Aquatic plants eaten by crayfish
Crayfish is an omnivorous animal, which likes to eat animal bait such as fresh miscellaneous fish, earthworms, snails and internal organs of livestock and poultry, fork likes to eat plant bait such as soybeans, bean cakes, bran, corn and fresh aquatic plants, and can also be fed with compound feed for shrimp, but the feeding habits are slightly different at different development stages.
In the natural environment, the newly hatched larvae of crayfish are nourished by their own preserved yolk, and soon after that, they feed on small zooplankton such as rotifers. With the growing of individuals, they feed on larger zooplankton, benthos and plant debris. Adult shrimps eat both animals and plants, mainly plant debris and animal carcasses, as well as water worms, chironomid larvae, small crustaceans and some aquatic insects.
In the artificial rearing environment, crayfish feed on rotifers, cladocera, copepods and aquatic insects larvae in the juvenile and juvenile stages, and eat both animal feed and plant feed in the adult stage. In the rapid growth stage of crayfish from August to10, more bran, bean cake and green feed were fed, and animal feed was properly fed. 11~1February crayfish were mainly fed with animal feed before overwintering.
Therefore, under natural conditions, crayfish will eat grass, such as phytoplankton and tender parts of aquatic plants; Under artificial feeding, food can be adjusted according to the feeding characteristics of crayfish, so that crayfish grow fast.
Cultivation of aquatic plants in crayfish culture ponds
(1) transplanting method. Hydrilla verticillata, Elodea nuttallii and other aquatic plants with stems are suitable for transplanting, and they are generally planted in winter and spring. The method is to cut the aquatic plants into small pieces with the length of15 ~ 20cm. Like transplanting rice seedlings, evenly transplant bundles of cut grass into the mud at the bottom of the pond, with the plant and row spacing controlled at about 20cm respectively. After transplanting, fill the shrimp pond with water for 20~30 cm, and gradually deepen the water level after the aquatic plants grow all over the pond.
(2) throwing planting method. Floating-leaf plants such as water lilies and water lilies can be wrapped in soft mud and directly thrown into the pond, so that their roots can grow in the sediment and their leaves can float on the water.
(3) Transplanting method. The emergent plants such as Zizania latifolia and Sagittarius sagittarius should be transplanted by roots. When transplanting, the damaged leaves and slender and inferior seedlings should be removed. The transplanting position can be in the shallows near the pool, and the root water of the seedlings should be between 10~20 cm, and the density should be controlled at 30~50 ∕667 square meters.
(4) cultivation method. For floating plants such as water peanuts, water hyacinth and duckweed, bamboo poles and straw ropes can be used in the pond to cultivate them? D.C.? , intensive cultivation, so that the above aquatic plants in? D.C.? Grow and breed in the environment to supplement the shortage of aquatic plants in shrimp ponds.
(5) Sowing method. Generally, the most commonly used aquatic plants are Vallisneria angustifolia. Sophora alopecuroides adopts sowing method, which is suitable for shrimp ponds with less silt. First, soak the seeds of Sophora alopecuroides in water for 1 day, then crush the softened fruit to get tiny seeds in the fruit, add fine sand about 10 times the amount of seeds, mix well with the seeds and sow. When sowing, the water level is controlled at10 ~ 20cm, and the sowing amount is about 50g per 667m2. After sowing, management should be strengthened to improve the survival rate of Sophora alopecuroides and make it form a dominant population as soon as possible.
Aquatic plants needed to cultivate crayfish
First, Sophora alopecuroides
Sophora alopecuroides, commonly known as Hedyotis diffusa, is a perennial submerged plant, with leaves clustered at rhizome nodes and long green strips. It is 30-300 cm long, 4- 18 mm wide, bright green, with inconspicuous small serrations on the leaf edge. It grows in rivers and lakes and is a high-quality feed for crayfish. It grows with stolons and spreads tillers at the bottom of the water. After autumn, it forms a round bulb to overwinter and germinate into a plant in the next spring. The magnetic heterozygote of plants is a typical water-borne flower, which is pollinated by hydraulic power. Sexual reproduction plays an important role in life history, and its seeds are easy to collect, store and transport, and are easy to popularize. The seeds of Sophora alopecuroides are rhombic, and the seeds in the seed pods are dark brown and full. When sowing, firstly, soak the seeds of Sophora alopecuroides in water for 12-24 hours, rub out the tiny seeds in the seed pods, then add the fine sandy loam with the amount of 10 times, and mix with the seeds to sow. When sowing, the seeds should be spread evenly, and the amount of seeds used per mu of water surface is 70-100g. The seeds of Sophora alopecuroides germinate when the water temperature is above 15℃, and the germination rate is higher, generally above 90%. If sowing is too early, the water temperature is not high, which directly affects the germination rate; If sowing is too late, the seeds will be easily eaten by crayfish after germination, and it is difficult to form a colony. Therefore, it is more suitable to sow before and after Grain Rain.
