KR102241319B1 - Culture method of mud flat crab, Chasmagnathus convexus - Google Patents

Abstract

The present invention relates to a method for producing artificial seeds of sea crabs carried out indoors. (A) Mother sea crabs were subjected to a light cycle of 14 to 16 hours and a dark cycle of 8 to 10 hours at a water temperature of 23 to 28 °C for 28 to 32 days. Repeatedly forming an outer envelope with a fertilized egg attached to the shell of the mother crab; (B) hatching the fertilized eggs into zoea larvae by maintaining the embryonated eggs under the same conditions as in step (A) for 15 to 20 days; (C) feeding the hatched zoea larvae at a water temperature of 20 to 35° C. and maintaining them for 12 to 18 days to transform into megalopa larvae in which claws are formed; (D) feeding the Megalopa larvae at a water temperature of 20 to 35° C. and maintaining them for 5 to 10 days to transform them into young crabs; And (E) rearing young crabs at a water temperature of 20 to 35° C. in an environment covered with gravel of 5 mm or more in diameter; by including, fertilized eggs can be obtained at a desired time through early incubation of the legal protected species. The survival rate can be improved while shortening the rearing period of larvae.

Description

Artificial seed production method of mud flat crab performed indoors{Culture method of mud flat crab, Chasmagnathus convexus}

The present invention relates to a method for producing artificial seeds of sea crabs performed indoors to improve survival while shortening the breeding period of larvae hatched from the fertilized eggs and to obtain fertilized eggs at a desired time through early incubation of sea crabs, which are legally protected species. About.

Chasmagnathus convexus is a rare species distributed in Far East Asia such as Japan, China, and Taiwan, including Korea. In Korea, it lives by digging holes in grasslands, piles of stones, ditches and wetlands above the estuary and intertidal zone of the west and south seas and Jeju coast. do. It is a nocturnal nature that lives in a hole during the day and moves in search of food at night, and is known as omnivorous like other crabs living on land.

In the spring, nestling mother clams can be identified, and larvae hatched into zoea develop into megalopa and juvenile stages while living in the sea. After undergoing molting, he transformed into a crab and lived on land.

These sea crabs have recently disappeared due to artificial interference from estuary and coastal reclamation and pollution, and a small number of individuals are found only in some areas. The Ministry of Environment has designated sea crabs as endangered wildlife class II and the Ministry of Oceans and Fisheries as protected marine organisms and is legally managed.

In order to restore the natural population of the legally protected species, it is essential to restore the environment of the habitat, and the natural population can be restored more quickly through the production of indoor artificial seeds.

For indoor artificial seed production, it is necessary to establish a detailed method of the whole process from rearing management of mother clams to the period of floating larvae and growing into young crabs before release.

On the other hand, crab farming such as blue crabs, blue crabs, and snow crabs belonging to crustaceans is usually reared for a short period of time after purchasing an incubated mother crab, allowing the mother to hatch the eggs incubated on its own. In the Zoea period, Brachionus spp. ) And Altemia nouplius, and after the Megalopa period, meat such as shellfish and shrimp are ground and raised for about 1 month, and the seed production process is terminated. The difficulty in the seed production process is that first, most of the mother crabs are purchased according to the natural spawning period, so if the seed production period fails in the middle of the seed production process, the preparation period for reproduction is short, making it difficult to produce seeds for the year. ; Second, it is a problem due to the failure of the optimal feed density during the breeding period of the larvae. If the number is small, the growth and survival rate decreases, and if there are many, there are difficulties such as water quality management due to the excess remaining food organisms. Density estimation is very important; Third, since Megalopa period, the damage caused by official phenomena is large, so various methods (injection of light shields, nets, etc.) have been applied to breed them. However, in the stage of young crabs living on the floor, official restraint during the swimming period. The method has limitations and cannot be reared for a long period of time, so it is transformed into young crabs and sold as seeds for release within a short period of time.

Unlike blue crabs, snow crabs, and blue crabs for aquaculture that always live in the water, sea crabs are legally protected species that live on land. Since there is a difficulty that must be progressed, and there is a specificity for each species even if the same kind is the same, the breeding management method according to the characteristics of each species must be specified.

