JP2008206437A - Method of culturing oyster and oyster - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a culturing method by which deliciousness of oysters is great and labor required for culturing can be reduced and to provide the oysters having great deliciousness. <P>SOLUTION: The method for culturing the oysters includes an artificial fertilization step I of mixing sperms of the oysters with ova thereof and carrying out fertilization, a fertilized egg tending step II of growing the fertilized eggs in an aquarium until the fertilized eggs become larvae, a seeding step III of making the larvae adhere to oyster powder and preparing seed oysters, a primary culturing step IV of growing the individual seed oysters into adult oysters in the aquarium and a secondary culturing step V of further growing the adult oysters in a culturing cage in the sea. Since the artificial fertilization step I, the fertilized egg tending step II, the seeding step III and the primary culturing step IV can be carried out in a land facility, the labor can be reduced without being affected by a weather accident. In the stage of submarine culturing for carrying out the secondary culturing, the growth of shells is suppressed. Thereby, nutrients ingested from the interior of the sea are directed only to the growth of the flesh. As a result, the oysters having high deliciousness are obtained. Since the one oyster is grown from each individual seed, dominant species are selected to thereby afford the large and delicious oysters. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an oyster culture method and an oyster. More specifically, the present invention relates to a method for cultivating bivalves such as true oysters, rock oysters, clams and so on, and oysters cultivated by the method.

Oyster is a general term for the bivalve of the lobster family that adheres to the reef with the left shell, but it often refers to oysters that are especially edible.
The characteristics of these oysters are as follows. Because of the attached life, the shape is not constant, and the shell shape is irregular. The left shell is larger and deeper, and the right shell is slightly small and does not swell much. There is a black ligament in the meshing of both shells, but there are no teeth or very weak. In the center of the soft body there is a large posterior shell muscle (shell), and the gills in the mantle are large. There are hermaphroditic but strong females and strong males, and the sex ratio is determined by the conditions at that time.
In the case of egg embryos such as lobsters, male and female ova and sperm are formed in the same gonad, but in egg types such as magaku, eggs and sperm are produced alternately.
The egg laying in water is an appropriate temperature of 22-25 ° C., and the egg laid in the water becomes a beliger larva, but enters an attached life around 20 days. The growth will be about 7cm in one year and about 60g in weight, and about 10cm and 140g in two years.

As a method for culturing oysters, a drooping culture method using squid has been used since the 1920s. The outline is as follows (Non-Patent Document 1).
From May to August when the sea temperature of the inner bay reaches 24-25 ° C, the larva swimming in the sea grows to about 0.4 mm and begins to settle on rocks. At this time, a collector (applicator) with oyster shells and scallop shells is put in the sea and the young shellfish are attached and seeded. The adhering juveniles grow quickly and become sesame grains in 4-5 days. This is a seed oyster. This is a raft droop culture, but with this method the seed oysters are always in the water and eat, so they grow faster than those on the rocks exposed at low tide. When seed oysters are drooped in spring, they can be harvested in winter. Seed oysters are mainly produced in Miyagi Prefecture, and aquaculture is prosperous in Hiroshima, Ariake Sea and Miyagi Prefectures.

By the way, in the conventional raft type drooping method, many oysters adhere to a collector (such as a wire with a length of several meters) suspended from the squid in the sea and grow. In addition, it will be cultured in the sea from the beginning to the end of the culture.
However, in this conventional example, oysters grow in a row, so that nutrients taken from the sea are dispersed and eaten by recessive oysters, and the dominant oysters do not have enough nutrition. In addition, there is a limit to umami because it is used for shell growth and only partially used for shell growth. In addition, aquaculture requires manual work, but since it is always carried out at sea, a great deal of labor is used, and the harvest may decrease due to the influence of weather and wind.

Heibonsha Encyclopedia Volume 3, page 90

  In view of the above circumstances, an object of the present invention is to provide an aquaculture method that has a high umami taste, can reduce the labor required for aquaculture, and can be harvested regardless of the weather. Moreover, it aims at providing the oyster with much taste.

The oyster culture method according to the first invention includes an artificial insemination process in which oyster sperm and an egg are mixed and fertilized, a fertilized egg breeding process in which the fertilized egg is grown in a water tank until it becomes a larva, and the larva is attached to the oyster powder. A seeding process for producing seed oysters, a primary culture process for growing individual seed oysters into adult oysters in an aquarium, and a secondary culture process for further growing the adult oysters in an aquaculture basket in the sea It is characterized by.
The oyster culture method of the second invention is characterized in that, in the first invention, the growth of an adult oyster shell is suppressed in the secondary culture step.
The oyster of the third invention is characterized in that individual adult oysters are grown from individual seed oysters by the culture method of claim 1.

