CATDOLL : CATDOLL: Technical guidance for freshwater cage farming of rice field eels?

1. Technical guidance for freshwater cage farming of rice field eels?

The cage culture technology of eels has gradually formed a scale in some areas over time, mainly including: Hubei, Hunan, and Jiangxi provinces. At present, the most mature point of eel farming is cage culture technology, such as the previous rice field farming and cement pool farming. Although the eel cage technology has become large-scale, there are many problems in actual production. If these problems cannot be solved, it will eventually restrict the development of eels.

In the process of engaging in eel farming, in order to understand the current situation of eel cage farming from farmers, I have come into contact with many eel farmers, including those who tell the truth, those who tell lies, and those who tell half-truths. Among them, those who are willing to discuss with me several problems currently existing in cage farming are second to none. The development of the eel farming industry has been severely restricted.

The following is an overview of eel cage farming technology, which we hope will play a role in promoting the development of the eel farming industry.

Eel cage farming technology includes:

Eel fry, cage specifications, cage density, eel stocking density in the cage, aquatic plants, net hanging methods, water quality management, feeding techniques, mixed fish species and proportions, use of drugs, etc.

This is the pattern of several groups of eel cages, as follows:

Eel fry: Currently, eel fry are mainly wild, and the supply of artificially bred fry is small, which needs to be broken through.

Cage specifications: Currently there are 4 square meters, 5 square meters, and 6 square meters, among which the 4 square meter cage is the main one.

Cage density: Taking 4 square cages as an example, it is appropriate to stock 15-20 cages per acre. The cages should not be too close to each other, 0.5 meters is appropriate, and the distance between rows should be more than 2 meters to ensure the fluidity of the water and the ventilation of the cages.

Eel stocking density in cages: Generally, the stocking density of eels is about 3 jin per square meter, with more large ones and fewer small ones. However, many breeders believe that since the seedlings will be damaged anyway, putting more will not result in too few when they are taken. It is understood that the highest stocking density in Jiangxi is about 5 jin per square meter, or even higher. Too high a density can cause crowding stress to eels, resulting in "detoxification" disorders in internal organs such as the liver and intestines, and further induce metabolic disorders. This affects the eels' eating, growth, and morbidity.

Water plants:

At present, water peanut is the main crop, and water hyacinth is rarely used. The main problem of water peanut is insects. There are two types of pests that harm water peanuts: one is pests similar to mites, and the other is small insects.

1. Pests similar to mites. Generally, white spots are formed on the leaves of water peanuts, which eventually cause the water peanuts to wither and die. This type of damage is relatively rare, and breeders usually do not need to take precautions. Once discovered, they should be killed in time.

2. Insects. The speed of harming water peanuts is very fast. It usually takes only 3-5 days from discovery to the time when most of the water peanut leaves are eaten. Once the breeder finds a large number of holes in the leaves of water peanuts in individual cages, he should immediately kill them with drugs and spray them with a sprayer. Try not to spray into the water when spraying, and spray the leaves of water peanuts. This type of pest usually harms water peanuts in August every year, and some areas are earlier. Breeders must discover it in advance. Once such pests are found, it is best to spray again after the first application of pesticides, or spray once every 20 days or so throughout the prone month. The advantage of water peanuts is that they are not easy to rot. Even if they rot, they are leaves, which will not spoil the water quality and waste less food. Because water peanuts have a well-developed root system, food generally rarely sinks directly to the bottom. The disadvantage is that they are easy to breed insects and bloom and age. This can be controlled artificially.

Netting method: The one with bamboo sticks inserted directly can be used for about 3 years, and the one with iron wire and some bamboo sticks can be used for about 5 years. The former has a wide range of applications, while the latter is not suitable for areas with cement roads around. This method can be used for areas with many rats, and the effect of iron wire passing through mineral water bottles is better.

