JP2010081817A - Spawning bed for oryzias latipes and method for spawning of oryzias latipes - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spawning bed for Oryzias latipes, which has a simple structure, but enhances the spawning rate of the Oryzias latipes and is excellent in handleability, and to provide a method for the spawning of the Oryzias latipes with the spawning bed. <P>SOLUTION: There is provided the spawning bed 14 for the Oryzias latipes, comprising a spawning bed 10 and a floating member 12 for placing the spawning bed 10 below the surface of water, characterized by forming the spawning bed 10 from a net-like member 10a, controlling the opening values (t1) of the net-like member 10a within a range of 0.3 to 8 mm, and disposing Oryzias latipes-passing holes 10b having circle-corresponding diameters (t2) of 10 to 50 mm; and the method for spawning the Oryzias latipes with the spawning bed 14. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a spawning bed for medaka and a spawning method for medaka, and more particularly, a spawning bed for medaka having a high spawning rate and excellent usability even with a simple configuration by utilizing the habit of medaka. And a method for laying eggs of medaka using the same.

In the past, it has been related to the improvement of animal and plant ecosystems in lakes and rivers, especially improving water pollution, promoting the growth of microorganisms effective for water purification by the generation of plankton, and securing the habitat of aquatic insects and animals. A floating spawning bed that forms a spawning bed for fish such as ayu and bluegill has been proposed (see, for example, Patent Document 1).
More specifically, as shown in FIG. 4, a floating structure 102 made of a columnar plant such as bamboo or wood, which exhibits sufficient buoyancy on the water surface, and a fiber material such as palm skin are mixed and laminated. And a spawning bed main body 104 entangled with and integrated with the floating lattice frame 103 of the floating structure 102 so as to have a predetermined thickness and density. It is as a structure.

In addition, a breeding / cultivation system for performing black medaka and shurogayatsuri in the same water tank has been proposed (for example, see Patent Document 2).
More specifically, as shown in FIG. 5, a rearing / cultivation system for cultivating a black shrimp 203 near the surface of the aquarium 201 while rearing a black medaka 202 under the surface of the aquarium 201, 204 is formed in a flask shape with a spherical shape and an upper portion 205 with a thin cylindrical shape, and the lower end of the thin cylindrical portion is configured to be slightly narrowed.

Furthermore, a breeding system using a pseudo-water hyacinth for medaka spawning has been proposed so that the medaka can be viewed at a desired time and the medaka can be spawned and hatched (see, for example, Patent Document 3).
More specifically, as shown in FIG. 6, the pseudo water hyacinth 302 is floated at the time of spawning of the medaka 301, and spawning is promoted to the pseudo water hyacinth root 303, and around the pseudo water hyacinth root 303, Although not shown in the figure, a Velcro tape (registered trademark) is wound around.
JP 2000-188991 A JP 2004-261161 A JP 2004-337140 A

However, the floating egg-laying bed disclosed in Patent Document 1 needs to be suspended in a lake or a river, so that there is a problem that the configuration becomes complicated or the size becomes large and the handling is not easy. It was. In particular, in the case of breeding medaka, it is necessary to move the floating spawning bed to isolate it from the parent medaka after spawning. However, the floating spawning bed disclosed in Patent Document 1 cannot be easily moved. It was.
Moreover, since it is a large spawning bed main body which cross-stacked fiber materials, such as palm skin, the problem that it was not suitable for spawning of a medaka was seen.
In other words, if medaka and spawning bed are not separated immediately after spawning, medaka has the habit of eating spawned eggs, although it was required to move the spawning bed easily and quickly. However, there was a problem that it could not be adapted to it.

Moreover, the breeding / cultivation system disclosed in Patent Document 2 has to use a flask-like water tank, and there is a problem in that there are large restrictions on the size and form of the water tank.
In addition, because it is a spawning bed body consisting of the shurogayatsuri itself, there was a problem that the spawning efficiency of the medaka was low and it was difficult to recognize it due to the color of the egg of the spawning medaka.

