Experts talk about cold-water fish farming
Moderator: Technology creates wealth, science and technology change lives. Audience and friends Hello everybody, welcome to watch the science and technology park program. The breeding of cold-water fish in China has a history of 40 years. For many years, it has been cultivated with a single species of red snapper. At present, this breeding situation has not met the market's diversified demand for cold-water fish food. Therefore, the introduction of new varieties, enriching species, and raising aquaculture technology have become urgent issues for the development of cold-water fish farming. However, Huang Yanping from Yanqing Yudu Mountain Breeding Base in Beijing has come up with a new path for how to raise cold-water fish. In just two years, it has produced more than 20 million eggs each year, cultivated 2 million seedlings, and raised 100,000 kilograms of commercial fish. Reporter: This is a cold-water fish breeding base in Yanqing Yudushan Natural Scenic Area. The breeding base covers an area of ​​approximately 100 mu, and the amount of spring water flow is 0.5 cubic meters per second, and the water quality meets the national first-class standard. In the cold water fish breeding, seed hatching and adult fish feeding. We still go inside to see. Reporter: Huang Gong Hello! Today, it's time to see your fish. Huang Gong: Let's go and see it! Reporter: You here are cold water fish breeding bases, warm water fish breeding bases, and hot water breeding bases. Why do you want to distinguish between them? Huang Gong: It is mainly based on the requirements of fish for the living environment, especially the water temperature, that people are artificially divided into these three types, like our native fish like carp, grass carp, and squid, which have a wide range of suitable temperature, generally as Warm water fish to distinguish, and in recent years, into some tilapia, freshwater white Stork, rainbow quail that it adapt to the water temperature below 15 degrees, it will be ice to die, so it is classified to hot water fish However, the current fish in this field can't survive above 20 degrees, so called cold-water fish, let's make three divisions from the convenience of breeding. At present, with the raising of the level of culture, the demand for breeding of other cold-water fish species is increasing all over the country. There are mainly three types of cold-water fish species. The first is the adoption of bio-techniques and the introduction of quality rainbow trout varieties such as triploid. Rainbow trout, all-female rainbow trout, rainbow trout, hard head louse, golden trout and so on. The second is the introduction of foreign new cold water varieties: such as Atlantic salmon, silver bream, white peony, mountain nunnery and so on. The third is the development of China's indigenous cold-water fish species such as red snapper, small-scale fish, jerk fish and so on. Huang Gong: Like these cold-water fish that we have raised, it belongs to high-protein, high-fat. This kind of fat is unsaturated fatty acid. It has a softening effect on cardiovascular and belongs to health food. And this kind of fish requires The environment is very harsh. It is completely spring water and cannot have any pollution. Therefore, it is entirely possible to meet the requirements of raw food for healthy food. Nowadays, we have more varieties, such as newly introduced Atlantic salmon, silver carp, whitefish, and red carp. These are the treasures of carp. Atlantic salmon are native to the Atlantic Ocean and the Great Lakes region of the United States. And road closures population. The body is long and thin, with a white complexion, brown or green back, and black spots on the body side. After the success of artificial breeding, the development speed is very fast. In 2000, the total output accounted for more than 70% of the global trout aquaculture production. The silver carp was originally a migratory cold-water fish. Due to the continuous improvement of scientific and technological development and domestication methods, the silver carp can be intensively cultured in freshwater. The white-spotted pheasant is a member of the genus Pheasantidae. Its body is spindle-shaped, and its body color is gray-gray. It is named after white spots on both sides of the body surface. Under artificial cultivation conditions, the water level in the middle and lower layers of the flow pool is active. One of the main features of white spotted lice is the strong anti-infectiveness of the virus. Huang Gong: The red snapper belongs to the genus Euryptochea. This fish is mainly produced in the sea near the Arctic Circle. After artificial domestication, it can be bred in fresh water. It has a long-term physical appearance, and its color is very high. Gorgeous, especially if the wild male becomes sexually mature, it is very beautiful with dark red. 1. Just now we saw many new varieties of cold-water fish, some of which were introduced from abroad. Can these varieties adapt to our country in the future? Let's ask the researcher Shen Tingdong, a fishery expert of the Beijing Fisheries Research Laboratory. Moderator: Our scientific and technical personnel have done a lot of work in introduction, artificial breeding and so on. However, due to the relatively high environmental requirements for cold-water fish, can the average farmer raise cold-water fish? Shen Tingdong, an expert, must rely on technology to farm cold-water fish. If the fish is bred extensively according to tradition, the results will be counterproductive. Reporter: What difficulties have you encountered in keeping fish for so many years? Farmers: Also encountered. First, feed, I consider spending less money to buy a little bit of material, a little simple, I do not know why the fish