Restocking of broodstock
The initial pool holds 70 pounds per acre and the first paddy field has 40 pounds. The ponds cultivated for many years only need to be replanted. Generally, about 20 pounds per acre will be replanted. Generally, they will be carried out from August to the end of September each year. The physical fitness and meat fertilizer should be selected. Full-fledged, consistent specifications of broodstock and broodstock broodstock stocking.
10 days prior to stocking in paddy-free paddy fields, first use limed dry ponds to sterilize them, filter them after disinfection (to prevent wild fish ponds), and then inject new water into the ponds to keep the water depth of the ponds around 1 meter or so, in accordance with the area per acre. Apply appropriate amount of decomposed livestock manure to fertilize water. If it is to directly let broodstock hatch in the water and continue to raise larvae, and then directly develop prawn, you can put 50 pounds of broodstock per mu, and the proportion of female and male broodstock is 2:1 or 3:1, before stocking. Bathe in salt water for 5 minutes to kill pathogens on broodstock. If large numbers of seedlings are cultivated, 100 kg of broodstock can be stocked in an area of ​​one acre, and the proportion of female and male broodstock is 2:1.
Starting in early October, lower the water level to reveal dikes and high slopes to ensure that dikes and high slopes are separated by about 30 cm from the water surface, and that the depth of ponds or paddy field ditch must be maintained at 60 cm to 70 cm, allowing crayfish to hatch Reproduction. After the crayfish cave is basically dug, the water level is raised to about 1 meter.
Spawning type and hatching shrimp
There is controversy about the spawning type of crayfish, and there are two views to sum up: One view is that crayfish spawn three to four times a year; the other view is that one oviposition a year. Most people think that the spawning type of crayfish belongs to one year of spawning, which belongs to the autumn and winter breeding types, but the mating time for group mating is very long, from late April to the end of August. The peak period of mating and spawning is May to June. The fertilized eggs hatch in the abdomen of females as juvenile shrimp. The hatching time needs 40 days to 70 days. The suitable incubation temperature is 22°C to 28°C. Up to 200 or so. It can be self-produced, self-educated and self-supported without the need for complicated propagation and nursery equipment.
After hatching, the juvenile shrimps were all attached to the maternal abdomen and the growth of the larval stage was completed under the maternal protection. After hatching from the first autumn of juvenile shrimp, the growth, development, and wintering of the larvae are all attached to the maternal abdomen and leave the mother's life until the second spring. The amount of eggs held by the crayfish varies depending on the individual size of the broodstock. Individuals hold large amounts of eggs and small individuals hold little eggs, ranging from 500 to 1,000 grains. After hatching, the eggs develop into juvenile shrimp. One broodstock eventually has 100 to 300 tails.
It has been found that the crayfish that are broached in the hole are all male and female, and the female gonads are very mature. The gonads are found in the hole and the egg-bearing shrimp and the produced shrimp are found in the hole. In the cement holding pool, only the egg-holding shrimp was found and no shrimp seedlings were found. The holding eggs of the holding-bearing shrimps were very long and existed from the beginning of September to the end of November. Based on this, it is believed that: After the females open a hole during reproduction, the males reenter; the breeding takes place inside the cave and the inside of the cave reproduces earlier; the crayfish can also reproduce in the concrete pool, but the propagation period is delayed and an adaptation process is needed; The eggs held by a few egg-holding shrimps in the cement pool are unfertilized eggs. It can be inferred that the crayfish can be excreted in vitro without undergoing spermatization; the population is internally regulated and the population is regulated when the density is high.
Broiler breeding management
Feeding management of broodstock is relatively simple, and can be fed chopped snail meat, small fish, shrimp, slaughtered livestock and poultry, fresh water grass, bean cake, wheat bran or compound feed. Because the food intake of broodstock is more difficult to control, the daily feed volume is mainly due to changes in water temperature. Each day feeds once in the morning and in the evening, and is mainly in the evening. The specific feeding amount can be tested by trial and error. To determine whether the food that was fed the day before the next day is to see if there is surplus, if there is residual bait there is less investment, if there is no residual bait, it is appropriate to vote more, and less to vote after the fishing operation.
The management of water quality in broodstock ponds is very important. The first is to provide fresh water, the second is to provide exogenous microorganisms and minerals, and the third is to change the water every 2 weeks, changing the water every time; Lime splashed with water once to maintain good water quality and promote gonad development of broodstock.
