Method of controlling the movement of pelagic fish and/or signaling apparatus use therefor

Claim 2

A signalling apparatus for selectively producing an underwater acoustic signal detectable by pelagic fish, said apparatus comprising an amplifier, multi-channel transcribable storage means for storing information corresponding to natural signals which the fish normally associate with feeding and natural signals which the fish normally associate with danger, a transcription unit operable on said transcribable storage means to produce an input signal to said amplifier, selection means for selecting the desired stored inforMation, and a transducer supplied by said amplifier to emit the underwater acoustic signal which may be selected at will either to attract the fish towards the signal source by producing the natural signals which the fish normally associate with feeding or to repel the fish away from the signal source by producing the natural signals which the fish normally associate with danger.

Claim 3

A signalling apparatus as claimed in claim 1, wherein said transcribable storage means comprises a plurality of information channels, each of said channels having two tracks, the natural signals which the fish associate with feeding being recorded on one track and the natural signals which the fish associate with danger being recorded on the other track.

Claim 4

A signalling apparatus as claimed in claim 2, further comprising channel selection means for selecting any one of said plurality of channels.

Claim 5

A signalling apparatus as claimed in claim 3, wherein the natural signals which the fish associate with feeding recorded on one track of each channel are selected from swimming signals of the pelagic fish, noise of feeding birds diving among bait fish, breezing signals of bait fish such as anchovy and combinations of these signals.

Claim 6

A signalling apparatus as claimed in claim 3, wherein the natural signals which the fish associate with danger recorded on the other track of each channel are selected from a low frequency acoustic signal, an acoustic signal produced by the pelagic fish, a noise produced by a tuna when meshed in a gill net, and combinations of these signals.

Claim 9

A signalling apparatus for selectively producing an underwater acoustic signal detectable by pelagic fish, said apparatus comprising an amplifier; multi-channel transcribable storage means for storing information corresponding to natural signals which the fish normally associate with feeding and natural signals which the fish normally associate with danger; a transcription unit operable on said transcribable storage means to produce an input signal to said amplifier; selection means for selecting the desired stored information; and a transducer supplied by said amplifier to emit the underwater acoustic signal which may be selected at will either to attract the fish towards the signal source by producing the natural signals which the fish normally associate with feeding or to repel the fish away from the signal by producing the natural signals which the fish normally associate with danger, said transducer comprising a directional hydrophone projector having a beam width which can be varied between 5* and 90*.

Claim 10

A signalling apparatus for selectively producing an underwater acoustic signal detectable by pelagic fish, said apparatus comprising an amplifier; multi-channel transcribable storage means for storing information corresponding to natural signals which the fish normally associate with feeding and natural signals which the fish normally associate with danger; a transcription unit operable on said transcribable storage means to produce an input signal to said amplifier; selection means for selecting the desired stored information; and a transducer supplied by said amplifier to emit the underwater acoustic signal which may be selected at will either to attract the fish towards the signal source by producing the natural signals which the fish normally associate with feeding or to repel the fish away from the signal by producing the natural signals which the fish normally associate with danger, said transducer comprising a directional hydrophone projector having a beam width which can be varied between 5* and 90*.

Claim 11

A signalling apparatus as claimed in claim 7, wherein said transducer is mounted upon an arm which can be pivotally clamped to a guard rail of a vessel at a controlled depth beneath the surface and having directional indicating means associated with mounting means.