Water Quality Management:

Water quality management is divided into outside the cage and inside the cage, which is like a country and a home. Only when the water quality outside is good can the water quality inside the cage be guaranteed. How to regulate water? We all know that water is flowing, and it has to flow many times before it reaches its destination. Then it can be said that water is a kind of flowing "soil" and a kind of flowing "ore". People who have read Lin Wenhui's "Things about the Pond" probably know that the important properties of water bodies that have an important impact on ecology include: temperature, salinity, pH value, pE (oxidation-reduction potential), alkalinity, and hardness. Among them, temperature is a regional solar radiation property, and pE is the result of biological activity. The pH value is affected by both the water body itself and biological activity. The chemical formula of water is H2O, but water in nature is ever-changing and is mainly composed of eight ions: calcium, magnesium, potassium, sodium, carbonate, bicarbonate, sulfate, and hydrochloric acid. Among them, calcium, magnesium, potassium, and sodium are cations, and carbonate, bicarbonate, hydrochloride, and sulfate are anions. The difference between the current amount of cations and the current amount of anions determines the pH value in the water. Calcium and magnesium determine the hardness of the water, and carbonate and bicarbonate determine the total alkalinity of the water. It can be seen that water is no longer "invisible". If we want to regulate water, we must first know some of its properties to better help us manage the water quality of the pond.

Feeding technology:

Feeding techniques are divided into training feeding and daily feeding. If training feeding is done well, the opening rate will be high, at least the yield will not be very low. In the past, eels were fed with animal bait and plant bait, and the yield was not very high. However, with the emergence of eel feed, the yield of eels has increased significantly, but how much feed and fish should be fed, and what is the ratio. Many people do not have clear numbers, and generally choose to feed what eels like to eat, and the ratio of fish to feed is between 5:1 and 2.5:1. If fed in this way, the yield of eels is not very high. It is better to control the ratio of fish to feed at 2:1 to 1.5:1.

Mixed fish species and proportions:

The fish species raised in eel cage farming are mainly to help regulate water quality. Because the conditions of each pond are different, there is no fixed one. Here I give a reference data. Silver carp, yellow catfish, grass carp, silver carp, etc. are mainly raised. Silver carp is mainly used to regulate water quality and balance algae. There are 15 silver carps per mu, about 3 per catty, and 50 silver carps, about 3 per catty. 100 yellow catfish are placed per mu to increase economic value and reduce the waste of eel bait. 25 grass carps, about 3 per catty, and large ones can be put less, mainly to improve the utilization rate of the pond. 15 silver carps can effectively kill leeches in the water, especially in ponds with seedlings from the previous year.

Use of medication:

Because the amount of feed for artificially bred eels is relatively large, and most eels are wild, the environment of eels under high-density breeding conditions will be relatively harsh, and bacteria and viruses will multiply rapidly. Whether from the perspective of environmental issues or eels' physical tolerance and digestion problems, they need to be handled artificially, and at this time, drugs are needed to deal with them. How to use drugs reasonably is also a problem currently faced. For example, in the liver and gallbladder, the ingredients often used are glucuron-lactone and betaine, which are better than other drugs.

2. Fish farming technology?

1.

Stocking time selection: Fish should be released on sunny days when the temperature is not too low. Generally, the temperature should be between 2℃ and 5℃. At this stage, the fish scales are tight and the activity is small. It is not easy to injure the fish during fishing, transportation and stocking operations, which can reduce the morbidity and mortality of fish. It is easy to frostbite the fish on rainy days with low temperature or snowy, frozen and windy weather; when the temperature is too high, the fish scales are loose and the activity is large, which is easy to injure the fish during operation.

2.

Stocking of fish: Before stocking the fish, check whether the drugs have lost their effectiveness after pond cleaning. In early spring, the water temperature is low and the toxicity disappears slowly. Water should be taken in advance and test fish should be released. According to the stocking plan, individual size, density, and matching species and specifications, the fish that can be released at one time should not be released in batches, so that the fish can adapt to the environment, start eating early, and promote growth. At the same time, [Gold Iodine] should be used for drug disinfection when stocking fish.

3.