Accordingly, the present invention was completed so that it can be grown as a seed for radiation to increase the natural population of a rare species, sea crab, and to achieve continuous species preservation in an indoor water tank.

Korean Patent Registration No. 1497119 Korean Patent Registration No. 0991274

It is an object of the present invention to provide a method for producing artificial seeds of sea crabs performed indoors so that fertilized eggs can be obtained at a desired time through early incubation of sea crabs, which are legally protected species, and shorten the breeding period of larvae and improve the survival rate. have.

In addition, another object of the present invention is to provide a sea crab produced indoors according to the above production method.

In addition, another object of the present invention is to provide a method for inducing early incubation of the statutory protected species.

In order to achieve the above object, the method for producing artificial seeds of sea crabs carried out indoors of the present invention comprises (A) a mother sea crab at a water temperature of 23 to 28° C. with a light cycle of 14 to 16 hours and a dark cycle of 8 to 10 hours. Repeating for 28 to 32 days to form an outer oocyte with a fertilized egg attached to the shell of the mother's clam; (B) hatching the fertilized eggs into zoea larvae by maintaining the eggs for 15 to 20 days under the same conditions as in step (A); (C) feeding the hatched zoea larvae at a water temperature of 20 to 35 °C and maintaining them for 12 to 18 days to transform them into megalopa larvae in which claws are formed; (D) feeding the Megalopa larvae at a water temperature of 20 to 35° C. and maintaining them for 5 to 10 days to transform them into young crabs; And (E) rearing the young crabs at a water temperature of 20 to 35° C. in an environment covered with gravel of 5 mm or more in diameter.

In the step (A), the illuminance of the light cycle may be 900 to 1500 Lux.

In the step (A), the mother sea crab, which was bred at 10 to 12°C, can be reared by repeating the light cycle and the dark cycle at a water temperature of 23 to 28°C.

In the step (C), the hatched zoea larvae can be grown in brine with a salt concentration of 10 psu or more.

In the step (C), the zoea larvae are grown in brine with a salt concentration of 10 to 35 psu at a water temperature of 22 to 25 °C, or brine with a salt concentration of 15 to 35 psu at a water temperature of 26 to 34 °C. Can be.

It may be rotifer fed in step (C), Altemia nouplii, or a mixture thereof.

In the step (C), 10 to 80 individuals/ml of rotifer, 1 to 10 individuals/ml of Altemia nouplius, or a mixture of rotifers and Altemia nouplii of 1:0.03 to 0.2 may be mixed.

In the step (D), megalopa larvae can be grown in brine with a salt concentration of 10 psu or more.

In the step (D), the megalopa larvae grow into brine with a salt concentration of 20 to 35 psu at a water temperature of 22 to 23 °C, and grow into brine with a salt concentration of 10 to 35 psu at a water temperature of 24 to 30 °C, Alternatively, it may be grown in brine having a salt concentration of 15 to 35 psu at a water temperature of 31 to 34 °C.

The food in step (D) may be 10 to 20 individuals / ml of Altemia nouplius.

In the step (E), young crabs may be reared by additionally installing a light-shielding film to provide a hiding place.

In the step (E), young crabs may be grown in fresh water (saline concentration of 0 psu) or salt water having a salt concentration of 1 to 35 psu at a water temperature of 20 to 35°C.

In the step (E), a mixture of shellfish and young shrimp may be supplied as food.

In steps (C) to (E), the amount of dissolved oxygen in water may be 4 to 10 mg/L.

In addition, the sea crab produced indoors of the present invention for achieving the other object described above may be bred indoors according to the above production method.

In addition, the method of inducing early incubation of the mother clam of the present invention for achieving the above-described another object is, the mother clam reared at 10 to 12° C. is immediately reared at a water temperature of 23 to 28° C. at a water temperature of 14 to 16 hours and a light cycle of 8 to 16 hours. It may include the step of repeating the dark cycle of 10 hours for 28 to 32 days to form an outer oocyte with a fertilized egg attached to the shell of the mother clam.

