WO2008143582A1

WO2008143582A1 - Fish trap

Info

Publication number: WO2008143582A1
Application number: PCT/SE2008/050579
Authority: WO
Inventors: Christer Lundin
Original assignee: Christer Lundin
Priority date: 2007-05-22
Filing date: 2008-05-16
Publication date: 2008-11-27
Also published as: SE0701215L; SE531185C2

Abstract

The invention relates to a fish trap comprising: - a first chamber (10), in which fishes swimming into the fish trap are intended to be confined; - a second chamber (40), through which fishes are intended to pass on their way to said first chamber; - a blocking device (60) which is arranged to block the exit opening of the second chamber in such a manner that seals are prevented from passing but fishes are allowed to pass through this exit opening in the direction towards the first chamber; - a closing device (70) for closing the entrance opening of the second chamber; - a manoeuvring device (80) connected to the closing device, by means of which the closing device is manoeuvrable from open position to closed position; and - an activation device (90) connected to the manoeuvring device, which activation device is arranged, by the influence from a seal in the second chamber, to activate the manoeuvring device to manoeuvre the closing device from open position to closed position so as to thereby achieve confinement of the seal in the second chamber.

Description

Fish trap

FIELD OF THE INVENTION AND PRIOR ART

The present invention relates to a fish trap comprising: - a chamber formed with walls of net, here denominated first chamber, in which fishes swimming into the fish trap are intended to be confined, this first chamber having an entrance opening designed to allow passage of fishes into this chamber; - a chamber formed with walls of net, here denominated second chamber, through which fishes swimming into the fish trap are intended to pass on their way to said first chamber, this second chamber having an entrance opening designed to allow passage of fishes and seals into this chamber and an exit opening connected to the entrance opening of said first chamber; and - a blocking device arranged at the exit opening of said second chamber, which blocking device is arranged to block the exit opening in such a manner that seals are prevented from passing but fishes are allowed to pass through this exit opening in the direction towards said first chamber.

When fishing with fixed fishing gear in the form of nets and fish traps, so-called hoop nets and the like, in areas with presence of seal, it frequently occurs that seals attack the fishes caught in the fishing gear before there has been any time to search and empty the fish gear. Such seal attacks may cause costly damages to the caught fishes. Furthermore, a seal that is in or in the vicinity of a fishing gear may scare away fish approaching the fishing gear and thereby reduce the catch.

A fish trap of the above-mentioned type is previously known from SE 522 950 C2. In connection with the use of this previ- ously known fish trap, it has turned out that it has been possible to protect the fishes confined in this fish trap very well against attacks from seals. However, the problem with a reduced catch due to seals being in the vicinity of the fish trap remains when using this previously known fish trap. The last-mentioned problem can be taken care of by shooting seals. However, it has turned out to be difficult to carry on seal hunting in an efficient manner with the existing hunting regulations.

OBJECT OF THE INVENTION

The object of the present invention is to achieve a further development of a fish trap of the type mentioned by way of introduction so as to make possible a reduction of the problem with seals that are staying in or in the vicinity of the fish trap.

SUMMARY OF THE INVENTION

According to the present invention, said object is achieved by means of a fish trap having the features defined in claim 1.

The fish trap according to the invention comprises:

- a chamber formed with walls of net, here denominated first chamber, in which fishes swimming into the fish trap are in- tended to be confined, this first chamber having an entrance opening designed to allow passage of fishes into this chamber;

- a chamber formed with walls of net, here denominated second chamber, through which fishes swimming into the fish trap are intended to pass on their way to said first chamber, this second chamber having an entrance opening designed to allow passage of fishes and seals into this chamber and an exit opening connected to the entrance opening of said first chamber;

- a blocking device arranged at the exit opening of said second chamber, which blocking device is arranged to block the exit opening in such a manner that seals are prevented from passing but fishes are allowed to pass through this exit opening in the direction towards said first chamber;

- a closing device which is manoeuvrable from an open position, in which the closing device keeps the entrance opening of said second chamber open and allows passage of fishes and seals through this entrance opening, to a closed position, in which the closing device keeps this entrance opening closed and thereby prevents seals from passing through this entrance opening out of the second chamber; - a manoeuvring device connected to the closing device, by means of which manoeuvring device the closing device is manoeuvrable from its open position to its closed position; and

- an activation device connected to the manoeuvring device, which activation device is arranged, by the influence from a seal in the second chamber, to activate the manoeuvring device to manoeuvre the closing device from its open position to its closed position so as to thereby achieve confinement of the seal in the second chamber.

