Feeding device and rearing facility for tuna, rearing method for tuna, and tuna

Abstract

This rearing facility comprises: a live-fish enclosure for rearing tuna; and a feeding device within the live-fish enclosure, the feeding device having a cage body configured so as to be capable of holding a plurality of ice blocks that each contain feed. The cage body suppresses the intrusion of tuna and has openings through which feed can pass. The plurality of ice blocks includes at least two ice blocks that differ in size from each other.

Description

Tuna feeding device and rearing facility, tuna rearing method, and tuna

[0001] The present disclosure relates to a tuna feeding device and rearing facility, a tuna rearing method, and tuna.

[0002] When feeding various fish and shellfish such as tuna farmed in fish cages, feeding machines are used. Patent Document 1 proposes a feeding machine including a hopper into which feed such as small fish is introduced, a flow path provided at the bottom of the hopper so as to cross the hopper, and a discharge path that discharges feed toward the fish cage by an air flow from a blower (see, for example, Patent Document 1).

[0003] Non-Patent Document 1 lists methods for feeding tuna: a method of throwing feed fish from a service board into a rearing cage with a shovel, a method of placing frozen block feed fish into a floating cage made of steel mesh in a fish cage, and a method of pumping feed mixed with water to the cage through a tube.

[0004] Utility Model Registration No. 3170780

[0005] ”Atlantic Bluefin Tuna (Thunnus Thynnus) Farming and Fattening in the Mediterranean Sea”, Reviews in Fisheries Science, Volume 18, Issue 3, 2010,p266-280

[0006] One aspect of the present disclosure provides a tuna feeding device and a rearing facility that can efficiently perform tuna farming or fattening. One aspect of the present disclosure provides a tuna rearing method that can efficiently perform tuna farming or fattening. One aspect of the present disclosure provides tuna with sufficiently high commercial value.

[0007] One aspect of the present disclosure provides the following [1] to

[20] .

[0008] [1] A tuna rearing facility comprising a fish farm for raising tuna, and a cage body configured to hold a plurality of ice blocks, each containing bait, within the fish farm, wherein the cage body prevents the entry of the tuna and has openings through which the bait can pass, and the plurality of ice blocks include at least two ice blocks of different sizes. [2] A tuna rearing facility comprising a fish farm for raising tuna, a cage body configured to hold an ice block containing bait within the fish farm, and a frame body supporting the cage body, wherein the cage body prevents the entry of the tuna and has openings through which the bait can pass. [3] A tuna rearing facility comprising a fish farm for raising tuna, and a cage body configured to hold an ice block containing bait within the fish farm, wherein the cage body prevents the entry of the tuna and has openings through which the bait can pass, and the size of the openings in the cage body is uneven. [4] The tuna rearing facility according to any one of [1] to [3], wherein the cage body comprises a side filter surrounding the ice block and a bottom filter through which the bait separated from the ice block passes, and the bottom filter comprises a first opening through which the bait can pass and a second opening smaller than the first opening. [5] The tuna rearing facility according to [4], wherein the side filter comprises a third opening having a size that allows the bait separated from the ice block to pass through the surface layer of the sea, and a fourth opening smaller than the third opening. [6] The tuna rearing facility according to [4] or [5], wherein the opening in the side filter is smaller than the first opening. [7] The tuna rearing facility according to any one of [1] to [6], wherein the cage body comprises a sheet member on the side surrounding the ice block. [8] The tuna rearing facility according to any one of [2] and [4] to [7], wherein the cage body has side filters surrounding the ice blocks and a bottom filter through which the feed separated from the ice blocks passes, and at least the bottom filter is fixed to the frame body so as to be under tension. [9] The tuna rearing facility according to any one of [1] to [8], wherein the feeding device is configured to be movable within the fish farm and is positioned closer to the center of the fish farm than the outer edge when feeding the feed.

[10] The tuna rearing facility according to [1], wherein each of the plurality of ice blocks contains a plurality of feeds including the feed.

[11] The tuna rearing facility according to [2] or [3], wherein the ice blocks include a plurality of baits, including the bait.

[12] A method for rearing tuna, comprising the step of feeding the bait from the feeding device in the rearing facility according to any one of [1] to

[11] .

[13] A method for rearing tuna, comprising the step of feeding the bait to tuna in the pen using a feeding device equipped with a cage body configured to hold a plurality of ice blocks, each containing bait, in the pen, wherein the cage body prevents the entry of tuna and has an opening through which the bait can pass, and the plurality of ice blocks include at least two ice blocks of different sizes.

[14] A method for rearing tuna, comprising the step of feeding the bait to tuna in the pen using a feeding device equipped with a cage body configured to hold ice blocks containing bait in the pen, and a frame body that supports the cage body, wherein the cage body prevents the entry of tuna and has an opening through which the bait can pass.

[15] A method for raising tuna, comprising the step of feeding tuna in a fish farm using a feeding device equipped with a cage body configured to hold a plurality of ice blocks each containing tuna, wherein the cage body prevents the entry of tuna and has an opening through which the tuna can pass, and the size of the opening of the cage body is non-uniform.

[16] A method for raising tuna, wherein the swimming speed of the tuna is 2.0 km / hour or less.

[17] Tuna with a body mass index of 19 or higher.

[18] A feeding device for tuna, comprising a cage body configured to hold a plurality of ice blocks each containing tuna tuna, and a float for floating the cage body in water, wherein the cage body prevents the entry of tuna and has an opening through which the tuna can pass, and the plurality of ice blocks include at least two ice blocks of different sizes.

