The latest scientific crayfish culture technology

Because of the popularity of crayfish among the public, some people think that crayfish farming is very profitable, so many farmers and other people outside the industry are willing to cultivate crayfish, so the technical essentials of crayfish farming are extremely important to them.

The latest scientific crayfish culture technology

1. Seedling cultivation

The cultivation pond covers an area of 20-40 square meters and a water depth of 0.6-0.8 meters. You can also choose ponds with good water quality near the source to build drainage and escape prevention facilities. The pond was strictly disinfected before seedling release, and plankton was cultivated with basic fertilizer to provide open bait, and the area of transplanted aquatic plants accounted for 30% of the water surface. There were 10-150000 young shrimps per mu, which were mainly fed with natural bait, soybean milk and surimi properly, and artificial diet with the increase of individuals.

2. Pond culture

Put 1-15000 young prawns per mu, regularly sprinkle quicklime to increase the content of calcium in the water, increase the amount of feed at night, mainly compound feed.

3. Rice field culture

The fields with good water quality, no pollution sources, strong water conservation capacity, convenient drainage and irrigation, and no flooding are selected to raise shrimp in rice fields. Shrimp culture ditches should be dug along the inside of the ridge of rice fields. The ditches are 1.5 meters wide and 1 meters deep, and the field ditches are also excavated in the middle of the field. 5 meters, the area of shrimp culture ditch and field ditch accounts for about 20% of the total area of rice field. The ridge is more than 3 meters wide and 1 meter high. One meter away from the ridge of the field, hit a 1.5-meter-high pile every 3 meters, set up with bamboo, plant melons, beans, gourds and so on on the ridge of the field. After the vines are on the shelf, they play a role of shade and summer shelter in the hot summer. In shrimp ditches and fields, it is necessary to transplant aquatic plants, such as bitter grass, verticillium verticillata, goldfish algae and other submerged plants. The coverage of aquatic plants should be 30%, and sporadic and scattered is better, which is conducive to the smooth flow of water in the shrimp ditch. An anti-escape wall is built around the field with plastic film, cement board, asbestos tiles or calcium plastic board to prevent crayfish from escaping.

4. Seedling stocking

Crayfish should be released to test the water, and only after the water is safe can the shrimp be released.

There are two methods of crayfish stocking: one is to put the shrimp directly into the rice field in early September after rice harvest and let it reproduce on its own. according to the actual situation of rice field culture, crayfish with an individual of more than 40 grams per mu are generally 20 kilograms, with a female-to-male ratio of 3: 1.

Second, after the rice seedlings were planted in May, 1500mur2000 shrimps or 30kg / mu of young shrimps with specifications of 2-4 cm were put in. Crayfish in stocking, we should pay attention to the quality of young shrimp, the same field stocking specifications should be as neat as possible, full release at one time. When stocking young shrimp in sunny mornings or rainy days, wash them in 3%-4% salt bath for 10 minutes to disinfect.

5. Suitable area

Ponds, lowlands, rivers and rice fields can all be farmed.

The living habits of crayfish

Crayfish are omnivores, mainly eat plants, small fish, shrimp, plankton, benthos, algae can be used as its food. Crayfish do not have a strong ability to reproduce. Crayfish reproduce once a year.

Crayfish is very viable, in addition to Asia, Europe and Africa are also its home, so it has become a world-class delicacy. It is eaten in Europe, Africa, Australia, Canada, new Zealand and the United states, where Louisiana claims to produce 90% of the world's crayfish, and locals eat 70% of them. In addition to some morphological and habitual advantages, crayfish's worldwide "success" is partly due to its tolerance to polluted environment.

Morphological characteristics of crayfish

The crayfish body length refers to the extension length (cm) from the base of the eye stalk to the end of the tail segment of the crayfish, and the total length refers to the extension length (cm) from the top of the forehead to the end of the tail limb. People used to think that the brewed shrimp specification refers to the length of the brewed shrimp. Crayfish consists of 21 body segments of head, chest and abdomen, with 19 pairs of appendages, body surface with hard carapace, head with 5 segments, chest with 8 segments, head and chest as a whole, called head and chest. The head and chest is cylindrical, with a triangular forehead sword at the front; the forehead sword surface is smooth and flat, the middle depression is groove-shaped, and the front end is sharp and aggressive; there is an arc-shaped neck groove in the middle of the head and chest nail, with rough particles on both sides.

There are seven segments in the abdomen, and there is a flat caudal segment at the back end, which forms the tail fan together with the appendages of the sixth ventral segment. There are 5 pairs of chest and foot, the first pair is chelate and thick, the second and third pairs are pincer-shaped, and the last two pairs are claw-shaped. There are 6 pairs of abdominal feet, the first pair of female abdominal feet degenerated, the first two pairs of male abdominal feet evolved into calcareous junctions, and each pair of appendages had their own functions. The sexually mature individuals of crayfish are dark red or dark red, while the immature individuals are light brown, yellowish brown, reddish brown, and sometimes blue. The common crayfish is 4.0-12.0cm in length.

Species harm of crayfish

Crayfish are raised all over the world and form a large number of wild populations. China was introduced from Japan in the 1930s and 1940s, and Japan was introduced from the United States earlier, mainly for food and pets. Crayfish are often mixed in crop (such as rice) fields. There is no need for artificial hatching, once the original seed is released in the pond, it can be self-sustaining, and there is no need to release the original seed after harvest. The escaping individual survived by digging a hole in the dam. They can survive in temporary water bodies, have a wide range of feeding habits, and establish populations very fast and easy to spread.

It is a great threat to local fish, crustaceans and aquatic plants, destroying the local food chain; directly damaging crops (especially aquatic and semi-aquatic crops such as rice) and natural vegetation because of its root system; burrowing causes the loss of irrigation water and field destruction; because crayfish have miscellaneous feeding habits, it has a certain impact on the flowering of fish fry and the cultivation of 1-year-old fish, and harms the artificial breeding of young clams.

Because crayfish have strong adaptability, strong stress resistance, extensive feeding habits and fast population proliferation, they often cut off crops, especially rice crops, and may compete with local freshwater crayfish species.

We have been paying attention to the delicacy of crayfish, but we have never understood that crayfish are so aggressive in the living environment, which also leads to difficulties for other creatures to survive, and in serious cases, it may lead to the reproduction of other aquatic organisms, thus destroying the balance of the ecological environment and the food chain.