JP2001161206A - Method for producing pinctada fucata martensii of japan growth - Google Patents

Abstract

PROBLEM TO BE SOLVED: To actualize Pinctada fucate martensii of Japan growth suitable for culture without extremely changing properties of Pinctada fucata martensii of Japan growth, fear of introduction of unknown infections diseases and blood of extraneous Pinctada fucata martensii in a method for producing Pinctada fucata martensii of pure Japan growth useful in pearl culture. SOLUTION: Pinctada fucata martensii of Japan growth is artificially hybridized to Pinctada fucata fucat living in the sea area of Keichoukan islands in Okinawa Prefecture. The seedling shell thus obtained can produce seedlings of Pinctada fucata martensii of Japan growth which avoid the appearance of inbreeding depression, has a stronger high temperature resistance than the case of intact Pinctada fucata martensii, resistance to infectious diseases and activity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing pure Japanese pearl oysters used for pearl culture.

[0002]

2. Description of the Related Art Pearl production has been steadily recovering since the recession of the early 1970's and has been growing steadily until around 1994. However, mortality has gradually increased at production sites, and the tendency of pearl quality to decline has increased. I went.

[0003] The main causes are deterioration of fishing grounds due to self-pollutation of mother pearls and pearl culture, poaching in pursuit of quality, contamination of fishing grounds due to fish culture, development of coastal residential land and development of resorts, domestic wastewater and industrial wastewater. Environmental destruction such as inadequate sewage treatment facilities is considered.

[0004] There are some reasons that farmers can deal with themselves,
Many of the preservation and improvement of the fishing ground environment is not a problem that can be solved only by the fish farmers themselves, but is a major issue in the future.

On the other hand, as a cause of the increase in mortality, strong selection for traits suitable for aquaculture is performed at the stage of larva culture, and at the same time, the same strong selection for seed shells used for artificial seedling is performed. Therefore, some have pointed out that inbreeding weakness has weakened the natural pearl oysters, but the exact cause has not been clarified so far.

[0006] As a result, mother mussels that are excellent in nacre secretion ability, are fast growing, and grow large in size are required in order to improve the survival rate and pearl orientation, and shorten the time from nucleus insertion to pearl collection. Was.

The southern part of the Bungo Channel is the largest pearl oyster natural fishing ground and suitable for cultivation of mother mussels. Most pearl oysters in Japan have been produced in this area.

[0008] Since about 1995, abnormal soft shells and scallop abnormal shellfish, which are considered to be infectious diseases, have been generated in a part of this sea area.
Mass deaths occurred in the same sea area in 1996, and from the following year, large numbers of deaths due to similar symptoms occurred on a nationwide scale, which has become a major problem that has shaken the industry.

Particularly in Ehime Prefecture, both the production value and the production amount have decreased to about 20% of the value before the mass mortality, and some areas are in a catastrophic situation. It has been pointed out that there is a high possibility that this infectious disease has entered with the introduction of foreign pearl oysters, and it is said that it may originate from the southern region based on the symptoms and the manner of damage.

[0010] Natural pearl oysters produced in Japan have suffered so much damage that they would be extinct if they were left as they were. On the other hand, Chinese pearl oysters show great resistance to this infection.

It is said that a certain amount of Chinese pearl oysters were brought into Japan around 1995, and the occurrence of infectious diseases, the time of introduction, and the sea area were in agreement.
It is pointed out that this is the main cause.

[0012] Thereafter, after the resistance of Chinese pearl oysters to this infectious disease was recognized, the result was that they were imported in large quantities. In addition, hybrid pearl oysters from China and Japanese pearl oysters (Hybrid-F1-) are also produced,
In the culture up to the pearl harvest, the survival rate was generally high and the nacre secretion ability was also excellent, so it was evaluated.

