AU2012351374B2

AU2012351374B2 - Protective device for protecting a fish caught on a hook and fishing system including such a protective device

Info

Publication number: AU2012351374B2
Application number: AU2012351374A
Authority: AU
Inventors: Pascal Bach; Pascal COTEL; Jean-Pierre LAMOUREUX; Njaratiana RABEARISOA
Original assignee: Institut de Recherche pour le Developpement IRD
Current assignee: Institut de Recherche pour le Developpement IRD
Priority date: 2011-12-14
Filing date: 2012-12-11
Publication date: 2016-11-10
Anticipated expiration: 2032-12-11
Also published as: AU2012351374A1; ZA201405082B; FR2984078B1; AP2014007767A0; ES2569194T3; EP2790495A1; WO2013088058A1; FR2984078A1; EP2790495B1

Abstract

The invention relates to a protective device (15) for protecting a fish (2) caught on a hook, said protective device (15) comprising a body (16) and a plurality of elongate protective elements (17), wherein the plurality of protective elements (17) includes first protective elements (17a) having a first buoyancy for being deployed by moving away from the body (16) above the hook and second protective elements (17b) having a second buoyancy, which is less than the first buoyancy, for surrounding the hook.

Description

2012351374 17 Oct 2016 WO 2013/088058 PCT/FR2012/052881 1

Protective device for protecting a fish caught on a hook and fishing system including such a protective device

The invention relates to a protective device for protecting a fish caught on a 5 hook, and a fishing system including such a protective device.

Without being limited to such applications, the invention applies to longline fishing for large pelagic fish such as tuna or swordfish, and can be implemented in a fishing system that comprises: - a line, particularly vertical, or leader, and 10 - at least one hook mounted on the line and possibly baited.

The protective device aims to protect fish caught on the hook from predation by odontoceti (toothed marine mammals) that could find the caught fish either visually or by means of an acoustic signal emitted by the odontoceti (echolocation). 15 A known protective device comprises a body having an axis and a plurality of elongate protective elements each having a first end connected to the body and a free second end, the first ends of the protective elements being distributed around the axis of the.

The invention aims to improve the protection for the caught fish. 20 According to one form of the present invention, there is provided protective device for protecting a fish caught on a hook from predation by odontoceti that could find the caught fish either visually or by means of an acoustic signal reflected in response to an acoustic signal emitted by the odontoceti, said protective device comprising a body having an axis (A) and a plurality of elongate protective 25 elements each having a first end connected to the body and a free second end, the first ends of the protective elements being distributed about the axis (A) of the body, wherein the plurality of protective elements comprises: - first protection elements having a first buoyancy, said first protective elements being adapted to deploy outward from the body above the hook, and 30 - second protective elements having a second buoyancy that is less than the first buoyancy, said second protective elements being adapted to surround the hook. 2012351374 17 Oct 2016 WO 2013/088058 PCT/FR2012/052881 2

Thus, one form of the protective device of the invention combines two levels of protection for the captured fish: a visual protection consisting of the first protective elements floating above the hook and caught fish in order to scare away the odontoceti, and a visual and physical protection consisting of the second 5 protective elements which surround the fish to reduce accessibility and hide it visually.

In particular, the first buoyancy can be adapted to allow the first protective elements to extend substantially perpendicularly to the axis of the body and the second buoyancy can be adapted to allow the second protective elements to 10 extend substantially parallel to the axis of the body.

The first protective elements may have a positive buoyancy and the second protective elements may have a negative buoyancy.

The first protective elements may be flexible strips, in particular of plastic.

The second protective elements may be chains of rings, in particular of 15 metal.

Advantageously, the protective device may further comprise a plurality of acoustic reflection targets which are each attached to one of the protective elements and are adapted to modify the reflected acoustic signal.

The protective device thus combines the two previously mentioned levels of 20 protection for the caught fish with a third level of protection: the acoustic protection formed by the acoustic reflection targets which hides the fish from acoustic identification by echolocation.

