Crayfish Spring Rural Farming Precautions and Methods to Avoid Losses

After the beginning of spring next year, the parent crayfish that have lived in burrows for a winter will emerge in large numbers to forage in the pond. As the pond water temperature gradually rises and the parent crayfish gain nutrition after feeding, the juvenile crayfish begin to scatter and live freely in the pond, and the breeding density in the pond water body also increases rapidly. Therefore, management should be strengthened during the spring crayfish seedling cultivation process to ensure a good start for the whole year of crayfish farming. The relevant techniques compiled and edited are introduced below for reference only by crayfish farming operators.

I. Choose Good Water

For pond conditions, choose a location close to a water source, with sufficient water quantity, fresh water quality, no pollution sources, a quiet environment, supporting electricity, and convenient transportation. The pond should be rectangular, running east-west, with a large wind-receiving area and long sunlight duration. For ease of management, the area is generally best at 3300-6700 sq m (5-10 mu), the pond water depth at 1.2-1.5 m, the pond slope ratio at 1:3, and the soil texture is preferably clay loam, with a flat pond bottom. Two small mud ridges are set up in the pond (length is 3/5-4/5 of the pond length, width about 1 m, 5-10 cm above the water surface, with both ends not connected to the pond embankment, convenient for production boats to pass), increasing places for crayfish to dig burrows or rest. Around the pond, a 30 cm smooth calcium-plastic board is hung on the upper edge, fixed on the outside with wooden stakes, and a 50 cm high polyvinyl chloride mesh sheet is used as an anti-escape facility. The pond is built with an independent inlet and drainage system (the inlet and drainage outlets are sealed with filter screens), and is equipped with electromechanical equipment such as aeration and pumping.

II. Pond Clearing and Disinfection

Pond clearing and disinfection can effectively kill harmful organisms in the pond (catfish, loach, snakehead, snakes, rats, etc.), wild and miscellaneous fish that compete for food (carp, crucian carp, etc.), and pathogens. Quicklime and bleaching powder can be used, which are economical, affordable, and safe. The specific operation methods are: 1. Quicklime disinfection. Dry method disinfection: use 70 kg of quicklime per mu, dissolve in water and splash over the whole pond, and if conditions permit, rake it with a harrow, then after one week of pond drying, inject new water; disinfection with water: calculate per mu of water surface at a water depth of 1 m, use 130 kg of quicklime dissolved in water, then splash evenly over the whole pond. 2. Bleaching powder disinfection. After completely dissolving bleaching powder containing 30% effective chlorine, splash it evenly over the whole pond, with a dosage of 25 kg per mu.

III. Seedling Stocking

The stocking size is 2-3 cm, the density is 6000-8000 tails/mu, and the time is March-April. Choose the morning and evening of sunny days to stock the shrimp seedlings, and the shrimp seedlings stocked in the same pond in the same batch should have the same size. In order to fully utilize the water space and bait resources and increase pond productivity, about 200 silver carp and bighead carp fingerlings with a size of 100 g/tail can be stocked in combination per mu. Before stocking the seedlings, they need to be soaked and disinfected in a 3%-4% salt solution for 5-10 minutes to kill bacteria and parasites on the body surface.

IV. Bait Feeding

In the juvenile shrimp farming stage, the main feed is compound feed with a crude protein content of 36%-40%, and the daily feeding amount is 3%-5% of the total body weight of the pond shrimp. In addition, some fresh small miscellaneous fish need to be appropriately fed to meet the nutritional needs of juvenile shrimp development and growth; in the adult shrimp farming stage, the main feed is compound feed with a crude protein content of 30%-35%, and the daily feeding amount is 4%-5% of the total body weight of the pond shrimp. In addition, some cooked corn, soaked and germinated wheat, and fresh small miscellaneous fish need to be appropriately fed to improve the adult shrimp size and increase farming yield. Throughout the crayfish farming process, bait is fed twice a day, once before sunrise in the morning and once after sunset in the evening, with feeding in the evening as the main one, accounting for 60%-70% of the daily feeding amount. Place the bait on the pond bank or shallow shoals so that crayfish develop the habit of feeding at fixed points. The specific feeding amount should be comprehensively considered according to factors such as season, weather, water quality, water temperature, and the molting and feeding of crayfish, and scientifically controlled. Generally, it is appropriate if it is basically eaten up 2 hours after feeding.

V. Daily Management

The focus of daily management of shrimp ponds is patrolling the pond. The focus of pond patrolling is to observe the activity of the shrimp, changes in water quality, and weather conditions.

If crayfish rest during the day, are active at night, and feed normally, it indicates that the shrimp are healthy and the pond environment is good. If the shrimp come out to be active during the day, check whether there is any disease occurrence. If the shrimp body has no disease, and the feeding amount suddenly decreases, and a large number float to the surface during the day, it indicates that the water body is short of oxygen, and the water should be changed or oxygen should be added in time.

When observing the water, in addition to grasping the changes in water color and regulating water quality in time, you should also promptly repair damaged and leaking embankments and promptly salvage uneaten bait.