KR20220028911A - The farming method of Catadromous fish applied to the circulation filtration and the medium development of elver using seawater - Google Patents

Abstract

The present invention relates to a farming method of catadromous fish applied to circulation filtration and the medium development of a small eel using seawater, and more specifically, to in particular, a farming method of an eel, such as the catadromous fish, which includes the farming of intermediate seeds in low-salt breeding water mixed with seawater and freshwater so as to improve the quality and color of the eels cultured in freshwater, and to improve the quality and coloration of eels cultured in freshwater.

Description

The farming method of Catadromous fish applied to the circulation filtration and the medium development of elver using seawater

The present invention relates to a method for culturing descent fish to which circulation filtration using seawater and intermediate breeding of eels is applied. It relates to a method for cultivating descent fish, especially eels, comprising the cultivation of intermediate seeds in low-salt breeding water mixed with high-salt breeding water and the cultivation of adult fish using the circulation filtration method in high-salt breeding water.

In general, eels and salmon are fish species that go back and forth between freshwater and seawater. Like eels, fish that spawn in the sea to hatch, come up to the river to grow, and then go back down to the sea are called descent fish. A fish with a habit of migrating to seawater to grow and then return to the place of birth for spawning is called an anadromous fish.

Both of these divergent fish and anadromous fish use their osmotic pressure control ability to go back and forth between freshwater and seawater, and aquaculture is also possible using this.

Seawater fish have a lower salinity than environmental water, so to prevent physiological dehydration, seawater is introduced into the body to absorb moisture from the intestines. It is discharged to the outside through the body, and urine is discharged in a very small amount to maintain body moisture.

In addition, when the salt cells are activated in the gill tissue, growth hormone (G.H) is highly expressed, and the expressed growth hormone is involved in the growth, metabolism, reproduction, etc. of organisms. The level of expression of these growth hormones varies depending on the weight of the fish, and it is known that it takes up to 30 days to express.

Among eels, Anguilla japonica, an eel from the Far East, is also known to inhabit seawater and freshwater, or in brackish areas where seawater and freshwater meet, using the function of osmotic pressure control in the body.

In addition, Far East eels account for more than 90% of domestic cultured eels, and most of them are cultured using groundwater or dry water (surface water) using static and circulation filtration methods. More than 90% of them are concentrated on the farm, and the annual aquaculture production is about 10,000 to 15,000 tons.

As such, since most eel farming from the Far East is carried out in freshwater, there are problems with the unique smell of freshwater fish, soft meat, and high cholesterol. In addition, the quality of the adult fish supplied to consumers is not uniformly provided because there are differences in taste, fishy smell, and smell of adult fish depending on the environment of the farm.

In order to solve the problems in freshwater aquaculture, descent fish farming using seawater was attempted.

Korean Patent Registration No. 10-1489660 (registration on January 29, 2015; hereinafter referred to as 'Prior Document 1') suggests a method of culturing descentic fish through a circulating filtration method and a stepwise acclimatization of seawater. The preceding document 1 suggested a method of cultivating fry as adults in low-salt breeding water through the fry breeding stage, and improving the meat quality and shipping them through the process of acclimatization to seawater under no-feed conditions before shipment. Although the prior document 1 is low salt, the salinity of the breeding water is 4 to 6 permil, so the mortality rate of fry is high, and the meat quality is improved by the implementation of the breeding process, but there is a problem in that economic efficiency is lowered due to weight loss after breeding.

Korean Patent Registration No. 10-1609906 (registered on March 31, 2016; hereinafter referred to as 'Prior Document 2') presented a method for inducing maturation of freshwater eels. In the preceding document 2, the sex maturation hormone input process is periodically executed after acclimatizing the selected parent fish in seawater as a culture method to secure high-quality fertilized eggs from the parent fish (the mother for spawning). It can be seen that Prior Document 2 is a breeding method for parent fish to obtain a large amount of fertilized eggs, which is different from general edible culture, and is different from the purpose of removing fertilized eggs in seawater. In addition, since the breeding method from fry to adult fish is the same as that of general freshwater aquaculture, problems such as fishy smell and fishy smell are still inherent. In addition, the seawater brine method applied in Prior Document 2 is a method of increasing the salinity step by step, but since it forms a long stress period for eels, there is a problem in that the survival rate due to long-term stress decreases when applied to fry with a low weight.

