Crayfish technology, crayfish seedling technology

You can go to a formal school to learn food, and the taste is more authentic.

What is there not to understand brother? I also started farming last year. I can give you some advice.

Although the number of lobsters holding eggs is not large, the fertilization rate can be more than 98%, and the hatching rate can reach 80%-85%. The problem is that the larvae grow and molt frequently after emergence, and the seedling rate is easily affected by environmental conditions. What can be done to increase the seedling rate?

Let me take you to learn more about it.

Although the number of lobsters holding eggs is not large, the fertilization rate can be more than 98%, and the hatching rate can reach 80%-85%. The problem is that the larvae grow and molt frequently after emergence, and the seedling rate is easily affected by environmental conditions. In order to improve the seedling rate, the key is to do the following:

1. Water quality requirements.

During the lobster breeding period, the water body should be kept relatively stable, the water quality is fresh, and the pH value is in between; Prevent excessive temperature difference between day and night; Dissolved oxygen in water should be kept above milligrams.

2. Water environment.

There must be water floating lotus (accounting for 1 3) on the water surface, and there are best aquatic plants at the bottom of the water, and there are hidden caves, so as to increase the molting and attachment of shrimp seedlings, and it is also convenient to grasp the seedling emergence time and the growth of shrimp through the washing of water floating lotus seedlings. The water inlet is fenced and filtered to prevent predators from entering the pond, and at the same time prevent frogs from entering the pond to lay eggs, and to prevent tadpoles from eating shrimp seedlings. At the same time, it is necessary to prevent broodstock from climbing and escaping.

3. Strengthen inspections.

Insist on checking the emergence of seedlings in the morning and evening, when the larvae are free from the mother, catch the broodstock in time and return to the broodstock pond for re-cultivation, minimize the inventory of the pond, and the operation should also be particularly careful to avoid the impact on the broodstock holding eggs and the newly hatched larvae.

4. Ensure feeding.

Cultivate small zooplankton such as rotifers in a timely manner for the newly hatched larvae to feed, and it is estimated that 3-5 days before emergence, a small number of small zooplankton will be harvested from the feed pond into the shrimp seedling pond. And use cooked egg yolk, soybean milk, etc. to supplement the food required for juvenile and juvenile shrimp in a timely manner**.

1. Seedling environment.

The deterioration of the environment and the substandard water quality have led to the slow growth of shrimp seedlings, the decline of physical fitness, and the enrichment of toxins in the body.

2. Inbreeding.

Inbreeding leads to germplasm degradation.

3. Feed nutrition is incomplete.

As a result, the shrimp seedlings grow slowly, the head is large and the tail is small, and the physique declines.

4. The density of seedlings is too large.

As a result, the crayfish has uneven physical specifications and is not strong.

5. Fishery medicine or pesticides.

As a result, drug residues exceed the standard, affecting food safety.

1. Look at the ability to move.

Catch the shrimp fry and put them in the container, the shrimp fry that are alive and kick around are good, and the shrimp fry that are slow are bad.

2. Look at the body color.

Good crayfish seedlings have bright and shiny body colors, and the group pigment is the same; Poor crayfish fry tend to have a dull body color and different group pigments.

3. Look at the composition of the group.

Good shrimp seedlings are neatly sized, the body is robust, the body surface is smooth without mud, and the swimming is lively; The poor shrimp seedlings are uneven in size, the individuals are thin, and some of them are stained with sludge.

Lobster breeding technology training includes: seedling density, pond disinfection, shrimp seedling selection, aquatic weed planting, feeding principles, and disease control.

1. Seedling density

Lobster farming no matter which breeding mode, the stocking density must not be too high. Even the intensive culture density in Tangkou should be controlled at 80 to 100 catties per mu, and the density of polyculture mode should be reduced to 50 to 60 catties per mu.

Excessive seed stocking density will bring great pressure to the pond environment and management. It is easy to cause the size of lobster to be small, and shrimp is easy to die due to lack of bait, poor breeding environment, lack of oxygen and other factors.

2. Disinfection of clear ponds

Pond cleaning and disinfection can effectively kill predators in the pond, such as catfish, black fish, snakes, rats, etc., wild miscellaneous fish that compete for food, such as carp, crucian carp, etc., as well as pathogenic bacteria. The commonly used methods are quicklime disinfection, and quicklime has two types: dry disinfection and water disinfection.

