JPH0226936B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method and a breeding apparatus for raising brooded lobsters during the cultivation process of lobsters.

[Background technology] The giant shrimp, which is native to Southeast Asia, is a freshwater shrimp that lives in rivers, and its shell is red with a bluish tinge.
Because it has elongated pincers that are nearly twice the length of its body, it is also commonly called Matsuba shrimp, and in recent years it has been attracting attention as an edible shrimp that can replace kuruma shrimp and flax shrimp.
In the past, such shrimps were imported and raised as pets for viewing, but this was an extremely difficult process that involved importing shrimp that were already in the form of shrimp and feeding and raising them in an aquarium. It is simple, and it has been thought that eggs can only hatch under natural conditions. However, the present inventor discovered that although giant shrimp are originally freshwater, they live near river mouths during the spawning season, and therefore require water containing a certain amount of salt at least during the period before and after the eggs hatch. We focused on creating conditions that are the same as in natural estuaries, at least during the period from the time when female giant shrimp incubate their eggs until the eggs hatch, pass through floating stage larvae (zoea), and turn into young shrimp.
By raising the shrimp in diluted seawater with fresh water, it has become possible to artificially hatch eggs of the shrimp, which was previously considered impossible. However, seawater is always required to hatch the eggs of the shrimp in this way, and when culturing shrimp in areas where seawater is difficult to obtain, it is necessary to incubate a large number of eggs in a relatively small aquarium. It is necessary to raise dried shrimp,
For this reason, inconveniences such as incubating shrimps fighting with each other in the tank and dropping the eggs may occur, resulting in a problem of poor yield.

[Object of the Invention] The present invention has been made in view of the above-mentioned points, and its purpose is to safely collect a plurality of brooding shrimp in a relatively narrow aquarium containing diluted seawater. The objective is to make it possible to easily farm giant shrimp with a small amount of seawater even in areas where seawater is difficult to obtain.

[Disclosure of the invention] The present invention dilutes seawater with fresh water to reduce the seawater content.
The aquarium containing diluted seawater with a concentration of 20% to 40% and a water temperature of 23°C to 32°C was divided into multiple compartments with a net, and one incubating female was isolated in each compartment. It is characterized by being bred. In the present invention, an aquarium containing such diluted seawater is divided into a plurality of sections with a net, and one female with eggs is kept in each section, so that a large number of eggs can be kept in a relatively small aquarium. Even if you raise several females, each female will not fight with each other and drop eggs.
Since it does not require a large amount of seawater, it is possible to easily cultivate giant shrimp even in areas where seawater is difficult to obtain. In addition, water can freely flow between each section separated by a net, so water circulation and purification, air injection, water temperature control using a heater, etc. are common to each section separated by a net. Compared to the case where the inside of the aquarium is partitioned with a glass plate or the like that does not allow water to pass through, the cost of managing water quality, water temperature, oxygen content, etc. can be reduced. The most suitable water temperature for egg hatching is 28℃, and the concentration of diluted seawater is 30% seawater.
The most favorable results were obtained when According to experiments conducted by the present inventor, it has been found that seawater is always necessary for eggs to hatch. It was also found that although seawater is necessary, in pure seawater, that is, 100% seawater, even if the eggs hatch, they die during the floating stage before they become young shrimp.