The acoustic reflection targets can be attached to the first protective elements, particularly at the second ends of the first protective elements. 25 The acoustic reflection targets may be hollow balls with positive buoyancy.

The body may have a base intended to be placed next to the hook, the first ends of the first protective eiements may be arranged substantially in at least a first plane that is radial to the axis of the body, and the first ends of the second protective elements may be arranged substantially in at least a second plane that 30 is radial to the axis of the body, the first plane being located at a greater distance from the base of the body than the second plane. 2012351374 17 Oct 2016 WO 2013/088058 PCT/FR2012/052881 3

According to a second aspect, the invention proposes a fishing system for catching fish, comprising: - a line, - at least one hook mounted on the line, and 5 - at least one protective device as defined above, the protective device being mounted on the line.

The protective device may be movable between: a rest position in which the body is at a distance from the hook; and an active position in which the body is close to the hook, the first protective elements are deployed outward from the body 10 above the hook, and the second protective elements surround the hook.

The fishing system may further comprise an automatic activation device adapted to transition the protective device from the rest position to the active position when traction is exerted by a fish on the line during the capture of said fish on the hook. 15 In particular, the automatic activation device may comprise a retaining means suitable for retaining the protective device in the rest position and for releasing the protective device when traction is exerted on the line, the protective device having negative buoyancy overall and being slidably mounted on the line.

The retaining means may, for example, be a shell placed at a distance from 20 the hook and suitable for retaining the protective device when in the closed state, and for releasing the protective device when in the open state.

The shell containing the protective device can easily be installed when in fishing areas frequented by odontocetis. The shell opens when traction is exerted on the line by a fish caught on the hook, releasing the protective device. 25 Other features and advantages of the invention will be apparent from reading the following description of a particular embodiment of the invention, given by way of non-limiting example, this description being made with reference to the accompanying drawings in which: - figure 1 is a representation of a fishing system comprising a protective 30 device according to one embodiment of the invention, placed in a shell and in a rest position away from the hook, 2012351374 17 Oct 2016 WO 2013/088058 PCT/FR2012/052881 4 - figure 2 is a representation of the fishing system of figure 1, illustrating the protective device in an active position close to the hook, the first protective elements provided with acoustic reflection targets being deployed above the fish caught on the hook, and the second protective elements covering an essential part 5 of the fish caught on the hook.

In the figures, the same references denote identical or similar elements.

Figures 1 and 2 show a fishing system 1 that can be used in longline fishing to catch large pelagic fish 2 whose weight can range from 20 kg to 200 kg, such as tuna or swordfish. 10 The fishing system 1 comprises one or more hooks 5 mounted on a fishing

Sine. In the specific application of longline fishing, leaders 4, which may range from 100 to 1500 in number, are regularly distributed along a main line, not shown, which can be a single nylon filament about 3 mm to 4 mm in diameter and of a length which can be between 15 km and 120 km. The leaders 4 consist, for 15 example, of single nylon filaments about 2 mm in diameter and equipped at the free end with one of the hooks 5, generally with bait 6.

For each of the leaders 4, a protective device 15 is provided to protect the fish 2 caught on the hook 5 from predation by odontoceti, which are toothed marine mammals such as pilot whales or false killer whales that identify a fish 2 20 caught on the hook 5 either visually or by echolocation (relying on acoustic signals that are reflected in response to acoustic signals emitted by the odontoceti).

As represented in figure 2, the protective device 15 comprises a body 16, for example cylindrical about an axis A, rigid, and designed of a material with high negative buoyancy. The body 16 has a base next to the hook 5. The protective 25 device 15 also includes a plurality of protective elements 17. The protective elements 17 are connected to the body 16 by respective fixed first ends 18 that extend to respective free second ends 19.

