DK180443B1

DK180443B1 - Gillnet

Info

Publication number: DK180443B1
Application number: DKPA201900986A
Authority: DK
Inventors: Schmidt Sørensen Iver
Original assignee: Iver Schmidt Soerensen
Priority date: 2018-09-17
Filing date: 2019-08-21
Publication date: 2021-04-23
Also published as: DK201900986A1

Abstract

The invention provides a gillnet of the type in use having a fishing net comprising one or more panels of a matrixes of meshes extended between a number of weights and floats and where the gillnet has a plurality of reflective members arranged with predetermined intervals. By using said reflective member as a lure, the fish will be attracted to the reflective members and swim toward said gillnet. When the fish swims into the gillnet, the fish will get caught in the mesh.

Description

DK 180443 B1 1 > |Gillnet} Field of the Invention The present invention relates to a gillnet for fishing.

Background of the Invention : Gillnetting is a common fishing method.

Gillnets are vertical panels of netting normal- ly set in straight lines.

The fish swims into a mesh of the net and passes only partly through the mesh.

When the fish struggles to free itself, the twine, from which the gillnet is manufactured, slips behind the gill cover and prevents escape.

In commercial fisheries the meshes of the gillnets are uniform of size and shape.

Fish smaller than the mesh in the net passes through and fish too large to push their head through the mesh may swim away, as their gills are not retained.

This gives gillnets the ability to target a specific size of fish unlike other net gears such as trawls.

The gillnets are closely monitored.

The mesh size, twine strength as well as the net length and depth are closely regulated to reduce bycatch of non-target species.

The bycatch may be unwanted fish, sharks, seabirds, marine turtles and cetaceans such as whales, dolphins, porpoises.

Globally a huge amount of bycatch is either wasted or left to die.

The drifting gillnet has a low fuel/fish energy consumption compared to other fishing gear.

However, the issue of concern with this type of net is the bycatch of species that are not targeted, may be tangled or caught in the net.

The gillnets are very hard to see, blending in perfectly with the water and the gillnet are difficult for cetaceans to detect by echolocation.

Gillnets that are lost at sea are rarely recovered and may continue to | capture marine animals for many years. | Object of the Invention The object of the invention is to provide an improved gillnet and a method for fishing which reduce the fuel/fish energy consumption and at the same time reduce bycatch, such as marine mammals.

Furthermore to provide a gillnet easy to locate, when being lost.

DK 180443 B1 2 : Description of the Invention The invention provides a gillnet comprising a fishing net extending between a head rope provided with a number of floats, and a foot rope provided with a numbers of weights, and where a plurality of reflective members in the fishing net are provided at predetermined intervals. Gillnets is used in many ways, for example the gilinet may be arranged so the gilinet rests on the bottom, also called a bottom set gilinet. Alternatively the gillnet may be suspended between the bottom and the surface, or float on the surface as a drifting gillnet. Gillnets may be set in one place with anchors or allowed to drift with the cur- rent.

There are for example three methods of catching fish with a gillnet. A first method is “wedged”, where the fish is held by the mesh around the body. A second method is + “gilled”, where the fish is held by mesh slipping behind the opercula. A third method co is “tangled”, where the fish is held by teeth, spines, maxillaries, or other protrusions without the body penetrating the mesh. The present invention applies for all three methods.

By placing the gillnet somewhere between the sea level and the sea bed, depending on i the target fish species to be caught, the fishing may be performed. For example on : small boats, the gillnet may be handled by hand. Larger boats may use hydraulic net haulers or net drums. Gillnets are widely used all over the world and are employed - both in inland and sea waters.

The gillnets are popular with fisheries because no specialized gear is needed. Even though the fishing method is known to be low cost based on the relationship between fuel/fish, the gillnet may be improved by attracting the fish, luring the fish to the gill- net. This causes a significantly increased catch of fish caught by the gillnet. - | Under normal circumstances, the gillnet is invisible for the fish, and the fish are caught because they accidently swim into the gillnet. In this invention the gillnet is improved by providing a plurality of reflective members. This lures the fish to the gillnet, and a larger number of fish will be caught. The reflective members may be

DK 180443 B1 3 : compared to lures. By providing reflective members in predetermined intervals on the gillnet, the fish will be attracted/lured to the reflective members, and be led to swim towards the gilinet. The gillnet is often referred to as “the wall of death”, because the fish may not see the — gillnet. By providing the gillnet with reflective members the gillnet will also be visible to all fish and for marine mammals. The marine mammals will take more caution, when swimming towards the gillnet, because marine mammals may now see a wall of — ' reflective materials and avoid getting tangled into the gillnet.

