Getting the Six Key Points Right in Pond Crayfish Farming Can Increase Profits

Speaking of crayfish, many people may already be drooling. Those in the know are surely well aware that although there are many ways to prepare crayfish on the market, most are still based on the spicy crayfish served as a late-night snack, so the market demand for crayfish is very large.

Getting the Six Key Points Right in Pond Crayfish Farming Can Increase Profits

1. Get the fry stocking point right.

The stocked shrimp fry should be uniform in size, robust in constitution, strong in activity, with intact appendages, and free of injury and disease. The size of stocked shrimp fry should reach 0.8-1.0 cm, and the size of shrimp seed should be above 3 cm. The stocking density should be reasonable, and the stocking size within the same pond should be consistent. The method for stocking shrimp fry is to first put the fry into a plastic basin, slowly add a small amount of pond water until the water temperature in the basin is close to the pond water temperature, and add salt at a concentration of 3%-4%. Let the fry soak and disinfect for 3-5 minutes, then slowly release them into the pond along the edge.

For winter stocking, choose a sunny morning; for summer and autumn stocking, choose a sunny early morning or a rainy day. When stocking brood shrimp, soak them in 3%-5% salt water for 5-10 minutes to kill parasites and pathogenic bacteria. For shrimp seed purchased from elsewhere, after long-distance transport and a long time out of water, when stocking, first soak the shrimp seed in pond water for 1 minute, then take them out and place them at the pond edge for 2-3 minutes. Repeat this soaking and removing 2-3 times, so that the body surface and gill cavities of the shrimp seed absorb enough water, then slowly put the shrimp seed into the pond, which can increase the stocking survival rate. To make full use of the farming water space, some silver carp and bighead carp (bighead carp and silver carp) fingerlings can be stocked in combination, with a stocking size of 100 g per fish, stocking 50 fish and 100 fish per 667 sq m respectively. Reasonably stocking some silver carp and bighead carp can not only increase the yield per unit area and improve farming economic benefits, but also make full use of the bait resources in the pond and improve the pond water quality.

2. Get the feed feeding point right.

Crayfish are omnivorous, especially fond of animal feed, and are greedy by nature with a large food intake. The feed fed should be comprehensive in nutrition, and the feeding amount should be moderate. If the feeding amount is insufficient, it will affect growth and may even cause them to kill each other; if the feeding amount is too large, it will waste feed and also pollute the water quality; if the feed nutrition is not comprehensive, it will cause malnutrition and affect growth. In high-density farming, mainly feed crayfish compound feed. When shrimp fry and shrimp seed just enter the pond, a large amount of rotifers, cladocerans, copepods, and aquatic insect larvae can be cultivated in the farming pond by fertilizing and topdressing for them to eat; in the juvenile shrimp stage, the protein content of the compound feed fed should be greater than 30%, and in the adult shrimp farming stage the feed protein content should be above 26%. Feed twice a day, once in the morning and once in the evening, feeding before sunrise in the morning and after sunset in the evening, with the evening feeding as the main one, accounting for 70% of the daily feeding amount;

The daily feeding amount is mainly determined according to the total weight of crayfish in the pond. From March to April and after October, the daily feeding amount is 1%-3%; from May to October is the normal growth season for crayfish, and the daily feeding amount is about 5%. Generally, when the weather is fine, feed more; in high-temperature and muggy weather, continuous rainy weather, or when the water quality is too dense, feed less; when a large number of shrimp are molting, feed less, and after molting, feed more. Feeding should adhere to the "four fixed" principles, namely fixed location, fixed quantity, fixed time, and fixed quality. The specific feeding amount should be flexibly controlled according to the weather, water temperature, water color, and the growth of the crayfish, and it is appropriate that they eat their fill, finish the food, and leave no residual bait.

3. Get the molting period management point right. The molting period is a critical time for crayfish growth, and doing a good job of management during the molting period is especially important. The following four aspects should mainly be done well:

First, maintain good water quality. Frequently add fresh water and keep the water quality fresh and free from pollution, so that crayfish molt in a good water environment, which can shorten the molting time and benefit the development and growth of crayfish;

Second, ensure feed nutrition. After each molt, crayfish lose a large amount of calcium, phosphorus, iron, and so on. Therefore, the compound feed should contain indispensable components such as calcium, phosphorus, and iron, and the auxiliary animal and plant feeds fed should be reasonably matched;

Third, plant and maintain aquatic plants well. Plant aquatic plants such as Hydrilla verticillata, Elodea, and Vallisneria in the farming pond, with a coverage rate above 60%. Crayfish like to molt in shallow water or among grass clumps. After completing the molt, the soft-bodied shrimp will immediately drill into the aquatic plants to hide, in order to avoid being eaten by their own kind or enemies;

Fourth, eliminate enemy organisms. The main enemies of crayfish include water rats, frogs, water birds, and some ferocious carnivorous fish. These animals can all prey on crayfish, and are even more harmful to crayfish whose bodies are soft after molting, so measures should be taken in time to eliminate them. For carnivorous fish, during water intake, they can be kept out of the farming pond by screening with fine nets. For rodents, rat traps and rat cages can be used to catch and kill them; for birds, some colored strips and scarecrows can be set up at the pond edge to frighten and drive them away. For frogs, the most effective way is to catch them manually at night.

Fifth, feed medicated bait. During the molting period of crayfish, use as little medicine as possible and do not use chemical preparations. Add photosynthetic bacteria, immune polysaccharides, multiple vitamins, molting hormone, monocalcium phosphate, etc. to the feed to make medicated bait for feeding, which can enhance the constitution of crayfish, reduce the occurrence of shrimp diseases, and promote the healthy growth of crayfish.