In particular, the protective elements 17 comprise first protective elements 17a and second protective elements 17b having respective buoyancies chosen so 30 that the first protective elements 17a deploy outward from the body 16 above the hook 5, and the second protective elements 17a surround the hook 5. 2012351374 17 Oct 2016 WO 2013/088058 PCT/FR2012/052881 5 !n the embodiment represented, the first protective eiements 17a have a first buoyancy that is positive, and are in the form of rectangular, flexible, and deformable plastic strips. The strips 17a have their respective first ends 18 distributed around the axis A of the body 16, substantially in one or more first 5 planes P1 that are radiai to the axis A of the body 16. In addition, each strip 17a may have a length between its first 18 and second 19 ends that is greater than 1 m, in particular about 1.50 m.

The second protective eiements 17b have a second buoyancy that is less than the first buoyancy, in particular a negative buoyancy, and are, in the particular 10 embodiment represented, in the form of chains of rings which may be of metal. The chains 17b have their respective first ends 18 distributed around the axis A of the body 16 substantially in one or more second planes P2 that are radiai relative to the axis A of the body 16. The first planes P1 are placed at distances from the base of the body 16 and therefore from the hook 5 that are greater than 15 those of the second planes P2. in addition, each chain 17b may have a length between its first 18 and second 19 ends that is greater than 1 m, in particular about 1.20 m.

The protective device 15 further comprises balls 20 that are respectively attached to the strips 17a. The balls 20 each have a spherical outer surface and 20 thus constitute acoustic reflection targets that modify, by amplifying, the acoustic signal reflected in response to the acoustic signal emitted by odontoceti. The invention is not limited to the creation of acoustic reflection targets in the form of balls. Any other acoustic reflection target having a curved outer surface or any other characteristic that modifies the reflected acoustic signal could be 25 used. Furthermore, in other embodiments, acoustic reflection targets could be provided on the second protective elements 17b.

The balls 20 may also be arranged to give the strips 17a positive buoyancy. In particular, hollow balls 20 are attached to the free ends 19 of the strips 17a and provide positive buoyancy. 30 The invention is not limited to the protective elements described above. The differences in buoyancy between the first protective elements 17a and the second protective elements 17b can arise from their respective structures or from the 2012351374 17 Oct 2016 WO 2013/088058 PCT/FR2012/052881 6 materials used. Other structures and other materials may therefore be used to obtain the required buoyancy characteristics. Differences in buoyancy could also be induced by the arrangement of balls or other ballast elements, possibly of different types, on the first 17a and second 17b protective eiements. 5 As is visible in figures 1 and 2, the protective device 15 can be moved along the leader 4 between a rest position represented in figure 1 and an active position represented in figure 2.

In the rest position, the body 16 of the protective device 15 is distanced from the hook 5 to allow catching a fish 2 on the hook 5, said hook possibly with 10 bait 6 to improve effectiveness. It may be stored in a shell 25, in a closed state, attached to the fishing line 4.

When traction is exerted on the hook 5 by the fish 2 during its capture, this traction can be transmitted to the leader 4 to activate an automatic activation device that causes the protective device 15 to transition from the rest position 15 (figure 1) to the active position (figure 2).

In the embodiment represented, the automatic activation device has caused the shell 25 to transition from the closed state to an open state. The shell 25 is a locking means which when in the closed state retains the protective device 15 in the rest position, and when in the open state releases the protective device 20 15. Due to the negative buoyancy of the body 16 and the chains 17b when the shell 25 is in the open state, the protective device 15 is able to slide along the leader 4 into the active position.

In the active position, the body 16 is outside the shell 25, near the hook 5. The strips 17a, which are unweighted, deploy outward from the body 16 above 25 the hook 5 and the fish 2 caught on the hook 5. In the embodiment represented, the buoyancy of the strips 17a is such that the strips 17a float substantially horizontally, perpendicular to the axis A of the body 16. The chains 17b, with their negative buoyancy, extend substantially parallel to the axis A of the body 16, surrounding the hook 5 and covering at least an essential part of the fish 2 caught 30 on the hook 5.

