When will the crayfish of the crayfish family be released? How to vote? Mastering these six points will give you high output and high income!

Crayfish, also known as procrayfish, red crayfish and freshwater crayfish, have become an important economically farmed species in China in recent years. So when will it be planted? How to plant seedlings? The following one by one introduction, master these six points to let you high output and high income, crayfish farmers friends must look carefully!

Pond Management before Seedling release

1. Clearing miscellaneous fish and thoroughly removing the natural enemies of small and medium-sized lobsters in the pond when raising crayfish is a link that must be done before releasing shrimp seedlings. Many wild miscellaneous fish in crayfish ponds not only consume limited oxygen in the water, but also feed more than half of the feed may be put into the belly of these wild fish, which will greatly affect the normal food intake of crayfish. as a result, the crayfish is not growing and the yield is reduced. And the survival ability of wild miscellaneous fish is very strong, if you don't pay attention to it when cleaning up, you may breed a lot right away. Therefore, the effective elimination of wild miscellaneous fish in the pond can not only improve the utilization rate of feed, but also increase the output of crayfish in disguise. Therefore, whether the wild miscellaneous fish in the pond can be completely removed in the process of crayfish culture is a detail for farmers to increase production of crayfish. After the end of shrimp culture in the first season, release water to remove miscellaneous fish, it is best to dry up the flat water in the pond (or keep the water depth of 20cm ~ 30cm), and the cleaning effect is better in the ring ditch.

Control the water source: when injecting water into the crayfish pond, make a net sleeve with dense gauze silk, and put it at the outlet of the diving pump pipe when entering the water, which can effectively net and bring in wild miscellaneous fish and fish eggs when pumping water.

Kill fish eggs: every year from March to June is the prime time for crayfish to grow, and it is also the breeding season for crucian carp and wild miscellaneous fish. It is necessary to control the normal hatching of fish eggs in order to effectively increase crayfish production, so farmers can take the following relevant measures: ① found that there are fish eggs on the edge of the pool, immediately sprinkled with drugs (bleach, etc.) around the pool to kill; ② clean up water surface debris and pool weeds ③ hangs the grass handle from the bamboo pole and inserts it around the pond every evening. The grass handle is about 1 meter from the edge of the pool and 30 centimeters below the water line. The next morning, the grass handle is taken out and dried to kill the fish eggs attached to the grass handle.

Bait killing: you can mix medicine with Loach expanded feed, wait for the bait to dry and then feed it into the crayfish culture pond, you can kill wild miscellaneous fish and kill again 10 days later.

2. Disinfect tanning ponds

After the co-cultivation of shrimp and rice in the first season, there are two modes of shrimp culture in the second season: one is to keep the original Eloe algae for continued culture (this model does not require sunburn ponds); the other is to drain the water from the pond stalls, disinfect the sun ponds, and start breeding after planting aquatic plants.

The second mode is to disinfect the pond: ① drains the water on the stall and then disinfects it with lime; after ② disinfection, the pond is usually sunburned for 15 to 20 days until the pond is cracked.

3. Water grass planting (lantern bulb grass)

What we are talking about here is the link of replanting lantern bubble grass after drying the pond, and the part of keeping the original Elodea aquaculture is not elaborated.

After basking in the pond, add about 20 cm ~ 30 cm of fresh water (at first, the water level should not be too deep, which will affect the rooting of lantern bulbs), and detoxify them with organic acids (at this time, lantern pickles are mainly transplanted from other ponds).

Planting method and matters needing attention of lantern bulb grass: ① planting method is the same as planting Elorella, planting lantern bubble grass 15 jin ~ 20 jin per mu according to 4 meters × 4 meters, and the water grass planted should be pressed with soil to prevent it from floating and difficult to take root. ② planted aquatic plants for 3 ~ 5 days, and used long grass fertilizer to supplement nutrition in time to promote its rooting and growth. it should be remembered that no chemical fertilizer was used in the middle of culture, and the application of chemical fertilizer could easily lead to the increase of ammonia nitrogen salt in pond water quality and affect the growth of farmed animals. ③ should often observe the growth of aquatic plants after planting aquatic plants. Lantern bubble grass is easily eaten by worms. Once grass and insects are found, do a good job of killing insects in time. ④ with the growth of lantern bulb grass, slowly add new water to keep the grass 20 centimeters below the surface to prevent the high temperature from burning and affect the growth of the grass.

