The traditional collocation ratio of silver carp and bighead carp is 3: 1, that is, the three silver carp bands are 1 bighead carp, which are 75% and 25% respectively. According to the production practice, in the stocking structure of silver carp and bighead carp, when the proportion of silver carp is less than 20% or more than 80%, the growth rate of bighead carp is faster, and when the proportion of silver carp is between 20% and 80%, the growth rate of bighead carp will be inhibited. When bighead carp is the main fish culture, a small amount of silver carp should be added or not stocked. ?
2, fried stockings
In the past, the stocking specification of bighead carp in lakes and reservoirs was generally around 13.2㎝, but under modern technical conditions, it needs 0. 15-0.5kg/ tail or even 1.0kg.
Stocking time: it should be carried out in winter or early spring when the water temperature is 5 ~ 10℃. At this time, it is beneficial to the high-density transportation of fish species and can reduce casualties in transportation; The activity ability of fish species and fierce fish is weakened, and the harm of fierce fish to stocking fish species is relatively reduced.
Stocking location: It should be selected in the fertile bay upstream of the reservoir, with shallow water depth, shelter from the wind and abundant sunshine. In this way, staying away from the spillway and spillway tunnel downstream of the reservoir can reduce the escape opportunity of stocked fish, shorten the adaptation time to the large water surface environment, accelerate the growth and improve the survival rate.
Stocking weather: Choose sunny days, not windy, snowy or frozen days.
Quarantine and disinfection: Quarantine and disinfection of fish diseases must be carried out before the fish stocks are put into storage. It is strictly forbidden to store fish with infectious diseases in the warehouse.
Caution: After the long-distance transported fish species are transported to the reservoir, they should be slowly added into the fish container with reservoir water, and then slowly put into the reservoir when the temperature difference between the water in the container and the reservoir water is not great. After being put into the reservoir, the stocking personnel should also stand on the edge of the reservoir or on the boat, gently stir the reservoir water with paddles, and slowly drive the fish to swim to the big water surface. ?
3. Water quality control
Regulating water quality has three functions:
The first is to improve water quality. After the beneficial bacteria in microecological preparations enter the water body, they play the roles of oxidation, ammoniation, denitrification, phosphorus dissolution, vulcanization and nitrogen fixation. And quickly decompose organic matter such as excrement, residual feed and animal remains. For cultured animals, the concentration of ammonia nitrogen and nitrite in water body is effectively reduced;
Secondly, the salt after the decomposition of organic matter provides a good ecological environment and nutrition for the growth and reproduction of unicellular algae, and the photosynthesis of unicellular algae provides dissolved oxygen for the oxidative decomposition of organic matter and the respiration of cultured organisms.
Forming a benign ecological cycle, maintaining and creating good water quality conditions, can maintain the stability of water quality for a long time, achieve water, fertilizer and stability, and is conducive to the healthy growth of breeding objects. At the same time, it can also increase zooplankton and beneficial algae in the aquaculture water, expand the source of bait and reduce the production cost.
The third is disease prevention. Applying beneficial bacteria with microecological agents to aquaculture water can not only repel pathogenic bacteria, maintain the ecological balance of microecological flora in water, and avoid aquatic organisms from being attacked by pathogenic bacteria, but also produce antibacterial substances and various immune promoting factors, activate the immune system of the body, strengthen the rebound reaction of the body, enhance the disease resistance and improve the survival rate. ?
Food use
Analysis of eating habits
In the past, bighead carp mainly fed on zooplankton under the low-level culture conditions of natural environment. According to the study on the feeding habits of bighead carp, a large amount of organic fertilizer must be provided to cultivate large plants, zooplankton and humus. When the water body is short of large plants,
Humus in organic fertilizer is used as the main bait for silver carp. However, under the condition of rich water, plankton are mainly linear diatoms, dinoflagellates, cryptoalgae, rotifers, cladocera, copepods and other species with individuals larger than 50 microns, and these are the filtering objects of bighead carp. ?
Fertilizer use
Principle: By putting organic fertilizer, inorganic fertilizer and biological compound fertilizer into large water surfaces such as reservoirs and lakes, the contents of main nutrient elements such as nitrogen and phosphorus in water bodies are increased, the primary productivity of water bodies is improved, and the yield of bighead carp is increased.
The earliest fertilizer used in fishery was original organic fertilizer, such as manure and compost, and later inorganic fertilizer was used. The original organic fertilizer has comprehensive nutrition, low effective components and slow fertilizer efficiency, which limits the production of fish. Inorganic fertilizer has high effective component content, short fertilizer efficiency and single component. Small green algae and cyanobacteria are mainly cultivated, which is beneficial to the growth of silver carp and not ideal for bighead carp culture.
Modern bio-organic fertilizer for fishing, which is made by decomposing traditional organic fertilizer with modern biotechnology and adding inorganic fertilizer properly, contains not only a large number of macro elements such as nitrogen, phosphorus and carbon, but also balanced trace elements, a large number of humus, peptides, beneficial bacteria and fertilizer efficiency enhancers. It has the functions of fertilization, improvement and water control.
It is also especially suitable for breeding plankton that bighead carp likes to eat, such as macroalgae, rotifers, cladocera, copepods and so on. This provides a material basis for high-yield culture of bighead carp.
Extended data
Living habits
1, feeding habits
There are a lot of plankton growing in the water. The main ingredients of food are rotifers, cladocera of crustaceans, and various algae. In terms of the number of individuals, algae are often more than animal food. But in terms of quantity, animal food still accounts for the main component.
2. Growth
The growth rate of bighead carp in the Yangtze River is faster than that in the Pearl River, because the average biomass of plankton in the Pearl River is obviously less than that in the Yangtze River, although the optimum temperature period is two months longer than that in the Yangtze River. However, the growth of bighead carp in artificial fertilization ponds varies greatly due to climate and biological abundance of bait in water.
3. Reproduction
Under natural conditions, the gonads of bighead carp, like other domestic fish, can develop in still water, but the maturity of eggs requires ecological conditions such as river water environment and rising water level.
In the main and tributary of the Yangtze River, from the end of April to the beginning of July every year, due to the rainfall in the main stream of the basin, the water level rises, and when the water temperature reaches 65438 08℃, the gonad of the parent fish matures rapidly in the upstream process, and it changes from stage IV to stage V for spawning and fertilization. After fertilization, the fish eggs drift along the river and hatch into fry.
According to the survey, the mature age of bighead carp is 3-4 years old in the Pearl River basin and 4-5 years old in the Yangtze River basin. The fecundity of bighead carp is high, the maturity coefficient is generally about 20%, and the relative fecundity is between 1 10- 160 eggs/g body weight. Absolute fertility increases with weight gain, which is positively correlated.
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