What aquatic plants do crayfish eat: Crayfish actually eat this

Crayfish is something people like to eat, but many people are curious about what crayfish eat to grow up. People who raise crayfish can plant aquatic plants such as Hydrilla verticillata, Elodea, water peanut, water duckweed, etc. as food for crayfish. Let’s take a look with me below.

Water plants that crayfish eat

Crayfish are omnivorous animals that prefer animal food. They like to eat animal food such as fresh fish, earthworms, snails and mussels, and livestock and poultry offal. Cats like to eat plant-based feeds such as soybeans, bean cakes, bran, corn, and fresh aquatic plants. They can also be fed shrimp compound feeds, but their feeding habits vary slightly at different stages of development.

In the natural environment, the newly hatched larvae of crayfish use their own yolk as nutrition. Soon after, they feed on small zooplankton such as rotifers. As the individuals continue to grow, they feed on larger plankton. Animals, benthic animals and plant detritus. Adult shrimps eat both animals and plants. They mainly eat plant detritus and animal carcasses. They also eat water earthworms, chironomid larvae, small crustaceans and some aquatic insects.

In an artificial breeding environment, crayfish juvenile and juvenile stages feed on rotifers, cladocerans, copepods, and aquatic insect larvae, while the adult shrimp stage also eats animal feed. , plant feed. During the rapid growth stage of crayfish from August to October, feed more bran, bean cakes and green feed, and appropriately feed animal feed. From November to December, crayfish are mainly fed animal feed before overwintering.

Therefore, under natural conditions, crayfish will eat grass, such as phytoplankton and young parts of aquatic plants; in artificial breeding, the food can be adjusted according to the feeding characteristics of crayfish, so that crayfish Grows fast.

Planting aquatic plants in crayfish breeding ponds

(1) Planting method. Hydrilla verticillata, Elodea and other stemmed aquatic plants are suitable for transplanting, and are generally planted in winter and spring. The method is to cut the aquatic plants into small sections, with a length of 15 to 20 centimeters. Just like transplanting rice seedlings, insert the bunches of cut grass sections evenly into the mud at the bottom of the pond, and control the plant and row spacing at about 20 centimeters respectively. After transplanting, add 20 to 30 centimeters of water to the shrimp pond, and gradually deepen the water level after the aquatic plants have filled the entire pond.

(2) Throwing method. Floating-leaf plants such as water chestnuts and water lilies can be packed tightly with soft mud and then thrown directly into the pond, so that their roots can grow in the bottom mud and their leaves can float on the water.

(3) Transplanting method. Emergent plants such as wild rice and sagittaria should be transplanted uprooted. When transplanting, damaged leaves and slender and inferior seedlings should be removed. The transplanting location can be in the shallows beside the pool. The water required for the roots of the seedlings is between 10 and 20 centimeters. The density can be controlled to 30~50 trees/667 square meters.

(4) Cultivation method. For floating plants such as water peanuts, water hyacinths, and duckweeds, you can use bamboo poles, straw ropes, etc. to separate a corner in the pond as a "special zone" for intensive cultivation, so that the above-mentioned aquatic plants can grow and reproduce in the "special zone" environment. Used as a supplement when there is insufficient water and grass in the shrimp pond.

(5) Sowing method. Generally the most commonly used aquatic plant is Vallisneria vulgaris. Vallisneria adopts sowing method, which is suitable for shrimp ponds with less silt. First, soak the Vallisneria seeds in water for 1 day, then crush the soaked fruits, rub out the tiny seeds in the fruits, add about 10 times the amount of fine sand and soil to the seeds, mix well with the seeds and then sow. When sowing, control the water level at 10 to 20 cm, and the seeding rate is about 50 grams per 667 square meters. After sowing, management must be strengthened to improve the survival rate of Vallisneria so that it can form a dominant population as soon as possible.