Furthermore, the breeding system using the pseudo-water hyacinth for spawning medaka disclosed in Patent Document 3 must use the pseudo-water hyacinth, which makes the configuration complicated and makes it difficult to stably produce it. There was a problem.
In addition, although magic tape (registered trademark) was wrapped around the root of the pseudo water hyacinth, there was a problem that the spawning efficiency of medaka was still low.

Therefore, as a result of intensive studies by the inventors of the present invention, the egg-laying bed is composed of a member having a predetermined opening diameter, and a high egg-laying rate is obtained by providing a passage hole for a medaka having a predetermined diameter. In addition, the present invention has been completed by finding that it is easy to use by combining with a predetermined floating member.
That is, the present invention makes use of the habit that medaka rubs the body against the spawning bed to lay eggs and easily enters a predetermined opening location, and even with a simple configuration, the medaka has a high egg-laying rate. And it aims at providing the egg-laying bed for medaka which was excellent in usability by combining with a predetermined floating member, and the egg-laying method of medaka using the same.

  According to the present invention, a spawning bed for medaka including a spawning bed and a floating member for positioning the spawning bed below the water surface, wherein the spawning bed is composed of a reticulated member, and the reticulated Provided is a spawning bed for medaka characterized in that the opening diameter of the member is set to a value within the range of 0.3 to 8 mm and a passage hole for the medaka having an equivalent circle diameter of 10 to 50 mm is provided. Can be solved.

That is, the spawning bed for medaka includes a spawning bed having a predetermined structure and a floating member for reliably positioning the spawning bed below the water surface, so that a simple configuration can be obtained. In addition, it is lightweight and can be used with excellent usability.
For example, with such a spawning bed for medaka, immediately after spawning, the spawning bed can be easily and quickly moved to effectively separate the medaka from the spawning bed.
Moreover, if it is such a spawning bed for medaka, a plurality of them can be prepared and used independently or in a connected state in one water tank. Therefore, depending on the degree of egg laying, it can be transferred to a separate aquarium as a spawning bed for individual medaka and hatched there, so that the manageability for breeding medaka is significantly improved.

In addition, the spawning bed is composed of a net-like member, the opening diameter of the net-like member is a value within a predetermined range, and the diameter equivalent to the circle has a medaka passage hole,
Since the medaka easily enters the passage hole and the medaka easily rubs the body, a high egg-laying rate can be obtained.
Furthermore, the spawning bed is equipped with a passage hole of a predetermined size, so that there is a habit of medaka that goes out and enters the passage hole, and the movement of the medaka becomes active and the appreciation is also enhanced. Can do.
In addition, the actively moving male and female medakas are interested in each other, resulting in higher egg-laying rates.

In constructing the spawning bed for medaka of the present invention, it is preferable that the net-like member is a strip-like shape, and the strip-like net-like member is rounded to form a loop to be a medaka passage hole.
By comprising in this way, the passage hole of a medaka can be formed efficiently and simply, it becomes easier for a medaka to penetrate | invade into a passage hole, and a higher egg-laying rate can be obtained.
In addition, while rounding the strip-shaped mesh member, it is easy to make a loop of a predetermined size, and in order to easily maintain the shape as it is, on one side or both sides of the strip-shaped mesh member, It is also preferable to provide a cut of a predetermined length along.

Moreover, when composing the spawning bed for medaka of the present invention, it is preferable to set the number of medaka passage holes provided in the spawning bed within a range of 2 to 6.
By providing a plurality of medaka passage holes in this manner, it becomes possible for a plurality of medakas to lay eggs at the same time, and the egg-laying rate of medaka can be further increased.

