CATDOLL : CATDOLL: How to breed silver carp? How to breed silver carp?

How to breed silver carp? How to breed silver carp?

1. Breeding pond: Silver carp needs to be built in a sunny place with sufficient water source, and the appropriate area is between 4-8 acres.

2. Water depth: Normally it can be between 1.5-2 meters, and more than 2 meters in winter.

3. Food: The main food of silver carp is plankton in the water, so it is necessary to add appropriate amount of organic fertilizer to the water to cultivate plankton.

4. Water quality: When the water quality deteriorates, it is necessary to change and clean the water in time.

5. Disease prevention and control: Pay attention to monitor the condition of the fish and take timely prevention and control measures when symptoms are found.

What are the farming techniques for silver carp?

Organic fertilizer should be applied before stocking for cultivation. For silver carp, base fertilizer should be applied in appropriate amounts to control the peak period of wheel worms being released into the pond.

1. Silver carp is a pelagic fish. In spring, summer and autumn, it spends most of its time swimming in the middle and upper layers of the water to find food. In winter, it dives into deep water to hibernate. It is a typical filter-feeding fish that relies on the special structure of its gills to filter plankton in the water and feeds on plankton all its life.

2. They mainly feed on zooplankton in the fry stage, and gradually turn to phytoplankton when they are more than 1.5 cm long. They also like to eat grass carp feces and chicken and cow dung. They also eat soy milk, bean dregs powder, bran and rice bran, etc. They like to eat artificial micro-granular feed. They are very interested in sour food and have a strong appetite for rotten food. They are often raised with grass carp. Silver carp eats grass carp feces, so there is a saying that one grass can feed three silver carps.

3. Silver carp's food has obvious seasonality. In spring and autumn, in addition to plankton, it also eats a lot of detritus bait. The lower the water level in summer, the more it feeds. It eats less and moves less during the winter. It is suitable to be raised in fertile water. The length of the intestine is about 6-10 times the body length. The appetite is proportional to the water temperature. Silver carp likes high temperature. The most suitable water temperature is 23℃~32℃. In the hot summer, silver carp has the strongest appetite.

4. Silver carp is lively and likes to jump. It has the habit of swimming upstream, but it is not very agile and is rather clumsy. It likes fertile water. Similar individuals often gather in groups and swim in the middle and upper layers of the water, especially in clear water areas with fertile water. However, it is timid and afraid of being disturbed. When disturbed or touching the net wire, it will jump out of the water and escape over the net.

5. Silver carp grows fast and has a high yield. It reaches sexual maturity 1-2 years earlier than grass carp, and mature individuals are also smaller. Generally, female fish weighing more than 3 kg can reach maturity. Female fish weighing about 5 kg have a relative egg capacity of about 40,000 to 50,000 eggs per kilogram of body weight. The spawning period is similar to that of grass carp. It spawns from April to May every year, with an absolute egg capacity of 200,000 to 250,000 eggs. The eggs float, and the spawning period is similar to that of grass carp.

6. Silver carp has a very poor tolerance to low oxygen. It will float to the surface immediately when there is a lack of oxygen in the water, and some will die quickly.

1. Food habits

Silver carp lives in the upper layer of water, mainly feeds on phytoplankton, and also eats a small amount of zooplankton. Rotifers are the first bait cultivated in the pond for fry, and they also like to eat soy milk and other artificial concentrated feeds of similar size to rotifers. As the fry continue to grow, after the summer flowering stage, the gill rakers are basically grown, and gradually turn to filter feeding on phytoplankton. Through pond fertilization and water quality cultivation, silver carp can grow well, and they like to eat all kinds of powdered artificial concentrated feeds at all growth stages.

2. Growth Silver carp is a large economic fish that grows fast. Sexual maturity is 3-4 years old (in the Yangtze River Basin). Weight gain is fastest between 3-6 years old, and then slows down; body length growth is faster between 1-4 years old, and slows down after the 4th year.

3. Reproduction

Silver carp is a fish species that lives in large rivers. Under natural conditions, there are spawning grounds in the main main rivers of my country. Parent fish can swim to the spawning grounds to spawn and reproduce during the spawning season, but this is not possible under artificial pond conditions.