In an advantageous embodiment of the invention, the reflective members are strips of flexible material comprising one or more materials selected among polymers, metal and/or composite. ) : The reflective members may be produced from different types of material and combi- nations thereof, such as: polymers, metal and/or composite. The reflective members may be flexible, so the reflective members may be tied as a ribbon to the gillnet. The reflective members may also be of a rigid material, where the shape of the reflective member may be the same when being attached to the gilinet and being in use. Fur- - thermore, the reflective members may be similar to lures or flies or other kind of baits + used for fishing. The reflective members may be long and thin, and easily moved by . the current and waving in the seawater. In a further advantageous embodiment of the invention, the reflective members are . strips of flexible material provided with at least one colour. The colour or colours of the reflective members depends on the depths of the gillnet setting, and the fish species to be caught. The colour or colours may be chosen from a - wide variety of ambient parameters for example fishing depth and fish species, and colour parameters, such as hue, saturation and value, or even combined with a grey scale. For example, the colour preferences may change from day to day, based on the variety of food sources, sea and light conditions etc. Green and yellow, black and pur- ple, pearl with red-head, blue and white, and black and gold are some examples of colour combinations which may be used when luring the fish to the gillnet. |

DK 180443 B1 4 In a further advantageous embodiment of the invention, the reflective member is formed as bait.

Fish species as flatfish, such as brill, dab, flounder and plaice are seeking food near the seabed.

By using wormlike bait the flatfish may be lured to the gillnet, and thereby getting caught.

The bait is preferably evenly distributed on the bottom part of the bot- tom set gillnet.

In a still further advantageous embodiment of the invention, the reflective member is provided with an attachment device for attaching the reflective member to the fishing net.

The reflective members may be attached to the fishing net in the process of producing 5 the gillnet, where part of the reflective member is merged into the mesh knot of the ; gillnet, leaving another part of the reflective member free of the gillnet to hang or float in the seawater.

The reflective members may also be attached to the gillnet at a later. stage.

Part of the : reflective members may be clipped, glued, welded and/or tied to the gillnet, and where i another part of the reflective member is free of the gillnet to float in the seawater.

The reflective members may easily be attached to a new or used gillnet, and may easily be removed from the gilinet, and thereafter be reusable.

In a further advantageous embodiment of the invention, the reflective member is bent - around a longitudinal axis of the reflective member.

The reflective member may have a form which is bent or twisted around a longitudinal axis of the reflective member.

The reflective member may therefore have a flattering reflection, constantly moving due to the current in the seawater.

The reflective mem- ber may easily be spotted. - i . Bycatch occurs because the nets also may trap everything larger than the net's mesh.

Bycatch may be marine mammals, which includes juvenile fish, sharks, seabirds, ma-

DK 180443 B1 rine turtles and cetaceans such as whales, dolphins, porpoises. The nets are very hard to see, blending in perfectly with the water and difficult for cetaceans to detect by echolocation. The term echolocation refers to an ability that some cetaceans possess, that enables them to locate and discriminate objects by projecting sound waves and 5 listening for echoes as the sound waves reflect off objects. When using the reflective members provided on a gillnet, the cetaceans are able to detect the reflective members by echolocation. The cetaceans will be aware of a wall : of objects that do not move. By directing the wave, sent from the cetaceans, back to the cetaceans with maximum power, the cetaceans cannot help noticing that the ob- jects are present. This will keep the cetaceans from accidently swimming into the gill- net. The cetaceans will properly be curious and investigate the gillnet with the reflec- tive members, but with caution. This will prevent the cetaceans getting caught in the gillnet. The reflective members may be long or thin objects, and the reflective mem- : bers may be bent or twisted into a form reflecting the sound wave back to the ceta- Gillnets that are lost at sea are rarely recovered and can continue to capture marine ; animals for many years. The reason is among others that the gillnets are hard to find.

To improve the ability to find the lost gillnets, the reflective members may be of great : help. The reflective members are easy to identify. When using for example visual or nonvisual light, sonar or echolocation, the waves of the light, sonar or echo will be reflected. Therefore a search for a lost gillnet provided with reflective members will be easily spotted and identified by the searcher.

In an advantageous embodiment of the invention, the reflective members are provided at predetermined intervals in a target area of the fishing net, where said target area covers the length of the fishing net.

| 30 To lead the fish into the gillnet, the reflective members are distributed strategically throughout the gillnet. The fish will target the reflective members, seeking for food. By providing a distribution of the reflective members in a target area, the fish trying to swim around, but near the reflective members, will still get caught by the gillnet.

| DK 180443 B1 6 : In a further advantageous embodiment of the invention, the reflective members are provided at predetermined intervals in a target area of the fishing net, where the target area covers the length of the fishing net, and the target area is arranged in a predeter- mined height starting at the bottom of the fishing net.