The balls 20 protect the fish 2 from echolocation by odontoceti whose ability to locate the fish is reduced due to the modification of the reflected acoustic 2012351374 17 Oct 2016 WO 2013/088058 PCT/FR2012/052881 7 signal. The chains 17b provide a visual and physical protection for the fish 2 by forming a barrier around the fish 2. Lastly, the strips 17a provide another level of visual protection for the fish 2 against odontoceti by alarming them and keeping them at a distance. 5 In the ciaims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in 10 various embodiments of the invention. it is to be understood that, if any prior art pubiication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country. 15

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. Protective device for protecting a fish caught on a hook from predation by odontoceti that could find the caught fish either visually or by means of an acoustic signal reflected in response to an acoustic signal emitted by the odontoceti, said protective device comprising a body having an axis (A) and a plurality of elongate protective elements each having a first end connected to the body and a free second end, the first ends of the protective elements being distributed about the axis (A) of the body, wherein the plurality of protective elements comprises: - first protection elements having a first buoyancy, said first protective elements being adapted to deploy outward from the body above the hook, and - second protective elements having a second buoyancy that is less than the first buoyancy, said second protective elements being adapted to surround the hook.
2. Protective device according to claim 1, wherein the first buoyancy is adapted to allow the first protective elements to extend substantially perpendicularly to the axis (A) of the body and the second buoyancy is adapted to allow the second protective elements to extend substantially parallel to the axis (A) of the body.
3. Protective device according to claim 1 or 2, wherein the first protective elements have a positive buoyancy and the second protective elements have a negative buoyancy.
4. Protective device according to any one of claims 1 to 3, wherein the first protective elements are flexible strips.
5. Protective device according to claim 4 in which the flexible strips are plastic flexible strips.
6. Protective device according to any one of claims 1 to 5, wherein the second protective elements are chains of rings.
7. Protective device according to claim 6 in which the chains of rings are metal chains of rings.
8. Protective device according to any one of claims 1 to 7, further comprising a plurality of acoustic reflection targets which are each attached to one of the protective elements and are adapted to modify the reflected acoustic signal.
9. Protective device according to claim 8, wherein the acoustic reflection targets are attached to the first protective elements.
10. Protective device according to claim 9 in which the acoustic reflection targets are attached at the second ends of the first protective elements.
11. Protective device according to claim 8, wherein the acoustic reflection targets are hollow balls with positive buoyancy.
12. Protective device according to any one of claims 1 to 11, wherein the body has a base intended to be placed next to the hook, the first ends of the first protective elements are arranged substantially in at least a first plane (P1) that is radial relative to the axis (A) of the body, and the first ends of the second protective elements are arranged substantially in at least a second plane (P2) that is radial to the axis (A) of the body, the first plane (P1) being located at a greater distance from the base of the body than the second plane (P2).
13. Fishing system for catching fish, comprising: - a line, - at least one hook mounted on the line, and - at least one protective device according to any one of claims 1 to 12, the protective device being mounted on the line.
14. Fishing system according to claim 13, wherein the protective device is movable between: a rest position in which the body is at a distance from the hook; and an active position in which the body is close to the hook, the first protective elements are deployed outward from the body above the hook, and the second protective elements surround the hook.
15. Fishing system according to claim 13 or 14, further comprising an automatic activation device adapted to transition the protective device from the rest position to the active position when traction is exerted by a fish on the line during the capture of said fish on the hook.
16. Fishing system according to claim 15, wherein the automatic activation device comprises a retaining means suitable for retaining the protective device in the rest position and for releasing the protective device when traction is exerted on the line, the protective device having negative buoyancy overall and being slidably mounted on the line.
17. Fishing system according to claim 16, wherein the retaining means is a shell placed at a distance from the hook and suitable for retaining the protective device when in a closed state, and for releasing the protective device when in an open state.