Breeding techniques of herring

Herring is an excellent species of freshwater aquaculture in China, using benthos as bait, with fast growth, large size, tender meat, delicious taste, high fat and protein, and high vitamin content, so it is deeply valued by the masses and professional farmers. The demand for fish fry is increasing day by day, and there are broad prospects for artificial reproduction of herring.

Breeding methods of fish fingerling

Herring fingerling should choose more than 6-year-old herring species weighing more than 15 kg, physically strong, no damage, male and female according to 1:1 ratio of herring species for storage. The area of the storage pond is 3-7 mu, the water depth is more than 2 meters, the bottom of the pond is flat, the soil is loam, 1-2 per mu, and the herring is concentrated in a special pond one month before spawning.

Herring species are mainly fed with fresh snails and clam meat, supplemented with a small amount of vegetable cake and bean cake bait, flushing regularly, usually once a month in winter, 5-7 days a month after the beginning of spring, and every 3-5 days before delivery, in order to promote the gonadal development of green fish.

Design of parent fish culture pond

1. Location: the parent fish culture pond should choose the pond with leeward to the sun, sufficient water source, good quality, strong soil water retention, convenient drainage, irrigation and transportation as the parent fish culture pond.

2. Area: the fish pond had better be rectangular, with an area of 2000 to 4000 square meters.

3. Water depth: the water depth is generally 1.5 to 2.5 meters, the water level should be deepened in winter to keep warm, and the water level should be lowered in spring and summer to increase the water temperature.

4. Water quality: the water quality should be fertile and the bottom of the pool should be flat.

5. Greenhouse: the temperature suitable for herring growth and development and spawning is 20: 30 ℃. Building warm-shed parent fish pond can lift the restriction of low temperature on fish gonadal development and improve the quantity and quality of parent fish spawning. When using greenhouse, opening greenhouse windows at noon every day or using aerator to increase oxygen artificially can increase water temperature by 5-7 ℃ and make dissolved oxygen reach 4-5 mg / L.

Breeding techniques of herring

1. The time of induced labor: the time of induced labor is generally in the middle and last ten days of May, the water temperature is 22-30 ℃, and the most suitable temperature is 25 ℃.

2. Selection of maturity of herring: the maturity of herring directly affects the effect of induced spawning. herring should be strictly selected when it is used to induce childbirth. The selection standard of male fish is that semen flows out of the reproductive pores of abdomen, which can be dispersed after warm water, and the abdomen of female fish is inflated, soft and elastic, and the abdominal scales are sparse.

3. Use of oxytocin: common drugs for induction of labor of herring are "PG", pituitary gland, "LRH-A' luteinizing hormone releasing hormone analogue" and "HCG'". Induction agents such as chorionic gonadotropin, GTH gonadotropin, "DOM" dione, etc., usually use a mixture of 3-4 drugs to induce labor, and the second injection method is higher. The female is injected with LRH-A2-5 mg / kg in the first injection, and the needle distance is 8-12 hours. The second injection dose is LRH-A10-20 mg + PO2-4 mg + HCE500-11200 international unit or plus DOM5 mg, mixed into a mixture. The male fish was injected intraperitoneally. The injection dose of male fish was 1 beat 3-1 beat 2 of the dose of female fish, and the effect time was 8-10 hours.

4. Estrus: after injecting the second injection of spawning agent, put the herring species back into the spawning pool, and so on, when the effect time is reached, artificial egg collection and fertilization is carried out in time when the herring is in estrus. The benefit time varies with the water temperature, the water temperature is 25-28 ℃, and the benefit time is 8-10 hours. At this time, the herring estrus should be carefully observed. As soon as the time for oestrus arrives, catch the herring and clip it with fish sticks for inspection. At this time, if the female fish gently press the abdomen, the eggs can flow out of the reproductive pores, and the males can squeeze out the semen and warm water to spread quickly, they can start artificial egg harvesting.

5. Fertilisation: artificial fertilization in dry water. If the natural sperm eggs cannot be collected, put the herring back into the spawning pool and wait for the herring to be in estrus. The collected eggs and sperm should be fully mixed to fertilize and avoid direct sunlight to kill the eggs during artificial insemination. After insemination, the fertilized eggs should be diluted with water and put into the loop to hatch. Personnel, tools, washbasins, nets, fish beds, brushes and other preparations should be done before artificial insemination, and the personnel should coordinate and cooperate to achieve brisk action so as to avoid injury to the green fish.

6. Loop hatching: artificially collected fertilized eggs should be timely put into the loop water prepared in advance to hatch, with a honey of no more than 1.2 million eggs per square meter. The flow rate in the loop should be appropriate. In the early stage, the flow rate of water is about 17 cm / s, and the expanded fertilization can be washed and rolled to the surface. When the fish fry just come out of the film, the management should be strengthened to prevent the fish eggs from sticking to the ring filter cloth to prevent the flow of water, so it is necessary to increase the flow rate of the water (30 cm / s), and at the same time to prevent the fish from sinking or suffocating with the filter cloth. After the fry sees the waist point, the water flow rate should be reduced to avoid consuming the fry's physical strength. Eight hours after the waist point, the fish fry can be sold in the box. after the fry can be eaten, they should be fed four times a day, one egg yolk for every 100000 fry, so as to enhance the physique of the fry.