Second, seedling release time

The planted lantern bulb grass will take root steadily and grow vigorously (about 20 ~ 25 days) before it can release seedlings. Once the aquatic plants do not take root stably, the growth is not obvious, they begin to cast seedlings, and under the ravages of shrimp seedlings, they gradually wither and even die. In the second season of high temperature period, once there is no role of aquatic plants, the failure rate of culture is very high.

According to the survey, most farmers began to invest a large number of seedlings in mid-June, and the survival rate of the better situation is only about 20%. During this period of time, shrimp fry in intensive ponds began to appear on the market in large quantities, so the price of shrimp fry fell, and farmers saw such a good price situation, so they began to enter the fry. June is the peak of lobster disease, so the survival rate of releasing seedlings is not high, and even the dead shrimp seedlings will affect the disease of lobsters with large size around the ditch, resulting in serious losses to farmers.

The correct release time should be after July, after the disease period of lobster in July, although the price of shrimp seedlings has increased, but the survival rate is higher.

Lobster seedling delivery requirements are neat specifications, complete appendages, disease-free and injury-free, and foot release at one time. Wash in 5% salt water bath for 5 ~ 10 minutes before stocking to kill parasites and pathogenic bacteria. For the purchased shrimp species, due to long-distance transportation from the water, the seedlings should be soaked in the pond water for 1 minute before entering the pond, lifted and shelved for 2 ~ 3 minutes, and then soaked for 1 minute, repeated for 2 ~ 3 times, so that the body surface and Gill cavity of the seedlings can absorb enough water before restocking, which can improve the survival rate. Breeding parent shrimp was released in autumn, and 500 artificially selected lobster parent shrimp were released per mu before and after September, with a female-to-male ratio of 3 ∶ 1.

III. High temperature period management and water quality control

The main results are as follows: 1. the high temperature period has the characteristics of high temperature, muggy, sudden change of weather and so on. according to this climatic characteristic, the culture management of crayfish should be adjusted accordingly. Whether one or two seasons of crayfish are cultured in ponds or in rice fields, water quality management, stress management and feeding management in high temperature culture period are important links in crayfish culture period.

2. Water quality control

Deepen the water level at the right time to lower the water temperature. Timely addition of water is not only to improve the water quality, but also to reduce the water temperature of the pond. As the saying goes, "raise big fish in deep water". For crayfish, proper water depth can prevent the water temperature from rising rapidly and do no harm to the growth of aquatic plants. In general, the water level of crayfish culture pond in high temperature culture period is 1.2 m-1.8 m, a small amount of water is added for many times, each time the amount of water is 3 cm ~ 5 cm, which is not higher than that of crayfish hole.

Control the blackening of water quality. Crayfish culture ponds will blacken the water quality during the high temperature period due to the decay of Elodea, and also due to the application of drugs to control moss until the moss dies. After the crayfish culture water quality blackens, it will cause the crayfish to get on the grass or go ashore, so it is very important to change the bottom and fertilize water regularly.

Control the water quality is dark green. In crayfish ponds with low growth or low vitality of aquatic plants, algae often multiply excessively due to the accumulation of organic pollutants in high temperature periods, resulting in thick green water quality and serious outbreaks of cyanobacteria. Bacteria in high temperature period is the best choice for water transfer, and bacteria are often added to the pond, which can not only decompose the organic impurities in the water for algae absorption, but also decompose the aging algae in the water and prevent the aging phenomenon of algae.

Prevent the sediment from blackening. Blackening of sediment and rancidity of sediment are common phenomena in crayfish culture in high temperature period, which is related to the accumulation of organic dirt such as excessive bait, crayfish excreta and decaying residues of aquatic plants in the sediment of culture water. The measures to prevent the blackening of sediment are suggested to change the bottom water transfer with 8 ~ 10 times "Chi Di'an + clear Water detoxification'an".

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