Korean Patent Registration No. 10-1489660 (registration on January 29, 2015): Method for cultivating divergent fish through circulation filtration method and step-by-step seawater purification Korean Patent Registration No. 10-1609906 (Registered on March 31, 2016): A method for inducing maturation of freshwater eels

In order to solve the problems of the prior art as described above, the method for cultivating descent fish of the present invention,

This is for cultivating descent fish, especially eels, in seawater, and the purpose of this is to provide a culture method that can overcome the disadvantages of freshwater breeding by cultivating it in seawater.

In particular, in order to shorten the period of stress caused by salinity changes, breeding is carried out by direct input to seawater. To provide a format that makes it possible.

In order to solve the above problems, the method for cultivating descent fish of the present invention,

In a method for aquaculture of descent fish using seawater, saltwater and freshwater are mixed to produce 0.2-2.0 psu of low-salt breeding water, and fry are acclimatized to the prepared low-salt breeding water to produce intermediate seeds through mouthwash. seed production process; It includes; a process of cultivating adult fish by producing 10-33 psu of high-salt breeding water using seawater, and cultivating intermediate seeds in the prepared high-salt breeding water.

The intermediate seed production process includes a low-salt breeding water production step of mixing seawater and fresh water to produce 0.2-2.0 psu of low-salt breeding water; A stocking environment creation step of storing the prepared breeding water in a low-salt water tank, but creating a stocking environment for fry generating a water flow while changing the low-salt breeding water at a rate of 2-3 ton/h; stocking the fry caught in the brackish pond in the low-salt water tank where the stocking environment is created, and acclimatizing the fry without feeding; A mouthwash step of supplying mouthwash feed to a low-salt water tank to increase adaptability to feed; It can be made including; the intermediate seed production step of cultivating the medium seed size through feed feeding when the mouth-to-mouth is finished.

In addition, in the intermediate seed production process, in the stocking environment creation step and the frying step, the low-salt breeding water temperature is set to 15~20℃ so that the stocking is performed and then acclimatized for 36~72 hours; In the mouthing step, the temperature of the low-salt breeding water is raised by 1°C every 3 to 5 hours to make it 28-31°C, so that the mouthpiece can be achieved.

In addition, the adult fish breeding process, using seawater, a preparation step of high-salt breeding water with a salinity of 10 to 33 psu; A high salt breeding water quality management step of storing the prepared high salt breeding water in a high salt water tank, but managing the high salt breeding water through a circulation filtration means; Intermediate seed acclimatization step of transferring and stocking the intermediate seeds produced in the intermediate seed production process; It may include; an adult fish breeding step of nurturing an adult fish by supplying feed.

In addition, in the intermediate seed acclimatization step of the adult fish breeding process, the medium seed stocking is performed by setting the high salt stocking water temperature to 15-25 ° C. Then, the high salt stocking water temperature is raised by 1 ° C. It can be acclimatized for 36 to 72 hours without feeding.

In addition, the circulation filtration means circulates a part of the high salt breeding water in the high salt water tank by a pump, and performs a filter filtration step by a physical filtration filter, a biological filtration step by a biological filtration tank, and a UV sterilization step by UV irradiation. can make it happen

In addition, it is preferable that the dissolved oxygen in the low-salt breeding water and the high-salt breeding water be maintained at 7-12 mg/L by an oxygen supply means.

In addition, the divergent fish of the present invention is an eel, and among eels, it may be any one of japonica (Anguilla japonica), bicola (Anguilla Bicolor), and malmorata (Anguilla marmorata). However, other than the above eels, it is possible to apply descent fish as a whole culture method.

The method for cultivating descent fish of the present invention by the above solution means,

Until the survival rate increases in response to sudden salinity changes, the fry are bred with medium seeds in low-salt breeding water. This can reduce the weight and prevent economic loss.

In addition, since adult eels are grown in seawater, the taste is improved by significantly reducing the smell and fishy smell of eels grown in freshwater. This made it possible to provide a way to promote consumption.