Moreover, when composing the spawning bed for medaka of the present invention, it is preferable that the color of the spawning bed is blue or black.
With such a color of the egg-laying bed, the medaka can be laid with peace of mind without physiological repulsion.
On the other hand, since the color of medaka eggs is usually light yellowish green, if the color of the laying bed is blue, the medaka egg laid on the laying bed can be visually confirmed. Therefore, immediately after spawning, the spawning bed can be moved to the outside of the water tank, and the medaka and the spawning bed can be reliably separated.

Moreover, when comprising the spawning bed for medaka of this invention, it is preferable to comprise a floating member from a polystyrene foam.
If it is such a floating member, since it shades appropriately and forms a shade under it, medaka lays eggs in peace with respect to the spawning bed provided below without physiological repulsion be able to.
In addition, such a floating member is not only excellent in water repellency and economy, but also can be easily attached with a sign, an identification member, and the like.

Moreover, in constructing the spawning bed for medaka of the present invention, it is preferable that the floating member has a plate shape.
With such a floating member, the egg-laying bed can be accurately placed at a predetermined position below the water surface, and handling after egg-laying is facilitated.
Moreover, if it is such a plate-shaped floating member, the vertical hole and taper hole which follow a water surface can be provided easily. Therefore, by feeding the food from there, it is possible to concentrate the food in the vicinity of the spawning bed, to increase the concentration on the medaka, and to further increase the egg-laying rate.

Moreover, when composing the spawning bed for medaka of the present invention, it is preferable that the spawning bed and the floating member are connected via a connecting member.
With this configuration, the egg-laying bed and the floating member can be firmly and simply connected, and the connecting member functions as a weight, and the egg-laying bed is accurately placed at a predetermined position below the water surface. be able to.
In addition, it is more preferable that it is a metal connection member made of stainless steel or aluminum so as not to rust in water.

Another aspect of the present invention is a method for laying a medaka using a laying bed for medaka, which includes a laying bed and a floating member for positioning the laying bed below the water surface,
For the medaka which comprises a spawning bed composed of a mesh member, the opening diameter of the mesh member is a value within the range of 0.3 to 8 mm, and a through hole for the medaka having a circle equivalent diameter of 10 to 50 mm is provided. Preparing a spawning bed;
A step of containing a spawning bed for medaka and a medaka in a water tank;
A step of growing medaka under a water temperature of 10 to 40 ° C .;
It is a spawning method of the medaka characterized by including.
That is, the spawning bed is composed of a net-like member, the opening diameter of the net-like member is set to a value within a predetermined range, and the equivalent diameter of the medaka has a predetermined hole, and the spawning bed is placed on the water surface. By using a medaka egg-laying bed including a floating member to be positioned below, a high egg-laying rate can be obtained by utilizing the medaka habit.

[First embodiment]
As illustrated in FIGS. 1 to 3, the first embodiment is a spawning bed 14 for medaka that includes a spawning bed 10 and a floating member 12 for positioning the spawning bed 10 below the water surface. The egg-laying bed 10 is composed of the mesh member 10a, the opening diameter (t1) of the mesh member 10a is set to a value in the range of 0.3 to 8 mm, and the equivalent circle diameter (t2) is 10 to 10. A medaka spawning bed 14 provided with a medaka passage hole 10b having a diameter of 50 mm.

1 (a) to 1 (b) show photographs of the medaka spawning bed 14 having one medaka passage hole 10b made of a predetermined mesh member 10a, and FIGS. b) shows a photograph of the medaka spawning bed 14 having three medaka passage holes 10b made of a predetermined mesh member 10a, and FIGS. 3 (a) to 3 (b) show a predetermined mesh shape. The medaka passage hole 10b made of the member 10a shows a photograph of the half-loop medaka spawning bed 14.
Hereinafter, the laying bed for medaka according to the first embodiment will be specifically described by dividing into a laying bed and a floating member.

