CATDOLL : CATDOLL: What are the farming techniques for breeding mud crabs in cement ponds?

What are the breeding techniques for breeding mud crabs in cement ponds?

Serrata mud crab, commonly known as mud crab, belongs to the class Crustacea, family Portunidae, and genus Scylla. It grows fast, has strong adaptability, delicious meat, and is rich in nutrition. It is an important economic crab in my country. In my country, mud crabs are abundant in coastal areas of Zhejiang, Fujian, Taiwan, Guangdong, Guangxi, and Hainan provinces south of the Yangtze River. The largest individual in the natural sea area can reach more than 1 kilogram. my country has a long history of artificial breeding of mud crabs. Especially in recent years, with the rapid development of marine aquaculture, the breeding area has continued to expand, and mud crabs have become one of the main species of marine aquaculture.

1. Breeding method

Because blue crabs have their own specific ecological habits, and the sea conditions, crab seedlings, bait supply, breeding technology management level and commercial crab sales channels are different in different places, there are many different ways to breed blue crabs. According to the breeding site, there are pond-type, fence-type, tile urn-type, wooden box-type and fish-e-type breeding. According to the management method, there are extensive breeding, semi-intensive breeding and intensive breeding. According to the stocking method, there are single breeding and mixed breeding. Mixed breeding can be divided into shrimp and crab mixed breeding, fish and crab mixed breeding, crab and shellfish mixed breeding, fish, shrimp and crab mixed breeding, and blue crab and various aquatic economic organisms mixed breeding.

2. Pond conditions and preparation before stocking

2.1 Conditions of the breeding pond

The crab pond should be built in a calm, freshwater-injected, pollution-free inner bay or on a sandy mudflat with a certain slope below the mid-tidal line. The water depth of the crab pond should be maintained at 0.8-1 meter at low tide. The area is generally 2-5 mu. If the area is too large, drainage and irrigation will be difficult, and a lot of manpower and material resources will be required. The bottom of the pond should be square or pot-shaped. If the pond water is shallow, circular trenches and cross trenches should be dug to facilitate the activities of blue crabs and create an environment that is cool in summer and warm in winter to facilitate the growth of blue crabs. Sand and mud are the best bottom materials, but mud and sand are also acceptable.

2.2 Preparation before stocking

Before stocking, the pond should be cleaned and disinfected. For old ponds, comprehensive cleaning should be carried out, including clearing the silt in the ditch, draining the pond, repairing the surrounding anti-escape facilities and collapsed dams, etc. 10 days before stocking, use 120kg of quicklime or 15kg of bleaching powder per mu to make a suspension and spray it all over the pond to kill harmful organisms in the pond.

3. Selection and stocking of crab seedlings

3.1 Source of crab seedlings

There are two sources of crab seedlings: one is the megalopa larvae obtained through artificial breeding, which are then cultivated into young crabs of suitable sizes; the other is the crab seedlings or young crabs caught from natural sea areas.

3.2 Selection of crab seedlings

Good quality seedlings have complete limbs, strong physique, no injuries, blue foot muscles, elastic muscles between limb joints, green carapace, strong vitality and not easy to catch; poor quality seedlings have dark green or green carapaces, some abdomens and walking legs are brown or rusty, and walking legs are defective. Crab seedlings with less than 3 walking legs, missing swimming legs and claws, thorns, hooks, sunburn or trauma are not suitable for seedlings. The parasitism of crab slaves will affect the growth and development of crabs, so they should be carefully removed before stocking.

What are the breeding techniques for mud crabs in cement ponds? Reasonable control must be exercised in terms of site selection, preparation, breeding techniques, disease prevention and control, etc. The optimal water temperature for mud crab breeding is 18~25℃. To breed mud crabs, the breeding pond needs to have an independent water supply and drainage system, and the pond water body should be close to a freshwater river.

Scylla serrata is cultured in cement pools, which can be indoors or outdoors. Cement pools are set up in the mid- and low-tide zones, and most of the pools are 150 to 350 square meters in area. The pools are dug 2.5 meters deep from the beach, covered with 0.5 meters of sand, with feeding platforms and sewage facilities on the side of the pools, and the top of the pools are covered with mesh to prevent the scylla serrata from escaping.