Feeding at the right time When the water temperature rises to 810℃, fish begin to eat, and the amount of food intake gradually increases with the increase of water temperature, so they should be fed in time. Feed once a day or every other day, and choose to feed at noon on a sunny day; as the water temperature continues to rise, the number of feedings can be increased to twice, that is, feeding once in the morning and once in the afternoon. Feeding should adhere to the principle of four determinations (timing, quality, positioning, and quantity), and the specific daily feeding amount should be flexibly controlled according to the weather, water temperature, and the feeding situation of fish. For grass carp weighing more than 1 jin, it is recommended to feed Da Beinong high-grade expanded feed 8103 in the early stage of feeding; for small grass carp mode, it is recommended to feed Da Beinong microecological juvenile fish special feed [Intestinal Liver Health], and the feeding rate is controlled at about 0.5%1%. This product is rich in nutrients and probiotics, which can quickly repair the fish intestines, restore the physique, and improve immunity.

3. Technology of breeding eels in cages?

1. Seedling selection

Judging from the breeding conditions in various places, the large-flowered eel seedlings are longer in shape, smaller in head, and have a uniform body shape. This variety has strong adaptability, grows rapidly, and has a high meat gain multiple. It grows faster and has a higher survival rate in cage farming.

2. Cage setting

The cage is open-topped, with specifications of 2m x 2m x 1.5m, and the cage is made of high-quality polyethylene knot-free mesh. When installed, the cage mouth is 50cm above the water surface, the cage body is 70-90cm into the water, and the bottom of the cage is more than 50cm from the bottom of the pond. According to the direction of the pond, the cages are connected in series longitudinally, 3m apart transversely, and neatly arranged.

3. Preparation before planting

Before stocking, the net cage should be placed in the water in advance, and then the water plants should be planted in the cage. The area of ​​the water plants should be more than 80% of the total area of ​​the net cage, and the water plants should be dense. In addition, according to the area of ​​the box, an appropriate amount of quicklime and bleaching powder should be sprayed for disinfection per cubic meter to kill pests and diseases in advance.

4. Stocking of seedlings

Generally, after April, when the water temperature is stable above 20℃ and there are continuous sunny days with no significant temperature difference between days, eels can be released. They are raised separately according to the same size, and the seedling density is maintained at about 1.25 kg/m2. On the day of release, vitamin C is sprayed in the cage to reduce the stress of the eel seedlings.

5. Domestication and feeding

Do not feed within two days after stocking, and start feeding earthworms on the third day. In the early stage of domestication, earthworms and fish paste are mainly used, and they are domesticated until they can normally eat whole fish paste. In the later stage, different nutrients should be fed according to the different growth stages of eels, mainly compound feed, and some earthworms, river snails, mealworms, etc. are appropriately fed. Generally, they are fed 1-2 times a day, at regular times and quantitatively.

6. Daily management

Check the cages every morning, noon and evening, observe the eels' activities and changes in water quality, remove dead eels in time, and promptly remove leftover bait, rotten aquatic plants in the cages and dirt outside the cages. Wash the cages frequently to maintain water exchange inside and outside the cages, and check the cages for damage or water rat infestation during cage washing, and deal with them in a timely manner to ensure the healthy growth of the eels.

4. What is the technology of breeding eel in cages?

Cage eel farming has many advantages, such as low fixed investment, low labor intensity, large or small scale, easy operation and management, fast fish growth, few diseases, flexible and convenient catching, etc. This method of eel farming is high-yield and efficient, and is the direction of development. It is also easy to intensively and scale farming. So, your nearly two acres of pond is fine, start with a small one. Let me briefly introduce:

1. Requirements for ponds: The requirements for ponds are not high, but not low either. The pond should be east-west oriented, sheltered from the wind and facing the sun, with a water depth of about 1.0 to 1.5 meters, good lighting conditions, and no industrial pollution. The ponds in front of the house or behind the house and the village center can be used. The cages are generally set in the sheltered and sunny part of the pond, with a water depth of 1.5 meters, and should be set near the residence for easy management.