By means of the fish trap according to the invention, it will be possible, in a manner that is acceptable from the view point of prevention of cruelty to animals, to catch a seal that swims into the fish trap in order to try to get hold of fishes confined therein, at the same time as the caught seal is prevented from getting hold of these fishes. In connection with the searching and emptying of the fish trap, the seal confined therein may then be shot and taken care of in a suitable manner. By the use of the fish trap according to the invention, it will be possible in course of time to reduce the seal population in the fishing area in question and thereby enable an improved fish catch.

Preferred embodiments of the fish trap according to the invention will appear from the dependent claims and the following description. BRIEF DESCRIPTION OF THE DRAWINGS

The invention will in the following be more closely described by means of embodiment examples, with reference to the appended drawings. It is shown in:

Fig 1 a longitudinal section through a fish trap according to a first embodiment of the present invention, with the closing device of the fish trap shown in open position and with certain parts of the fish trap shown in detail enlargements,

Fig 2 a longitudinal section through the fish trap according to Fig 1 , with the closing device of the fish trap shown in closed position and with certain parts of the fish trap shown in detail enlargements,

Fig 3 a longitudinal section through the fish trap according to Fig 1 , with the closing device of the fish trap shown in open position and with the manoeuvring device of the fish trap shown in a detail enlargement,

Fig 4 a longitudinal section through a part of a fish trap according to a second embodiment of the invention, with the closing device of the fish trap shown in open position and with the manoeuvring device of the fish trap shown in a detail enlargement,

Fig 5 a frontal view of the closing device of the fish trap according to Fig 4 shown in closed position,

Fig 6 a longitudinal section through a part of a fish trap according to a third embodiment of the invention, with the closing device of the fish trap shown in open po- sition and with the manoeuvring device of the fish trap shown in a detail enlargement, and Fig 7 a frontal view of the closing device of the fish trap according to Fig 6 shown in closed position.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Figs 1-3 illustrate a fish trap 1 according to a first embodiment of the present invention intended to be placed in a pool of water, for instance in the form a sea, a lake or a river, in order to catch fish. The fish trap may for instance be dimensioned for catching salmon or whitefish.

The fish trap 1 comprises a chamber 10 formed with walls 1 1 of net, here denominated first chamber, in which fishes swimming into the fish trap 1 are intended to be confined. This first chamber 10 has an entrance opening 12 which is designed to allow passage of fishes into this chamber.

The net walls 1 1 of the first chamber are attached to a frame 20, which is mounted on two or more pontoons 21 , for instance in the manner more closely described in SE 522 950 C2. These pontoons 21 can, through a hose (not shown), be filled with or emptied off gas or a gas mixture, such as for instance air, so as to thereby regulate the buoyancy of the pontoons. By filling a gas or gas mixture into the pontoons 21 , the buoyancy of the pontoons may be increased so that the pontoons will lift the frame 20 and the first chamber 10 carried by the frame over the surface of the water so as to thereby facilitate a searching and emptying of the fish trap. In the illustrated example, the pon- toons 21 have such a design that they will move upwards with one end 21 a (the left end in Figs 1-3) inclined upwards in relation to the other end 21 b when they are being filled with gas or gas mixture. Hereby, the fishes confined in the first chamber 10 will be gathered in a trough 13 in the rear part of the first cham- ber 10 when the first chamber under the action of the pontoons 21 is lifted up over the surface of the water. The stern or stem of a boat may then be moved in under the trough 13, whereupon the fishes gathered in the trough may be emptied down into the boat through an openable door 14 in the trough. The pontoons 21 have flexible walls, and by releasing the gas or gas mixture pumped into the pontoons, the walls are compressed by the pressure from the surrounding volume of water and thereby loose buoyancy so that the frame 20 and the first chamber 10 will sink back downwards in the pool of water where the fish trap is placed.

