60 ~ 70 days after hatching, the fry can reach 3cm. At this time, most fry have completed metamorphosis and gradually turned to benthic life. In order to improve the quality of cultivated seedlings, it is necessary to transfer to the intermediate cultivation stage. 5cm or more can be used as commercial seeds for breeding. Soak the sterilized seedling pond with bleach solution before releasing seedlings, and add filtered seawater after cleaning. For seedlings with a total length of 3 ~ 5 cm, the seedling density is 1000 ~ 2000 ㎡. During the breeding period, the feed requires balanced nutrition, and high-quality compound feed or self-made soft pellet feed can be selected. Feed 8 ~ 10 times a day at the initial stage of feeding, and gradually decrease to 3 ~ 4 times as the fish grow up. In order to prevent residual bait pollution, the pool water must be drained after each bait feeding, the precipitated residual bait and feces must be removed, and the oil film must be removed. The water exchange rate is 8 ~ 10 cycles per day. In general, the survival rate of young fish from initial incubation to commercial seedling stage is 10 ~ 20%, which can reach about 30%.
Out of the pond: the larvae of Duobao fish are generally discharged and collected out of the pond, so it is necessary to avoid damage to the larvae out of the pond when operating, and to test the quality and specifications of the larvae out of the pond.
Transportation: The transportation modes of fry are box-type or barrel-type container inflatable transportation and running boat transportation, which can be selected according to the specific situation. The water temperature and salinity of transportation water can be adjusted in advance according to the requirements of developing water environment. Seedling transportation should stop eating 1 day or more.
Fish stocking
To control and adjust the culture density, it is necessary to adjust the culture density according to the water exchange capacity of the pool and the growth of fry in actual production. When controlling the breeding density, the following factors should be considered:
When the exchange capacity of pool water is less than 6 ranges per day, the density should be reduced appropriately; When the daily trading volume is greater than 10 intervals, the density can be appropriately increased; The density can also be increased or decreased according to the amount of dissolved oxygen in the monitored water.
Fish are sampled and weighed every month to decide whether to adjust the density.
Make full use of the culture area, which will not slow down the growth rate of fish in some culture ponds because of over-stocking, nor waste the culture area because of low stocking density.
In order to ensure that excessive stress reaction will affect the growth of fish, adequate plans should be made every time the pond is divided and tang qian is dumped, so as to ensure that the fish will be stable in one pond for at least a period of time before the pond is divided.
Feeding and feeding
The basic requirement of Duobao fish for feed is high protein and medium fat. Compared with other carnivorous fish, its demand for fat is slightly lower. If you feed high-fat feed for a long time, it will reduce the function of the liver. In order to make turbot grow healthily, it is necessary to feed turbot with feed suitable for each growth stage. The content of protein in feed is required to be 45-56% at seedling stage (including juvenile fish stage); In the growing period, the content of protein in feed is 45-50%. Duobao fish has a low demand for fat. The fat content in feed at seedling stage is about 10%, and at growing stage it is 10 ~ 13%. The optimum C/P ratio (energy-protein ratio) at seedling stage is about 65%. With the growth of fish, the C/P ratio of feed in growing period increased to 65 ~ 76%; The C/P ratio of feed used in tang qian is 80%.
The feed used in the culture of Duobao fish should be suitable for the nutritional needs of different growth stages, and contain appropriate amounts of vitamins, minerals and highly unsaturated fatty acids. The feed used should be easy to feed, and the feed particles should be well formed and not easy to disintegrate in water. When buying feed, check whether the feed label is marked with the following contents: Should it be marked? Does this product meet the hygienic standard of feed? Text to indicate that the product conforms to the provisions of GB 13078; Indicate the guaranteed value of the main components, that is, the contents of crude protein, crude fiber, crude ash, calcium, total phosphorus, salt, water and amino acids; Indicate the standard number, production license and product approval number of the product; Specification, model, net weight, production date, shelf life, manufacturer's name and address, etc. In order to prevent pathogenic organisms from being brought into fish ponds from feed, it is suggested that wet pellet feed and any fresh materials should not be used in industrial farming.
Because turbot belongs to a temperature-changing animal, its food intake varies greatly at different water temperatures. Generally, the daily feeding rate at seedling stage is 6 ~ 4%, about 2% when it grows to 100g, and about 1 ~ 0.5% when it grows above 300g.
Scophthalmus maximus 1 Prevention and treatment of diseases. Observation and detection
Regularly observe the feeding, swimming, growth and development of cultured fish with naked eyes, find sick fish and dead fish in time, take them out for anatomical analysis and microscopic observation, analyze the reasons and record them. Burn and bury dead fish.
2. Prevention and control principles
Adhere to the policy of putting prevention first, and take comprehensive measures such as light control, temperature regulation, water quality treatment, use of safe disinfectants, and increase of tap water.