2. About the net cage You have never seen a net cage. In fact, it is very simple. There are many ways to make it. Don't be rigid. You can make it yourself, which is cheap. Here is one: It is made of nylon line (polyethylene) knotless mesh. The size depends on the needs. It is generally a rectangular net cage with specifications of 3 meters × 2 meters × 1 meter or 10 meters × 3 meters × 1.2 meters. It is fixed with bamboo on all sides. It is 30-40 cm above the water surface. The mesh size is 10 mesh to 36 mesh. It is better to be small than large in production. Eels have the habit of drilling holes when they see them. If the mesh size is too large, even if the eels cannot drill out, they will not give up easily. As a result, they often get stuck in the head and affect their eating. At the same time, live bait is easy to escape from the mesh. In order to facilitate baiting, the net cage cover can use a larger mesh. The diameter of the upper and lower ropes of the net cage is 0.6 cm to 0.8 cm. There is a wide eaves extending 6 cm inward above the net cage mouth. The box body is 70 cm into the water and supported by piles.

3. Cage placement: Put about 30 cm thick river mud in the cage, or put the cage in water 5 to 7 days before the eels are put into the cage, so as to form a biofilm composed of filamentous algae on the mesh of the cage before the eels are put into the cage, which can prevent the eels from being injured by friction. The distribution area of ​​the cages should not exceed 60% of the total water surface of the pond. Arrange them in order according to the shape of the pond, and use bamboo frames between the cages to facilitate feeding and management. Put revolutionary grass in the cage, which accounts for about 95% of the cage area. The head of the water grass cannot be higher than the cage mouth to prevent the eels from escaping along the water grass.

4. Release of seedlings The eel seedlings are artificially bred seedlings or wild seedlings. They should be strong and free of external injuries, with bright colors. The general specifications are 25-100 grams per tail. 100 are released per square meter of water surface, and 150 small ones can be released, weighing about 2.5 kg to 5 kg. When stocking, they are washed and disinfected with 3% salt water for 10 minutes. The stocking time is April-May or July-August. They are released in boxes according to specifications, and each caged eel species is required to have the same specifications to avoid killing each other due to too large differences.

5. Daily management: First, water management. Eels like an environment with fertile water and sufficient dissolved oxygen. Generally, a water layer of 10 cm to 15 cm should be maintained. Change the water every 7 to 10 days in spring and every 3 to 5 days in summer. Keep the mesh unobstructed. If the mesh is blocked, the water inside and outside the cage cannot be exchanged in time, and the water inside the cage will quickly deteriorate, seriously affecting the feeding and growth of the eel. Second, feeding. After the eel is put into the cage, it cannot be fed within 3 days. After it adapts to the new environment, it can be fed once in the evening. The feed is mainly small fish, earthworms, snails, mussels, etc., with earthworms being the best. It can also be fed with artificial compound feeds such as water fleas, bean dregs, rapeseed cakes, fruits and vegetables. Feeding should be regular. Eels hide during the day and come out at night. It is appropriate to feed them at 6 to 8 pm. Eels eat vigorously when the water temperature is 15℃ to 32℃, and stop eating when it is below 10℃. The daily feeding amount is 6% to 8% of the eel's body weight. If the feeding is excessive, the remaining feed should be removed to keep the water clean. The feeding time is divided into two times at 8-9 am and 3-4 pm. The third is to prevent the eel from escaping. Check the interface of the cage frequently to see if it is firm and whether there is rodent damage. Fourth, during the breeding process, water peanuts are put into the cage, and its coverage accounts for about 80% of the cage area. This can not only purify the water quality, but also provide a hidden resting place for the eel, which is conducive to the growth of the eel. When transplanting water peanuts, it is best to remove the roots, wash them, and soak them in 5% salt water for about 10 minutes to prevent leeches and other harmful organisms from being brought into the box with the grass. Collect water peanuts regularly to prevent water peanuts from growing too vigorously and growing out of the box, causing eels to escape on rainy days.

