the depth is at least two times greater than the width.

7. The device of any preceding claim, further comprising a first line attachment eye on the first cage.

8. The device of claim 7, wherein the first eye may be mounted axially on the first cage.

9. The device of claim 7 or claim 8, wherein the first eye is configured to be rotatably connected to the fist cage.

10. The device of claim 9, wherein the first eye comprises a female portion and a male portion releasably insertable therein, and the first eye is configured to form a neck for rotatably engaging with the first cage.

11. A system for reducing depredation of fish by sharks, the system comprising: the device of any preceding claim; and a line attached thereto.

12. A method of reducing depredation of fish by sharks, the method comprising the steps of:providing the device of any one of claims 1 to 10;submerging the device in water; andsupplying an electrical pulse between the first electrode and the second electrode.12

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