If carried out by the production method of the present invention, it is possible to extend the seed production period by obtaining fertilized eggs at a desired time through early incubation of sea crabs, which are legally protected species. In addition, it is possible to increase the survival rate of larvae by providing an appropriate water temperature and salt concentration during the floating larvae of the sea crab, and at the same time, it is possible to prevent the loss of food and improve the survival rate of the larvae by specifying the supply density of the prey organisms.

In addition, it is possible to prevent the decline in survival rate due to long-term rearing of young crabs by putting gravel and a shading film of 5 mm or more in diameter at the bottom of the tank in order to prevent the decrease in survival rate of young crabs due to the pitting phenomenon. This can be of great help in increasing the number of natural populations through radiation by preserving the species by indoor breeding of the legally protected species, and simultaneously producing large quantities of seeds from limited mothers.

1 is a flow chart showing a process of breeding to grow young crabs after inducing early incubation of mother crabs according to an embodiment of the present invention.
2 is a graph showing the survival rate of Zoea larvae by salt concentration according to water temperature.
3 is a graph showing the amount of intake of rotifers, which are food organisms, as they grow in the order of zoea stage I to stage IV.
FIG. 4 is a graph showing the amount of intake of the food organism Altemia nouplius as it grows in the order of zoea stage Ⅰ to stage Ⅳ.
5 is a graph showing the survival rate of megalopa larvae according to salt concentration according to water temperature.
Figure 6 is a graph showing the amount of feeding intake of the food organism Altemia nouplyus as Megalopa larvae grow.
7 is a graph showing the survival rate of young crabs by salt concentration according to water temperature.
Figure 8 is a graph measuring the formula prevention method of young crabs.

The present invention relates to a method for producing young crabs carried out indoors to improve the survival rate while shortening the breeding period of the larvae hatched from the fertilized eggs and to obtain fertilized eggs at a desired time through early incubation of the legally protected species. will be.

Specifically, the present invention induces early incubation of the mother's clam through water temperature and photoperiod control; Water temperature and salt concentration suitable for the period of floating larvae zoea and megalopa, and feed density according to food type; And it relates to a breeding method for preventing formula (共食) suitable water temperature and salt concentration for breeding in the early childhood.

Hereinafter, the present invention will be described in detail.

As shown in Fig. 1, the method of producing the young sea crab of the present invention includes (A) the mother sea crab at a water temperature of 23 to 28 °C for a light cycle of 14 to 16 hours and a dark cycle of 8 to 10 hours from 28 to 32. Repeating for a period of days to form an outer envelope with a fertilized egg attached to the shell of the mother clam; (B) hatching the fertilized eggs into zoea larvae by maintaining the eggs for 15 to 20 days under the same conditions as in step (A); (C) feeding the hatched zoea larvae at a water temperature of 20 to 35 °C and maintaining them for 12 to 18 days to transform them into megalopa larvae in which claws are formed; (D) feeding the Megalopa larvae at a water temperature of 20 to 35° C. and maintaining them for 5 to 10 days to transform them into young crabs; And (E) rearing the young crabs at a water temperature of 20 to 35° C. in an environment covered with gravel of 5 mm or more in diameter.

First, in the step (A), the mother crab that was raised at a low temperature of 10 to 12 ℃ similar to the outdoor environment is immediately repeated at a water temperature of 23 to 28 ℃ without increasing the temperature. Forms an exosome entity with a fertilized egg attached to the shell.

At this time, the light cycle is 14 to 16 hours and the dark cycle is 8 to 10 hours, and the illuminance at the light cycle is 900 to 1500 Lux, preferably 1000 to 1200 Lux. In general, in order to raise the mother crab that was living at a low temperature (water temperature) at a relatively high temperature (water temperature), the water temperature is gradually increased over time, but in the present invention, the water temperature is increased from a low temperature to a high temperature immediately, but By performing the and dark cycle according to the above time, early incubation can be induced and fertilized eggs can be obtained at any time desired.

If the water temperature is gradually increased over time and the light cycle and the dark cycle are not repeatedly performed, the incubation is not performed earlier than the case where the water temperature is increased and the light cycle and the dark cycle are repeatedly performed; If the water temperature is gradually increased over time and the light cycle and the dark cycle are repeatedly performed, early incubation is induced, but the amount of fertilized eggs may be small.