The frame 20 comprises a number of rigid rings 22, for instance of metal, which are arranged at a distance from each other in the longitudinal direction of the frame and to which the net walls 1 1 of the first chamber are attached by means of lines (not shown). The net walls 1 1 are kept stretched by these lines. In the illustrated example, the fish trap 1 comprises a protecting device 30 formed by a net section 31 , which protecting device surrounds the first chamber 10 in order to prevent seals from getting hold of, from the outside of the first chamber, fishes confined in the first chamber. This net section 31 is of a strong material so as to withstand attacks from seals. Also this net section 31 is attached to said rings 22 of the frame and is kept stretched by these rings at a distance from the net walls 1 1 of the first chamber. In the illustrated example, the frame 20 also comprises inclined rods 23 and longitudinal rods 24, 25, 26 for keeping the rings 22 spaced from each other and reinforcing the frame.

The fish trap 1 further comprises a chamber 40 formed with walls 41 of net, here denominated second chamber, through which fishes swimming into the fish trap 1 are intended to pass on their way to the first chamber 10. The second chamber 40 has an entrance opening 42 designed to allow passage of fishes and seals into this chamber and an exit opening 43 connected to the entrance opening 12 of the first chamber 10. In the illustrated example, the exit opening 43 of the second chamber 40 coincides with the entrance opening 12 of the first chamber 10, but these openings could alternatively be arranged at a distance from each other and possibly connected with each other through a further chamber arranged between the first chamber and the second chamber.

The second chamber 40 is at its rear end delimited by a cornet- shaped net section 45, which is connected to the exit opening 43 and which in the illustrated example also delimits the front end of the first chamber 10. At its broader end the net section 45 is attached to the foremost ring 22 of the frame 20 and it is kept stretched in the radial direction by this ring. In the longitudinal direction of the fish trap, the net section 45 is kept stretched by means of lines 46, which are attached to the nar- rower end of the net section 45 about the exit opening 43 and which in the illustrated example converge towards a common attachment 47 in the form of a ring or the similar located in the centre of the first chamber 10. This attachment 47 is kept in place by means of lines 48 extending between the attachment and the rearmost ring 22 of the frame 20. The net section 45 is narrowing in the direction towards the first chamber 10.

The second chamber 40 is delimited in the radial direction by a cylinder-shaped net section 49, which in the illustrated example is formed in one piece with the net section 31 that forms the above-mentioned protecting device 30 around the first chamber 10. The net section 49 is attached to the foremost ring 22 of the frame 20 and to a number of other rigid rings 50, for instance of metal, which are arranged at a distance from each other in the longitudinal direction of the second chamber and which keeps the net section 49 stretched in the radial direction.

The second chamber 40 is at its front end delimited by a cornet- shaped net section 51 , which is connected to the entrance opening 42. This net section 51 is at its broader end attached to one of said rings 50 and is kept stretched in the radial direction by this ring. In the longitudinal direction of the fish trap, the net section 51 is kept stretched by means of lines 53, which are attached to the narrower end of the net section 51 about the entrance opening 42 and which in the illustrated example diverge in the direction towards another of said rings 50, to which these lines 53 are attached. The net section 51 is narrowing in the direction towards the first chamber 10.

The illustrated fish trap 1 constitutes a so-called fish house and is at its front end 1 a intended to be connected to a so-called trap part, which is intended to direct fishes into the fish trap 1 , as more closely described in SE 522 950 C2. The cylinder- shaped net section 49 is kept stretched in the longitudinal direction of the fish trap by its attachment to the trap part.

