CATDOLL : CATDOLL: How to raise silver carp in cement pond

Yes. 1. Fish pond selection. The fish pond should be well ventilated and sunny, with sufficient water source, an area of ​​1 to 5 mu, a water depth of 1 to 1.5 meters, and some water lilies or water peanuts should be planted around it. It should be surrounded by nets in the lower places, which can prevent the escape of mullet and provide concealment and shade, creating a good ecological environment, which is conducive to the growth of mullet. 2. Pond cleaning and disinfection. After the fish pond is selected, drain the pond water first, use 140 kg to 150 kg of quicklime per 667 square meters to dissolve water, evenly sprinkle the whole pond, and use rakes and other tools to turn over the silt for full disinfection. One week before the stocking of mullet, fill the pond water to a depth of 1 meter, and apply appropriate basal fertilizer to improve the water quality. 3. Fish stocking. There are generally two sources of fish, one is wild and the other is artificially bred. But no matter which source of fish, they must be screened before being put into the pond. The fish with basically the same specifications should be bathed in 3% to 5% salt water for 5 to 10 minutes, and then put into the same fish pond. The stocking density depends on the water source, drainage conditions, and the source of bait fish. Under normal circumstances, for fish species 3 cm to 5 cm long, 6,000 to 10,000 are stocked in 667 square meters; for fish species 10 cm to 15 cm long, 4,000 to 6,000 are stocked; for fish species around 20 cm, about 2,000 are stocked. If the water source and drainage conditions are good and the source of bait fish is sufficient, the stocking density can be appropriately increased. 4. Feeding Artificial intensive black carp mainly uses low-value fresh small fish and shrimp as the main bait. Because wild or some artificially bred fish species eat live bait, the fish species should be stopped from being fed for one or two days after being put into the pond, and then an appropriate amount of dead bait should be fed around the pond every morning for domestication, and then gradually moved to one place in the pond for feeding. After the fish get used to eating dead bait, they should be fed once a day at 9 am and 4 pm, with the daily feeding amount being 5% to 10% of the fish's body weight, and should be flexibly controlled according to the weather, water temperature, growth, feeding, etc. 5. Daily management Black carp is not prone to disease in natural water bodies or under rare breeding conditions, but under artificial intensive breeding, if improper prevention and control is used, fish diseases will break out, causing serious economic losses. From the author's practice over the past few years, common diseases of mullet include saprolegniasis, rotten skin disease, ascites disease, gill rot disease, etc. If the prevention and control measures are appropriate, the fish will rarely or not get sick. Therefore, in the process of mullet breeding, water quality, fish conditions, salvage of residual bait, and prevention of escape should be checked frequently. If abnormal conditions are found, they should be dealt with in a timely manner. 6. Catch the big ones and keep the small ones, and put them on the market in time. Because mullet is a ferocious carnivorous fish, it will kill each other when there is insufficient bait, so it is necessary to catch the big ones and keep the small ones once every month or so. If the size difference is large and the number is large, they can be divided into other fish ponds or cages of the same size. When the market price is good, the adult fish that have reached the commercial size can be put on the market for sale. In this way, they can be sold at a good price and are conducive to the growth of small-sized fish.

1. Ecological habits

1. Food habits

Bighead carp's food is the plankton that grows in large quantities in the water. Its gill rakers are slender and closely arranged, but they have no bony bridges and no sieve membranes, so they can filter water quickly and have a greater ability to filter zooplankton. The main components of its food are rotifers, cladocerans of crustaceans, and a variety of algae. In terms of individual numbers, algae often outnumber animal food. But in terms of volume, animal food still accounts for the majority. From the feeding characteristics of bighead carp, it can be seen that it is a species that continuously ingests food. During the growing season of plankton, as long as its mouth is constantly opened and closed, food will continue to enter its mouth with water. From its feeding characteristics, it can also be seen that it is a mid-to-upper layer type. The intestinal length of bighead carp is generally about 5 times the body length.

2. Growth

The growth rate of bighead carp in the Yangtze River is faster than that in the Pearl River because, although the temperature-optimal period in the Pearl River is two months longer than that in the Yangtze River, the average biomass of plankton is significantly less than that in the Yangtze River. In artificially fertilized ponds, the growth of bighead carp varies greatly depending on the climate of each region and the abundance of biological food in the water.

3. Reproduction

Under natural conditions, the gonads of bighead carp, like other domestic fish, can develop in still water, but the maturation of eggs requires ecological conditions such as river water environment and rising water levels. In the main and tributary rivers of the Yangtze River, from late April to early July each year, when rainfall in the basin converges on the main stream, causing the water level to rise and the water temperature to reach 18°C, the gonads of the parent fish mature rapidly during the upstream process, and they turn from stage IV to stage V, i.e. spawning and fertilization. After the eggs are fertilized, they drift downstream and develop, and hatch into fry.

