Breeding technology of grass carp

Grass carp belongs to the genus Grass Carp of the order Cypriniformes, family Cyprinidae, subfamily Yarosinae. The common names of grass carp include: grass carp, grass carp, oil grass carp, grass carp, white grass carp, grass carp, grass carp (Northeast), thick fish (Southern Shandong), sea carp (south), mixed carp, black herring, etc. Below, I will provide you with grass carp breeding technology, I hope it will be helpful to you! Key points of grass carp management

Spring

Broodstock cultivation

1. Timely improvement Improve the water quality of fish ponds, properly feed high-quality feed, and strengthen the cultivation of broodstock. The water quality of broodstock fish ponds after overwintering is generally aging and weakly acidic. Therefore, when the water temperature of the fish pond gradually rises and stabilizes above 13-15°C, the water quality of the fish pond should be treated. The specific methods are as follows:

(1) Replace 1/3 of the whole pond with fresh water;

(2) Appropriately lower the pond water level to facilitate a rapid increase in pond water temperature;

(3) When the weather is fine, turn on the aerator for 1 to 2 hours at noon;

(4) If necessary, use quicklime or microbial agents to improve the water quality of the fish pond.

2. Start feeding early to accelerate the gonad development of broodstock.

3. Patrol the pond frequently to avoid floating heads in the fish pond. The oxygen consumption of broodstock fish that are pregnant with eggs is relatively high. It is necessary to maintain a high dissolved oxygen content (4-5 mg/l) in the fish pond water quality, otherwise it will affect the development and maturity of broodstock fish. Once the pool water is hypoxic and the broodstock appears to have floating heads, it will affect the maturation and spawning of the broodstock, or even cause the broodstock to not lay eggs, seriously affecting the production throughout the year.

4. Strengthen flushing to promote the development and maturity of broodstock. When the water temperature is stable above 15°C, the water flow stimulation of the broodstock will be strengthened, which will help the development and maturity of the broodstock and help the mature broodstock to spawn smoothly.

5. Effectively control the occurrence of fish diseases and strictly control the dosage of pesticides in broodstock ponds. Some of the broodstock fish after overwintering may suffer from frostbite and saprolegnia. Dead and diseased fish must be removed in time to avoid contaminating the water quality. Spray hydrochloric acid (100g/mu.m) in the entire pond in a timely manner to prevent and treat saprolegnia. And strictly control the amount of pesticide applied in the broodstock pond. Excessive application of pesticides and excessive dosage will affect the mature spawning of broodstock, and even affect the quality of the fry hatched from spawning.

Adult fish breeding

1. Cloudy and mildewy weather often occurs in spring, the air pressure is low, and the water body is prone to lack of oxygen. The key points of water quality management at this time are: strengthen pond patrolling, Pay attention to the phenomenon of floating heads in fish ponds, and promptly turn on the aerator to increase oxygen; promptly replace the fish ponds and add fresh water; depending on the deterioration of the water quality in the fish ponds, sprinkle quicklime throughout the pond or apply microbial agents to improve the water quality and maintain good water quality in the fish ponds. environment.

2. After the beginning of spring, the water temperature in the fish pond gradually rises, and the fish begin to eat. At this time, they should start eating as early as possible and feed fresh and high-quality feed to ensure that the fish can start eating early and promote the recovery of their physical fitness. Enhance disease resistance, promote fish growth in a timely manner, and increase breeding output and efficiency.

3. Take measures to prevent and treat diseases. After overwintering, some fish may suffer from frostbite and saprolegnia, etc. The following methods can be adopted to prevent and control saprolegnia:

(1) Spray the whole pond with saprolegniacin (100g/mu.m);

(2) Spray the whole pond with gallnut juice to make the pond water concentration reach 4ppm.

Summer

1. Ponds should be cleaned frequently

Generally, ponds should be cleaned once every 1 to 2 years to remove 10-20 cm of bottom mud. While removing residual sludge, 75 kilograms of quicklime is used for disinfection per 667 square meters to completely eliminate harmful bacteria.

2. Disinfection of fish species

When stocking fish species, it is necessary to adhere to drug dipping and disinfection. Generally use 4% to 5% salt water to soak for 5 to 10 minutes, and the water temperature is 10 to 20°C.

3. Reasonable stocking

It should be achieved: there should be more fish varieties and sizes in the same pond. Generally, food fish account for 60% of the total stocking amount, and fat water fish account for 40%. Those that adopt intensive cultivation and have aerators should be placed appropriately densely, otherwise seedlings should be placed sparsely.