grow too thin can not go up, the color does not look good meat is not very good. The second issue is hatching. We had previously hatched artificially. During the incubation period, the emergence rate was relatively low. I do not know what the problem was. The fish disease problem was another problem. Before we discovered the enteritis, some of the fish died and we were all anxious. Our analysis was that the prevention was not timely, and it was nearly dead. At that time, the price of fish was relatively high. Both of them were more than 20 yuan a pound, and 3.4 kilograms were dead. There are probably thousands of dollars, so in cold-water fish farming Must master technology and science. Reporter: From the point of view of this breeding process, to succeed, mastering science and technology is the key. What are the key technical points for breeding squid? Huang Gong: Like squid fish, its requirements for living conditions are relatively strict. In particular, the requirements for water quality are very strict. It requires no industrial and agricultural pollution, and some living pollution also has some impact on it. On the other hand, the temperature range that it adapts is from 5 degrees to 20 degrees. If it exceeds this range, it will be detrimental to its growth. Thirdly, it requires that the dissolved oxygen in the water is relatively high, generally about 1 liter per liter. Above 6 milligrams, cold-water fish adapt to a wide range of salinity, that is, they can live in fresh water and live in sea water. At present, from the perspective of breeding methods, cold-water fish have aquaculture and cage culture. In the Beijing area, mainly fish farming, after several years of exploration, they also concluded a set of artificial domestication, the high-density intensive fish farming technology. Reporter: What is high-density intensive farming? Huang Gong: High-density intensive farming means that in a limited body of water, it is possible to stock a relatively large number of species and produce relatively high yields. For example, in the past, we cultured some ordinary water-based, white-skinned catfish, which is filter-feeding, so the general amount, also reached 500,600 pounds, the high is also about 800 pounds, breeding some of the food , like squid after some micro-water treatment, or oxygenation measures, can reach 1500 pounds to 2000 pounds of such production, but like the squid such water conditions, its stocking capacity, is the first two kinds of fish 10 to 20 times, its output can also be said that an acre of land can produce more than 20,000 kilograms. Our cold-water fish are intensively cultured. Do you think it is feasible? Expert Shen Tingdong: Cold-water fish belongs to eating fish and is adaptable to high-density flow culture. A large amount of food fish can be cultured in limited water bodies, which is unmatched by other fish. The general stocking density of ponds is 800 to 1500 jin per acre, and high density water breeding is 20 to 30 stocks per square metre, with high density of water. The stocking density is tens of times higher than that of other ponds and the yield per mu is 5000 kilos. Therefore, the high density of water cultivating covers a small area, yields high per unit area, can fully utilize fish ponds and water, and increase production efficiency. ,reduce manufacturing cost. In particular, our country’s mountainous areas are rich in cold spring water resources and can use these resources to develop high-density cold-water fish farming. This will play a positive role in promoting mountainous areas farmers to shake off poverty and become rich and promote rural economic development in the mountains. Reporter: Huang Gong raises cold water fish, must create some necessary conditions for it, what are these necessary conditions. Huang Gong: Now generally speaking, due to the restrictions of the terrain, we generally use flowing cement tanks. The area of ​​this flow basin design must consider the amount of water. Generally 0.1 cubic meters per second, we can build an acre of water surface. To build a pool, we have to consider the following factors: fry, fingerlings, and adult fish. Because of its different size and size, the area and depth of the pond must be adapted. Take the concrete pool as an example, the juvenile pond area is 10-30 square meters. Water depth 20-50 cm. The adult fish pond area is 100-200 square meters and the water depth is 60-80 centimeters. The broodstock area is 150-300 square meters and the water depth is 70-90 centimeters. Huang Gong: Like the construction of a concrete tank, we think it is better to use a long pool, which is usually 2 to 4 meters wide. Its length is 4 to 6 times longer. In this case, there must be a certain slope of the bottom of the pool so as to facilitate the flow of water and sewage, creating a good environment for it. Reporter: Flowing fish farming, water from the top down will not cause pool water pollution. Huang Gong: In general, when the amount of water is relatively sufficient, most of us use the parallel form so that the water does not cross each other. Even if there is an outbreak, it will not be infected, but if practical, we must adopt parallel and The combined form of the tandem, generally arranged between the fry, try to adopt the form of parallel connection. In the adult pond, some tandems can be considered, but the length of the tandem should not exceed five ponds. If it is too long, the water quality deteriorates. Unfavorable growth. High-density stocking is the basis for high-density cultivation, which means that the fish fry must be stocked in sufficient quantities, and requires that the fish species have a strong body and neat specifications. The stocking size of general fish species is about 100-150 grams per tail. The amount of stocking should be