JP7261126B2 - Flappers in surface and middle layer trawl nets - Google Patents

Description

TECHNICAL FIELD The present invention relates to a flapper in a surface- and middle-layer trawl net for preventing escaping (backward) outside the trawl net when surface- and middle-layer fish that have entered the net once reduce the towing speed.

Illustrated in FIG. 5 is a conventional trawl network 200 . A flapper 201 is used in this trawl net 200 . The flapper 201 is also called a "return", and this flapper 201 is a device that prevents the fish 202 that have entered the net from escaping (reversing) outside the trawl net when the towing speed is reduced. . The reason for lowering the towing speed is that the fluid resistance of the trawl net 200 needs to be reduced in order to hoist the trawl net 200 to the deck side of the ship. A trawl net of this type is disclosed in US Pat.

In the conventional trawling net 210 shown in FIGS. 6A to 6C, only the net panel 211, which is a flapper, is used. is provided with a space 212 for passing fish. A conventional trawling seine 220 shown in FIG. 7 uses a funnel-shaped flapper 221 made of net fabric.

In any of the above fishing methods, the trawling speed is 3 knots or less (1 knot = 0.515 m/s). Therefore, even if the hauling speed is reduced in order to hoist the trawl net with the above specifications, once the fishes enter the net, they do not escape or move backward, and the operation is not hindered. The reason for this is that the swimming speed of fish to be caught is slow.

Japanese Patent Application Laid-Open No. 2007-244384

On the other hand, surface and middle layer trawl nets are intended to catch surface and middle layer fish (mackerel, horse mackerel, etc.) with high swimming speed, and the trawling speed is as high as 4 to 6 knots compared to the above-described conventional operation examples. At that time, as shown in FIG. 8(A), only a mesh panel 211, which is a conventional flapper with a simple structure, is used, or as shown in FIG. 8(C), a funnel-shaped flapper 221 is used. Then, when the trawling speed is reduced for hoisting the net, the surface and middle stratiform fish 240 once entered the net escape from the trawl nets 210 and 220 because the swimming speed of the surface and middle stratiform fish 240 is high. It was gone.

In particular, if only the mesh panel 211, which is a conventional flapper with a simple structure, is used, as shown in FIG. Even if the towing speed is slowed down, the amount of the blown mesh panel 211 is not immediately reduced. A sufficiently large space (passageway) 212D is created in the mesh panel 211 for the surface-medium stratum fish that have entered the net to escape. In addition, the fact that a space for escape is created is similar to the case where the funnel-shaped flapper 221 shown in FIG. 8C is used. Passage) will be created.

Surface- and middle-layer trawl nets are also used in resource surveys of surface- and middle-layer fish (pelagic fish, sardines, horse mackerel, mackerel, tuna, etc.) in Japan. As described above, in surface- and middle-layer trawl nets, a sufficiently large space (passage) is created for the escape of surface- and middle-layer fish that have once entered the net. In this way, if a space is formed in the trawl net where surface- and middle-layer fish can escape, and the above-mentioned escape of surface- and middle-layer fish occurs, accurate fishing (sampling) cannot be performed. Otherwise, it will lead to wrong results (small resource, underestimated).

On the other hand, the space in which fish can escape is not improved even with conventional trawling nets and trawling nets, but the swimming speed of fish to be caught by conventional trawling nets and trawling nets is slow. For this reason, even if the hauling speed is slowed down in order to hoist the net and the amount of blowing of the net panel 211 shown in FIG. You can complete the haul before the fish escape. Therefore, it was not necessary to suppress the escape of fish (to eliminate the space). In other words, since all trawl nets are hoisted before escaping, slow-swimming fish do not have time to escape. This meaning is the same when using the funnel-shaped flapper 221 shown in FIG. 8(C).

Therefore, the present invention has been made to solve the above problems. To provide a flapper in a surface and middle layer trawl net that can prevent escape (reverse exit) to the inside.