Generally, 800 to 1,000 fish are released for every 667 square meters of water surface.

4. Feeding science

When feeding and fertilizing, we must adhere to the four observations and four determinations, that is, feeding depends on the season, the weather, the water quality, and the fish eating situation. At the same time, timing, positioning, quality and quantity are achieved to ensure that the fish can eat enough, freshly and evenly.

5. Timely prevention and treatment of fish diseases

We must insist on: early prevention when there is no disease, early treatment when there is disease, and a combination of prevention and treatment. Quicklime is a good medicine to prevent fish diseases. It can prevent and treat diseases, regulate water quality, and promote fish growth. Generally, it can be used once every 15 to 20 days. About 15 kilograms per meter of water depth per 667 square meters can be used.

6. Prevention of floating heads

During the sultry thunderstorm weather in midsummer, fish tend to float and flood the pond. It is necessary to strengthen pond patrols at night. Once an abnormality is discovered, preventive measures to increase oxygenation should be taken immediately.

7. Precautions

It is prohibited to plant water peanuts and water chestnuts in the pond, and it is prohibited to soak trees. Environment and Disinfection of Grass Carp

Grass carp is the most susceptible to disease. Breeding pollution-free grass carp should have a dedicated breeding base and a certain scale, and there should be no pollution sources around the base. The breeding base should have sufficient water sources, good water quality, comply with the "Water Quality Standards for Freshwater Breeding Water for Pollution-free Food", smooth inlet and drainage, independent fish ponds, convenient transportation of fish, abundant feed resources, and good ecological and environmental conditions. High-quality grass carp species

To raise grass carp well, you must choose healthy and lively high-quality fish species. The parents of self-propagated fish species should come from qualified nationally recognized raw material farms, and the seeds should come from qualified nationally recognized raw material farms. It is cultivated without pollution, the quality meets relevant standards, and has excellent traits. It is best to breed and breed by yourself if the conditions are met. For example, fish species introduced from other places must pass the quarantine before they can be introduced. Fish must be disinfected before being put in. You can use chlorine dioxide at 20-40mg/L every 5-10 minutes, salt at 1-3% every 5-20 minutes, 8mg/L every 15-30 minutes, and high manganese. Soak and disinfect with potassium acid 10-20mg/L and other drugs every 15-30 minutes. The stocking ratio is 80:20, that is, the main grass carp accounts for 80%, and the supporting fish (silver carp, bighead carp, carp, crucian carp, etc.) accounts for 20%. Scientific feeding of grass carp

Grass carp mainly feeds on aquatic plants in natural waters. In pollution-free breeding in ponds, it is appropriate to use pellet feed with scientific proportions to reduce the pollution of water quality by residual bait and fully improve the utilization of bait. Rate. When producing grass carp pellet feed, a certain amount of grass carp meal should be added, which can not only reduce the cost of feed, but also meet the grass carp's demand for special nutrients such as cellulose and promote the growth of grass carp. The paddy grass fed with it should be tender, fresh and palatable. Cake and other types of bait must be mold-free, non-polluted, and non-toxic. After being crushed, soaked, cooked, etc., they should be made into bait that is easy for grass carp to eat and digest. When feeding bait, we must adhere to the feeding principles of timing, positioning, quality, and quantity. We must also determine the reasonable amount of feeding by observing the weather, water conditions, and the amount of fish eating. Fishing chemicals for feeding grass carp

Fishing chemicals are substances used to prevent and treat aquatic animal and plant diseases and insect pests. If used improperly, they can easily remain in the fish, causing the quality of the fish to fail, so be careful. use. Fishery drugs generally include fungicides, insecticides, water quality improvers, etc. Some traditional fishery drugs have been banned, such as chloramphenicol, furazole, sodium pentachlorophenate, malachite green, sulfathiazole, tylosin, 32 kinds of fishery drugs, such as olaquindox, sulfaamidine, and insecticides, cannot be used in aquaculture. Special attention should be paid when selecting fishery drugs. The industry standards promulgated by the Ministry of Agriculture list 26 types of fishery chemicals that should be used, such as dibromohydantoin, chlorine, bleaching powder, calcium chloride, and strong chlorine, and specify their uses and dosage. Please refer to the withdrawal period and precautions when using. Pay attention to grass feeding for grass carp

Grass carp begins to eat grass when the juvenile body length is 5 cm. Grass carp with a weight of more than 250 grams can eat 125 to 180 grams of grass per day. Therefore, when choosing forage to feed grass carp, you must pay attention to the following four levels:

1. Reduce the feeding of aquatic plants

According to experimental observations, grass carp eats 15 kilograms of terrestrial aquatic plants. You can grow 1 kilogram of meat, and only by eating 60 to 80 kilograms of aquatic plants can you grow 1 kilogram of meat.

