Detailed Explanation of Key Technologies and Development Strategies for Industrialized Fish Farming

With the continuous advancement of urbanization and industrialization, land resources are constantly decreasing, water resources are increasingly scarce, and the deterioration of fish farming environments and water quality has drawn growing attention to the safety of edible fish. Developing water-saving, pollution-free industrialized fish farming technology is undoubtedly the direction for addressing the shortage of land and water resources and reducing environmental pollution.

Overview of Industrialized Fish Farming

The development of industrialized fish farming in China is very uneven, and there is an even greater gap compared with foreign countries. The overall situation is: the north surpasses the south, seawater surpasses freshwater, and new fish farming areas surpass old ones.

It is mainly distributed across four regions: first, some seawater aquaculture counties and cities on the Liaoning and Shandong peninsulas, such as Dalian, Yantai, Rongcheng and Weihai; second, the Northeast region, mainly in Heilongjiang Province; third, the Central Plains region, mainly in the Xuzhou-Huai'an area; fourth, the Hexi Corridor, mainly along the line from Lanzhou, Gansu to **Urumqi.

In the vast number of counties and cities across China, industrialized fish farming is still blank, and even in the above four regions, industrialized fish farming varies greatly in quality. In the economically developed Pearl River Delta, relatively successful industrialized fish farming is also not commonly seen.

Characteristics of Industrialized Fish Farming

1. High yield per unit area (water body): The yield of traditional pond fish farming is generally about 1000 kg per mu, and the annual yield of intensively farmed fish ponds equipped with aeration machinery is generally only about 2000 kg. If calculated at a water depth of 2 m per mu, the annual yield of traditional pond fish farming is only about 1.5 kg per cubic meter of water body. With industrialized fish farming, however, the annual yield per cubic meter can reach 10 kg, 20 kg, 50 kg or even higher.

2. Shortened production cycle, conducive to balanced market supply: Because modern equipment and management techniques are adopted, excellent water quality and ecological environment are provided, and high-protein, complete-nutrition feed is supplied, the farmed species eat their fill and grow quickly, suffer few or no diseases, and their growth cycle is noticeably shortened.

3. Lower feed conversion ratio: Because each subsystem of industrialized farming provides the best living conditions for the farmed animals, the feed conversion rate increases, the fish grow faster, and the feed conversion ratio naturally decreases.

4. Small footprint, low investment, easy management: Taking traditional pond fish farming with an annual output of 100 tonnes (200,000 jin) as an example, calculated at a yield of 1 tonne (2,000 jin) per mu, at least 100 mu of water surface is needed. To produce 100 tonnes (200,000 jin) of fish using industrialized farming, at 50 kg per sq m, only 4000 sq m of land is needed.

5. Low waste and wastewater discharge: Industrialized farming generally has waste and wastewater treatment and centralized recovery facilities, so the amount directly discharged into the environment and the degree of impact are both limited.

6. Little affected by external climate: Industrialized farming is mostly carried out indoors and is almost unaffected by weather, temperature and other external climate factors, allowing year-round production.

Key Technologies for Industrialized Fish Farming

1. Water treatment: The "water" in industrialized fish farming is key. In areas with abundant water sources, open-flow fish farming is allowed, in which water enters the fish pond and is discharged without being recycled, resulting in relatively high water consumption. In water-scarce areas, however, recirculating filtration fish farming is mostly used, in which the wastewater discharged from the pond is purified and treated before entering the pond again as a water source, making water treatment especially critical.

2. Fully nutritious compound feed: The feed for industrialized aquaculture must be comprehensive in nutrition, and the lack of trace elements in recirculating water bodies must be taken into account. Efficient pelleted feed should be used, with a feed conversion ratio generally around 1 to 1.2, to reduce water treatment problems caused by fish excretion. Fresh feed produced within two months should be used, and nutritional diseases caused by feed spoilage should be minimized; any spoiled feed must absolutely never be used in industrialized farming production.

3. Selection of farming species: Industrialized aquaculture is a high-investment farming model with relatively high investment risk. When selecting farming species, economic benefit should be the focus, and several aspects should be fully considered:

a. Choose valuable species with high market prices, so that high farming costs bring high benefits and yield a relatively high return on investment. Generally, the price of commercial fish should be no less than 10 to 12 yuan/jin; otherwise there is no profit margin.

b. Choose species that are more technically demanding among valuable farmed fish and cannot be farmed under ordinary conditions, so as to obtain higher added value.

c. Make use of controllable water quality conditions to farm broodstock of valuable species, adjust the breeding season, and carry out fry and fingerling production in off-season periods.

d. Carry out fry and fingerling-stage farming in winter, which can shorten the production cycle of commercial fish.

4. Disease prevention: Industrialized farming generally involves small water bodies and high density, so disease prevention is very important, and it must be ensured that no disease occurs; otherwise, total loss can easily result. The main measures are as follows:

a. Choose healthy fish with no history of disease to put into the farming pond.

b. Disinfect them before they enter the pond.

c. Strictly control the water treatment process and install disinfection and sterilization equipment in the treatment system.

d. During the farming process, pay attention to the stress pressure on fish caused by environmental changes, including various disturbances and fluctuations in water quality, changes in water temperature, and so on. High stress pressure will reduce the disease resistance of fish.

e. Pay attention to the scientific nature of feeding and avoid overfeeding of fish; overfeeding also increases the burden on fish and makes them prone to disease.

f. Use dedicated tools and disinfect them frequently.

Points to Note in Developing Industrialized Fish Farming

At present, China's research on industrialized aquaculture still lags far behind the world level, and the relevant theoretical and technical systems are still far from complete. Industrialized fish farming is an industry with high benefits, high technology, high investment and high risk. If enterprises are interested in developing it, they should act within their means, choose the farming species, farming facilities and development base accurately according to their own specific conditions, give play to local natural and technical advantages, and conduct scientific, rigorous and objective analysis and demonstration of the technical route adopted, production costs and benefits, operational risks and other aspects.

1. The initial investment in industrialized fish farming is relatively high, so the selection of species for developing industrialized fish farming and the preliminary research work are very important, and investment must be made cautiously.

2. Compared with traditional farming methods, industrialized fish farming is a new thing with relatively high technical content, so farming enterprises need a team with high education and high quality that understands both technology and operation. Otherwise, no matter how good the facilities and technology are, the result can only be failure.

3. Relevant units should carry out joint research. Industrialized fish farming involves disciplines such as environment, feed, breeding, diseases, aquaculture, engineering, and electromechanical automation, and is a comprehensive systematic project. Relying on enterprises to fight alone makes it difficult to bear operational risks and achieve the unity of social benefits and enterprise benefits. Therefore, the government and research institutions should strongly encourage and support enterprises in trying and developing industrialized aquaculture, and conduct joint research on relevant technical difficulties.