JPS6149931B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for cultivating coconut crabs, which cannot be cultured due to their spawning and growth habits.

The coconut crab is a type of terrestrial hermit crab, and is the largest type of crustacean that lives on land.
In Japan, it is a crustacean that inhabits the islands south of Yoron Island, especially Yonaguni Island and the subtropical regions of Southeast Asia. Its size is 10 to 15 cm long, and it is large.
They reach a length of 20 cm and weigh between 400 and 800 g, with the largest reaching several kilograms. Therefore, there is a lot of meat, and it is eaten in Okinawa and the South Sea Islands, and is extremely delicious.

However, the habit of coconut crabs is that during the spawning season, mother coconut crabs lay their eggs in the sea, and the hatchlings that hatched in the sea climb onto land from the sandy beach, where they grow by eating the leaves and fruits of terrestrial plants. They live in a hole. Therefore, it is extremely difficult to capture coconut crabs, and the absolute abundance of natural coconut crabs is small, and their habitats are often in places where people rarely visit, making it impossible to use them as general food. .

Furthermore, since ancient times, eating coconut crabs has sometimes caused symptoms such as diarrhea in humans, so although they are delicious, they are not widely used as a general food.

Recently, it has been discovered that the cause of the food toxicity of coconut crabs is that some of the leaves and fruits of the plants that coconut crabs eat while growing are toxic, and that these poison the bodies of the people who eat them rather than the bodies of the coconut crabs. There was found.

In view of the above-mentioned current situation, the present inventors have proposed that by allowing coconut crabs to lay eggs, hatch, and grow in an artificial environment, and by using food that is non-toxic to the human body, a large amount of coconut crabs that are not toxic to the human body can be produced, and many people can use it. He has spent many years researching methods for cultivating coconut crabs, with the aim of making it possible for people to enjoy their delicious taste and contribute greatly to society's dietary habits.

Therefore, the present inventor investigated and researched the spawning, hatching, growth conditions, and environment of coconut crabs, which have not been well known until now. discovered that coconut crabs can be cultivated if water and habitat conditions are kept constant.

The conditions for this are that the seawater temperature is around 27 to 29 degrees Celsius, that a sandbox is provided adjacent to the spawning hatchery, and that the space between the spawning hatchery and the sandbox is sloped toward the side of the spawning hatchery. It is necessary for coconut crabs to spawn, hatch, and grow by creating slopes with slopes, preferring calcareous holes for growth, and not allowing much food, rainwater, and other materials from the habitat to flow into the sandbox. Based on this discovery, artificial aquaculture is possible if this environment is provided, and the present invention has been completed.

In the present invention, a mother coconut crab is allowed to lay eggs in a seawater tank with a seawater temperature of around 27 to 29°C, and hatched and hatched in the same tank while being aerated and stirred.
The young were guided to a sandbox that was installed adjacent to the tank through a partition wall that sloped to the side of the tank. By growing the larvae into mature coconut crabs in a habitat with a large number of cave-like holes, it is possible to grow the eggs into mature coconut crabs in an artificially controlled environment without destroying most of the laid eggs. This method of cultivating coconut crabs has the advantage of being able to provide the market with a large quantity of coconut crabs that are completely free from edible toxicity by selecting the feed.

The size of the seawater tank used in the method of the present invention can be selected as appropriate depending on the site conditions, but in the case of cultivating 10,000 coconut crabs, for example, a rectangular tank of 10 m x 10 m x 10 m or a tank with an equivalent volume is made of concrete or the like. Form into a tank with an open top using a suitable material. This tank is equipped with a seawater circulation or agitation device to prevent seawater from becoming contaminated.
It is equipped with an oxygen (air) supply device that supplies the oxygen necessary for growing young.

The sandbox installed adjacent to this sea tank has a volume of about 2m x 2m x 2m on a scale of 10,000 fish.
Both bulkheads have a shape with a gentle slope along the seawater tank side so that the young fish can crawl up on their own, and their height is approximately equal to or slightly higher than the water level filled in the seawater tank. As a result, almost no sand in the sandbox flows into the seawater tank, and seawater slightly wets the sandbox, creating an extremely favorable environment for young coconut crabs to live in.

The nursery area for juveniles adjacent to the sandpit consists of a food supply station, a drinking water supply station, and a habitat.
Each of these locations may be located anywhere, but it is preferable to locate food and drinking water sources separate from the habitat, as it is convenient to capture mature coconut crabs.
Coconut crabs live in cave-like holes during the day, so it is inconvenient to capture them in caves. This is because they are active at night and it is more efficient to capture them when they come out to the feeding area.

The cave-like holes are made of calcareous material such as cement, rock, stone, etc. so that each hole can be easily entered. This is due to the habit of coconut crabs, which prefer to live in calcareous holes.

Coconut crabs generally take 1.5 to 2 years to grow from frying, so growing coconut crabs with different growth conditions in the same breeding ground may cause them to eat each other and reduce yield, so it is necessary to grow coconut crabs over a long period of time. It is preferable to provide a separate habitat for coconut crabs with the same structure and grow them separately there.

Coconut crabs are extremely sensitive to changes in temperature, and if they are grown in extremely high or low temperatures, they may die, so it is best to have a ceiling in the nursery area to provide shade and insulation. It can grow.