Therefore, when there are sufficient sources of terrestrial aquatic plants, you can feed less or no aquatic plants.

2. Feed more fresh and tender forage

Fresh and tender forage is rich in nutrients, has less fiber, and is easy to digest. Grass carp eating fresh and tender forage can make grass carp grow faster and get less sick. It can reduce the amount of feeding, reduce breeding costs and improve economic benefits. Therefore, fresh and tender forage should be used as much as possible when feeding grass carp. The type of forage should be long-leaf green tender grass with parallel veins. It is not suitable to feed grass carp with reticular veins and lump-leaf forage that is anorectic. It is better to feed cultivated ryegrass, Sudan grass and other pastures and collected wild long-leaf young grasses. In normal times, the grass carp eating situation should also be observed. The grass carp likes to eat should be fed more to meet the growth and development needs of grass carp.

3. The feeding method must be appropriate

When feeding grass carp, feed it regularly, in sufficient amount, and evenly every day, and strive to spread the grass so that the fish can eat well. . The feeding amount should be adjusted according to specific conditions such as weather, water quality and fish activity. It is strictly prohibited to feed grass carp that has been stored for a long time or that has become moldy or spoiled to prevent grass carp from contracting diseases.

4. Feed different forage according to the diameter of the fish

Grass carp has a small diameter in the juvenile stage, so it cannot be fed with thick and hard forage. It is better to feed small duckweed. , sedge and other forages, or chop fresh long-leaf grass into pieces and feed them. Later, as the fish age and diameter gradually increase, they can transition to feeding conventional fresh and tender forage. High-yield breeding of grass carp

Generally, the traditional grass carp breeding model is one season a year, with artificial grass cutting and feeding, and the yield per mu is between 260 and 400 kilograms. This model has high labor intensity, low yield, and low efficiency. Liu Yuqing, a retired cadre from Liuqiao Village, Guhe Township, Gaotang County, Liaocheng City, used the old Laowan pit in front of his house that had been abandoned for many years to rebuild a 2.5-acre pond. He used artificial pellet feed to raise grass carp for two seasons a year, and achieved a yield of 1,960 kilograms per mu and a net profit of Benefits of 3,000 yuan. The technology is now introduced as follows.

(1) Pond reconstruction

Choose a pond with sufficient water source, convenient drainage and irrigation, no pollution, and micro-flowing water all year round for reconstruction. The water depth is between 1.5 and 2 meters.

(2) Pond disinfection

10 to 15 days before the fry are released, use 7 to 10 kg/mu of bleaching powder and clean the pond with water to disinfect, or use 75 kg/mu of quicklime water Sprinkle it all over the pool while it's hot.

(3) Fish pond stocking

The first season is around the Spring Festival, when the water temperature is 6 degrees Celsius. 600 grass carps are stocked per mu, with a specification of 350-400g/tail; 500 bream are properly mixed, with a specification of 200-250g/tail; 100 scale carps, a specification of 300-400g/tail; 20 bighead carp , the specification is 150-200g/tail; 100 carp, the specification is 100-150g/tail, to ensure that all can be put on the market before the Dragon Boat Festival. The second season starts after the Dragon Boat Festival, and all 600 grass carp fingerlings are released, with a size of 150 to 200 grams per fish. Before stocking, use 4% saline solution for immersion and disinfection for 0 to 15 minutes to prevent various bacterial diseases and saprolegnia.

(4) Feed selection and feeding method

Special pellet feed for grass carp with a protein content of 28% to 30% should be selected. The feeding method is based on the amount of grass and bream in the pond in the early stage of breeding. Calculated at 2% to 3% of the total weight of fish, scales, bighead carp, etc., it is changed to 5% to 6% in the later stage of breeding, and is fed twice a day.

(5) Daily management

For high-density intensive ponds, the main thing is to maintain good and stable water quality, focusing on preventing hypoxia and flooding of the pond.