1 is a flowchart illustrating a method for cultivating descent fish according to a preferred embodiment of the present invention.
Figure 2 is a block diagram showing an adult fish breeding system including a high salt water tank for performing the adult fish breeding process according to the present invention;
3 is a graph showing the mortality rate during breeding of eels according to the salinity of breeding water.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Since the present invention can have various changes and can have various forms, specific embodiments are illustrated in the drawings and the present invention will be described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention. In describing each figure, like reference numerals have been used for like elements. In the accompanying drawings, the dimensions of the structures are enlarged or reduced than the actual size for clarity of the present invention.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as "comprises", "comprises" or "have" are intended to designate that a feature, number, step, operation, component, or combination thereof described in the specification exists, and is one or the It should be understood that the existence or addition of the above other features or numbers, steps, operations, components or combinations thereof is not precluded in advance.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those generally used and defined in the dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and are not to be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. .

1 is a flowchart illustrating a method for cultivating descent fish according to a preferred embodiment of the present invention.

First, in the general freshwater eel farming process, the stocking method of stocking eels is to acclimatize eels caught in brackish water to freshwater and then supply them to the farm. For transporting the eels, a plastic bag for transporting living organisms is usually used. In addition, oxygen is supplied to the water used for brooding, and the entrance of the plastic pack for animal transport is sealed with a rubber band or a band, and then transferred to the farm in an insulated transport box such as a styrofoam box to prevent death during transport. there is.

In this method, not only domestic thread eels, but also imported thread eels are packaged in a similar way to the above, transported by air, and then supplied to farms.

The eels supplied to general aquaculture farms are bred by stocking groundwater or surface water in a tank heated to 15°C-20°C using a heat pump or boiler.

The method for cultivating descent fish of the present invention includes a process for producing intermediate seeds by acclimatizing eels captured and transported from brackish water areas to low-salt breeding water, not groundwater or surface water, and using the produced intermediate seeds in high-salt breeding water. This is done through the process of nurturing an adult language by acclimatizing it to an adult language.

The intermediate seed production process is a process of producing a low-salt breeding water of 0.2 to 2.0 psu by mixing seawater and fresh water, and producing an intermediate seed through mouthing by acclimatizing the fry to the prepared low-salt breeding water;

The adult fish breeding process is a process of producing 10-33 psu high-salt breeding water using seawater, and cultivating adult fish by acclimatizing intermediate seeds to the prepared high-salt breeding water.

In the intermediate seed production process of the present invention, a low-salt breeding water production step, a stocking environment creation step, a young fry step, a mouth attaching step, and an intermediate seed production step are performed.

The low-salt breeding water production step is a step of preparing and supplying low-salt breeding water having a salinity of 0.2 to 2.0 psu by mixing seawater and fresh water as breeding water supplied to a low-salt water tank for cultivating fry as intermediate seeds. In order to increase the survival rate, the concentration of breeding water in which accretion is made is 0.2, because the survival rate of eels caught in brackish water is again put into breeding water with a salinity of 13±10 psu. This is the stage of preparation in low-salt broth of ~2.0 psu.

Next, the step of creating a stocking environment is carried out. In this step, a water wheel is installed in the low-salt water tank that stores the low-salt breeding water, and the water flow is generated inside to create an environment that rises up the water.

In addition, in order to increase the survival rate of the fry, an exchange operation is performed in which the low-salt breeding water is replaced by a certain amount in the low-salt water tank. The breeding water exchange is to rapidly discharge carbon dioxide or ammonia contained in a large amount of water discharged from the fry in the breeding process to lower the residual concentration to increase the survival rate of the fry. The exchange of the breeding water is made at 2-3 ton/h to keep the concentration of carbon dioxide or ammonia low. Of course, it is possible to increase the exchange rate per hour, but this increases the water quality management cost, but the effect of increasing the survival rate of fry is insignificant, so it is economical to exchange it in the above.

When the stocking environment of the low-salt water tank is created, the frying stage is performed. In this step, the fry caught in the brackish pond are stocked in the low-salt water tank to adapt the fry to the low-salt breeding water. Here, it is preferable that the temperature of the low-salt breeding water is formed in the range of 15 to 20° C. to be similar to the temperature of the plastic pack captured in the brackish region, so that the temperature adjustment in the stocking process is easily achieved. That is, the low-salt water tank is preferably set to a temperature similar to the temperature of the transportation water in the container for transporting the fry through the stocking environment creation step to create a frying environment.

In addition, after stocking the fry in the low-salinity tank, adaptation is made without feeding for about 36 to 72 hours.