[19] A tuna feeding device comprising a cage body configured to hold an ice block containing tuna bait, a float for floating the cage body in water, and a frame body for supporting the cage body, wherein the cage body prevents the entry of tuna and has an opening through which the bait can pass.

[20] A tuna feeding device comprising a cage body configured to hold an ice block containing tuna bait, and a float for floating the cage body in water, wherein the cage body has an opening that prevents tuna from entering and through which the bait can pass, and the size of the opening of the cage body is non-uniform.

[0009] The tuna rearing facilities described in [1] to

[11] above all include a feeding device having a cage body that is configured to hold ice blocks containing feed within the cage and has an opening through which the feed can pass. The cage body prevents tuna from entering while having an opening through which the feed can pass, so the feed is supplied to the tuna as it passes through the opening of the cage body. With this method of feeding, the tuna can consume the feed without becoming overly excited, and thus the tuna can grow steadily. Therefore, the above rearing facilities can efficiently carry out tuna farming or aquaculture.

[0010] The tuna rearing methods described in

[12] to

[16] above all utilize a feeding device that has a cage body configured to hold ice blocks containing feed within the pen and has an opening through which the feed can pass. The cage body prevents tuna from entering while having an opening through which the feed can pass, so the feed is supplied to the tuna as it passes through the opening of the cage body. With this method of feeding, the tuna can consume the feed without becoming overly excited, and thus the tuna can grow steadily. Therefore, the above rearing methods enable efficient tuna farming or aquaculture.

[0011] The tuna species mentioned in

[17] above are efficiently farmed or aquacultured and have sufficient commercial value.

[0012] The tuna feeding devices described in

[18] to

[20] above all include a cage body configured to hold ice blocks containing tuna bait. The cage body has openings that prevent tuna from entering while allowing bait to pass through, so that the bait is fed to the tuna as it passes through the openings of the cage body. With this method of feeding, the tuna can consume the bait without becoming overly excited, thus allowing them to grow smoothly. Therefore, the above feeding devices enable efficient tuna farming or aquaculture.

[0013] According to one aspect of this disclosure, it is possible to provide a tuna feeding device and rearing equipment that can efficiently carry out tuna farming or aquaculture. According to one aspect of this disclosure, it is possible to provide a tuna rearing method that can efficiently carry out tuna farming or aquaculture. According to one aspect of this disclosure, it is possible to provide tuna with sufficiently high commercial value.

[0014] This is a side view showing an example of tuna rearing equipment. This is a plan view of the tuna rearing equipment shown in Figure 1. This is a perspective view showing an example of a feeding device. This is a magnified view of an example of a filter in a cage. This is a perspective view showing an example of an ice block. This is a perspective view showing an example of a cage in a feeding device. This is a perspective view showing an example of a cage in a feeding device. This is a perspective view showing an example of an ice block. This is a perspective view showing an example of a feeding device. This is a perspective view showing an example of a feeding device. This is a plan view showing an example of a bottom filter in a cage of a feeding device.

[0015] Embodiments of this disclosure will be described below, with reference to the drawings as appropriate. However, the following embodiments are illustrative for explaining the present invention and are not intended to limit the present invention to the following. In the description, the same reference numerals will be used for elements that are the same or have the same function, and redundant explanations will be omitted as appropriate. Positional relationships such as up, down, left, and right will be based on the positional relationships shown in the drawings unless otherwise specified. The dimensional ratios of each element are not limited to the ratios shown. In these embodiments, numerical ranges indicated by "~" include numerical values ​​indicated as upper and lower limits. Numerical ranges in which the upper and lower limits of a numerical range are replaced with the values ​​of the embodiment are also included in this disclosure. If a numerical range is illustrated with only an upper limit or only a lower limit, a numerical range combining the numerical range with only an upper limit and the numerical range with only a lower limit is also included in this disclosure. Numerical ranges in which the upper and / or lower limits of one numerical range are replaced with the upper and / or lower limits of another numerical range are also included in this disclosure. Multiple examples of substances and materials may be used individually or in combination of two or more arbitrarily selected types. This disclosure also includes applying the concepts described in one embodiment to another embodiment.

[0016] In this disclosure, "tuna rearing facilities" may refer to aquaculture facilities for farming tuna, or to aquaculture facilities for keeping tuna. In this disclosure, "tuna rearing facilities" may also be simply referred to as "rearing facilities." In this disclosure, "tuna rearing methods" may refer to aquaculture methods for farming tuna, or to aquaculture methods for keeping tuna. In this disclosure, "tuna feeding devices" may also be simply referred to as "feeding devices."

[0017] In this disclosure, “Aquaculture facilities” and “Aquaculture methods” may refer to aquaculture facilities and methods for farming tuna, or to aquaculture facilities and methods for raising tuna. In this disclosure, “tuna” refers to a general term for fish belonging to the genus Thunnus in the family Scombridae, order Perciformes. In this disclosure, “feed” may refer to anything that can be used as feed for “tuna.” “Feed” may refer to feed fish, other marine life, moist pellets, or compound feed. Examples of feed fish include horse mackerel, mackerel, saury, herring, skipjack tuna, and sardines. Examples of other marine life include crustaceans and squid. Compound feed may refer to extracted pellets. Since the feed is contained in ice blocks, it may be frozen. In this disclosure, “fish farm” refers to an underwater space or facility for raising fish, formed by partitioning a part of a body of water such as the sea using nets or the like. On the other hand, a "cage body" is a smaller container or basket placed inside a fish farm to temporarily hold ice blocks containing bait.