3. Drug use
The drugs listed in the announcement of the Ministry of Agriculture 193 are strictly prohibited in the whole breeding process.
Growth and survival rate of cultured turbot;
The growth rate and culture effect of Duobao fish are closely related to fry quality, feeding water temperature, feeding density, water exchange rate, feeding mode, feed used and feeding method, and any one of them can not be ignored. When the water temperature is lower than 7℃ or higher than 22℃, the growth of turbot will slow down or not grow. In the range of water temperature 10 ~ 22℃, the growth rate increases with the increase of water temperature. Other things being equal, the higher the feeding density, the slower the growth; The higher the water exchange rate, the faster the growth rate; The feed has balanced nutrition and high conversion rate, which is beneficial to growth; The suitable temperature period is long and the growth is relatively fast. Under good feeding conditions, before the weight reaches100g, the body length of turbot grows slowly, but the daily weight gain is faster. When the weight reaches100g, the weight growth rate is obviously accelerated. The average daily weight gain rate of turbot in two years was 4.82g/day, and the highest rate was18g/day, in which the average daily weight gain rate in the first year was about 2.23g/day, and that in the second year was 6.84g/day. Penglai City, Shandong Province 1997
For example, the average weight of turbot cultured for 250 days is about 500 grams. Breeding for about 390 days, the weight is about 1000 g; Breeding for 520 days, weighing about 2000 grams; After 600 days of feeding, the weight reached 2500 grams. At the same time, the growth rate of Duobao fry is also very different. The largest adult fish can reach 4300 grams after 6 13 days of culture, and the smallest is only 550 grams. The seedlings were introduced from 65438 to 0998, and cultured for 247 days, with an average weight of 693 grams, with the largest individual of 820 grams and the smallest individual of 300 grams. It can be seen that the weight gain of Duobao fish can reach about 1 1,000 g in the first year, and the growth rate is obviously accelerated in the second and third years, and the weight gain can exceed 1 1,000 g/year. At the same time, it is very important to choose good fry, optimize breeding conditions, use high-quality feed and prevent diseases, which is very important for raising treasure fish and improving breeding efficiency and benefit.
In autumn and winter (August ~ 65438+February), when the water temperature is about 18℃, iridovirus is usually infected by eating bait fish with virus.
Ill fish gill silk anemia, dark gray; The muscle tissue at the root of the fin and the tissue along the spine are congested, and in severe cases, subcutaneous diffuse bleeding and redness appear all over the body; Thin blood and poor coagulation; The gastrointestinal wall showed punctate bleeding; Decreased food intake, decreased vitality, difficulty breathing and scattered distribution. There are few deaths in the initial stage of infection, but they die soon after obvious symptoms, which belongs to subacute death. It occurs from seedling stage, breeding stage to parent fish breeding stage, and the epidemic range is all over the turbot culture area along the coast of Shandong Province, with a high cumulative mortality.
Prevention is the key to this disease. Avoid feeding frozen or stale miscellaneous fish to prevent viruses and other pathogens from entering the culture system. Once sick fish are found, they should be isolated in time. Dead fish should be buried or burned, and the breeding system should be thoroughly disinfected with bleaching powder or potassium permanganate. There is no completely effective treatment for this disease.
The economic value of Duobao fish is its high colloidal protein, delicious taste and rich nutrition. It has a good moisturizing and beautifying effect, can tonify the kidney, strengthen the brain, and help the yang to refresh. Regular consumption can nourish and improve people's disease resistance. China is steamed and stewed, and it is also a good material for making sashimi. Its fish head, bones, skin and fins can also be used as soup.
This kind of fish is no stranger to Europeans. Species introduced from China are found in England, France and Germany. And the ancient Romans had long regarded it as delicious and named it? A pheasant in the sea? The name of. In Europe, because of its tender meat and delicate taste, it is a good raw material for making fish steaks and fillets, which has a great momentum of crowding out the steak market.
The general eating method of Duobao fish is whole steaming, which belongs to a very traditional Cantonese style. Europeans like to make treasure fish? Fish steak? . Some restaurant chefs will cook the meat of Duobao fish first and then steam the fish. In the sauce, they even use the red wine sauce commonly used in western food with Japanese cooking sauce. When serving, each Duobao fish steak is placed on a white porcelain platter, poured with red wine juice, mixed with exposed bamboo shoots and other condiments, which is as exquisite as a work of art. When eating this dish, everyone gets a fish steak. In addition, everyone has a set of knives and forks, just like in a western restaurant? Saw? Just eat steamed turbot, and the best is shark fin.
Today's famous dishes are: steamed turbot with chopped pepper and black bean sauce, steamed turbot and so on.