Northern winter factory breeding workshop redfin oriental puffer set three-wart pike crab technology
Text / Wang Guangyu
Redfin Oriental Pufferfish (Takifugu rubripes), commonly known as pufferfish, Wax head, etc., is a warm water fish, is currently one of the leading excellent fish species in China's marine aquaculture fish. Its economic value ranks first among the pufferfish, and it is one of the important export foreign exchange earning economic fish. With the limited liberalization of the domestic market, the scale and industrialization of redfin oriental pufferfish culture in the northern region have been continuously improved. Redfin Oriental Pufferfish culture takes 2 years to reach the commercial specifications, because it can not adapt to the low temperature environment, the northern region of the 1-year-old fish overwintering has become an important part of production, and directly affect the success or failure of the entire breeding process.
Portunus trituberculatus , commonly known as pike crab , sea crab , etc. is a warm water crab, widely distributed along the coast of China, and is a large-scale marine crab with high economic value. Due to the strong seasonality of the cultivation and fishing of three-wart pike crab, it is concentrated on the market every autumn and has low economic benefits. At the same time, the early harvest of three-warty pike crabs is in the hulling growth stage, with a large proportion of low fertilizer fullness and low commodity value. Therefore, collecting three-wart pike crabs with low fertilizer fullness in autumn is a good way to improve quality and efficiency.
The single culture technology of redfin oriental puffer crab and three-wart pike crab is relatively mature, in order to achieve higher economic benefits and resource conservation and comprehensive utilization, since 2017, Caofeidian District of Tangshan City, Hebei Province, has carried out winter factory breeding workshop redfin oriental puffer crab three wart pike crab test, by the end of 2019, after three years of testing and improvement, a mature winter factory breeding workshop redfin oriental puffer and three wart pike crab set breeding mode has been formed. This model, while completing the wintering of the factory breeding workshop of the 1-year-old redfin oriental pufferfish, implements the three-wart pike crab set culture, improves its fertilizer fullness and chooses the opportunity to go to market, achieving the goal of "improving quality and efficiency, green development", with significant economic benefits and innovating a new model of efficient utilization of resources.
First, the factory workshop conditions and preparation
(1) Factory workshop conditions
The workshop should have good temperature retention and heat insulation power, and the roof of the room should be left with a lighting belt, and the intensity of daylight illumination should be controlled at 500lx~1000lx. The aquaculture pond is square or rectangular, the four corners are rounded and curved, and the surface is coated with special paint for aquatic products; the bottom of the pond is equipped with a drainage hole, with a diameter of 110mm to 160mm, and the pool edge is inclined to the drainage hole with a slope of 5% to 7% ; the single pond area is 35m2 and the pool depth is 1.6m.
(2) Water quality indicators
The water temperature is controlled at 17 °C to 18 °C, the daily change is ≤ 2 °C, the salinity is controlled at 24 to 30; the pH value is 7.8 to 8.3; the dissolved oxygen ≥5 mg/L; the ammonia nitrogen ≤ is 0.4 mg/L; and the aquaculture water is sand filter seawater.
(3) Facilities and equipment
1. Water supply and drainage system
Including reservoirs, sand filter tanks, distribution tanks, pumps and inlet and drainage pipes, tailwater purification treatment tanks, etc. The reservoir is an outdoor pond with a silt thickness of ≤ 10 cm and a depth of ≥ 2.0 m. The sand filter tank is equipped with at least 2 or more, and the water filtration capacity of each sand filter tank is ≥ 100m 3/h, and has an automatic backwash function. The distribution tank has the functions of regulating the temperature and adjusting the salinity.
2. Inflatable facilities
Including blowers, inflatable pipes, sub-control valves, gas dissipation stones, etc., the wind pressure and air volume of the blower are matched with the total water body and water depth of the workshop aquaculture, and the inflation requirements can ensure that the dissolved oxygen ≥ the workshop pool water is 5mg/L.