1. Spawning bed (1) mesh member First, the spawning bed 10 illustrated in FIG. 1 and the like is composed of a mesh member (sometimes referred to as a net member) 10a and its opening diameter (t1) is 0.3 to 0.3. The value is within a range of 8 mm.
The reason for this is that if the mesh member has such an opening diameter, the medaka can easily rub the body regardless of the size and type of the medaka, and the laid eggs can easily adhere.

More specifically, when the opening diameter is less than 0.3 mm, it is difficult for the medaka to rub the body or the laid eggs are likely to fall. In particular, in a medaka having a large body length or a medaka having a partially large head or tail fin, it is difficult to rub the body against a net-like member having an excessively small opening diameter.
On the other hand, even if the opening diameter exceeds 8 mm, it is difficult for the medaka to rub the body or the laid eggs are likely to fall. In particular, in the case of a medaka having a body length of about 2 to 6 mm or less, it is difficult to rub the body against a net-like member having an excessively large opening diameter.
Therefore, the opening diameter of the mesh member is preferably set to a value within the range of 0.6 to 6 mm, more preferably set to a value within the range of 1 to 5 mm, and a value within the range of 2 to 4 mm. Is more preferable.

As shown in FIGS. 1 and 2, the opening diameter (t1) of the mesh member 10a means the average value of the lengths of the diagonal lines at several locations when the opening shape is approximately square, and the opening shape is approximately In the case of a circle or an ellipse, it means an average value of diameters and major axes at several locations.
Therefore, as the opening diameter of the mesh member, for example, it is possible to directly measure three or more locations using a caliper, and to adopt the average value, or to measure three or more locations as a micrograph with a scale, Then, the average value can also be calculated indirectly.

(2) Color The color of the egg-laying bed 10 illustrated in FIG. 1 and the like is not particularly limited, but is preferably blue or black, for example.
The reason for this is that medaka can lay eggs safely without physiological repulsion if the color of such a spawning bed is used.
On the other hand, the color of medaka eggs is usually light yellowish green, so if the color of the laying bed is blue or black, the medaka eggs laid on the laying bed can be visually confirmed. This is because it can.
Conversely, if the color of the egg-laying bed 10 is green, yellow, or transparent, it may be difficult to visually confirm the medaka eggs laid on the egg-laying bed.

In addition, regarding the color of the spawning bed, the whole mesh member constituting the spawning bed may be colored, or only the planned spawning portion of the mesh member constituting the spawning bed may be partially colored. good.
Further, in coloring the egg-laying bed, a coloring agent (including a fluorescent agent) may be added to the constituent material of the mesh member, or only the periphery of the constituent material of the mesh member may be colored.

(3) Material The material of the mesh member 10a constituting the egg-laying bed 10 illustrated in FIG. 1 and the like is not particularly limited. For example, amide resin, olefin resin (polyethylene resin, polypropylene resin, etc.), It is preferably at least one of acrylic resin, vinyl chloride resin, cellulose resin, urethane resin and the like.
In particular, an amide resin or an olefin resin is a preferable material because it is lightweight, easily maintains a predetermined shape in water, is inexpensive, and has excellent durability.

(4) Medaka Passing Hole Further, the spawning bed 10 illustrated in FIG. 1 and the like is characterized by providing a medaka passing hole 10b having an equivalent circle diameter of 10 to 50 mm.
The reason for this is that by providing a passage hole having such a circle-equivalent diameter, it becomes easy to enter the inside regardless of its size due to the nature of the medaka, and it becomes easy to rest and lay eggs in it. Because.

More specifically, when the equivalent circle diameter is less than 10 mm, it is difficult for medaka to invade and the egg-laying rate is significantly reduced.
On the other hand, if the equivalent circle diameter exceeds 50 mm, the medaka is less likely to enter or rest.
Accordingly, the medaka passage hole is preferably set to a value within the range of 15 to 45 mm, more preferably set to a value within the range of 20 to 40 mm, and further preferably set to a value within the range of 25 to 35 mm. .