[0018] The “ice block” in this disclosure may contain at least one type of bait, and may contain multiple types of bait. The multiple types of bait may differ in size and type from one another. The “ice block” may be produced by freezing bait with water or saltwater. Tap water or groundwater may be used as the water. Seawater may be used as the saltwater. Since water has a higher freezing point than saltwater, using water allows for faster production of the ice block using freezing equipment. By using saltwater such as seawater, the freezing temperature can be lowered, thus preserving the freshness of the bait fish.

[0019] The “cage” in this disclosure only needs to be capable of containing one or more ice blocks containing bait and temporarily holding the ice blocks immediately after they are immersed in seawater, but the ice blocks that have melted and become smaller in the seawater may not be held and may flow out. Furthermore, the “cage” must suppress the entry of tuna larger than the bait, while also having an opening through which the bait can pass. Here, a cage that suppresses the entry of tuna is not only composed of an opening that is too small for tuna to physically enter, but may also be one that tuna will not swim into on their own. In other words, even if a cage has an opening that tuna can physically pass through, a cage composed only of an opening that is too small for tuna to avoid due to their behavioral habits also falls under the category of a cage that suppresses the entry of tuna. This effectively suppresses the entry of tuna into the cage.

[0020] The size of the openings in the "cage body" and "filter" may be uniform or non-uniform. It is not necessary for bait to pass through all openings; it may be necessary for bait to pass through only some openings. The "filter" may be, for example, a mesh body, a grating, or a screen. The material constituting the filter may be flexible or rigid, depending on its properties. Flexible materials include, for example, mesh bodies made of synthetic fibers such as nylon, polyethylene, polypropylene, polyvinyl chloride, and polyester. By using flexible materials, the impact when tuna collide with the filter can be mitigated, reducing damage to the fish. On the other hand, rigid materials include, for example, metal gratings and rod-shaped members made of stainless steel or fiber-reinforced plastic (FRP), and resin tubes and slit materials made of polyvinyl chloride resin. By using rigid materials, deformation of the filter due to water flow or the weight of ice chunks can be suppressed, the opening shape can be stably maintained, and the smooth passage of bait can be ensured. These materials may be used differently depending on the part of the filter (for example, the side filter and the bottom filter).

[0021] The net may be capable of holding ice blocks containing bait and may have mesh sizes that allow bait to pass through. Nets with mesh sizes that allow bait to pass through include not only those where the entire net has mesh sizes that allow bait to pass through, but also those where only a part of the net has mesh sizes that allow bait to pass through. The size and shape of the mesh in the net may be uniform or non-uniform.

[0022] <First Embodiment of Feeding Device and Rearing Facility> The rearing facility for tuna according to the first embodiment comprises a fish farm for rearing tuna and a feeding device having a cage body configured to hold a plurality of ice blocks, each containing feed, within the fish farm. The cage body prevents tuna from entering and has an opening through which feed can pass, and the plurality of ice blocks include at least two ice blocks of different sizes. The feeding device may comprise the cage body and a float for keeping the cage body afloat in the water. The cage body of the feeding device may have a filter that prevents tuna from entering and has an opening through which feed can pass. At least a part of the filter constituting the cage body may be a mesh made of synthetic fibers. This reduces damage when tuna collide with the filter. The plurality of ice blocks include at least two ice blocks of different sizes.

[0023] As shown in Figure 1, an example of a rearing facility 100 includes a fish tank 70 for rearing tuna 50 and a feeding device 10 configured to feed the tuna 50 within the fish tank 70. The fish tank 70 is configured to allow the tuna 50 to move around and includes a fish tank body 71 that demarcates the area for rearing the tuna 50, and a float 74 that has buoyancy to keep at least a part of the fish tank body 71 in the sea 90. The float 74 is not particularly limited as long as it floats in the sea 90, and may be made of polystyrene foam, for example. The fish tank body 71 has a net body 72 with a mesh size that the tuna 50 cannot pass through, thereby preventing the tuna 50 from escaping to the outside of the fish tank 70. The mesh size of the net body 72 of the fish pen body 71 may be larger than the opening OP of the filter 80 provided in the cage body 30 of the feeding device 10. The rearing facility 100 may float above the seabed and be fixed to the seabed by ropes 76. The tuna 50 may grow larger by consuming the food 40 that sinks from the feeding device 10. Since the feeding device 10 is held near the surface of the sea, the tuna 50 can smoothly consume the food 40 that sinks from the feeding device 10.

[0024] As shown in Figures 1 and 2, the fish pen body 71 of the breeding facility 100 may have a roughly rectangular prism shape. Here, "roughly rectangular prism shape" does not mean a strictly geometric rectangular prism, but includes shapes that can be substantially recognized as a rectangular prism, such as shapes with curved corners or bulging sides. However, the shape of the fish pen body 71 is not particularly limited and may have a cylindrical shape, or a conical, square pyramidal, or triangular pyramidal shape that tapers towards the seabed. The size of the fish pen body 71 may be, for example, 10 to 100 m in length and width, and 10 to 50 m in depth from the sea surface.

[0025] The feeding device 10 may be placed in the center of the fish pen 70. This allows the tuna 50 to consume the bait 40 smoothly. It also prevents the tuna 50 from colliding with the fish pen body 71 during feeding. Placing the feeding device 10 in the center of the fish pen 70 is not mandatory; for example, it may be placed closer to the center than the outer edge of the fish pen 70. The number of feeding devices 10 is not particularly limited, and multiple feeding devices 10 may be provided in one fish pen 70. A service area 95 is provided outside the fish pen 70. The service area 95 will be described later.

