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.
According to the conditions of aquaculture waters, fish species and specifications, water types and aquaculture measures, freshwater fish culture 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.
The following summarizes 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 pond, fry pond and fish pond.
Water depth: Generally, the water depth of fish ponds is 2 _ 3m. The suitable wintering pond in the north is under the coldest and thickest ice layer 1.5 _ 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.
Preparation before stocking
Let the pond rest, 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, eliminating enemy damage and improving the bottom material.
Cleaning the medicine pool: quicklime or bleaching powder can be used.
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.
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 specification of 0 .5 kg, namely, bream 150_350 g and crucian carp 18.
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 uniform fish (such as crucian carp) and uniform filter-feeding fish (such as silver carp) that can eat granular feed 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 prescribed 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 size of individuals (80%) who mainly raise fish should be unified and meet the market specifications.
Fish stocking density
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%.
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:
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 and the degree of floating heads before dawn; 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.
Weed and decontaminate, keep the water fresh and the pond clean, and prevent diseases in time.
Master the water injection and drainage of 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.
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 to leave the pond in time, and do a good job of releasing the fish in turn where conditions permit.
Make diary records and statistical analysis of the pond, 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 technical points of pond culture. It can be systematically summarized in eight words:
Water should be abundant, with good quality, suitable water temperature and spacious water surface;
Species should have high-quality varieties and large-scale fish species with strong physique;
The bait should have a comprehensive artificial compound pellet feed;
Close planting can obtain higher yield with higher density;
Appropriate polyculture of fatty fish;
Take turns to catch and release fish, or engage in crop rotation, that is, raise fish in the previous crop and raise fish seedlings in the next crop;
Do a good job in disease prevention and control, and implement the policy of "early prevention, prevention before illness, and prevention is more important than cure";
Manage meticulous daily management.
Second, cage culture technology:
1 introduction and popularization of cage culture technology Jr. cage culture technology Jr. is a small-scale high-density cage culture technology, which was introduced to China from the United States on199/kloc-0. 1in the summer of 1994, Dr. Smither, an aquaculture expert from Auburn University, came to our province to hold the first training course on cage culture technology. Since then, this technology has been gradually popularized in our province. Huangshan, Anqing, Maanshan, Hefei, Bengbu, Huainan, Lu 'an and other cities have a certain scale of aquaculture. According to incomplete statistics, the promotion of aquaculture in the whole province reached15000m3 in/99.
2 Characteristics and advantages of small cage fish culture The main differences between small cage fish culture and traditional cage fish culture are as follows: First, traditional cage fish culture is small, with an area of tens of square meters, a depth of about 2 meters, and a volume of tens to 200 cubic meters, while small cage fish culture is usually 1-4 cubic meters. Second, the density of fish species in small cages is high and the yield per unit area is high. Thirdly, fish culture in small cages depends entirely on full-price pellet feed, and high-quality varieties that are marketable can be selected according to market demand.
Small cage fish culture has many advantages in production: First, because of its small size, it can be set in reservoirs, lakes, rivers and ponds with large area and deep water. Second, due to the high yield of small cages, which are located in large waters, the combination of intensive cultivation in small cages and proliferation in large waters can quickly improve the total output and production level in large and medium waters. Third, the small cage is easy to make, simple to operate and easy to master the breeding technology, which is very suitable for one household to operate.
Material, manufacturing method and setting of small cage
3. 1 Materials required for cage. There are mainly polyethylene net, steel frame, bamboo, iron wire, mesh wire, shading cloth, feed pipe, etc.
Polyethylene mesh is the main material for making small cages. Generally, the mesh size is 3×3-3×4, the mesh is 2-3 cm, and it is single layer. In addition, the bottom of the box needs to be covered with a layer of dense mesh to prevent feed loss.
The diameter of the steel bar is 0.8- 1cm, and it can be welded into a cube or cuboid frame according to the required size of the box, which can open the cage as a whole and avoid the cage from floating up at the same time, so as to maintain the maximum volume of the cage.
The diameter of Phyllostachys pubescens is 8- 10 cm. The length is determined according to the area of the cage, tied into a box and tied to the top of the cage. Because bamboo is hollow and buoyant, it mainly acts as a float. In addition, the feeding tube is generally made of bamboo, the length of which is equivalent to the depth of the cage, but the bamboo seam in the middle should be opened. Iron wire and mesh wire play a reinforcing role. The shading cover cloth can be made of ordinary rain-proof cloth, which is black and durable. The area is equivalent to the area of the cage.
