High-yield and high-efficiency techniques of cultivating grass carp in ponds in two seasons a year

The main culture of grass carp in pond is one of the main culture modes of freshwater fishery in Shaxian County, most of which belong to traditional conventional culture, with small stocking size, long culture cycle, insufficient investment in culture equipment, high labor intensity, low yield, general yield per mu in 400kg~750kg, annual profit of about 1000 yuan per mu, and low economic benefits. In order to improve the yield and economic benefit of pond culture, the author demonstrated the high yield and high efficiency culture technology of grass carp in pond in 2006. Measures such as putting in large size fish species, reducing the amount of low quality fish, expanding the number of famous and high quality species, being equipped with automatic bait feeding machine and aerator, injecting frozen stem cell attenuated vaccine and "triple" vaccine into grass carp to improve the survival rate, popularizing and feeding full price pellet feed, twice a year, twice in dry ponds and other measures, from traditional coarse culture to intensive culture and intensive farming, and popularize the cultivation of forage grass The use of wasteland, winter fallow fields, pond ridge planting ryegrass, elephant grass, Sudan grass and other high-quality grass to feed grass carp to supplement the lack of off-season green feed. In the past year, the pond area was 156mu and the average yield per mu reached 1602.7kg in Shaxian freshwater aquaculture farm.

I. Pond conditions

The aquaculture demonstration pond area is 156mu, a total of 18, each pond area is 5mu ~ 13mu, the water depth is 1.9m~2.5m, the water source is sufficient, the water quality is fresh and pollution-free, the pond drainage and irrigation is convenient, equipped with sufficient electric power, and the transportation is convenient.

Aquaculture machinery

The water surface with an area of 3 mu ~ 5 mu is equipped with an aerator with a power of 3kW, and each pond is equipped with an automatic bait feeding machine. The aerator and bait feeding machine are used to control the oxygenation time and feeding time automatically by microcomputer.

III. Matching of fish ponds

The adult fish ponds with an area of 5 mu are equipped with 1 mu fish ponds to cultivate large size fish species and ensure that there are sufficient sources of large size fish species.

IV. Disinfection of ponds

From 7 to 10 days before the fish went into the pond, the pond was 1 m deep, and the whole pond was disinfected with 7kg/ mu ~ 10kg/ mu of bleach containing 30% chlorine.

5. Fish fingerling restocking

The stocking time of the first season is January. The average stocking size of grass carp fingerling is from 250g/ to 350g/ per mu, silver carp with 150g/, bighead carp with 150g/ and Jian carp with 250g/ per mu are 60, 30 and 54 / mu respectively. The stocking time of the second season is June, with an average of 540 grass carp fingerling from 150g/ to 200g/, 86 silver carp with 100g/, 36 bighead carp with 100g/, 143Jian carp with 15g/-20g/ and 20 big-mouth catfish with 15g/.

VI. Vaccination

In order to improve the survival rate of grass carp culture, all grass carp fingerlings were injected with frozen stem cell attenuated vaccine and triple "three diseases" vaccine. The vaccine injection method is as follows: when releasing grass carp fingerling, a large wooden bucket (or plastic basin) of grass carp is prepared next to the pond, and the solution is prepared according to the dosage ratio of 50kg water containing 90% crystal trichlorfon and salt 0.8kg. Grass carp are disinfected and anesthetized in batches, and frozen stem cell attenuated vaccine powder (1 ∶ 1) is diluted with "triple" vaccine liquid. Each grass carp is injected with 0.3mL. The injection site was the base of dorsal fin, the injection angle was 45 °, and the injection depth was about 0.5cm.

VII. Feeding and management

1. The feed feeding method was combined with pellet feed and green feed. One feed table is set up for each pond. In the early stage of culture, artificial ryegrass was mainly fed with pellet feed when the water temperature was 15 ℃ ~ 22 ℃, and full pellet feed was fed mainly with green feed when the water temperature was normal and stable at 23 ℃ ~ 30 ℃. According to the order of feeding green feed and then pellet feed, the feeding should be timed, positioned, qualitatively and quantitatively. When feeding pellet feed, we should do a good job of feeding and domestication, so that fish gather to the surface to grab food, and the general domestication time is 3 ~ 5 days. The particle size of pellet feed was 2.5mm in the early stage of culture and 3.5mm in the later stage of culture. Generally, pellet feed is fed twice a day, and the daily feeding rate is 3.5% and 5%. When feeding green fodder, feed 10kg~15kg green fodder per 50kg body weight. The intake of grass carp should be 80% full, and the daily feeding amount should be increased or decreased according to the weather and feeding conditions.

two。 Water quality regulation in the process of culture, because the feed is sufficient and the water quality is more fertile, except for one-time application of base fertilizer 200kg/ mu ~ 300kg/ mu, fertilizer is no longer applied in the process of culture. Maintaining good and stable water quality can ensure that fish ponds do not flood ponds, which is an important work of daily management. We should patrol the ponds twice a day, add fresh water once a week, and pay close attention to the changes in water quality. take effective measures to improve water quality in a timely manner. Water quality management pays attention to "shallow spring, summer surplus and autumn cool". "shallow in spring" means that the water depth of the pond is controlled at 1.0m~1.2m from the end of winter to spring, which is conducive to the rise of water temperature; "summer surplus" refers to the peak period of fish growth in summer, which should be filled with water and flow moderately to form micro-running water, so as to prevent floating heads and floodponds caused by high temperature weather fusion. "Autumn cool" means that the pond is fully loaded in autumn, and the water quality should be adjusted frequently, and the drainage should not exceed 1 pound 4 each time, to ensure that the water quality is refreshing and the dissolved oxygen content is high.

