Is Linfen, Shanxi suitable for raising crayfish?

Brief introduction of freshwater crayfish culture technology

Freshwater lobster, scientific name crayfish, also known as lobster, lobster and red shrimp. This kind of shrimp originated in the United States and was introduced to China from Japan during World War II. Now it has been widely distributed in the middle and lower reaches of the Yangtze River. This shrimp belongs to fresh water shrimp in warm zone, which has strong adaptability, high reproduction rate, miscellaneous eating habits, fast growth, disease resistance, high temperature resistance and hypoxia resistance, and will not die after leaving water for several hours. Shrimp is tender and nutritious, and contains 8 kinds of amino acids necessary for human body, but its fat content is low, tropomyosin and paramyosin are more, and its edible parts are higher. Deeply loved by domestic consumers, the export volume is also increasing, the sales and purchase prices are rising, and the breeding prospects and benefits are promising.

Freshwater lobsters widely live in freshwater lakes, rivers, ponds, ditches, rice fields and other waters. Benthic organisms, plankton and various aquatic plants are delicious bait and grow well in these waters. Young shrimp live in shallow water or near pools, like to make holes, and sometimes hide in the hiding place of gravel aquatic plants. Usually, shrimp holes are dug in marshes around the water surface with more mud and reeds. Shrimp holes are generally round, inclined downward, about 30 cm deep, and wound in different directions. The habitats of freshwater lobsters often change with the seasons. When the water temperature rises in spring, shrimp mostly move in shallow water. When the temperature is not high in midsummer, it moves to deep water; Wintering in caves in winter. Freshwater lobsters molt, grow and breed in caves to avoid being hurt, and they prefer shade to light, and climb out of caves when the light is weak or dark. In the rainy season, freshwater lobsters often climb to land for activities. This kind of shrimp also has strong hunger tolerance, which can generally endure hunger for 3-5 days; Generally, if you don't eat for 20 to 30 days in autumn and winter, you won't starve to death. The optimum temperature for feeding is 25 ~ 30℃; When the water temperature is lower than 65438 05℃, the activity is weakened. When the water temperature is below 10℃ or above 35℃, the food intake is obviously reduced; When the water temperature is lower than 8℃, enter the wintering period and stop eating. The life span of freshwater lobster is generally 20 months for males and 24 months for females.

Freshwater lobsters usually mate and hold eggs from the end of 10 to March of the following year. Mating time is different in different waters. Eggs that mate too early are often immature, while eggs that mate too late are over-mature and aging. The suitable water temperature for mating is 22~25℃, and it is best not to fish in mating season so that it can hatch and reproduce with eggs. Freshwater lobsters mate in spring, summer and autumn and can lay eggs 3-4 times a year. Generally, parent shrimps with a body length of 7- 10 cm and a body weight of 15-30 g have 220-270 eggs, but the number of eggs varies greatly with individual size. Under normal circumstances, it takes 1~2 months from mating to spawning (that is, embryo development) for young shrimp, which requires a lot of physical strength, so it is necessary to strengthen the nutrition and cultivation of young shrimp. The suitable water temperature is 22~27℃ and the incubation time is 6~ 10 week. Before shrimp fry breeding, it is necessary to clean and disinfect the pond, filter the water, and then apply organic fertilizer to cultivate natural bait organisms for shrimp fry to eat. Generally, the stocking density of shrimp fry is1.5 ~ 200,000/200,000. If the shrimp fry are cultured by "soybean milk", the stocking density can reach1.6 ~1.8,000.

Second, lobster culture technology

Lobsters can be cultured in general ponds for breeding Macrobrachium nipponense, and they can also be cultured in general ponds. The culture technology after releasing the seedlings is similar to that of Macrobrachium nipponense, including early preparation, feeding feed and water quality management. However, we should pay attention to its construction habits and strengthen anti-escape measures. Lobster has strong endurance and high yield. At present, the market demand is also large, and the economic benefits of aquaculture are considerable. Now the most common shallow water rice cultivation is introduced as follows, and other cultivation methods can be referenced.

3. Freshwater lobster culture in rice fields

Freshwater lobsters raised in rice fields can generally reach 400-500 kg per mu, and can reach 600 kg when the yield is high. Shrimp farming in rice fields can eat aquatic organisms that consume fertilizers, such as weeds in the fields, which not only saves labor for weeding, but also eliminates mosquitoes and flies that harm people and animals. In addition, shrimp keep moving and foraging in the rice field, which can not only help the rice field loosen soil, live water and ventilate, but also increase dissolved oxygen in the field, and at the same time excrete a lot of feces through metabolism, thus achieving the effect of maintaining and increasing fertilizer.

1, Selection of Paddy Fields

To raise freshwater lobsters in rice fields, we should choose rice fields with abundant water sources, no drought or flood, fresh water quality, no pollution, fertile soil, good water retention and sufficient sunshine. Although the water quality of some mountain streams or springs is relatively poor and the water temperature is relatively low, if we can have a long process, or cross the rice fields where shrimps are not raised and then flow into the rice fields where shrimps are raised, the water temperature will rise, which is also suitable for raising shrimps.

2. Rice field transformation

In order to facilitate production management and daily feeding, the area between drainage ditches is generally regarded as feeding area. Dig a circulating buffer ditch with a depth of 0.5~0.6 m and a width of 1.0~ 1.2 m from the inside of the embankment, and turn up all the soil on the embankment, so that the height of the embankment can reach 0.8~ 1.0 m and the top width can reach 0.6. Ridge should be compacted and the inner slope should be smooth. At the same time, the inner side of the ridge top should be surrounded by a closed protective wall with plastic film. The height of the fence is 0.4 ~ 0.5m on the ground and 0. 1 ~ 0.2m underground ... The upper and lower entrances and exits shall be provided with escape prevention nets.

In order to facilitate shallow irrigation, drying, application of chemical fertilizers and pesticides or fishing in rice fields, shrimp ditches and ponds must be excavated in shrimp paddy fields. Shrimp ditch can be excavated after transplanting, and its opening mode should depend on the shape, area and direction of field drainage outlet. If the paddy field is small, it can be made into the shape of a "field"; If it is a long and big field, it can be opened into an inner "well" shape or an inner "field" shape, and the width and depth of the ditch are 0.3~0.4 meters respectively. Shrimp ponds can be opened at the intersection of shrimp ditches or at the four corners of fields, which are connected with the shrimp ditches. Shrimp ponds are generally 1.0m square and 0.8 ~ 1.0m deep.