In the process of acclimatization of the fry to the low-salt breeding water, salt cells are activated in the fry, and a large amount of water is discharged to the outside during the salt cell activation process. At this time, the discharged water contains carbon dioxide or ammonia, and the concentration can be increased to a lethal dose in the low-salt breeding water. can be raised

In addition, when carbon dioxide or ammonia increases above the set concentration by additionally installing a measurement sensor, the exchange amount of saltwater can be temporarily increased to keep carbon dioxide and ammonia below an appropriate level in the low-salt water tank.

Next, the mouth-to-mouth step is performed. The mouth-to-mouth stage is a step to generate adaptability to feed by supplying mouth-watering feed to the low-salt water tank when frying is completed.

In the mouthing step, the salinity of the low-salt breeding water is maintained, the dissolved oxygen amount is maintained at 7~10mg/L using an oxygen supply means, the temperature of the low-salt breeding water is formed at 28~31℃, and then the make the supply happen. At this time, it is desirable to raise the water temperature by 1°C every 3 to 5 hours to minimize the stress on the fry according to the sudden change in water temperature.

When the mouthing is completed, the intermediate seed production step is performed. The intermediate seed production is a step of cultivating an individual weight of 10 to 30 g by performing feed feeding to the fry that have finished nibbling.

When the individual weight is set to 10 g or more, the expression of growth hormone according to the change in salinity occurs rapidly and the growth rate is increased only when the individual weight is 10 g or more. because it becomes

In addition, the feed is fed twice a day at 12 hour intervals in the case of eels, which are fry; After passing the white porcelain and black porcelain state, compound feed (dough feed) or EP feed (floating feed) can be fed. At this time, the compound feed (kneaded feed) is fed twice a day at 12 hour intervals, and in the case of EP feed, the total amount of feed for the day is divided by time, or fed at 2 to 4 hour intervals. it is preferable

On the other hand, after the fry are cultivated as intermediate seeds, the adult fish breeding process is performed by transferring and stocking them to a high-salt water tank.

The adult fish cultivation process consists of a high-salt stocking water preparation step, a high-salt breeding water water quality management step, an intermediate seed acclimatization step, and an adult fish breeding step.

The high-salt stocking water preparation step is prepared in seawater with a salinity of 10 to 33 psu.

The high salt breeding water quality management step is a step of storing the prepared high salt breeding water by putting it in a high salt water tank, and managing the water quality through a circulation filtration means. As the circulation filtration means, various known filtration means may be applied to achieve water quality management.

Next, the intermediate seed acclimatization step is performed.

The intermediate seeds are transferred from the low salt water tank to the high salt water tank by the transfer container, and the high salt stocking water in the high salt water tank before stocking is set at 15-25 ° C. At this time, even in the low salt water tank, the temperature is lowered to 15-25 ° C., and then placed in a transfer container to move to the high salt water tank. Here, the temperature is lowered to be transported so that the intermediate seeds of the eels are kept in a tense state so that they can easily respond to changes from the outside.

The transfer container containing the intermediate seeds is immersed in a high-salt water tank, and the temperature acclimatization is made for about 20 minutes to 1 hour, and then stocking is made, thereby reducing the stress caused by the temperature change.

In addition, in the intermediate seed acclimatization stage, the temperature of the high-salinity breeding water in the high-salt water tank where the acclimatization is completed is raised by 1°C every 3 to 5 hours to 28-31°C, and it is allowed to acclimatize without feeding for 36-72 hours.

As such, it is cultivated as an intermediate seed in low-salt breeding water, and the ability to adapt to an environment in which salinity is changed is increased, so that even if it is injected at once in high-salt breeding water, a high survival rate is provided. This is because the stress time due to shortening the total salinity change time is shorter than the method of increasing the salinity step by step.

When the acclimatization stage is completed, the adult fish development stage is performed. In this stage, feeding is carried out in seawater, high-salt breeding water, and 10~30g intermediate seeds are nurtured into 300g or more individuals.

In addition, since they are nurtured as adult fish in seawater, they can be shipped immediately, thereby preventing weight loss due to the existing livestock raising process.

2 is a block diagram illustrating an adult fish rearing system including a high salt water tank for performing an adult fish rearing process according to the present invention.

The high salt water tank 20 has one so that the oxygen supply means 40 and the circulation filtration means 30 are coupled, or as shown, a plurality of high salt water tanks 20 are provided and oxygen is supplied to each of the high salt water tanks. It may be provided in the form of having a means 40 and a circulation filtration means (30). In the form having the plurality of high salt water tanks, some devices may be integrated and used.

