Freshwater valuable fish, "fish in the treasures", is a comprehensive nutrition, meat flavor of high-level health care, has always been regarded as the recovery from illness and the old and young people's physical weakness of the nourishment of the treasures. Currently, blackfish farming benefits significantly, has become one of the popular aquaculture.
One, pond conditions
The pond should be selected for good lighting, ventilation, inlet and outlet convenient, the pH value of the water should be neutral or weakly alkaline, the transparency of about 30 centimeters, the water depth of 1.5 to 2 meters, inlet and outlet must be set up to prevent the escape net, the bottom of the pool for the mud, an area of 2 to 4 acres of ponds.
Two, fish species selection
Blackfish farming should be put in large-size high-quality fish species, specifications in the 10-15 centimeters or so, 2000 to 2500 tails per acre, and can be set 200 to 300 tails of large-size chub species.
Three, baiting technology
1. Fresh bait: blackfish is a carnivorous fish, mainly small fish, freshwater and seawater small fish can be. At the early stage of aquaculture, for the larger specification of wild fish after chopping and feeding, the daily feeding amount is generally about 5% of the total weight of the fish.
2. Artificial feed: blackfish can also be fed with artificial bait, the formula is: 70% of minced fish and shrimp, 20% of soybean meal, yeast 5%, the rest of the multi-vitamin mineral salts, growth promoters and antimicrobial agents. Baiting should be done at regular intervals, positioning, quality and quantity. Baiting 2 times a day, that is, once in the morning and once in the afternoon, when feeding is strong, you can feed again in the evening.
Four, daily management
1. Pool patrol: every morning and evening to patrol the pool, carefully observe the blackfish feeding and activities, pay attention to the water quality changes, and find problems in a timely manner.
2. Water change: once you find too much bait or aging water, you can inject new water and discharge old water to keep the water fresh and promote the normal growth of blackfish.
V. Disease control
1. 10-15 days before the fish species into the pond to clean the pond disinfection. Dry pond disinfection, generally 60-75 kg of quicklime per mu; with water pond disinfection, generally 1 m water depth 120-150 kg of quicklime per mu.
2. Fish disinfection, such as in the market to buy fish species, must be disinfected before the pond, available 2.5% to 3% of the salt water to soak the fish body 15-20 minutes.
3. Regular disinfection of the food table, can use bleach solution for splashing.
4. Although the blackfish is more resistant to disease, it is also prone to diseases after high-density breeding, mainly hemorrhagic disease, rotting skin disease, mange disease, etc. The treatment is carried out by a combination of internal and external methods, and 100 grams of chlorine dioxide per acre per half-month is used to splash the whole pool with water, and Enrofloxacin is taken internally.
Stocking techniques
Parental fish pool selection: the size of the stocking pool should be based on the number of each reproduction. For example, if you can breed 50 to 70 pairs at a time, basically according to the principle of stocking 1 pair for every 10 square meters, then choose a pond of 0.6 to 1 mu; if you can only breed 30 to 40 pairs at a time, then choose a pond of 0.3 to 0.6 mu. The main reason is that when the gonads of the parent fish have matured, it is best to catch and catalyze once, and it is not advisable to catch them several times. Because snakeheads pulling net fishing starting rate is low. Generally, the pond water is drained to catch, which is a great stimulus to the parent fish. The pond is too large, the parents are overly concentrated, many times dry, many times fishing, not only a waste of manpower, material resources, and many times strong stimulation, will cause gonadal degradation of the parents, affecting the effect of the latter batches of catapults. Therefore, the principle of selecting the size of the parental pool should be taken to match the stocking amount of each pool and the amount of each reproduction. Pool depth of 1.5 to 2.0 meters is appropriate, irrigation 1.0 to 1.5 meters, the ridge above the surface of the water more than 0.5 meters. If the pool depth is only 1.0 ~ 1.2 meters, the water can still be filled to 0.8 ~ 1.0 meters, surrounded by a bamboo fence or old fishnet fence, 1.5 meters high, to prevent snakeheads from jumping out of the pond.