[0026] The feeding device 10 illustrated in Figure 3 comprises a cage 30 configured to hold one or more ice blocks, and a float 20 provided above the cage to keep the cage 30 afloat in the water. The cage 30 has a rectangular prism shape with an open top and has sides 35 and a bottom 36. The sides 35 and bottom 36 may be composed of filters 80 that suppress the entry of tuna 50. The cage 30 has a side filter 80S on the side 35 and a bottom filter 80A on the bottom 36. Both the sides 35 and bottom 36 may be composed of filters 80 that suppress the entry of tuna 50 and allow bait 40 to pass through, or only the bottom 36 (bottom filter 80A) may be composed of a filter that allows bait 40 to pass through.

[0027] The floating body 20 comprises a raft 22 formed by connecting the ends of four sets of first rod-shaped members 22A and second rod-shaped members 22B, each set being arranged parallel to the other, so that the overall structure forms a rectangle, and a float 24 fixed between the first rod-shaped members 22A and second rod-shaped members 22B. The size of the raft 22 may be, for example, 1 to 6 m in length on one side. The first rod-shaped members 22A and second rod-shaped members 22B may be made of resin, wood, or metal. The float 24 is not particularly limited as long as it floats in the sea like the float 74, and may be made of, for example, polystyrene foam. In Figure 3, for illustrative purposes, the floating body 20 and the cage body 30 are shown separated, but the floating body 20 and the cage body 30 may be connected by connecting members such as ropes or jigs.

[0028] Figure 4 shows a magnified view of a portion of the filter 80 (bottom filter 80A, side filter 80S) in the cage body 30. The filter 80 has an opening OP through which the bait 40 can pass, and a partitioning material SE that partitions the opening OP. The partitioning material SE may be netting, rope, or a rod-shaped member. If the filter 80 is a net, the length MS of the diagonal is the mesh size of the net. The opening OP may be large enough that tuna 50 cannot pass through. This prevents tuna 50 from entering the cage body 30. The filter 80 may be a net, grating, or screen. The material of the filter 80 (partitioning material SE) is not particularly limited and examples include resins such as nylon, polyethylene, polypropylene, polyvinyl chloride, and polyester, as well as metals such as stainless steel.

[0029] The cage 30 may hold ice blocks 60 as shown in Figure 5. The ice blocks 60 may be placed in the cage 30 of the feeding device 10 from the service area 95 shown in Figure 2 using heavy machinery such as a crane. At this time, the feeding device 10 may be positioned near the outer edge of the fish farm 70 as shown by the dotted line in Figure 2. After multiple ice blocks 60 have been placed in the cage 30 of the feeding device 10, the feeding device 10 shown in Figure 2 may be moved to the center of the fish farm 70 by pulling a rope (not shown) connected to the raft 22, for example, using the power of a ship (roller) or by human power. The multiple baits 40 contained in the ice blocks 60 may be of different sizes.

[0030] The opening OP of the filter 80 may be sized so that the ice chunks 60 cannot pass through. Therefore, the ice chunks 60 do not need to pass through the filter 80 until they have melted to some extent in the sea. When the ice chunks 60 melt in the sea, the bait 40 contained in the ice chunks 60 separates from the ice chunks 60 and flows out to the outside of the cage body 30 as shown in Figure 1, and sinks toward the bottom of the net body 72. The feeding device 10 can significantly reduce the impact noise hitting the sea surface compared to when the bait 40 is fed from above the sea 90, as with a feeder. Therefore, the tuna 50 can be fed in a quiet environment. Consequently, it is possible to suppress the tuna 50 from colliding with each other due to excitement, or from colliding with the net body 72. In addition, the stress on the tuna 50 is reduced, and they do not need to exercise unnecessarily, allowing the tuna 50 to grow smoothly without consuming unnecessary calories.

[0031] The ice block 60 may contain multiple ice blocks 61, 62, 63, 64, and 65 (hereinafter referred to as "ice blocks 61 to 65"). When such ice blocks 61 to 65 are placed inside the cage 30, they gradually melt upon contact with seawater. The bait 40 contained in the ice blocks 61 to 65 may be separated from the ice blocks 61 to 65, pass through the filter 80 of the cage 30, flow out to the outside of the cage 30, and be consumed by tuna 50.

[0032] The ice blocks 61-65 may be of different sizes. This allows for staggered timing of the supply of bait 40 because the melting rates of the ice blocks 61-65 are different. Therefore, the bait 40 is supplied slowly from the ice blocks 61-65 over time, reducing the amount of bait 40 that falls to the seabed without being consumed. This reduces bait waste and improves feed cost ratio (FCR). In addition, the tuna 50 can calmly consume the bait 40 without becoming agitated. The number of ice blocks contained in ice block 60 is not limited to 5, but may be 2-50, 5-40, 7-30, or 8-20.

[0033] Once feeding is complete, the feeding device 10 may be towed by the boat and moved from the center of the pen 70 to the position shown by the dotted line in Figure 2. After that, the ice blocks 60 may be placed in the cage 30 and feeding of the tuna 50 may be repeated. Moving the feeding device 10 to the center of the pen 70 is not mandatory; feeding of the tuna 50 may be performed with the feeding device 10 positioned near the outer edge of the pen 70. Positioning it near the outer edge limits the direction in which the tuna 50 can enter the feeding device 10, thereby suppressing collisions between fish. Also, having the feeding device 10 near the outer edge allows for smoother placement of the ice blocks 60. The number of feeding devices 10 placed in the pen 70 may be one or two or more.

[0034] The cage 30 of the feeding device 10 contains ice blocks 60. Feeding of tuna 50 can be performed without the need to melt or crush the ice blocks 60 separately. Therefore, by using the rearing equipment 100 and the feeding device 10, the labor and time required for feeding can be significantly reduced.