3. Other facilities
Temperature control facilities include geothermal wells, freshwater wells, heat exchangers and heating pipes, valves, etc. Power supply facilities include transformers, distribution rooms, generator sets, etc. At the same time, it is equipped with laboratories, fishing medicine warehouses, small cold storage, etc., with a cold storage capacity of 10t to 30t and a storage temperature of ≤-16 °C.
(4) Disinfection of immersion ponds
The factory workshop breeding pond needs to be soaked with fresh water before use, and the soaking time is 2d to 3d. After soaking, the breeding pond is sprinkled with 20ppm of formaldehyde solution, leaving 20cm of water at the bottom of the pool, soaking time greater than 30min, and then brushed and then set aside.
Second, key technologies
(1) Three-wart pike crab is stocked in the factory workshop
1. Stocking time
Every year after the National Day, the fresh three-wart pike crab is purchased and put into the factory workshop breeding pond.
2. Specification standards
Each ≥ 200g, which requires normal body color, smooth body surface, complete appendages, strong individuals, strong vitality, and no disease. It is best to choose a three-wart pike crab with a certain degree of fertility to improve the survival rate of the set.
3. Stocking density
Stocking density 35kg/pond, unit area of 4 animals/m2 ~5/m2.
4. Enter the pool for disinfection
Before entering the pool, the three-wart pike crab is bathed in a 20ppm formaldehyde solution for 30 min.
(2) Redfin Oriental Pufferfish is stocked in the factory workshop
1. Stocking time
From the end of October to the beginning of November every year, when the water temperature of the pond drops to 14 °C to 15 °C, the pond is pulled out of the pond by means of a dragnet, and the fish with diseases, deformities and thin bodies are removed after leaving the pond, and then enter the factory workshop breeding pond to reduce the occurrence of diseases during the wintering period and improve the survival rate of wintering.
Each ≥ 250g of 1-year-old redfin oriental pufferfish, which requires normal body color, smooth body surface, no disease and no injury, and strong vitality.
Stocking density of 800 fish /pond ~ 1000 fish / pond, unit area of 16 fish / m 3 ~ 20 fish / m 3.
Freshwater oxygenation bath or 20ppm formaldehyde solution immersion bath can be used for disinfection, and the time is controlled at 30min to 40min.
(3) Water quality regulation
The water depth of the workshop pond is controlled within 1.5m, the total water volume of each breeding pond is ≥50m3, the water temperature is controlled by about 17 °C to 18 °C, and the daily change ≤ 2 °C. Monitor the water temperature daily, monitor salinity, ammonia nitrogen and other indicators every week, monitor heavy metals, microorganisms, vibrio, etc. every month or irregularly, and deal with problems in a timely manner. Every 3d water change, each water change is 100%, the water change temperature difference is ≤ 2 °C, the salinity is controlled at 24 to 30, the salinity change is ≤3, to avoid violent fluctuations, the rational use of microecological preparations in the breeding process, and regularly sprinkle beneficial microecological preparations such as bacillus, EM bacteria, and nitrifying bacteria in the distribution pool.
Third, the main points of management
(1) Bait selection and feeding
1. Type and quality of bait
According to the stock of redfin oriental pufferfish, the bait is carried out, mainly chilled small miscellaneous fish, which requires freshness and no spoilage. Three-wart pike crabs feed on deposited bait, excrement, etc., and do not bait alone.
2. The amount of bait thrown
According to the size of the redfin oriental pufferfish, small trash fish with good palatability are selected, and the daily bait rate is 4% to 5% of the total weight of the fish in the breeding pond.
3. Bait handling
The frozen bait is first thawed at low temperatures, then rinsed with fresh water and fed.
4. Throw bait
Bait is given once a day before dawn. Observe the activities and feeding conditions of fish and crabs when feeding, and adjust the amount of bait in time according to the feeding situation.
(2) Clear the pond
Clear the pool once every 3d, before changing the water. When clearing the pond, the fish and crabs are kept in the pond, first of all, the water level of the breeding pond is reduced to 40cm to 60cm, the residue in the pond is removed, the pool wall and the bottom of the pool are brushed, and after brushing, it can be replaced with new water. In the process of nesting, no ponds are divided or inverted.