If the gillnet is set as a bottom set gillnet, the reflective members may be distributed on the lower part of the gillnet and preventing most of the fish to swim over the gillnet by luring the fish into the lower part of the fishing net. If the gillnet is set as a drifting gillnet just under the sea level, the reflective members may with advantage be distrib- uted on the top part of the gillnet, preventing most of the fish to swim under the net, ; by luring the fish upwards. If the gillnet is set somewhere between the sea level and the sea bed, it may be with advantage to distribute most of the reflective members near the mid of the gillnet, luring the majority of the fish to the target area of the gillnet.

In a still further advantageous embodiment of the invention, the target area is provided with at least one reflective member per square meter.

The reflective members may be distributed on the gillnet, where at least one reflective . member is provided per square meter. When choosing how many reflective members - must be provided on the gillnet, the target fish species, the mesh size, the dimension of . the gillnet and size and/or weight of the reflective member may be taken into consid- eration. Even other ambient parameters must be taken into consideration as well, for example to reduce or to prevent bycatch. Bycatch mortalities can often be reduced by modifying the fishing gear, so that fewer non-target species are caught.

: The reflective members may be evenly distributed on the fishing net. To catch a large amount of fish, the fish may be spread over the entire area of the gillnet. This may prevent the fish piling op in one area. By spreading the school of fish, a larger amount of fish may get caught, because a large amount of mesh is provided at the gillnet.

: : : The invention further relates to a method of luring fish to a gillnet, wherein said gill- net is provided with at least one reflective member, and using said reflective member | as a lure, attracting the fish with the reflective member, and the fish swimming to- ward said gillnet and into the gillnet and getting caught. :

DK 180443 B1 7 A gilinet catches the fish when the fish swims into the gilinet, and trying to get through and/or free of the gillnet. The netting is suspended straight up-and-down in the water. A gillnet catches fish for example by their gills. The fish may be lured to the gillnet by the reflective members as used as lure and/or bait. The twine of the net- ting is very thin, so therefore the fish do not see the fishing net. The meshes of the fishing net hang wide open. When the fish swims up to the gillnet lured by the reflec- tive members, the fish accidently sticks the head into one of the meshes. If the fish is too small for the mesh, the fish will swim through the mesh and get away. If the fish is too big for the mesh, the fish cannot get the head through the mesh, and the fish will not get caught by the gills. If the fish has the right size, the fish pushes the head and part of the body into the mesh, but the fish cannot get through. When the fish tries to pull the head out of the mesh, the gills and fins are caught in the mesh.

The present invention may also be used in other similar type of nets for fishing by —- luring the fish in a predetermined direction using the reflective members as lures and/or baits. The fish may be directed to an opening or into a maze-like setup, or oth- erwise guided in the direction of the gillnet, where the fish is getting caught. Description of the Drawing : : The embodiments of the invention are described in the following with reference to: Fig. 1: Illustration of a bottom set gilinet provided with reflective members. Fig. 2: Nlustration of a gillnet provided with reflective members with in a target area. Fig. 3: Mlustration of a drifting gillnet provided with reflective members. Detailed Description of the Invention Gillnet fishing uses a wall or curtain of netting, where the netting is suspended in the water. The gillnet may comprise one or more gillnet sections, which are arranged in a line or arranged as a maze structure. Fig. 1 illustrates a bottom set gillnet 1 provided with reflective members. The bottom set gillnet 1 is a fishing net comprising a matrix of meshes 2 with a weighted foot rope 5 along the bottom of the bottom set gillnet 1, arranged near the sea bed 11. The weighted foot rope 5 is held down by sinkers 6, arranged in arbitrary distance to each

DK 180443 B1 3 | other. A head rope 3 is arranged at the top of the bottom set gillnet 1, where floats 4 are evenly distributed along the head rope 3. By altering the ratio of floats 4 to sinkers 6, the bottom set gillnet 1 can be set to fish at any depth in the water column, between the sea level 10 and the sea bed 11. The meshes 2 of the bottom set gillnet 1 may be uniform in size and shape, aimed at the fish species to be caught. The floats 4 usually shaped like eggs or cylinders are often made of for example solid plastic or other material with similar ability to flow. The floats 4 are evenly distributed along the head rope 3, while the sinkers 6 are evenly distributed along the foot rope 5. The foot rope 5 may also be made of lead cored rope, which does not need additional ; sinkers 6. The bottom set gillnet 1 may be set on the sea bed 11, or at a distance above the sea bed 11. The bottom set gillnet 1 is held in place with anchors 7 or weights on both ends of the bottom set gillnet 1. The foot rope 5 and the head rope 3 may be at- tached to the anchors 7, keeping the bottom set gillnet 1 in position near the sea bed 11, when the bottom set gillnet 1 is in use. In each end of the bottom set gillnet 1, a | marker buoy 8 is attached to the anchor 7 through a marker buoy rope 9, showing the outer position of the bottom set gillnet 1, and where the bottom set gillnet 1 is located. Reflective members 13 are approximately equally distributed on the bottom set gillnet 1, luring the fish to the bottom set gillnet 1. : Fig. 2 illustrates a bottom set gillnet 1 provided with reflective members 13 within a target area 12. Reflective members 13 are equally distributed in the target area 12. The target area 12 is chosen to be arranged in the bottom of the bottom set gillnet 1, be- cause the fish may swim over the bottom set gillnet 1. The fish cannot swim under due to the arrangement of the bottom set gillnet 1 so close to the seabed 11. This leaves an area over the target area 12, where there are no reflective members 13. The bottom set gillnet 1 arranged at the sea bed 11 is leaving a “dead end” in two dimensions, one dimension due to the bottom set gillnet 1 and the other dimension due to the sea bed