A blocking device 60 is arranged at the exit opening 43 of the second chamber. This blocking device is arranged to block the exit opening 43 in such a manner that seals are prevented from passing but fishes are allowed to pass through this exit opening and further on into the first chamber 10. In the illustrated exam- pie, the blocking device comprises a rigid frame-shaped element 61 , for instance of metal, which has a central opening 62 coinciding with the exit opening 43 of the second chamber. The blocking device 60 further comprises an elongated blocking member 63, preferably in the form of a line or wire, which is fastened to said frame-shaped element 61 and extends across the central opening 62 of this element while dividing this opening into two smaller opening areas 62a, 62b. The respective opening area 62a, 62b is to have such a size that the fishes that are intended to be caught by means of the fish trap may pass through the opening area without any inconvenience at the same time as seals are prevented from forcing their way through the opening area. When necessary, for instance in order to prevent otters or other fish-eating predatory animals of smaller size to force their way into the first chamber, two or more blocking members could be arranged to extend across the central opening of the frame-shaped element 61 for a suitable adaptation of the size of the remaining opening areas. The frame-shaped element 61 and the blocking member 63 are to be dimensioned strong enough to withstand attacks from seals. In the illustrated example, the frame-shaped element 61 is rectangular, but it could also have other polygon shape or be circular.

The fish trap 1 further comprises a closing device 70 which is manoeuvrable from an open position (see Fig 1 ), in which the closing device keeps the entrance opening 42 of the second chamber 40 open and allows passage of fishes and seals through this entrance opening, to a closed position (see Fig 2), in which the closing device keeps the entrance opening 42 closed and thereby prevents the seals from passing through this entrance opening out of the second chamber 40. When the closing device 70 is in its closed position, a seal being in the second chamber 40 will consequently be confined in the second chamber, since the closing member prevents it from swimming back out of the second chamber 40 through the entrance opening 42 at the same time as the blocking device 60 prevents it from swimming further on into the first chamber 10.

The closing device 70 is connected to a manoeuvring device 80, by means of which the closing device 70 is manoeuvrable from its open position to its closed position. This manoeuvring device 80 is in its turn connected to an activation device 90, which is arranged, by the influence from a seal in the second chamber 40, to activate the manoeuvring device 80 to manoeuvre the closing device 70 from its open position to its closed position so as to thereby achieve confinement of the seal in the second chamber. The activation device 90 comprises an activation member 91 (see Fig 2), which is connected to the blocking device 60 and which is arranged to be influenced and thereby activate the manoeuvring device 80 when a seal trying to pass through the exit opening 43 of the second chamber bumps into the blocking device. In the illustrated example, the activation device 90 comprises a holder 92 formed as a rigid frame about the exit opening 43 of the second chamber, to which holder the frame-shaped element 61 of the blocking device is hingedly attached through a pivotal joint 93 (see Fig 2) so as to allow the frame-shaped element 61 to turn in relation to the holder 92 when a seal trying to pass through the exit opening 43 of the second chamber bumps into the blocking member 63 of the blocking device. The frame- shaped element 61 is only tumable a short distance in relation to the holder 92, from the position illustrated in Fig 1 to the position illustrated in Fig 2, so that a seal is prevented from passing through the gap 95 between the frame-shaped element 61 and the holder 92. The above-mentioned cornet-shaped net section 45 is at its narrower end attached to the holder 92 and the central opening of the holder consequently forms the exit opening 43 of the second chamber 40. The holder 92 has essentially the same shape as the frame-shaped element 61.

