Farming technology of Yellow Jaw fish in Hubei Province
_ Li Shenghua
Walsell's yellowtail is a freshwater famous economic fish, its meat is tender, delicious and nutritious, and it is deeply loved by consumers. In recent years, due to the increasing market demand for Wawner's yellowtail and its declining resources in the Yangtze River system, the pollution-free artificial culture of Wawner's yellowtail has great development prospects and market potential.
I. A Biological Introduction to the Yellow Jawfish
The Yellow Jawfish, also known as hard-horned Yellow Lading, Lang Si, Jiang Jaw, Fat Lump Yellow Jaw Fish, etc., is mainly distributed in the main tributaries of the Yangtze River Basin in China and the lake body connected with the Yangtze River. The Yellow Jawed Fish is long in size , with a raised back , a flat thorax and ventral surface , a slightly lateral flattened posterior half , a slender caudal stalk , and a deep forked caudal fin. There are 4 pairs of tentacles, all bluish-black, and the whole body is bare and scaleless. The difference between the Wawner and the yellowtail is that the adult of the Wawnerii is large, and there are also large differences in body color. The yellowtail has a pale grey back and a yellowish belly; the yellowtail has three transverse longitudinal gray-black patches on the sides of the body, a bluish-gray back and a dark yellow belly. Individually, the individuals of the Yellowtail are more than twice as large as the Yellowtail.
The YellowTail is a benthic fish, which prefers to inhabit the slow flow of still water, camp benthic life, likes to inhabit the bottom of the river body during the day, and swims to the shallow shoal of the water body at night to feed, and has a strong adaptability to the ecological environment. It is a meat-feeding omnivorous fish that prefers to feed and move in clusters under low-light conditions. It mainly feeds on branches, copepods, mosquito larvae, water earthworms, snail lions, small shrimps, small fish, fish eggs, bitter vegetable leaves, Malay eye leaves, polygrass leaves, plant roots and decomposition, under artificial breeding conditions, can make good use of artificially prepared pellet feed.
The yellowtail grows faster than the yellowtail, and the male is generally larger than the female and grows much faster than the female. Yellowtail commonly weighs 300-750 g and the largest individual weighs 2500 g. The number of eggs in the Wawnerii yellowtail is 1000-5000, and the fertilized eggs are round, yellowish, sticky, and develop on objects such as aquatic grass roots that sink to the bottom of the ovary or adhere to the nest wall.
2. Fry breeding of Walsh's yellow jaw fish
1. Fry rearing
Fry rearing refers to the process of hatching the membrane and rearing the fry to about 5 cm. This phase takes about 20-30 days.
(1) Cultivation pond. Factory seedlings usually use small flowing water cement ponds, the area of the breeding pond is 10-20m2, the depth is about 0.8m, the depth control of the water is about 0.7m, rectangular and circular, requiring good water conditions, fresh water quality, and strict filtration does not bring in other predators. The bottom of the pool is flat, slightly inclined towards one end of the drain, and the bottom is tiled or smoothed with cement.
(2) Cultivation density. The newly hatched baby fish can be stocked with 8000 -10000 fish/m3, and when the fry grows to about 1 cm, the fry begins to be cultivated in separate ponds, and the stocking density of 1-3 cm fry is 5000 -6000 fish/m3; after growing to 3 cm, the pond is divided, and the stocking amount of fry of about 3-5 cm is 3000 -4000 fish/m3.
(3) Feed feeding. About 65 hours after the removal of the film, the yolk sac gradually disappears, the body color slowly becomes black brown, and from the original gathering at the bottom of the pool to adsorbed on the edge of the surrounding pool wall, the total length of the fish is about 7mm, at this time the fish have begun to feed the bait. Feed feeding should be based on different stages of development of The Yellow Jawfish on the Wahler's, feeding different baits. The open bait for fry is mainly small branches and rotifers. Due to the small size of the fry, the flea thrown can not be large, it is best to filter with a mesh cloth of 40 mesh; in addition, the amount of the fry should be more than less, in order to prevent the fry from self-harm. After 12 days of age, it can be fed to benthic animals such as mosquito larvae, water earthworms, oligochaetes or crushed fish slurry; after 15 days of age, it can be fed broken pellet feed, and the fry can be smoothly converted and grow well. The Yellowtail has a group feeding habit, and when feeding, it is first fed into the pond with a small amount of feed, and when the fry are concentrated, it is necessary to increase the amount of feeding, while eating and feeding. The amount of feeding should be determined according to the size of the fish body, feeding status and water temperature, and generally a small number of times of feeding methods are generally used.