Dry disinfection method: 50 to 100kg of quicklime per mu, splash the whole pond, and then pour new water after 3 to 5 days of drying the pond. Water disinfection method: each mu of water surface is calculated with a water depth of 1 meter, and 125 to 150kg of quicklime is dissolved in water, and the whole pool is evenly sprinkled.

3. Selection of shrimp seedlings

Choose shrimp seedlings with neat stocking specifications, strong physique, complete appendages, clean body surface, no injury and disease, and strong mobility, and local high-quality shrimp seedlings are the best.

4. Aquatic weed planting

Aquatic plants are natural bait for lobsters, providing lobsters with a place to perch, molt, shade and avoid enemies, and can also improve the dissolved oxygen of the water body, cool down, regulate and purify water quality, and improve the substrate.

At present, the common varieties of aquatic plants are Elophylla, Melanophyllum rotiflora, Fishfish algae, Vulgaris, Millet grass, Peanut and so on.

5. The principle of feeding

Feed feeding adheres to the principle of "five determinations", and adjusts according to the season, weather, water quality and shrimp activities, and sets up a food table to observe the lobster feeding.

Lobsters have a more mixed diet, and feed on rotifers, cladopods, copepods or aquatic animal larvae in the pond in the early stage of seedling, and cooperate with artificial feeding of minced small trash fish and minced meat.

In the middle and later stages, animal feeds such as small trash fish, artificial compound feed, and plant feed are fed.

6. Prevention and control of diseases

Regularly sterilize and disinfect the water body, and splash it with 10 to 15kg of quicklime slurry every 667 square meters every 10 to 20 days. Diagnose sick shrimp in time, use drugs that meet the national fishery medicine standards**, and do not use drugs blindly.

<> crayfish are red or dark red in their entirety, 20 knots. Among them, the cephalothorax is cylindrical, with 13 segments (5 segments of the head and 8 segments of the thorax), with a triangular frontal angle and 3 pairs of tentacles at the front end, and a total of 5 pairs of thorax and feet. There are 7 segments in the abdomen, 6 pairs of appendages, and the tail fan is formed by the flattened tail segment at the last end and the appendage of the 6th abdominal segment.

First, the appearance characteristics

1. The body length of the crayfish is about, the body color is red, reddish-brown or dark red (light brown and yellow-brown when immature), the breastplate is pink on both sides, with orange or white spots, a total of 20 segments, except for the tail segment without appendages, the rest of the segments have appendages.

2. Cephalothorax: The crayfish cephalothorax is cylindrical, with a total of 5 segments of the head and 8 segments of the chest. The anterior end has a triangular frontal angle, the middle of the surface is concave, there are ridges on both sides, and the tip is sharply spine-like, with a total of 3 pairs of tentacles (the pair of tentacles on the outer edge of the head is particularly thick and long, about one-third longer than the body length).

The dorsal surface of the cephalothorax is connected to the chest wall, and the two sides are free to form the gill cavity. There is a curved cervical groove between the head and neck. There are 5 pairs of thoracic feet, all of which are single-branched, of which the first pair is chelica-shaped, strong and thick, the 2nd-3rd pair is pincer-shaped, and the 4th-5th pair is claw-shaped.

3. Abdomen and tail: There are 7 segments in the abdomen, 6 pairs of appendages, and the last end has a flat tail segment and the 6th abdominal segment appendage to form a tail fan (a total of 5 pieces). Among them, the first pair of gastropods of female crayfish degenerated, and the first and second pairs of gastropods of male crayfish evolved into calcium transfer organs.

Second, the characteristics of the living environment

1. Habitat: Crayfish mainly inhabit rice fields, ditches, rivers, streams, lakes, ponds, reservoirs, swamps and other places.

2. Temperature: The temperature range of crayfish is relatively wide, but when the temperature is too high or too low, it will affect its growth and development, and the water temperature is generally about 22-30.

3. Dissolved oxygen: crayfish has strong ability to tolerate hypoxia, and the dissolved oxygen content of the water body can meet the normal growth and development of crayfish when the dissolved oxygen content is more than 3-4mg l.