In the illustrated example, the activation device 90 further com- prises a tube-shaped jacket 94 in the form of a flexible hose, which at one of its ends is attached to said holder 92 and at its other end is attached to an attachment 81 that is fixedly connected to the manoeuvring device 80. In this case, the activation member 91 is an elongated traction transmitting element in the form of a line or wire, which displaceably extends through the tube-shaped jacket 94 and which at one of its ends is attached to a release member 82 of the manoeuvring device 80 and at its other end is attached to the frame-shaped element 61 or the blocking member 63 of the blocking device. The activation member 91 is arranged to be displaced a given distance in relation to the jacket 94 and thereby exert a traction on the release member 82 when the blocking device 60 is turned in relation to the holder 92 under the action of a seal that bumps into the blocking member 63 of the blocking device when trying to pass through the exit opening 43 of the second chamber. Said release member 82 is movable in relation to the attachment 81 and is under the action of the activation member 91 manoeuvrable from a rest position (see Fig 1 ) to a release position (see Fig 2) for activation of the manoeuvring device 80. The manoeu- vring device 80 is with advantage a gas spring, as illustrated in Figs 1-3, with a cylinder 83 and a piston with a piston rod 84, which piston is received in the cylinder and displaceable in relation to the cylinder. In this case, the release member 82 is arranged to open a valve device 85 of the gas spring when being activated, so that the piston rod 84 under the action of a compression force acting on the piston of the gas spring thereby is made to be displaced in the direction out of the cylinder 83. In the illustrated example, the gas spring is attached to one of said rings 50 and its release member 82 consists of a lever which is hingedly attached to the valve device 85. A stop member 86, hingedly connected to the release member 82, is arranged to retain the release member in the release position after an activation of the manoeuvring device, as illustrated in Fig 2.

In the example illustrated in Figs 1-3, the closing device 70 comprises two rigid and elongated closing elements 71 , 72 (see Fig 1 ), which are arranged in parallel with and opposite each other on opposite sides of the entrance opening 42 of the second chamber 40. These closing elements 71 , 72 are attached to the narrower end of the above-mentioned cornet-shaped net section 51 and are under the action of a traction from the manoeuvring device 80 displaceable towards each other in order to close the entrance opening 42 of the second chamber. In the open position (see Fig 1 ), the closing elements 71 , 72 are kept at a distance from each other under the action of elastic members 73, which are connected to a respective one of the above- mentioned lines 53 that are keeping the net section 51 stretched in the longitudinal direction of the fish trap. The respective elastic member 73 may for instance be a draw spring or an elastic string and is mounted so as to extend between a point 74 on the associated line 53 and the ring 50 to which the line is attached. When the closing device is in its open position (see Fig 1 ), the parts 53a of the lines 53 extending in parallel with the elastic members 73 are kept slack and these line parts 53a will be extended to their full length when the closing device is made to assume its closed position, as illustrated in Fig 2. In this manner, a limited displacement of the closing elements 71 , 72 is allowed when the closing device is manoeuvred from open position to closed position, at the same time as the elastic members 73 make the closing elements 71 , 72 separate from each other so as to thereby open up the entrance opening 42 when the traction exerted by the manoeuvring device 80 is made to cease in connection with the restoration of the fish trap after the confinement of a seal in the second chamber 40.

In the example illustrated in Figs 1-3, the closing device 70 comprises two tube-shaped jackets 75 in the form of flexible hoses, which at one of their ends are attached to a respective end of one 71 of the closing elements and at their other end are attached to an attachment 81 that is fixedly connected to the manoeuvring device 80. Two elongated traction transmitting elements 76 in the form of lines or wires extend displaceably through a respective one of said jackets 75 and are at one of their ends attached to a respective end of the second closing element 72 and at their other end attached to a drawing member of the manoeuvring device 80, which drawing member here is formed by the above-mentioned piston rod 84.

When the fish trap is to be used, the release member 82 is positioned in its rest position, which is illustrated in Fig 1 , and the gas spring is preloaded by pressing the piston rod 84 into the cylinder 83 while compressing the gas confined therein. The preloading of the gas spring may for instance be done by means of a winch 87 (see Fig 3), which is fixedly connected to the cylinder 83 and which has a pulling rope or pulling wire 88 fastened to the outer end of the piston rod 84. This winch 87 may for instance be manoeuvred manually by means of a crank 89. The draw spring is retained in its preloaded state by means of the valve device 85. When the draw spring is preloaded, the traction exerted on the closing element 72 by the traction transmitting elements 76 ceases and the closing elements 71 , 72 are sepa- rated from each other under the action of the spring force from the elastic members 73 so that the entrance opening 42 of the second chamber 40 is opened up.