3. Daily management personnel should carefully keep daily records of fish stocking, feeding, prevention and control of fish diseases and fish deaths. Daily management should achieve "four mornings" (that is, early clearing of ponds, early fertilization, early stocking, early feeding), "four looks" (that is, depending on the season, weather, fish condition, water color and feed), and rational use of aerator. Starting from summer, the aerator should be turned on for 2 hours to 3 hours every morning, from midnight to dawn in cloudy and rainy days, and 1 to 2 hours at noon in sunny days, so that the pool water can reach a higher standard of dissolved oxygen content.

4. The season of fish disease prevention and control is generally from April to September, and the peak period is from May to July. In accordance with the principle of "prevention without disease and early treatment with disease", ecological prevention, vaccination and the combination of Chinese and western medicine prevention and treatment should be adopted. Conscientiously clean up and disinfect the ponds before stocking and disinfect the fry ponds to kill pathogens. From April onwards, sprinkle with quicklime 10mg/L~20mg/L to prevent it every 15 days or so. From May to August is the epidemic season of fish disease, 90% crystal trichlorfon 0.3 mg/L~0.5mg/L can be sprinkled in the whole pool to control parasitic diseases, and chlorine dioxide 0.3mg/L~0.4mg/L or bromochlorohydantoin 0.3mg/L can be used in the whole pool to control bacterial diseases. In the later stage of culture, the water quality is very strong, and the algae multiply in large numbers, which can be killed with 0.7ppm copper sulfate.

5. After five months of breeding, all kinds of fish species put in in the first season have basically met the commodity specifications, and all the fish should be caught and listed before the end of May. At this time, around the Dragon Boat Festival, the supply of fresh fish is off-season, and the market price is high. After more than five months of careful breeding, all kinds of fish species released in the second season will meet the commodity specifications by the end of December, and all of them should be caught and listed on the market.

8. Test results

1. The fishery production demonstration and extension pond covers an area of 156mu, with a total annual output of 250.02 tons of fresh fish, of which grass carp production is 184.87 tons, accounting for 73.9% of the total output, and the average survival rate of grass carp is 95.4%. The average yield per mu was 1602.7kg, with an increase of 133t and an average increase of 852.7kg per mu.

two。 The total economic benefit of catching fresh fish is 250.02 tons, the total output value is 1.8247 million yuan, the average output value per mu is 11697.1 yuan, the total cost is 1.0003 million yuan, the average mu cost is 6411.9 yuan, the total profit is 824400 yuan, the average mu profit is 5284.6 yuan. The ratio of input to output is 1 ∶ 1.82, and remarkable economic benefit has been obtained.

IX. Summary and analysis

1. The high-yield and high-efficiency techniques of grass carp culture in ponds in two seasons a year mainly adopted technical measures such as stocking large size fish species, increasing the proportion of grass carp species and famous and high-quality species, reducing the number of low-quality silver carp, feeding pellet feed to strengthen culture and ecological disease prevention, etc. shorten the culture cycle, so that the stocked fish can meet the market specifications after five months of careful breeding, and effectively improve the per unit yield and economic benefits of pond fish culture. It is a good model for pond farming.

two。 For grass carp cultured in ponds, after injection of frozen stem cell attenuated vaccine and "triple" vaccine, the immune effect is obvious, there is no hemorrhagic disease, the "three diseases" (rotten gills, red skin, enteritis) of grass carp are significantly reduced, and the survival rate of culture is greatly improved. the average survival rate of grass carp reached 95.4%, which was more than 25% higher than that of unvaccinated pond grass carp. By using the vaccination prevention method, 810 grass carps are released per mu of pond each year, and the cost is only 60 yuan, which is more economical and effective than the drug control method. The use of immunity to prevent grass carp disease can reduce the residue of drugs used in fish, which meets the standard requirements of pollution-free culture and is worth popularizing and applying in a large area.

3. In the ponds where grass carp are mainly fed with compound feed, supplemented by green feed, and the combination of green feed and concentrate feed, the conversion rate of compound feed is increased, the production cost is reduced, and the period of adult fish culture is shortened. In the mountainous area of northern Fujian, Rain Water is abundant before June, and the local ryegrass and wild grass planted in winter fallow fields are rich in resources, which can be fed mainly with green fodder and supplemented with mixed pellet feed; after June, Rain Water is relatively reduced, the weather is hot, and the grass is insufficient, which is the best period for fish growth, and can be fed mainly with compound feed and supplemented with some green feed. The feeding method of the combination of green feed and concentrate feed can not only reduce the labor intensity of fish culture, but also reasonably solve the contradiction between supply and demand of green feed, promote the rapid growth of fish, and help to develop from traditional rough culture to intensive culture, intensive culture and large-scale culture.

4. The pond mainly raises grass carp with high yield and high efficiency in two seasons a year, and there should be sufficient sources of large fish species. Large fish species should be cultivated according to the proportion of 1 mu fish ponds per 5 mu of adult fish ponds to ensure that the number of large fish species can meet the needs of production.