The equivalent circle diameter of the medaka passage hole means an average value of the lengths of the diagonal lines when the opening shape is substantially square. As shown in FIGS. In the case of an ellipse, it means an average value at a plurality of locations of the diameter or major axis.
Further, when the passage hole of the medaka is a half loop as shown in FIG. 3 and the opening shape is a substantially semicircle, it means an average value at a plurality of locations of the radius.
Therefore, as the equivalent circle diameter of the medaka passage hole, for example, it is possible to directly measure three or more places using a caliper and adopt the average value, or three or more places as a micrograph with a scale. It is also possible to measure and then indirectly calculate the average value.

Further, as shown in FIG. 1 and the like, the net-like member 10a is strip-shaped, and the strip-like net-like member 10a is rounded to form a loop (including a half loop), which is a medaka passage hole 10b. Is preferred.
The reason for this is that the medaka passage hole can be efficiently and easily formed by rounding the strip-shaped net-like member to form a loop (including a half-loop).
Accordingly, the medaka is more likely to enter the passage hole of the medaka that is a loop, and a higher egg-laying rate can be obtained.
As shown in FIG. 1 and the like, the strip-shaped net member is rounded to form a loop having a predetermined size, and on one side or both sides of the strip-shaped net member so as to be easily held as it is, a predetermined length is provided. It is also preferable to provide a notch.

Moreover, as shown in FIG. 2, it is preferable that the number of the through holes 10b of the medaka provided in the spawning bed 10 is 2-6.
The reason for this is that by providing a plurality of medaka passage holes, a plurality of medaka can invade at the same time, and the egg-laying rate of the medaka can be further increased.
That is, when the number of medaka passage holes is less than two, depending on the number of medaka, the egg-laying rate may decrease, whereas when the number of medaka passage holes exceeds six, This is because the size of the egg-laying bed becomes excessive, making handling difficult.
Therefore, the number of medaka passage holes provided in the spawning bed is more preferably 2 to 5, and further preferably 3 to 4.

2. Floating Member (1) Form As shown in FIG. 1 and the like, the form of the floating member 12 is not particularly limited. For example, a plate shape is preferable.
The reason for this is that such a floating member allows the egg-laying bed to be accurately placed at a predetermined position below the water surface and facilitates handling after egg-laying.
In addition, such a floating member is not only excellent in water repellency and economy, but also can be easily attached with a sign, an identification member, and the like.
Furthermore, with such a plate-like floating member, it is possible to easily provide a vertical hole or a taper hole following the water surface. Therefore, by feeding the food from there, it is possible to concentrate the food in the vicinity of the spawning bed, to increase the concentration on the medaka, and to further increase the egg-laying rate.
Therefore, when the floating member has a plate shape, the thickness is preferably set to a value in the range of 8 to 50 mm, more preferably set to a value in the range of 15 to 40 mm. More preferably, the thickness is set to a value within the range of 20 to 30 mm.
The planar shape of the floating member is not particularly limited, and may be, for example, a circle, an ellipse, a polygon, or an irregular shape.

(2) Material Moreover, it is preferable that the floating member 12 is comprised from the polystyrene foam so that it may illustrate in FIG.
The reason for this is that if it is such a floating member, it will shade appropriately and form a shade below it, so that the medaka will not repel physiologically, against the spawning bed provided below, This is because eggs can be laid in peace.
In addition, such a floating member is not only excellent in water repellency and economy, but also can be easily attached with a sign or an identification tag.
Examples of the floating member other than the polystyrene foam include a piece of wood, a plastic piece, a hollow ball, and a ship-shaped floating member.

3. Connecting Member In addition, as illustrated in FIG. 1 and the like, it is preferable that the egg-laying bed 10 and the floating member 12 are connected via a connecting member 16.
This is because the spawning bed and the floating member can be firmly and simply connected by such a configuration, and the connecting member functions as a weight so that the spawning bed is placed at a predetermined position below the water surface. This is because it can be arranged with high accuracy.
It is also preferable to extend the connecting member by a predetermined length so that it functions not only as a connection between the spawning bed and the floating member but also as a holding member for holding the spawning bed in a predetermined shape. That is, it is preferable that a part or the whole of the spawning bed composed of the mesh member is reinforced with the connecting member.