[0013] However, Chinese pearl oysters are not expected to have any specific species when used for breeding, and are expected to have many genetically localized types due to the vast land area.
In pearl culture, reproductive physiology is different,
Tailoring operation is difficult, nucleation work is unstable, and as a result, the quality of pearls is inferior and there are many problems that need to be solved, and both pearl oysters from China and pearl oysters from Japan will improve in the future Room is left.

As is well known, in China, pearl cultivation by the Chinese pearl oysters has been performed extensively, which has been a great wonder for the domestic pearl industry, but it is generally said that the quality is inferior at present. It has become. In this regard, it seems that the properties of Chinese pearl oysters are involved, as well as various aquaculture techniques.

At present, some regions are actively introducing Chinese pearl oysters to combat infectious diseases, while others are banning their introduction due to concerns that they may be the main cause of infectious diseases.

[0016] Because of the position that cultured pearls are unique to Japan, many industry people claim that they must protect Japanese pearls without introducing foreign pearl oysters. In addition, from the viewpoint of preservation of the Japanese pearl oyster population as a genetic resource and the epidemiological point of view, many people warn to introduce foreign pearl oysters and to use them for breeding, but it can be said that there is no concrete solution.

[0017]

[0009] In Japan, the moss B. niger lives from the Amami region to the Nansei Islands. The shellfish is smaller than the pearl oysters, but looks very similar, and is widely distributed from subtropical to tropical regions.

Pearl oysters (P. fucata mart)
ensii), as indicated by its scientific name, corresponds to a subspecies of P. fucata fucata, and therefore it is easy to imagine that P. falcipaen corresponds to the original species of pearl oyster or a species closer to the original species.

It has been heard that Beniko mussels were introduced to pearl farming in the past, but it is difficult to imagine them from the southwestern islands due to the background of the time, but compared to Pearl oysters, It is common opinion that is an unsuitable shellfish.

This was before the establishment of artificial seeding technology, which could not be evaluated as a genetic resource, was smaller in size overall than pearl oysters, had a smaller number of inhabitants, and had It is conceivable that the variability of the form was large and it was not possible to select a form suitable for aquaculture on a business scale.

When considering measures for breeding against the current infection and weakening of pearl oysters, it is of great interest that it is predicted that the moss will be close to the original species, and that once crossing, It can be expected that the pearl oysters will be able to regain their sturdiness, and since they live in subtropical waters, they could be expected to be resistant to infectious diseases.

However, as well as having different characteristics depending on the sea area where the pearl oysters inhabit, it is easily presumed that there is a local type depending on the sea area where the pearl oyster oysters inhabit. As a genetic resource, it is very important to determine where to place the Bivalve clam.

For example, there is a record that pearl oysters inhabiting the main island of Okinawa have been transferred to pearl oysters for pearl culture tests for a long time, and it is highly likely that the pearl oysters around the main island are hybridized. However, its value as a genetic resource seems to be low.

[0024] In addition, the number of living mussels themselves is extremely small compared to pearl oysters,
Since there is a great difference in morphology between individuals, it is important to cross where and what kind of traits of P. niger are crossed, and selection and breeding by itself can be said to be an inevitable task.

[0025] The present invention does not significantly change the properties of Japanese pearl oysters and does not cause any invasion of unknown infectious diseases.
An object of the present invention is to provide Japanese pearl oysters suitable for aquaculture without introducing foreign pearl oyster blood.

The production of pearls is being pursued all over the world, but the pearls made from Japanese pearl oysters, which are called Japanese pearls, are unique to Japan, and the pearl oyster, which is the mother shell holding the pearls, is purely Japanese. Being born is indispensable to maintaining the value of Japanese pearls as the only jewel that life creates, without damaging the image of pearls.

[0027]

The technical problem of the present invention is solved by the following means. A first aspect of the present invention is a method for producing Japanese pearl oysters, which comprises producing a seedling by artificially crossing a Japanese pearl oyster with a red mussel living in the waters of the Kerama Islands in Okinawa Prefecture.