By releasing air from the pontoons 21 the fish trap 1 is lowered down into the water on the fishing place in question. The fish trap 1 is lowered to such a depth that the entrance opening 42 and the exit opening 43 of the second chamber 40 and the entrance opening 12 of the first chamber 10 at least to the major part are located under the surface of the water. In order to pre- vent seals from getting drowned when being confined in the second chamber 40, the fish trap 1 is after the lowering to be located in such a position that the upper part of the second chamber 40 is above the surface of the water. This may for instance be secured by means of floats (not shown), such as buoys or the like, which are attached to one or more of said rings 22, 50, for instance through lines. Fishes can now swim into the first chamber 10 through the second chamber 40. A seal wanting to get hold of fishes confined in the first chamber 10 can swim into the fish trap through the entrance opening 42 of the second chamber. When this seal thereafter tries to force its way into the first chamber 10 through the exit opening 43 of the second chamber, the seal will bump into the blocking member 63 of the blocking device 60 and thereby cause a turning of the frame-shaped element 61 in relation to the holder 92, whereupon the activation member 91 is displaced and made to exert a traction on the release member 82, which in its turn is made to turn from its rest position to its release position by this traction and thereby achieves an opening of the valve device 85. When the valve device 85 is opened, the piston rod 84 of the gas spring will be pushed out and pull the traction transmitting elements 76 with it, which traction transmitting elements in their turn will be displaced in relation to their jackets 75 and thereby exert a traction on the closing element 72 so that the closing elements 71 , 72 are displaced towards each other against the action of the spring force from the elastic members 73 so as to thereby close the entrance opening 42 of the second chamber, so that the seal is confined in the second chamber 40. The entrance opening 42 is kept closed by the closing elements 71 , 72 until the gas spring is preloaded once again. The fish trap 1 can be lifted up to the surface in order to be searched and emptied by pumping air into the pontoons 21 . The seal confined in the second chamber 42 may be shot and the dead seal can thereafter be brought out through the entrance opening 42 after the opening of the entrance opening by means of a new preloading of the gas spring. The fish trap is then ready to be low- ered down once again to the intended depth for continued fishing.

Figs 4-7 illustrate two different embodiments of a fish trap according to the present invention where the closing device 170 comprises a drop door 171 arranged at the entrance opening 42 of the second chamber 40. In these cases, the fish trap comprises a manoeuvring device 180 which is arranged to keep the drop door 171 up when the closing device is in the open position so that the entrance opening 42 of the second chamber thereby is kept open, and which is arranged to release the drop door 171 when being influenced by an activation device 90 of the above- described type, so that the drop door thereby is allowed to drop down over the entrance opening 42 of the second chamber in order to close this entrance opening.

In the embodiments illustrated in Figs 4-7, the drop door 171 is through a line or wire 172 connected to a fastening element 173, for instance in the form of a loop or ring, which fastening element in the open position of the closing device engages with a holding member 185 in the form of a pin or the like of the manoeuvring device 180 in order to keep the drop door 171 up. Said holding member 185 is movable in relation to an attachment 181 included in the manoeuvring device and is under the action of an activation member 91 of the above-described type manoeuvrable from an advanced position in engagement with said fastening element 173 (see Figs 4 and 6) to a retracted position in order to be released from the fastening element 173. When the fastening element 173 is released from the holding member 185 in connection with the displacement of the holding member 185 from the advanced position to the retracted posi- tion, the drop door 171 will be free to drop down under the action of gravity so as to cover the entrance opening 42 of the second chamber. In the examples here illustrated, the holding member 185 is attached to a release member 182 in the form of a lever, which in its turn is hingedly attached to said attachment 181 and connected to said activation member 91. In order to make sure that the fastening element 173 will slide free from the holding member 185 when the holding member is displaced from the advanced position to the retracted position, an abutment (not shown) fixedly connected to the attachment 181 may be ar- ranged between the lever 182 and the fastening element 173 when the fastening element is in engagement with the holding member 185. Also in these cases, the activation member 91 is constituted by an elongated traction transmitting element in the form of a line or wire, which displaceably extends through a tube-shaped jacket 94 and which at one of its ends is attached to the release member 182 of the manoeuvring device 180 and at it other end is attached to a frame-shaped element or a blocking member of a blocking device of the above-described type arranged at the exit opening of the second chamber. In the examples illustrated in Figs 4-7, the manoeuvring device 180 is attached to one of the above-mentioned rings 50 through the attachment 181 .