[Second Embodiment]
2nd Embodiment is a spawning method of the medaka using the spawning bed for medaka containing the spawning bed and the floating member for positioning the said spawning bed under the water surface, Comprising: A spawning bed is made from a net-like member. And a step of preparing a spawning bed for medaka provided with a passing hole for the medaka having an opening diameter of the mesh member of 0.3 to 8 mm and an equivalent circle diameter of 10 to 50 mm. An medaka egg-laying method comprising the steps of: housing a medaka egg-laying bed and a medaka fish in a water tank; and cultivating a medaka fish under a temperature condition of 10 to 40 ° C. .
Hereinafter, the medaka egg-laying method according to the second embodiment will be specifically described in each process.

1. Step for preparing a spawning bed for medaka This is a step for preparing the spawning bed for medaka described in the first embodiment. Therefore, the further description here about a spawning bed for medaka is omitted.

2. Medaka housing step This is a step of housing the medaka egg-laying bed described in the first embodiment and the medaka in a water tank of a predetermined size.
Here, the form of the water tank is not particularly limited, but for example, it is preferably a resin box container represented by styrene foam or olefin resin, or a glass box container.
Moreover, it is also preferable to provide an aeration apparatus, a temperature management apparatus, a cleaning apparatus, a light shielding apparatus, an illumination apparatus, etc. as an accessory of a water tank.

On the other hand, the kind of medaka to be accommodated in the water tank is not particularly limited, and may be, for example, one kind or a combination of two or more kinds of black medaka, medaka, aome medaka, white medaka, albino, transparent medaka.
Further, the size is not particularly limited, and for example, the body length is preferably a value within the range of 0.3 to 5 cm.

3. Medaka Breeding Process The medaka breeding process is a process of breeding medaka under a temperature condition of a water temperature of 10 to 40 ° C. as a predetermined temperature.
That is, for example, a process of cultivating a medaka for a predetermined period using a commercially available medaka feed under a temperature condition of a water temperature of 10 to 40 ° C. by operating an aeration apparatus and bubbling air while operating a temperature management apparatus. It is.
The reason for this is that when the water temperature is less than 10 ° C., depending on the kind of medaka, the movement is drastically reduced and the egg-laying rate may be significantly reduced. On the other hand, if the water temperature exceeds 40 ° C., it may exceed the viable range and may be killed or the egg-laying rate may be significantly reduced.
Therefore, in growing medaka, the water temperature is more preferably set to a value within the range of 15 to 30 ° C, and the water temperature is further preferably set to a value within the range of 20 to 28 ° C.

4). Spawning process of medaka The spawning process of medaka is a process of laying eggs on the spawning bed for medaka in the middle of growing medaka.
And when medaka lays eggs, it will be noted that immediately after laying eggs, the laying beds are moved to the outside of the water tank, and the medakas and laying beds are surely separated.
That is, because of the habit of medaka, the eggs laid may be eaten.
In this regard, the medaka spawning bed of the present invention has a simple structure and is light in weight, and therefore can easily handle moving the spawning bed to the outside of the water tank.
By setting the color of the egg-laying bed to blue or black, it is possible to obtain an effect that the medaka can lay eggs safely without causing physiological repulsion.
In addition, since the color of medaka eggs is usually light yellowish green, if the color of the laying bed is blue or black, the medaka eggs laid on the laying bed can be visually confirmed. It is possible to move the spawning bed to the outside of the water tank more quickly.

