JP2013141455A - Aquacultural method for corbicula - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aquacultural method capable of efficiently removing parasites in a process of growing spawn and D-type larvae of corbicula, and capable of stably culturing the corbicula.SOLUTION: The aquacultural method for corbicula uses the supernatant liquid of blue water containing phytoplankton, as the rearing water of the spawn or the D-type larvae released from a corbicula mother shellfish, which method comprises a washing step of washing the spawn or the D-type larvae to wash out the parasites by using a mesh cloth of ≥50 μm and ≤70 μm. The washing step comprises a step of spraying mist water to the spawn or the D-type larvae by using a sprayer. Thus, the parasites adhering to coil around on the mesh cloth and the parasites adhering on the spawn or the D-type larvae can be efficiently removed.

Description

  The present invention relates to a method for cultivating rainbow trout.

  In Japan, it is known that three kinds of rainbow trout, masashijimi, setashijimi and yamatoshijimi, live. Of these, swordfish are inhabiting freshwater bodies and inhabit brooks throughout the country. Setashijimi is an endemic species of Lake Biwa. On the other hand, Yamato Shijimi is a swordfish that lives in brackish lakes such as Lake Shinji and brackish waters in estuaries.

  Shijimi is widely used for food and is known to enhance liver function by the action of methionine, etc., and also has the effect of purifying muddy water, so it is important from the viewpoint of water quality and environmental conservation. Is recognized.

  However, Shijimi's production has been declining year by year. From 1965 to 1950, the annual output was 50,000 tons, compared to 17,000 tons in 2001, 13,000 tons in 2006, and 2008 It is about 0.98 million tons after 10,000 tons per year.

  Considering this situation, not only edible blemishes are decreasing, but the water purifying action of lice is not sufficiently functioning in nature. Therefore, it can be said that the water quality conservation of rivers and lakes by swordfish, which has been made natural in the past, has caused a serious problem in terms of environmental conservation that has not been adequately done in recent years.

  In order to solve such a problem, a technique for efficiently cultivating rainbow trout is necessary. An example of a technique for cultivating swordfish is described in Patent Document 1.

JP 2010-259421 A

  An important problem that cannot be avoided when cultivating rainbow trout efficiently is that parasites that parasitize eggs and D-type larvae released from the scallop mother shellfish and kill the eggs and D-type larvae. It exists. Shijimi's eggs and D-type larvae are minute creatures, so once the parasites are attached, the parasites grow in a short time, and the eggs and D-type larvae die. By that time, the number will be greatly reduced, and juvenile shellfish cannot be raised stably. Therefore, how to remove parasites in the growth process of eggs and D-type larvae is an important issue.

  The present invention has been made in consideration of such circumstances, and in the growth process of swordfish eggs and D-type larvae, parasites can be efficiently removed, and swordfish can be stably cultivated. The aim is to provide possible aquaculture methods.

  In order to solve the above-mentioned problems, the method for cultivating a rainbow trout according to the present invention uses a supernatant of blue water containing phytoplankton as a breeding water for eggs or D-type larvae released from the mother of rainbow trout. A culture method, characterized by having a washing step of washing the eggs or D-type larvae using a mesh cloth of 50 μm or more and 70 μm or less to wash away the parasites.

  By using the supernatant of blue water containing phytoplankton as breeding water, it is possible to suppress the parasites contained in the precipitate of blue water from adhering to the eggs of swordfish or D-type larvae. In addition, by washing the eggs or D-type larvae with a mesh cloth of 50 μm or more and 70 μm or less, the mesh cloth can function as a filter to wash away the parasites. And parasites can be separated.

  Since the maximum size of the parasite in the swordfish egg or D-type larvae is 50 μm, if the mesh cloth size is less than 50 μm, the parasites cannot pass through the mesh cloth, and the egg or D-type larvae And parasites cannot be separated. In addition, when the size of the mesh cloth exceeds 70 μm, among eggs or D-type larvae, small-sized ones can pass through the mesh cloth, and the number of eggs or D-type larvae that can be collected for aquaculture is reduced. , Productivity decreases.

  In the method for cultivating rainbow trout according to the present invention, it is preferable that the cleaning step includes a step of spraying mist-like water onto the egg or D-type larvae using a sprayer.

  Although many parasites can be separated by the mesh cloth, there are cases where parasites attached to the mesh cloth so as to be entangled, or parasites attached to the eggs or the D-type larvae may remain. Therefore, these parasites can be efficiently removed by spraying mist of water on the eggs or D-type larvae using a sprayer.

  ADVANTAGE OF THE INVENTION According to this invention, the cultivation method which can remove a parasite efficiently in the growth process of a swordfish egg and D type larvae, and can culture a swordfish stably is realizable.

Below, the culture method of the rainbow trout of this invention is demonstrated based on the embodiment.
This embodiment is an example of a rainbow trout, which is applied to the cultivation of a rainbow trout. Aquaculture methods can be applied.

