Broodstock Selection and Cultivation
The light-colored yellow pelagic broodstock was selected as a broodstock of age III and weighing 2.5 kg or more. It was robust and harmless. Well-being healthy individuals did broodstock, and the ratio of male to female was 2:1. They were placed in cages in the sea area for intensive cultivation from March to April every year. , The cage size is 3m 3m 3m, stocking density is 15 - 20 / box, select high quality fresh or frozen blue circle, sardines, squid and other high quality feed fish fed, and in the feed amount of vitamin B And vitamin E (vitamin B: 500 mg per week, tail, vitamin E: 200 mg per week/tail). The LRH-A artificial hormone was injected every two weeks to promote ripening. In the breeding season (from the end of April to early June), choose large and soft abdomen, females with prominent anal and ruddy, take eggs and observe that most of the eggs of females develop to IV stage. Males have light pressure on abdomen with white semen outflow. The broodstock elicited production.
Artificial oxytocin
In the water temperature stabilized at 25 °C above, the specific gravity of 1.018-1.024 under the environmental conditions, that is, intramuscular injection of oxytocin. Female fish injected HCG 400-500 IU / kg fish and LRH-A 6-8 ug / kg fish, male fish injected HCG300-350 international units / kg of fish body, the general effect of hormone injection time is 36 hours -40 hours, The broodstock can naturally spawn and fertilize.
Incubation of fertilized eggs
Fertilized eggs are collected by running water method (spawning in cement ponds) or collected by 100-mesh sieve nets (spawning in cages). After washing to remove impurities and dead eggs, use 15-20 g/m3. The PVP iodine was soaked in the outdoor cement pool after 5-8 minutes of incubation. The water for incubation is precipitated, filtered and sterilized. The specific gravity of seawater is 1.018-1.024, the pH value is 8.0-8.3, the water temperature is 24°C-28°C, and the membrane normally hatches after 18 hours-22 hours.
Larval rearing
After hatching, the larvae are hatched and transferred to a cement pool for cultivation. Chlorella is introduced into the cement pool in advance (so that the water is light green). The larval rearing temperature is 24°C-28°C, the specific gravity is 1.016-1.022, and the pH value is 8.0-8.3. 5 mg/l, ammonia nitrogen
Earthen crude
1. Clear pond cultivation Choose 2-5 acres, 1.2-1.8 meters deep pool, flat pool bottom, sand and mud rectangular soil pool for cultivation. Use tea bran (20-30 g/m3) and bleaching powder (60-80 g/m3) to clean the pond, remove 0.6-0.7 meters of water for the first time, apply 15 kg of organic fertilizer (such as chicken manure). Mu, simultaneous application of photosynthetic bacteria (applied according to the product instructions), after 5-7 days of cultivation, the food organisms in the pool have been extensively propagated (rotifers, copepods, and total nohidarchy greater than 2000/liter).
2. Feeding and managing larvae Stocking densities of 150,000 to 200,000 tails/acre. After the ponds have started, they can start splashing the squid feed to maintain a good water color and the abundance of food organisms. When the larvae are up to 0.7 cm in length, they can be fed with cladocera, Artemia nauplii, and copepods. When larvae are up to 1.2 cm long, they can be fed with fresh meat, the frequency of feeding is 4-6 times a day, and the amount of feeding is 20%-30% of body weight. During the feeding of meat, the complex vitamin B is added to the meat. , Cod liver oil and oxytetracycline, increasing the daily water exchange capacity, and weekly photosynthetic photosynthetic bacteria to ease the eutrophication of the water caused by the seed of feces and residual bait to maintain the water quality of fresh. When the fish body up to 1.8 centimeters or more can feed artificial compound feed with a diameter of 0.3 millimeters. After about 40 days of cultivation, the fry grows to about 3 centimeters, and the survival rate reaches 14%.
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