The Latest Achievements of Soilless Ecological Culture of Loach in Still Water

Misgurnus anguillicaudatus soilless fish and vegetable symbiosis project is suitable for returning home to start a business, diversified economy and development migration in the reservoir area. Mr. Zhou Wenzong, inventor of the project, associate researcher of the Institute of Biotechnology of Nanjing University, director of the Ecological Environment Research Center of Henan Academy of Sciences, and double doctor of ecological engineering and aquatic biology in the field of ecological aquaculture in China, has presided over 24 provincial projects, participated in the Tenth five-year Plan, the National Science and Technology Program, the 863 Program and 11 provincial projects, and holds 7 national invention patents as the first inventor. After years of scientific research and tackling key problems, following the invention of the soilless ecological culture model of Monopterus Albus and the realization of shallow water soilless semi-artificial propagation of Monopterus Albus, it has broken through the traditional culture methods in recent years. to create four major scientific and technological innovation projects: "soilless culture of Loach in impervious film pond", "soil culture of Loach in cement pond", "cultivation of Loach with biogas slurry" and "symbiosis of Loach with aquatic vegetables in the same pond". 1. The present situation and development trend of Loach culture Misgurnus anguillicaudatus is distributed in rivers, ditches, paddy fields, ponds, lakes and reservoirs all over China, especially in the middle and lower reaches of the Yangtze River and Pearl River basins. Misgurnus anguillicaudatus, which enjoys the reputation of "turtledove in the sky, Loach underground" and "ginseng in the water", is not only a nutritious and popular delicacy, but also has high medicinal value. However, at present, the market supply in our country is only 50 ~ 60,000 tons, and the gap is large. The market situation that supply falls short of demand drives the price of Loach to rise year after year. From 1995 to now, the price of Loach has risen from 5 yuan / kg to 20 yuan / kg, and the sales price of Misgurnus anguillicaudatus in winter is as high as 50 yuan / kg in Jiangsu, Zhejiang and Sichuan markets. The larger market space and profit space make the Loach culture industry develop rapidly. The cultivation area of Misgurnus anguillicaudatus in China is 15 million ~ 20 million fish (20 ~ 30 million mu), and 15 million ~ 20 million kilograms of seedlings are needed every year. The market sales of about 500 million yuan are mainly concentrated in Jiangsu, Henan, Hubei, Shandong, Anhui and Sichuan provinces. The breeding species is basically Paramisgurnus anguillicaudatus (Loach). With the rapid development of Misgurnus anguillicaudatus artificial breeding industry, the contradiction of weak breeding technology has gradually emerged. At present, the main factors restricting its development include: 1. The limited source of seedlings is the basis of production. At present, the seedlings are mainly wild fishing. The proportion of artificial breeding seedlings is very small, and large-scale artificial seedling breeding enterprises have not been seen in China. The large-scale breeding farms in Anhui, Sichuan, Hubei and other places are mainly waterspray cultivation. The main reason is that the survival rate of Loach seedlings with body length 7~20mm (in the transition period from Gill respiration to intestinal respiration) is very low, with an average of less than 20%, which seriously restricts the large-scale production of fish fry. The rising market price of Misgurnus anguillicaudatus is bound to cause a shortage of wild Loach seedlings, form a vicious circle, and increase the cost of raising Loach. 2. The conversion efficiency of formula feed is low. At present, the research on the nutritional requirements of Loach is not deep enough. There are few special formula feed for Loach in China, and most of them sell other fish feed formula as Loach formula with little or no change. Therefore, the feed utilization rate is very low, and the feed coefficient is generally between 4.0 and 6.0, and some even as high as 10.0. It seriously restricts the healthy development of Misgurnus anguillicaudatus breeding. 3. Single culture mode domestic Misgurnus anguillicaudatus culture is concentrated in Jiangsu, Henan, Hubei, Anhui and other provinces, which is basically pond purse seine culture mode, and most of the species are Loach. There are no successful cases in cage culture, soilless culture and Loach culture. 4. The degree of intensive culture is not high because the artificial culture of Loach is still in its infancy, mainly sporadic single-household and single-pond hoarding mode, so there is a low level of culture, mainly empirical culture, many new culture techniques can not be effectively popularized, diseases and insect pests can not be effectively controlled, factory culture and four seasons culture are still rare. 5. Serious water pollution due to the high density of Misgurnus anguillicaudatus culture, large food intake, large amount of residual bait and excretion, easy eutrophication of culture water, poor oxygen in lower water body, increase of sulfides, organic matter and nutrients in surface water, accumulation of residual drugs, harmful microorganisms and phagocytic organisms are dominant, ecological imbalance in culture waters, all kinds of diseases occur frequently, especially in the middle and later stages of culture. It has brought serious pollution to the groundwater and the surrounding water.

2. The development trend of Misgurnus anguillicaudatus culture with the development of science and technology and the expansion of culture scale, Misgurnus anguillicaudatus culture will show the following development trend: 1. The culture pond tends to be miniaturized and intensive (about 400 to 500 kilos is better). Smaller feeding space is beneficial to Loach feeding, physical energy consumption is smaller, water quality is easy to control, thus increasing the yield per unit area. 2, soilless culture, factory culture or circulating water culture is the development direction. The Loach of soilless culture has no fishy smell, good quality, easy to control water quality, fast growth rate and high survival rate; Loach has strong vitality, tolerance to hypoxia and requires shallow water environment, which is very suitable for factory culture or circulating water culture. 3, the prospect of cage culture is good. China is rich in ponds, pits and other small water bodies, cage culture of Loach is easy to manage, convenient fishing, high yield, good development prospects. 4, improve the Loach symbiosis system. Misgurnus anguillicaudatus likes dark light, can eat insects, has strong activity, has a high degree of eutrophication and high content of ammonia nitrogen, is suitable for planting aquatic vegetables on the water surface, can purify water quality, reduce the harm of diseases and insect pests, promote the growth of Misgurnus anguillicaudatus, and improve economic benefits. It is a very good symbiotic system of fish and vegetables. 5. Cross breeding and homozygous breeding are the key points of Misgurnus anguillicaudatus seedlings. At present, the main factor restricting the benefit of Misgurnus anguillicaudatus culture is the slow growth rate of Misgurnus anguillicaudatus, which is difficult to reach 3 times per year, mainly due to the slow growth rate of male Loach. The growth rate of female Misgurnus anguillicaudatus is 80% and 100% faster than that of male, so feminized breeding will become the focus of research. Misgurnus anguillicaudatus has the advantages of fast growth, strong stress resistance and more tolerance to hypoxia, but the meat is loose and the taste is not as good as that of Misgurnus anguillicaudatus, which is not resistant to long-distance transportation, slow growth speed and easy to occur, so it is an inevitable trend to cross breeding as parents. 6. Deep processing needs to be strengthened. Misgurnus anguillicaudatus has great potential for deep processing and has an extremely broad market in the fields of health care, beauty, food and medicine, which is helpful to prolong the shelf time on the market and improve the added value. The patents and proprietary technologies of "soilless culture of Loach in impervious film pond", "soil culture of Loach in cement pond", "culture of Loach with biogas liquid" and "symbiosis of Loach with aquatic vegetables and fruits in the same pond" created by Dr. Zhou Wenzong, it is precisely to meet the above development trends and to tackle key scientific research and achieve industrial production.