Second, Potamogeton microphylla
Potamogeton microphylla is commonly known as yellow grass. The stems and leaves are slender and crisp, which is one of the favorite aquatic plants for crayfish. Potamogeton microphylla has strong water purification ability, strong vitality and strong adaptability, and is not suitable for being destroyed by lobsters. It can be widely planted in ponds, and sowing can begin when the water temperature rises above 10℃ in spring. POTAMOGETON microphylla seeds are large, with 500-800g seeds per mu. When sowing, the seeds need to be soaked in pool water or river water for 5-7 days to accelerate germination. Generally, they will germinate after sowing 10- 12 days. Before sowing, it is necessary to control the water level and maintain the maximum transparency of the pool water, which generally takes 35-40 cm.
Iii. hydrilla verticillata
Hydrilla verticillata, commonly known as needle grass, lantern grass, shrimp, etc., is a submerged plant for many years, with slender and cylindrical stems. 30-50 cm long, 2-2.5 mm in diameter, branched, impeller-shaped, sessile, usually 6, about 1.5 cm long and 0.3 cm wide, with fine serrations at the leaf edge, growing in lakes, ditches and slow-flowing water, and its stems and leaves are the best natural herbivores for crayfish. Sowing can be done when the water temperature rises above 15℃ every April. Before sowing, the seeds should be soaked in pool water or river water for 3-5 days, then the attached skins of the seeds should be washed away with clear water, and then a little pond mud and water should be added to mix well, and the seeds should be spread evenly in the whole pool, with the seed dosage per mu of150-250g. After sowing, it usually begins to germinate in about half a month under the condition of suitable water temperature. Reproductive growth is mainly asexual reproduction, which can grow into new plants independently from the mother, form winter buds in late autumn and grow into new plants in the following year. Dioecious, with small white flowers, but winter buds and seeds are not suitable for collection, so plant transplantation is generally the main method. The grass likes high temperature, has strong adaptability, long growth period and strong regeneration ability, and is suitable for planting in ditches, ponds and large water surfaces with sufficient sunlight. Since every branch of this grass cut off by lobsters can take root again, it is not advisable to sow too much to ensure that lobsters can be used.
Fourth, Ceratophyllum
Ceratophyllum is a submerged plant for many years. The plant body is smooth, the stem is slender and branched, which is fragile and easy to break. The leaves are linear,15-25mm long, mostly forked and split, with spiny fine serrations on the edge, usually 6-8 leaves are whorled and leafless, and grow in ponds, lakes, rivers and other waters, and their stems and leaves are popular with lobsters. Reproductive growth is asexual reproduction, which can grow into new plants from plant fragments and live independently from the mother. In late autumn, winter buds formed by dense stems and leaves sink to the bottom for wintering, and germinate into new plants the next year. The fruit is a small oval nut, but the seeds are not suitable for collection, so the general pond is mainly based on plant transplantation.
V. Eichhornia crassipes
Eichhornia crassipes is commonly known as water hyacinth. Perennial floating plant with tufted leaves, round or heart-shaped leaves and a diameter of 6- 12 mm. The leaf surface is smooth, the top is round or slightly protruding, the petiole 10-20 cm, the lower part of the petiole expands into a gourd-shaped floating sac, and the base has a transparent membranous sheath bract. Most of them grow in ponds and ditches, and reproduce by creeping stems, especially in fertile water, which has obvious effects of absorbing fertilizer and purifying water quality. Its fibrous roots are good feed for lobster seedlings and young shrimps, and are also ideal aquatic plants for cultivating shrimp seedlings. Transplanting is easy, just cover the small water body with plastic film when preserving seeds in artificial winter.
Vi. Potamogeton malayi
Potamogeton malayi is a perennial aquatic plant, most of which grows in water. The stem is cylindrical, 0.5-2m long and1.5-2.5mm in diameter, with a few branches. Most leaves are submerged leaves, thick film, 5- 10 cm long and 1-2 cm wide. Alternately, the lower leaves of the pedicel are opposite, the leaf margin is wavy and has irregular serrations, the petiole is 2-5cm long, and it grows in rivers, lakes or ditches with hard substrate, and some young stems and leaves can be eaten by lobsters. Reproduction is mainly asexual reproduction, winter buds are formed in late autumn and germinate in the next year. The inflorescence is spike-shaped, and the seeds are not easy to collect, so transplantation is generally the main method.
Seven, duckweed
There are many kinds of duckweed. First, duckweed, also known as sesame duckweed, has thin stems and tender leaves, which are grass green. The second is duckweed with dark green leaves and purple back, also known as purple duckweed and daping. Its growth temperature is 25-30℃, and its growth is affected in high temperature season. In late autumn, when the water temperature drops, the duckweed grows winter buds, sinks to the bottom of the water, and the mother dies. In the following spring, winter buds surfaced to germinate new individuals. The third is Sophora japonica, whose face is green and whose body is opposite. Fourth, Azolla, also known as Manjianghong, is green in spring, turns reddish brown in autumn, and spores in late autumn. Azolla likes warmth, and its optimum growth temperature is 20-25℃. When the temperature is above 30℃, its reproduction slows down and it stops growing at 5℃.