When the illuminance is less than the lower limit during the bright period, early eggs are not induced and a large amount of fertilized eggs cannot be obtained, and when the illuminance exceeds the upper limit, the content of the fertilized eggs may rapidly decrease.

Next, in the step (B), the embryonated eggs are maintained for 15 to 20 days under the same conditions as in the step (A), so that the fertilized eggs are hatched into zoea larvae.

Next, in the step (C), the hatched zoea larvae are maintained for 12 to 18 days while feeding at a water temperature of 20 to 35 °C to pass through the zoea Ⅰ to Ⅳ periods, thereby forming megalopa larvae. Transform.

After transferring the zoea larvae hatched in step (B) to another water tank, they are grown in brine with a water temperature of 20 to 35°C and a salt concentration of 10 psu or more. The growth of the zoea larvae differs depending on the water temperature and the concentration of salt. Specifically, when the water temperature is 22 to 25 °C, the survival rate is high under the salt water with the salt concentration of 10 to 35 psu, and when the water temperature is 26 to 34 °C The survival rate is high under saline with a salt concentration of 15 to 35 psu.

Feeding organisms supplied to the zoea larvae are rotifers, hatched Altemia nouplii, or mixtures thereof. If the feed density is low, the growth rate and survival rate of zoea larvae may decrease, and if the feed density is high, the excess feed organisms grow in the tank and provide the cause of water quality change. The survival rate of Zoea larvae decreases rapidly. Accordingly, food organisms must be supplied in an appropriate amount. When supplied with rotifer alone, a density of 10 to 80 individuals/ml, when supplied with Altemia nouplii alone, a density of 1 to 10 individuals/ml, and rotifer and Altemia noupley When supplying a mixture of mouses, rotifers and Altemia nouplius are supplied at a mixed density at a population ratio of 1:0.03 to 0.2 per ml, but it is preferable to increase the supply amount as they grow.

Next, in the step (D), the Megalopa larvae are fed at a water temperature of 20 to 35° C. and maintained for 5 to 10 days to transform into young crabs.

The megalopa larvae are grown in brine with a water temperature of 20 to 35° C. and a salt concentration of 10 psu or more. The growth of the Megalopa larvae differs depending on the water temperature and the concentration of salt. Specifically, when the water temperature is 22 to 23 °C, the survival rate is high under the salt water with the salt concentration of 20 to 35 psu, and when the water temperature is 24 to 30 °C The survival rate is high in brine with a salt concentration of 10 to 35 psu, and the survival rate is high in brine with a salt concentration of 15 to 35 psu at a water temperature of 31 to 34°C.

It is preferable to use the hatched Altemia nouplius alone as the food organisms supplied to the Megalopa larvae in terms of improving the growth rate and minimizing changes in water quality. If the feed density is low, the survival rate of Megalopa larvae may decrease, and if the feed density is high, the excessively administered prey organisms grow in the tank and provide the cause of water quality change. It is preferable to supply Altemia nouplius at a density of 10 to 20 individuals/ml, because the survival rate of is rapidly decreased.

Next, in step (E), the young crabs are reared and grown under a water temperature of 20 to 35° C. in an environment covered with gravel of 5 mm or more in diameter.

The young crabs are grown in fresh water (saline concentration of 0 psu) or salt water having a salinity concentration of 1 to 35 psu while the water temperature is 20 to 35°C. The young crabs show a survival rate of 90% or more under fresh water or salt water having a water temperature and salt concentration within the above range.

The young crabs grow while continuing to molt. After molting, when the crust is weak, it is predated by other crabs, which is the main cause of the decline in the survival rate during breeding. For long-term breeding while maintaining a high survival rate of crabs, it is necessary to provide a suitable shelter in the breeding tank.

In order to prevent such a decline in survival rate of young crabs, an environment covered with gravel of 5 mm or more in diameter is provided, and a shielding film that can be used as a hiding place for a higher survival rate is also provided. In the case of breeding under the shading film alone or in the sand with a diameter of 2 mm or less instead of gravel with a diameter of 5 mm or more, the survival rate may decrease.

In addition, the feed of the young crab is not particularly limited, but preferably a mixture of shellfish and young shrimp may be mentioned, and nutrients can be supplemented by mixing the mixed feed of marine fish and shrimp.

