According to the requirements of water temperature for cultured fish, it is classified as follows: for 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.
According to the aquaculture water conditions, fish species and specifications, water types and aquaculture measures, freshwater fish farming is divided into the following ways:
A. fish farming in still water and running water
B. monoculture, polyculture and polyculture
C. Fish culture in pond culture, paddy fields, rivers, lakes, reservoirs, cages, fences and factories, etc.
D. intensive cultivation, semi-intensive cultivation, coarse cultivation, etc.
The following is a summary of the important links of pond fish culture technology.
pond culture
Pond culture is a fish culture method used in most areas of China, and its current output accounts for more than 60% of freshwater fish culture, which has the characteristics of small investment, large income, quick effect and stable production.
Fish pond conditions
Area: Generally, the area of adult fish pond is 5_ 10 mu, which is easy to manage. 3_5 mu is suitable for parent fish pond, fry pond and fingerling pond.
Water depth: Generally, the water depth of a fish pond is 2 _ 3m. The suitable wintering pool in the north is1.5 _ 2m below the coldest and thickest ice layer. The water depth of fry pond and hatch pond should be1.0 _1.5m.. Fish ponds generally require a water depth of1.5 _ 2.0m..
Water quality: abundant water and good water quality are the fundamental conditions for fish farming.
Requirements for bottom material: The best bottom material of the pond is loam, sandy loam, followed by clay.
Preparation before stocking
Rest the pond, remove weeds and impurities at the bottom of the pond and level the pond.
Clear pond disinfection
Cleaning the pond by indigenous method: that is, draining water in winter, freezing, drying and blasting the bottom of the pond to remove enemy damage and improve the bottom material.
Drug pond cleaning: quicklime or bleaching powder can be used.
Water injection and water quality cultivation
After the pond is disinfected, fresh water can be kept until the toxicity of drugs disappears. Before the fish species are released, base fertilizer is put in 7_ 10 days to cultivate the water quality.
Fish stocking
Stocking large-scale fish species is a high-yield measure in pond culture. Large-scale fish species have the characteristics of strong disease resistance, high survival rate and rapid growth. Under the condition of pond rearing, grass carp generally rears fingerlings weighing 0.25 kg, which can reach 0.5_0.75 kg in autumn after four months. For example, those reared with 0.5_0.75 kg can grow to 1.0_ 1.5 kg. Generally, silver carp and bighead carp are put into the first-year-old fish, with the size of12 _18cm, which can reach 0.5 _ 0.75kg when they leave the pond. Other fish, such as carp, crucian carp and bream amblycephala, are stocked with first-year-old fish, the density is a little sparse, and the specification is about12 _14cm. After several months of breeding, the carp can reach the specification of 0. 5kg, bream amblycephala150 _ 350g, and crucian carp.
High-yield stocking mode:
According to many 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 by the above standard method.
2. Put the fish (such as crucian carp) with uniform specifications that can eat granular feed and the 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 a granular feed with complete nutrition and good physical properties according to the prescribed plan and method.
4. During the whole culture cycle, the water quality of the pond is always maintained at a level that will not cause fish stress reaction.
5. At the time of harvest, the individuals who mainly raise fish (80%) should be uniform in size and meet the market specifications.
Fish stocking density
The stocking density used in various places should be adapted to local conditions according to pond conditions. For the breeders who adopt the 80: 20 pond culture technology for the first time, the weight of the main fish at the time of harvesting per mu of water surface shall not exceed the following limits:
A. In a pond with limited aeration and unable to be flushed, the fish weight should be167kg;
B. In the pond with unrestricted aeration and restricted flushing, the fish weight is set at 267 kg;
C. In ponds where aeration and flushing are not restricted, the fish weight is set at 400 kg;
D. Together with 20% of the weight of fish culture, 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 size of the pond is expected to be 500g, the total number of fish raised in the ponds A, B and C will be 4 18, 666 and 800 respectively. Among them, the main fish culture accounts for 80%, and the fish culture accounts for 20%.
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. The maximum profit is achieved by maintaining the balance between production cost and the quality and quantity of fish species, feed quality and feeding quantity, and environmental quality. Scientific feeding management can be summarized as the following eight aspects:
Patrol the pond frequently and observe the dynamics of fish in the pond.
Patrol the pond every morning, noon and evening, and observe whether the fish have floating heads before dawn, and the degree of floating heads; During the day, we can combine feeding and water temperature measurement to check fish activities and feeding. In the hot season, when the weather changes suddenly, fish are prone to serious floating head, and the pond should be patrolled around midnight to stop serious floating head in time and prevent flooding.
Weed and decontaminate, keep the water fresh and the pond environment sanitary, and prevent diseases in time.
Master the 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 ample and comfortable activity space and a good living environment.
According to the weather, water temperature, season, water quality, fish growth and feeding situation, determine the feeding amount and do a good job in disease prevention in time.
Do a good job in the annual demand budget and distribution of feed and fertilizer.
Rational use of aerators, baiting machines and other fishery machinery, do a good job in maintenance and electricity consumption.
Pay attention to the market situation, arrange for leaving the pond in time, and do a good job of catching and releasing in turn where conditions permit.
Do a good job in keeping diary records and statistical analysis of ponds, including the following aspects:
Records of fish stocking, planned harvest and actual harvest
Feeding and fertilization records
Water quality management and fish disease records
Economic and Efficiency Analysis
These are the main points of pond culture's technology. It can be systematically summarized in eight words:
Water should have sufficient sources, good water quality, suitable water temperature and spacious water surface;
Species should have high-quality varieties and large-scale fish species with strong physique;
Bait should have comprehensive artificial compound pellet feed;
Dense density can obtain higher yield with higher density;
Mix and breed fatty fish properly;
Do a good job of catching and releasing fish in turn, or engage in rotation, that is, cultivate fish in the last crop and raise fish seedlings in the next crop;
Do a good job in disease prevention and treatment, and implement the principle of "early prevention of disease, prevention before disease, and prevention is more important than cure";
Manage meticulous daily management.