How to farm crayfish? Mastering eight key steps is crucial

Crayfish is a creature with extremely strong vitality. In just a few years after being introduced to our country, it has taken root everywhere. By now, crayfish has become the star of night markets and has excellent farming prospects. So how can crayfish be farmed well? Master the eight key steps, and you need not fear farming crayfish poorly!

1. Master the step of planting aquatic plants

Regenerating aquatic plants should be planted in the shrimp pond, mainly submerged plants (Elodea, Hydrilla verticillata, Vallisneria, etc.), supplemented by floating plants (water spinach, duckweed, etc.), and appropriately combined with some emergent plants (Artemisia, reeds, etc.). Plant Elodea on shallow slopes, plant Hydrilla verticillata, Vallisneria, water spinach, duckweed, etc. in deep water, and plant reeds, wild rice stem, etc. on shallow flats. The aquatic plant coverage rate should reach 50%. If too sparse, supplement promptly; if too dense, cut back manually.

2. Master the step of stocking seedlings

The crayfish seedlings stocked should be uniform in size, robust in constitution, strong in activity, complete in appendages, and free of injury and disease. The size of stocked shrimp seedlings should reach 0.8-1 cm, and the size of crayfish seed should be above 3 cm. Stocking density should be reasonable, the stocking size in the same pond should be consistent, and sufficient stocking should be done at one time. Before stocking crayfish seedlings, they need to be soaked in 3%-4% salt water for 5-10 minutes to kill pathogenic bacteria and parasites. In order to fully utilize the aquaculture water space, increase aquaculture output, and improve farming benefits, some silver carp and bighead carp fingerlings can be stocked in combination, with a stocking size of 100 g per fish and a density of 100 fish per mu. Stocking silver carp and bighead carp fingerlings in the aquaculture pond can also play a role in purifying water quality.

3. Master the step of feed feeding

Crayfish is an omnivorous shrimp species, especially fond of animal-based bait, and is greedy by nature with a large food intake. Therefore, the feed fed must be comprehensive in nutrition and moderate in feeding amount. If the feeding amount is insufficient, it will affect growth and may even cause mutual killing; if the feeding amount is too large, it will cause feed waste and also pollute water quality; if the feed nutrition is not comprehensive, it will cause malnutrition, lead to incomplete molting, and affect growth.

In high-density farming, feeding crayfish compound feed is the main method. When shrimp seedlings and shrimp seed just enter the pond, a large amount of rotifers, cladocerans, copepods, and aquatic insect larvae can be cultivated in the aquaculture pond by fertilizing and topdressing for them to feed on; in the juvenile shrimp stage, the protein content of the compound feed fed should be greater than 30%; in the adult shrimp farming stage, the feed protein content should be above 26%. Feed twice daily, once in the morning and once in the evening. Feed in the morning before sunrise and in the evening after sunset, with evening feeding as the main feeding, accounting for 70% of the daily feeding amount; the daily feeding amount is mainly determined according to the total weight of crayfish stored in the pond. From March to April and after October, the daily feeding amount is 1%-3% of the total shrimp weight. From May to October is the normal growth season for crayfish, and the daily feeding amount is about 5% of the total shrimp weight. Generally, when the weather is clear and fine, more should be fed; during high temperature and muggy, continuous rainy weather, or when water quality is too dense, less should be fed; 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 weather, water temperature, water color, and the growth condition of crayfish, with the suitability being eating enough, finishing the food, and leaving no residual bait.

4. Master the step of water quality regulation

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, with an amount of 10 kg per mu. The method is to add water to make a slurry and then splash it over the whole pond while hot, adjusting the pH value to between 7.5 and 8.5, so that the water quality remains weakly alkaline; regularly use microbial preparations such as EM water conditioning king and substrate improver to reduce harmful substances such as ammonia nitrogen, nitrite, and hydrogen sulfide in the pond, improve water quality and substrate, and control pond water transparency at 30-40 cm; usually, aeration equipment should be turned on frequently to keep dissolved oxygen in the pond water above 5 mg per liter.

5. Master the step of molting management

The metamorphosis of crayfish larvae, regeneration of walking legs, and their growth always proceed together with molting. Only after crayfish shed their hard outer shells can they achieve the purpose of growth. Therefore, the molting period is a critical moment for crayfish growth, and doing a good job in management during the molting period is particularly important. The following three points should mainly be done well: first, regulate water quality well and keep the water fresh. Second, feed sufficiently and with comprehensive nutrition. Third, maintain aquatic plants well; if too abundant, cut them back manually, and if insufficient, supplement promptly.

6. Master the step of disease prevention and control

Disease prevention and control in crayfish should adhere to the policy of “prevention first, treatment auxiliary, prevent before disease occurs, and treat early when disease occurs.” Strict pond clearing and disinfection, stocking high-quality seedlings, creating a good ecological environment, feeding fresh feed, and regularly feeding medicated bait and other technical measures can effectively prevent the occurrence of shrimp diseases. Once crayfish become diseased, fishery drugs permitted by the state with high efficiency, low toxicity, and small side effects should be used to treat the disease early according to the symptoms.

7. Master the step of preventing enemy intrusion

The main natural enemies of crayfish include water rats, frogs, water birds, and some ferocious carnivorous fish. These animals can all prey on crayfish and should be eliminated promptly by taking measures. For carnivorous fish, during water intake, they can be kept out of the aquaculture pond by blocking and filtering with fine mesh nets. For rodents, mouse traps and mouse cages can be used to capture 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 method is manual capture at night.

8. Master the step of timely harvesting

After about 2 months of rearing, crayfish body size can reach more than 50 g. At this time, harvesting can begin. Large-sized shrimp can be caught and sold on the market to reduce the density of crayfish in the pond and promote the rapid growth of small-sized shrimp. Harvesting tools include shrimp cages, ground cages, etc.