Factory breeding technology of round-spotted flounder in Tianjin area
Fund Projects: Modern Agricultural Industry Technology System Special Project (CARS-47-Z1), Tianjin Modern Industrial Technology System - Aquatic Products - Marine Fish Breeding Position ITTFRS2018045, Tianjin Agricultural Science and Technology Achievement Transformation and Promotion Project - Integration and Demonstration of Factory Breeding Technology of Round Spotted Star Flounder (201604100).
Verasper variega-tus belongs to the flounder family, flounder family, star flounder genus, commonly known as spotted treasure, leopard, lace claw, distributed in the Yellow and Bohai Seas. Round spotted flounder is a cold and warm large benthic fish, the body is oval, the body shape is beautiful, colorful and beautiful, is the traditional precious fish species in northern China, the folk proverb "spring flower autumn fish" of the "flower" is the spotted treasure (round spotted star flounder). Round spotted flounder is larger, fast growth rate, tender and delicious flesh, rich in a variety of vitamins and trace elements, in addition to the round spotted flounder strong adaptability, disease resistance and stress resistance is strong, can carry out factory breeding, excellent breeding traits, breeding prospects.
Tianjin Bohai Fisheries Research Institute in Tianjin area to introduce round spotted flounder for factory breeding, after more than 1 year of breeding, have reached the specifications of commercial fish, aquaculture economic benefits are very impressive, so summarized suitable for Tianjin area of round spot flounder factory breeding technology, for the reference of farmers.
1. Factory breeding facilities
Farms are selected in areas with sufficient water, no pollution and good water quality. Can be used in factory flow-water aquaculture and circulating water aquaculture, breeding pond for round or square cement pond, can use the original breeding semi-slippery tongue fish, turbot and other factory culture cement ponds, the area is generally 30 meters
2, the depth of the pool is 1 meter, set 2 inlet pipes, the bottom of the pool
The surrounding area is inclined to the center at a slope of 4%, and drainage holes and drainage pipes are set up, and drainage risers are provided so that the pool water can be recycled.
Second, the selection and transportation of seedlings
Generally, fish species with a total length of more than 5 cm are selected for breeding, requiring complete body shape, normal color, complete scales, healthy and harmless, disease-free, uniform size, strong mobility, and good feeding. Fish fingerlings should stop eating for more than 1 day and cool down before transportation, it is best to carry out medicinal baths before stocking, and water temperature, dissolved oxygen amount, pH, nutritional salt and other factors should be considered when stocking. The transport of seedlings can be transported to aquaculture enterprises by means of plastic bag oxygenation transportation and living water truck transportation.
3. Aquaculture management
1. Water quality management The suitable water temperature for the cultivation of round-spotted star flounder is 10 ~ 20 °C, the general salinity is controlled at 20 ~ 30, the water depth is 50 ~ 60 cm, the pH is controlled at 7.5 ~ 8.5, the dissolved oxygen should be maintained at more than 5 mg / l, and the ammonia nitrogen content is not more than 0.02 mg / l. The flounder has a certain weakening of light, and likes to be under the soft light when gathering in groups, and the daily light can be 500 to 1000 lux. The water quality requirements are clear and transparent, when the water body is turbid, the fish swim restlessly, the amount of feeding is significantly reduced or even not fed, factory aquaculture is mainly in the form of flowing water for water, changing water 2 times a day, changing water 2 to 3 per day, and changing the amount of water per day in the summer high temperature is 4 to 5 flows.
2. Density control The culture density of the round-spotted flounder is generally controlled in the fish body tile area accounting for 70% to 80% of the pond bottom area. With the growth of the fish body, the fish body area gradually increases, and then exceeds the load capacity of the pool, and the difference in the growth of the fish body causes the individual size difference is obvious, the need for specification screening, sub-pond, the similar size of the fish body together aquaculture, in general, 1 to 2 months can be carried out once the specification screening, the fish grow to 25 cm long, the specification screening is not important, the need to divide the sparse density of the pool in time. The reference density of culture in production is shown in Table 1.