6. Disease prevention and control Seedlings must be strictly disinfected before entering the box, especially from July to September when eels are prone to disease. Sprinkle the entire box with 1ppm bleach every 20 days, and isolate sick eels in time. If eels refuse to eat, reduce the amount of feeding in time to prevent enteritis caused by excessive feeding at one time. If the disease is found, take the right medicine in time to minimize the loss. 7. Winter management When the water temperature is below 15℃, eels basically stop eating and enter hibernation when it is below 10℃. Therefore, when the water temperature is suitable in early autumn, nutrition should be strengthened to enhance the physical fitness of eels in preparation for wintering energy consumption, that is, increase the amount of bait fed, and timely supplement liver-protecting and gallbladder-promoting, digestion-promoting drugs and multivitamins to enhance their body's ability to resist stress. When the water temperature drops to 15℃, preparations for wintering of eels should be made. Specific method: remove aquatic plants such as water hyacinth, spread 20 cm thick alkaline soil with more organic matter on the bottom of the cage, and then put the sterilized rice straw of the year into the cage, with a thickness of 40 to 50 cm. In this way, when the temperature is low, the eel will drill into the mud at the bottom of the net, and when the temperature rises, the eel will drill into the straw, or bask in the sun on the surface of the straw. During the wintering period, the water in the cage should be exchanged less to avoid freezing the eel due to too low water temperature. Also, what is the yield of eels? According to the amount of seedlings I mentioned above, if you have good skills, you can produce 40 kilograms of eels per square meter. The fish pond area is nearly two acres, and the investment is mainly cages, fry and feed. I haven't calculated it specifically, and it's not easy to calculate. The material of the cage is polyethylene mesh (also known as "sieve cloth" and "basket bottom cloth"), which generally costs 6-10 yuan per square meter and can be used for about 3 years. Feed cost, about, I mean about, there is also a problem with your management level. The feed costs about 200 yuan. The fry costs 1 yuan per fish. You can calculate it yourself. I estimate that one net can earn 500 yuan a year. You can put 60-70 net cages in your pond and earn more than 30,000 yuan a year. It's not very accurate.

5. What are the techniques for breeding eels in cages?

1. Seedling selection

Judging from the breeding conditions in various places, the large-flowered eel seedlings are longer in shape, smaller in head, and have a uniform body shape. This variety has strong adaptability, grows rapidly, and has a high meat gain multiple. It grows faster and has a higher survival rate in cage farming.

2. Cage setting

The cage is open-top, with specifications of 2m×2m×1.5m, and the cage body is made of high-quality polyethylene knot-free mesh. When installed, the cage mouth is 50cm above the water surface, the cage body is 70-90cm into the water, and the bottom of the cage is more than 50cm from the bottom of the pond. According to the direction of the pond, the cages are connected in series longitudinally, 3m apart transversely, and arranged neatly.

3. Preparation before planting

Before stocking, the net cage should be placed in the water in advance, and then the water plants should be planted in the cage. The area of ​​the water plants should be more than 80% of the total area of ​​the net cage, and the water plants should be dense. In addition, according to the area of ​​the box, an appropriate amount of quicklime and bleaching powder should be sprayed for disinfection per cubic meter to kill pests and diseases in advance.

4. Stocking of seedlings

Generally, after April, when the water temperature is stable above 20℃ and there are continuous sunny days with no significant temperature difference between days, eels can be released. They are raised separately according to the same size, and the seedling density is maintained at about 1.25 kg/m2. On the day of release, vitamin C is sprayed in the cage to reduce the stress of the eel seedlings.

5. Domestication and feeding

Do not feed within two days after stocking, and start feeding earthworms on the third day. In the early stage of domestication, earthworms and fish paste are mainly used, and they are domesticated until they can normally eat whole fish paste. In the later stage, different nutrients should be fed according to the different growth stages of eels, mainly compound feed, and some earthworms, river snails, mealworms, etc. are appropriately fed. Generally, they are fed 1-2 times a day, at regular times and quantitatively.

