Intensive cultivation techniques of grass carp one-year-old fish species

The survival rate of grass carp one-year-old fingerlings is usually low (usually only about 30%), and their specifications are small and the number is seriously insufficient, which has become a major obstacle to the current production of fingerlings. In recent years, we have adopted intensive cultivation techniques to improve the pond environment, early stocking, and scientific feeding. As a result, the survival rate of grass carp one-year-old fingerlings has reached more than 80%, and the specifications for the out-of-pool range from 100 to 150 grams. More than 500 kilograms (including 300 kilograms of one-year-old fish species). The specific measures are as follows:

First, improve the pond environment

In the past, the species pools were generally small and shallow, and floating species often occurred. In particular, the floating heads were floating every day during the rearing period, which not only inhibited the growth of the species, but also affected the water quality. Therefore, we must improve the pond environment so that its water depth reaches 2 to 3 meters, and the area increases to 3,000 to 5,000 square meters. At the same time, it is equipped with an aerator (0.5 kW per mu). Under this condition, as long as the irrigation and drainage water is convenient, feeding and fertilizing can keep up, and the summer fish and grass carp can grow to 10 cm in 1 month, which is about 3 cm longer than the ordinary shallow water pond. In the later stage of growth, weight gain can be increased. Therefore, the survival rate and yield of fingerlings in deep pools are significantly improved.

Second, timely early release

In order to alleviate the conflict between water quality, food, and space between the grass carp and the fish, grass carp should be obtained as soon as possible. At present, the use of greenhouse artificial propagation of early propagation seedlings is more effective. However, the stocking is too early and the fish fry easily freezes when it is cold. Therefore, the water temperature should be kept above 15°C and the seedlings can be planted. When the rearing fish meets the specifications of the out-of-pool, the fish should be deferred to the pool in order to further expand the size of the main fish and strengthen its ability to bait. In particular, carp seedlings and grass carp seedlings are the most contradictory in the competition of diets for concentrate feeds, so they should generally be 40 to 45 days lower than early bloom. The stocking density of the total production of 500 kg of fish per acre cultivation pond is 3,000 to 3,500 fishes, 800 to 1000 fishes, 1000 to 1500 fishes and 1,500 to 2,000 fishes.

Third, nurture natural food

After Qingchi, 400 kg to 500 kg of organic fertilizer is applied per acre. Use bamboo to divide the surface of the water into crisscross shapes, then add 15kg to 25kg of duckweed per acre. After 5 months, organic fertilizer is applied every 35 days to 40 kg, or diluted with 1 kg of ammonium bicarbonate and 500 g of superphosphate, and the whole pool is splashed to accelerate the breeding of duckweed and cultivate natural food.

Fourth, pay attention to feeding flush

The grass carp does not need to control the amount of food after going down the pond. It should be done after the food is eaten. It requires that the grass carp should be more than 10 cm above the rearing pool and the specifications should be uniform. When the summer flower is under the pond, it mainly feeds on the genus Cladocera and duckweed, and 2 days to 3 days before the duckweed is eaten, it allows the fish species to switch to the shredded tender grass or the black algae. Special attention should be paid to high temperatures, stifling heat, and thunderstorms. Fish species can easily float, and appetite loss should be properly controlled. When the high temperature season is over and the water temperature falls below the optimal water temperature range below 30°C, it is time to feed enough feed to ensure rapid growth in the later period. In general, the annual feed amount per acre is between 800 kg and 1000 kg, and the feed for green feed is between 1500 kg and 2000 kg.

Grass carp enjoys fresh water quality. The first-year-old grass carp is mainly herbivorous, so it has more manure and water quality. Therefore, it must be flushed frequently. Within 20 days after Xiahuaxia, new water should be refilled once every 2 days, each time 10 cm deep. After 20 days, in addition to regular replenishment of new water, part of the old water should be discharged. The transparency of water quality can be maintained at about 35 cm. In order to promote the appetite of grass carp, the number of flushes will gradually decrease after late September.
Fifth, to strengthen the prevention and treatment of fish diseases

Before the fish swimming in the pool, it was soaked with 3% to 4% saline for 15 minutes to 20 minutes to kill pathogens on the surface of the fish or the pelvis. When the grass carp grows to about 10 cm, an inactivated vaccine for grass carp hemorrhage is used to prevent grass carp bleeding. At the end of July and early August, 20ppm-30ppm lime solution was used to splash the whole cell to control bacterial gill disease. In mid-August and mid-September, 0.2ppm of ferrous sulfate was splashed once to prevent enteritis. At the same time, furazolidone was used for 2 courses (each course of treatment for 3 days to 4 days, 1 kilogram of food containing 1 g to 1.5 g of baits, made into pellets).

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