Hatching management of artificial reproduction of black fish

Black fish is a kind of fish commonly eaten in our country, it is a common delicacy on the dinner table, and its nutritional value is extremely rich, the protein content of black fish is very high, eating more black fish has a certain effect on the wound anti-inflammation of human body, so many women in life will buy black fish to eat after caesarean section.

Hatching management of artificial reproduction of black fish

The fertilization rate, the water quality and whether the dead eggs and seedlings can be removed in time will directly affect the hatching rate. Therefore, the following points must be done well in the process of productive hatching:

1. The operation should be light: prevent damage to fish eggs. When handling fish eggs, use pots, ladles, bowls and other water to move. 2. Keep the water fresh: it is better to keep the water green and contain an appropriate amount of phytoplankton. Stop water hatching every day to replace the water body of 1 beat 3 times 1 move 2, it is best to take the way of drainage while entering, to maintain the original water level. The speed of influent and drainage is slower to prevent the rapid influx of water and the impact of vibrating fertilized eggs on embryonic development. Micro-flow water hatching is also slow to enter the water, adhere to the discharge every day, the surface dirt is generally used to salvage, and the bottom dirt is absorbed by siphon. The egg membrane should be removed in time after the fry comes out of the film to prevent the deterioration of the water quality caused by the deposition and corruption of the egg membrane. Eggs hatched in the hatching pool or left in the original spawning pool should generally change the water once a day, remove part of the old water, inject some new water, and maintain the original water level. It is worth noting that after hatching, it is not advisable to change water too much to avoid excessive changes in water temperature and make the fry ill. In general, on the day the larvae are hatched, the amount of water exchanged in the hatching pond accounts for 60%-70% of the total water, and from the second day to the fifth day, it can account for 80%. 3. Control the occurrence of water mold: it is very important to control water mold infection during the hatching period of fish eggs. At the optimum incubation water temperature, it is also the period of high incidence of water mildew. Generally unfertilized bad eggs are white for more than 10 hours, and dead eggs or moldy eggs must be removed manually in time. When water mildew occurs in the process of hatching, if the number of infection is small, the diseased eggs can be removed; if the white bad eggs account for the majority, the number of infection is large, and the harm is great, they can move downwards.

4. Prevent the sudden change of water temperature: the temperature difference between the fresh water and the water temperature in the pool should not be too large, and the temperature difference in the incubator should not exceed 2 ℃ after water change. For this reason, the newly hatched fish fry ponds should not change too much water; it is best to cover the hatching facilities with shade canopies to prevent direct sunlight and showers, resulting in drastic changes in the temperature difference of the pond water and rain hitting the fertilized eggs. 5. Prevention of hypoxia: the main reason for hypoxia in hatching water is that there are too many organic compounds in hatching water, which lead to high oxygen consumption and hypoxia when these organic compounds decay. The organic matter in the hatching water comes from the water source itself and the dead eggs, dead embryos and dead fish fry are not removed in time. Sometimes due to the use of anoxic groundwater, it is injected into the incubator without aeration. In addition, due to the existence of oil balls in the eggs, when these eggs break for various reasons, these oil balls will be released into the water to form a thin oil seal on the surface of the hatching water. In addition, during the hatching process of the fertilized eggs, the oxygen consumption of embryonic development is particularly high, which will lead to lack of oxygen in the water.

Hypoxia in the hatching water not only affects the hatching, but also increases the number of dead embryos. In addition, the dead embryos of these dead eggs are not removed in time during management, resulting in corruption and rupture, and the release of oil droplets, which aggravates the hypoxia of the water body due to the increase of oil seal and organic oxygen consumption. to form a vicious circle. Therefore, in the management, not only the pollutants in the water should be removed, but also the dead eggs should be fished out in time before the dead embryos are broken to avoid releasing oil droplets. At the same time, when changing water, pay attention to gently change the water layer with oil seal in the surface layer, the operation process should be light and brisk, to avoid egg rupture.

