At the beginning of the new year, most crab culture areas began to release seedlings one after another. The earlier the seedlings were released, the earlier the crabs shed their shells. Therefore, some experienced farmers have completed the work of releasing seedlings before the Spring Festival, so as to shell the crabs as soon as possible after they enter the pond. The following work should be done about imitating seedlings:
0 1 scientific planning combines the experience and lessons of previous years and the market demand, and defines this year's objectives, stocking mode, stocking density, management methods and risk response measures, adheres to scientific planning, and cannot blindly follow suit.
The selection of crab seedlings and crab species should follow the principles of green shell, white belly, strong physique and complete appendages. To judge the quality of crab seedlings, we should first observe the cleanliness of the body surface and whether there are obvious problems such as grinding claws, ulcers and ciliates. Focus on the hepatopancreas and intestines of crab seedlings, such as whether the hepatopancreas is white, heartbroken and red. The cleanliness of gills can also accurately feedback the quality of water environment in the process of crab seedling cultivation, and turning over is also a common observation method when selecting crab seedlings.
Pay attention to the work of spitting crab seedlings before putting them into the pond. Generally speaking, spitting includes two links: spitting after crab seedlings leave the pond and spitting in the stocking pond. Especially for crab seedlings that need long-distance transportation, spitting water after leaving the pond is particularly critical. If the spitting is not complete or the time is too short, the oxygen consumption of crab seedlings will increase during transportation or even the seedlings at the bottom of the seedling bag will be deprived of oxygen, which will obviously reduce the physique of crab seedlings and affect the final survival rate.
It is also essential to soak the crab seedlings before putting them in. On the one hand, there will be stress reactions in the process of crab seedling release, such as: water environment change stress, temperature stress, etc. On the other hand, in the process of artificial seedling selection and transportation, crab seedlings will also have some mechanical damage, such as residual limbs and broken claws. Therefore, the work of soaking seedlings should focus on improving the anti-stress ability of crab seedlings and avoiding bacterial infection induced by mechanical injury.
05 seedling release model
When releasing seedlings, put them in shallow water on the shore or on a foam boat and let them climb into the water by themselves. This method of releasing seedlings can effectively distinguish whether the failure of releasing seedlings is due to the crab seedlings themselves or the water quality. If a small number of seedlings can't climb into the water by themselves, it means that there is something wrong with the seedlings themselves, and we can directly eliminate these seedlings. If the seedlings can't stay in the water after climbing into the water repeatedly, it may be that there is a problem with the water quality and it is necessary to detect the water quality in time.
Mr. Liu and Mr. Duan, crab farmers located in Huai 'an, Jiangsu Province, have successively encountered the problem of crab seedling climbing, and the reasons are unknown. After careful investigation, Youjiu technicians resolutely suggested using Youjingling whole pool spraying to solve this problem, and the results were harvested the next day after use. The role of Youjiling in improving the edge climbing of crab seedlings has been fully reflected.