Aquatic plants needed to grow crayfish

1. Vallisneria

Vallisneria, commonly known as pole grass and duckweed, is a perennial submerged plant with leaves in The rhizomes are clustered at the nodes and have long green ribbons. 30-300 cm long, 4-18 mm wide, bright green, with inconspicuous small serrations on the leaf edges. 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, They form round bulbs that survive the winter and sprout into plants the following spring.

The plant is magnetically dioecious, and pollination is carried out with the help of water power. It is a typical water-borne flower. Sexual reproduction plays an important role in the life history. Its seeds are easy to collect, store and transport, and are easy to promote. The seeds of Vallisneria vulgaris are long rhombus-shaped, the seeds inside the seed pods are dark brown, and the seeds are plump. When sowing, first soak the Vallisneria seeds in water for 12-24 hours, rub out the tiny seeds from the seed pods, then add 10 times the amount of fine sandy loam, mix well with the seeds, and then sow. When sowing, spread the seeds evenly and use 70-100 grams of seeds per acre of water surface. Vallisneria seeds germinate when the water temperature is above 15°C, and the germination rate is high, generally above 90°C. If sown too early, the water temperature will not be high, which will directly affect the germination rate; if sown too late, the seeds will be easily eaten by crayfish after they germinate, making it difficult to form clusters. Therefore, it is more appropriate to sow seeds before and after Grain Rain.

2. Microtoothed Echinacea

Microtoothed Echinacea is commonly known as yellow grass. The stems and leaves are slender and crisp, which is one of the aquatic plants that crayfish like to eat. Echinacea has strong water purification ability, strong vitality and strong adaptability. It is not suitable to be destroyed by lobsters. It can be widely planted in ponds. Sowing can be started when the water temperature rises above 10℃ in spring. The seed grains of Microtetragonata are larger, and 500-800 grams per acre are used. When sowing, the seeds need to be soaked in pool or river water for 5-7 days for germination. Generally, they will germinate in 10-12 days after sowing. Before sowing, the water level must be controlled and the pool water must have maximum transparency, which generally requires 35-40 cm.

3. Hydrilla verticillata

Hydrilla verticillata, commonly known as needle grass, lantern grass, shrimpweed, etc., is a perennial submerged plant with slender, cylindrical stems. 30-50 cm long, 2-2.5 mm in diameter, branched, whorled, sessile, usually 6 pieces, about 1.5 cm long, 0.3 cm wide, with finely serrated leaf margins, growing in lakes, ditches and streams In slow flowing water, its stems and leaves are the best natural food for crayfish. Sowing can be done in April every year when the water temperature rises above 15°C. Before sowing, the seeds should be soaked in pond or river water for 3-5 days, and then washed with clean water to remove the attached outer skin of the seed grains. Add a little pond mud and water and mix well. Spread the seeds evenly throughout the pond, using 150-250 grams of seed per acre. After sowing, germination usually begins in about half a month under conditions of suitable water temperature. Reproduction and growth are mainly asexual reproduction. Plant fragments can separate from the mother body and grow into new plants independently. Winter buds are formed in late autumn to overwinter and grow into new plants the following year. It is dioecious and has small white flowers. However, it is not suitable to collect winter buds and seeds, so the plants are generally transplanted. The grass likes high temperatures, has strong adaptability, a long growth period and strong regeneration ability. It 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 re-enter the soil and take root, it is not advisable to sow too much to ensure that the lobsters can use it.

IV. Hornwort

Hornwort is a perennial submerged plant. The plant body is smooth, the stems are slender and branched, relatively fragile and easy to break. The leaves are linear, 15-25 mm long, mostly fork-shaped splits, with spiny fine serrations on the edges, usually in whorls of 6-8 leaves, without petioles, growing in various waters such as ponds, lakes, rivers, etc., and their stems and leaves are Lobsters love to eat. Reproduction and growth are asexual reproduction. Plant fragments can live independently from the mother body and grow into new plants. In late autumn, the stems and leaves are densely formed and winter buds sink to the bottom of the water to overwinter and sprout into new plants the following year. The fruits are small long oval nuts, but the seeds are not suitable for collection, so the plants are generally transplanted into ponds.