Preparation for stocking: before stocking, make a good fish pond cleaning and disinfection work, generally use dry pond disinfection. If the silt is too thick, dig out too much silt, leaving about 20 centimeters. Use 50 to 75 kg of lime per mu to clear the pond, 10 days after flooding can be stocked with parent fish. Raise a small amount of water peanuts, water hyacinth and other aquatic plants in the pond for snakeheads to hide in the habitat, and at the same time have the role of anti-escape. If the selected parent fish is wild, the parent fish pool can be stocked with some small mixed fish, the size should be small, not too large.
Parental fish stocking points: the key to parental fish stocking is the density, time and male-female ratio. Density is generally stocked at 100 to 150 kilograms per mu, up to 200 kilograms. Should be based on the size of the specifications of the parent fish, generally in the 150 to 250 tails or so. Density should not be too high or too low, too high will affect the activity space of the parent fish, too low is not easy to tame, especially the wild parent fish, these will affect the gonadal development of the parent fish. The time schedule is in September. the water temperature in September is 25-30℃, from high temperature to cool gradually, which is conducive to the cultivation of the parent fish before overwintering, and the feeding is more vigorous. Parental fish through the fishing, transportation, especially wild parental fish to the new ecological environment, often do not forage. The stocking in September can still be tamed through more than two months, so that it adapts to the new environment active feeding, recovery of physical fitness, and can promote the development of the gonads, improve the female fish egg carrying capacity. When stocking, males and females are basically mixed according to the ratio of 1:l. At this time, it is more difficult to distinguish between males and females. At this time, it is difficult to distinguish between male and female, so it can only be said that the basic stocking number is slightly larger than the actual need. Parent fish in the pool before the use of 2% to 3% of the salt water disinfection or 30 mg / kg of formalin solution bath for about 10 minutes, after disinfection into the pool has been prepared for the parent fish.
Specialized breeding techniques
1. Fish pond selection fish pond requires ventilation to the sun, adequate water supply, an area of 1 mu to 5 mu, water depth 1 m to 1.5 m, surrounded by planting some water floats or aquatic peanuts, and in the lower part of the mesh enclosure, which prevents the escape of the fish, but also can be hidden, shade, to create a good ecological environment, conducive to the growth of the fish.
2. Pond disinfection fish pond selected, the first pond water drainage, every 667 square meters with lime 140 kg ~ 150 kg of water, the whole pond evenly sprinkled, and rake and other tools to turn the silt, fully disinfected. A week before the stocking of fish species, the pool water injection to a depth of 1 m, and the application of appropriate fertilizer to fertilize the water quality.
3. Fish stocking fish stocking sources generally have two kinds, one is wild, one is artificial breeding. But no matter which source of fish species, before the pond should be screened, will be basically the same specification of fish species with 3% to 5% of the salt water bath for 5 minutes to 10 minutes, and then into the same fish pond. Stocking density depends on the water source, injection and drainage conditions, bait fish sources, etc. In general, 3 cm to 5 cm long fish species, 667 square meters stocked 6,000 to 10,000; 10 cm to 15 cm long fish species, 4,000 to 6,000; 20 cm or so of the fish species, stocking of about 2,000. If the water source, injection and drainage conditions are good, adequate sources of bait fish, stocking density can also be appropriately increased a little.
4. Bait feeding artificial intensive blackfish, mainly low value fresh small fish and shrimp as the main bait. Because of the wild or some artificially bred fish species are eating live bait, so the fish species should first stop feeding for a day or two after the pond, and then every morning along the pond around the feeding of the appropriate amount of dead bait for domestication, and then gradually moved to the pond a feeding. Fish eating dead bait habit, every day at 9 a.m. and 4 p.m. each feeding 1 time, the daily bait for the fish body weight of 5% to 10%, and according to the weather, water temperature, growth, feeding and other flexible control.