determined according to the amount of water injected, the rate of water exchange, and the level of rearing. Usually, in the one year growing season, the stocking amount should reach 20%-30% of the annual production target. Feed is the key to high-density cultivation. Because the nutrients of fish under dense conditions are completely dependent on artificial compound feed, the quality of the feed is critical. The formulated feed for cold-water fish farming is usually based on high-quality fish meal, bean cake, and wheat flour as basic raw materials, adding a variety of vitamins, minerals, oil, etc. The feed particle size is divided into different grades from 0.3 mm to 8 mm, according to the size of the fish. And physiological conditions were selected. These feeds must meet the nutritional needs of cold-water fish during growth. When good feeds are used under good husbandry conditions, the feed efficiency can reach 100%, while the general compound feeds are mostly 60-80%. In order to achieve higher economic benefits, it is necessary to obtain maximum production volume in a limited area and amount of water. For this reason, it is necessary to always maintain the maximum stocking density and good feed efficiency in all the fish ponds. Careful feeding and management is the guarantee of high-density cultivation: Water temperature management and control are prerequisites for cold-water fish farming. Incubation water temperature is generally 7-13 degrees, the most suitable water temperature is 8-10 degrees. Juveniles are best kept in water with a slightly lower water temperature, preferably 10-12 degrees. Normally, the temperature of the rearing fingerlings is good at 10-15 degrees Celsius. The fish species raised in this water temperature environment are fast growing and have a high survival rate. The suitable water temperature for food fish breeding is 12-20 degrees, and the optimum water temperature for growing is 16-18 degrees. Dissolved oxygen in water should be more than 5 mg per liter, ammonia nitrogen should be controlled at less than 0.0075 mg per liter. The amount of water supply is an important factor in the success of dense culture. When the amount of water is sufficient, there is no need to increase oxygen and a considerable production amount can be obtained. In order to obtain the maximum possible throughput under a limited amount of water, it is necessary to increase oxygen. Under a certain amount of water, aeration can be increased by 3-5 times compared to non-oxygenated yields. Cold water fish in the water of less than 5 milligrams of dissolved oxygen per litre, it breathe faster, growth is slowed, therefore, usually 5 milligrams of dissolved oxygen per liter is used as an indicator of the management and control of dissolved oxygen in the tank. Huang Gong: Separate rearing of small and large specifications is an important measure to increase production volume. Cold water fish rearing for a period of time, the individual will have significant differences in growth, which is a common phenomenon in cold-water fish farming, so the large-size fish in a timely manner to filter out the pool, rather than one to raise the end. This is an important measure to strengthen aquaculture and increase yields. We see these cold-water fish are raised in the north, and cold-water fish as low-temperature fish, this fish can be cultured in the South? Experts: Due to the abundant conditions of China's vast aquaculture cold-water fish resources, not only northern areas can breed cold-water fish, but also in areas like Yunnan, Guizhou, Fujian, Guangdong, and Hainan in southern China, as long as they have cold spring water resources. In the aquaculture production process, it has low water temperature and adequate nutrition, and is equipped with high-protein nutrient feed, but also pay attention to the prevention and treatment of diseases, etc., can carry out cold-water fish breeding, but also need special attention in the southern region Breeding cold-water fish should pay attention to changes in summer water temperature. In hot summer, the water temperature is preferably kept below 18 long, and the temperature can't exceed 20. If the water temperature is too high, metabolic disorders will affect the growth and even death of fish. It will bring losses to fishermen. In short, not only the northern region can breed cold-water fish, but also in the southern region of China, cold-water fish farming can also be carried out. Experts suggest that the following steps should be taken into account during the aquaculture production process: 1 The selection of cultured species requires the first expansion of breeding species. Since the market changes rapidly, the original cold-water fish is mainly red snapper. With the market changing, it needs to be different. Varieties of cold-water fish species, so to expand the breeding species. To meet the needs of the market. 2 Pay attention to the quality of the seedlings, and choose a healthy, well-defined seedling as the selected species. 3, breeding methods: to adopt a single breeding method, these cold water fish culture species are food-eating fish, similar to the basic food, is based on artificial compound feed for breeding, therefore, these fish are not suitable for polyculture 4, feed: We breed cold-water fish, and we need to provide more comprehensive and high-energy feeds. Because the feed contains more oil, it is easy to oxidize. Pay attention to the feed shelf life is generally three months, if you want someone to buy some cold-water fish Species, you can go to Yanqing Yudushan cold water fish breeding base to buy. Moderator: At present, the cold-water fish breeding has gradually begun in the country. We believe that as long as we master scientific technology, it is not difficult to raise cold-water fish.