CATDOLL : CATDOLL: Can swimming crabs be farmed?

1. Can swimming crabs be farmed?

Swimming crabs can be farmed. They have strong adaptability to the environment, are relatively easy to manage during artificial breeding, and have a high survival rate. When breeding swimming crabs, the site should be built in the mid-tidal area with small waves, smooth tides, good seawater exchange, and easy drainage and irrigation. The pond height is about 2 meters, the water depth is 1.5 meters, and the transparency of the pool water is maintained at 30-40 centimeters.

Can swimming crabs be farmed? Swimming crabs can be farmed. They have strong adaptability to the environment, are relatively easy to manage during artificial breeding, and have a high survival rate. The breeding site should be built in a mid-tidal area with small waves, smooth tides, good seawater exchange, and easy drainage and irrigation to ensure that they are not harmed by typhoons, heavy rains, and factory sewage.

Pond requirements for swimming crabs: When breeding swimming crabs, the pond should be rectangular in shape, with an area of ​​3-10 acres, a pond height of about 2 meters, and a water depth of 1.5 meters. Before releasing the crab seedlings, sprinkle 10-15 grams of quicklime per square meter of the pond to ensure that it is sterile and harmless, and the transparency of the pond water is maintained at 30-40 cm.

The selection of swimming crab seedlings for swimming crab farming generally comes from natural and healthy crab seedlings, or artificially bred seedlings. When selecting crab seedlings, it is appropriate to choose those with uniform specifications, strong individuals, and sufficient vitality, and the soft shell rate should be less than 10%. The most suitable size of swimming crabs is 80 pieces/kg.

How to feed swimming crabs: When feeding swimming crabs, we must adhere to the principle of frequent meals and small amounts. The bait varieties should be mainly low-value fresh shellfish, miscellaneous fish, and shrimps. Pay attention to the freshness and palatability of the bait. In the early stage of breeding, you can add appropriate amounts of EM bacteria and other biological agents to decompose ammonia nitrogen to improve the water quality at the bottom of the pond.

Can swimming crabs be artificially bred? 1. Yes. Swimming crabs can be artificially bred. During the breeding process, sandy wasteland or saline-alkali land near the sea can be selected as breeding grounds, and breeding ponds can be built here. The area of ​​the pond should be controlled between 5 mu and 20 mu, and the water depth should be controlled at a height of one meter and a half to two meters. You can also place stones and tiles at the bottom of the pond to provide a hiding place for swimming crabs. 2. Selection of crab seedlings When breeding swimming crabs, you should also pay attention to the selection of crab seedlings. First, observe the appearance of the crab seedlings, and select crab seedlings with normal body shape, hard shell and complete body for breeding, or observe their body shape and select crab seedlings with strong physique, strong vitality and no scars for breeding. 3. Provide food In the process of breeding swimming crabs, you can provide it with feed three times a day. When preparing feed, you can use fresh shellfish, fish, shrimp and other foods, which need to be mashed before use. The feeding amount should be controlled at 15% of body weight. When feeding at noon, biological immune growth agents can be added to the feed to improve the immunity of swimming crabs. 4. Water quality control Swimming crabs are suitable for growing in a clear water environment. Therefore, during the breeding process, 20% of the water should be changed every day to keep the water clear. The water temperature can also be controlled at around 20 degrees and the salinity of seawater at 2% to allow the three-spotted crabs to grow healthily.

2. What are the survival skills of sea crabs?

The survival skills of sea crabs include feeding, regeneration of broken limbs and protective coloration.

Sea crabs, also known as swimming crabs, are omnivorous animals that like to eat shellfish, fresh fish, small shrimps, etc. They also eat young algae, dead marine animals and rotten aquatic plants. When they are caught by enemies and their lives are in danger, they will do everything they can to break off the caught legs and escape. After the legs are broken, they will regenerate from the original breakpoint, first growing a hemispherical giant, then growing into a stick, and finally growing into a new leg.

There are various pigment cells under the dermis of the swimming crab. When the pigment cells expand, the pigment diffuses and the body color becomes darker and thicker. When the pigment cells shrink, the body color becomes lighter and lighter. The expansion and contraction of pigment cells is caused by the stimulation of the secretion of the ductless glands in the eyestalk. The crab body on the sandy seabed is mostly light gray-green, and the crab body among the reefs or seaweed is mostly dark tea green.

prey

The three-spotted swimming crab is a fierce predator with a large appetite and strong digestive ability. It can cleverly prey on seaweed, snails and clams with hard shells, as well as fish, shrimps, crabs, etc. When the three-spotted swimming crab preys, its organs work closely together. The first pair of antennae have olfactory sensory hairs, which are used to identify food. It uses a pair of claws to capture food and brings it to its mouth together with the second pair of walking legs.

