JPS62259525A - Method and apparatus for arificial spawning and hatching of young eel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] A. Field of industrial application This invention is for the purpose of artificially producing whitebait eel in large quantities.
Using a pressurized sealed water tank, the compressor
We have installed an artificial rearing device equipped with an adjustable function, a high-pressure bubble generator, an automatic water temperature controller, a double hatch that allows the internal hatch to be opened and closed after closing the external hatch, an internal monitoring device for infrared feces, and other accessory equipment. This is a method and device devised for the purpose of raising parent eels, regulating water temperature, pressurizing and depressurizing them, and spawning and hatching them.

Conventional technologyThere are many unknowns about eel spawning and hatching.
Artificial spawning and hatching methods had not been realized.

In order to farm eels there, the eels spawn in the open ocean, and before they hatch and come back up the river, the young eels are caught at sea, or they are imported from foreign countries and farmed. The problems that the invention aims to solve include the problems with eel spawning and hatching.
Strong water pressure is required because they only spawn in deep water, around 150 meters deep.

■ As they are nocturnal, they need adequate darkness.

■ It is essential to maintain a stable water temperature of around 13 degrees Celsius.For this reason, in temperate regions, water temperatures tend to be low.
In the fall, they descend to the sea and migrate to warmer waters, spawning the following spring.
The hatched fry spend the winter at a suitable temperature and then return to rivers in early summer.

■ Being cowardly and needing a place to hide or hide.

■Do not spawn or hatch unless it is in salt water.

The ecology and habits mentioned above are mainly mentioned.

2. Means for Solving the Problem In order to satisfy the above condition (■), the present invention uses the sealed iron or other pressurized sealed water tank mentioned in Factor 1, and uses the compressor with automatic pressure adjustment function shown in Figure 14 to apply pressure. A high-pressure bubble generator with an automatic adjustment function shown in FIG. 9 is used to pressurize and supplement oxygen. To administer the feed, use the double hatch shown in Figure 2. After opening the upper hatch and adding the feed, use a structure that allows for opening/closing operations and air pressure adjustment. To prevent contamination, a strong wire mesh bait basket (Fig. 7) with around 5 meshes is installed.

For ■, monitoring and IL detection are required, so a red Tato line that can reach the deep sea is used, and a red Tato line illumination device and a red Tato line photosensitive camera or an infrared photosensitive television camera are used for this purpose. 8 to the extent that it does not irritate the eels, ensuring adequate darkness and monitoring and observation.

■In order to maintain an appropriate temperature throughout the year, we have installed an automatic water temperature controller with a thermostat that can be used for both high and low temperatures.
It is desirable to use Figure 12, preferably indoors.

In order to satisfy the condition of
The problem can be solved by laying the floor down by centimeters.

Problem (2) can be solved by first adding a small amount of fresh water and then gradually injecting irrigation water from the water inlet shown in Figure 5 to bring the salt concentration to the same level as the irrigation water.

E. Example In this invention, first, as shown in the drawings, a box-shaped or cylindrical shape made of iron or other material with a flat bottom, length, width, and height, which can sufficiently withstand pressurization up to 20 atmospheres as shown in FIG. But, l!
Prepare a pressurized sealed water tank with a diameter of 3 to 4 meters and a volume of about 18 to 36 cubic meters, install a safety valve that operates at 20 atm, a pressure gauge in Figure 3, and a pressure gauge in Figure 13, and fill it with sand through the hatch in Figure 6. Lay it out to a thickness of about 20 centimeters, fill it with fresh water shallowly from the water inlet shown in Figure 5, and place 4- to 6-year-old parent eels, 3 females and 1 male, on a sub-stand, and collect about 100 eels per square meter (Figure 6). Insert it through the hatch, close the hatch, and turn on the 100 watt pressure-resistant red Tato wire bulb shown in Figure 8.

Next, over a period of three days, fresh water was gradually drained from the upper drainage port in FIG. 11 while irrigation water was injected, and oxygen was continued to be supplied using the high-pressure bubble generator shown in FIG. 9. At the same time, use the compressor shown in Figure 14 to gradually increase the pressure until it reaches 1 atm, use the automatic water temperature controller shown in Figure 12 to set the water temperature to 13 degrees Celsius, and feed the food. 2. Feed the eel with the usual mixed feed as appropriate using the double hatch shown in Figure 2.

The animals are kept in this state for about 30 to 40 days while being monitored and observed using the infrared internal monitoring device shown in Figure 8.

At first, they move around actively and eat food well, but when they reach 30
After about a day, the food suddenly becomes difficult to eat and the ribs become sluggish, so if this continues for about 3 days, set the water temperature controller in Figure 12 to 12 degrees Celsius, and then within about an hour, The compressor in Figure 14 suddenly pressurizes -air to around 15 atm, and at the same time the infrared illumination in Figure 8 dims to near the visible limit (approximately 10 to 20 watts), and after that, there is little food. I only do it.

Until then, if you continue to keep an eye on the chickens and keep raising them for about a month, eggs will start to be laid at that time, so when you see that a considerable number of eggs have been laid, add a little powdered egg yolk. Then, the pressure was gradually increased to 18 atm over 42 hours, and after 3 hours, the yolk powder was added little by little at the same time while continuing to reduce the pressure until it reached 32 atm over about 12 days. Continue administering. (around this time) When the pressure reached 3.2 atmospheres on the 12th day, -0.
The pressure was reduced to 8 atmospheres, the illuminance of the red Tato line lighting equipment was increased to 100 watts, and the water temperature was set to 13 degrees Celsius.

In that state, the pressure was reduced to normal pressure for 72 hours, and the pressure was reduced to normal pressure for 8 hours. After starvation for another 4 days,
Gradually drain the water through the drain hole with a strong strainer of about 0 mesh, without getting the eel fry in it, and when the water level reaches about 1 meter from the bottom, drain the drain hole on the lower side without wire mesh, Figure 10. Either open the tank and drain the eel fry, or open the horizontal hatch shown in Figure 6 and take out the eel fry, clean the inside of the tank, and transfer the taken out fry to a regular aquarium to begin breeding.

EFFECTS OF THE INVENTION ■ The realization of artificial production is expected to prevent the decline in the natural eel population due to overfishing of whitebait eels.

■ Artificial production is expected to alleviate the difficulty faced by eel farmers in manning whitebait eels and the instability of market prices.

■ By enabling year-round production, it is expected that the effective use of existing aquaculture facilities will be promoted.

■ It helps in the effective use of marine resources.

The above effects are expected.

[Brief explanation of drawings]

The drawings are perspective views including perspective views of the present invention. 1 Pressurized sealed water tank. 2 With atmospheric pressure adjustment function,
Double hatch that allows you to open and close the internal hatch after closing the external hatch. 3 Safety valve. 4 Exhaust port. ” I8 Mizuguchi. 6 Hatsuchi 7
Bait receiving basket (5 mesh, 8 strong, front and rear made with internal monitoring using infrared lighting). Place. 9 Automatic adjustment I! High-pressure bubbles with 10 drain ports. generator.

Claims (2)

[Claims] (1) Artificial spawning method for whitebait eel. (2) Artificial spawning equipment for whitebait eel.