In the steps (C) to (E), air is injected into fresh water or brine so that the amount of dissolved oxygen is 4 to 10 mg/L, preferably 5 to 7 mg/L, thereby inducing faster growth and improving the water quality in the water tank. Improves the survival rate.

Hereinafter, a preferred embodiment is presented to aid in the understanding of the present invention, but it is obvious to those skilled in the art that various changes and modifications are possible within the scope of the present invention and the scope of the technical idea, but the following examples are only illustrative of the present invention, It is natural that such modifications and modifications fall within the scope of the appended claims.

Example. Early incubation and early incubation of the mother's sea crab

1. Early incubation incubation of the mother's sea crab

After obtaining the permission from the competent local environmental agency, in May 2017, two pairs of male and female captured in the intertidal zone of Seongsan-eup, Jeju-do, were minced in a bottom filtration breeding tank. It was supplied, and the breeding environment was raised indoors similar to the outdoor environment. The water temperature at this time was about 10 °C, and the photoperiod was under the same conditions as nature, and the light and dark cycle was approximately 14 hours in the light cycle and 10 hours in the dark cycle.

On January 1 of the following year, the water temperature of the tank in which the mother's crab was reared was raised to 25 ℃, and the photoperiod conditions were adjusted by installing a heater and a timer for 15 hours in the light cycle and 9 hours in the dark cycle. During the bright period, the surface roughness of the light was set to be about 1,000 Lux. After 30 days, it was confirmed that the individual embryos attach the fertilized eggs to the shell.

Therefore, in order to induce early incubation of the mother's clam, the water temperature is raised to 25 ℃, and rearing is controlled from the photoperiod corresponding to the winter solstice to the photoperiod, which corresponds to the summer solstice, to 15 hours in the light cycle and 9 hours in the dark cycle. It is desirable to do it.

2. Zoea larvae breeding management

The incubated mothers were continuously reared under the same conditions as the breeding environment for the early incubation test, and after 17 days, as the fertilized eggs hatched into Zoea, the Zoea larvae were transferred to a 200L plastic tank. At this time, the water temperature and salt concentration of the brine contained in the tank to which the Zoea larvae were transferred were adjusted differently, and the dissolved oxygen amount of about 6 mg/L or more was maintained using an oxygen generator.

<Test Example_1>

Test Example 1. Confirmation of water temperature and salt concentration during growth of Zoea larvae

In order to find out the proper water temperature and salt concentration of Zoea larvae, salt concentration is adjusted in a 6 well culture plate and oxygen is administered to Zoea stage 1 larvae 1 day after hatching into Zoea larvae. After 10 ml of saturated breeding water was added, 5 Zoea larvae were added to each well, and a total of 6 repeats were placed. The water temperature for the adaptability analysis was 22, 25, 28, 31, 34 ℃, and the salt concentration was set to 0, 5, 10, 15, 20, 25, 30, 35 psu, and then the water temperature and the salt test zone were mixed together. Experimented.

2 is a graph showing the survival rate of Zoea larvae by salt concentration according to water temperature.

As shown in FIG. 2, the survival rate according to the water temperature and salinity of the Zoea stage 1 larvae was confirmed to have a survival rate of 90% or more in all water temperature experimental groups having a salinity concentration of 15 psu or more.

On the other hand, it was confirmed that all of the zoea larvae were killed in the experimental group with a salinity of 0 psu and 5 psu regardless of the water temperature.

Therefore, if the salinity is 15 psu or more, a high survival rate can be expected regardless of the water temperature range (22 to 34 °C), but specifically, when the salt concentration is 10 to 35 psu at a water temperature of 22 to 25 °C and the salt content of 26 to 34 °C A high survival rate was confirmed when the concentration of salt was 15 to 35 psu at water temperature. In the case of water temperature, the higher the water temperature, the more difficult the dissolved oxygen saturation and water quality management are, so 22 to 31 ℃ is preferable.