5. Daily management of blackfish in natural water bodies or rarefied situation is not easy to develop, but in the case of artificial intensive breeding, if the prevention and treatment is not appropriate, it will be outbreaks of fish disease, and cause serious economic losses. From the author's several years of practice, the common diseases of the fish are water mold disease, rotting skin disease, ascites disease, gill disease and so on. If the prevention and control measures are appropriate, the fish seldom develops or does not develop. Therefore, in the process of fish farming, you should always check the water quality, fish conditions, salvage residual bait, to prevent escape, etc., found abnormalities, to be dealt with in a timely manner.
6. Catch the big stay small, timely market because the fish is fierce carnivorous fish, bait will kill each other when there is a shortage of bait, so every 1 month or so, we have to catch the big stay small 1 time. If there is a big difference in specifications and the number is large, it can be raised to other fish ponds or net boxes of the same specification. When the market price is good, you can reach the commercial specifications of the adult fish on the market for sale. In this way, both can be sold at a good price, but also conducive to the growth of small-size fish. [2]
Artificial reproduction
1.1 Pond conditions
The test with the parent fish pond, breeding pond, breeding pond are east-west rectangular pond, an area of 2 acres/only, 1.5m deep, the bottom of the silt 20cm.
1.2 Catalytic incubation equipment
The facilities are the use of the four big fish reproduction with the equipment, spawning pool for the circular, diameter, 1.5m deep. 8m, 1.5m deep fry hatching equipment is a water-throwing hatching tank, each tank contains about 500kg of water, water filter tank cover for 60 mesh; nests are brown pieces and mussel shells.
1.3 Parental fish selection and cultivation
Parental fish purchased in the field near the river, lakes in the natural catch, from March 1-10 to purchase and transport back to the parental fish 61kg, more than 2 winter age, specifications for the 80g / tail or so, the body shape is normal, disease-free and injury-free. Purchased fish in the pond to cultivate, water temperature of 15 ℃ or more, feeding a small amount of small fish and shrimp, snails and clams, bean cake, etc., and frequent observation of the pond, the appropriate filling of new water.
1.4 Identification of male and female parental fish, ratio and catalytic incubation
Identification of male and female fish: female fish are significantly smaller than male fish; female fish have graphic urinary orifices and almond-shaped germinal pores, the abdomen is inflated and soft at maturity, the germinal pores are slightly infrared flipped; males have only one cloacal pore. Male-to-male ratio and spawning: The male-to-male ratio of the parent fish is 1:1.2. Pond natural spawning without injection of oxytocics, in early April the water temperature reaches 18 ℃, found that the sand snakeheads in the pool side of the upper layer of the water body swimming around, that is, in the pool side of the cloth brown piece and hanging a number of large mussel shells, and injection of water to make the pool water is micro-flow in order to stimulate parental estrus, so that it is in the brown piece and the mussel shells in the natural spawning. Parental fish spawning in the spawning pool, injection of ovotropin 2 (LRH-A) and chorionic gonadotropin (HCG), two injections, the injection site for the base of the thoracic bursa, the first injection of LRH-A at a water temperature of 19 ℃ in April 6 every year, the second injection of LRH-A mixed with HCG at an interval of 12 hours. A and HCG mixture of drugs, after injection, put in the spawning pool, with micro-flow water to stimulate the parent fish estrus, and laid brown pieces and large mussel shells, so as to allow their natural spawning. Hatching: Fertilized eggs are light yellow, round. The egg membrane is transparent and sticky. After the end of spawning in the ponds and spawning pools of the parent fish, timely remove the brown pieces with fertilized eggs and mussel shells, and gently wash away the mud and dirt, move to the hatching tank, and hang the brown pieces and mussel shells in the water.
1.5 fry cultivation
Fish fry out of the membrane 3 days after the appearance of the waist point, the fry can be almost swim, can be counted out of the tank, into the clean and applied fertilizer pond, pond water depth of 70cm; fry early openings bait for the rotifers, small branches and copepods larvae, etc. (mainly rely on the application of fertilizer cultivation), supplemented by the feeding of egg yolks, fish slurry, soybean paste, etc., feeding 3-4 times a day. -4 times a day, and regularly determine the survival rate, growth rate.