The flapper in the surface and middle layer trawl net according to the first aspect of the present invention for achieving the above object is a flapper that is provided in the mesh body of the surface and middle layer trawl net and restricts the escape of fish that have entered the net body. and a net body arranged to close the inside of the net body and opening and closing a passage space for allowing the fish to enter the net inside the net body, wherein the net body is the surface and middle layer trawl net. is provided with a weight that lowers the net body and closes the passage space when the net is towed at a towing speed lower than a predetermined towing speed.

According to the present invention formed in this way, when the weight is being towed at a towing speed lower than a predetermined towing speed, the sinking force of the weight brings the net body into immediate contact with the inside of the net body. to instantly close the passage space. Therefore, it is possible to reliably prevent the fish from escaping by closing the route (space) through which the fish in the surface and middle layers that have already entered the net and whose swimming speed is fast can escape. As a result, it is possible to prevent the fish that have entered the net from escaping (reversing) out of the trawl net when the towing speed is reduced.

The flapper in the surface and middle layer trawl net according to the second aspect of the present invention restricts the passage space from becoming large due to the blowing of the net body when the surface and middle layer trawl net is towed at a predetermined towing speed. It is characterized by having restricting means.

According to the present invention formed in this way, even if the net body of the surface and middle layer trawl net is towed at a high predetermined towing speed when performing the surface and middle layer trawl, the net weight is increased more than necessary due to the seawater flow. The blow amount, which is the amount the body lifts, can be constrained. As a result, the restricting means stabilizes the operation of trawling the surface and middle layer trawl net without making the passage space for the surface and middle layer fish to be caught too large, and stabilizes the normal surface and middle layer trawl for fishing. It is possible to improve the catch rate in the operation of the fishing method.

The flapper in the front and middle layer trawl net according to the third aspect of the present invention has the above-mentioned net body as a first net body and a second net body different from the first net body inside the net body surface. The second net body is arranged in the vicinity of the first net body, and the second net body is used when towing the surface and middle layer trawl net at a towing speed lower than the predetermined towing speed. Further, it has a floating body that moves the second net body to close the passage space.

According to the present invention thus formed, the front and middle layer trawl net includes the second net body separate from the first net body, and the second net body is arranged near the first net body. It is The second net body has a floating body, and the floating body supports the second net body when trawling at a trawling speed lower than a predetermined trawling speed when performing a surface and middle layer trawl using a surface and middle layer trawl net. It has a floating body that moves to close the passage space. As a result, when the towing speed is reduced, the passage space can be doubly closed using the first net body and the second net body, so that the fish entering the net can reduce the towing speed. escaping (reversing) out of the trawl net can be more reliably prevented.

According to the flapper in the surface and middle layer trawl net of the present invention, when the surface and middle layer fish are the target to be caught, the fish entering the net escapes (reverse exit) outside the trawl net when the towing speed is reduced. It is possible to provide a flapper in the surface and middle layer trawl net that can prevent

The perspective view which shows embodiment of the flapper in the surface middle layer trawl net of this invention. A cross-sectional side view showing a stationary unfolded state of a preferred structural example of the surface and middle layer trawl net A cross-sectional side view showing an example of a state in which the surface and middle layer trawl net body is being towed in the towing direction D at a predetermined high towing speed when performing the surface and middle layer trawl. A cross-sectional side view showing that the net body of the front and middle layer trawl net is being towed in the towing direction D at a towing speed slower than a predetermined high towing speed. The perspective view which shows the flapper used for the conventional trawl net (A) is a side sectional view showing a flapper of a conventional trawling net, (B) is a perspective view, and (C) is a front view showing a deformed state of the flapper. (A) is a side sectional view showing another conventional trawling flapper, and (B) is a perspective view. (A) is a side cross-sectional view showing a deformed state of the conventional flapper shown in FIG. 6, (B) is a front view showing the deformed body of the flapper, and (C) is an escape state of the fish from the conventional flapper shown in FIG. side sectional view showing

Preferred embodiments of the invention are described in detail below with reference to the drawings.