Test Example 2. Density of prey organisms supplied to Zoea larvae

Rotifer, Altemia nouplii, or mixtures thereof were used as food organisms of the zoea group. In order to determine the proper feed density of food organisms in the zoea, a 25 ml polyethylene bottle is filled with oxygen-saturated 20 ml of seawater (saline concentration: 35 psu), and the rotifer is 2.5, 5, 10, 20, 40, 80, At a density of 160 individuals/ml, freshly hatched Altema nouplii were placed at a density of 1, 2.5, 5, 10, 20, 40 individuals/ml. Two zoea larvae were put in each density test zone, and the experiment was carried out in an incubator controlled at 25°C, and the test zone was repeated 5 times. It was found that the sea crab molts 4 times during the zoea period, and experiments were conducted up to the 4th stage of the zoea, and the experiment was performed on the subjects 1 day after molting in consideration of the decrease in the amount of eating after molting.

FIG. 3 is a graph showing the intake of rotifers, which are food organisms, as they grow in the order of zoea stage Ⅰ to stage Ⅳ, and FIG. 4 is a prey organism, Altemia noupley, as they grow in the order of zoea stage Ⅰ to stage Ⅳ. It is a graph showing the amount of consumption of mouse.

As shown in FIG. 3, the amount of rotifer feeding increased as the zoea larvae grew, and the amount of feeding increased as the rotifer food concentration increased, but the experimental group fed at the highest density showed a rather low feeding amount.

Therefore, when breeding by supplying only rotifers, 10 to 20 individuals/ml in Joea stage I, 20 to 40 individuals/ml in Joea stage II, 40 to 60 individuals/ml in Joea stage III, and 60 in Joea stage IV. When fed at -80 individuals/ml, the maximum food intake was confirmed. Preferably, the amount of food is increased as the zoea grows, but is supplied at a density of 20 to 80 individuals/ml.

In addition, as shown in FIG. 4, as the zoea larvae grow and the food density of Altemia nouplii increases, the maximum feeding amount increased, but it was confirmed that the feeding amount decreased at the maximum food density.

Therefore, in the case of supplying only Altemia nouplii alone, the feed density gradually increases as the zoea larvae grow, but 1 individual/ml in the zoea stage I, 1 to 3 individuals/ml in the zoea stage II, and The maximum amount of food intake was confirmed when feeding 3 to 5 individuals/ml in the Child III stage and 5 to 10 individuals/ml in the Zoea IV stage. Preferably, 1 to 10 individuals/ml are supplied as a whole during zoea growth, and more preferably, the amount of Altemia nouplius intake is small in the first and second phases of Zoea, so Altemia nouplius is supplied from the third zoea.

On the other hand, in the case of using a mixture of rotifer and Altemia nouplius as food organisms for Zoea larvae, a mixture of rotifer and Altemia nouplius at an individual number ratio of 1:0.03 to 0.2, preferably 10 to 40 individuals of rotifers /ml, a mixture of 0.5 to 5 individuals/ml of Altemia nouplius is used.

Example. Megalopagi

3. Megalopa larvae breeding management

As the zoea larvae grew, they transformed into megalopa larvae on the 15th day.At this time, the water temperature and salt concentration of the brine contained in the water tank were adjusted differently after the transformation into megalopa larvae, and about 6 mg/L or more using an oxygen generator. The amount of dissolved oxygen was maintained.

<Test Example_2>

Test Example 3. Confirmation of water temperature and salt concentration during growth of megalopa larvae

In order to find out the proper water temperature and salt concentration of Megalopa larvae, target Megalopa larvae 1 day after transformation into Megalopa, the salt concentration is adjusted in a 6 well culture plate and oxygen-saturated breeding water 10 After adding ml, 1 Megalopa larvae were added to each well, and a total of 10 repeats were placed. The water temperature for the adaptability analysis was 22, 25, 28, 31, 34 ℃, and the salt concentration was set to 0, 5, 10, 15, 20, 25, 30, 35 psu, and then the water temperature and the salt test zone were mixed together. Experimented.

5 is a graph showing the survival rate of megalopa larvae according to salt concentration according to water temperature.

As shown in Figure 5, the survival rate according to the water temperature and salinity of the Megalopa larvae confirmed the survival rate of 90% or more in all the water temperature experimental zones with a salinity concentration of 15 psu or higher, and the higher the salinity concentration, the higher the survival rate at a lower water temperature. I did.