2 Results
2.1 Determination of gonadal development and egg production
From March 1st to March 10th, the fish were purchased to the early April spawning, and in one month, it was found that the gonads of the snakeheads were still in the Petri dish - IU stage of development in the early March to mid-March when the water temperature was below 15℃, and when it came to the early April, the gonadal development was still in the Petri dish - IU stage of development; And when the water temperature rose to above 18℃ in early April, the gonads quickly developed to the V stage (the gonadal development rhythm of male and female fish was basically the same). Determined by autopsy, 55 ~ 115g body weight of female Shatangshan absolute egg carrying capacity of 1100 -3500.
2.2 Catalytic incubation
This experiment*** was divided into three batches of catalytic incubation, the first batch of pond spawning incubated by the hatchery tank, 196 groups of production, fertilization rate of 85%, hatch rate of 43%, out of 118,000 tails; the second and third batch of spawning in spawning pond spawning, hatchery tank hatch, the commissioning of the parent fish were 67 groups, 38 groups, the rate of catalytic incubation of 64%, 79%, the rate of fertilization for 78%, 87%, respectively, out of the eggs. The spawning rate was 64% and 79%, the fertilization rate was 78% and 87%, and the fry were 2.7 million and 2.6 million respectively. Parent fish put into this test *** 30l groups, *** 17.1 million fry. Parental fish in the pool is not put into production of about 40 groups of parents in April 30 every year to check, most of the abortion or half abortion.
2.3 Seedling Cultivation
Since April 17th ~ 21st after the successive emergence of seedlings, counting 17, 10,000 tails, so the people 1 only 2 acres of pond cultivation, after 1 month of cultivation, the summer flower specifications up to 2-3cm in 8 only 16 acres of pond breeding, the bait is mainly soybean cake paste, small fish, etc., the daily baiting amount of 5 percent of the pond carrying fish. The daily baiting amount accounts for about 5% of the fish carrying capacity of the pond, and at the same time do a good job of pond inspection, water quality regulation and other management work. After 6 months of feeding, to November 12 net check, measured its specifications between 8 ~ 11cm, weight between 12 ~ 16g / tail, its number of estimated 120,000 tails, the survival rate of 71%, the total production of 1,680kg.
Farming site
1, fish pond conditions. Specialized fish pond size is not limited, but generally 667-1 334m2 is appropriate for ease of management, the maximum not more than 2000m2 is good. Water depth of 1-1.5m, the bottom of the pond is best for mud. Water supply should be sufficient, the pond's usual equipment such as water inlet, outlet and so on should be complete, the water quality should be neutral or alkaline. The pond should be thoroughly disinfected, usually 10-15 days before stocking. Pond disinfection should be selected on a sunny day, divided into dry ponds and ponds with water, commonly used drugs are quicklime, such as dry pond disinfection, generally 50-75kg of quicklime per 667m2, with water pond disinfection, the general water depth of 1m per 667m2 with quicklime 125-150kg. 100cm wide water lily, so that in the summer when the water temperature is high, for the shade of the sun, easy to fish summer and hide, but also to obtain the purification of water quality, favorable to the growth of fish.
2, fish stocking. To make specialized fish to obtain a high yield, fish species must be put enough. General 667m2 put 6,000 or so, if the water quality is good, the depth of 1.5m or more, as long as the management is good, feed enough per 667m2 can put 8,000. But no matter what time stocking, put the specification of the fish fry should be neat and consistent. In addition, attention should also be paid to the quality of the fish species, choose a robust body, scales intact, swim lively normal, no damage to the good. In addition, in the pond specializing in fish, can also be mixed with a small amount of silver, bighead, carp and other fish, which can achieve the control of pond water quality, and increase production, improve economic efficiency. But the mixed domestic fish should be greater than the individual fish species of more than 1 times the appropriate to avoid being eaten by the fish mutilations, such as put 6cm of fish species, mixed with the length of the domestic fish species should be more than 13cm. [3]
Owlfish reproduction
2-year-old osprey sexual maturity, at this time, the body length is generally more than 20 cm, weighing about 500 grams, in China's southern China from April to mid-September for the spawning period, May-June for the spawning period; Central China and East China spawning in May-July to June is more concentrated. The water temperature during the spawning period is about 20-30℃.