Hereinafter, the present invention will be described in further detail with reference to Examples. FIGS. 1 to 5 are diagrams showing a schematic configuration of a culture apparatus using the breeding method of the present invention. The one shown in Figure 1 is a freshwater aquarium, and in tank 1, which is about 1 tsubo in size, a harem is created by releasing parent giant shrimp in a ratio of 1 male to 5 to 8 females. ,
prepare for mating. The number of males does not necessarily need to be one, and when a plurality of females are included, the number of females may be increased according to the above ratio.
The water in this aquarium 1 is pumped up by a pump, filtered through a filter, and then returned to the aquarium 1. Also, air is constantly supplied to the water in the aquarium 1 to control the amount of oxygen in the water. I am trying not to reduce it. The temperature of the water in the water tank 1 is maintained within the range of 28°C to 30°C by a heater equipped with a temperature control device. If they are raised in this state while being fed, mating will occur and eggs will be laid between 6 and 20 hours after mating. The female shrimp protects the eggs while incubating them until they hatch and the larvae swim out. If a female with eggs is left in fresh water, she will drop the eggs, so the female is taken out of the freshwater tank 1 and released into the diluted seawater tank 2 as shown in Figure 2. At this time, in order to easily pull out the female with eggs from the tank 1, it is better that the tank 1 is not too wide.
It is most preferable to use The diluted seawater in tank 2 has a seawater content of 30% by volume. Natural seawater is used as seawater. The inventors have also attempted hatching experiments using saline water or artificial seawater, but in cases other than natural seawater, the eggs hatch, but they die at the larval stage and grow to the shape of a shrimp. turned out to be difficult. The water temperature in tank 2 is also maintained within the range of 28°C to 30°C, and air injection and water circulation and filtration by a pump are performed in the same manner as in tank 1. The aquarium 2 for diluted seawater is partitioned with a wire mesh 3, and the females with eggs are kept isolated one by one. The reason why females with eggs are isolated in this way is that, as mentioned above, if females with eggs are kept close together in a small space, they may fight and drop the eggs. According to the inventor's experiments, the area is 60cm x 30cm.
Glass aquarium 2 with a water depth of about 30 cm
When I used the trowel by dividing it into four equal parts with three pieces of wire mesh 3, there was hardly any egg dropping. The number of days it takes for the eggs to hatch after incubation varies depending on the water temperature; the higher the water temperature, the fewer days it takes for the eggs to hatch. According to experiments, the water temperature is 23
℃, 24℃, 26℃, 28℃, 30℃, and 32℃, the number of days required for hatching is 25 days, 23 days, 20 days, 17 days, 16 days, and 15 days after incubation, respectively.
It was hot in the sun. It is best to keep the water temperature as constant as possible from the time the female incubates the eggs until the eggs hatch, but if the temperature changes unavoidably,
It is preferable to set the temperature within the range of 28°C to 30°C.
Increasing the water temperature to 32°C will further shorten the number of days required for hatching, but this is not desirable because the energy cost required to maintain the water temperature is high. Raising the water temperature further than 32°C is also undesirable, as the water tends to become cloudy, and even if the eggs hatch, they die at the larval stage. water temperature
When the temperature is 28°C, the number of days from incubation to hatching is 17 days, so the female that has incubated the eggs two or three days before that time is further transferred to another aquarium 4 as shown in Figure 3. It is. In this aquarium 4, females that have incubated eggs and are about to hatch are kept in a breeding net 5 made of wire mesh. The water temperature and seawater content in tank 4 are the same as in tank 2, and the point that air is injected to prevent the oxygen in the water from decreasing is the same as in tank 2, but the water is circulated by a pump. No filtration. This is because when the eggs hatch, the larvae swim out, so if water is circulated and filtered using a pump, the larvae will be caught in the filter and die. When the water in the tank 4 becomes dirty, 20% to 30% of the water is replaced. Aquarium 4 is a round aquarium made of polyethylene or concrete with a capacity of 500 to 1000 liters.The reason for using a round aquarium is that compared to a square aquarium, there are no corners, so the water can stagnate. This is because it is difficult to clean and the water does not easily spoil. Since the larvae hatched from the eggs are much smaller than the mesh of the breeding net 5, they can freely move inside and outside the breeding net 5 and spread throughout the aquarium 4. In this state, the female shrimp is pulled up from the aquarium 4 along with the breeding net 5 and returned to the freshwater aquarium 1. After this,
For about 40 days, a bubbling device 6 etc. is inserted into the aquarium 4 as shown in Figure 4, air is injected and heat is kept using a heater, and the larvae are reared and managed until they become young shrimp. be. The water temperature and seawater content are the same as in FIG. In the early stage, within 10 days after hatching, the larvae themselves are small plankton, so it is necessary to feed them plankton even smaller than the larvae. In the inventor's experiments, it was found that it is preferable to hatch eggs of brine limp (Artemia: a type of shrimp) and provide them with fresh plankton. Brine shrimp eggs are commercially available from, for example, "Nippon Animal Pharmaceutical Co., Ltd.".
This brine shrimp is very easy to hatch and
The time required for hatching is said to be 24 to 48 hours when the water temperature is approximately 28°C in 3% saline or pure seawater. Brine shrimp must be fully hatched before being transferred to larvae. If you feed plankton that has been left for a long time after hatching,
During that time, the plankton grows larger, and the larvae of the giant shrimp are actually eaten. From about 10 days after hatching, feed minced clams and shrimp. The larvae before forming into young shrimp are swimming relatively above the tank 4. If you continue to raise them, some larvae will take the form of young shrimp in about 28 days after hatching, and about half (strongly) will take the form of young shrimp about 30 to 35 days after hatching. It turns and descends to the bottom of tank 4. Approximately 40 days after hatching, almost all of the shrimp take the form of young shrimp. Once they grow to this state, they will not die even if kept in fresh water, so they can be stocked in a large aquarium 7 as shown in FIG. 5 or elsewhere, and kept in fresh water. Breeding in this state is very easy. The eating habits of giant shrimp are omnivorous, and in the wild they eat anything, including aquatic worms, aquatic insects, small shellfish, shellfish, fish and animal meat, shellfish, algae, and soft leaves and stems of aquatic plants. . When aquaculture is carried out in the aquarium 7, etc., feed mixed feed such as trout, carp, sweetfish, sardine sardine, egg shells, etc. Regarding water temperature, since shrimp are originally from the tropics or subtropics, they are strong against high water temperatures but weak against low water temperatures.The water temperature at which they can normally live in is within the range of 18°C to 35°C, and the preferred water temperature is 25°C. to 32℃. Water temperature is 20℃
If the temperature drops below 14 degrees Celsius, they will stop eating, and if the temperature drops below 14 degrees Celsius, they will die. Onitenaga shrimp are 4 to 5 years old after hatching.
They grow into parent shrimp in a few months and lay eggs. The number of eggs laid by a single parent varies depending on the size, but on average it is around 20,000 to 30,000 eggs, and if the water temperature and other living conditions are good, they will spawn 5 to 7 times a year. After hatching, the size is
It grows to a length of 11 to 15 centimeters in about six months, and 30 to 30 centimeters in two years.
They grow to be 40 centimeters long, but for the domestic market it seems best to remove them from tank 7 and ship them when they are around 15 centimeters long.