The adult fish breeding system 10 of the present invention stores high salt breeding water in the high salt water tank 20 and stocks intermediate seeds to cultivate adult fish. The high-salt water tank 20 dissolves the high-concentration oxygen provided from the oxygen supply unit 41 by the oxygen supply means 40 installed on one side in the high-salt breeding water in the oxygen dissolver 42, thereby reducing the dissolved oxygen to 7-10 mg/L. keep in the range of In addition, a circulation filtration means 30 is installed in the high salt water tank 20 so that ammonia, nitrite, nitrate, etc. are decomposed in the biological filtration tank 32 and sterilized through the UV sterilizer 33 so that the water quality is managed. do.

That is, the high salt breeding water stored in the high salt water tank 20 is supplied to the filtration filter 31 by the pump (P) pressure to filter out feed residues, excrement, foreign substances, etc. of 40 to 100 μm or more contained in the high salt breeding water. The high-salt breeding water that has passed through the filtration filter 31 is introduced into the biological filtration tank 32, and reacts with the filter medium in the biological filtration tank to remove ammonia, nitrite, nitrate, and the like. The high-salt breeding water that has passed through the biological filter tank is sterilized by UV light while passing through the UV sterilizer 33, and then circulated to be supplied back to the high-salt water tank. As the filtration filter 31, various air filtration filters such as drum screen, mesh screen, etc. may act according to the installation environment.

As described above, if the water quality is managed by providing the circulation filtration means 30 and the oxygen supply means 40, high-density aquaculture is possible, thereby increasing production compared to limited facilities.

In addition, since it is grown as an adult fish in seawater, it is possible to significantly remove the smell of sea persimmons rather than a freshwater culture method, and it is possible to provide a solid meat quality and a low cholesterol eel.

In addition, the adult fish breeding system 10 installs a heat pump or a heat exchanger in the discharge line of the system to recover the heat of the discharged breeding water and use it as a heat source to heat the breeding water to reduce the cost of heating the breeding water. can do it

Example

Example 1 Intermediate seed production of eels from Far East according to salinity change

In 9 round tanks with a diameter of 2 m, the salinity of the breeding water was set in the range of 0.1 to 30 (0.1, 0.5, 1.0, 2.0, 3.0, 5.0, 10.0, 15.0, 30.0) psu, and inputted to each tank. eels; Anguilla japonica) were stocked at 2,000 each.

The water temperature was set at 18°C, and the plastic bag containing the eels was immersed in the water tank for about 1 hour, and after the temperature was acclimatized, the eels were released into the tank.

Dissolved oxygen in the breeding water was maintained at 7-10 mg/L through an oxygen supply means, and a water flow was formed through a water wheel.

The breeding water in the tank was raised to a temperature of 1°C every 5 hours to finally reach 30°C.

After 48 hours, oral feed was fed twice a day, at 12 hour intervals, and the seeds were bred for 2 months to produce intermediate seeds.

The dead individuals were checked by salinity of each tank and shown in FIG. 3 below.

It was confirmed that the mortality rate was similar to around 2.00% from salinity 0.1psu breeding water corresponding to freshwater to 3.0psu breeding water, and from breeding water with a salinity of 5.0psu or higher, the mortality rate increased rapidly.

Therefore, it can be seen that in the case of eels, productivity is lowered due to a high mortality rate at a breeding water salinity of 3.0 psu or higher, and thus it is difficult to grow fry by directly injecting them into seawater.

Example 2 Production of intermediate seeds of Far East eels at low salinity

Each tank was equipped with two concrete tanks of 10m horizontally and vertically.

One tank stored fresh water, and the other tank stored low-salinity breeding water with a salinity of 0.2psu to 0.5psu.

A total of 300,000 eels were stocked, 150,000 each in each tank.

The water temperature at the time of stocking was 18 ℃, and after soaking the plastic pack containing the eels in the water tank for about 1 hour, the eels were released in the water tank, the water wheel was rotated at 60 rpm, and the oxygen concentration was adjusted to 7mg/liter~10mg/liter through the oxygen supply means.

After 48 hours, the oral feed was fed twice a day, at 12 hour intervals, and bred for 2 months to produce intermediate seeds.

Example 3 Measurement of mortality during seawater breeding according to low-salt breeding period

Six round tanks with a diameter of 2 m contained breeding water with a salinity of 15 psu, the salinity of seawater.