(4) Daily management. The transparency of the breeding pond is controlled at about 30cm, according to the weather and the growth of fish, gradually increase the water level to prevent excessive reproduction of plankton in the pond; once a week, the water should be changed and discharged, the water temperature should be increased when the water temperature is higher than 28 ° C, and when the water temperature is higher than 35 ° C, new water should be injected once a day. Insist on patrolling the pond in the morning and evening, always keep the water fresh, and strictly prevent hypoxia floating heads. If it is found that the fry are active in the middle and upper layers of the water body during the day, most of them are signs of hypoxia, and it is found that the fry are scattered around the shore of the pond, which is a sign of serious hypoxia, and it is necessary to immediately open the aerator and flush the water to increase oxygenation. During the cultivation of seedlings, when the intake of food is suddenly reduced at normal temperatures, attention should be paid to checking whether there are any diseases. Tools used in diseased fish ponds must be sterilized before they can be used to avoid cross-infection and the spread of fish diseases.
2. Fingerling rearing
(1) Fingerling breeding ponds. Watt's yellowtail
The area of the fish fingerling breeding pond should not be too large, 1-3 acres is appropriate, it is required to be close to the water source and the water source is sufficient, fresh and pollution-free, and the pond is equipped with an aerator. Set up a bait table in the pond, the material is bamboo mats, grass mats, color strip cloth and other materials, the area of the bait table per mu of pond is about 6-8m2, and the bait table is fixed with bamboo piles or wooden stakes about 10-20 cm from the bottom of the pond.
10-15 days before the fry are put into the pond, use quicklime 75-125kg/mu or bleaching powder 5g/m2 to sprinkle the whole pond, including the pool wall, after one week of cleaning, inject filtered new water 50cm deep, apply inorganic fertilizer and yeast liquid to cultivate plankton, about 7 days or so can be stocked with fry.
In the cultivation of fry of Wawner's yellow jaws, the use of domestic fish hair pond technology, only focus on the cultivation of zooplankton, ignore the cultivation of benthic animals, and then directly feed artificial feed, due to the small number of benthic animals in the pond, resulting in a serious lack of suitable bait at the juvenile stage, which is the main reason for the low survival rate of fry. In terms of production, the method of replacing benthic animals with green shrimp fry is also adopted, that is, at the same time as the pond is developed, a cage of 1 m2 per mu is set up, and 1 kg of egg-hugging shrimp caught on the same day is stocked in the box, and aquatic weeds are stocked in the cage, and snails, fish and other feed are fed every 2 days. After the shrimp fry hatch, take out the cage and the white-whisked shrimp, let the shrimp fry into the pond, then sprinkle soybean milk for shrimp fry to eat, and sprinkle soybean milk 15-17kg/mu in the pond, once in the morning and once in the afternoon.
(2) Fingerling stocking. Stocking small seedlings of about 2 cm require neat specifications, robust physique, no injury and no disease, swimming agility, and strong jumping. Fry are subjected to strict medicinal bath disinfection before stocking. The stocking density is determined according to the production situation and pond conditions, and the stocking density of the fry is generally large, the stocking density is 8000-10000 fish/mu, and the stocking amount of commercial fish cultured in the short-term breeding to July-August is 4000-6000/mu. When the fingerlings have grown to 8 cm, they can be divided into ponds and then placed in adult ponds to rear adult fish.
(3) Feed and feeding. When stocking 2 cm of seed, the amount of zooplankton in the pond can basically meet the demand for a few days, and the best feed for fish species at 2-3 cm is active feed such as rotifers, copepods, branches, mosquito larvae, water earthworms and so on. As individuals increase, the natural food in the pond decreases, and artificial mixed feed must be fed to meet the feeding needs of the seedlings.
There are three methods of bait preparation: First, the method of production is to grind the small miscellaneous fish and mix some fish flour, silkworm pupa flour, bean flour, wheat bran, third-class flour, etc. into a ball of feed, and the fish can also be crushed into a pulp and then glued with third-class flour for direct feeding; second, the powder raw materials are mixed evenly and then kneaded into a ball; third, artificially combined into processed pellet feed, and then crushed into micro-pellet feed. The latter two preparation methods with bait are: fishmeal 23%, silkworm pupae powder 8%, meat bone meal 8%, blood meal 8%, ferment mother powder 6%, inorganic salt mixture 1.5%, binder 15%. In addition, more farmers use trash fish to grind meat puree and feed them directly into ponds. The general feeding amount is 10% at the beginning of the conversion of feeding habits, and then gradually decreases to 5%-6% of the body weight, feeding 2-4 times a day; feeding 3-4 times a day before 3 cm long, feeding 2-3 times a day before the body length of 5 cm, and then feeding 2 times a day. The nutritional standards for the blend of Wawner's yellowtail are: crude protein 40%-43%, fat 8%-10%, carbohydrates 18%-23%, and cellulose 3%-5%. Feeding feed should achieve "four certainties", and the bait is fed on the bait table.
