Freshwater fish culture is a way to raise and manage fish species in water, or to breed in water to protect fish resources, so as to produce high-yield fish. At present, there are more than 30 species of freshwater fish culture in China. According to the characteristics of cultured fish, water quality conditions and culture measures, freshwater fish culture is divided into the following ways:
According to the requirements of water temperature for cultured fish, it can be divided into: warm-water fish culture, the general water temperature is 15_30℃, such as carp, grass carp, silver carp, bighead carp, crucian carp and bream; Cold water freshwater fish culture: generally, the appropriate temperature is 10_20℃, such as rainbow trout and freshwater fish. Hot water fish culture: generally, the suitable temperature is 18_30℃, such as tilapia and freshwater pomfret.
2. According to the conditions of aquaculture waters, fish species and specifications, water types and aquaculture measures, freshwater fish farming can be divided into the following ways:
A. fish farming in still water and running water
B. monoculture, polyculture and polyculture
C pond culture, fish culture in paddy fields, rivers, lakes, reservoirs, cages, fences, factories, etc.
D. intensive cultivation, semi-intensive cultivation, rough cultivation, etc.
3. The following is an overview of the important links of pond culture technology.
pond culture
Pond culture is a kind of fish culture method adopted in most parts of China. At present, the output accounts for more than 60% of freshwater fish culture, which has the characteristics of small investment, large income, quick effect and stable output.
Fish pond conditions:
Area: The average adult fish pond area is 5_ 10 mu, which is convenient for management. 3-5 mu is suitable for parent fish ponds, fry ponds and fish ponds.
Water depth: Generally, the water depth of fish ponds is 2 _ 3m. The suitable wintering pool in the north is under the coldest and thickest ice layer1.5-2m. The water depth of the fry pond and incubation pond should be1.0—1.5m. Generally, the water depth of fish ponds is1.5-2.0m..
Water quality: Adequate water quantity and good water quality are the fundamental conditions for fish farming.
Requirements for the bottom material: the bottom material of the pond is preferably loam, sandy loam, followed by clay.
4. Preparation before stocking
Let the pond rest, remove weeds and impurities at the bottom of the pond and level the pond.
A. Cleaning and disinfection of ponds
Cleaning the pond by indigenous method: that is, draining water in winter, freezing, drying and blasting the bottom of the pond, eliminating enemy damage and improving the bottom material.
Cleaning the medicine pool: quicklime or bleaching powder can be used.
B. Water injection and water quality cultivation
After disinfection in the pond, fresh water can be kept until the toxicity of the drug disappears. 7_ 10 days before the fish species are released, the base fertilizer is released to cultivate the water quality.
5. Fish stocking
Stocking large fish species is a high-yield measure for pond culture. Large fish species have the characteristics of strong disease resistance, high survival rate and fast growth. Grass carp usually rears fingerlings weighing 0.25 kg in ponds, which can reach the specification of 0.5_0.75 kg in autumn after four months, and can grow to 1.0_ 1.5 kg when reared in ponds. Generally, silver carp and bighead carp are annual fish, with the size of 12_ 18 cm, which can reach 0.5_0.75 kg when they leave the pond. Other fish, such as carp, crucian carp and bream bream, are all annual fish, the density is a little sparse, and the specification is about 12_ 14 cm. After several months' rearing, the carp can reach the specifications of 0 .5 kg, namely, bream 150_350 g and crucian carp 18.
6. High-yield stocking mode:
According to years of breeding experience and scientific summary, various localities have formulated many stocking models, which are not listed here. Only the 80: 20 stocking technology is introduced here:
1). Prepare the pond according to the above standard method.
2) Put fish (such as crucian carp) with uniform specifications that can eat pellet feed and filter-feeding fish (such as silver carp) with uniform specifications into the prepared pond, accounting for 80% and 20% of the total output respectively.
3) Feed 80% fish with granular feed with comprehensive nutrition and good physical properties according to the specified plan and method.
4) During the whole culture cycle, the water quality of the pond is always kept at a level that will not cause stress reaction of fish.
5). At the time of harvest, the individuals of main fish culture (80%) should be of the same size and meet the market specifications.
7. Stocking density of fish
The stocking density used in various places should be adapted to local conditions according to the pond situation. For the first time to adopt the 80: 20 pond culture technology, the main fish weight per mu of water surface at harvest shall not exceed the following limits:
A. In a pond with limited aeration and unable to be washed, the fish is reset to167 kg;
B. In the pond with no restriction on aeration and no restriction on washing, the fish weight is set at 267kg；;
C. In ponds where aeration and flushing are not restricted, the fish weight is set at 400 kg;
D. With the addition of 20% fish culture weight, the total fish production weight of Class A, B and C ponds is 209 kg, 333 kg and 400 kg respectively.
E. If the average pond size is 500g, the total fish culture in grade A, B and C ponds is 465, 438+08, 666 and 800 respectively. Among them, the main fish culture accounts for 80%, and the secondary fish culture accounts for 20%.
8. Feeding management in pond culture.
Good management is an important factor for the success of aquaculture. The ultimate goal of breeding is to get the maximum profit. By maintaining the balance between production cost and the quality and quantity of fish species, feed quality and feeding quantity, and environmental quality, the profit is maximized. Scientific feeding management can be summarized as the following eight aspects:
A. Patrol the pond frequently and observe the dynamics of fish in the pond. Patrol the pond every morning, noon and evening to see if the fish float before dawn and to what extent; During the day, you can combine feeding and water temperature measurement to check fish activities and feeding. In hot season, when the weather changes suddenly, fish are prone to serious floating head, so the pond should be patrolled around midnight to stop serious floating head in time to prevent flooding.
B weed and decontaminate, keep the water fresh and the pond clean, and prevent diseases in time.
C. Do a good job of water injection and drainage in the pond, keep a proper amount of water, prevent waterlogging and drought, and prevent fish from escaping. According to the situation, water should be injected once every 10_ 15 days to supplement evaporation consumption, so that fish can have sufficient and comfortable activity space and good living environment.
D. According to the weather, water temperature, season, water quality, fish growth and food intake, determine the feeding amount and do a good job in disease prevention in time.
Budget and allocate the annual demand for feed and fertilizer.
F. Use fishery machinery such as aerators and baiting machines reasonably, and do a good job in maintenance and power consumption.
G. Pay attention to market conditions, arrange to leave the pond in time, and do a good job of catching and releasing in turn where conditions permit.
Make diary records and statistical analysis of the pond, including the following aspects:
Fish stocking and planned harvesting, actual harvesting records, feeding and fertilization records, water quality management and fish disease records, and economic benefit analysis.
These are the technical points of pond culture. It can be systematically summarized in eight words:
A. Water should be abundant, with good water quality, suitable water temperature and spacious water surface;
B. the species should have high-quality varieties, large fish and strong physique;
C. The bait should have a comprehensive artificial pellet feed;
D. the higher the density, the higher the yield;
F, mixing and properly polyculture the fat fish;
G. catch fish by turns, release them by turns, or engage in rotation, that is, raise fish in one crop and fry in the next;
Do a good job in the prevention and treatment of diseases, and implement the policy of "early prevention, prevention before illness, and prevention is more important than cure".