6. Daily management

Check the cages every morning, noon and evening, observe the eels' activities and changes in water quality, remove dead eels in time, and promptly remove leftover bait, rotten aquatic plants in the cages and dirt outside the cages. Wash the cages frequently to maintain water exchange inside and outside the cages, and check the cages for damage or water rat infestation during cage washing, and deal with them in a timely manner to ensure the healthy growth of the eels.

6. What is the technology of shrimp cage farming?

1. Making of cages

The net cages used for shrimp farming should not be too large. Generally, the specifications of 2 meters × 2 meters × 5 meters are the best. The nets should be made of polyethylene mesh. The nets for the wall of the box should be made of 48 meshes/square centimeter, and the nets for the bottom of the box should be made of 90 meshes/square centimeter.

The frame of the cage is made of wood or bamboo poles and is tied into an open floating cage. The cage mouth is 0.5 meters above the water surface. Bricks are used as sinkers at the four bottom corners of the cage to allow the cage wall net to droop naturally. Sinking stones are placed on both sides of the cage and tied to the cage frame to fix the position of the cage.

2. Seedling stocking

Fresh shrimps have the habit of cannibalizing each other. The size of shrimp fry in the same cage should be as consistent as possible to prevent the big ones from cannibalizing the small ones. The stocking density is 300-400 per cubic meter. The stocking density can be higher in waters with large water flow, and lower in waters with small water flow.

3. Feeding and management

Under the condition of artificial feeding of compound feed, green shrimps grow faster. After the shrimp fry are put into the box, plant baits such as soybean cake slurry (other cakes are also acceptable, such as peanut cake, rapeseed cake) are fed 2-3 times a day, and a small amount of animal feed (such as pig blood meal, silkworm pupa powder, etc.) is added. The calcium content in the feed should be appropriately increased to ensure the needs of the green shrimp's shell growth.

The daily feeding amount is 3%-5% of the weight of the shrimp in the cage. The amount of feeding should also be adjusted according to the feeding situation and temperature changes. Shrimp like to forage in the evening, so pay attention to feeding less during the day and more in the evening. Shrimp are evenly distributed in the cage, so the feeding should be evenly sprinkled.

Feed 3-4 times a day, wash the nets frequently to remove residual bait and algae to maintain good water exchange. Check for leaks regularly to prevent young shrimp from escaping and wild fish from entering.

4. Shrimp disease prevention and control

When farming freshwater shrimp in cages, the water exchange is fast, oxygen deficiency is not easy, and there are few predators, so shrimp diseases rarely occur. Molluscum parasitic disease (black gill disease) and white spot disease are the two main diseases.

7. Technology of cage culture of loach?

1. Loach seedlings are purchased from the nearest market and strictly screened before being put into the cages to ensure that the fish are disease-free, active, fat, and of uniform size. They are then soaked in 3% salt solution for 10 minutes before being put into the cages. The best time to put loach seedlings into the cages is from May to June 10 to 20. About 1,200 kilograms of loach are put into one acre, with a size of 5 grams. On average, about 30 kilograms of loach are put into each cage of 10 square meters.

2. The raw material of the cage is made of polyethylene, twisted wire mesh type; length × width × height is 6 meters × 4 meters × 1.8 meters, the cage frame is made of bamboo poles, each box needs 6 bamboo poles, 3 on each long side, directly fixed in the water; the underwater part of the cage is 1.5 meters, 0.3 meters above water, and the bottom of the cage is about 0.5 meters from the bottom of the pond. The cage is placed 15 days before the loach seedlings are released, so that algae are attached to the cage wall, and water peanuts and water hyacinths are transplanted into the cage, accounting for 1/3 of the cage area. On average, one cage is placed per mu of water surface.

3. Loach is an omnivorous fish. During the whole breeding process, the plant baits fed are mainly rice bran, vegetable cakes, wheat flour, potato residue, corn flour, and the animal baits are mealworms, snails, earthworms, maggots, small fish, etc. Its weight gain rate will be significantly improved, and the benefits will be better.

4. When breeding loaches in cages, a net should be added to cover the cage. The loach's unique intestinal breathing function causes the loach to frequently move up and down in the cage, swallowing air. In actual breeding production, it is easy to be pecked by water birds. This phenomenon was avoided by adding a net to cover the cage.