The intermediate seeds fed in the low-salt breeding water of Example 2 were stocked in each tank by weight, but those bred at 2g, 5g, 10g, 15g, 30g, and 50g of each individual weight were stocked.

In each tank, the water temperature at the time of stocking was set at 20℃, and the plastic bag containing the intermediate seeds was immersed in the tank for about 1 hour, and the intermediate seeds were released into the tank after the temperature was acclimatized.

Dissolved oxygen in the breeding water was maintained at 7-10 mg/L through an oxygen supply means, and a water flow was formed through a water wheel. The breeding water in the tank was raised to a temperature of 1°C every 5 hours to finally reach 30°C. Circulation was made using a circulation filtration means, and only the amount reduced by evaporation was supplemented with breeding water.

After 48 hours, feed was fed twice a day, at 12 hour intervals, and the animals were bred for 6 months, and the mortality rate was confirmed.

The mortality rates of eels raised in each tank are shown in Table 1 below.

[Table 1]

As shown in Table 1 above, it can be seen that the intermediate seeds bred at 10 g or less in low-salt water have a high mortality rate and thus no productivity. It was confirmed that intermediate seeds bred with less than 10 g of salt were well adapted to seawater and were bred as adults.

However, the average object weight of adult fish raised with medium seed bred with low salt at 10 g was higher than that of adult fish raised with medium seed bred with low salt at 30 g or 50 g.

Again, considering that the expression time of growth hormone according to the activation of salt cells is performed before and after growth to 10 g, 30g or 50g medium-weight seeds have a later intensive growth period compared to the expression time of growth hormone, so the overall growth is affected. is considered crazy

Example 4 Farming of Far Eastern eels in seawater

In 8 round tanks with a diameter of 2 m, two breeding waters of fresh water, salinity 5.0, 15.0, and 30.0 psu were prepared.

Each tank was stocked with 500 intermediate seeds produced by feeding for 2 months in the freshwater and low-salt breeding water of Example 2. (Individual weight forms 10g when fed for 2 months)

In each tank, the water temperature at the time of stocking was 20℃, and the plastic bag containing the intermediate seeds was immersed in the tank for about 1 hour, and the intermediate seeds were released into the tank after the temperature was adjusted.

The dissolved oxygen of the breeding water was maintained at 7-12 mg/L through an oxygen supply means, and a water flow was formed through a water wheel. The breeding water in the tank was raised to a temperature of 1°C every 5 hours to finally reach 30°C.

After 48 hours, feed was fed twice a day, at 12 hour intervals, and the animals were bred for 6 months to raise adult eels.

At this time, the water tank was circulated using the circulation filtration means of the present invention, and only the amount reduced by evaporation was supplemented with breeding water.

The mortality rates of eels raised in each tank are shown in Table 2 below.

[Table 2]

As shown in Table 2 above, intermediate seeds raised at low salinity show mortality similar to freshwater even when stocked and reared in high salinity breeding water corresponding to seawater, so productivity is maintained,

The mortality rate of intermediate seeds raised in freshwater was more than twice higher than that of intermediate seeds produced in salinity when reared in seawater with high salinity, indicating that productivity was lowered.

This is presumed to be related to the activation of salt cells, and it was found that the intermediate seeds raised in salinity water were better adapted to salt water or seawater (more than 20ppt) when producing intermediate seeds.

In addition, it was observed that the eels raised in salinity water were superior in vitality and color to those of general freshwater cultured fish, and showed good reactivity to feed.

The average weight of each individual eel raised in each tank was measured and shown in Table 3 below.

[Table 3]

The total weight of the eels raised in each tank was measured and shown in Table 4 below.

[Table 4]

As shown in Tables 3 and 4, it was found that the individuals produced as intermediate seeds in salinity breeding water and nurtured as adults in seawater showed a high overall weight.

Therefore, according to the degree of activation of salt cells, if the individual weight is grown to 10 g, where the expression of growth hormone is grown for 2 months in low-salt breeding water, and grown as an adult fish in seawater, direct shipment is possible without the breeding process, resulting in weight loss due to livestock. can decrease and increase the income of fishermen.

Example 5 - Sensory test

The blind test method was conducted on 40 villagers near the farm in Taean-gun, Chungcheongnam-do.

