What are the four innovative core technologies of the ecological circular farming of rice field eels and loaches?

The rice field eel static-water soilless farming aquaponics project is suitable for returning-home entrepreneurship and diversified operations. The project inventor, Mr. Zhou Wenzong, associate researcher at the Institute of Biotechnology of Nanjing University, director of the Ecological and Environmental Research Center of the Henan Academy of Sciences, and holder of dual doctorates in ecological engineering and aquatic biology in China's ecological farming field, has presided over the completion of 24 provincial-level research projects, participated in 11 projects including the "Tenth Five-Year Plan" National Major Science and Technology Special Project, the National Science and Technology Tackling Plan, the 863 Program, and provincial-level projects, and holds 7 national invention patents as the first inventor. After years of scientific research, he achieved the "Ten Major Technological Innovations," and in recent years he has broken through traditional farming methods to pioneer four major technological innovation core technologies: "rice field eel static-water soilless farming in anti-seepage membrane ponds," "loach static-water soilless farming in anti-seepage membrane ponds," "overwintering of cage-cultured eels and early stocking," and "aquaponics in rice field eel and loach farming ponds":
Core Technology One: Patented technology for rice field eel static-water soilless farming in anti-seepage membrane ponds
The film-pond eel farming technology is the third-generation invention technology by Dr. Zhou Wenzong, following cage eel farming and cement-pond eel farming. It can also realize the dream of farming rice field eels in water-scarce northern regions, and can likewise be used on abandoned land such as saline-alkali land. On December 2, 2009, CCTV-7's Science and Technology Garden program reported this technological innovation achievement under the title "Clever Use of Film to Farm Rice Field Eels." Compared with traditional cage and cement-pond eel farming methods, the anti-seepage film earthen-pond eel farming method has the following characteristics:
Building a greenhouse over the film pond solves the problems of cage farming being unable to overwinter and large water surfaces being difficult to manage. At the same time, compared with building cement ponds, the pond construction cost is only half that of a cement pond; a single worker needs only one day to complete the digging of a film pond, installation of inlet and outlet ports, and laying of the film. The anti-seepage membrane uses high-quality polyethylene virgin resin made by Italian fully automatic geotechnical production equipment through three-layer co-extrusion technology, and is produced in accordance with the American GRI standard and ASTM testing standards. It is non-toxic, environmentally friendly, and quick to install. Notable characteristics: high mechanical strength, good chemical stability, resistance to plant root penetration, high anti-seepage coefficient, anti-aging, UV resistance, and strong anti-decomposition ability, which can guarantee an eight-year service life for the anti-seepage membrane. Film eel ponds are easy to observe, easy for feeding training, and convenient to manage; water changes and sludge clearing are thorough, and the water body has a long shelf life; spraying liquid medicine leaves no dead corners, and disease prevention and control results are good; winter water temperature is higher than in cement ponds, which helps extend the rice field eel feeding period; fishing operations require low labor intensity; the pond walls are very smooth and will not cause damage to the mucus membrane on the eel's body surface, which can prevent fish diseases; land reclamation is the best, suitable for development and utilization of collective construction land after land transfer; the anti-seepage membrane has good plasticity and reparability; eel ponds do not need dealkalization or disinfection.

Core Technology Two: Patented technology for loach static-water soilless farming in anti-seepage membrane ponds
Traditional loach farming uses open-air ponds with soil and free-range methods, with a per-mu yield of only two to three hundred kilograms, making it difficult to meet market demand. Moreover, because loaches have smooth, round bodies and a habit of burrowing into mud, harvesting is relatively difficult, resulting in a low recapture rate in loach farming, which directly affects the yield and economic benefits of farming. In contrast, our center's industrialized intensive static-water soilless loach farming, which organically combines film ponds and cages, extends the loach growth period so that production can be realized in all four seasons. It also has the characteristics of high stocking density, flexible selection of waters for cage placement, high per-unit yield, convenient management, easy harvesting, and convenient overwintering, making it an intensive farming method.

Core Technology Three: Patented technology for overwintering of cage-cultured eels and early stocking
The conventional stocking time for rice field eel farming is usually concentrated from late June to the end of July each year (stocking too early leads to unstable temperatures, and rice field eels are in their peak breeding period, resulting in a lower survival rate). The supply-shortage situation causes seed prices to soar (18-25 yuan/jin). However, if stocking occurs after August, the farming time is short and affects the growth rate of the rice field eels. In recent years, Zhou Wenzong broke with convention to successfully develop and implement early stocking technology at his demonstration base. Dr. Zhou Wenzong's successful practice of stocking "overwintered seedlings" and artificially bred seedlings proves that temperature difference and breeding season are not the key factors restricting early stocking. As long as eel seeds are correctly selected and seedling quality is improved, early stocking of rice field eels is entirely feasible. Using early stocking technology, stocking can be done in all four seasons (such as April, May, August, and September). Seedlings purchased in April and May cost only a little over ten yuan, and during the peak stocking period at the end of June they can sell for more than twenty. Why not strive for such a large profit margin? The use of early stocking technology relatively extends the rice field eel farming cycle and increases the weight-gain multiple. Moreover, combining overwintering with building a greenhouse over the film pond not only solves the overwintering problem but also increases economic income.

Core Technology Four: Patented "aquaponics" technology for rice field eel and loach farming ponds
The "aquaponics" patented technology is a major discovery by Dr. Zhou Wenzong in the field of ecological eel and loach farming. In pond-cultured rice field eels, water hyacinth and water peanut are generally grown on the water surface. Although they have the function of regulating water quality, they compete with the eels for space. In the "aquatic vegetables - microorganisms - rice field eels and loaches" aquaponics system established by Zhou Wenzong, aquatic vegetables can absorb nutrient salts such as nitrogen and phosphorus excreted from fish metabolism in the farming water, remove 80-90% of suspended substances and 70-80% of organic substances in the water, reduce biological oxygen demand by 90-95%, and can keep the pH value of the water within the standard range. Aquatic vegetables can also disinfect the water body (the plant bactericides secreted by their root systems can kill 90-95% of pathogenic bacteria), giving the fish pond water body self-repair capability. The complete compound feed configured in this aquaponics system contains high-quality raw materials such as fish meal and bone meal, which happens to supplement the supply of trace elements. The successfully grown vegetables are water spinach, water dropwort, lettuce, and tomato. This not only increases economic benefits but also avoids the environmental pollution caused by the rampant growth of water hyacinth.