[Effects of the Invention] As described above, the present invention dilutes seawater with fresh water so that the seawater content is 20% to 40%, and the water temperature is 23°C to 23°C.
The aquarium containing diluted seawater at 32°C was divided into multiple compartments with a net, and one female with eggs was placed in each compartment.
By raising each shrimp in isolation, we were able to artificially create a situation that closely matches the ecology of natural giant shrimp, where they live near the river mouth after incubation until the eggs hatch. This has made it possible to artificially incubate prawn eggs, which had previously been considered impossible. Moreover, an aquarium containing diluted seawater was divided into multiple compartments with a net, and each compartment was incubated with one egg. Because of this, even if a large number of females are kept in a relatively small aquarium, the females will not fight each other and drop their eggs, and they will not require too much seawater. This has the advantage that it is possible to easily cultivate giant shrimp even in areas where it is difficult to obtain seawater, and water can freely flow between the sections separated by nets. Circulation and purification of water, air injection, water temperature control using heaters, etc. can be performed in common for each compartment, and water quality, water temperature, oxygen content, etc. can be commonly managed for each compartment, reducing management costs. It also has the advantage that it can be reduced. Furthermore, in the breeding apparatus of the present invention, the water tank containing diluted seawater is equipped with an automatic water temperature control means for maintaining the water temperature within the range of 23°C to 32°C, so the water temperature is constantly monitored. Even without this method, it is possible to raise the incubating female at a water temperature suitable for hatching the eggs, and this has the effect of increasing the success rate of hatching the eggs.

[Brief explanation of drawings]

The drawings show an aquaculture device using the method of the present invention, and FIG. 1 is a schematic diagram of an aquarium used for mating and spawning of O. prawns, and FIG. A perspective view of an aquarium used during the period just before hatching; Figure 3 is a perspective view of an aquarium used during the hatching of Oonitenaga shrimp eggs;
FIG. 4 is a perspective view of an aquarium used for rearing hatched larvae, and FIG. 5 is a perspective view of an aquarium used for rearing young shrimp. 1, 2, 4, and 7 are water tanks, 3 is a wire mesh, 5 is a breeding net, and 6 is a bubbling device.

Claims (1)

[Claims] 1. Diluting seawater with fresh water to reduce the seawater content to 20% or more.
The aquarium containing diluted seawater with a water temperature of 23°C to 32°C is divided into multiple compartments with nets, and one incubating female is kept in isolation in each compartment. A method for raising incubating giant shrimp, which is characterized by: 2. The method for rearing incubating giant shrimp according to claim 1, wherein the seawater is natural seawater, and the seawater content is 30%. 3. The method for raising giant shrimp according to claim 1, wherein the water temperature is 28°C to 30°C. 4 Dilute seawater with fresh water to reduce the seawater content to 20% or more.
An aquarium containing 40% diluted seawater is provided with automatic water temperature control means for automatically maintaining the temperature of the diluted seawater within a range of 23°C to 32°C, and females with eggs can be raised in the aquarium. A breeding device for incubating giant shrimp, characterized by having a net arranged so as to form a plurality of compartments of the same size.