5. Eichhornia crassipes

Eichhornia crassipes is commonly known as water hyacinth. Perennial floating plant with clustered leaves, round or heart-shaped leaves, 6-12 mm in diameter. The leaf surface is smooth, the top is rounded or slightly protruding, the petiole is 10-20 cm, the middle part of the petiole is enlarged into a gourd-shaped floating sac, and the base has a transparent membranous sheath-like bract. It mostly grows in ponds and ditches. It reproduces by stolons during reproduction. It reproduces very quickly especially in fertilized water. It has obvious effects of absorbing fertilizer and purifying water quality. Its fibrous roots are good feed for lobster seedlings and juvenile shrimps, and are also suitable for cultivating shrimps. Ideal aquatic plant for seedlings. Transplanting is easy, just cover the small water body with plastic film during artificial winter conservation.

6. Echinacea

Echinacea is a perennial aquatic plant, most of which grows in water.

The stem is cylindrical, 0.5-2 meters long, 1.5-2.5 mm in diameter, with a few branches. The leaves are mostly submerged leaves, thickly membranous, 5-10 cm long and 1-2 cm wide. They are alternate, with opposite lower leaves on the pedicel. The leaf margins are wavy and irregularly serrated. The petioles are 2-5cm long. They grow in rivers, lakes or ditches with hard substrates. Some of the young stems and leaves can be eaten by lobsters. Reproduction is mainly asexual. Winter buds are formed in late autumn to survive the winter and germinate in the second year. The inflorescences are spike-shaped and the seeds are difficult to collect, so they are usually transplanted.

7. Duckweed

There are many kinds of duckweed. One is small duckweed, also known as sesame duckweed, with thin stems and tender leaves, which is grass green. The second is the purple-backed duckweed, which has dark green leaves and purple undersides. It is also called purple duckweed and duckweed. Its suitable growth temperature is 25-30°C, and its growth is affected in high-temperature seasons. In late autumn, when the water temperature drops, winter buds grow from the duckweed body and sink to the bottom of the water, and the mother body dies. The following spring, new individuals sprout from the winter buds that surface on the surface. The third one is Sophora japonica, with green surface and opposite body. The fourth is Azolla, also known as Azolla, which is green in spring, turns reddish brown in autumn, and forms spores in late autumn. Azolla likes warmth, and its suitable growth temperature is 20-25°C. Reproduction slows down above 30°C, and growth stops at 5°C.

Duckweed is a good feed for crayfish after turnip. Duckweed has strong flame resistance and can reproduce in large numbers in paddy fields and ditches. It breeds most vigorously in warm, humid and rainy seasons. Duckweed can be cultivated in pits and ditches with thick mud. Before the end of March, use quicklime to clean the pond and then apply basal fertilizer. Plant seeds in late April during the grain rain period. Put 120-200 kilograms per acre. Use wheat straw braids to cultivate in compartments. Reproduction is particularly rapid in spring and autumn. After the pond is full of duckweed, it can be harvested every 2-3 days, and the amount of duckweed harvested each time should not exceed 50% of the total amount. If managed properly, 100-130 kilograms of duckweed can be harvested per acre per day. When the water in the pool becomes clear and the epipods take root, top dressing should be applied. The frequency of top dressing should be more, but the quantity can be smaller. Dig out the bottom mud every few days to dissolve the pond nutrients in the water for absorption by the duckweed bodies. When the weather is hot, water should be sprinkled on Pingmian in the morning and evening. The cultivation methods of other duckweeds, such as red duckweed and duckweed, are the same as duckweed.