[Example 1]
1. Step for preparing a spawning bed for medaka A raw material of a blue mesh member (made of polypropylene resin) having an opening diameter of 4 mm was cut to prepare three strip members (vertical: 10 cm, horizontal: 3 cm).
In addition, cuts having a length of 1 cm were provided on both sides of the strip-shaped member at intervals of 2 cm.
Next, while forming a loop having an equivalent circle diameter of 30 mm, it was attached to a plate-like (length: 5 cm, width: 3 cm, thickness: 2 cm) styrofoam floating member with a wire having a diameter of 1 mm.
This was repeated in sequence, and three loops were formed as medaka passage holes, and the egg-laying bed for medaka of Example 1 was obtained.

2. Breeding process using a spawning bed for medaka A styrene foam water tank having a length of 30 cm, a width of 20 cm, and a depth of 18 cm was prepared, and 6000 cm ³ of well water (one day left in the sun) was accommodated.
Moreover, the aeration apparatus and the temperature management apparatus were arrange | positioned as an accessory in this water tank.
Next, 5 black medaka fish (2 males and 3 females) having a body length of about 3.5 cm are accommodated in the aquarium, and a commercially available medaka feed is used at a water temperature of 25 to 30 ° C. An egg-laying experiment was conducted for about one week.

3. Evaluation of spawning bed for medaka (1) Evaluation of spawning rate The number of spawning for one spawning bed for medaka was measured, and the spawning rate was evaluated according to the following criteria.
A: The number of eggs laid for one medaka spawning bed is 50 or more.
○: The number of eggs laid for one medaka spawning bed is 20 or more.
(Triangle | delta): The egg-laying number with respect to one spawning bed for medaka is five or more.
X: The number of eggs laid for one spawning bed for medaka is less than 5.

(2) Evaluation of activity of medaka The movement of medaka was visually observed through the passage hole of the medaka, and the activity of medaka was evaluated according to the following criteria.
(Double-circle): It can always recognize that all the medaka is moving.
○: It can be recognized for a long time that all the medaka are moving.
(Triangle | delta): It can recognize from time to time that all the medaka is moving.
X: It can hardly recognize that all medakas are moving.

(3) Evaluation of spawning recognition Eggs spawned by medaka were visually observed, and spawning recognition was evaluated according to the following criteria.
(Double-circle): The egg which the medaka spawned can be recognized notably and rapidly visually.
○: The eggs laid by the medaka can be fully recognized visually.
(Triangle | delta): The egg which the medaka spawned can be recognized substantially visually.
X: Eggs laid by medaka cannot be visually recognized.

(4) Mobility evaluation of medaka egg-laying bed The mobility of the medaka egg-laying bed after egg laying was evaluated according to the following criteria.
(Double-circle): The spawning bed for medaka after medaka spawns can be moved very rapidly.
○: The medaka spawning bed after the medaka has laid eggs can be moved quickly.
(Triangle | delta): If a medaka spawning bed after medaka lays eggs, it can move slowly.
X: The medaka spawning bed after the medaka has spawned cannot be moved.

[Examples 2 to 4]
In Examples 2 to 4, as shown in Table 1, by changing the opening diameter of the mesh member, the number of medaka passage holes, and the equivalent circle diameter of the medaka passage holes, The preparation process of the spawning bed, the breeding process using the spawning bed for medaka, and the spawning bed for medaka were carried out.

[Comparative Examples 1-3]
In Comparative Examples 1 to 3, as shown in Table 1, by changing the opening diameter of the mesh member, the number of through holes of the medaka, and the equivalent circle diameter of the through holes of the medaka, The preparation process of the spawning bed, the breeding process using the spawning bed for medaka, and the spawning bed for medaka were carried out.

[Comparative Example 4]
In Comparative Example 4, the medaka egg-laying bed shown in FIG. 5 was prepared, and as in Example 1, the breeding process using the medaka egg-laying bed and the evaluation of the medaka egg-laying bed were performed.

