JPH07308138A - Medium for culturing lugworm - Google Patents

Abstract

PURPOSE:To obtain the lightweight, aseptic and clean medium for culturing lugworms, comprising a specific granular polymer, substantially not containing a water-soluble compound, having the maximum particle diameter of <= a prescribed value, capable of being repeatedly used, improving the raising yield of the lugworms and the saving of labor, and capable of being replaced with natural sand. CONSTITUTION:This medium for culturing the lugworms comprises a melt- moldable granular polymer having a true specific gravity, such as polyethylene terephthalate, PS or polymethyl methacrylate, does not contain a water-soluble compound such as a monomer or plasticizer contained in nylon-6 or soft polyvinyl chloride, and has the maximum granular diameter of <=30mm, preferably <=3mm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a culture medium for cultivated moss. More specifically, the present invention relates to an artificial medium for cultivating moss, which is suitable for culturing moss, and which can replace natural sand.

[0002]

2. Description of the Related Art Conventional sand culture media include sea sand,
Natural sand such as river sand has been used. However, natural sand cannot be expected to have a stable supply in the future because its collection is being restricted in order to prevent natural destruction, environmental destruction and landscape destruction. Further, since sand has a large specific gravity, it requires a great deal of labor for collection and transportation, and the price tends to increase more and more.

[0003] In addition, it is necessary that the culture medium for cultivated sesame is free of bacteria and chemicals. However, natural sand is likely to adhere to effluents of moss and uneaten food, so that even twice a day. Even if the seawater was replaced, it was necessary to replace the total sand once every six months to keep it clean. In addition, this total replacement of sand requires extremely heavy labor because it is necessary to separate the sand containing slag with a sieve.

Further, there is also a problem that the pearl oysters cultivated in natural sand have a dark color, have little redness, lack transparency and cannot obtain good quality.

On the other hand, among the polymer scraps generated during the production of fibers, films, etc., those which are acceptable in terms of quality may be depolymerized and reused as a part of the raw material, but the coloring is remarkable, and It is the current situation that polymer scraps that contain foreign substances and that are difficult to depolymerize are incinerated as industrial wastes or buried in the ground, and effective use of resources was desired. .

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a lightweight, sterile, clean culture medium for cultivated sesame. Another object is to provide an effective use method of waste polymer waste.

[0007]

The present invention has the following constitution in order to solve the above problems. That is, the true specific gravity is 1.
It is a culture medium for aquaculture, which is composed of 0 or more melt-moldable granular polymer, contains substantially no water-soluble compound, and has a maximum particle size of 30 mm or less.

The present invention will be specifically described below.

That is, as a raw material for the granular polymer that constitutes the culture medium for cultivated pearl oyster of the present invention, a polymer capable of being melt-molded is used in order to effectively utilize the polymer scraps generated during the production of fibers and films. Polymers such as polyethylene terephthalate, polybutylene terephthalate, polystyrene, polymethyl methacrylate, hard vinyl chloride and ABS can be exemplified.

It is necessary that the culture medium for cultivated pearl oyster of the present invention contains substantially no water-soluble compound. When a water-soluble compound such as a monomer or a plasticizer is contained, it adversely affects the growth of moss and deteriorates the quality of wastewater.
In the present invention, the phrase "substantially free of water-soluble compound" means that the content of the water-soluble compound is 50 ppm or less.

From this point of view, nylon 6 and nylon 6
Polymers containing a large amount of water-soluble compounds such as monomers and plasticizers such as 6 and soft vinyl chloride are not suitable for the material of the present invention.

Regarding the color of these polymers, a light color or white color is preferable from the viewpoint that it is easy to make the color tone of the cultivated oysters red and transparent and of high quality.

In order to make the above-mentioned polymer into a granular material, a method of pulverizing a raw material polymer having an arbitrary shape such as a lump by a known pulverizing means, or forming it into a granular form by a known forming means can be employed. When crushing polymer waste,
The shape and size of the granular polymer can be adjusted by appropriately selecting the type of polymer and the pulverization conditions (particularly the number of rotations).