We will describe how to spawn, hatch, grow, and capture coconut crabs using the above-mentioned aquaculture equipment.

The spawning season for coconut crabs is determined by their habits from July 13th to 16th according to the lunar calendar.

Therefore, a mature spawning mother coconut crab is selected during this period, and the temperature of the seawater tank is adjusted to 27-29°C. However, generally in regions where the farms are located in the southwestern part of Japan, the water temperature is within the above temperature range even if it is natural at that time of year. If you live in a cold region, release the fish into a heated seawater tank using an appropriate method.

The spawning mother coconut crabs released into this seawater tank lay eggs on the tank wall. After spawning, the mother coconut crab crawls on its own through the partition between the tank wall and the sandbox and goes from the sandbox to the nursery area.

Eggs laid on the tank wall hatch in about 4 weeks in the seawater tank. At this time, in order to keep the seawater in the tank polluted and the dissolved oxygen level constant during hatching, the seawater is circulated, stirred, and air is introduced.

Coconut crabs that have hatched into young fish of a certain size crawl up the sloping wall between them and the sandbox on their own and go to the adjacent sandbox. They then pass through the sandbox and climb up the bulkhead of the nursery on their own to reach the nursery.

In the nursery area, there is food such as sugar, sweet potato, pineapple, etc. that is harmless to the human body, and a fresh water reservoir is placed to supply the necessary moisture. Coconut crabs habitually make dark holes made of limestone, so they make many easy-to-enter holes, and the young crawl into holes where there are no natives and make them their own homes. They hide in these homes during the day and use them as feeding grounds at night. They come out and eat and drink, repeating this process every day until they grow into a mature coconut crab weighing about 300 to 600 g in about 1.5 to 2 years.

Preferably, coconut crabs that have grown for about 6 months from the fry are transferred from the primary nursery to another secondary nursery to mature.

As described above, mature coconut crabs weighing about 500 to 800 g are captured at night when they appear at the feeding area.

In this way, the present invention involves analyzing the habits of coconut crabs and artificially setting the environment for farming them.
Moreover, since the feed is completely harmless to humans, mass farming and quality are the same.
Moreover, it is an extremely useful method that can supply large quantities of coconut crabs as general food without any fear of food poisoning.

Next, embodiments of the present invention will be described with reference to the drawings.

Example A concrete aquarium (3.5m x 3.5m x 1.5m) 1 is filled with seawater 2 at around 28°C, and one brooding mother coconut crab is released into it from July 13th to 16th of the lunar calendar. This mother coconut crab lays eggs on the tank wall during spawning season. Seawater is constantly circulated by a pump (not shown) through a seawater inlet 3 and a seawater outlet 4, and air is blown through an air inlet 5. If left in this environment for four weeks, the eggs will hatch and hatchlings about 0.05 cm in size will grow. 4
The young coconut crabs, which have reached the age of a week, crawl on their own up the sloping partition wall 6 between the sandbox and the adjacent sandbox, which has a height equal to the sea level, and reach the sandbox 7. The sandbox has the same width and height as the seawater tank, and is a 0.8m long concrete box filled with sand to the same height as the bulkhead. The young coconut crabs do not stay in this sandbox, but crawl up the next partition wall 8 on their own, pass through the feeding area 9, and reach the hole 11 in the nursery area 10.
Here, it enters a hole where there are no native coconut crabs and makes it its own home. Then, during the day, they hide in that residence, and at night they crawl out and go to the feeding area 12 and drinking hole 13, where they live for about two years. Two years later, we captured 2,857 adult coconut crabs (weighing about 600 g) that came out to the feeding area at night.

The growing area in this example is a three-hole cement brick (20cm x
40cm) at intervals, with the perforated side facing the feeding area, and on top of that, place three-hole cement bricks of the same shape to fill the spaced areas, with the non-opened area facing the feeding area. Arrange them in parallel. Stack this in 10 layers, 2
Three rows of similar tiers were built up with distance between the rows to create a growing area.

Furthermore, by covering the entire farm with a wire mesh and using shielding materials such as vinyl sheets on the ceiling to control the temperature of the cultured products, this will help the growth of the coconut crabs and prevent the coconut crabs from escaping from the farm. It is also possible to prevent this.

[Brief explanation of the drawing]

FIG. 1 is a slanted view of the aquaculture farm used for aquaculture according to the present invention. Figure 2 is an enlarged view of the nursery area of the aquaculture farm. 1: Seawater tank, 2: Seawater, 3: Seawater inlet, 4:
Seawater outlet, 5: air inlet, 6: bulkhead, 7: sandbox, 8: bulkhead, 9: feeding area, 10: nursery area, 11:
Hole, 12: Food storage area, 13: Watering hole.

Claims (1)

[Claims] 1 Mother coconut crabs are allowed to lay eggs in a seawater tank with a seawater temperature of around 27 to 29°C, and hatched into young in the same tank while being aerated and stirred. The young are guided to a sandpit set up through a partition wall, and the feeding and drinking holes are located through a partition wall that is slightly higher than the sand area adjacent to the sandbox, and a large number of cave-like holes made of calcareous material are provided. A method for cultivating coconut crabs, which is characterized by growing young coconut crabs in a field and turning them into mature coconut crabs.