5. Patrol the pond every morning and evening to check whether the cages are damaged and whether the loaches are active normally. During the hot season from July to August, the water area covered by water hyacinths should account for 1/2 of the area of ​​the cages. Usually, remove excess water hyacinths in the cages to keep the area covered at about 1/3.

6. During the whole experiment, the net cages were basically not cleaned, which over-reliant on the intestinal respiration function of loaches, making them less likely to die from lack of oxygen. In fact, the net cages should be cleaned frequently to speed up the exchange of water inside and outside the cages, improve the water quality inside the cages, and be conducive to the growth of loaches.

7. After 5-8 months of breeding, the weight of loach can increase by about 4-6 times, and each cage produces 120-150 catties of loach on average, and the pond produces 4500-5000 catties per mu. At 13 yuan, the output value is 55,000-60,000 yuan, and the net income is more than 30,000 yuan.

Therefore, the economic benefits of cultivating loaches in ponds and cages are considerable and worthy of adoption by breeding enthusiasts.

8. Cage shrimp farming technology?

Method 1

1. When using cages to raise shrimp, we usually choose waters with sufficient sunlight, clean water quality, pH value between 7-8.5, water depth of more than 2m, less sludge, and flat bottom. Usually, it is unpolluted lakes, rivers or reservoirs. The better the environment, the more suitable it is for the growth of freshwater shrimp, and the better the breeding effect can be achieved.

2. Nets are generally made of polyethylene mesh and bamboo floats. Ropes are put around the bottom of the cage and the bamboo pieces and the lower end of the bamboo shoots are tightened and fixed to replace the sinker. The cage is suitable for building a rectangular size of 10*6.67*1.3m. This can reduce the production cost of the cage, increase water exchange and improve wind resistance for easy selection and fishing. The main factor affecting the water quality in the cage is the number of meshes in the cage.

3. A 1.3m thick bamboo piece should be tied to the bamboo frame of the cage every 2-3m. The lower end of the bamboo piece should be tied to the rope at the bottom of the cage, and the upper end of the bamboo piece should be tied to the rope at the top of the anti-escape net. The ropes should also be tied to the four corners of the anti-escape net, and then tightened with the bamboo tip and fixed to the upper part of the bamboo tip. A bamboo stake should be driven into each of the four corners close to the cage, with the lower part in the soil and the upper part out of the water. Then, the five bamboo stakes at the top of the hair tip fixed on the cage should be set and tied. Let the cage sink 0.9m underwater, leaving 0.4m above the water surface as an anti-escape net. Arrange 5 cages in a row, with a cage distance of 4-5m and a row distance of 5-6m.

4. The four corners of the anti-escape net are also tied with ropes and bamboo tips, and tied to the top of the bamboo tips. Tie a 1.3-meter-long thick bamboo piece to the bamboo frame every 2-3 meters. Tie the lower end of the bamboo piece to the rope of the bottom bar of the box, and tighten the upper end to the rope of the anti-escape net. Drive a bamboo stake close to each of the four corners of the box, with the lower end buried in the mud and the upper end exposed above the water. Then tie the five bamboo stakes at the top of the hair tip fixed on the net box with ropes. Make the net box sink 0.9 meters underwater and 0.4 meters above the water surface as an anti-escape net. The layout of the net cages is that every 5 net cages are arranged in a row, with a box distance of 4-5 meters and a row distance of 5-6 meters.

5. The feed for cage culture is similar to that for pond culture. However, cage culture shrimp needs to increase the number of daily feedings. Generally, feed twice a day, once at 8 am, the feeding amount is 1/3 of the daily feed amount, and once after 5 pm, the feeding amount is 2/3 of the daily feed amount.

6. Powdered bait is usually thrown on water plants, and its bait is thrown all over the box. The daily feed amount is 5%-8% of the weight of the shrimp in the box. After throwing the bait, carefully observe the shrimp's feeding situation. If the bait is eaten quickly, you can increase the amount of bait appropriately on the same day and the next day. In addition, when the temperature and climate are suitable and the weather is good, you can also increase the amount of feed appropriately.

