Cultivation techniques of hairy crabs
Current management
Adhere to the sustainable and healthy farming mode and strengthen the detection of water environment quality. Through ecological breeding of reed, the wetland vegetation is protected, so that the breeding environment in this area has strong water quality regulation and purification functions, thus realizing the healthy breeding of river crabs in the Yellow River estuary. The second is to strengthen the management of water environmental quality testing. By sampling and testing reed wetland culture area regularly or irregularly, the physical and chemical indexes of water environment in the culture area can be grasped in time, and the culture water can meet the environmental requirements of crab culture in the Yellow River estuary. After stocking crab larvae, patrol the pond once every morning and evening to observe the growth and feeding of crabs, regularly test the water quality in the culture area, and deal with problems in time. Salinity: 0? ~30? Optimum temperature 15℃~30℃, optimum temperature 22℃~25℃, dissolved oxygen above 5mg/L, pH 7.5~8.5, ammonia nitrogen below 0. 1mg/L, and hydrogen sulfide below 0.01mg/L. ..
Water quality regulation
No medicine is used in the breeding process, and basically no water is changed. In case of water quality deterioration or rainstorm, the water quantity should be adjusted or supplemented in time, and the changed water quantity depends on the situation. In production, we strictly follow the pollution-free control technology and do not use pesticides and hormones. And directly introduce the Yellow River water for natural cultivation. When it is hot in summer, according to the water quality, we will change the water from time to time, each time the water depth is 10 cm ~ 20 cm, and then drain and irrigate.
Capture and sell
Every year from September to June, 5438+ 10, hairy crabs are caught by trapping with lights or inserting nets in various canals. Captured adult crabs should be kept in cages for more than 2 hours, filtered with mud, packaged in bags and transported to the market for heat preservation.
Scientific breeding of hairy crabs
1, prepare seedlings and strengthen escape prevention facilities.
Use the search net to stop the escape. There should be no tall crops near the crab pond. It is best to make an arc around the escape wall. When cleaning the pond by sterilization and disinfection, remove excess sludge, leaving only about 10 cm sludge, and sprinkle quicklime on the whole pond, with the dosage of 200 yuan per mu? 250 kg, in order to achieve the purpose of thorough cleaning, disinfection, impurity removal, sterilization and improvement of bottom material. Seven days after taking the medicine, remove the dirt with water 1 time, and then bask in the pool for 3? Add water after 5 days.
2. Plant aquatic plants well
To cultivate hairy crabs, aquatic plants should be planted first, as the saying goes? Crab size, see water plants? It shows that aquatic plants are an important factor affecting the fishing specifications and yield of hairy crabs. During the high temperature period in summer, aquatic plants can not only provide habitat, shelter, shelling places and plant bait for Yangcheng Lake hairy crabs, but also play the role of shading, reducing water temperature and improving water quality. Water hyacinth, POTAMOGETON crispus, PUCCINELLIA tenuiflora and other aquatic plants that hairy crabs like to eat are the best, accounting for 1/3 of the crab pond. 1/2。 Aquatic plants are one of the natural bait for hairy crabs, which can play a very good role in purifying water quality. You can also add a proper amount of snails.
3. Maintain good water quality
Water environment is the first restrictive factor of hairy crab breeding, and the quality of water quality is directly related to the benefit of breeding. In the process of hairy crab breeding, the water quality should be kept fresh, and it is best to raise crabs with micro-running water where conditions permit. Water with high organic content is easy to lack oxygen, and a large amount of moss is produced in the pool, which affects the growth of hairy crabs. Every 15 in summer? 20 days, and calcium superphosphate (2? 3ppm), quicklime (10? 15ppm) to adjust the pH of water, supplement calcium for hairy crabs and promote the growth of crab molting (note that the application time of both should be 3? 5 days). In addition, the high temperature period is best every 3? Change the water for 5 days 1 time, and the water change amount shall not exceed 1/3 of the original pond water, and keep 1? When the water level is 1.5m, the transparency shall be controlled at 35? 40 cm. Because of the large temperature difference between day and night in autumn, the water quality is easy to deteriorate, so Qin Ying changed water in early autumn. With the decrease of water temperature, the number of water changes should be gradually reduced, and the transparency should be kept at about 45cm, and the water level should be kept at 1? 1.5cm or so, to ensure the water temperature to be stable for wintering.
4. Reasonable stocking
Before release, the crab seedlings should be disinfected and evenly separated according to their size. When released, put the crab into the water with a purse seine to adapt to the environment 1 month, and then remove the purse seine. What should crab farming do in general? Shisan? ,? Temporary support? Principle. That is, suitable density, timely stocking, moderate specifications and temporary cultivation before stocking. When stocking, the water should not be too deep. 1.5? 2 meters is appropriate; The temperature is 20 degrees? 25 degrees is the best.
5. Carrying capacity
In an environment with abundant aquatic plants and fresh water quality, the specifications per mu are generally around 300, so that hairy crabs have enough room for survival and growth. Generally speaking, the stocking time of crab species is from the end of February to March every year. If the seeds are planted too early, the casualties will be heavier in winter, and the water temperature will rise too late, some river crabs will shell, which will affect the survival rate of the pond.
Step 6 feed scientifically
Summer is the peak season for hairy crabs in Yangcheng Lake, so we should seize the opportunity to put enough good bait to ensure their rapid growth. At this stage, the proportion of plant bait (such as bean cake, wheat, pumpkin, etc.). ) should be appropriately increased to help Yangcheng Lake hairy crabs accumulate physical strength and prevent precocious puberty. Autumn is the fattening season of hairy crabs in Yangcheng Lake, so high-protein bait such as snails, mussels, animal leftovers and miscellaneous fish should be appropriately increased. Feeding twice a day, and the daily feeding amount accounts for 5% of the weight of Yangcheng Lake hairy crabs? 8%, feeding time is 8 o'clock? 10:00, 17:00? 18: 00 is appropriate, in which the feeding amount in the evening accounts for 70% of the whole day, and the feeding amount is slightly more than last time. The specific feeding amount should be flexibly controlled according to the weather, water quality and the feeding situation of Yangcheng Lake hairy crabs. Yangcheng Lake hairy crabs are rampant all over the world.
Disease control of hairy crabs
Summer and autumn are the high incidence seasons of crab diseases, and improper management can easily lead to large-scale diseases. The combination of oral administration and external use is used to prevent crab diseases on a regular basis, and the external drug is Jia Jia Xie Jing 'an; The internal medicines include Radix Isatidis and desquamation. In summer, the water temperature is high, the water quality is easy to deteriorate, and the crab has weak disease resistance. It is best to sprinkle 1 time quicklime every half month; Usually, the whole pool should be sprinkled with bleaching powder and crab paste from time to time; It's best to feed 3 at this stage? 4 times, and cooperate with changing water and sprinkling lime to adjust water quality. Should we focus on hairy crabs after beginning of autumn? Shaking? Prevention and treatment. Can chlorine dioxide, dichlorohydantoin and other drugs overflow the whole pool, combined with new prevention and control? Shaking? Take orally drugs such as virus buster and ketongling for prevention and treatment for one week.