JP2012217404A - Larval fish rearing material and floating tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain worsening of a larval fish rearing environment due to overcrowding of larval fish in a lower layer of a water tank.SOLUTION: The larval fish rearing material 1 is a cylindrical body 10 with the inside used as a larval fish rearing space. An upper half part 10A of the cylindrical body 10 includes window parts 11 having openings 11A of set size, and a lower half part 10B of the cylindrical body 10 includes a net part 12 having mesh 12A of set size. The size of the opening 11A of the window part 11 is larger than that of the mesh 12A of the net part 12.

Description

  The present invention relates to a larva growing material used for growing larvae in the growth of salmon and trout and the like, and a levitation tank using the larva growing material.

  In the artificial propagation of migratory fish such as salmon and trout, a method has been used for a long time to hatch egg eggs with a hatcher and transfer the hatched larvae to a fish pond. On the other hand, a facility called a levitation tank, which performs everything from hatching eggs to breeding and levitation in one water tank, has become widespread. When this levitation tank is used, a large space such as a fish pond is not required, and hatching to larval management can be performed more easily.

  Here, “larva” refers to a fish that has just hatched and has a bag of nutrients called “saino” that has grown. The larva grows almost without moving because it does not feed and grows only with the nutrients in the citrus. The state where the nutrients of Saito are consumed and moved around to search for food is called “floating”, and the subsequent growth stage is called “fry” to distinguish it from larvae.

  In the conventional levitation tank, a growing material called a net ring is arranged in the water tank in order to secure a larval growth space. The net ring is a cylindrical member formed of a net material, and a plurality of these members are arranged and stacked in a water tank to form a larva growing space.

  In addition, in the conventional levitation tank, water is supplied from the bottom of the net ring and water is directed from the bottom to the top of the stacked net ring due to the placement of the eggs before hatching on the net ring. It has a flowing structure (see Patent Document 1 below).

No. 4-6544

  The net ring used in conventional levitation tanks has a uniform mesh size, and the size of the net ring can be entered and exited when the larva is oriented vertically, and entry and exit is restricted when the larva is oriented sideways. It is a size. When such a net ring is stacked in the aquarium, the hatched larvae try to take in oxygen with the head facing the upstream side of the water flow, so the water is flowing from the bottom of the net ring to the top Then, the phenomenon that larvae gather in the lower net ring occurs. If this phenomenon progresses excessively, the larvae will be concentrated in the net ring of the lower layer, and the flow of water will be stopped by the dense larvae, so there is a problem that it is not possible to give enough oxygen to many larvae Arise.

  By reducing the net ring mesh, it is possible to suppress the movement of the larvae to the lower layer, but if the net is small, the fish in the net ring will be removed when the fish is moved from the floating tank after growth. It becomes difficult to take it out. Further, when the net ring is taken out from the water tank and the fish is forced out of the net ring, there is a problem that the fish is easily damaged by the net of the net ring.

  This invention makes it an example of a subject to cope with such a problem. That is, for the purpose of the present invention, it is possible to suppress the deterioration of the environment for raising larvae due to the concentration of larvae in the lower layer of the aquarium, and to move the fish from the aquarium without damaging the fish when ascending. is there.

  In order to achieve such an object, the present invention comprises at least the following configuration.

  In order to grow larvae hatched from eggs, it is a larvae breeding material that is stacked in a water tank, and the inside is a cylindrical body that serves as a larval growth space, and the upper half of the cylindrical body is set And a lower half of the cylindrical body is provided with a mesh part having a mesh of a set size, and the size of the opening of the window part is determined by the mesh of the mesh part. It is characterized by being larger than the size.

  A levitation tank using such a larva growing material, wherein a pair of left and right weir plates are detachably provided in the water tank, and the larva growing materials are arranged and stacked between the dam plates, and the larva growing material The longitudinal direction of the cylindrical body is arranged along the direction in which the pair of left and right weir plates are opposed to each other, and water is supplied into the aquarium from a water supply port provided on the bottom surface of the aquarium, thereby raising the larvae Water is allowed to flow from the bottom to the top of the material, and drainage is performed through the pair of left and right barrier plates.