7. Generally, freshwater shrimps are fed with compound feeds with a feed coefficient of 4.34-5.47, and the protein content of the compound feeds is required to be above 35%. Powdered feeds have a serious loss and a high feed coefficient. It should be advocated to use compound granular feeds to cultivate freshwater shrimps, which can not only maximize the feed utilization rate, but also increase the freshwater shrimp yield.

After the shrimps are cultured in the cage for one month, they must be protected from the invasion of dangerous animals such as river crabs, carp, eel, mandarin fish, wheatear fish, and striped fish. If found, they should be removed immediately. The general way to remove wild fish is to pull up the cage, gather the fish and shrimp in one corner of the cage, and then catch the wild fish or harmful fish by hand. Remove them once every half a month or so. Also pay attention to catching and killing water rats to prevent them from eating shrimps. Water birds can also cause damage, which can be driven away with a shotgun.

9. Sea urchin cage farming technology?

Sea urchin is a precious seafood. Farming sea urchin can meet market demand to a certain extent and protect wild sea urchin resources. The following are the general technical steps for sea urchin cage farming:

1. Site selection for cages: Choose a sea area suitable for sea urchin farming, where the water is clear and rich in nutrients, and avoid areas with storms and big waves.

2. Cage making: Choose a cage of appropriate size, usually rectangular or square, made of plastic or metal. The mesh size of the cage should be moderate to prevent the sea urchins from escaping.

3. Seedling selection: Choose healthy and strong sea urchin seedlings. Generally, the species of sea urchins cultured are purple sea urchins.

4. Adjustment of breeding environment: According to the preferences of sea urchins, adjust water temperature, salinity, water quality and other environmental factors to maintain a suitable growth environment.

5. Feed supply: Provide an appropriate amount of feed. Sea urchins mainly feed on seaweed, so you can choose seaweed suitable for sea urchins to feed.

6. Pest and disease control: Regularly check and remove debris in the cage to prevent the occurrence of pests and diseases.

7. Regular cleaning: Clean the cages regularly to keep the water clean.

8. Growth management: Control the stocking density according to the growth of sea urchins to avoid over-intensive stocking.

9. Harvesting and sales: According to the growth cycle of sea urchins, choose the appropriate time for harvesting to ensure the quality of sea urchins and sell them according to market demand.

Please note that the sea urchin farming process requires professional knowledge and technical support. It is recommended that before sea urchin farming, you should consult local agriculture, aquaculture departments or professionals to understand local farming conditions and specific requirements.

10. Which fish are suitable for freshwater farming in the north?

The following freshwater fish species are suitable for breeding in northern China

1. Carp Carp is one of the common freshwater fish in the north. They are often found in soft mud bottoms and waters with ditches, slopes, branches, rocks and other places where it is easy to hide or forage. Carp is an omnivorous fish and mainly feeds on vegetarian food. Fresh corn kernels and bran can be used as bait. Additives should mainly be fish meal, shrimp meal, silkworm meal, etc. with fishy smell.

2. White Stripe White Stripe is a primary freshwater fish. It has high requirements for water quality and reproduces quickly. This fish is similar in appearance to the horse mouth and the black bass. White Stripe likes fishy food and is a common fish at low altitudes. It likes to live in groups in the upper water layer of streams, lakes and reservoirs, and the depth of its habitat is generally 0 to 10 meters.

3. The scientific name of the Cockroach is Erythroculter ilishaeformis. It is large and slender. It is a large freshwater economic fish in the middle and upper layers. It moves quickly, is good at jumping, has a violent temperament, and is easily frightened. It grows rapidly and is a ferocious carnivorous fish that feeds mainly on live fish. The Cockroach can grow to the size of a meter and is very large.

4. Crucian carp is one of the common freshwater fish in the north. It grows in small rivers with stable water flow and abundant aquatic plants and plankton.