According to the survey, the age of maturity of bighead carp is 3-4 years in the Pearl River Basin and 4-5 years in the Yangtze River Basin. Bighead carp has a large egg-carrying capacity, with a maturity coefficient of about 20% and a relative egg-carrying capacity of 110-160 eggs/g body weight. The absolute egg-carrying capacity increases with the increase of body weight, forming a positive correlation.

2. Artificial breeding

1. Broodstock selection

No matter whether it is farmed or naturally grown, as long as it reaches sexual maturity, is large, grows well and has no injuries, it can be used as broodstock. Male fish have several fins in front of the pectoral fins with knife-like edges on the upper edge. If you stroke it with your hand, it feels like touching a blunt knife. The abdomen is small. For sexually mature individuals, milky white semen flows out of the genital opening when lightly pressed. The pectoral fins of this fish are smooth.

The maturity age of bighead carp in ponds varies greatly between the north and south, and their weight also varies greatly, mainly due to factors such as climate and nutrition. In addition, male fish mature one year earlier than female fish. The maturity age and weight of bighead carp in ponds in my country are: in South China, 2-3 years old, about 5kg; in Central China, 4-5 years old, about 7kg; in Northeast China, 6-7 years old, about 10kg.

2. Broodstock cultivation

(1) Broodstock rearing pond. It should be close to a water source, have good water quality, be convenient for irrigation and drainage, be open and sunny, and have convenient transportation. It should be 0.2-0.3hm2 in area, rectangular and easy to operate, about 2.5m deep, with a flat bottom, preferably loam with some silt. Routine cleaning and disinfection must be carried out before stocking broodstock.

(2) Stocking density. 10-20 fish (each weighing 10-15 kg) can be stocked per 1/15 hm2. In addition, 2-4 grass carp broodstock can be stocked. The total stocking volume per 1/15 hm2 (including the companion fish) should be 150-200 kg. The male-female ratio should be 1:1.5.

(3) Parent fish cultivation. Before stocking the parent fish, basal fertilizer should be applied first. After stocking, topdressing should be applied according to the season and specific measures of the pond. Generally, 750-1000 kg per 1/15 hm2 can be applied. In winter or before spawning, some powdered concentrated feed can be appropriately supplemented (about 20 kg of concentrated feed per fish per year).

3. Induced spawning of broodstock

(1) Selection of broodstock: The abdomen of the female fish is relatively swollen, and the area around the genital opening is plump, soft, and slightly elastic. The genital opening is ruddy, and the sacral bones can be vaguely seen when the abdomen is turned upside down. The tail is too high, and the outline of the ovary can be vaguely seen moving forward. However, if the abdomen of the female fish is too swollen and the elasticity disappears, it needs to be placed in a clear water pool or a micro-flow pool for a few days before inducing spawning. Male fish that can squeeze out milky white semen that disperses as soon as it enters the water can be selected.

(2) Male-female pairing: In natural spawning and fertilization, the male-to-female ratio is 1:1-1:1.5. In artificial insemination, the number of male fish can be less than that of female fish, and the semen of one male fish can be used to fertilize 2-3 female fish of the same size.

4. Estrus and artificial insemination

Water temperature above 18℃ can stimulate estrus, and the best water temperature is 22-26℃. Oxytocics are injected 1-2 times. One injection is a full dose injected into the fish body at one time. Two injections are the first injection (preferably pituitary or pituitary and hormone mixture) of 1/10-1/6 of the full dose. After more than 5 hours, the second injection is the remaining amount. Each injection is preferably 2ml of liquid. Under the influence of exogenous hormones, the broodstock produce a victory reaction, and the male and female fish are excited and chase each other in estrus. When the estrus reaches a climax, the male and female fish even twist together, vibrate their pectoral fins, ovulate, and ejaculate. Methods for collecting fertilized eggs: Start flushing stimulation 1-2 hours before estrus, and the fertilized eggs will gradually enter the egg collection box under the impulse of the running water. Then they can be picked up, counted, and placed in the incubator for incubation.