The economic value of black fish

As a valuable freshwater fish with high economic value, black fish is known as "the treasure of fish". Its nutrition is very rich, and meat contains a lot of protein, which is higher than that of chicken and beef. According to the determination, 100 grams of black fish meat contains 19.8 grams of protein, 1.4 grams of fat, 1.2 grams of ash, 57 milligrams of calcium, 163 milligrams of phosphorus, 0.5 milligrams of iron, 77.9 grams of water, and 383.5 kilojoules of calories. Its protein is rich in amino acids. The content of delicious amino acids accounts for 47.36% of the total amino acids, and the content of essential fatty acids accounts for about 16% of the total fatty acids. Therefore, from the point of view of nutrition, black fish is a kind of advanced health food with comprehensive nutrition and delicious meat.

Black fish is used for food, its bone spur is less, and the edible rate is 63%. The edible rate of snakehead is as high as 75.63%. In cooking, black fish meat is smooth and smooth, which is suitable for frying fish fillets, fish scales and edge stove, while snakehead is suitable for cooking and stewing. The fish soup has no fishy smell, strong flavor and loose fish meat. The "rich fish fillet" cooked with black fish is a delicacy famous all over the world.

Used in medicine, black fish has the effect of desilting and nourishing. Eating blackfish after surgery or trauma has the effect of invigorating muscle and tonifying blood, converging and promoting wound healing. Frail patients, mothers and children often eat blackfish for their health. In southern China, especially in Guangdong, Guangxi and Hong Kong and Macao, blackfish is generally regarded as a good tonic for patients and those with weak old larvae. Guangdong's well-known "raw fish kudzu soup", with heat-clearing and detoxification, Sheng Jin to quench thirst, extract poison Shengji and other effects, is very popular with the broad masses of people.

Nutritional value of black fish

1. Blackfish meat contains protein, fat, 18 kinds of amino acids, etc., as well as calcium, phosphorus, iron and a variety of vitamins essential to the human body.

2. It is suitable for people who are weak, hypoproteinemia, spleen and stomach qi deficiency, malnutrition and anemia. Black fish is often regarded as a precious tonic to promote milk and tonify blood in Guangxi.

3. Black fish has the effect of dispelling wind and treating chancre, tonifying spleen and replenishing qi, promoting water and reducing swelling, so there are often parturients, rheumatism patients and children with disease looking for snakehead fish as an auxiliary food therapy in the three northern areas.

4. The vitality index of black fish is 0, but the disease prevention index is 6.41.

The living habits of Blackfish

The survival water temperature of black fish is 0-38 ℃, and the optimum water temperature is 16-30 ℃. When the water temperature rises above 8 ℃ in spring, the black fish often moves in the middle and upper layers of the water; when the water temperature drops below 6 ℃ in autumn, it swims slowly and often lurks in the depths of the water; when the water temperature is too low in winter, it hides at the bottom of the water.

Black fish is a carnivorous fish, and its food varies with the size of the fish. Juvenile fish less than 3 cm feed on chiropods, cladocera and chironomid larvae, while small fish with a body length of 3-8 cm mainly feed on aquatic insect larvae, fly maggots, small fish, shrimp and small tadpoles. Adult fish of more than 20 cm mainly eat carnivorous animals such as small wild miscellaneous fish, shrimp, frogs and so on. When black fish hunt, they do not chase, but hide near aquatic plants or other hidden objects, keep a close eye on the movement around them, and quickly attack and eat their prey when they see fish, shrimp, frogs, etc., passing by.

The growth rate of black fish depends on the quality of the growth environment and the amount of food. Under natural conditions, the body length and weight of 1 winter-aged fish can reach 19-39 cm and 100-750g, and that of 2 winter-aged fish can reach 38-45 cm and 600-1400 g respectively. Under the condition of artificial feeding, the body weight can reach 250 grams in that year and 0.5 kilograms in the next year.

With the continuous development of the aquaculture industry, the breeding industry of black fish is becoming more and more extensive, but the breeding cost of black fish is much higher, but at the same time, the profit it can return is also much larger. Investors can choose their own scale and quantity according to their own actual situation.