Artificial breeding and stocking of bighead carp seed rearing technology

Artificial breeding and stocking of bighead carp seed rearing technology

_Zhao Wei

Bighead carp is the main species of artificial breeding and stocking, which has certain ecological effects and scientific research value. Huaihe Jingtuxia Carp, Longnose ■ Germplasm Resources Conservation Area was established in 2013 by the former Ministry of Agriculture with Announcement No. 2018, located in Huaiyuan County, Anhui Province, Huaiyuan River Jingtuxia Mountain Pass, the lower reaches of the Vortex River and the lower reaches of the Cihuai New River, which plays a very important role in the protection of Huaihe Water germplasm resources and aquatic biodiversity, Huaiyuan County breeding and stocking plan annual procurement of pond conventional cultivation of silver carp, bighead carp, bluefish, warped carp and other fry 2.3 million, of which bighead carp stocking accounted for about 35%. Due to the poor ability to resist the natural environment such as wind and waves, the weak activity and susceptibility to predation of the ponds, the survival rate after release is low, which directly affects the effect of artificial breeding and stocking. By optimizing the breeding technology of bighead ponds, the adaptability of bighead carp seedlings to natural water bodies can be effectively improved, and the survival rate of bighead carp breeding and stocking can be effectively improved, and the effectiveness of breeding and stocking can be improved.

First, pond preparation

Ponds used for the cultivation of bighead carp stocking seedlings are preferably 5 to 10 mu, which is convenient for cultivation and management. Before breeding, the bottom mud is cleaned, the thickness of the bottom mud is maintained at 10 to 15 cm, and the sun is fully exposed, so that the bottom silt is fully redoxed, which plays a role in killing pathogens, releasing fertilizer effect, and activating beneficial algae. Do a good job of pond slope and depth design to facilitate seed fishing, while paying attention to daily maintenance management and environmental hygiene cleaning.

2. Clear the pond for disinfection

7 to 10 days before the fry descend from the pond, use quicklime, bleaching powder and other drugs to clear the pond for disinfection. Quicklime clear pond: the bottom of the pool retains water depth of 20 cm, the use of block quicklime per acre 100 kg, the use of small wooden boats to add water to dissolve multiple times, holding a long-handled manure spoon, while hot the whole pool spilled, including the surrounding pond and the bottom of the pool, pay attention to observation after the completion of the operation, find that there are living aquatic organisms in the water to timely sprinkle quicklime, to achieve the purpose of thorough pond disinfection. The disinfection method of bleaching powder clear pond is the same as that of quicklime, and the dosage is 15 kg per mu of water surface at a water depth of 20 cm.

Third, water quality cultivation

After 4 to 5 days of quicklime clear pond or 2 to 3 days after bleaching powder clear pond, add filtered fresh river water to a water depth of 60 to 80 cm, and at the same time apply about 200 kg of fully fermented cow manure and 1 000 ml of EM bacteria per mu of water surface, and after 3 days, the water color is tea brown or oil green, yellow green, and the transparency is 30 cm. Illuminate the water surface with lights at night, naked eye observation can see a large number of gray and white dots in the water body, that is, rotifers, no or very little can see the branches, copepods, indicating that the water quality is well cultivated at this time, is the best time to release bighead carp seedlings.

Fourth, quality identification and precautions for the lower pond

In late April every year, the middle and lower reaches of the Yangtze River have successively carried out the breeding of four major fish fry, and artificial breeding is the only way to obtain a large number of bighead carp seeds. Bighead carp fertilized eggs generally take the ring channel micro-flow water method to hatch, the most suitable water temperature of about 25 ° C, about 60 hours after the membrane break, the seedlings can swim in parallel and take the initiative to feed, need to catch the pond in time. The time of seedlings under the pond is too early, the seedling organs and tissues are not perfect, it is easy to sink to the bottom of the pool in still water, there is not enough oxygen supply, and it is easy to cause the phenomenon of dead seedlings or even the total annihilation of the army; The seedlings are too late in the pond, and the bait such as water rotifers is not taken in time, and insufficient nutrition will cause stagnation of development, the weak physique of the seedlings, and the lack of ability to reverse the water, which will seriously affect the survival rate of cultivation. When purchasing seedlings, pay attention to incubation and development time, put an end to the release of early seedlings and late seedlings, and ensure the survival rate of bighead carp cultivation. Fry should be stocked from 17:00-18:00 on sunny days. Fish fry transportation generally adopts double-layer nylon bag oxygenation packaging, each bag is filled with 5 kg of water, 100,000 seedlings are loaded, oxygenated and sealed, and transported by car to The mouth of the pond. If the transportation distance is short, the operation with a bucket can be taken directly, and the transportation time is required to be within 5 minutes. Stocking density of 300,000 tails / mu, generally single breeding, polyculture is not recommended. When releasing seedlings, choose to be in the windy place on the pond, open the mouth of the bag, and gently put the fish with water into the water, and avoid savage operations to muddy the water body. When short-distance barreled fry are released, they should also be gently placed in the water with fish belt water to prevent rough movements.

