Pengze aquaculture farm, Jiujiang City, Jiangxi Province

Aquaculture farms

This data is reviewed by the project of data compilation and application of Science Encyclopedia of science popularization in China.

Aquaculture farm is a place where people propagate, cultivate and harvest aquatic animals and plants. Aquaculture generally includes the whole process of developing aquatic products from seedlings under artificial breeding management. In a broad sense, it can also include the proliferation of aquatic resources.

summary

Since the 1970s, the output of aquaculture in the world has increased rapidly, and its proportion in aquaculture is also increasing. The history of freshwater aquaculture in China can be traced back to the 11th century BC. In the 5th century BC, the book of fish culture was published. There are two main types of freshwater aquaculture: one is intensive culture of Cyprinidae fish in ponds to achieve high yield by feeding and fertilizing, and polyculture of fish with different feeding habits to give full play to water productivity. The other type is to raise seedlings in large and medium-sized waters such as lakes, reservoirs, rivers and paddy fields, mainly relying on natural bait to obtain aquatic products. In 1986, the area of freshwater aquaculture in China was about 46 million mu (about 61% of the total area), of which ponds accounted for 35%, concentrated in the middle and lower reaches of the Yangtze River and the Pearl River Delta; lakes accounted for 17%, mainly in the middle and lower reaches of the Yangtze River and northeast and Inner Mongolia; reservoirs accounted for 37%, distributed throughout the country; rivers accounted for 9%, mainly in Jiangsu and Zhejiang water network areas. The total output of freshwater aquaculture has been ranked first in the world for many years, increasing by about 22%. In 1986, the output was 2.95 million tons, accounting for 36% of the total output of aquaculture in China. Among them, 74% are ponds, 8% are reservoirs, and the rest are lakes, ditches and paddy fields.

type

It is very important to choose a good breeding site to improve the yield and quality of pearl. According to the type of water area, the aquaculture sites used in various places can be divided into the following types: (1) ponds: the area can be large or small, from several Mu to tens of mu, the water depth is 1.5-2.5 m, the water quality is fertile, and it is better to have irrigation and drainage facilities for easy management. (2) River Branch: also known as "River", because it is connected with the river, the water is in a flowing state due to the influence of tidal range, so it has sufficient dissolved oxygen, fresh water quality and rich food. If the water level difference is less than 35 cm and the flow rate is less than 6 m / min, it is the best breeding place. (3) waidang: refers to rivers, lakes and other waters, with wide water depth, large flow, high dissolved oxygen and good water quality. However, due to the complex environmental conditions, different types of nutrients can be formed, so we should pay attention to the selection of fertile and stable water quality, in order to facilitate the growth of mussels. (4) reservoirs: there are huge, large, medium and small reservoirs. Generally speaking, medium-sized reservoirs are not suitable for use because of their complicated sediment, deep water, large discharge and low primary productivity. However, with the increase of reservoir age, organic matter precipitation increases, and the water quality can gradually improve, especially in the reservoir area and small reservoirs close to rural residential areas and farming areas.

Breeding environment

1. Raise the water level of the pond. In view of the low water level of pond culture and the poor water source of the outer river, the method of gradually adding a small amount of pond water every three to five times was adopted to gradually raise the pond water level to more than 1.2 meters. Each time the water was added, it was selected from 10:00 a.m. to 2:00 p.m. in fine weather. 2. Increase dissolved oxygen in water. If there is oxygenation equipment, the aerator can be started for more than 2 hours at noon on sunny days. In case of rainy days or sudden weather changes, the aerator should be started in time. If there is no aerator, the submersible pump can be used to pump circulating water in the pool (before 3 pm, never in the evening), so as to enhance the convection and exchange of water. Biological control of water quality. All kinds of breeding varieties have entered the golden age of growth, but their excreta also increased significantly while their feeding was vigorous, which accelerated the deterioration of water quality. For this reason, it is suggested to choose the biological preparation made from a variety of microbial strains to control the water quality. The specific usage, dosage and precautions should be used correctly according to the instructions. 4. For the crabs in the outer river network, water grass should be put in to shade, reduce the direct sunlight and reduce the water temperature. In case of anoxia, the hanging boat propeller can be used to push water to increase oxygen and increase water flow.

Disease prevention

1. Using chlorine dioxide, dibromohydrin, bleaching powder or quicklime and other drugs to disinfect the water regularly to prevent the occurrence of diseases. 2. Appropriate amount of VC, immune polysaccharide or oral medicine can be added in the feed at intervals to enhance the disease resistance of breeding objects. 3. If the disease is found, it should be diagnosed and treated in time, and it should not be rushed to the doctor. When using drugs, we must follow the guidance of aquatic technical personnel, select high-quality, efficient and low toxic drugs, and reduce the dosage of drugs, so as to achieve rational use, and be careful to avoid drug injury accidents caused by overdose.

Breeding Ideas

1. New concept of polyculture: the scientific concept of polyculture tells us that not only four big fish can be polycultured, but also fish, shrimp, shellfish and crab can be mixed reasonably. For example, in the eel pond, the cochineal fish can feed on the scraps left by the eel; in the prawn pond, the small-sized perch can feed on the dead shrimp in time, effectively cutting off the transmission of pathogens. 2. Desalination and domestication: many mariculture species are widely salty, such as lice, Penaeus vannamei, etc., and can even survive in water without salinity. Moreover, the production speed of sea water varieties cultured in fresh water is often faster, and the diseases can be greatly reduced. 3. Northward migration of fish to the South: there are many excellent aquatic species in the north that have not been paid enough attention in the past. Practice has proved that many temperate fishes in northern China can fully adapt to the growth environment of the South after gradually domesticating from the seedling, even the annual average growth rate is faster than that in the origin, and the benefit is more significant. 4. Heterosis: the superiority of an excellent hybrid is beyond doubt, especially in the aspects of growth speed, disease resistance and adaptability to the environment. For example, hybrid catfish and hybrid sunfish are all good varieties that people like to talk about. 5. Imitation of wild culture: with the improvement of people's living standards, the quality requirements of aquatic products are higher and higher, and the pursuit of green food has become a fashion, which inevitably leads to the price of the same species of wild is many times higher than that of artificial culture. This phenomenon broadens the thinking for people in the breeding industry. If someone cross year polyculture the fish in the four big fish ponds, the quality of the fish is very close to that of the wild fish, and the price is very high. 6. Super size: among the common varieties, if we can produce super size varieties, it will be rare and expensive, and its market acceptance is often surprising. Such as super size sturgeon (more than 5 kg), the price and sales volume are very considerable. 7. Rotation: rotation has three advantages: first, it can reduce the deterioration of pond bottom quality; second, it can reduce disease infection; third, it can flexibly select breeding varieties according to market conditions. For example, in some areas, Penaeus vannamei was cultured in the first half of the year and Lateolabrax japonicus was cultured in the second half of the year.

Chinese PinYin : Jiang Xi Sheng Jiu Jiang Shi Peng Ze Xian Shui Chan Yang Zhi Chang