In the embodiments illustrated in Figs 4-7, the closing device 170 comprises a rigid frame-shaped element 174, for instance of metal, which is attached to the narrower end of a cornet-shaped net section 51 of the above-described type. The frame-shaped element 174 has a central opening forming the entrance opening 42 of the second chamber. In the embodiment illustrated in Figs 4 and 5, the drop door 171 is through a pivotal joint 177 hingedly attached to the upper edge of this frame-shaped element 174 and turnable in relation to this from open position to closed position. In the embodiment illustrated in Figs 6 and 7, the drop door 171 is slidably received in guide members, for instance in the form of guide tracks, in the frame-shaped element 174 and is displaceable in relation to this frame-shaped element from open position to close position guided by said guiding members.

The drop door 171 may for instance comprise a frame-shaped element 175 and a grating 176 attached to this element, as illustrated in Figs 5 and 7.

With the exception of the closing device 170 and the manoeuvring device 180, the fish traps according to Figs 4-7 have the same design as the fish trap described with reference to Figs 1- 3.

An alarm device (not shown) may with advantage be arranged in connection with the manoeuvring device 80, 180 in order to emit an alarm signal to the person who is looking after the fish trap, for instance in the form of an SMS message through a mobile telephone network, when the manoeuvring device 80, 180 is activated and achieves a closing of the entrance opening 42 of the second chamber 40.

The fish trap according to the invention has here been described with respect to the catching of seals. It is however evident that the fish trap according to the invention also could be dimensioned for catching other types of fish-eating predatory animals, such as for instance otters. The invention is of course not in any way limited to the embodiments described above. On the contrary, several possibilities to modifications thereof should be apparent to a person skilled in the art without thereby deviating from the basic idea of the invention as defined in the appended claims.

Claims

1. A fish trap comprising:

- a chamber (10) formed with walls of net, here denominated first chamber, in which fishes swimming into the fish trap (1 ) are intended to be confined, this first chamber (10) having an entrance opening (12) designed to allow passage of fishes into this chamber;

- a chamber (40) formed with walls of net, here denominated second chamber, through which fishes swimming into the fish trap (1 ) are intended to pass on their way to said first chamber (10), this second chamber (40) having an entrance opening (42) designed to allow passage of fishes and seals into this chamber and an exit opening (43) connected to the entrance opening (12) of said first chamber (10); and

- a blocking device (60) arranged at the exit opening (43) of said second chamber (40), which blocking device is arranged to block the exit opening in such a manner that seals are prevented from passing but fishes are allowed to pass through this exit opening in the direction towards said first chamber (10), characterized in that the fish trap (1 ) further comprises:

- a closing device (70; 170) which is manoeuvrable from an open position, in which the closing device keeps the entrance opening (42) of said second chamber (40) open and allows passage of fishes and seals through this entrance opening, to a closed position, in which the closing device keeps this entrance opening (42) closed and thereby prevents seals from passing through this entrance opening out of the second chamber (40);

- a manoeuvring device (80; 180) connected to the closing de- vice (70; 170), by means of which manoeuvring device the closing device (70; 170) is manoeuvrable from its open position to its closed position; and

- an activation device (90) connected to the manoeuvring device (80; 180), which activation device is arranged, by the influence from a seal in the second chamber (40), to activate the manoeuvring device (80; 180) to manoeuvre the closing device (70; 170) from its open position to its closed position so as to thereby achieve confinement of the seal in the second chamber.

2. A fish trap according to claim 1 , characterized in that the ac- tivation device (90) comprises an activation member (91 ) which is connected to the blocking device (60) and which is arranged to be influenced when a seal trying to pass through the exit opening (43) of the second chamber bumps into the blocking device, the activation member (91 ) being arranged to activate the manoeuvring device (80; 180) to manoeuvre the closing device (70; 170) from its open position to its closed position in connection with such an influence.