Farming methods Because blue crabs have their own specific ecological habits, and the sea conditions, crab seedlings, bait supply, farming technology management level and commercial crab sales channels in different places are different, there are many different ways to farm blue crabs. According to the breeding site, there are pond-type, fence-type, tile urn-type, wooden box-type and fish-e-type farming. According to the management method, there are extensive farming, semi-intensive farming and intensive farming. According to the stocking method, there are single farming and mixed farming. Mixed farming can be divided into shrimp and crab mixed farming, fish and crab mixed farming, crab and shellfish mixed farming, fish, shrimp and crab mixed farming, and blue crab and a variety of aquatic "

How to preserve hairy crabs so they don’t die?

As for creatures like hairy crabs, they must be eaten alive!

After the hairy crab dies, bacteria and harmful substances will quickly be produced in its body, which will damage human health. Therefore, dead hairy crabs cannot be eaten.

So, how should we store fresh hairy crabs?

Method 1: Place live crabs in water

This method is suitable for freshwater crabs such as river crabs and lake crabs (hairy crabs), and can keep crabs alive for several days. The specific method is: you may find a large area, such as a bathtub, sink or large basin, put the living freshwater crabs in it, and pour in some clean water. It should be noted that the water should not be too deep and cannot cover the crabs, otherwise the crabs may suffocate due to lack of oxygen. The water depth should be about half of the crab's body, so that the crab's eight legs can stand up and breathe on the water surface. In addition, do not cover the bathtub or large basin with a lid for fear that the crabs will crawl out, and then change the water several times a day, and throw some small fish and shrimp in for the big crabs to eat.

Method 2: Place live crabs in the refrigerator’s fresh-keeping room

After buying live hairy crabs, do not untie the crab ropes or wash them. Place the hairy crabs on a tray and put the tray in the refrigerator at a temperature of 5-8 degrees Celsius. Then, take a wet towel, about the same humidity as for wiping your face, and cover the back of the hairy crab with the towel. In this way, the hairy crabs can survive in the refrigerator for about a week.

By using this method, we can artificially create a state similar to "hibernation" for hairy crabs. Hairy crabs are in a low-temperature environment and are helped to be immobile, so their energy demand is very low and the loss caused is also very low. The wet towel on their backs provides them with the moisture they need to survive, so hairy crabs can survive in the refrigerator. However, although the energy consumption of hairy crabs in the refrigerator is very low, they will definitely lose energy in order to maintain their lives, so hairy crabs will inevitably become thinner and the taste will definitely not be as good as fresh hairy crabs.

Method 3: Put the cooked crab in the refrigerator

Many people may not finish eating the cooked crabs due to poor appetite or other reasons. If you want to save the crabs from lunch for the evening, you might as well wrap the cooked crabs with plastic wrap and put them in a cool and ventilated place to keep them fresh for 6-8 hours. If the weather is hot, it is best to put them in the refrigerator so that they can be kept until the evening, but not overnight. If you want to eat the crabs overnight or a few days later, you can cover the cooked crabs with plastic wrap and freeze them in the freezer together with the soup used to cook the crabs. This can better preserve the freshness of the crabs. However, it should be noted that the crabs and soup cannot be put in the refrigerator when they are still hot. Wait until they are completely cool before putting them in the freezer.

It is also necessary to remind you that the refrigerator is not a safe. If you store hairy crabs in the refrigerator using the above method, they may still die. If you find that the crabs are dead, you can't eat them. If the crabs that you can't finish eating are not stored properly, they may cause food poisoning, abdominal pain, diarrhea, and even gastroenteritis, which will bring great harm to your health.

Many people like to eat hairy crabs, but do you know that hairy crabs must be eaten alive? Dead hairy crabs will produce toxic substances and may cause food poisoning. So today, the editor of Xieshuge will share with you how to preserve hairy crabs so that they will not die.

Choose hairy crabs with vigor and vitality, prepare a 30-50 cm high plastic bucket/basin, put the hairy crabs in it without stacking; then add water to half the height of the hairy crabs' bodies, mainly to keep them moist, but not to bury them completely. Because you are unlikely to have oxygenation equipment, if the water is too deep, the hairy crabs will suffocate and die due to lack of oxygen. The bucket/basin does not need to be covered, check the hairy crabs every day, and eat the hairy crabs that are not vigorous enough in time. This method can be used to preserve the hairy crabs from Gucheng Lake, and the hairy crabs can be preserved for more than 5 days when the temperature is not high.