8. Sedge

Sedge is also called spring grass and wheat cucumber. Perennial submersed plant with oblate stems, about 50 cm long. Leaves are broadly linear, 2-7 cm long and 4-8 mm wide. The leaves are sessile, alternate, with wavy margins and small serrations. It mostly grows in still water ponds and ditches. Crayfish do not like to eat this grass. But its biggest feature is that plants gradually die during the wheat yellowing season in late summer, and winter buds are formed at the same time. They sprout and grow in winter, and grass communities are formed in spring. Most of the other aquatic plants in the water form grass communities in summer, forming a complementary effect, which is beneficial to crayfish in spring. Growth, molting, hiding, and improving survival rate. The winter buds formed in summer are easy to collect and can be used as grass seeds. They can be stored after processing. In winter, they can be mixed with soil and sprinkled into water. During the Spring Festival, ideal aquatic plants can be formed.

9. Lemna

Lemna is also called Weisha and Rootweed. It is the smallest species in the duckweed family. The body of turnip is about 1 mm long, without roots or stems. It is an oval granular body that reproduces with spores. It surfaces when the weather is warm and sinks to the bottom of the pond when the weather is cold. It is a good feed for crayfish.

Crayfish culture technology

Seed cultivation

The cultivation pool area is 20-40 square meters, and the water depth is 0.6-0.8 meters, mainly cement pools. You can choose a pond with better water quality near the water source and build drainage and escape prevention facilities. The pond should be strictly disinfected before the seedlings are released, base fertilizer should be applied to cultivate plankton to provide open feed, and the area of ??transplanted aquatic plants should account for 30% of the water surface. 100,000 to 150,000 0.8 cm juvenile shrimps are released per acre. In the early stage, natural feed is mainly used, and soy milk and surimi are appropriately fed. As the individuals increase, artificial feed is mainly used.

Pond culture

Put 10,000 to 15,000 juvenile shrimps per acre, regularly sprinkle quicklime to increase the calcium content in the water, and increase the amount of feed at night, mainly compound feed.

Rice field farming

Select fields with good water quality, no pollution sources around, strong water retention capacity, convenient drainage and irrigation, and are not flooded for rice field shrimp farming. Dig a trench for shrimp farming, with a trench width of 1.5 meters and a depth of 1 meter. If the field area is large, a field trench must be dug in the middle of the field. The field trench is 1 meter wide and 0.5 meters deep. The shrimp farming trench and field ditch The area accounts for about 20% of the total rice field area. The width of the field ridge is more than 3 meters, and the height of the field ridge is 1 meter. Drill 1.5-meter-high piles 1 meter away from the field ridge every 3 meters and set them up with moso bamboo. Plant melons, beans, gourds, etc. on the side of the field ridge. After the vines are put on the shelves, they will provide shade and avoid the heat in the hot summer. effect. In shrimp farming ditches and fields, aquatic plants should be transplanted, such as Vallisneria verticillata, Hydrilla verticillata, Hornwort and other submerged plants. The coverage area of ??aquatic plants should be 30%, and it is better to be sporadic and scattered. This will help the water flow in the shrimp ditch unimpeded. plug. Use plastic film, cement board, asbestos tile or calcium plastic board to build anti-escape walls around the field to prevent crayfish from escaping.

Seed stocking

When stocking crayfish, the water must be tested. Only when the water is safe can shrimp be released. There are two methods of stocking crayfish: one is to put the brood shrimp directly into the rice field in early September after the rice harvest and let them reproduce on their own. According to the actual situation of rice field breeding, generally more than 40 grams/crayfish are stocked per acre. The crayfish weighs 20 kilograms, and the male to female ratio is 3:1. Second, after the rice is planted in May, 1,500-2,000 juvenile shrimps with a size of 2-4 cm/acre or 30 kg/acre are released. When stocking crayfish, attention should be paid to the quality of the young shrimps. The stocking specifications in the same field should be as neat as possible, and enough should be stocked at one time. Stock the shrimps in the morning on a sunny day or on a rainy day. When stocking the young shrimps, wash them in a 3-4 degree salt water bath for 10 minutes for disinfection.

Suitable areas

Ponds, low-lying lands, rivers and rice fields can be cultured.

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