As described above, the seedlings obtained by artificially crossing Japanese pearl oysters with the pearl oysters living in the waters of the Kerama Islands in Okinawa Prefecture can avoid the emergence of inbreeding weakness and have higher temperature tolerance than pearl oysters It is highly effective in breeding pearl oysters because it can produce Japanese pearl oyster seeds and seeds that are resistant to infectious diseases and have vitality.

It should be noted that the artificially crossed mussel of the female pearl oyster and the male of the pearl oyster is extremely resistant to high temperatures, but conversely, even in the case of the artificial bred of the male of the pearl oyster and the female of the pearl oyster, the pearl oysters Better than artificially bred shellfish.

A second aspect of the present invention is a method for producing Japanese pearl oysters, which further comprises artificially breeding the artificially bred shellfish obtained by the method of claim 1 with a Japanese pearl oyster to produce seedlings. .

As described above, the Japanese pearl oyster and the Japanese pearl oyster, which are obtained by artificially crossing the Japanese pearl oyster by the method according to claim 1 and the red mussel inhabiting the waters of the Kerama Islands in Okinawa Prefecture, are further artificially bred. According to the experimental results, the obtained seedlings also had a high survival rate in the sea area on the mainland of Japan and a high yield strength.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment will be described as to how the method for producing Japanese pearl oysters according to the present invention is actually embodied.

The Kerama Strait sandwiched between the Kerama Islands in Okinawa is an isolated strait where no pearl oysters have been introduced in the past, the Kuroshio that has passed through the main island of Okinawa has not flowed in, and Beniko mussels also live there. I have.

The Kerama Strait is famous as a diving mecca that records tens of meters of transparency. On the contrary, the marine phytoplankton and microbes such as bacteria, which are responsible for basic production, are extremely small. It is not suitable.

However, on the other hand, there are many types of marine organisms that live from the subtropics to the tropics, and it is also a sea area called Galapagos of the sea. The inventors of the present invention have been working on preservation and selective breeding as a useful genetic resource for breeding of pearl oysters in the Kerama Islands, about 10 years ago, from which the pearl oyster was collected.

[0036]

[Table 1] Inhabiting conditions of the genus Vulpes in Kerama waters
(October 1991)

[0037] Table 1 shows the collection status of the mussel family, which was naturally harvested on a large scale at Zamami Island in the Kerama Islands in 1991. Unlike the pearl oysters in Japan, unlike the pearl oysters in the mainland Japan, It will be appreciated that the number of distributions is small.
Even when diving on coral reefs and rocky reefs, I've never seen any natural clam of the squid.

After that, the larvae obtained from the artificial larvae were identified in Honshu, the larvae obtained by artificial seeding were collected, the difference in the reproductive cycle from the pearl oyster was confirmed, and the crossing test between the pearl oyster and the pearl oyster was conducted. Production of pearl oysters has been promoted.

[0039]

[Table 2] High water temperature tolerance test depending on the breeding water temperature (August 1996
Month)

Table 2 shows a high water temperature tolerance test in which the rate of transformation to D-type larvae reared for 32 hours from insemination in the control group (25 ° C.) and the high water temperature group (29 ° C.) was examined.

[0041] In the case where the eggs of the pearl oyster were crossed with the spermatozoa of the pearl oyster from Ehime, the normal development was continued in both cases.
Only over 5% of normal metamorphosis could be performed.

From this test, it was considered that the pearl oyster had higher temperature tolerance than the pearl oyster, suggesting a direction for promoting the breeding of pearl oysters.
It was also found that the artificially hybridized seedlings of the female pearl oyster and the male of the pearl oyster had better high-temperature tolerance than the artificially hybridized seedling of the pearl oysters.