① Add new water and maintain a small flow of water day and night. When encountering serious floating heads, increase the amount of water filling

② Patrol the pond early for light floating heads from 5 to 6 a.m. It starts to disappear after the sun rises between 7 and 8 o'clock, which is normal. The heavy floating head starts at 3 o'clock in the middle of the night. If no timely measures are taken, fish will be dead in the pond by 5 to 6 o'clock. Therefore, it is necessary to get up at 3 o'clock in the middle of the night to patrol the pond, especially in the two seasons of Xiaoman and Mangzhong where heavy floating heads are most likely to occur. If heavy floating heads are found, measures such as adding new water and turning on the aerator should be taken promptly to prevent pond flooding.

③ When turning on the aerator at the right time to cause the floating head to float, you can turn it on at 5 to 6 o'clock in the morning and stop it after the floating head phenomenon disappears at 8 to 9 o'clock. During the Xiaoman and Mangzhong seasons, in case of thunderstorms or muggy weather, the machine should be turned on at 12 o'clock in the middle of the night and shut down at 8 to 9 o'clock the next day.

(6) Disease prevention and control: Adhere to the policy of "prevention first, prevention is more important than cure". When patrolling the pond, if grass carp clusters are found at the water inlet and the fish body turns black, it is a sign of disease. At this time, pouring 1 mg/L bleaching powder on the entire pond for 2 to 3 days can stop the disease. The disease generally does not occur during the second season of breeding. Grass carp breeding technology

Pond requirements

The pond area should be 10 to 20 acres, the water depth should be 2 to 2.5 meters, and the silt thickness should not exceed 20 centimeters. Each 10 acres of pond is equipped with one aerator and one automatic feeding machine each with a power of 3 kilowatts;

Pond cleaning

Drain the pond water in winter and freeze and dry it for more than 20 days. Fifteen days before the fish fingerlings are stocked, 10 to 20 cm of water is introduced, and 150 kilograms of quicklime per mu is used to clear the pond for disinfection;

Fish fingerlings are stocked.

Before and after the Spring Festival, the stocking specification is 200 per mu. 300 grass carp species with a size of ~250 grams/tail, 300 crucian carp species with a size of 15-20 fish/kg, 50 silver carp species with a size of 5-6 fish/kg, and 10 bighead carp species. Before stocking, fish species should be soaked and disinfected in 5% salt water for 5 to 10 minutes;

Feeding

Mainly feed pellet feed, with a protein content of 28 to 32%. Add green feed. Feed feeding follows the principles of "coarse before and then concentrate after" and "four determinations and four observations". It is generally fed twice a day. It is appropriate to eat it within 2 hours and make the grass carp 80% full. After continuously feeding pellet feed for a period of time, the pellet feed should be stopped for 1 week, and raw grain feed should be fed during the interval. Pay attention to adding appropriate amounts of vitamins and other drugs to the feed to prevent grass carp from suffering from diseases such as hepatobiliary syndrome and causing a large number of deaths;

Water quality management

Proper use of aerators, 6 to 10 months On sunny days with no wind, turn on the machine and add oxygen for 2 hours every day from 1 to 3 pm, and add oxygen at the right time in the early morning; on continuous cloudy days, add oxygen in advance. Add new water to the pond in a timely manner, and adopt the method of "small discharge, small inlet, and multiple water changes" to gradually control the water quality. From June to September, add new water every 3 to 5 days, about 10 centimeters each time. Every 15 to 20 days, use 10 to 20 kilograms of quicklime to slurry the entire pool at a depth of 1 meter per mu of water surface. ;

Disease prevention and control

Adopt the method of feeding with "coarse at the front and fine at the back, fine and green" to control the occurrence of grass carp hepatobiliary syndrome. Common diseases of grass carp include red skin disease, gill rot, and enteritis. Treatment methods generally adopt a combination of oral administration and external application. The external application mainly uses disinfectants such as bleaching powder and chlorine dioxide for 3 days; oral administration uses Sanhuang powder. ?The effect of medicinal bait is better. For every 50 kilograms of fish body weight, use 0.3 kilograms of three yellow powders (50% rhubarb, 30% cork, and 20% skullcap, grind into powder and mix well) and mix it with the flour paste and mix it into the feed for feeding , used continuously for 3 to 5 days;

Timely fishing

Timely catching of large-sized adult fish and putting them on the market is an important measure for high-yield grass carp farming. The main purpose is to reduce the fish load of the pond water body. , Promote the rapid growth of pond fish in the later stage. Catching is usually done once at the end of July, in the early morning when the water temperature is low. ;