The true specific gravity of the granular polymer used in the present invention is 1.0 or more. If the true specific gravity is less than 1.0, it tends to float in the water, and it becomes impossible for hunks to be hidden and hidden.

In the present invention, the maximum particle size of the granular polymer is 30 mm or less. When the maximum particle size exceeds 30 mm, there is a problem that the water retention property is lowered.

To obtain polymer granules having a maximum particle size of 30 mm, for example, after crushing the polymer waste as described above, 3
It suffices to apply it to a sieve having an opening of 0 mm. Further, in order to obtain a polymer particle having a maximum particle size of 3 mm, for example, the polymer waste may be crushed as described above and then passed through a sieve having an opening of 3 mm.

[0017]

EXAMPLES The present invention will be specifically described below with reference to examples.

Example 1 and Comparative Example 1 Polyester polymer scrap was used as a raw material polymer, and a powdered crusher 45-600 was used.
After crushing with a No. 2 type (manufactured by Someya Kogyo Co., Ltd.), a polymer granule having a maximum particle size of 3 mm or less including powder was produced with a sieve having an opening of 3 mm.

The true specific gravity of the obtained granules was 1.38, and the density (apparent specific gravity) of the medium for cultivating cultivated pearl oysters was in the range of 0.6 to 0.7 g / cm ³ .

In a vinyl house, one box is 200c wide
We made a continuous 32 squares of aquaculture farm made of concrete with a height of 200 cm divided by m and a length of 300 cm. The culture medium for cultivated sea bream was spread to a height of 10 cm in this culture box and filled with seawater pumped up to a height of 15 cm. At this time, since the medium contained bubbles, it was submerged in seawater sufficiently.

Next, about 3000 larvae of Gokai were scattered evenly in each box. Seawater was replaced in the culture box twice a day, and fish meal was sprinkled on the surface of the water. I became an adult after 4 months. The growth yield was as good as 85%. Also,
The color of the obtained pearl oyster had a reddish color and was of good quality with transparency.

For shipment, the aquaculture medium was sifted together with the aquaculture medium in order to remove the moss. The moss was left on the sieve, the medium was dropped down and returned to another culture with a stream of water. This operation has significantly reduced the work compared with the case of natural sand.

As Comparative Example 1, natural sand thoroughly washed with tap water was used. The density of natural sand was about 2 g / cm ³ . A sesame seed was cultivated in exactly the same manner as in Example 1 except that this natural sand was spread to a height of 10 cm. Growth yield is 75%
Met. Also, the obtained Gokai has a dark color,
There was little redness, lack of transparency, and the quality was slightly inferior to the examples.

In this case, it was necessary to replace the sand once a half year to keep it clean. In addition, this total replacement of sand requires extremely heavy labor because it is necessary to separate the sand containing slag with a sieve. Sorting for shipping was also extremely hard labor.

(Example 2, Comparative Example 2) When the medium used in Example 1 and Comparative Example 1 was repeatedly used 4 times, in the case of Example, there was almost no change in the growth yield and the first time. 8
It was 5%, the second time 83%, the third time 84%, and the fourth time 81%.

On the other hand, in the case of the comparative example, the growth yield is 75% for the first time, 70% for the second time, 40% for the third time, and 10% for the fourth time.
Therefore, the growth yield after the third time was significantly reduced. It seems that it is extremely difficult to keep the natural sand clean.

[0027]

EFFECTS OF THE INVENTION The culture medium for cultivated pearl oyster of the present invention has the following effects.

(1) Since it is a lightweight and sterile clean medium, the growth yield is good, and the growth yield does not decrease even after repeated use. It is possible to significantly reduce the amount of labor during sorting work such as harvesting. In addition, the quality of the obtained kaikai is also good.

(2) Polymer scraps treated as industrial waste can be used as a raw material polymer, which is useful from the viewpoint of effective utilization of resources.

Claims (2)

[Claims] 1. A melt-moldable granular polymer having a true specific gravity of 1.0 or more, containing substantially no water-soluble compound,
A medium for cultivating kaikai, which has a maximum particle size of 30 mm or less. 2. The culture medium for cultivated moss, according to claim 1, which has a maximum particle size of 3 mm or less.