  According to the larva breeding material having such characteristics, the hatched larva enters the cylindrical body through the opening of the window provided in the upper half of the cylindrical body, but the lower half of the cylindrical body The larvae that have settled in the net are restricted from moving to the lower layers. As a result, the larvae are sequentially accommodated in the cylindrical body from the upper layer of the laminated larva growing material, and the larvae overflowing from the upper cylindrical body exit from the opening of the window part and are accommodated in the lower cylindrical body. The larvae can be distributed almost evenly from the upper layer to the lower layer of the larvae breeding material. Thereby, it can suppress that a larva gathers in the lower layer of a water tank, and the breeding environment of a larva deteriorates.

  Moreover, since the fish which stayed in the cylindrical body goes out from the opening of a comparatively large window part at the time of ascent, fish can be easily taken out from the larva breeding material.

  Furthermore, according to the levitation tank having the above-described characteristics, when ascending, by removing the pair of left and right barrier plates, the fish (fry) in the tubular body swims in the drainage space in the aquarium, and the drainage path is used. It becomes possible to move fish. Thus, the fish can be moved without forcibly removing the fish from the larva breeding material, and the fish can be moved from the aquarium to another facility without damaging the fish.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing (the figure (a) is an expansion perspective view, the figure (b) is a whole side view) which showed the larva breeding material which concerns on one Embodiment of this invention. It is explanatory drawing explaining the function of the larva growing material which concerns on one Embodiment of this invention. It is explanatory drawing which showed the other form example of the larva breeding material which concerns on embodiment of this invention. Explanatory drawing which showed the floating tank which concerns on embodiment of this invention (the figure (a) is explanatory drawing of planar view, the figure (b) is X1-X1 sectional drawing, the figure (c) is X2-X2 sectional drawing ).

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory view showing a larva growing material according to an embodiment of the present invention (FIG. 1 (a) is an enlarged perspective view, and FIG. 1 (b) is an overall side view). The larva growing material 1 according to the embodiment of the present invention is a cylindrical body 10 whose inside is a larval growing space, and the upper half 10A of the cylindrical body 10 is a window having an opening 11A of a set size. The lower half part 10B of the cylindrical body 10 is provided with a mesh part 12 having a mesh 12A of a set size. In the illustrated example, the cylindrical body 10 is a cylindrical member, but is not limited thereto, and may be a rectangular cylindrical shape. Further, in the illustrated example, the opening 11 </ b> A of the window portion 11 is partitioned by a horizontal frame 13 along the longitudinal direction of the cylindrical body 10 and a vertical frame 14 provided in a plurality at set intervals along the circumferential direction of the cylindrical body 10. ing.

  Here, the size (area) of the opening 11 </ b> A of the window portion 11 is larger than the size (area) of the mesh 12 </ b> A of the mesh portion 12. In the illustrated example, the shape of the opening 11A and the mesh 12A is rectangular. However, the shape is not limited to this, and may be circular or elliptical. The size of the opening 11A of the window portion 11 is a size that does not restrict the entry and exit of larvae, and the size of the mesh 12A of the mesh portion 12 is the size that restricts the entry and exit of larvae. More specifically, the size of the opening 11A is set to a size that allows the larvae to freely enter and exit, and the size of the mesh 12A is set to a size that prevents the larvae from passing through even when they are in a vertical orientation.

  The function of the larva growing material having such a configuration will be described with reference to FIG. The larva breeding material 1 is stacked in a water tank to grow larvae hatched from eggs, and a water flow W from the bottom to the top is formed in the water tank. ing. The hatched larva falls from above the aquarium and enters the cylindrical body 10 through the opening 11A of the window 11 provided in the upper half 10A of the cylindrical body 10 as shown by the arrow S1 in the drawing. And when the growth space in the cylindrical body 10 is vacant, the larva fits in the net | network part 12 provided in the lower half part 10B of the cylindrical body 10, and the accommodated larva moves to the lower layer from there To be regulated. Further, when larvae are already present in the growing space in the cylindrical body 10, even if the larvae enter the cylindrical body 10 through the opening 11A of the window 11, as shown by the arrow S2 in the figure, The larva is again taken out through the opening 11A and enters the cylindrical body 10 through the opening 11A in the lower cylindrical body 10 as indicated by an arrow S3.