According to the first invention, the artificial fertilization process, the fertilized egg breeding process, the seeding process, and the primary aquaculture process can be performed on land facilities, so that the labor can be reduced without being affected by weather changes.
According to the second invention, since the growth of shells is suppressed at the stage of submerged aquaculture, the nutrients ingested from the sea are directed only to the growth of shells, so that oysters with high taste are obtained.
According to the third invention, one oyster is cultivated from each species, so that a oyster with a large taste can be obtained by selecting a dominant species.

Next, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory diagram of the aquaculture method of the present invention.
The culture method of the present invention is characterized in that the artificial fertilization process I, the fertilized egg breeding process II, the seeding process III, and the primary culture process IV are performed on land facilities, and the secondary culture process V is performed on the sea.
Hereinafter, the culture method will be described in the order of steps.

(Artificial insemination process I)
It is a process of fertilizing oyster sperm and egg.
Sperm and ovum can be released by applying an electric shock or incision to a male and female mother shellfish in a water tank.
When the released sperm and egg are mixed in the same water tank, a part of them is fertilized and an egg is born.

(Fertilized egg childcare process II)
The fertilized egg obtained in the step I is grown in a water tank until it becomes a larva. Some of the fertilized eggs grow into larvae, but usually it takes several hours.

(Seeding process III)
It is a step of making seed oysters by attaching the larvae obtained in the above step to oyster powder. Oyster powder is obtained by previously pulverizing oyster shells.

(Primary aquaculture process IV)
It is a process of growing individual seed oysters into adult oysters in a water tank. The water temperature in the aquarium is kept at 21 ° C. to 27 ° C., and phytoplankton is fed as food. Usually, several weeks are required, and seed oysters grow to several millimeters during this period.

(Secondary aquaculture process V)
In this step, the adult oysters grown to some extent in the step IV are further grown in an aquaculture basket in the sea. After growing to a size of about 4 to 6 mm, which is suitable for nutrient intake by the sea in the sea, it moves to underwater culture. In this case, it puts into the cultivation cage | basket 1 shown in FIG. 2, and is suspended in the sea from the squid 2 grade | etc.,. The farmed basket 1 is made of a net, and when several tens to several hundreds of adult oysters 0 are put therein, the oysters 0 ingest the nutrients and grow in the sea. It will grow to be edible in about 10 months.

FIG. 3 shows the appearance of an oyster grown and edible, and the body m is wrapped in two shells s. By the way, the nutrients ingested during aquaculture in the sea are used for the growth of the body, but also for the growth of the shell s. Therefore, the shell s will increase in proportion if it is only naturally cultivated in the sea, and no nutrients can be obtained in the body m.
Therefore, the present invention is characterized in that the growth of the shell s is suppressed in the secondary culture step V. Specifically, the cultured basket 1 is sometimes lifted from the sea and exposed to sunlight, and the cultured basket 1 is shaken or vibrated on the squid or on the land, and the shell s is worn away by friction between oysters. Any method may be used as long as the shell s can be worn out.
When the shell s is worn out in this way, more nutrients are absorbed by the body m, and the nutrients are concentrated by sunlight, so that the body m becomes sufficiently large and the umami increases.

According to the above culture method, one oyster is cultivated from one seed (seed). Since the artificial fertilization process I, the fertilized egg breeding process II, the seeding process III, and the primary aquaculture process IV can be performed on land facilities, the labor can be reduced without being affected by weather changes.
Moreover, since the growth of shells is suppressed at the stage of underwater cultivation, the nutrients ingested from the sea are directed only to the growth of shells, so that oysters with high taste are obtained.
And in the process of growing one oyster from one species, a dominant species can be selected, and since there is no dispersion of nutrients to minor species, large oysters can be obtained.

It is explanatory drawing of the culture method of this invention. It is explanatory drawing of aquaculture. It is an external view of the body and shell of an oyster.

Explanation of symbols

1 Farming basket 2 Squid 0 Oyster

Claims (3)

An artificial insemination process in which oyster sperm and eggs are mixed and fertilized;
A fertilized egg childcare process in which a fertilized egg is grown in a water tank until it becomes a larva,
A seeding process of attaching seedlings to oyster powder to make seed oysters,
A primary aquaculture process for growing individual seed oysters into adult oysters in the aquarium,
A method for culturing oysters comprising a secondary culturing step for further growing the adult oyster in an underwater cultivated basket. 2. The method for culturing oysters according to claim 1, wherein growth of adult oyster shells is suppressed in the secondary culture step. An oyster characterized in that individual adult oysters are grown from individual seed oysters according to the culture method of claim 1.