4. Get the water quality regulation point right.

Maintaining good water quality is conducive to the healthy growth of crayfish. Add fresh water once every 7-10 days, adding 20 cm each time, to keep the water quality fresh and clean; use quicklime to disinfect the water body once every 10-15 days, adjusting the pH value to 7.5-8.5. After quicklime is slaked into slurry with water, splash it over the whole pond while hot, with a dosage of 10 kg per 667 sq m of water surface, so that the water quality remains weakly alkaline; use photosynthetic bacteria, EM bacteria, or substrate improvers and other microecological preparations once a month to reduce harmful substances such as ammonia nitrogen, nitrite, and hydrogen sulfide in the pond, improve water quality and substrate, and control the pond water transparency at 35-40 cm.

Normally, the aeration equipment should be turned on frequently to keep the dissolved oxygen in the pond water above 5 mg/L. Wei Ailiang, a crayfish farming demonstration household in the fishery science and technology household program in Jinhu County, Jiangsu Province, installed a dissolved oxygen controller on the aeration equipment, setting upper and lower limits according to the dissolved oxygen needs of crayfish to automatically control the automatic start and stop of the aeration equipment, so that the dissolved oxygen in the shrimp pond always remains in the set optimal state, allowing crayfish to grow in a comfortable and happy environment with very good results. The author believes that this technology is worthy of wide promotion and application. 5. Get the crayfish quality point right.

Strictly implement the production standards for pollution-free aquatic products, strictly prohibit the use of prohibited drugs and inputs, strengthen feeding management, and improve the farming quality, quality, and farming benefits of crayfish. 6. Get the timely harvesting point right.

After about 2 months of rearing, the shrimp body size of crayfish can reach above 50 g. At this time, harvesting can begin. Catch the large-sized shrimp for market sale, reduce the density of crayfish in the pond, and promote the rapid growth of small-sized crayfish. Harvesting tools include shrimp cages, ground cages, and so on.

Feeding and Management of Crayfish Farming in Rice Fields  

1. Feed feeding  

For shrimp farming in rice fields, try to achieve fixed time, fixed location, fixed quantity, and fixed quality feeding. Crayfish have omnivorous feeding habits and eat meaty feeds (small miscellaneous fish, snail meat, river meat, fish meat, earthworms, animal offal, silkworm pupae), concentrated feeds (sugar cakes, corn, wheat, barley flour), and green feeds (various aquatic grasses, vegetable trimmings, etc.). The daily feeding amount is generally 4%-6% of the shrimp body weight. In the early stage, feed twice a day, once in the morning and once in the afternoon; in the later stage, feed once at around 18:00.  

2. Water and fertilizer management  

After crayfish are stocked, field ditch management is a very important link. The water depth in the rice field should be kept at about 20 cm. Water is generally added at 10:00-11:00, keeping the introduced water temperature close to the rice field water temperature.  

During rice field management, the water level should also be regulated according to the requirements of rice field drying and pest control. In the middle growth stage of rice, dry the field appropriately, thereby increasing light, increasing root vitality, sterilizing, and raising temperature. Normally, flood control, drainage, and escape prevention should also be done well. After heavy rain, promptly check whether the water inlet and outlet and the shrimp-blocking facilities are intact, to prevent shrimp from escaping.  

3. Disease and natural enemy control  

Adhere to the principle of giving priority to prevention and combining prevention with control. During the growth of rice, pesticides must be sprayed to control pests. After spraying pesticides, replace with fresh water, thereby providing the necessary ecological environment for the growth of rice and crayfish. For rice disease control, mainly choose high-efficiency and low-toxicity pesticides, adopt spraying methods, and let the medicine fall on the leaf surface. The application time should preferably be 8:00-9:00 on a windless sunny day. Once enemies are found, eliminate them promptly, and at the same time install fine-mesh nets at the water inlet and outlet to prevent enemy organisms from entering.

Advantages of Farming Crayfish in Rice Fields  

First, increase production and income;  

Second, crayfish can eat wild weeds and aquatic organisms in the field without eating rice seedlings, and can also eliminate harmful larvae including mosquitoes, which can play a role in weeding and pest control;  

Third, the swimming and foraging of fish and shrimp help loosen the soil, activate water, and ventilate the rice field, which can increase the dissolved oxygen in the field water. At the same time, through metabolism they discharge a large amount of feces, which has a fertilizing effect.

Winter Farming and Stocking Techniques for Crayfish  

1. Stocking should be carried out on sunny or rainy days, avoiding exposure to sunlight.  

2. Externally purchased crayfish. If the time out of water is long, they should be slightly treated before stocking. That is, soak the shrimp seed in pond water for 1-2 minutes, lift it out and place it for 2-3 minutes, then soak it again for 1-2 minutes, repeating 2-3 times, so that the shrimp absorb enough water before stocking, which can increase the survival rate.  

3. Stocking density. Stock 150 kg-250 kg per mu, with a size of 16-20 shrimp per kg. Stocked crayfish are required to be robust in constitution, uniform in size, and intact in appendages, and should be stocked all at once to avoid stocking in batches, so as to reduce mutual killing.  

4. Overwintering ponds can be stocked with an appropriate amount of silver carp and bighead carp to regulate water quality and improve feed utilization.

As more and more people farm crayfish now, many new farming models have also appeared. To achieve development in the farming industry, one must keep pace with the times and continuously develop new technologies and methods in order to achieve better results.