On the other hand, it was confirmed that all of the megalopa larvae died in all the water temperature experimental zones with a salinity concentration of 0 psu and in the experiment zones with a salinity concentration of 5 psu and 34 ℃.

Therefore, if the salinity is 15 psu or more, a high survival rate can be expected regardless of the water temperature range (22 to 34 °C), but specifically, when the salt concentration is 20 to 35 psu at a water temperature of 22 to 23 °C, the temperature of 24 to 30 °C A high survival rate was confirmed when the salt concentration at the water temperature was 10 to 35 psu and the salt concentration at the water temperature of 31 to 34 °C was 15 to 35 psu. In the case of water temperature, the higher the water temperature, the more difficult the dissolved oxygen saturation and water quality management are, so 22 to 31 ℃ is preferable.

Test Example 4. Density of prey organisms supplied to megalopa larvae

It is preferable to use Altemia nouplius alone as the food organism of the Megalopagi. To determine the feed density of Altemia nouplius, a 25 ml polyethylene bottle was filled with 20 ml of oxygen-saturated seawater, and freshly hatched Altemia nouplius 1, 2.5, 5, 10, 20, 40 individuals/ After adding to the density of ml, 1 individual Megalopa larvae were added. The experiment was carried out in an incubator controlled at 25° C., and the experiment was repeated 5 times.

Figure 6 is a graph showing the amount of feeding intake of the food organism Altemia nouplyus as Megalopa larvae grow.

As shown in Fig. 6, when the Megalopa larvae were added at a density of 10 to 20 individuals/ml, a large amount of food was fed, and the feeding amount increased as the food concentration of Altemia nouplii increased, but the feeding amount was increased, but it was supplied at the highest density. One experimental group showed a rather low diet. Accordingly, it is preferable to supply Altemia nouplius at a density of 10 to 20 individuals/ml.

Example. Young

4. Young crab breeding management

As the megalopa larvae grew, they transformed into young sea crabs on the 8th day, and after the transformation into young sea crabs, the water temperature and salt concentration of the brine contained in the water tank were adjusted differently, and an amount of dissolved oxygen of about 6 mg/L or more using an oxygen generator. Was to be kept.

<Test Example_3>

Test Example 5. Confirmation of water temperature and salt concentration during growth of young crab

In order to find out the proper water temperature and salt concentration of young sea crabs, breeding water in which the salt concentration is adjusted in a 6-well culture plate and oxygen-saturated 10 for young sea crabs 1 day after transformation into young sea crabs. After adding ml, one young crab was added to each well, and a total of 10 repetitions were placed. The water temperature for the adaptability analysis was 22, 25, 28, 31, 34 ℃, and the salt concentration was set to 0, 5, 10, 15, 20, 25, 30, 35 psu, and then the water temperature and the salt test zone were mixed together. Experimented.

7 is a graph showing the survival rate of young sea crabs according to salt concentration according to water temperature.

As shown in Figure 7, the survival rate according to the water temperature and salinity of the young sea crab showed a survival rate of 90% or more in all the water temperature and all the salt concentration experimental zone, it was confirmed that the adaptability to the salt concentration increases as it grows.

Therefore, a high survival rate can be expected regardless of all water temperature ranges (22 to 34 ℃), but if the water temperature is high, 22 to 31 ℃ is preferable because dissolved oxygen saturation and water quality management are difficult, and the salt concentration is judged to be irrelevant. do.

Test Example 6. Confirmation of the method of preventing formula of young crab

In order to prevent the occurrence of pitting phenomena of eating each other, sand with a diameter of 2 mm or less, diameter of 5 to 10, in addition to the light shielding film with a light shielding rate of 55%, which is generally used in order to understand the effective pitting prevention method of young sea crabs. Gravels of mm and large gravel with a diameter of 1 cm or more were added to compare and analyze the survival rate. After filling 10 L of seawater in a plastic square tank 36 cm wide, 28 cm long, and 19 cm high, 50 young crabs were accommodated, and the experiment was conducted for 2 weeks while supplying air.

Figure 8 is a graph measuring the formula prevention method of young crab.