At this time, the mouthparts open automatically, and the food is first passed to the third maxillary foot, then to the mandibles to be crushed, and sent to the stomach through a very short esophagus. The food is then ground into a paste by the chewing apparatus and sent to the intestines for digestion and absorption. Examination of feces taken from the anus revealed that most aquatic vascular plant fragments can be digested.

The swimming crab is very greedy, and its stomach and intestines are often full or half full when the water temperature is above 10℃. When the water temperature is above 20℃, the feeding intensity of the swimming crab is even more amazing, and it can catch several snails in a night.

After eating, the three-spotted swimming crab stores the excess nutrients in the liver. The "soft-shell crab" that has just molted and during the winter needs the nutrients stored in the liver to maintain life. When the water temperature is below 10℃, it rarely eats. When it drops to 2-5℃, it will not die even if it does not eat for several months.

3. Why do the live swimming crabs I bought become hollow after being cooked?

Every time I see videos of beach hopping, I always see bloggers showing off their catches, and the thing they show off the most is the swimming crabs that everyone loves to eat. As a foodie, I like to eat swimming crabs very much. It may be because we are far away from the sea, so it is not easy to eat seafood, and it is very expensive. In our area, if you want to eat a lot of seafood at one time, the best way is to spend a certain amount of money to eat at a buffet. That is the most cost-effective way to eat. However, every time I go to a buffet, when I eat swimming crabs, I always can't eat them as delicious as in other food videos, which are full of crab roe and meat. The buffets we eat here are basically empty shells, with just a little bit of meat and no crab roe. They are very unpalatable. Later, I bought some frozen swimming crabs online and it was the same. They were empty when cooked.

Later, I consulted my friends in the south and found out that the swimming crabs we eat are called water crabs by the locals in coastal areas. They are very large and lively. After they are steamed, the water flows out as soon as the shells are peeled. After the water flows out, there is nothing to eat. There are many reasons for this situation. Here I will summarize 3 basic reasons for you:

Reason 1:

As for the reason of season, everyone knows that the best-tasting Yangcheng Lake hairy crabs are the most plump in mid-September and mid-October. The hairy crabs in this season have yellow roe and delicious meat. As a sea crab, swimming crabs are also seasonal. They are the most plump in March and October every year. Therefore, local people along the coast enjoy them best in this season. These two seasons are the early stage of swimming crabs preparing to spawn and the wintering. Therefore, swimming crabs are plump in these two times. The ones we eat may be caught and sold in other seasons. Therefore, there is no meat when they are cooked. They are just empty shells.

Reason 2: Crab inventory

We all know that our country has a fishing moratorium, which means that seafood cannot be caught during this season. The seafood we eat is either artificially farmed or frozen stock crabs. The stock crabs are either frozen, which makes them look not fresh, or the other way is to catch the swimming crabs and raise them temporarily, which ensures that they are fresh and can be sold at a good price. These swimming crabs are farmed in artificial seawater and rely on oxygen to sustain life. This way of breeding, not in a natural environment, will cause the activity of the swimming crabs to deteriorate. In the long run, although the swimming crabs appear to have not changed in size, they gradually become thinner due to insufficient food intake, and some of the protein in their bodies is also decomposed. Therefore, such swimming crabs are large and very heavy to hold. In fact, such swimming crabs have nothing to eat, and their stomachs are full of seawater, so if such swimming crabs are cooked, they will definitely be empty shells.

Reason 3: The swimming crabs are dying and have low activity

There are many such swimming crabs, and the reason for this is that many businesses, in exchange for more profits, feed these swimming crabs with oxygen and sea crystals. In such an environment, swimming crabs are easily infected by bacteria, and such infected crabs basically cannot swim, cannot prey, and can only consume their own nutrients, and slowly become water crabs. At this time, the merchants will freeze these swimming crabs and sell them to some remote areas. So we basically eat such swimming crabs in remote areas.

The above are the three reasons why the swimming crabs are empty shells after being bought and boiled. So we must pay attention when choosing swimming crabs. If we want to eat the best swimming crabs, first, we must choose the right season. Second, choose the ones with high activity. If you turn the swimming crab over, the whole body will move, which proves that it is very active. Another way is to press the abdomen of the crab with your hand to see if it is not very full and there is not much water coming out. If there is a lot of water coming out, it proves that the crab has no meat. Third, buy two-female crabs, that is, the kind with the navel under the white abdomen of the swimming crab between the round navel and the pointed navel, which is a two-female crab.