  Collect the mussel mussel and wash the mussel with coarse salt. Thereby, the germs adhering to the shell of the mother shell can be removed. Then wash the mother shellfish with tap water or well water. Place the mother shellfish in a hot water-treated container, add boiled water, leave it for about an hour, and spit out mud and sand from the mother shellfish. Thereafter, if necessary, washing of the mother shell with coarse salt and washing of the mother shell with tap water or well water are repeated.

  Then, after immersing the mother shellfish in a serotonin solution for about 45 minutes, the mother shellfish is taken out and washed with boiling water, and the mother shellfish is stored in a container for egg laying. In this state, the supernatant liquid of blue water, which is water for breeding, is poured into the mother shellfish. Blue water means water that has turned green due to breeding of phytoplankton. Blue water is commonly used for breeding ranchus, and phytoplankton grow by feeding nitrogen compounds in ammonia, nitric acid, etc. present in the water from sewage such as ranchu feces, urine, and food waste. The clear water turns dark green. The reason for using the supernatant of the blue water is to prevent the parasite and other harmful insects from being contained in the precipitate of the blue water, and to prevent the parasite from adhering to the mother shell at this stage as much as possible. Blue water may contain zooplankton and green algae in addition to phytoplankton.

When egg release from the mother shellfish or release of the D-type larvae is confirmed, the mother shellfish is taken out and the eggs or D-type larvae are washed. The washing process of eggs or D-type larvae is performed by the following method.
In the case of D-type larvae, dust is removed using a 200 μm mesh cloth, and in the case of eggs, dust is removed using a 150 μm mesh cloth. Thereafter, the eggs or D-type larvae are washed using a mesh cloth of 50 μm or more and 80 μm or less, more preferably 50 μm or more and 70 μm or less, and the parasite is washed away. Since the parasite is smaller than the egg or D-type larva and has a maximum size of 50 μm, the egg or D-type larva and the parasite can be separated by using such a mesh cloth. Here, the dimension of the mesh cloth means the dimension of the opening of the mesh cloth, and the mesh cloth of 50 μm or more and 70 μm or less means that the size of the opening is 50 μm or more and 70 μm or less.

  Thereafter, mist-like water is sprayed on the eggs or D-type larvae on the mesh cloth using a sprayer. This makes it possible to remove parasites that cannot be removed only by filtration with a mesh cloth, such as parasites attached to the mesh cloth so as to be entangled with the mesh cloth or parasites attached to eggs or D-type larvae. Thereafter, the eggs or D-type larvae are transferred to a sterilized container, and the supernatant liquid of blue water is poured. Here too, by using the supernatant of the blue water, it is possible to suppress the parasites contained in the precipitate of the blue water from adhering to the swordfish eggs or D-type larvae.

  The condition of the eggs or D-type larvae is observed every day, and when the occurrence of parasites is confirmed, the washing process described above is performed to remove the parasites. A comparison between the test plot where the washing process was performed and the test plot where the washing process was not performed showed that eggs or D-type larvae grew smoothly in the test plot where the washing process was performed. In the test area where the process was not carried out, most eggs or D-type larvae died due to the effects of parasites. This fact demonstrated that the above-described washing step was essential for good growth of eggs or D-type larvae, eliminating the adverse effects of parasites. The supernate solution of breeding water is replaced little by little every day to replenish phytoplankton as a feed.

  D-type larvae become larvae in about 2 to 3 months. In addition, eggs become D-type larvae in about 72 hours after egg release, and then become larvae in about 2 to 3 months. By introducing the larvae thus obtained into a culture pond and growing them until they become large individuals, stable production of rainbow trout becomes possible. In nature, eggs and D-type larvae are not only killed by parasites, but also feed on other organisms, so the number of eggs and D-type larvae is greatly reduced before they become juveniles. Usually, when the culture method of the present invention is used, growth at the stage of eggs or D-type larvae is performed smoothly, so that stable supply of rainbow trout is possible.

  INDUSTRIAL APPLICABILITY The present invention can be used as an aquaculture method that can efficiently remove parasites and can stably cultivate swordfish during the growth process of swordfish eggs and D-type larvae. Therefore, not only can the swordfish obtained by aquaculture be used for food, but it can also be used as a means for preserving the water quality of rivers and lakes using the water purification effect of the swordfish.

Claims (2)

  A method for cultivating swordfish using a supernatant of blue water containing phytoplankton as a breeding water for eggs or D-type larvae released from mothers of swordfish, using a mesh cloth of 50 μm or more and 70 μm or less, A method for cultivating rainbow trout, comprising a washing step of washing eggs or D-type larvae and washing away parasites.   The method for cultivating rainbow trout according to claim 1, wherein the washing step includes a step of spraying mist-like water onto the egg or D-type larvae using a sprayer.