3.2 Manufacture of cage. Firstly, the steel frame is welded, and the mesh is tightly fixed outside the frame to form a fully enclosed hexahedral cage. A layer of dense mesh is added to the bottom of the box, and the dense mesh is 10 cm higher than the bottom of the box. Add a bamboo frame to the upper opening of the box, erect a feed pipe in the center of the cage, and the lower opening of the feed pipe is 10- 15cm away from the bottom of the box, and then cover it with a shading cloth.
3.3 Setting of small cages. It requires good water quality and a wide area, and large and medium-sized reservoirs and waters with a certain flow are ideal. Cage culture areas should avoid waterways, flood gates and water inlets where mountain torrents may rush in summer.
Small cages should be arranged in an I-shape, and the direction is perpendicular to the direction of micro-flow in the water area, which is convenient for water exchange in the box. The spacing between each column is not less than 20m, and the spacing between each box is more than 2m.
The boxes are connected by iron wire or steel rope, and both ends are fixed on the shore or fixed by iron anchors and big stones.
Variety, specification, density and release time of small cage culture
4. 1 variety. At present, the main species that can be cultured in small cages are carp, tilapia, channel catfish, herring, crucian carp, bream bream, grass carp and so on. All localities can flexibly choose suitable varieties according to local market demand, fry source and other factors.
4.2 specifications. The small size of fish species is not conducive to the production and feeding of feed, and also affects the listing of commercial fish. Therefore, fish species are generally required to be 50-75g/ tail, and crucian carp and Megalobrama amblycephala can be smaller, but not less than 30g/ tail.
4.3 Release density. The suitable yield level of carp and tilapia cultured in small cages is about 50-200 kg per cubic meter/kloc-0 and 80- 100 kg for crucian carp, and the density of 300-400 fish per cubic meter is better. Fish should be of the same size.
4.4 release time of fish species. Carp, crucian carp and bream can be released when the water temperature is stable at 12- 15℃, and tropical fish species such as tilapia should be released when the water temperature is stable at 20℃. It is worth noting that the cage should be put into the water about 10 days before the fish enters the box, so that some algae can grow on the net coat and form a biofilm, which can reduce the scratches on the fish and avoid getting sick.
Fish are healthy, and disinfected with 3%-4% salt water or 8- 10mg/L malachite green solution for 10- 15 minutes to prevent fish from getting sick.
5 feed and feed
5. 1 feed. Need comprehensive and reasonable nutrition. Generally, protein content in tilapia feed is 28%-32%, carp feed is 30%-36%, and grass carp feed is 28%-30%, and amino acids should be balanced. The particle size of feed should be adapted to the size of fish, such as 50-75g in weight and 2mm； in particle size; Weight 75- 150g, particle size 3-4mm; The weight exceeds 150g, and the particle size is 4-5mm. Feed should be stable in water, 10 minutes.
5.2 Feeding requirements. The fish can be fed the next day after they are in the box. The feeding amount depends on the size of the fish and the water temperature. The water temperature is below 20℃, the fish weight is between 500g and the daily feeding amount is between 2.5%- 1%; 2 1-25℃, the daily feeding amount is 3.5%-1.5%; At 25-30℃, the daily feeding amount is 5%-2%. With the growth of fish, samples should be taken from 10 ~ 15 days to analyze the growth and adjust the feed consumption.
Feed should be concentrated in the feed pipe. When the water temperature is low, feed 1-2 times every day at 8-9 o'clock and 2-3 o'clock in the afternoon. Feed it 3-4 times a day when the water temperature is high, at 8-9 am,11-kloc-0/2 pm, 2-3 pm and 5-6 pm.
6 Daily management should be managed by special personnel. Generally, one person can manage 20-25 small cages 1 m3 or 15-20 cages with 2-4 m3. Observe the feeding and activities of fish every day, check the growth regularly, and find out the reasons and take improvement measures in time when there is no food, dead fish or abnormal growth. It is necessary to strengthen safety awareness and do a good job of "four precautions", that is, flood prevention, network disconnection and fish leakage, theft prevention and disease prevention. Make production records at ordinary times, and record in detail the time, quantity, weight, specifications, feed dosage, weather changes, varieties and dosage of disinfection, disease prevention and treatment drugs, final output, specifications and other raw materials for summing up experience and cost accounting at the end of production.
The above contents are for reference only.
The following are some videos of freshwater fish culture techniques around cages for reference only:/playlist _ show/ID _ 2719952.html.