The swimming crabs I bought back were found to be empty after being cooked. This is because the swimming crabs are not mature yet, too young and too thin. Crab stalls usually have different grades of crabs, alive, dead, cheap, and 50% off. The expensive ones are definitely good. For the ones that you think are empty after being cooked, they should be cheap "water crabs". The ones that are very big are also very heavy, with soft shells and a belly full of water.

Swimming crab meat is tender and white, rich in protein, fat and various minerals. Both adults and children like to eat it. The mature swimming crab is 500g in size and 250g in general. The female crab is fully covered with red cream and is the most delicious. Why is N swimming crab empty after cooking? Swimming crab is an omnivorous animal. It grows by molting, growing one circle at a time.

Molting is the process of converting all nutrients in the body into soft shells for growth. When the shells are molted and hardened, the crab's appetite will increase significantly and its weight will double. This cycle repeats until the crab is fully mature. The crab you picked is empty after cooking, which means the crab has just molted and all nutrients have been used for growth. It is the beginning of a new round of growth and is not yet mature.

How do you choose a mature and plump swimming crab? Pinch the crab legs. If they are not soft but feel hard and firm, then they are mature and good crabs. If they are loose and water comes out when you pinch them, then they are not good and you should not buy them. Look at the crab legs. If you can see the meat and fat when you open them, then they are definitely good. If they are hollow inside, then they are too thin and have not grown up yet, so you should not buy them.

If you compare two swimming crabs, the heavier one is definitely fatter than the lighter one. In terms of color, choose the white belly of the swimming crab, not the porcelain white one, and choose the one with more red belly navel, the meat is definitely the fattest. In terms of price, the more expensive one is the best, which is always the key, you get what you pay for.

Finally, we should talk about eating swimming crabs in the right season, avoiding the middle period of the growth process of swimming crabs. It is definitely right to eat swimming crabs when they are mature and tender. Finally, you are always welcome to choose good swimming crabs. Female crabs are more delicious than male crabs.

1. The reason why crabs are transported and fed

Nowadays, many merchants who sell swimming crabs will loudly say that their swimming crabs are not oxygenated, which means that the crabs are fresher and the time from catching to selling is not long. After the crabs are caught, they are oxygenated to keep them fresh, so that the crabs can survive longer and are easier to sell. However, oxygenated crabs do not eat, so the meat inside the shell will naturally become hollow after being stored for a long time.

Crabs are farmed with artificial seawater. Now there is a new product for selling seafood - sea crystal. This kind of thing will create a sea surface-like environment when added to the water, ensuring that the fresh seafood is not dead. However, if the crab is stored in this environment for a long time, the meat is almost gone. It still looks like it is moving and it is heavy to pick up. However, when you get home and boil the lid, it is full of water, and it is still very salty without salt. This is the effect of sea crystal.

There is no best time to eat crabs themselves, they are not fat when they are caught, and if they are oxygenated and kept alive with sea crystals, then N will definitely be empty.

2. How to choose swimming crabs with fat canopies

Don't eat them often. The fattest season for swimming crabs is around the spring Qingming Festival to May Day, and around the 15th day of the eighth lunar month in autumn. The swimming crabs in these two seasons are the fattest and tenderest. Of course, you should eat these two seasons when you want to eat sea crabs. Swimming crabs in other seasons are not good, unless you go to a restaurant to eat those swimming crabs that are yellow all year round for some reason, but the price is also very high.

When choosing swimming crabs, pinch the second leg of the crab. The hind leg will recover quickly and feel like it is not moving, which means the crab is relatively fat.

Turning the swimming crab over, it can turn over quickly and is very active, unlike the oxygenated sea crabs which are always in a state of "exposing their legs and moving, but other areas are not easy to move".

Look at the junction of the crab's back cover. The higher and rounder the junction is, the fatter the crab is.

Choose the type of female crabs to buy. These crabs are usually very fat, probably because they cannot get pregnant. That is, the type with a navel between a round navel and a pointed navel. This type of swimming crab is usually a good buy, and each one is fat.

In fact, when exposed to high temperatures, the swimming crab will escape, so sometimes we only see its shell, but its meat is also in the bowl.

Now many vendors selling swimming crabs will loudly say that their swimming crabs are not oxygenated, which means that the crabs are fresh and the time from fishing to selling is not long. After the crabs are caught, they are oxygenated to keep them fresh, so that the crabs can survive longer and are easier to sell. However, oxygenated crabs do not eat, so the meat in the shell will naturally become hollow after being left for a long time.