[0043]

[Table 3] Survival rate survey in different sea areas (August 1998 to 1999)
(April)

Table 3 shows Beniko mussels x Beniko mussels artificial seedlings, Beniko mussels x pearl oysters, artificial seedlings, Chinese imported pearl oysters, and pearl oyster natural seedlings, respectively, in the Kerama area and Nanyo, Ehime prefecture. It is the result of rearing in the sea area.

Chinese pearl oysters are an epidemiological problem, and Japanese pearl oysters are not brought into the Kerama sea area because they cannot survive due to the environment. In Ehime, the line troglodytes outperformed the Chinese pearl oysters.

The environment in a subtropical sea area with little food is harsh for crossbred shells mixed with the blood of Japanese pearl oysters, such as the one shown in Ehime, although the survival rate is lower than that of those raised in the Nanyo region. It showed exactly the same tendency as the change, which proved that the Kerama area was very valuable as a seedfish selection fishing ground in terms of selecting stronger oysters.

[0047]

[Table 4] Survival rate survey of various seedling-producing shellfish (May 1999-1999)
October)

Table 4 shows artificial scallops and natural pearl oysters of Chinese pearl oyster ♀ × natural pearl oyster ♂, F1 (veneric oyster ♀ × pearl oyster ♀) ♀ × natural pearl oyster ベ, pearl pearl oyster ♀ × venerium pearl oyster ♀, respectively. These are the results of survivorship surveys that were reared offshore in the Nanyo area of Ehime Prefecture.

This year, the number of rainy days in the summer season when abnormal mortality occurs is large, and the seawater temperature has been relatively low. However, compared to natural pearl oysters, the survival rates of various seedling-producing shells are high, and it can be said that there is no significant difference in comparison with Chinese pearl oysters.

As described above, Japanese pearl oysters are in danger of becoming extinct due to environmental destruction and weakening of the cultivated sea area and infectious diseases. As a countermeasure, foreign pearl oysters are crossed as a breeding technique.

However, since the pearl oysters are put to practical use before the properties of the pearl oysters are confirmed, many problems have been pointed out in terms of epidemiology, protection of genetic resources, pearl culture techniques, and the like.

In addition, the progress of crossing of foreign pearl oysters has led to a possibility that since the invention of artificial cultivation of pearls, the trust of Japanese pearls, which have been recognized as jewels in the image of pure Japan, has been completely overturned.

However, according to the present invention, by crossing a pearl oyster with a domestic snail, which lives in Japan, the emergence of inbreeding weakness was avoided, and the mussel was robust and resistant to infectious diseases. It promotes the production of unmistakably Japanese pearl oysters, protects cultured pearl oysters, and maintains trust.

[0054]

According to the first aspect of the present invention, the seedlings of the Japanese pearl oyster artificially crossed with the Japanese pearl oyster living in the waters of the Kerama Islands in Okinawa are suitable for both female and male In both cases, it is possible to avoid the emergence of inbreeding weakness, and it is more resistant to high temperatures than pearl oysters, and it is also resistant to infectious diseases and can produce vigorous seeds of Japanese pearl oysters. It is extremely effective. As a result, the pearl pearl oyster cultured pearls can be protected and contribute greatly to maintaining trust.

According to a second aspect of the present invention, a Japanese pearl oyster and a Japanese pearl oyster obtained by artificially crossing a Japanese pearl oyster and a red mussel living in the waters of the Kerama Islands in Okinawa by the method of the first aspect are used. Furthermore, it was revealed that the seedlings obtained by artificial crossing also had a high survival rate in the sea area on the mainland Japan and a high yield strength.

Claims (2)

[Claims] 1. A Japanese pearl oyster (Pinctada)
fucata martensii and Pinctada inhabiting the waters of the Kerama Islands in Okinawa Prefecture
A method for producing Japanese pearl oysters, which comprises producing seedlings and shellfishes by artificially crossing Fucata fucata). 2. A method for producing Japanese pearl oysters, which further comprises artificially breeding the artificially bred mussels obtained by the method of claim 1 and Japanese pearl oysters to produce seedlings.