What does crayfish culture eat?

Crayfish culture should pay attention to the following matters:

First, pay attention to the pond conditions. The pond for crayfish culture should not be too deep, generally not more than1.5m. The ridge of the pond should have a certain slope, which is conducive to creating a water environment with different depths and different water temperatures, and at the same time, it can make full use of light energy, improve the water temperature and promote the growth of crayfish. Crayfish have a strong ability to dig holes and escape. The roof should be compacted and tamped, and there should be no caves. The width should be greater than 1.5 meters, and the periphery should be surrounded by anti-escape facilities such as asbestos tiles, especially the water inlet and outlet should use double-layer filters to prevent cultured shrimp from escaping. The newly opened pond should also be covered with a layer of 60-80 mesh polyethylene net around the slope or in the middle of the pond ridge.

Second, we should pay attention to planting aquatic plants. Many ponds for crayfish culture are transformed from fish ponds, and there are no aquatic plants. In fact, crayfish need aquatic plants as much as shrimp and river crabs. One of the reasons for the failure of some farmers is that they have not planted aquatic plants. Aquatic plants can not only provide hidden habitat and shelling places for crayfish, but also purify water quality, increase dissolved oxygen and provide fresh natural plant bait for crayfish. The biggest advantage is to reduce crayfish killing each other. The aquatic plants mainly include hydrilla verticillata, Elodea nuttallii, Sophora alopecuroides and Alternanthera philoxeroides, accounting for 20% to 30% of the culture area.

Third, we should pay attention to feeding. Crayfish is omnivorous, likes to eat animal bait, and is greedy and eats a lot. The lack of bait is easy to cause cannibalism. At present, the internal organs of chickens, ducks, pigs and other livestock and poultry are cheap, and some farmers feed the internal organs of livestock and poultry as a whole, but they are not evenly flapped, which leads to crayfish fighting with each other when eating, and the water body turns black and stinks, which is easy to cause diseases and lead to the failure of some farmers. It is necessary to adhere to the combination of fine and green, and flexibly grasp the feeding amount according to the feeding situation.

Fourth, we should pay attention to regulating water quality. Although crayfish have strong viability and tolerance to hypoxia, the quality of fresh water is still one of the key factors for high yield of crayfish. In the environment with low dissolved oxygen, crayfish's appetite decreases and its growth is slow, which is easy to cause escape and disease. Once a large number of crayfish are found crawling ashore or floating on grass heads, water should be changed immediately, especially in the middle and late stages of culture, and water should be changed 1 ~ 2 times a week to keep high dissolved oxygen in the water.

Fifth, we should pay attention to disease prevention. Crayfish has strong disease resistance and is not easy to get sick in natural waters. After high-density culture in ponds, improper management can easily lead to diseases, mainly fiber disease, black gill disease and hemorrhagic disease. We should adhere to the principle of putting prevention first, and splash the whole pool with quicklime (20ppm) regularly and use it alternately. Crayfish is very sensitive to pesticides, so pesticides such as trichlorfon and diphacinone should be banned, and a large amount of pesticides should also be prevented from flowing into shrimp ponds, causing unnecessary losses.

Aquatic plants such as water hyacinth, water peanut, water hyacinth and water bamboo are planted around the pond, and the coverage is generally 1/3 of the water surface of the pond, which is beneficial for lobster to shade and breed plankton that lobsters like to eat. Before 10- 15 shrimp larvae are released, generally, fully decomposed manure such as 100-200 kg of pig manure is applied to each mu of water surface to cultivate plankton, and a proper amount of organic debris is provided as shrimp larvae feed. Small fish and minced meat are put in within 3 days after seedling release, and small miscellaneous fish, minced meat or compound feed are put in after 3 days, 1 month. When the shrimp seedlings grow to 6-7 cm, they can all be fed with crushed snails and mussels and appropriate plant feed such as wheat, bran, corn and cake or compound feed. The daily feeding amount is based on satiety, eating and leaving no residual bait. Generally, crayfish and adults are fed at 15%-20% of their body weight, which can be adjusted according to their eating conditions. Feed twice a day, once in the morning and once in the evening, and the feeding amount at night accounts for 70%-80% of the daily feeding amount. Bait should be thrown around the pond, and properly dispersed, mostly in places where lobsters are concentrated to facilitate their feeding.

The location of the farm is very special. Try to choose a place with sufficient water and good water quality, because the number of crayfish cultured artificially is often large and the pond density is high, so it is necessary to replenish fresh water regularly, adjust the water quality and maintain a certain depth. Generally speaking, the water depth should reach1.5m. In addition, farms should not be built in low-lying areas to prevent floods.

Do a good job of escape prevention facilities to prevent lobsters from fleeing. Once a large number of crayfish flee, it will not only bring economic losses to itself, but also destroy the ecological environment of the surrounding waters, because it is very aggressive and threatens small fish, shrimps, snails, mussels, aquatic insects, etc. It is an omnivore and can eat the roots, leaves or algae of some aquatic plants. Therefore, if there are too many crayfish in a certain water area, it will easily affect the survival of other organisms and thus destroy the ecosystem.

It is very important to measure the water temperature frequently. Crayfish is very sensitive to water temperature: when the water temperature is 15℃~30℃, it can move normally; Below 15℃, the activity decreased and holes began to appear. After the hole was dug, they got into the hole and lived in it. Below 10℃, they seldom go out for food; Below 8℃, enter the overwintering period, do not eat, and the growth stagnates; Below 3℃, those lobsters that haven't made a good hole will wait to die. Therefore, it is necessary to measure the water temperature of aquaculture ponds frequently and take corresponding measures.

Provide adequate food. Crayfish will shed their shells during growth. Without the protection of hard shells, their self-defense ability is very weak. If food is scarce, crayfish without shells can easily become the target of other similar hunting. In addition, crayfish must make holes to survive the winter safely. It takes a strong body to make a hole. How to make a hole if you are not full?

Plant some aquatic plants in the aquaculture pond. Crawfish like to find some hidden places as hiding places when they shell, and aquatic plants are their best habitat. In addition, aquatic plants can also purify water. Of course, you can't plant too many aquatic plants, which generally account for 1/5 of the pond area, otherwise it will absorb too many nutrients in the water.

Do a good job in disease prevention. Judging from my situation here, crayfish are most likely to get gill rot, and the diseased lobster has black gill filaments, local mildew and high mortality. How to prevent this disease? I asked some lobster farmers in Shaoxing, and they said that food residues in ponds should be removed frequently to keep the water fresh, and bleach solution can also be used to splash it, which can have a good therapeutic effect.