Prior to spawning, the female and male fish build a 1-meter-diameter "fish nest" with their mouths in the lush grassy area, and spawn in the quiet morning before sunrise, with the female fish approaching the surface of the water under the fish nest, and lying on her back with her abdomen upward. The body slowly shakes and spawns, and then the male ejaculates in the same supine position. When spawning, the parent fish feels very sensitive and immediately stops spawning when it encounters external interference.
The amount of eggs carried by the fish is about 20,000 per kilogram of body weight, and the eggs are matured once and produced in batches. Output of eggs floating in the nest, the temperature at 26 ℃ by 36 hours hatch out, 30 ℃ when 32 hours hatch out. Freshly hatched fry body length of 3.8-4.3 millimeters, 9 millimeters long when they began to feed. When the young fish grow to 4-5 centimeters, began to live independently, the parent fish also left the young fish group, and sometimes also eat the young fish away from the group. The otter grows rapidly, and in pond culture, the age 1 fish weighs 100-500 grams, and the age 2 weighs 500-1000 grams. It grows faster when the water temperature is above 30℃, and grows slowly when the water temperature drops below 10℃. [4]
Culture status
There are seven species of snakehead fishes*** in China, and they are snakeheads, spotted snakeheads, moon snakeheads, broad-fronted snakeheads, striped snakeheads, threadfinned snakeheads, and long-bodied snakeheads. Among them, only snakehead is a widespread species, distributed in the country's major water systems, the production is also the largest, snakeheads, snakeheads and wide-fronted snakeheads are only distributed in South China, including Taiwan and Hainan Province; while snakeheads, snakeheads and long-bodied snakeheads are quite rare, the distribution area is very narrow, only in the Nujiang River, Lancangjiang River in Yunnan Province, the economic value of the small. It is customary to refer to the snakeheads as the blackfish, blackfish (northern and eastern China), caiyu (Hubei and Hunan), shengyu (Guangdong and Hong Kong), and wuzhang (southwestern China), in addition to the names of zebrafish, filial piety fish, snakehead fish, and wenyu.
Sichuan Neijiang Jianglong Aquaculture Specialized Cooperative, overblown white snakehead, nothing but to enhance the price of white snakehead, pure speculation, I hope that you do not fall for it, and I hope that all the farming friends can tell their friends and relatives about this news, do not be cheated by it! Analyzed from this perspective, the market for white snakeheads is also coming to an end, and I hope that farmers will be careful with it when choosing breeding varieties.
Snakehead snakeheads have extremely strong vitality and adaptability to the environment, whether it is lakes, reservoirs, rivers, streams and ditches, ponds and weirs or paddy fields, channels, and even swamps, stagnant pools, and depressions that are difficult for fish in general to survive, are able to grow and reproduce. Their growth rate is also relatively fast, in line with the production requirements of "first year fish species, two years adult fish". Channa has a high meat content rate and no intermuscular spines, which makes it one of the most popular fish for young and old alike. It is measured that every 100 grams of fresh fish meat contains 19.8 grams of protein, 1.4 grams of fat and 1.2 grams of sugar, which is a typical high-protein, low-fat health food. According to medical records, snakeheads also remove blood stasis and blood circulation, nourish and strengthen the yang, collect the muscle to produce fluids, cold temperatures and other pharmacological effects, in Southeast Asia and China's two, Hong Kong, Macao and Taiwan has always been regarded as a delicacy and tonic, so it is worth a lot of money. In addition, unlike other fish, snakeheads are not easy to die after leaving the water, and the muscle is not easy to rot and deteriorate after death, so it is more convenient for long-distance transportation and processing.
The mu output of blackfish is nearly 20,000 pounds, which is 10 times that of the four major fish, and the price per catty is about 12 yuan, which is about twice that of the four major fish. What's more, the culture of blackfish in Chongqing and Sichuan is basically zero, and at least 20 million pounds must be introduced from Guangdong, Hubei and Hunan every year.