[0035] <Second Embodiment of Feeding Device and Rearing Facility> The rearing facility for tuna according to the second embodiment comprises a cage for rearing tuna and a feeding device having a cage body configured to hold ice blocks containing feed within the cage. The cage body has multiple openings that prevent the entry of tuna and allow feed to pass through, and the size of these multiple openings is non-uniform. The feeding device for tuna may comprise a cage body configured to hold ice blocks containing tuna feed and a float that makes the cage body float in the water. The cage body has multiple openings that prevent the entry of tuna and allow feed to pass through. The cage body may comprise a filter having multiple openings of non-uniform size.

[0036] The cage 30A illustrated in Figure 6 may be provided in place of the cage 30 of the feeding device 10 shown in Figures 1, 2, and 3. The structure other than the cage 30A may be the same as or different from that of the first embodiment. The cage 30A may have sides 35 provided to surround the ice block 60 and a bottom 36 provided for the passage of the bait 40, similar to the cage 30. The bottom 36 of the cage 30A may be composed of a bottom filter 80C having a first opening OP1 through which the bait 40 can pass and a second opening OP2 smaller than the first opening OP1. By providing the first opening OP1 in the bottom filter 80C, for example, blockage of clumps of bait 40 and stagnation of the bait 40's sinking can be suppressed, and feeding to the tuna 50 can be made even smoother.

[0037] The second opening OP2 may be large enough for the bait 40 to pass through. The opening OP of the side filter 80S in the side 35 may be smaller than the first opening OP1. This allows a sufficient amount of bait 40 to pass through the bottom filter 80C in the cage body 30A, so that the tuna 50 can efficiently consume the bait 40 below the cage body 30A. The side filter 80S and the bottom filter 80C may be, for example, meshes with different mesh sizes. The mesh sizes of the meshes constituting the bottom filter 80C are non-uniform. Here, "non-uniform" includes a state in which openings of different sizes are arranged regularly or irregularly. For example, multiple openings of different sizes may be randomly mixed, or the size of the openings may differ in each predetermined area.

[0038] The feeding device 10 may have a cage body 30B instead of the cage body 30A, as shown in Figure 7. The cage body 30B may have sides 35 surrounding the ice block 60 and a bottom 36 supporting the ice block 60, similar to the cage body 30. The sides 35 are made up of side filters 80B. The bottom 36 may be made up of a bottom filter similar to that in Figure 6. The side filters 80B have a third opening OP3 that is large enough for the food 40 to pass through, and a fourth opening OP4 that is smaller than the third opening OP3.

[0039] For example, if the bait fish contained in the bait 40 are high in fat, they may float to the surface of the seawater without passing through the bottom filter. In this way, the bait 40 floating in the surface layer of the sea can be released to the outside of the cage body 30 through the third opening OP3. Such bait 40 may also be consumed by tuna 50. The third opening OP3 may be located above the center in the vertical direction of the side portion 35. The fourth opening OP4 may be too large for the bait 40 to pass through. The bottom filter at the bottom portion 36 may have an opening OP that is large enough for the bait 40 to pass through. The bait 40 may pass through the bottom filter at the bottom portion 36 and the third opening OP3 of the side filter 80B and be released to the outside of the cage body 30B.

[0040] The cage body of the feeding device 10 in this embodiment is not limited to the cage body 30A in Figure 6 and the cage body 30B in Figure 7. For example, it may be a cage body having a bottom filter 80C in Figure 6 at the bottom and a side filter 80B in Figure 7 at the side. The shape of the cage body is not limited to a rectangular prism shape. The cage body may hold an ice block 60 as shown in Figure 5, or an ice block 60A as shown in Figure 8. Even with an ice block 60A, since the cage body has multiple openings of different sizes, the number of bait 40 descending can be appropriately adjusted. This reduces the amount of bait 40 that falls to the seabed without being consumed. In addition, the tuna 50 can calmly consume the bait 40 without becoming agitated. The ice block 60A or the multiple bait 40 contained in the ice block 60 may be of different sizes.

[0041] <Third Embodiment of Feeding Device and Rearing Facility> The rearing facility for tuna according to the third embodiment comprises a fish pen for rearing tuna, and a feeding device having a cage body configured to hold ice blocks containing bait within the fish pen, and a frame body that supports the cage body. The tuna feeding device may comprise a cage body configured to hold ice blocks containing tuna bait, and a float that makes the cage body float in the water. The cage body prevents tuna from entering and has an opening through which bait can pass. The cage body may have a filter with an opening through which bait can pass.

[0042] The feeding device 10A illustrated in Fig. 9 may be provided in the breeding equipment 100 instead of the feeding device 10 shown in Figs. 1, 2 and 3. Structures other than the feeding device 10A may be the same as those in the first embodiment and the second embodiment, or may be different therefrom. The feeding device 10A may include a cage body 30 configured to be capable of holding one or more ice blocks, and a floating body 20 that floats the cage body 30 from the seabed and holds it near the sea surface. The floating body 20 may have the same structure as the floating body 20 in the feeding device 10 of Fig. 3. The cage body 30 in Fig. 9 may accommodate and hold the ice block 60 of Fig. 5, or may accommodate and hold the ice block 60A of Fig. 8.

[0043] The cage body 30 has a quadrangular prism shape with an open upper surface, and includes a side portion 35 and a bottom portion 36. The side portion 35 and the bottom portion 36 may be formed of a filter 80 that suppresses invasion of tunas 50. The side portion 35 and the bottom portion 36 may be formed of a side filter 80S and a bottom filter 80A that allow the feed 40 to pass through, or only the bottom filter 80A on the bottom portion 36 may allow the feed 40 to pass through.