  By repeating such an operation, the larvae are successively contained in the cylindrical body 10 from the upper layer of the stacked larvae breeding material 1, and the larvae overflowing from the upper cylindrical body 10 emerge from the opening 11A of the window 11. Therefore, the larvae can be distributed almost evenly from the upper layer to the lower layer of the laminated larva growing material 1. Thereby, it can suppress that a larva gathers in the lower layer of a water tank, and the breeding environment of a larva deteriorates.

  As shown in FIG. 2, the larva growing material 1 is preferably stacked so that the upper larva growing material 1 is placed between two larva growing materials 1 arranged in one layer. By laminating the larva growing material 1 in this way, it is possible to ensure a wider movement path for the larvae that have come out of the window 11 to enter the window 11 of the lower larva growing material 1.

  Drawing 3 is an explanatory view showing other examples of larva breeding material 1 concerning an embodiment of the present invention. In this example, the larva growing material 1 is provided with a plate-like partition body 20 that partitions the internal space of the tubular body 10 inside the tubular body 10. The partition body 20 has a spiral partition surface 20 </ b> A that extends along the longitudinal direction of the tubular body 10 and is twisted around the central axis of the tubular body 10, as shown in FIG. Or a disc-shaped partition surface 20B that is arranged at set intervals along the longitudinal direction of the tubular body 10 and intersects the longitudinal direction of the tubular body 10 as shown in FIG. It may have.

  By providing such a partition body 20, the space in the tubular body 10 can be partitioned into a space where a single larvae can easily be present, and there is a problem that the larva concentrates at a specific location in one tubular body 10. Can be resolved. Thereby, a better breeding environment can be given to the larvae. The form of the partition 20 is not limited to the example shown in FIG. 3, and any form may be used as long as larvae are dispersedly arranged in the tubular body 10.

  4A and 4B are explanatory views showing the levitation tank according to the embodiment of the present invention (FIG. 4A is an explanatory view in plan view, FIG. 4B is a sectional view taken along line X1-X1, and FIG. 4C is X2). -X2 sectional view). The levitation tank 30 is obtained by laminating the larva breeding material 1 described above in a water tank 31. In the water tank 31, a pair of left and right weir plates 32, 32 are detachably provided. The inside of the aquarium 31 is partitioned by the barrier plates 32, 32. In a plan view, the inside of the pair of barrier plates 32, 32 becomes a hatching / larva breeding space A, and both outer sides of the pair of barrier plates 32, 32 are It is a drainage space B.

  In the hatching / larvae breeding space A between the barrier plates 32, 32, the larvae breeding material 1 is arranged and stacked, and the larvae breeding material 1 extends along the direction in which the pair of left and right dam plates 32, 32 face each other. The longitudinal direction of the cylindrical body 10 is arranged.

  The hatching / larvae breeding space A provided between the pair of barrier plates 32 and 32 is divided into a lower layer space C, an intermediate layer space D, and an upper layer space E by two net members 33 and 34. The lower layer space C is a space for rectifying the water flow, the intermediate layer space D is a larval breeding space, and the upper layer space E is a hatching space on which the laid eggs are placed. The larva growing material 1 described above is horizontally arranged and stacked in the intermediate layer space D between the net members 33 and 34.

  In the drainage space B, a water diffusion plate 40 is provided at almost the same height as the net member 33, and a drain outlet 36 is provided in the water diffusion plate 40. A drain pipe 38 is connected to the drain port 36.

  A plurality of water supply ports 35 are provided on the bottom surface of the water tank 31. The water supply port 35 is provided so as to face the water diffusion plate 40, and a water supply pipe 37 is connected to the water supply port 35.

  The levitation tank 30 supplies water into the water tank 31 from the water supply port 35 provided on the bottom surface of the water tank 31, so that the water flowing out from the water supply port 35 hits the water diffusion plate 40 and is diffused in the lower space C. The flow of water is rectified, and water flows from the lower side of the larva growing material 1 upward. Then, drainage is performed through the pair of left and right weir plates 32, 32. The water that flows into the drainage space B through the pair of left and right weir plates 32, 32 flows into the drainage pipe 38 from the drainage port 36.