After cultivating the intermediate seeds in the low-salt breeding water of Example 4, eels from the Far East were used as adults in the breeding water with a salinity of 30 psu, which is seawater.

As a comparison group, eels from the Far East that were bred the same as in the present invention were selected as follows. Company C’s Yeongam-gun production, Comparative group 4-online sales Company D’s Seomjingang production)

The Far East eels used for sensory testing were carried out without a separate breeding process, after arrest, removing the head, internal organs, and midbones, and roasting them over charcoal.

In addition, salt or seasoning was not added for accurate sensory testing.

Each item was evaluated as 5. very good, 4. good, 3. average, 2. bad, and 1. very bad on a 5-point scale, and the average of the evaluation results is summarized in Table 5.

[Table 5]

As a result of the evaluation, in Example 4, a high score was obtained in all of the measurement items. Because it was bred in salty seawater, it was rated as having excellent taste and meat quality without any odor, and received superior scores in terms of meat quality without going through a livestock breeding process.

As for other evaluation opinions, it was evaluated that the eel of Example 4 did not have the characteristic greasiness of the eel, had a strong light taste, and had a slightly seasoned taste.

10: Adult fish development system
20: high salt water tank
30: circulation filtration means
31: filtration filter 32: biological filtration tank
33: UV sterilizer
40: oxygen supply means
41: oxygen supply 42: oxygen dissolver
P: pump

Claims (8)

In the method for aquaculture of descent fish using seawater,
an intermediate seed production process of producing 0.2-2.0 psu of low-salt breeding water by mixing seawater and freshwater, and producing intermediate seeds through fertilization of fry in the prepared low-salt breeding water;
A method for cultivating descent fish, comprising the steps of: using seawater to produce 10-33 psu of high-salt breeding water, and cultivating adult fish by acclimatizing intermediate seeds to the prepared high-salt breeding water. The method of claim 1,
The intermediate seed production process is
A low-salt breeding water production step of mixing seawater and fresh water to produce 0.2-2.0 psu of low-salt breeding water;
A stocking environment creation step of storing the prepared breeding water in a low-salt water tank, but creating a stocking environment for fry generating a water flow while changing the low-salt breeding water at a rate of 2-3 ton/h;
stocking the fry caught in the brackish pond in the low-salt water tank where the stocking environment is created, and acclimatizing the fry without feeding;
A mouthwash step of supplying mouthwash feed to a low-salt water tank to increase adaptability to feed;
A method for breeding descent fish, characterized in that it comprises; an intermediate seed production step of cultivating the medium seed size through feed feeding when the mouth-to-mouth is finished. 3. The method of claim 2,
In the intermediate seed production process,
In the stocking environment creation step and the frying step, the low-salt breeding water temperature is set to 15~20℃ so that the stocking takes place and then acclimatizes for 36~72 hours;
In the mouthing step, the low-salt breeding water temperature is raised by 1°C every 3 to 5 hours to make it 28-31°C. The method of claim 1,
The adult language development process is
Preparation of high-salt stocking water with a salinity of 10 to 33 psu using seawater;
A high salt breeding water quality management step of storing the prepared high salt breeding water in a high salt water tank, but managing the high salt breeding water through a circulation filtration means;
Intermediate seed acclimatization step of transferring and stocking the intermediate seeds produced in the intermediate seed production process;
An adult fish breeding step of supplying feed to nurture an adult fish; 5. The method of claim 4,
In the intermediate seed acclimatization stage of the adult fish development process,
Set the high-salt stocking water temperature to 15~25℃ to stock the intermediate seeds, then raise the high-salt breeding water temperature by 1℃ every 3~5 hours to 28~31℃, and allow it to acclimatize for 36~72 hours without feeding. A method for aquaculture of descent fish, characterized in that 5. The method of claim 4,
The circulation filtration means,
Part of the high salt breeding water in the high salt water tank is circulated by a pump, and a filter filtration step by a physical filtration filter, a biological filtration step by a biological filtration tank, and a UV sterilization step by UV irradiation are performed to achieve purification. Methods for cultivating descent fish. According to claim 1,
Dissolved oxygen in the low-salt breeding water and the high-salt breeding water is maintained at 7-12 mg/L by an oxygen supply means. The method of claim 1,
The descent fish culture method, characterized in that any one of japonica (Anguilla japonica), bicola (Anguilla Bicolor), and malmorata (Anguilla marmorata).

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