(4) Daily management. The rearing stage of the fingerlings of the Yellow Jawed Fish is the most prevalent period of fish diseases, during which attention should be paid to observation and various preventive measures should be adopted. The most common disease of the Yellow Jawfish in The Walter's yellow jaw fish at this time is hemorrhagic edema disease, in addition to the pond disinfectant to eliminate bacteria, but also add tetracycline to the bait for feeding, once a day, for 3-5 days.
3. Adult pond culture of Watt's yellow jawfish
Pond culture of waltzmania yellowtail is a new breeding method that has emerged in the past two years, which has the characteristics of small investment, no restrictions on area size, large income and stable production.
1. Pond conditions
The main pond is the cultivation of Wawner's yellow jaw fish, before the stocking of fish species, the bottom of the pond should be leveled, and a pit culvert of about 50 m2, 20-30 cm deeper than the place, should be dug out at the bottom of the drainage outlet, which is convenient for the concentration of adult fish when fishing. Adult ponds are generally 2-3 acres, and the water depth requirements are 1.5-2m. It is required that the water source is good, the water quality is fresh, the dissolved oxygen is rich, there is no pollution, the injection and drainage is convenient, the pool is strong, neat, east-west oriented, and the pool is equipped with oxygenation equipment. Before the fish species descend into the pond, the whole pond of quicklime 75-125 kg/mu is sprinkled with disinfection to kill the pathogenic bacteria and predators in the pond.
2. Stocking density
Stocking density is related to fish pond conditions, environmental factors, fingerling size, culture level, water source and other factors. Fingerlings of about 5 cm size are stocked at 5000-6000 fish/mu, and fry with a size of 6-8 cm are stocked at 4500-5500 fish/mu. When the water quality of the yellowtail to be stocked grows to 7-8 cm, the water quality has begun to become fatter, and at this time, about 200 silver carp and bighead carp are stocked, and the stocking size is 6-10 cm, controlling the water quality of the pond.
Fingerlings are strictly sterilized at the time of stocking, usually bathed in a 3% salt solution before being placed in ponds.
3. Feed feeding
The feed of adult yellow jawfish on the Watt's scale has two types: pure animal feed and artificial compound feed. Pure animal feed includes small trash fish, shrimp, aquatic earthworms and so on. Generally, small fish and shrimp are directly fed by processing and crushing into fish slurry, and small trash fish and shrimp can also be mixed with plant powder feed after processing and grinding into a pulp.
Artificial compounds: The nutritional requirements for commercial fish compounds of Wawner yellowtail are 40%-42% crude protein, 7% - 9% fat, 18% -21% carbohydrates, and 5%-6% cellulose. The animal raw materials of the commercial fish feed of the Yellow Jawfish are fishmeal, silkworm pupae, meat bone meal, feather powder, blood meal, bacterial protein powder, yeast, etc.; the plant raw materials are soybean cake, cotton cake, corn and wheat flour. The feed is crushed into powder by 60 mesh. Its adult fish feed formula is 36% of fishmeal, 8% of silkworm pupae powder, 3.5% of feather powder, 8% of meat and bone meal, 5% of blood meal, 5% of feed yeast, 10% of soybean flour, 3% of corn flour, 18% of wheat flour, 0.5% of binders, 1% of vitamin blends, and 2% of inorganic salt additives.
The daily feeding amount is determined by the relationship between the overall weight and water temperature of the pond Wawneret yellow jaw fish, and the feeding amount accounts for 1.5%-2% of the body weight when the water temperature is 10 °C-15 °C; when the water temperature is 15 °C-20 °C, the feeding amount accounts for 3%-4% of the body weight; when the water temperature is 20 °C-32 °C, the feeding amount accounts for 5%-6% of the body weight.
Feeding methods are "four certainties" and "four looks". The so-called "four certainties", that is, when feeding feed, it should be timed, fixed, qualitative and quantitative. Feed 2-3 times a day, feed on the food table, the daily feeding amount of 3%-5% of the weight of the pond fish. The so-called "four looks" means that after mastering the daily feeding amount, it is necessary to determine the actual feeding amount by looking at the season, looking at the weather, looking at the water quality, and looking at the eating and activity of the fish.