The embodiments described below are preferred specific examples of the present invention. The scope of the invention is not limited to this embodiment unless stated to limit the invention.

(embodiment)
FIG. 1 is a perspective view showing an example in which an embodiment of the flapper in the surface and middle layer trawl of the present invention is applied to a fishing boat S. FIG.

In general, in the surface and middle layer trawl fishing method, the left and right front ends of the surface and middle layer trawl net are connected directly or via a net spreader to the left and right warps drawn out from the fishing boat S, and the fishing boat S is moved in the trawling direction at a predetermined high trawling speed. tow the surface and middle layer trawl nets.

In recent years, the surface and middle layer trawl fishing method is used not only for the simple purpose of catching fish, but also for the collection of fish and the like for the purpose of marine resource research. In this fisheries resource survey, it is desired to improve the accuracy of the collected data by performing quantitative collection of fish and the like. For this purpose, it is necessary to keep the opening shape (opening area) of the surface and middle layer trawl net constant. Thus, trawling with the shape of the openings constant is also effective for improving the catch rate in normal surface and middle layer trawl fishing operations for the purpose of catching fish.

(Troll winch 100)
As shown in FIG. 1, a fishing boat S has a deck T on which a trawl winch 100 is installed. The trawl winch 100 has left and right drums 101 and 102 . The left and right drums 101 and 102 of the trawl winch 100 are independently rotationally controlled and driven by hydraulic pressure supplied from, for example, a hydraulic pump as a drive source. The hydraulic pump is rotationally driven by an electric motor or the like.

(Overall configuration of front and middle layer trawl net 1)
FIG. 2 shows a stationary deployed state of a preferred structural example of the surface and middle layer trawl net 1, and FIG. showing. The surface and middle layer trawl net 1 is intended to catch surface and middle layer fish (mackerel, horse mackerel, etc.) having a high swimming speed. The trawling speed of the front and middle layer trawl net 1 by the fishing boat S shown in FIG.

As shown in FIG. 1, the surface and middle layer trawl net 1 includes a net body 2 for entering surface and middle layer fish, which is mounted from a fishing boat S by a pair of left and right warps 3R and 3L and a pair of left and right otter boards 5R and 5L. etc. is towed. The otter boards 5R, 5L secure the opening area of the net body 2 by widening and holding the shape of the opening part 6 of the net body 2 when towing the front and middle layer trawl net 1. - 特許庁This will improve the catch rate in normal surface and middle layer trawl fishing operations aimed at catching fish.

One end sides of the warps 3R and 3L are connected to respective otter boards 5R and 5L. The other ends of warps 3R and 3L are wound around drums 101 and 102 of trawl winch 100, respectively. The trawl winch 100 adjusts the operating conditions of the drums 101 and 102 according to the hauling conditions of the surface and middle layer trawl net 1 according to commands from a control unit (not shown), thereby making the tensions acting on the warps 3R and 3L substantially equal. Hold. As a result, the operation of trawling the surface and middle layer trawl net 1 is stabilized to improve the catch rate in normal surface and middle layer trawl fishing operations for the purpose of catching fish.

(Configuration of Flapper 10)
The flapper 10 is also called a barb and is arranged inside the net body 2 so as to prevent the target fish caught in the net body 2 over the flapper 10 from escaping from the net body 2. , made of mesh material. The flapper 10 has a first net body 11 and a second net body 12, as shown in FIGS. The first net body 11 is arranged on the front side with respect to the trawl direction D of the surface and middle layer trawl net 1, and the second net body 12 is arranged on the rear side with respect to the trawl direction D of the surface and middle layer trawl net 1. , on the rear side of the first net body 11 . The first net body 11 and the second net body 12 each have a lateral width that covers the entire left-right width of the net body 2, and are arranged in a direction that intersects the hauling direction D, for example, in a direction perpendicular thereto. ing.

(First net base 11)
First, the first net base 11 will be described.