[Comparative Example 5]
In Comparative Example 5, the medaka egg-laying bed shown in FIG. 6 was prepared, and as in Example 1, the breeding process using the medaka egg-laying bed and the evaluation of the medaka egg-laying bed were performed.

As described above, according to the spawning bed for medaka of the present invention, it is possible to provide a spawning bed for medaka having a high spawning rate and excellent usability even with a simple configuration. became.
In particular, by using a blue or black medaka spawning bed, the medaka can be laid with peace of mind without physiological repulsion, and visually confirm the medaka eggs laid on the spawning bed. I was able to do that. Therefore, by using the spawning bed for medaka of a predetermined color, the spawning bed can be moved to the outside of the water tank immediately after spawning, and the medaka and the spawning bed can be reliably separated.

Further, according to the medaka egg-laying method using the medaka egg-laying bed of the present invention, the medaka egg-laying method is constituted by a mesh member, the opening diameter of the mesh member is set to a value within a predetermined range, and the equivalent circle diameter is predetermined. By using a spawning bed for a medaka that includes a spawning bed having a passing hole for a medaka that is a range and a floating member for positioning the spawning bed below the surface of the water, high spawning can be performed using the medaka's habits. You can get a rate.
Therefore, the medaka designated as an endangered species can be effectively propagated today, or it can be easily crossed to propagate the medaka for viewing and the like.

FIG. 1 (a)-(b) is a figure provided in order to demonstrate one (the passage hole of a medaka is one) of the spawning bed for medaka of this invention (photograph). 2 (a) to 2 (b) are diagrams (photographs) provided to explain one of the embodiments of the spawning bed for medaka according to the present invention (the medaka has three passage holes). FIGS. 3A to 3B are diagrams (photographs) provided to explain one of the embodiments of the spawning bed for medaka of the present invention (the medaka passage hole is a half loop). FIG. 4 is a diagram for explaining one of the conventional floating spawning beds. FIG. 5 is a diagram for explaining a conventional breeding / cultivation system in which a conventional black medaka and a shurogayatsuri are performed in the same water tank. FIG. 6 is a diagram for explaining a breeding system using a pseudo water hyacinth for spawning medaka.

Explanation of symbols

10: Spawning bed 10a: Reticulated member 10b: Medaka passage hole 12: Floating member 14: Spawning bed for medaka 16: Connecting member

Claims (8)

A spawning bed for medaka including a spawning bed and a floating member for positioning the spawning bed below the water surface,
The spawning bed is composed of a net-like member, the opening diameter of the net-like member is set to a value within the range of 0.3 to 8 mm, and a medaka passage hole having an equivalent circle diameter of 10 to 50 mm is provided. Characteristic spawning bed for medaka. The spawning bed for medaka according to claim 1, wherein the net-like member is a strip-like shape, and the strip-like net-like member is rounded to form a loop to form a passage hole for the medaka. The spawning bed for medaka according to claim 1 or 2, wherein the number of passage holes of the medaka provided in the spawning bed is set to a value in the range of 2 to 6. The spawning bed for medaka according to any one of claims 1 to 3, wherein the color of the spawning bed is blue or black. The spawning bed for medaka according to any one of claims 1 to 4, wherein the floating member is made of expanded polystyrene. The egg-laying bed for medaka according to any one of claims 1 to 5, wherein the floating member has a plate shape. The spawning bed for medaka according to any one of claims 1 to 6, wherein the spawning bed and the floating member are connected via a connecting member. A spawning method for a medaka using a spawning bed for a medaka including a spawning bed and a floating member for positioning the spawning bed below the water surface,
The medaka which comprises the spawning bed with a mesh member, the mesh member has an opening diameter within a range of 0.3 to 8 mm, and a medaka passage hole having an equivalent circle diameter of 10 to 50 mm. Preparing a spawning bed for use;
Storing the medaka spawning bed and medaka in a water tank;
A step of growing medaka under a water temperature of 10 to 40 ° C .;
A method for spawning medaka, comprising: