What problems do you need to pay attention to in river crab breeding and fattening? Are there any ex

At present, the river crab is in the process of shedding its last shell and entering the fattening and rapid weight gain stage. At this time, feeding management should pay attention to the following points:

At this stage, although the water temperature has dropped, the storage of crabs, fish, and shrimp in the pond is at a high level, and the amount of dissolved oxygen consumed has surged. At the same time, the aquatic weeds in the pond enter the aging stage, and the severed limbs and rotten grass appear from time to time, which will also corrupt the water quality. Therefore, at this time, more attention should be paid to the problem of water quality, and a part of the aquatic weeds should be cut off in time and the residual grass should be removed, so as to effectively increase the space of the water body.

River crabs need to supplement a large amount of nutrients for shelling, fattening and rapid weight gain, especially the feeding of animal nutrients. To increase the feeding of small trash fish or marine fish, the compound should also increase the protein content, and also pay attention to the supplement of calcium nutrients. To splash the "shrimp crab grass savior" in time, supplement trace elements, and promote the growth of aquatic weeds to sprout, only to maintain the vitality of aquatic weeds, in order to make the river crab in the later stage of shelling full, a key to the shell.

Due to the influence of the 4 shells by the rainy season, the shelling and shelling are affected, so during the period of entering the 5 shells, the fattening period will go through more than 40 days, so it should be considered from the aspects of liver protection, promoting shelling, and supplementing trace elements.

The last shelling of river crabs is often the first concentrated shelling of female crabs, and about a week later, male crabs also start to shed their shells relatively intensively, which is a normal phenomenon. Farmers should patrol the pond 2-3 times a day, observe the feeding and activities of river crabs and observe the shelling of river crabs, if it is found that the river crabs have failed to shed their shells, they should carefully analyze the causes, or water quality problems, or caused by insufficient nutrition, etc., to find in time, eliminate in time, and take remedial measures in time to ensure that the river crabs take off the last shell and quickly fatten and gain weight, in order to increase production and improve breeding efficiency.

It is necessary to pay attention to the breeding process, but also to pay attention to the diseases of river crabs, but also to pay attention to the prevention of diseases, to pay attention to the breeding temperature, but also to pay attention to the cleanliness of the water source. When breeding, we must pay attention to the cleanliness of the water source, and we must regularly sterilize and disinfect, pay attention to the way of feeding, and pay attention to the matching of feed, which are some breeding experience.

To breed river crabs for fattening, first of all, you pay more attention to water. The oxygen content in the water should be increased enough, and the feed should be enough for them to eat. Also note the anomalies after the crabs have been shelled.

As long as there is a suitable breeding environment, such as clear water quality, abundant aquatic plants, weak light and reasonable water temperature, river crabs can grow normally.

Let's take a look at the conditions needed to breed river crabs and what to pay attention to.

First, the water source is sufficient, the water quality is fresh and pollution-free.

River crabs are very sensitive to water quality, and unqualified aquaculture water bodies are not good for raising crabs.

If the crab pond enters the polluted water, it will accumulate toxicity in the body of the river crab, affect the quality of the river crab, and be harmful to the human body when eaten; In the worst case, river crabs will die on a large scale, causing important economic losses.

Second, the construction of the living environment should be reasonable.

River crab breeding should not only have sufficient water sources, wide water depth, convenient drainage and irrigation, less sludge, fresh water quality, and abundant bait sources, but also build a good living environment for river crabs according to the characteristics of river crabs.

There should be a deep water area and a shallow water area, and the ratio of the area of the deep and shallow water area should be more than 3 1.

3. River crab seedlings should be free of pathogenic microorganisms and the introduction and use of diseased or pathogenic latent and unsterilized seedlings, when the conditions for the disease are ripe, it can cause an epidemic or pandemic of a certain crab disease.

When buying river crab seeds, they should be tested for pathogens and disinfected before putting them in the crab pond.

Practice has proved that most of the crab species introduced from the affected areas will get disease, and healthy crab species will rarely get sick.

Fourth, there should be a reasonable breeding model.

In the process of raising commercial crabs, some crab farmers will always raise a part of the baby crabs in the month, and at the end of the harvest, they catch mature crabs, and the remaining crabs continue to be reared, and the baby crabs are replenished in the following year.

For this breeding model, they not only do not see its harmfulness, but think that it is a good way to raise crabs, and as a result, the phenomenon of large crabs and enemies killing small crabs and soft shell crabs is very serious.

The correct approach is: the stocked river crab seedlings should ensure that the specifications are consistent, and the pond should be thoroughly cleaned and disinfected for a breeding cycle.

Fifth, the feed nutrition should be reasonable in the process of crab raising, some crab farmers do not feed enough bait, so that the growth of river crabs is slow, and the body is thin; Although some bait is more, the quality of the bait is poor and cannot meet its nutritional needs; Some of them are only fed with plant-based bait and do not feed animal-based bait, resulting in protein deficiency.

These incorrect practices make the river crab lack of nutrition, and its disease resistance is weak, so the probability of various diseases will be higher.

Therefore, in order to raise a good pool of crabs, it is necessary to raise and manage them according to the nutritional needs of river crabs, so that river crabs can grow healthily.

Aquatic weeds play an important role in river crab farming. Recently, when there are aquatic weeds floating on the water surface in the pond, they should be removed in time to avoid accidents that rotten grass will affect the water quality. If you are planted with Elo algae, the water temperature will begin to sprout and grow after the water temperature is reduced, and generally do not need to be taken care of, if you are planted with black algae, you can stop eating for 1-2 days to let the crab eat a part of the aquatic weeds or remove it, otherwise there will be rotten grass after the water temperature decreases in late October, and the rotting of aquatic weeds will greatly increase the nitrite in the water, which is easy to cause symptoms such as trembling of river crabs, and in severe cases, there will be mass death.

It has the characteristics of rooting and strengthening stems, decontamination and regreening, promoting the growth of aquatic weeds while stabilizing water quality, and has been successfully applied in river crab breeding in many places

Excessive levels of nitrite, ammonia nitrogen, and hydrogen sulfide can lead to river crab poisoning symptoms. In order to prevent the occurrence of this phenomenon, during this period of time, farmers should do a good job in preventing the decay of aquatic weeds, reducing feed residues, strengthening biological bottom modification, etc., and adopting scientific and effective detoxification measures to create a good ecological environment of river crabs is a problem that every farmer should pay attention to.

Many farmers will use itIt can complex heavy metal toxins, residual chlorine and pesticide residues in the water body, inhibit the generation of ammonia nitrogen, nitrite and other harmful substances, and repair bad water bodies; In addition, it is rich in nutrients such as small peptides, which can also reduce the stress damage of river crabs caused by changes in the external environment

At present, the most important thing is to do a good job in substrate management, because although the high temperature has passed, but the sultry days will still appear, the bottom quality is not good, it is easy to cause river crab poisoning, crabs with good physique can be postponed sales, and the pond mouth with poor physique should be listed as soon as possible.

Feed feeding should also be done well. In the near future, it is the fattening stage, not only to supplement the necessary nutrients, but also to pay attention to improving the physique of river crabs. Feeding should be done in moderation to avoid overfeeding affecting the substrate and water quality.

Nowadays, more and more farmers are applyingStaling, after use, the feeding speed is significantly accelerated, the substrate is stable, and the residual bait is less; In addition, Staling also has beneficial effects such as protecting the liver and gallbladder and improving intestinal immunity, escorting the successful listing of river crabs

Water quality environment, feed feeding, aquatic weed management and other factors are directly related to the smooth progress of river crab farming, despite the challenges, but we firmly believe that as long as we can master scientific and effective management measures, dare to pay, perseverance, will eventually achieve the final harvest.

Ponds should be built in a place with sufficient water sources and easy access and drainage, and closed before releasing crabsRationalCarry out pond disinfection and fertilization. When feeding, it is necessary to achieve timing, fixed-point, quantitative and qualitative.

1. Breeding methods

1) Generally, it is advisable to build ponds in places with convenient inlet and drainage, sufficient water sources and good water quality, and reasonably plant some aquatic plants in the ponds, such as water hyacinth, water floating lotus and other species, and at the same time take measures to prevent escape.

2) Before the seedlings are released, the pond needs to be cleaned and disinfected with quicklime, and it is also necessary to fertilize reasonably to cultivate algae and basic bait, and the transparency of the pond is generally 40-50cm.

3) It is necessary to select crabs with strong physique, active crawling and no injuries and diseases for stocking, and it is also necessary to reasonably control the breeding density.

4) When feeding, you can generally feed snails, mussels, livestock and poultry blood, water peanuts, bitter grass, cereals, bran, bran and other foods.

2. Precautions

1) If tadpoles and frog eggs are found in the pond, they need to be removed in time to avoid affecting the growth of crabs.

2) When feeding, it is necessary to achieve timing, fixed-point, quantitative and qualitative, and also to adjust the feeding amount reasonably according to the weather, for example, when the weather is fine, you can feed more appropriately, and you need to feed less appropriately on rainy days.

3) In the management, it is necessary to change the water reasonably frequently, and at the same time to keep the water level stable, the water can generally be changed once a week in the spring, and the water can be changed once every 3 days in the summer. It should be noted that if you encounter continuous high temperature weather, you can generally insist on changing the water every day.

In the process of meat crab breeding, we must pay attention to changing the water source in time to ensure the best water quality, and we must properly put a little small shrimp and other seafood to the meat crab to achieve the best nutrient absorption, pay attention to the correct posture, to achieve 3 4 hours of light time, and to do a good job of ventilation facilities, do a good job of sewage system.

Meat crabs have particularly high requirements for the environment, to prepare sufficient water sources, drainage and water intake, more convenient areas, to ensure that the water quality is good, there is no pollution, it is best to choose sand, clay, etc., it is best to choose a bucket of about 30 cm, and do not clean it when you just buy it, and you can't pile the crabs together.

It is necessary to pay attention to the selection of species, the situation of the pond, the quality of the water, the ratio of food, and the selection of crab seedlings is very important.

1. Fertilizer water is conducive to the reproduction of plankton, and natural bait is added to river crabs in the early stage.

2. Fertilizer and water can speed up the growth of aquatic weeds, and can also control the growth of moss.

3. After the algae are abundant, photosynthesis can improve the dissolved oxygen in the water body and promote the absorption and utilization rate of river crab bait.

4. Algae photosynthesis absorption reduces or even eliminates ammonia nitrogen and nitrite in the water body.

5. Algae can provide sufficient bait for snails and increase their egg capacity.

6. The algae-rich pond mouth has a stable water body, which is conducive to the success rate of river crab shelling.

7. If the crab is shelled, when there are insects in the water body can not be killed, the water of the crab pond is easy to mix, at this time, it is necessary to increase the dose of fertilizer water, cultivate algae, so that the insects have to eat, which can prevent the water body from becoming mixed.

8. In the later period, when the high temperature occurs, the crab pond algae phase is balanced, which can effectively inhibit the outbreak of cyanobacteria.

Crab breeding pond fertilization should be determined according to the water fat and thin situation, the water is generally thin to urea-based, about 5-10 catties per mu, add part of the phosphate fertilizer, about 2 catties per mu. The water fertility is moderate, and the top dressing is generally based on phosphate fertilizer, generally 1-2 catties per mu. In hot weather, urea or ammonium carbonate is not recommended.

Advantages: nutrients are released quickly in the water body, can reach a very high concentration in a short time, and the fertilizer and water speed is fast.

Disadvantages: First, the concentration of nutrients in a short period of time is too high, which can easily lead to excessive algae bloom in the water body and dense water. Second, if the nutrients cannot be quickly absorbed by algae, it is easy to cause the increase of ammonia nitrogen and nitrite in the water.

Third, the nutrient composition is single, and the fertilizer effect lasts for a short time. Fourth, improper fertilization can easily cause the proliferation of cyanobacteria and eugleniflagellates.

1. Pond preparation.

Breeding ponds should be selected in a place with abundant aquatic plants, clean and clear water quality, and full of sunshine, and the area of the pond should be determined according to the number of their own breeding. Generally in about 3-8 acres, the water should not be too deep, about m, there is a good drainage and irrigation system, the pond is best hard clay, to remove the thick silt at the bottom of the pond. Set up anti-escape equipment around the pond, and in order to reduce the incidence of disease in the breeding process, the pond should be cleaned and disinfected when stocking crab seedlings.

15 days before stocking, quicklime was used for sprinkling and disinfection of the whole pond, and the dosage per mu was about 75 kg. Quicklime can not only kill the germs in the pond, but also effectively increase the calcium ions in the water body and improve the bottom of the pond.

2. Select seeds and put seedlings.

When choosing crab species, you should choose excellent and pure varieties, and you can't choose miscellaneous crabs, crabs with injuries, or broken limbs. Crab species should be well-grown, well-developed, with complete appendages, no injuries and no differences in size. The purpose is to ensure the quality and survival rate of river crabs.

In order to let the crab seedlings have an excessive adaptation period, a temporary breeding area is set up in the pond, which accounts for about 1 5 of the entire pond. Pay attention to the stocking density, the density should be moderate, to ensure the normal growth and development of river crabs, and control the density at about 2,000 per mu. The stocking time is generally around the beginning of spring.

3. Feed feeding.

When breeding river crabs, it is necessary to feed some feed appropriately, because only the river crabs can not meet the growth and development of river crabs and achieve the purpose of high yield. After stocking crab fingerlings, when the water temperature in the pond reaches 11 degrees Celsius and above, it is necessary to manually sock and feed. When putting in the early concentrate, the middle coarse material, the late meat material is the main, in the spring key is good and the late season should be fed a small amount of paste bait, and in the summer it is necessary to feed the plant-type feed.

After August, it is necessary to start to increase the amount of animal meat, the main purpose is to promote the development of gonads, increase the weight of river crabs, and make their meat more delicious.

4. Water quality management.

Water quality has a very important impact on the growth and survival rate of river crabs, so we must do a good job in water quality management. When stocking crab fingerlings, it is necessary to ensure that there is a certain fertility in the water, and the fertility cannot be reduced, so water should be added at least once a week in the breeding. In addition, the water level should be deepened as the temperature rises, and the water level should be at least m in July, and the frequency of water changes should be increased or decreased when the temperature rises.

In summer, the water should be changed at least once a month from May to June, and at least once a week from July to August, and the frequency of water change can be gradually reduced when the temperature drops. Each time you change the water, you don't need to change the whole pool water, you can change about 30%, and you also need to splash quicklime regularly. It's about once every 15 days, and the effect was mentioned earlier.