The first mesh body 11 shown in FIGS. 1 and 2 is positioned on the upstream side with respect to the hauling direction D, and has a rectangular upper mesh fabric portion 21 and a rectangular lower mesh fabric portion 22, respectively. An upper edge portion 23U and left and right side edge portions 23R and 23L of the upper mesh portion 21 are connected and fixed inside the mesh body 2, respectively. A lower edge portion 24 of the upper mesh cloth portion 21 is formed so as to be a hollow position at a predetermined height from the bottom portion of the mesh body 2 . Only the upper edge portion 25 of the lower mesh portion 22 is connected and fixed to the lower edge portion 24 of the upper mesh portion 21, and the other left and right edges 26R, 26L and the lower edge portion 26D are formed in a free shape. . The size of the lower netting portion 22 is such that the passage space 30, which is an opening formed between the lower edge portion 24 of the upper netting portion 21 and the net body 2, can be fully closed. A weight 27 is fixed to the lower edge portion 26</b>D of the lower netting portion 22 to apply a sinking force to the lower netting portion 22 to fully close the passage space 30 . The weight 27 is preferably made of a metal material that is resistant to corrosion by seawater.

The net 2 shown in FIG. 2 is shown in its unfolded state at rest, not yet pulled in the towing direction D. As shown in FIG. In this stationary state, the lower netting portion 22 is not subjected to the pressure of the sea water generated by the trawling, so that it hangs down vertically from the lower edge portion 24 of the upper netting portion 21 due to the sinking force of the weight of the weight 27 . The passage space 30 for the superficial and mesophytic fishes F to pass is fully closed.

Furthermore, as shown in FIG. 2, between the lower edge portion 24 of the upper netting portion 21 and the bottom surface of the net body 2, there is a restricting rope 31 as restricting means for restricting the blowing amount of the upper netting portion 21. is provided. That is, the restraining rope 31 has a central portion and both side portions. The central portion has a length covering the entire length of the lower edge portion 24 of the upper mesh portion 21 and is fixed to the lower edge portion 24 . Both side portions extending from both ends of the central portion are fixed to the bottom surface of the net body 2 at their ends. As exemplified in FIG. 3, this constraining rope 31 is such that when the net body 2 of the front and middle layer trawl net 1 is towed in the towing direction D at a high towing speed, the mesh portion 21 of the first net body 11 is , serves to restrict the amount of blowing, which is the amount of floating in the Y direction (downstream direction in the hauling direction D) due to the flow of seawater.

As a result, the restricting rope 31 ensures an appropriate opening area of the passage space 30 by preventing the passage space 30 through which the surface-medium-layer fish F to be caught pass from becoming too large. Therefore, it is possible to stabilize the operation of trawling the surface and middle layer trawl net 1 and improve the catch rate in normal surface and middle layer trawl fishing operations for the purpose of catching fish.

FIG. 4 shows that the net body 2 of the front and middle layer trawl net 1 is being towed in the towing direction D at a slow towing speed. The reason for reducing the towing speed in this way is that the net body 2 of the front and middle layer trawl net 1 is to be hoisted (hoisted) onto the deck T side of the fishing vessel S shown in FIG. This is because it is necessary to reduce the fluid resistance of 2.

As illustrated in FIG. 4, the weight 27 shown in FIG. Since the fluid resistance of 2 is reduced, the lower net cloth portion 22 is sunk along the arrow Y1 direction by the sinking force of the weight 27 . Therefore, the lower mesh cloth portion 22 and the weight 27 are kept in immediate contact with the inside of the mesh body 2 . As a result, when the trawling speed becomes slow, the weight 27 immediately closes the passage space 30 to close the route (space) through which surface and middle stratiform fish F1 that have already entered the net can escape. It is possible to reliably prevent a certain superficial and mesophytic fish F1 from escaping from the passage space 30 to the outside.