Table 1 Flounder culture density
3. Bait and feeding Factory aquaculture production is mainly based on feeding hard pellet feed and chilled small miscellaneous fish. Frozen anchovies, jade tendon fish, etc. can be used as chilled bait, chilled bait needs to be thawed, cleaned, selected and sorted before feeding, and regularly put the medicinal bait into the mouth of the chilled bait and then fed to achieve the purpose of disease prevention. Hard pellet feed and different varieties of chilled bait can be combined or fed alternately. The amount and frequency of feeding need to be flexibly controlled according to the feeding status of the fish, the water quality and the size of the fish. Fry under 10 cm are fed 2 to 3 times a day, the daily feeding amount of hard particles is 2% to 3% of the fish body weight, the daily feeding amount of chilled bait is 6% to 7% of the fish body weight, the fry above 10 cm is fed 1 to 2 times a day, the daily feeding amount of hard particles is 1% to 2% of the fish body weight, and the daily feeding amount of chilled bait is 4% to 6% of the fish body weight. When the water temperature is below 10 °C and above 24 °C, the fish feed intake decreases, and the number of baits and feeding should be reduced or the feeding should be stopped.
4. Body color adjustment In the process of factory breeding of round spotted flounder in Tianjin, the body color of round spotted flounder is darker and darker. Body color adjustment and solution measures: adjust the light intensity during the breeding process, control at 700 ~ 1000 lux; strengthen feed nutrition, use high-quality compound feed supplemented with chilled small trash fish, adjust feed nutritional needs; timely screening of sub-ponds during the breeding process, appropriately reduce the density of aquaculture.
5. Disease prevention and control The breeding of Tianjin round spotted star flounder is currently in its infancy, and has not yet formed a large-scale aquaculture production, the survival rate of aquaculture is high, and no serious diseases have been found. For the prevention and treatment of diseases in the process of breeding, prevention should be the mainstay.
(1) Maintain a good water quality environment: change the water regularly every day, remove the bait, feces and other dirt at the bottom of the pond in time every day, ensure that the aquaculture water quality is fresh, the bottom of the pond is clean, and the dissolved oxygen is sufficient.
(2) Control the quantity and quality of feeding bait: the amount of bait feeding should be moderate, the feeding of the bait should be comprehensive, the particle size should be moderate, in order to facilitate digestion and absorption, the chilled bait should be strictly cleaned and disinfected, and the spoiled bait should not be fed.
(3) Maintain a suitable breeding density: in the breeding process, it is necessary to divide the pond in a timely manner, reduce the breeding density, and carry out specification screening at the same time as the pond to avoid the occurrence of uneven feeding.
(4) Disease prevention: The breeding workshop should be equipped with special tools and strictly disinfected before use. Workers entering and leaving the breeding workshop should disinfect the tools used and equipment such as water boots. In the process of breeding, it is necessary to regularly mix medicine bait for disease prevention, strictly prohibit the use of banned fish drugs, find out the pathogen of the disease, prescribe the right medicine, and treat it according to the course of treatment until it is cured. And timely eliminate seriously diseased fish to prevent the spread of disease.
IV. Summary and Discussion
A total of 73,000 seedlings of round-spotted star flounder were introduced in Tianjin, and the total area of factory demonstration was 4,900 meters
2, cumulative sales of round spotted stars
[Jishan Huayao toutiao number] flounder commercial fish 51492 kg, the sales price of 45 yuan / kg, the economic net income of 996,000 yuan. From the current breeding situation, the growth rate of the round spotted star flounder is fast, 5 cm of round spotted star flounder seed after 12 months of artificial breeding, the average weight can reach more than 500 g / tail, to meet the commercial fish sales specifications, the variety of factory breeding requires water temperature control at 10 ~ 20 °C, salinity control at 20 ~ 30, suitable for factory culture in Tianjin area. After the breeding test, the water quality regulation, breeding density, bait feeding, body color adjustment, disease prevention and other breeding technology points of the factory culture of the round spotted star flounder have been preliminarily summarized, and large-scale promotion and demonstration can be carried out.
