8 key points of safe overwintering of parent shrimp with good breeding benefit and high reproductive benefit

Parent shrimp

1. Strict selection: parent shrimp overwintering for a long time, must be strictly selected. Selection criteria of parent shrimp: large body, no disease, no damage, no deformity. The body length of female shrimp is 14cm, while that of male shrimp is more than 12cm. Practice has proved that the survival rate or utilization rate of large individual parent shrimp cultured in low density is high. Soft shrimp that has just molted its skin cannot be used as a parent shrimp.

two。 Indoor disinfection: when parent prawns enter the pond, add 100 million 150 × 10 20cm~30cm formalin or 20 g / m3 potassium permanganate to soak for 1 hour, then fill up the pool water gradually.

3. Temperature control: facts have proved that the heating up of unburned coal in winter and the culture method of directly entering the pool with deep well water will cause the phenomenon of weight loss of parent shrimp, blurred edge of egg band, scattered spawning and low hatching rate in spring. Therefore, after the parent shrimp entered the pond, the temperature began to rise when the water temperature naturally dropped to 8 ℃. In winter, the water temperature is stable at 8 ℃ ~ 9 ℃, and the temperature difference between day and night is less than 1 ℃. When changing water, the temperature difference should not be too large, the sea water should be preheated first. It is best to have heating in the room, so that the room temperature is slightly higher than the water temperature, and the roof is insulated by facilities such as straw curtains.

4. Food treatment: the main food of parent shrimp during the overwintering period is fresh and pollution-free shellfish, squid, mixed fish and shrimp meat, sand silkworm and so on, among which the live silkworm has the best effect. If you use frozen products, you need to match a certain amount of live bait. Before feeding, the bait should be washed or soaked with potassium permanganate. When feeding sand silkworms, you need to soak in fresh water for dozens of minutes to kill parasites. Frozen aquatic products should not be single, should be mixed, play a complementary role in nutrition, conducive to the gonadal development of parent shrimp, improve the spawning rate and hatching rate.

5. Water quality control: water temperature control indicators during the overwintering period: salinity 23: 35, ammonia nitrogen 0.5 mg / L, dissolved oxygen 4 mg / L, chemical oxygen consumption less than 3 mg / L, heavy metals and other pollutants are in the fishery water quality standard. Water should be changed, contaminated and inflated regularly, with a daily water exchange of 20% to 30%.

6. Indoor lighting: generally below 500 lux, in addition to shading with ceiling grass curtains, black plastic film or black cloth should be used above the cultivation pool. When changing water, brushing the pool, feeding and other operations, do not make the light too strong, so as not to affect the parent shrimp overwintering.

7. Medicine for disease prevention: drug abuse will make parent shrimp survive the winter in a "medicine jar". When raising seedlings in spring, there will be more dead shrimp, less spawning or no spawning. The correct disease prevention measures are as follows: (1) soak the pool water with 10 g ~ 20 g / m3 bleach for 5 ~ 7 days. (2) parent shrimp disinfection: regularly sprinkle with oxytetracycline and other antimicrobials. (3) sprinkle methylene blue 0.05 g ~ 0.1 g / m3 and formaldehyde 25 × 10 × 10 Mel 6 once a week or every other week. (4) bait disinfection, use potassium permanganate 200g ~ 500g / cubic meter. (5) pick out dead and diseased shrimp at any time to prevent cross-infection.

8. Graded cultivation: on the basis of normal management, it was selected and graded according to the gonadal development of parent shrimp, and cultivated in different ponds according to the situation. By properly adjusting the water temperature of gonadal development and promoting its synchronous development, the number and time of spawning are concentrated accordingly, so as to facilitate the arrangement of production. Generally, the daily temperature difference of heating or cooling is less than 1 ℃.