Methods to identify the advantages and disadvantages of bighead carp seedlings: (1) Take a small amount of water in a shallow basin, put in about 100 seedlings, move the water body with your fingers along one direction to make the water flow, stand in the shallow basin, observe the activity of the seedlings, the one who is active against the water is a high-quality seedling, and the drifter is an inferior seedling. (2) Observe the appearance of seedlings. The body color of high-quality seedlings is grayish yellow and the body is thick, and the inferior seedlings are black and thin. (3) Check the activity of bighead carp seedlings in the incubation equipment. Healthy seedlings move actively and actively in the middle of the water body, while frail seedlings tend to stick to the pool wall and filter and move slowly.

Fifth, feed processing and feeding management methods

Bighead carp seedlings can be artificially fed on the second day after they descend the pond, and the soybean milk feeding method saves time and effort, and the effect is remarkable.

Soybean milk production method: choose fresh soybeans, soak in water 5 to 6 hours in advance, so that the soybeans are completely soaked and there is no hard heart between the two pieces of watercress. Use the three-phase electric soybean milk machine to grind and feed, pay attention to adjusting the fineness of soy milk when grinding, add water appropriately, and the fineness of soybean milk particles can pass through the 40 mesh filter.

Feeding method: sprinkle throughout the pool, feeding 3 times a day, the specific time is 9:30, 14:00, 17:30. The feeding amount is calculated according to the breeding area, and 1 kg of soybean milk made of soybeans is fed per mu of water surface per day, and after 7 days, it is fed powdered feed and puffed feed.

The ratio of flour raw materials is calculated according to the 3:5:2 of soybean cake, bran and vegetable cake, and the processing fineness is 18 to 20 mesh. Feeding at the upper wind outlet, feeding once in the morning and afternoon, the daily feeding amount is 8% to 10% of the weight of the fry, depending on the feeding situation, generally after feeding for half an hour, there is no bait left on the water surface. The extruded compound is 0.5 mm in diameter and has a crude protein level of 36%.

Sixth, the prevention and control of diseases at the seedling stage

1. Wheelworm disease

It is a common protozoal disease, manifested by emaciation of fry, blackening of the body, inaction to feed, taking gill tissue or tail fin of the diseased fish for water immersion, microscopic observation can see a large number of wandering wheelworms.

Prevention method: prevention with 10 mg / elevated potassium manganate solution soaked, treatment can be treated with copper and iron mixture 0.7 mg / l, or neem branches and leaves 50 g / m3, decoction of water to extract the juice, the whole pool sprinkled.

2. White-headed white-mouthed disease

Bacterial disease, the causative agent of a myxococcus, can also be secondary to rotifer infection. It is characterized by white-headed white-billed or red-headed red-billed symptoms, which are generally prone to this disease about 20 days after the bighead carp seed goes down to the pond, which is caused by a large fry density, parasitic infection, and unclean water quality.

Prevention and control methods: appropriately reduce the density of breeding, regularly use water disinfectants, use bleach powder externally during treatment, so that the concentration of drugs in the water body reaches 1 to 1.2 mg / l, internal administration of kanamycin, according to the weight of the fry mixed with bait feeding, the dosage is 10 ~ 30 ml / kg, continuous use for 3 to 5 days.

3. Bubble disease

This disease is caused by the fry accidentally eating bubbles in the water body or the gas in the water body is oversaturated and then entering the fish body to form an embolism, which can cause the fry to be unable to move normally, or even die.

Prevention and control methods: reduce the density of aquaculture, increase the amount of feeding, regularly add fresh river water, maintain a high water level, improve the fertility of the water body, and maintain the appropriate transparency of the water body.

7. Adaptive domestication of stocking

Before artificial release, in order to adapt the bighead carp seedlings to the river environment, the following domestication operations need to be done.

1. Drag the net for exercise

After about 30 days of breeding, the body length of bighead carp can reach 3.5 to 4.0 cm, the body color is gray and yellow, and the head is generally strong. At this time, it is appropriate to pull the net to exercise the physique of the fry. Choose sunny weather when pulling the net, and the movement requires slow and light. Immediately after the first netting, the net mouth should be opened, so that the fry can escape the operating area as soon as possible, and then the pond is flushed to prevent the fry from lacking oxygen. The next day, the second net is pulled, and after the second net is netted, the container is trapped, and the length of time of the trapped fish is determined according to the activity of the fry, and the hypoxic floating head is found to be immediately released from the cage. After several net pulls, the fry's physique has been fully exercised and their physical fitness has been significantly improved.

2. Running water irritation

One week before artificial release, combined with the dragnet exercise, increase the number and time of water injection, simulate the natural habitat of rivers and lakes, so that the fry are in the flowing water body, exercise the physique of the fry, and adapt to the future environment as soon as possible.

3. Feeding management

It is required that the water quality in the early stage of cultivation has appropriate fertility, and the natural food of the water body is rich, which can meet the needs of growth and development, improve disease resistance, and promote the healthy growth of bighead carp seedlings. In the later stage, under the condition of ensuring sufficient bait, photosynthetic bacteria or EM bacteria are applied twice a week, and the water surface per mu is 500 to 1 000 ml. Do not use disinfectants for 3 days before and after the use of microecological preparations, so as not to affect the use of microecological preparations. In the early stage, only soybean milk and powder are used, and in the later stage, special commodity feed is used for puffing, and the protein of the puffed material is required to be about 36%. Strengthen water quality management, create a good living environment for bighead carp seed, ensure the quality of fish fry, and improve the effect of artificial stocking.