4. Water pH: Crayfish like neutral or slightly alkaline water, and it is more appropriate to have about pH of the water body.

5. Light conditions: Crayfish like low-light environment or dark environment, when the light is too strong, crayfish hide in burrows or under aquatic plants and branches.

The breeding technology of crayfish must be high, and crayfish has strong adaptability to the environment, and can grow in various water bodies such as lakes, ponds, ditches, and rice fields. The water source should be sufficient, and the water depth should be about 1 meter.

The pond must have sufficient water source, good water quality, convenient water intake and drainage, and the area is generally 3 acres and 5 acres. The ridge of the pond should have a certain slope, and in order to avoid the escape of crayfish burrowing, the width of the ridge should be above the meter, and the anti-escape wall or anti-wisdom escape board with high and smooth inner wall should be set around the ridge. Some mud mounds were built in the middle of the pond to provide a place for crayfish to burrow.

The water depth of the pond is suitable for meters, preferably the middle water depth, there are shallows around it, and tree roots, bamboo tubes, etc. are placed at the bottom of the pool. Strict disinfection before stocking, 300 500 kg of rotted livestock and poultry manure per mu. Aquatic plants accounting for 30% of the pond area are planted in the pond, such as bitter grass, black algae, water hyacinth, water floating lotus, water peanut, etc., which are convenient for crayfish to avoid enemy invasion and inhabit when molting.

Management methods

Insist on patrolling the pond every day, and deal with problems in a timely manner. Timely top dressing, shrimp seedlings stocking 1 week, 50 kg of rotten livestock and poultry manure per mu 60 kg, in the middle and late stages of breeding, every half month per mu of fermented manure 15 kg 20 kg, keep the pond water bean green or brown, transparency in about 35 cm. Frequently inject new water, change the water every 5 days and 7 days in the high temperature season, change the water every 15 days and 20 days, and change the water every 20% 30% of the pool water each time, and keep the pH value of the pool water between 7 and 9.

Regularly disinfect and improve the water body, splash the whole pool with 10 kg of quicklime and 15 kg of chemical water every 15 days per mu, and splash the whole pool with grams of bleaching powder per cubic meter of water every month. In the middle and late stages of aquaculture, 5 grams and 6 grams of photosynthetic bacteria, 40 grams and 60 grams of dust mold substrate improver are used to splash the whole pool of water per cubic meter of water every month to maintain a good water environment.

Prepare the pond: build the pond in a place with ventilation and sunshine, quiet environment, and convenient drainage and irrigation, with no silt at the bottom of the pond and a certain slope of the pond wall. Shrimp seed stocking:

It is advisable to have 10,000-20,000 tails per mu. Regular feeding: Feed trash fish, snail mussel meat, bean cake, etc. 1-2 times a day.

Regular pond patrols: Drain the water during the rainy season to prevent crayfish from escaping.

1. Prepare the pond

The pond for breeding crayfish should be selected in a place where ventilation is sunny, the environment is quiet, the drainage and irrigation are convenient, and the water quality is pollution-free, the pond should be rectangular, the water depth is about meters, the bottom of the pond is hard soil or sandy, no silt, and the pond wall must have a certain slope to avoid the shrimp seedlings escaping.

2. Shrimp seed stocking

Juvenile shrimp require strong physique, complete appendages, no injury or disease, strong mobility, and the same pond stocking specifications should be consistent, with 10,000-20,000 per mu is appropriate, before stocking crayfish, first put the juvenile shrimp into a plastic basin, soak in 3%-4% salt water for 5 minutes, and then slowly put into the pool along the edge of the pool.

3. Feed regularly

Pond crayfish can be directly fed with minced trash fish, snail mussel meat, silkworm pupa, earthworms, etc., or provide rice bran, bean cake, bran, pumpkin, yam and fresh aquatic plants, etc., to keep the crude protein content of the feed at more than 25%, and feed 1-2 times a day.

4. Patrol the pond regularly

When breeding crayfish daily, we must regularly patrol the pond, especially when it rains, the water level is **, the lobster is likely to escape, and it is necessary to strengthen the fence and iron net in time to prevent losses, and adjust the water quality according to the situation of the shrimp group, and replace the fresh water.