As shown in FIG. 8, it was confirmed that the two experimental spheres in which gravel with a diameter of 5 mm or more was added had a survival rate of 96.0% or more, showing the best survival rate. In the case of inserting gravel with a diameter of 5 mm or more, it is judged to have a high survival rate because it provided enough space for a young crab with a carapace of about 2.0 mm to hide.

On the other hand, it was confirmed that the survival rate of the control group to which nothing was added had a survival rate of 48.0%, the survival rate of the test group with a light-shielding film (55% shading rate) was 84.0%, and the test group with sand having a diameter of 2.0 mm or less was 78.0%. . The experimental zone in which the sand was introduced did not find a space in the sand for young sea crabs to hide, and the survival rate seemed to be low because the force was weak to infiltrate into the sand.

In order to improve the survival rate in the juvenile period, it is preferable to put a light-shielding film together with gravel of 5 mm or more in diameter.

Claims (16)

(A) The mother's clam, which was bred at 10 to 12° C., was repeated at a water temperature of 23 to 28° C. for 14 to 16 hours and a dark cycle of 8 to 10 hours for 28 to 32 days. Forming an external egg object with a fertilized egg attached;
(B) hatching the fertilized eggs into zoea larvae by maintaining the ovarian eggs under the same conditions as in step (A) for 15 to 20 days;
(C) feeding the hatched zoea larvae at a water temperature of 20 to 35° C. and maintaining them for 12 to 18 days to transform into megalopa larvae in which claws are formed;
(D) feeding the Megalopa larvae at a water temperature of 20 to 35° C. and maintaining them for 5 to 10 days to transform them into young crabs; And
(E) rearing the young crabs at a water temperature of 20 to 35° C. in an environment covered with gravel of 5 mm or more in diameter. The method of claim 1, wherein in the step (A), the illuminance of the light cycle is 900 to 1500 Lux. delete The method of claim 1, wherein in the step (C), the hatched zoea larvae are grown in brine having a salt concentration of 10 psu or more. The method of claim 1, wherein the Zoea larvae in the step (C) are grown in brine having a salt concentration of 10 to 35 psu at a water temperature of 22 to 25 °C, or a salt concentration of 15 to a water temperature of 26 to 34 °C. A method for producing artificial seeds of sea crab, characterized in that grown with 35 psu of brine. The method according to claim 1, characterized in that it is rotifer fed in step (C), Altemia nouplii, or a mixture thereof. The method according to claim 1, wherein 10 to 80 individuals/ml of rotifer, 1 to 10 individuals/ml of rotifer, or rotifer and Altemia nouplii are mixed at a population ratio of 1:0.03 to 0.2. Artificial seeds production method of sea crab, characterized in that the mixture. The method of claim 1, wherein in the step (D), megalopa larvae are grown in brine having a salt concentration of 10 psu or more. The method of claim 1, wherein in the step (D), the megalopa larvae grow in brine with a salt concentration of 20 to 35 psu at a water temperature of 22 to 23 °C, and a salt concentration of 10 to 35 at a water temperature of 24 to 30 °C. A method for producing artificial seeds of sea crabs, characterized in that they are grown in brine with psu, or brine with a salt concentration of 15 to 35 psu at a water temperature of 31 to 34°C. The method of claim 1, wherein in the step (D), 10 to 20 individuals/ml of Altemia nouplii are fed in the step (D). The method of claim 1, wherein in the step (E), a light shielding film is additionally installed and reared to provide a hiding place. The method of claim 1, wherein in the step (E), the young crabs are grown in fresh water or brine having a salt concentration of 1 to 35 psu at a water temperature of 20 to 35 °C. The method of claim 1, wherein in the step (E), a mixture of shellfish and young shrimp is supplied as food. The method according to any one selected from the group consisting of claims 1, 2, and 4 to 13, wherein the amount of dissolved oxygen in water in steps (C) to (E) is 4 to 10 mg/L. How to produce artificial seeds of sea crab. delete Fertilized eggs are attached to the shells of the mother's crabs by repeating the 14-16 hours of light cycle and 8-10 hours of dark cycles for 28 to 32 days at a water temperature of 23 to 28°C. Method for inducing early incubation of the mother's clam, comprising the step of forming an exoovum individual.

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