11. The reflective members 13 arc luring the fish to the bottom of the bottom set gill- net 1 to be caught, because the fish are attracted to the reflective members 13. Fig 3 illustrates a drifting gillnet 15 provided with reflective members 13 in a target area 12. Drifting gillnets 15 are usually used to catch for example schooling forage fish such as herring and sardines, and also larger pelagic fish such as tuna, salmon and

| DK 180443 B1 9 pelagic squid. The drifting gillnet 15 may be set and hauled using a drifter capstan on the forepart of the vessel. The drifting gillnet 15 may be hauled by hand. Some drift- ing gillnet 15 may drift with the current, while other drifting gillnet 15 are attached to . — an operating vessel, the drift netter or drifter.

A drifting gillnet 15 may consist of one or more panels of a matrix of meshes 2 fas- tened together. The drifting gillnet 15 is left free to drift with the current, usually near the sea level 10 or in a predetermined distance below the sea level 10: Floats 4 are attached to the head rope 3 by ropes. Weighted sinkers 6 are attached to the foot rope 5, keeping the drifting gillnet 15 vertical. A marker buoy 8 is attached to each end of the gillnet 15 by using a marker buoy rope 9, showing the outer position of the drifting gillnet 15 and also showing where the drifting gillnet 15 is located. Reflective mem- bers 13 are distributed in predetermined distance from each other on the gillnet 15 ; luring the fish to the gillnet 15.

Reflective members 13 are equally distributed in the target area 12. The target area 12 is chosen to be in the middle of the drifting gillnet 15, because the fish may swim over and swim under the drifting gillnet 15. This leaves an area over and an area under the target area 12 where there are no reflective members 13. Thus, the reflective members 13 are luring the fish to the middle of the gillnet 15 to be caught, because the fish are attracted to the reflective members 13. If the drifting gillnet was placed just below with a very small distance to the sea level 10, the target area 12 would have been chosen differently, and the fish would not be able to swim above the drifting gillnet 15, and the target area 12 would have been ar- ranged to be in the top of the drifting gillnet 15, leaving a "dead end” in two dimen- sions, one dimension due to the drifting gillnet 15, and the other dimension due to the sea level 10.

Claims

DK 180443 B1 10 PATENTKRAV

A gill net comprising a fishing net extending between a main rope with a number of floating elements and a bottom rope provided with a number of weights, and wherein a plurality of reflection elements are provided in the fishing net at predetermined intervals.

The gill net according to claim 1, wherein the reflection elements are strips of flexible material comprising one or more materials selected from polymers, metal and / or composite.

The gill net according to claim 1 or 2, wherein the reflection elements are strips of flexible material formed with at least one color.

The gill net according to claims 1-3, wherein said reflection elements are designed as bait.

The gill net according to any one of the preceding claims, wherein the reflection elements are formed with a fastening device for fastening the reflection elements to the fishing net.

The gill net according to any one of the preceding claims, wherein said reflection elements are bent about a longitudinal axis of the reflection element.

A gill net according to any one of the preceding claims, wherein said reflection elements are provided at predetermined intervals in a target area of the fishing net, said target area covering the entire length of the fishing net.

The gill net according to any one of the preceding claims, wherein said reflection elements are provided at predetermined intervals in a target area of the fishing net, the target area covering the entire length of the fishing net and the target area being arranged at a predetermined height starting at the bottom of the fishing net.

The gill net according to any one of the preceding claims, wherein said target area is provided with at least one reflection element per square meter.

DK 180443 B1 11

A method of luring fish to a gillnet, wherein said gillnet is provided with at least one reflection element, and using said reflection elements as a lure that attracts the fish with the reflection element, and the fish swims towards said gillnet and into the gillnet and is caught.