3. A fish trap according to claim 2, characterized in: - that the activation device (90) comprises a holder (92), to which the blocking device (60) is hingedly attached;

- that the activation device (90) further comprises a tube-shaped jacket (94), preferably in the form of a flexible hose, which at one of its ends is attached to said holder (92) and at its other end is attached to an attachment (81 ; 181 ) that is fixedly connected to the manoeuvring device (80; 180);

- that the manoeuvring device (80; 180) comprises a release member (82; 182) which is movably arranged in relation to said attachment (81 ; 181 ) and which under the action of the activa- tion member (91 ) is manoeuvrable from a rest position to a release position for activation of the manoeuvring device;

- that the activation member (91 ) consists of an elongated traction transmitting element, preferably in the form of a line or wire, which extends through said tube-shaped jacket (94) and which at one of its ends is attached to said release member (82; 182) and at its other end is attached to the blocking device (60), the activation member (91 ) being arranged to be displaced in relation to the tube-shaped jacket (94) and thereby exert a traction on the release member (82; 182) when the blocking device (60) is turned in relation to said holder (92) under the influence of a seal bumping into the blocking device when trying to pass through the exit opening (43) of the second chamber.

4. A fish trap according to claim 3, characterized in that said holder (92) is formed as a frame about the exit opening (43) of the second chamber.

5. A fish trap according to any of claims 1-4, characterized in that the blocking device (60) comprises: - a frame-shaped element (61 ), which has a central opening (62) coinciding with the exit opening (43) of the second chamber, and - at least one elongated blocking member (63), preferably in the form of a line or wire, which is fastened to said frame-shaped element (61 ) and extends across the central opening (62) of this element while dividing this opening into two or more smaller opening areas (62a, 62b).

6. A fish trap according to claim 5 in combination with claim 4 or 3, characterized in that the frame-shaped element (61 ) of the blocking device is hingedly attached to said holder (92) so as to allow the frame-shaped element (61 ) to turn in relation to the holder (92) when a seal trying to pass through the exit opening (43) of the second chamber bumps into the blocking member (63) of the blocking device.

7. A fish trap according to any of claims 1 -6, characterized in that the closing device (70) comprises two rigid and elongated closing elements (71 , 72) arranged opposite each other on opposite sides of the entrance opening (42) of said second cham- ber (40), these closing elements (71 , 72) being displaceable towards each other under the action of a traction from the manoeuvring device (80) in order to close this entrance opening (42).

8. A fish trap according to claim 7, characterized in that the closing elements (71 , 72), in the open position of the closing device, are kept at a distance from each other under the action of two or more elastic members (73).

9. A fish trap according to claim 7 or 8, characterized in that the closing device (70) comprises:

- two tube-shaped jackets (75), preferably in the form of flexible hoses, which at one of their ends are attached to a respective end of a first one (71 ) of said closing elements and at their other end are attached to an attachment (81 ) fixedly connected to the manoeuvring device (80);

- two elongated traction transmitting elements (76), preferably in the form of lines or wires, which extend through a respective one of the tube-shaped jackets (75) of the closing device and which at one of their ends are attached to a respective end of the second closing element (72) and at their other end are attached to a drawing member (84) of the manoeuvring device (80).

10. A fish trap according to any of claims 1-9, characterized in that the manoeuvring device (80) is a gas spring.

1 1. A fish trap according to any of claims 1-6, characterized in:

- that the closing device (170) comprises a drop door (171 ) arranged at the entrance opening (42) of the second chamber (40);

- that the manoeuvring device (180) is arranged to keep the drop door (171 ) up in the open position of the closing device so as to thereby keep the entrance opening (42) of the second chamber open; and - that the manoeuvring device (180) is arranged to release the drop door (171 ) when being influenced by the activation device (90) so that the drop door thereby is allowed to fall down over the entrance opening (42) of the second chamber in order to close this entrance opening.