[0044] The cage body 30 includes a frame body 38. The frame body 38 includes a frame portion 38A provided along the inner corners of the side portion 35 and the bottom portion 36, and pillar portions 38B provided along inner corners of two adjacent side surfaces of the cage body 30. Since the cage body 30 includes the frame body 38, deformation of the filter 80 constituting the cage body 30 can be suppressed. This allows the feed 40 to smoothly pass through the filter 80, enabling stable feeding of tunas 50. The material of the frame body 38 is not particularly limited, and may be made of metal such as stainless steel, or may be made of resin, wood, or ceramics.

[0045] The filter 80 may be a mesh body. The filter 80 may be fixed to the frame body 38 under tension. This sufficiently suppresses bending and deformation of the filter 80 and allows more stable feeding of tuna 50. The shape of the frame body 38 is not limited to the structure shown in Fig. 9. For example, a structure may be adopted in which a frame portion similar to the frame portion 38A is also provided at the upper end of the cage body 30, and the two frame portions are connected by four pillar portions 38B. Alternatively, the pillar portion 38B may not be provided, only the frame portion 38A may be provided, and tension may be applied to the entire filter 80 by the weight of the frame portion 38A or the ice blocks 60 (ice blocks 60A). Further, instead of the frame portion 38A, a frame portion similar to the frame portion 38A may be provided at the upper end of the cage body 30, and a pillar portion 38B extending downward from the frame portion may be provided.

[0046] The shape of the frame body 38 may be changed according to the shape of the cage body 30. For example, when the cage body 30 has a cylindrical outer shape, the frame portion 38A may be annular. In this case, for example, a plurality of pillar portions 38B may be provided connected to the frame portion 38A at equal intervals. At least one of the frame portion 38A and the pillar portion 38B may be formed of a circular pipe.

[0047] The feeding device 10C illustrated in Fig. 10 has a bottom filter 80D at the bottom of the cage body 30C. As shown in Fig. 11, the bottom filter 80D may be composed of a plurality of slit members 86 arranged parallel to each other and gaps 87 provided between adjacent slit members. The plurality of slit members 86 may extend along the sea surface and be fixed to the frame portion 38A of the frame body 38 so as to be parallel to each other. The slit member 86 may be a flat plate-shaped or rod-shaped member, or may be a resin tube such as a vinyl chloride resin tube. The bait 40 may pass through the gaps 87 provided between adjacent slit members 86 and descend toward the seabed. That is, the gap 87 may be one form of the opening. The width W of the gap 87 may be a size that allows the bait 40 to pass through but does not allow the tuna 50 to pass through.

[0048] As shown in Figure 10, a mesh body may be provided as a side filter 80S on the side 35 of the cage body 30C, and a bottom filter 80D may be provided on the bottom 36 without a mesh body, consisting of a slit material 86 and an opening 87. If the bottom filter 80D is made of a slit material 86 that is more rigid than the mesh body that makes up the side filter 80S, the blockage of the bait 40 due to the bending of the bottom can be sufficiently suppressed.

[0049] The arrangement of the multiple slit materials 86 is not particularly limited. For example, the slit materials may be arranged to intersect to form a grid-like bottom filter. Also, the width W of the multiple gaps 87 may not be uniform, but rather uneven.

[0050] <Modifications of Feeding Device and Rearing Equipment> At least a portion of the side portion 35 of the cage body 30, 30A, 30B, 30C in each of the above embodiments may be covered with a sheet member that does not have an opening. The sheet member may be provided so as to cover at least a portion of the side filter 80S, or the sheet member may be provided on the side portion 35 instead of the side filter 80S. This makes it possible to change the amount of seawater passing through the cage body 30 and adjust the melting rate of the ice block 60 (ice block 60A). As a result, the frequency of food 40 falling from the cage body 30 can be changed to make it easier for tuna 50 to feed. The size of the sheet member and the ice block 60 (ice block 60A) may be changed according to the seawater temperature. For example, in the summer when the seawater temperature is high, the area covered by the sheet member may be made larger than in the winter when the seawater temperature is low to reduce the melting rate of the ice block 60 (ice block 60A). Also, in the winter when the seawater temperature is low, smaller ice blocks may be used than in the summer when the seawater temperature is high.

[0051] Birds may gather in the fish farm to target the bait 40. The feeding devices 10, 10A, and 10C of each of the above embodiments may be equipped with a net that covers the top of the cages 30, 30A, 30B, and 30C when the ice block 60 (ice block 60A) is contained within. This can prevent birds from preying on the bait 40 inside the cages 30, 30A, 30B, and 30C. When introducing the ice block 60 (ice block 60A) into the cages 30, 30A, 30B, and 30C, the net can be removed. Also, tuna can be stressed by birds. By using a net to deter birds from approaching, tuna can feed without stress.

[0052] The feeding devices 10, 10A, and 10C may be configured to move within the fish farm 70. For example, the floating body 20 or frame 38 may be provided with connecting parts (hooks, rings, etc.) for attaching ropes or towing jigs. An operator may connect a rope to these connecting parts and tow the feeding device 10 using a winch installed on a boat or on land, thereby moving the feeding devices 10, 10A, and 10C between the outer edge and the center of the fish farm 70. The method of moving the feeding devices 10, 10A, and 10C is not limited to towing. For example, the feeding devices 10, 10A, and 10C may be configured to be self-propelled by being equipped with a propulsion device such as a screw or propeller and a drive source such as a motor. Alternatively, the feeding devices 10, 10A, and 10C may be equipped with a mechanism that moves along a guide wire or the like installed in the fish farm 70.