In this way, the first net body 11 is arranged to open and close the inside of the net body 2, and opens and closes the passage space 30 inside the net body 2 for allowing the superficial and middle layer fishes F to enter the net.

(Second net body 12)
Next, the second net body 12 will be described.

The lower edge portion 41 of the second net body 12 shown in FIGS. 1 and 2 is connected to a position near the passage space 30 on the inner side of the net body 2 and on the downstream side of the first net body 11. there is An upper edge portion 42 of the second net body 12 is provided with a floating body (float) 43 that imparts buoyancy to the second net body 12 . The floating body 43 is made of lightweight plastic such as polyethylene.

As illustrated in FIG. 2, when the net body 2 is not yet pulled in the hauling direction D, the lower net body portion 22 of the first net body 11 brings the weight 27 into contact with the bottom surface of the net body 2. The second net body 12 is held in a state in which the upper edge 42 is lifted by the floating body 43 . Next, as illustrated in FIG. 3, in a state in which the net body 2 is pulled at a high speed in the towing direction D in order to catch fish, the lower net body portion 22 of the first net body 11 on one side is the fast sea. The water flow resists the gravity of the weight 27 and lifts the upper edge portion 25 in the rearward upper direction with the upper edge portion 25 as a fulcrum. With the portion 41 as a fulcrum, it is tilted backward and is almost parallel to the lower mesh portion 22 of the first mesh body 11 . However, when the net body 2 is towed in the towing direction D at a slow towing speed, as shown in FIG. , the passage space 30 can be closed.

Thus, the surface and middle layer trawl net 1 includes the second net body 12 separate from the first net body 11, and the second net body 12 is arranged near the first net body 11. there is The floating body 43 of the second net body 12 has the function of moving the second net body 12 to close the passage space 30 when the surface and middle layer trawl net 1 is towed at a towing speed slower than a predetermined towing speed. have.

(Usage example of surface and middle layer trawl net 1)
Next, an example of use of the front and middle layer trawl network 1 having the above configuration will be described.

The net was cast into the sea from the fishing vessel S shown in FIG. change through. In FIG. 2 , the lower mesh portion 22 of the first mesh body 11 has a weight 27 in contact with the bottom surface of the mesh body 2 to close the passage space 30 , and the second mesh body 12 has a floating body 43 . hold the upper edge 42 in a raised state. In this state, the passage space 30 for passage of superficial and mesophytic fish F is fully closed.

When the fishing boat S tows the net body 2 in the towing direction D at a higher towing speed, the front and middle layer trawl net 1 is positioned in the front and middle layer, and the first net body 11 and the second net body 12 of the flapper 10 are , the state shown in FIG. 2 changes to the state shown in FIG. 3 depending on the flow velocity. That is, one first mesh body 11 is deformed such that the upper mesh part 21 swells rearward, and the lower mesh part 22 moves the upper edge 25 fixed to the lower edge 24 of the upper mesh part 21 . As a fulcrum, the whole is lifted obliquely rearward and upward against the sinking force of the weight 27, and the passage space 30 is gradually opened. The second net body 12 on the other hand is tilted obliquely rearward and downward as a whole against the buoyancy of the floating body 43 with the lower edge 41 fixed to the bottom of the net body 2 as a fulcrum, thereby opening the passage space. 30 will be opened gradually. FIG. 3 shows a state in which the first net body 11 and the second net body 12 are substantially parallel to each other and the passage space 30 is open.

When the passage space 30 is opened in this manner, fish F (mackerel, horse mackerel, etc.) in the surface and middle layers are caught in the inner part of the net body 2 through the passage space 30 .

At this time, as shown in FIG. 3, even if the net body 2 of the surface and middle layer trawl net 1 is towed in the towing direction D at a high towing speed, the constraining ropes 31 are not necessary because of the seawater flow. , constrain the amount of blowing, which is the amount of floating in the Y direction.