1. Preserve in a plastic bucket: First, place the fresh hairy crabs in a 30-50 cm high plastic bucket, then add an appropriate amount of clean water to the bucket, the water level should be enough to immerse half of the hairy crabs. If the water level is too deep, the crabs may suffocate due to lack of oxygen. It is recommended to check the crabs every day to see if they are active. If the crabs are not active enough, eat them in time. This method can be preserved for up to 4-5 days in an environment with low temperature.

2. Store in the refrigerator: Tie up the fresh hairy crabs with ropes, put them in the refrigerator, set the temperature to about 5°C, and then cover them with a wet towel. It is recommended to check the hairy crabs' eyes every day to see if they move. If not, eat them immediately. This low-temperature storage can be kept for up to 3 days.

3. Temporary storage: If you buy a large number of hairy crabs, you can put them in a bathtub or other large-volume containers at home, and fill them with just enough water to cover the hairy crabs. You can feed them some small shrimps every day. This method of storing hairy crabs generally lasts about 7 days, and the survival rate is relatively high.

It should be noted that if you do not plan to eat it immediately, it is recommended not to wash the large crab with water, otherwise the crab will die.

People who like to eat hairy crabs know that when buying hairy crabs, you must buy those that are fresh and full of vitality. Only such hairy crabs will be tender and have high nutritional value after being steamed. However, in life, people often buy hairy crabs but cannot eat them in time. So how should hairy crabs be preserved? Here I will teach you a few tips and tell you how to preserve hairy crabs.

1. How to preserve hairy crabs so they don’t die

1. Store hairy crabs in the refrigerator

If the number of hairy crabs purchased is not large and they can be eaten in about three days, their preservation is relatively simple: select hairy crabs that are vigorous, tie up their legs to reduce their physical consumption, then place them in the refrigerator's freezer, keep the temperature at 5-10 degrees, and cover with a wet towel for storage.

When eating every day, choose the ones that are not energetic enough to eat first, and the ones with full vitality can continue to be preserved. The way to distinguish is: touch the eyes of the hairy crab with your hand, if it does not react sensitively, eat it first.

2. Use plastic buckets/basins to store hairy crabs

Choose energetic hairy crabs, prepare a 30-50 cm high plastic bucket/basin, put the hairy crabs in it without stacking; then add water to half the height of the hairy crabs' bodies, mainly to keep them moist, but not to bury them completely. Because there is no oxygenation equipment, if the water is too deep, the crabs will suffocate and die due to lack of oxygen.

The bucket/basin does not need to be covered. Check the hairy crabs every day and eat those that are not energetic enough in time. Using this method to preserve Yangcheng Lake hairy crabs, the crabs can be preserved for more than 5 days when the temperature is not high.

3. Use temporary holding ponds to store hairy crabs

If you buy more Yangcheng Lake hairy crabs than you can eat in three to five days, the best way to preserve them is to use the bathtub as a temporary holding pool for the crabs, as the bathtub has smooth walls and the crabs cannot escape.

Gently pour the hairy crabs into the bathtub, fill it with water until it just covers the hairy crabs, so that the hairy crabs can stand up on their eight legs and breathe on the water surface, and add a small amount of small fish and shrimps according to the storage time and quantity.

Using this method to store hairy crabs, they can generally last for more than 7 days or longer, and the survival rate of Yangcheng Lake hairy crabs of good quality can reach more than 95%. In addition, check the hairy crabs every day and eat those that are not energetic enough in time.

2. How to keep hairy crabs fresh

After receiving the live hairy crabs, if you can't eat them all at once, you have to take care to preserve them. In September and October, it is best to put the tied hairy crabs directly into the refrigerator (note: not frozen) at a temperature of about 5 degrees Celsius and cover them with a wrung wet towel.

3. Notes

If you are not eating it right away, please do not wash it with water, otherwise the crab will die. If the indoor temperature does not exceed 15 degrees, there is no need to put it in the refrigerator. Under normal circumstances, it can be stored for 5-7 days, but if it is stored for too long, the crab will be thinner. It will not affect the taste if eaten within 3 days.

・You must choose fresh crabs; dead crabs cannot be eaten.

・Crabs are cold in nature and contain a lot of protein and cholesterol. People with weak constitutions and cold spleen and stomach should eat less.

・Do not eat with persimmons, pears, and eggplants.

・Also be careful to turn the crab over when steaming, don’t steam it upright.

・The gills, stomach, heart and intestines of the hairy crab cannot be eaten.

How to preserve hairy crabs without dying? Learn this little trick and the hairy crabs can be stored for a week without any problems!