  A method of using the levitation tank 30 will be described. First, as shown in FIG. 4 (b), the water level in the hatching / larvae breeding space A is increased to the vicinity of the upper ends of the barrier plates 32, 32, and the egg is placed on the net material 34. After hatching has progressed and all the larvae have fallen into the intermediate layer space (growing space) D after passing through the net member 34, the upper 32A of the barrier plates 32, 32 is removed to lower the water level, and the net member 34 is removed. The larvae are cultivated in the larva breeding material 1 arranged in the intermediate layer space (cultivation space) D.

  At this time, since the water rectified in the lower layer space C flows from the bottom to the top and flows toward the left and right drainage spaces B, the flow of water in the intermediate layer space D is as follows. A relatively uniform water flow is obtained. Thereby, fresh water containing oxygen can be evenly supplied to the larvae in the larva breeding material 1.

  Thereafter, when the fish begins to rise, the water level adjusting pipe 39 is attached to the drain port 36, the entire water level in the water tank 31 is set to a water level in which the intermediate layer space D is completely immersed, and the barrier plates 32 and 32 are removed from the water tank 31. By doing in this way, the fish staying in the larva breeding material 1 will naturally move to the drainage space B in the aquarium 31, and the fish together with the drainage from the upper end of the water level adjustment pipe 39 will be the water level adjustment pipe 39. And flows into the drainage pipe 38.

  According to such a levitation tank 30, since the larva is distributed almost uniformly in the larva growing material 1 stacked from the upper layer to the lower layer, the water supplied from below is a plurality of the larva growing material. The larvae in the larva growing material 1 can be grown in a good environment.

  Further, at the time of ascent, the grown fish can be moved out of the water tank 31 through the drain pipe 38 without removing the larva growing material 1. Thereby, it is possible to move the fish without forcibly expelling the fish from the larva growing material 1, and it is possible to move the fish out of the aquarium 31 without damaging the fish.

1: larva breeding material, 10: cylindrical body, 10A: upper half, 10B: lower half,
11: Window part, 11A: Opening, 12: Mesh part, 12A: Mesh,
20: Partition body, 20A, 20B: Partition surface,
30: Levitation tank, 31: Water tank, 32: Dam plate, 33, 34: Net material,
35: Water supply port, 36: Drainage port, 37: Water supply pipe, 38: Drainage pipe,
39: Water level adjusting pipe, 40: Water diffusion plate

Claims (8)

In order to grow larvae hatched from eggs, it is a larvae breeding material arranged in a water tank,
The inside is a cylindrical body that serves as a breeding space for larvae,
The upper half of the cylindrical body is provided with a window having an opening of a set size, and the lower half of the cylindrical body is provided with a mesh having a mesh of a set size, A larva growing material characterized in that the size of the opening is larger than the size of the mesh of the net part.   The size of the opening of the window portion is a size that does not restrict entry and exit of larvae, and the size of the mesh of the net portion is a size that restricts entry and exit of larvae. The larva breeding material described.   The opening of the window portion is partitioned by a horizontal frame along the longitudinal direction of the cylindrical body and a vertical frame provided at a set interval along the circumferential direction of the cylindrical body. The larva breeding material described.   The larvae breeding material according to claim 1 or 2, wherein a plate-like partition body for partitioning the internal space of the tubular body is provided inside the tubular body.   The larvae breeding material according to claim 4, wherein the partition body has a partition surface extending along a longitudinal direction of the cylindrical body and twisted around a central axis of the cylindrical body.   The said partition body is arrange | positioned for every set space | interval along the longitudinal direction of the said cylindrical body, and has a partition surface which cross | intersects the longitudinal direction of the said cylindrical body, The larva growing material of Claim 4 characterized by the above-mentioned.   A levitation tank in which the larvae breeding material according to any one of claims 1 to 6 is laminated in a water tank. In the water tank, a pair of left and right weir plates are provided detachably,
Arranging and laminating the larva breeding material between the barrier plates,
The larva growing material is arranged in a longitudinal direction of the cylindrical body along a direction in which the pair of left and right barrier plates are opposed to each other.
By supplying water into the water tank from the water supply port provided on the bottom surface of the water tank, water flows from the bottom to the top of the larva breeding material, and drains through the pair of left and right barrier plates. The levitation tank according to claim 7, wherein

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