[0053] The shape of the cages 30, 30A, 30B, and 30C is not limited to a rectangular prism shape; they may also be cylindrical, or, for example, gradually narrowing towards the seabed in a bowl shape. The shape of the ice block is not limited to the shapes shown in Figures 5 and 8. For example, the ice block 60 in Figure 5 is divided into five parts along the horizontal direction, but in a modified example, the ice block may be divided into multiple parts along the vertical direction. The ice block may be divided along both the horizontal and vertical directions, with multiple blocks arranged along the horizontal direction and stacked along the vertical direction.

[0054] The ice blocks 60 and 60A may be prepared, for example, by stacking them on pallets to which ropes are attached. Preparing them on pallets makes transportation and storage in the freezer easier. The pallets loaded with ice blocks 60 and 60A may be lifted by a crane using a net or the like and placed into the cages 30, 30A, 30B, and 30C. The placed pallets may be retrieved by pulling the ropes after feeding. In this configuration, the pallets loaded with ice blocks 60 can be placed into the cage 30 with a crane, resulting in good work efficiency. However, the use of pallets is not mandatory; for example, the ice blocks 60 and 60A may be lifted by a crane using a basket and placed into the cages 30, 30A, 30B, and 30C.

[0055] This disclosure also includes applying the contents of one embodiment to other embodiments. For example, the cage 30 in Figure 3, the cage 30A in Figure 6, or the cage 30B in Figure 7 may be provided with a frame 38 as shown in Figure 9, or with a frame portion 38A and a bottom filter 80D as shown in Figure 11. The bottom 36 of the cage 30 shown in Figure 9 may be provided with the bottom filter 80C of Figure 6. The side portion 35 of the cage 30 shown in Figure 9 may be provided with the side filter 80B of Figure 7.

[0056] <Method for raising tuna> One embodiment of the method for raising tuna includes a step of feeding feed from a feeding device. The feeding device may be any of the feeding devices in the above-described embodiment. This method may be carried out using the rearing equipment 100 in the above embodiment, or it may be carried out using equipment different from the rearing equipment 100. The following explanation will use the case in which the rearing equipment 100 and the feeding device 10 are used as an example.

[0057] In one example of the rearing method, the feeding device 10 is placed inside the fish tank 70. The cage body 30 of the feeding device 10 may be placed near the outer edge of the fish tank 70, floating in the water by a float 20. The ice blocks 60 (ice blocks 60A) placed in the service area 95 may be placed into the cage body 30 of the feeding device 10, which is placed near the outer edge of the fish tank 70, using heavy machinery such as a crane.

[0058] Afterward, the feeding device 10 is moved to the vicinity of the center of the fish farm 70 by pulling the rope connected to the feeding device 10, for example, with the ship's power (roller). The feeding device 10 may be moved by pulling it with a rope by hand, or by being towed by a ship. During the movement, a portion of the ice block 60 (ice block 60A) may melt. After the movement, as the melting of the ice block 60 (ice block 60A) progresses, the bait 40 passes through the filter 80 of the cage body 30 and flows out to the outside of the cage body 30. The bait 40 that flows out to the outside of the cage body 30 slowly sinks toward the seabed. The sinking bait 40 is consumed by tuna 50. After the ice block 60 (ice block 60A) is placed in the cage body 30, for example, 5 to 30 minutes may be elapsed before the bait 40 begins to flow out to the outside of the cage body 30.

[0059] When tuna are fed using a feeder, they begin feeding while the feed 40 is in the air. Therefore, it is thought that tuna become excited when feeding methods that throw the feed 40 from the air, such as using a feeder. On the other hand, with a feeding method that does not involve throwing the feed 40 from the air, as in the rearing method of this embodiment, the tuna 50 are less likely to become excited and can calmly consume the feed 40. Furthermore, with the rearing method of this embodiment, the impact noise generated when the feed 40 falls from the water surface can also be reduced. Due to these factors, the tuna 50 can consume the feed 40 without wasting energy, allowing them to grow efficiently. Therefore, tuna farming or aquaculture can be carried out efficiently.

[0060] With the rearing method of this embodiment, tuna 50 can be fed without workers having to throw in feed or operate a feeding machine. Since feeding continues as the ice blocks melt, the workload for feeding can be greatly reduced, and the actual working time can be greatly shortened. In this way, the rearing method of this embodiment also contributes to labor saving.

[0061] The swimming speed of the tuna 50 in the fish farm 70 may be 2.0 km / h or less, 1.5 km / h or less, 1.0 km / h or less, or 0.5 km / h or less. This allows the tuna 50 to grow sufficiently efficiently. The swimming speed of the tuna 50 during feeding may also be within the above range. The swimming speed of the tuna 50 can be measured, for example, using an underwater camera installed in the fish farm 70.

[0062] Once feeding is complete, the feeding device 10 is moved from the center of the fish farm 70 to near the outer edge. The feeding device 10 can be moved in the same manner as when it was moved to the center of the fish farm 70. After the feeding device 10 has been moved, the ice blocks 60 (ice blocks 60A) are placed back into the cage 30, and the feeding of the tuna 50 is repeated using the same procedure.

[0063] The seawater temperature in the fish farm 70 may be 12-30°C, 15-27°C, or 18-26°C. This allows the tuna 50 to feed sufficiently, thus enabling them to fatten up more efficiently. The feed 40 may include feed fish. This allows the tuna 50 to fatten up more efficiently. The size of the feed fish may be, for example, 100-300g.