(3) Disease prevention and control
The disease is mainly prevention, maintaining the stability of water quality indicators, improving the immunity and resistance of the redfin oriental pufferfish and the three-wart pike crab, and doing a good job in disinfection at all stages. Select the water in the sea area with good water quality and high tide to ensure the water level of the reservoir; the quality of fresh or frozen bait should be guaranteed, and the bait of poor quality should not be fed; beneficial bacteria are used in the breeding process to inhibit the growth of harmful bacteria; breeding utensils are strictly disinfected to reduce the chance of cross-infection; each morning and evening patrols the pond once a day, make a good record of breeding production, and take appropriate measures when the disease is found. In particular, it is necessary to pay attention to the export product of the redfin oriental pufferfish to comply with the provisions of japan's "affirmative list system" on the use of puffer fish.
(4) Harvest time
According to the market situation, the three-wart pike crab began to be sold before New Year's Day until after the Spring Festival. From mid-April to the end of the month, the 1-year-old redfin oriental pufferfish will start selling or growing in ponds after wintering.
Fourth, economic benefit analysis
According to the above nesting mode, from 2017 to 2019, a total of 40320.00m2 was implemented in Caofeidian District of Tangshan City. The specific nesting results are detailed in Table 1.
Table 1 Results of three-wart pike crab culture in the redfin oriental puffer in the factory breeding workshop
The mortality rate of the factory wintering monoculture mode of redfin oriental pufferfish is generally about 7%, the mortality rate of this nesting mode is 2.2%, and the weight gain rate is ≥ 60%. The mortality rate of single breeding in the factory workshop of three-wart pike crab is generally 7% to 20%, the mortality rate of the nesting mode is 5.5%, and the weight gain rate is ≥ 15%, of which in the early stage of nesting, the death of three-wart pike crab in the process of adapting to the breeding environment is relatively large.
By April 2020, the 1-year-old redfin oriental pufferfish will be sold or raised in ponds, and the specific economic benefits of this set of culture models are detailed in Table 2.
Table 2 Economic benefits of redfin oriental puffer crab culture in factory breeding workshop
After three years of implementing this set of breeding models, the comprehensive breeding cost is 20.045 million yuan, the total sales volume is 41.5814 million yuan, the net profit is 13.6498 million yuan, the annual profit is 4.5499 million yuan, and the unit water body benefit reaches 338.54 yuan, and the economic benefits are remarkable.
5. Summary
The redfin oriental pufferfish and three-wart pike crab nesting mode makes full use of the aquaculture water body, one water breeds two things, and the two harm each other is limited, and there are suitable water quality conditions for both in the breeding process. Compared with the single breeding mode of redfin oriental puffer crab and three-wart pike crab, this model has achieved quality and efficiency increase for the breeding of three-wart pike crab, three-wart pike crab does not bait alone, improves the utilization rate of bait, saves the cost of nesting, after continuing to fatten, the quality of three-wart pike crab is improved, the yield is increased, and according to market conditions, the time to market is controlled and the profit margin is increased.
At the same time, this mode plays a role in purifying water quality, the frequency of water exchange in the nesting process is reduced, the amount of water exchange is reduced, the sedimentary bait and the excrement of the redfin oriental pufferfish are significantly reduced, the water quality of the breeding pond is better, the mortality rate of the 1-year-old redfin oriental pufferfish is reduced, and the quality of the tailwater discharge of the breeding tailwater is improved. This set of culture mode maximizes the benefits of breeding, and achieves the purpose of saving and utilizing resources, improving quality and efficiency.
Through three years of research and experimentation, demonstration and promotion, in the northern winter, the use of factory breeding workshop to carry out the redfin oriental puffer and three wart pike crab set culture, with simple operation, small breeding risk, obvious water purification effect, significant economic benefits and other characteristics, has a good promotion and application value, expanded the development space of the two breeding species of redfin oriental pufferfish and three warts pike crab.