The sexual maturity age and individual size of silver carp are closely related to latitude (heat). In southern my country, sexual maturity age is 2-43 years old and weight is about 2kg; in central China, sexual maturity age is 3-4 years old and weight is about 3kg; in northeast China, sexual maturity age is 5-6 years old and weight is about 5kg. In addition, sexual maturity is also related to nutritional conditions. Different nutrition will lead to different sexual maturity age and weight. Males are generally one year earlier than females and are smaller than females.

2. Artificial breeding

1. Broodstock selection

Selecting qualified broodstock with good germplasm and physique is one of the basic conditions for artificial breeding of grass carp. The so-called good germplasm means that according to the investigation and research on the germplasm of the "four major carps" in the "three rivers" (Yangtze River, Pearl River, and Heilongjiang River) of my country, the germplasm of the Yangtze River is the best, so it is more ideal to choose the original grass carp of the Yangtze River. The so-called good physique means that the fish is strong, with normal body color, complete scales, and no injuries or diseases. Individuals that have not reached sexual maturity are used as reserve broodstock, and mature individuals are used as broodstock for production that year. When selecting broodstock, attention should also be paid to the matching of males and females. Generally, there are slightly more males than females.

2. Broodstock cultivation

(1) Broodstock rearing pond. The area of ​​the broodstock rearing pond is 2/15-4/15hm2 (2-4 mu), and the water depth is 1.5-2.5m. It is located near the spawning pond, with convenient drainage and a quiet environment. Use quicklime to clean the pond before stocking.

(2) Stocking density. About 1500-2250 kg of broodstock are stocked per hectare of pond. The male-female ratio is 1:1 or 1:1.25. In order to make full use of bait and adjust water quality, on the premise of mainly raising grass carp broodstock, 50-60 bighead carp broodstock or reserve broodstock, about 30 grass carp and black carp broodstock or their reserve broodstock, and about 30 ferocious fish can be mixed per hectare.

(3) Feed. The natural food of silver carp broodstock is mainly phytoplankton. By fertilizing the pond and improving the water quality, it can make them grow well. Silver carp also like to eat all kinds of concentrated feed. In order to strengthen their physique, adding some bran and bran concentrated feed after spawning, in autumn and early spring is beneficial to the development of gonads.

3. Induced spawning of broodstock

(1) Time and water temperature for inducing labor: In the middle and lower reaches of the Yangtze River, the time for inducing labor is May to June, and the most suitable water temperature for inducing labor is 24~26℃.

(2) Selection of broodstock: The maturity of broodstock directly affects the effect of induced spawning. The identification criteria are that when the abdomen of male fish is gently squeezed, semen flows out and immediately disperses when it comes into contact with water, and the abdomen of female fish is swollen, soft and elastic, and the scales on the abdomen are sparse. In order to improve the maturity of the group, a net can be pulled for inspection in mid-April. For those with poor maturity, LRH-A 3~5 micrograms/tail can be injected according to individual size and maturity.

4. Estrus and artificial insemination

Water temperature above 18℃ can induce estrus, and the best water temperature is 22-26℃. Oxytocics are injected 1-2 times, with an interval of 6-12 hours between the two injections. The time from the last injection to ovulation is generally 9-12 hours. Parent fish chase each other in estrus in the spawning pool within the scheduled time. The male fish constantly hits the abdomen of the female fish with its head, rubbing each other. The female fish twists its abdomen with its back, trembles its pectoral fins from time to time, ovulates and ejaculates, and cooperates closely. It is best to collect eggs about 1 hour after spawning. Artificial insemination technology can also be used.

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 grass carp seedling cultivation pond is 1/15hm2, the pond depth is about 1 meter, the pond bottom is flat, and there is little silt (about 5 cm). The water source is sufficient, the drainage and irrigation are convenient, and the pond embankment is firm and leak-proof.

(2) Fish fry stocking density: 2.25 million to 3 million fry per hectare.

(3) Stocking of fish: Silver carp accounts for 60%-65%, with bighead carp 10% and grass carp 30%; or bighead carp 10%, common carp 20% and grass carp 10%; or bighead carp 15% and grass carp 20%; or black carp 35%-40%.

(4) Feeding techniques and feeding amount

Silver carp have the habit of feeding at night, so pay special attention to increasing the amount of feed between 11 and 12 o'clock at night. When the fish is 10-16 cm long, the amount of feed is 6%-10% of the total amount of fish, and when the body length is over 16 cm, the amount of feed is 3%-5%. Feeding should be done at a fixed time, location, quality and quantity.