[0064] <Obesity of Tuna> The obesity of tuna 50 may be 19 or higher, 20 or higher, or 22 or higher. Such tuna 50 have high commercial value. With the above-described rearing method, tuna 50 can be fattened efficiently. Therefore, tuna 50 with the above-described obesity can be obtained. The obesity is calculated using the following formula after the tuna has been processed into GG tuna. GG tuna refers to tuna in which the gills and internal organs have been removed. The internal organs specifically include the gills, stomach, intestines, liver, pyloric caeca, gonads (testes or ovaries), spleen, heart, and swim bladder. In the formula, W represents the weight (kg) of the GG tuna, and F represents the fork length (cm). Obesity = W × 10 ６ / F ３

[0065] Although several embodiments have been described above, the present invention is not limited in any way to the embodiments described above.

[0066] According to one aspect of this disclosure, a tuna feeding device and rearing facility that enable efficient farming or aquaculture of tuna are provided. According to one aspect of this disclosure, a tuna rearing method that enables efficient farming or aquaculture of tuna is provided. According to one aspect of this disclosure, tuna that are efficiently farmed or aquacultured and have sufficiently high commercial value are provided.

[0067] 10, 10A, 10C... Feeding device, 20... Floating body, 22... Raft, 22A... First rod-shaped member, 22B... Second rod-shaped member, 24... Float, 30, 30A, 30B, 30C... Cage body, 35... Side part, 36... Bottom part, 38... Frame body, 38A... Frame part, 38B... Pillar part, 40... Bait, 50... Tuna, 60, 60A, 61, 62, 63, 64, 65... Ice block, 70... Fish pen, 71... Fish pen body, 72... Net body, 74... Float, 76... Rope, 80... Filter, 80A, 80C, 80D... Bottom filter, 80S, 80B... Side filter, 86... Slit material, 87... Gap, 90... Sea, 95... Service area, 100... Rearing equipment.

Claims

1. A tuna rearing facility comprising a fish farm for raising tuna, and a feeding device having a cage body configured to hold a plurality of ice blocks, each containing feed, wherein the cage body prevents the tuna from entering and has an opening through which the feed can pass, and the plurality of ice blocks include at least two ice blocks of different sizes.

2. A tuna rearing facility comprising a fish farm for raising tuna, a cage body configured to hold ice blocks containing feed within the fish farm, and a feeding device having a frame body that supports the cage body, wherein the cage body prevents the tuna from entering and has an opening through which the feed can pass.

3. A tuna rearing facility comprising a fish farm for raising tuna and a feeding device having a cage body configured to hold ice blocks containing feed within the fish farm, wherein the cage body prevents the entry of the tuna and has openings through which the feed can pass, and the size of the openings in the cage body is non-uniform.

4. The tuna rearing facility according to any one of claims 1 to 3, wherein the cage body comprises a side filter surrounding the ice block and a bottom filter through which the feed separated from the ice block passes, and the bottom filter has a first opening through which the feed can pass and a second opening smaller than the first opening.

5. The tuna rearing facility according to claim 4, wherein the side filter has a third opening having a size that allows the bait separated from the ice mass to pass through to the surface layer of the sea, and a fourth opening that is smaller than the third opening.

6. The tuna rearing facility according to claim 4, wherein the opening in the side filter is smaller than the first opening.

7. The tuna rearing facility according to any one of claims 1 to 3, wherein the cage has sheet members on the sides surrounding the ice block.

8. The tuna rearing facility according to claim 2, wherein the cage body comprises a side filter surrounding the ice block and a bottom filter through which the feed separated from the ice block passes, and at least the bottom filter is fixed to the frame body under tension.

9. The tuna rearing facility according to any one of claims 1 to 3, wherein the feeding device is configured to be movable within the fish pen, and when feeding, it is positioned closer to the center of the fish pen than to the outer edge.

10. The tuna rearing facility according to claim 1, wherein each of the plurality of ice blocks contains a plurality of feeds, including the feed.

11. The tuna rearing facility according to claim 2 or 3, wherein the ice block contains a plurality of feeds, including the feed.

12. A method for raising tuna, comprising the step of feeding the feed from the feeding device in a breeding facility according to any one of claims 1 to 3.

13. A method for raising tuna, comprising the step of feeding tuna in a fish farm using a feeding device equipped with a cage body configured to hold a plurality of ice blocks, each containing bait, wherein the cage body prevents the entry of tuna and has an opening through which the bait can pass, and the plurality of ice blocks include at least two ice blocks of different sizes.

14. A method for raising tuna, comprising the step of feeding tuna in a fish farm using a feeding device comprising a cage body configured to hold ice blocks containing bait within the fish farm, and a frame body supporting the cage body, wherein the cage body prevents tuna from entering and has an opening through which the bait can pass.

15. A method for raising tuna, comprising the step of feeding tuna in a fish farm using a feeding device equipped with a cage body configured to hold a plurality of ice blocks, each containing bait, wherein the cage body prevents the entry of tuna and has an opening through which the bait can pass, and the size of the opening of the cage body is non-uniform.

16. A method for raising tuna in which their swimming speed is 2.0 km / hour or less.

17. Tuna species with a body mass index of 19 or higher.

18. A tuna feeding device comprising a cage body configured to hold a plurality of ice blocks, each containing tuna bait, and a float for floating the cage body in water, wherein the cage body prevents the entry of the tuna and has an opening through which the bait can pass, and the plurality of ice blocks include at least two ice blocks of different sizes.

19. A tuna feeding device comprising a cage body configured to hold ice blocks containing tuna bait, a float for floating the cage body in water, and a frame body for supporting the cage body, wherein the cage body prevents the entry of tuna and has an opening through which the bait can pass.

20. A tuna feeding device comprising a cage body configured to hold ice blocks containing tuna bait, and a float for floating the cage body in water, wherein the cage body has an opening that prevents tuna from entering and allows the bait to pass through, and the size of the opening in the cage body is non-uniform.

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