4. Daily management
The daily management of ponds mainly includes technical measures such as feeding feed management, water quality management, and fish disease prevention and control.
Feeding feed must be even, sufficient and good. The quality of water quality management also directly affects the growth of the Yellow Jawfish. If the dissolved oxygen is sufficient and the water quality is fresh, it can provide a good water environment for its growth. Adding new water to the adult pond can increase the amount of dissolved oxygen in the water and maintain excellent water quality.
The daily management of the pond must be meticulous and meticulous, often lasting. The scope of management mainly includes feeding feed management, water quality management, daily management and other technical measures such as fish disease prevention and control.
Fourth, the disease control of Wawner yellow jaw fish
In the process of farming, strengthening disease prevention and control is an important measure to improve production and economic benefits. It is necessary to particularly advocate doing a good job in daily aquaculture management and adopting comprehensive preventive measures in order to grasp the initiative in preventing and controlling fish diseases. Walesian yellowtail is a scaleless fish, more sensitive to various drugs than scaly fish, the concentration of medication must be carefully grasped, the amount of use must be lower than the conventional dosage, and after the medication must have a special person to monitor the fish situation, after 3 hours to the fish pond a large amount of water, in order to prevent chronic drug damage. Common diseases of the Yellow Jawfish are:
1. Enteritis disease
Symptoms: The abdomen of the sick fish is enlarged, the anus is red and swollen, the abdomen is lightly pressed, there is yellow mucus flowing out of the anus, and the sick fish swims alone. The abdomen of the fish is cut open, and the esophagus and foregufe are congested and inflamed in the mild cases, and the foregut is inflamed with light red in severe cases, and the blood is thick and congested with the intestinal tract. Enteritis mainly endangers fish species and adults.
Prevention and control methods:
(1) The pond should be thoroughly cleared and disinfected, and the fish should be bathed and disinfected with 2%-3% salt solution before the fish species descend the pond.
(2) Do not feed moldy and spoiled feed, the active bait should be disinfected with 2%-3% salt solution; regularly add 1% salt or add 0.1% fresh garlic juice to the compound feed.
(3) The whole pond is sprinkled with bleaching powder to make the pool water appear at a concentration of 1g/m3; fed sulfaguanidine bait, every 100kg of fish is used for 10g on the first day, and halved the next day. Continuously for 6 days for a course of treatment, or add 40-100 g of oxytetracycline per 100 kg of feed for 5-7 days.
(4) Add 1kg of fresh pine needles and 150g of salt to every 50kg of bait and mix the feed for feeding for 5-6 consecutive days.
2. Water mold disease
Symptoms: Water mold parasitizes fish wounds, grows inward and outward, spreads and spreads, like gray-white cotton wool. Sick fish swim abnormally and restlessly until their muscles rot, they lose their appetite, and they die of thinness. Water mold disease seriously endangers hatched fish eggs and wounded fry and adult fish on the surface of the body, and the disease is most likely to occur in early spring and winter.
(1) Clearing the pond with quicklime can reduce the occurrence of this disease.
(2) In the process of fishing, transportation and stocking, try to avoid injuries to fish bodies and grasp reasonable stocking density.
(3) Soak the diseased fish with table salt and baking soda mixture.
(4) For the fish eggs in hatching, they can be washed and disinfected with 8-10g/m3 iodide trioxygen solution for 8-10 seconds for 2 consecutive times.
3. Oblique tube worm disease and wheel worm disease
Symptoms: The gills and skin of the fish body are parasitized by a large number of insects, and the sick fish are isolated, head down, tail up, upside down on the water surface or lying on the side under the water, breathing difficulty, and soon death.
(1) Thoroughly clear the pond with quicklime to prevent the occurrence of this disease.
(2) Wash the fish body with 1 -2g/m3 copper sulfate solution.
(3) Sprinkle the whole tank with 0.4 -0.5g/m3 copper sulfate and ferrous sulfate compound.
4. Nutritional diseases
Symptoms: Too much or too little nutrients in the feed, denaturation of feed ingredients or insufficient energy, can cause nutritional diseases of the Yellow Jaw fish. Common are fatty liver disease, vitamin deficiency and so on. Sick fish have enlarged liver, pinkish white or yellow color, large gallbladder, black bile, and pale pancreas. Sick fish die sporadically, and the first to die is the largest individual. Prevention and control methods: improve feed formula, improve feed quality, and appropriately increase the amount of vitamins and inorganic salts.