Duckweed is a good feed for crayfish after Wuping. Duckweed has strong flame resistance and can multiply in paddy fields and ditches. In the wet and rainy season, its reproduction is the most vigorous. Duckweed can be cultivated in pits and ditches with thick sediment. Before the end of March, the pond was cleared with quicklime, and then basal fertilizer was applied. In late April, seeds were put in Grain Rain, and 120-200 kg per mu was put in, and wheat straw braids were used for frame culture, especially in spring and autumn. After the pond is full of duckweed, it can be harvested every 2-3 days, and the duckweed fishing should not exceed 50% of the total. If the management is proper, you can fish ping 100- 130 kg per mu every day. When the pool water becomes clear and the duckweed takes root, it should be topdressing, and the number of topdressing should be more and less. Dig out the bottom mud every few days to make the nutrients in the pond dissolve in water, so that the duckweed can absorb them. When the weather is hot, you should sprinkle water on the flat surface in the morning and evening. Other duckweeds, such as red duckweed and Sophora japonica, are cultivated in the same way as duckweed.
Eight, Potamogeton crispus
Potamogeton crispus is also called spring grass and wheat cucumber. Submerged perennial plant with oblate stems, about 50 cm long. Ye Guang linear, 2-7 cm long and 4-8 mm wide. Leaves sessile, alternate, wavy, with small serrations. Most of them grow in still water ponds and ditches. Crayfish don't like eating this grass very much. However, its biggest feature is that plants gradually die in the late summer wheat and yellow season, and at the same time form winter buds, which germinate and grow in winter and form grass communities in spring, which complement the grass communities formed by most other aquatic plants in the water area in summer, which is beneficial to the growth of crayfish in spring, molting and hiding, and improving the survival rate. The winter buds formed in summer are easy to collect and can be used as grass seeds. After processing, they can be preserved. In winter, they can be mixed with soil and sprinkled in water, and an ideal aquatic plant can be formed in the Spring Festival.
Nine, Wuping
Wuping, also known as Weishan and rootless duckweed, is the smallest duckweed family. Wuping is about 1 mm long, rootless and stemless, and it is an oval granular body. It reproduces with spores, rises to the surface in warm weather and sinks to the bottom of the pond in cold weather, so it is a good feed for crayfish.
Culture technology of crayfish
Seedling cultivation
The cultivation pond is mainly a cement pond with an area of 20-40 square meters and a water depth of 0.6-0.8 meters. You can also choose a pond with good water quality near the water source and build drainage and escape prevention facilities. Before releasing seedlings, the pond is strictly disinfected, and basic fertilizer is applied to cultivate plankton to provide open bait. The area of transplanted aquatic plants accounts for 30% of the water surface. Put 0.8 cm juvenile shrimp10-150,000 per mu. At the early stage, natural bait was mainly used, and soybean milk and minced fish were properly fed. With the growth of individuals, artificial feed was mainly used.
pond culture
Put young shrimp 1- 1.5 million per mu, sprinkle quicklime regularly to increase the calcium content in the water, and increase the amount of feed at night, mainly with compound feed.
daotianyangzhi
Choose a field with good water quality, no pollution sources around, strong water-retaining ability, convenient irrigation and drainage, and no flooding to raise shrimp in the rice field. Dig a shrimp-raising ditch along the inside of the rice field ridge, with a width of 1.5 m and a depth of 1 m. If the field area is large, dig a field ditch in the middle of the field with a width of/kloc. The ridge width is more than 3 meters, and the ridge height is 1 meter. At the place away from the ridge 1 m, a pile with the height of 1.5 m should be drilled every 3 meters, erected with bamboo, and melons, beans, gourds, etc. should be planted at the edge of the ridge. After the vines are put on the shelf, it will play a role in shading and summer in hot summer. Water plants, such as submerged plants such as Sophora alopecuroides, Haematococcus verticillata and Ceratophyllum, should be transplanted in shrimp ditches and fields, and the coverage of water plants should be 30%, and it is better to be scattered and scattered, which is beneficial to the smooth flow of water in shrimp ditches. An escape wall is built around the field with plastic film, cement board, asbestos tile or calcium plastic board to prevent crayfish from escaping.
Seedling stocking
Crayfish should be stocked with water, and shrimp can only be released after the water is tested safely. There are two ways to raise crayfish: first, put the shrimps directly into the rice field in the first ten days of September after the rice is harvested, and let them breed by themselves. According to the actual situation of rice field culture, generally, 20 kilograms of crayfish with individuals of more than 40 grams per acre are raised, and the sex ratio is 3:1. Second, after rice seedlings are planted in May, young shrimps with the size of 2-4cm 1500-2000 or 30kg/mu are put in. When stocking crayfish, attention should be paid to the quality of young shrimps, and the stocking specifications of the same field should be as neat as possible, and they should be fully stocked at one time. Stocking in sunny morning or rainy day, and disinfecting with 3% ~ 4% salt water bath 10 minute when stocking young shrimp.
Suitable area
Ponds, low-lying areas, rivers and rice fields can be cultivated.
See what aquatic plants crawfish eat and see:
1. Classic advertising words of lobster brand
2. The best lobster restaurant in Wuhan
3. guess the lobster riddle
4. Creative crayfish advertising language
5. Creative crayfish advertising words