5. Incubation

Artificial hatching is to put the fertilized eggs into the hatching tools and hatch the fry under artificial management conditions. All water from rivers, lakes and ponds can be used for hatching. Sometimes tap water that has been exposed to chlorine or treated with sodium thiosulfate is also used and is considered safe. The hatching water temperature must be relatively stable and filtered step by step through three levels (40 mesh, 60 mesh, 80 mesh) through a filter pool or filter gate. Hatching tools include incubators, hatching buckets, hatching tanks, hatching loops, hatching troughs and plastic incubators, which should be selected according to local conditions. The hatching time varies depending on the water temperature. After 3 to 5 days of hatching, the fry's swim bladder has been inflated, the yolk sac has basically disappeared, and the fry can emerge when they can open their mouths and actively eat. Temporary training in bundles makes the fry strong and reduces excretion. When changing water on the way or when entering the pond at the destination, the water temperature difference cannot exceed 4°C.

3. Seedling cultivation and transportation

1. Cultivation

(1) Pond conditions

The area of ​​the bighead carp fry breeding pond is 1/15-1/15hm2, and the depth is about 1.5 meters. The pond embankment is firm and leak-proof. The pond bottom is flat with moderate silt and no aquatic plants. The fish pond faces the sun and has sufficient sunlight. It must be cleaned before stocking.

(2) Fish fry stocking density: 280,000 to 120,000 fry per 1/5hm2.

(3) Fish stocking:

When the body length is 30-60mm, single culture is mostly adopted, and the density is determined by the size of the pond, water depth, and fatness. It is generally appropriate to culture 2-3 species of fish, and at most 4 or 5 species, one of which is the main fish. When cultivating bighead carp, be careful not to mix it with silver carp, which has similar feeding habits.

(4) Feeding techniques and feeding amount

During the fish breeding period, artificial feed is used as a supplement. Before winter, about 1 kg of peanut bran or rice bran is added per 10,000 fish per day. After the weather turns cold, fertilization can be reduced, but the amount of peanut bran, rice bran, etc. added needs to be slightly increased to allow the fish to accumulate fat for the winter.

2. Transportation

(1) Requirements: fresh water, high oxygen content, healthy fish, appropriate density and easy operation.

(2) Methods: Carrying goods on shoulders, in vehicles, on boats, and on airplanes. The containers used for carrying goods include bamboo baskets, wooden barrels, canvas, and nylon bags.

4. Fish breeding

Pond Selection

The soil is loam, clay or sandy loam with good water retention. The pond size is 0.3-0.666ha, the pond shape is rectangular, the length-width ratio is 5:3, and the east-west direction is east-west. There are rivers and well water sources, and the water quality is pollution-free. The pond is equipped with water inlet and outlet facilities. The water depth of the pond is 2.5m.

Yield

1. Stocking fish species specifications, stocking quantity, adult fish specifications and output

Fish species size (g) Stocking quantity (tails) Combination species Adult fish size (g) Production (kg)

Silver and bighead carp

Solution 1 500 1000 100 50 500 500

Option 2 100 1000 100 50 750 750

Option 3 150 1000 100 50 1000 1000

2. The survival rate is over 95%.

Technical requirements

1. Water quality cultivation

(1) Transparency 20--25cm

(2) Apply base fertilizer: 200-500 kg of fermented human feces or chicken manure, or 500-1000 kg of manure per mu.

(3) Apply topdressing according to the water. When the transparency is greater than 25cm, apply 10-50kg of organic fertilizer per mu, or 2.5kg of inorganic fertilizer urea (nitrogen fertilizer), and 1kg of phosphate fertilizer. Organic fertilizer and inorganic fertilizer can be used alternately.

(4) Adjust the water quality once every 10 days, with a water injection and drainage volume of 20-30cm.

2. The fish species to be selected should be healthy, free of damage, disease and of uniform size.

(1) Stocking time: spring or autumn.

(2) Disinfection: Before the fish enter the pond, bathe them in a 10×10-6 malachite green or (1020)×10-6 potassium permanganate aqueous solution for 10-20 minutes.

(3) The water temperature difference before and after the fish enter the pond cannot exceed ±3

3. Pond disinfection: Before applying basal fertilizer, use quicklime with water for disinfection at 150mg/mu, and 75mg/mu for dry pond disinfection.

4. Equip one 1.5-kilowatt aerator for every 5 mu of water surface. Use the aerator reasonably and set the dissolved oxygen level at 4 mg/L.

4. Feeding and Management

1. Establish pond farming files.

2. Adhere to the pond inspection system, check whether the pond is damaged, whether the water quality has changed, and whether the fish are floating on the surface. If problems are found, remedy them in time. Check for dead fish. If dead fish are found, fish them out immediately, check the cause of death, and take preventive measures.

3. Regularly adjust water quality to ensure healthy growth of fish.

4. Make rational use of the aerator. Turn it on at noon on sunny days, in the early morning on cloudy days, and keep it closed in the evening. Turn it on before the fish head floats, and in the middle of the night when it is cloudy and rainy. Turn it on every day during the main growing season of fish.