As a result, the constraining rope 31 secures an appropriate size of the passage space 30 for allowing the surface and middle layer fishes F to pass through without making the passage space 30 through which the fish F pass too large. Sexual fish F can smoothly enter the net through the passage space 30.例文帳に追加As a result, the surface and middle layer trawl net 1 can accurately catch surface and middle layer fish that swim at a high speed.

Therefore, the flapper 10 of the surface and middle layer trawl net 1 does not hinder entry of surface and middle layer fishes with high swimming speed. By using the flapper 10 in the surface and middle layer trawl net 1 of the embodiment of the present invention, it is possible to collect fish not only for the purpose of catching fish but also for the purpose of surveying marine resources. In this fisheries resource survey, the flapper 10 in the surface and middle layer trawl net 1 can perform quantitative collection of fish and the like to improve the accuracy of collected data.

On the other hand, if the speed of hauling the net body 2 by the fishing boat S shown in FIG. Since the flow of seawater becomes smaller, it is necessary to prevent the surface-medium-layered fish that have already entered the net, especially the surface-medium-layered fish F1 having a high swimming speed, from escaping from the net body 2 through the passage space 30. - 特許庁

When the speed of towing the net body 2 by the fishing boat S slows down, the first net body 11 and the second net body 12 of the flapper 10 shift from the state shown in FIG. 3 to the state shown in FIG. That is, as shown in FIG. 4, the weight 27 and the lower net cloth portion 22 shown in FIG. The side of the edge 26 sinks along the arrow Y1 direction due to the sinking force of the weight 27, thereby keeping the state of being immediately in contact with the inner side of the net body 2. - 特許庁As a result, the weight 27 and the lower net fabric part 22 immediately close the passage space 30 when the trawling speed becomes slow, and close the route (space) through which the surface and middle layer fishes F1 that have already entered the net can escape. By doing so, the escape of the superficial and mesophytic fishes F1 is surely prevented.

Moreover, when the net body 2 is towed in the towing direction D at a slow towing speed, the second net body 12 floats in the direction of the arrow Y2 due to the buoyancy of the floating body 43, thereby closing the passage space 30. can be done. In this way, the passing space 30 can be closed using a double shielding structure with the weight 27, the lower mesh portion 22, the second mesh body 12 and the floating body 43. For this reason, surface- and middle-layer fish that have already entered the net, especially surface- and middle-layer fish F1 with a high swimming speed, do not escape from the net body 2 through the passage space 30 to the outside. Therefore, in a fishery resource survey, the flapper 10 in the surface and middle layer trawl net 1 can perform quantitative collection of surface and middle layer fish and the like, and further improve the accuracy of collected data.

The present invention is not limited to the above embodiments, and various modifications can be made as necessary.

1 Front and middle layer trawl net 2 Net body 3R, 3L Warp 5 Otter board 6 Opening 10 Flapper 21 Upper net part 22 Lower net part 27 Weight (example of weight)
30 passage space 31 restriction rope (example of restriction means)
43 Floating body S Fishing boat T Deck F Surface and middle layer fish F1 Netted surface and middle layer fish

Claims (3)

A flapper provided in a net body of a surface and middle layer trawl net for restricting escape of fish entering the net body,
A net body arranged to close the inside of the net body and opening and closing a passage space inside the net body for allowing the fish to enter the net,
The net body is provided with a weight that lowers the net body and closes the passage space when the surface and middle layer trawl net is towed at a towing speed lower than a predetermined towing speed. Flapper in surface and middle layer trawl. 2. The trawl net according to claim 1, further comprising restricting means for restricting an increase in the passage space due to blowing of the net body when the surface and middle layer trawl net is towed at a predetermined towing speed. Flapper in the surface and middle layer trawl nets. The net body is used as a first net body, and a second net body different from the first net body is provided inside the net body face,
The second net body is arranged near the first net body,
The second net body has a floating body that moves the second net body to close the passage space when the surface and middle layer trawl net is towed at a towing speed lower than the predetermined towing speed. The flapper in the surface and middle layer trawl net according to claim 1 or 2, characterized in that

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