Cultivation of pond shrimp
The hatched juveniles can quickly start eating, and feeds can be fed at this time. The feed is mainly natural zooplankton and artificial feed. Natural zooplankton mainly adopts organic fertilizer to fertilize water bodies and reproduce phytoplankton as bait for rotifers, small horned horns, and copepods. The artificial feed is mainly soybean cake, wheat bran and pellet feed, etc., and is fed twice a day. ~4 times, the feeding amount should be determined according to the juvenile activity, feeding and development.
During the nursing of young broodstock, shrimp should be properly fed, and more water should be changed to maintain a good water environment. In order to ensure that juvenile shrimp are not disturbed during clam shelling, and to prevent soft shell clams from being invaded, it is best not to have other fish in the broodstock culturing water during the breeding period; there must be a certain amount of plants in the breeding process, It is necessary to regularly check the water quality and make a good record of production so that lessons can be summarized.
Rice field and pond breeding crayfish
Breeding crayfish seedlings in paddy fields is low cost and operability. It is the most economical and best way to solve the source of crayfish seedlings.
With crayfish brooding one after another, most of the female crayfish that emerged from the hole were crustaceans. There were also early hatching and hatched larvae that had left the mother to live independently. There were also some prawn which only moved around the mother. When being frightened, it will be adsorbed on the mother. At this time, all the activities of the prawn are weak. If you do not get sufficient, palatable, nutritious food in time, it will affect the clams of the prawn, and may even be due to nutritional deficiencies. This resulted in the death of a large number of prawns. Therefore, the management work at this time is particularly important.
When the broodstock is found out of the hole (the hole has fresh mud that the broodstock began to hole), must be appropriate to add some fresh water or replace a portion of water, add water or change the water control in about 10 cm, the best conditions to maintain a micro Flowing water to ensure that the dissolved oxygen in the water can ensure the normal growth of the shrimp. At the same time, in order to ensure timely access to adequate, palatable, nutritious natural food after leaving the mother's body, the shrimp must be topdressed appropriately, using a Quanchiposa method to cultivate nutritious plankton and other natural foods. Feeding.
As the larvae continue to leave the mother's independent life, the number is increasing, and natural foods are far from satisfying their growth needs both in terms of quantity and nutrition. In order to ensure the nutritional needs of the growth of large-scale prawns, it is necessary to invest in artificial animal feeds with high nutritional value, such as fish gills. The fish is beaten into fish gizzards or fish paste and splashed around the pool. Daily Feeding 2 times in the morning, once in the morning, the feeding amount accounts for about 40% of the total feeding amount, and once in the evening, the feeding amount accounts for about 60% of the total amount of daily feeding.
At this time, the broodstock is still in the pool, in order to prevent competition, a certain amount of broodstock feed must be fed before the fish feed, which can be pellet feed, bran, wheat, corn, chopped fish or Slaughterhouse waste, etc. The amount of daily feeding can be controlled to account for 3% to 4% of the total weight of the broodstock, so that the broodstock can be fed first to reduce the competition between the broodstock and the larvae.
In order to prevent crayfish broodstock and larvae from competing for feed, construction sites and broodstock devouring larvae, a good environment for the growth of larvae must be established. It is imperative to include broodstock, hen-less hens, and early ancestral mothers. The juveniles that have grown into larger sizes have been separated.
The specific operation method is to adopt a fixed cage for fishing, and select a cage with a relatively large mesh but not catch the young shrimp to catch the broodstock. If any of the broodstock that has been caught has eggs or cuddling, it should be put back for continued feeding. Other broodstock and grown crawfish can be listed directly, or they can be put into holding ponds for intensive cultivation. After reinstatement, they are used again or listed as broodstock (crayfish broodstock is used for up to 2 years and generally not recommended for 3 years). Large-sized shrimps that are caught can be used for prawn farming or sold, and should not be returned.
In the course of fishing broodstock and large-scale shrimps, after picking up the cage, you must first pick out the larvae and the brooding broods. Do not injure them and treat other shrimps. If the density of larvae in the pond is felt to be too large, a certain amount of cages with dense eyes can be properly added, and part of the larvae can be caught and placed in separate ponds for cultivation or sale.
Water quality management
Water level control: After the rice is harvested, it is watered and deepens the surface water level from 30 cm to 40 cm.
Timely water exchange: Conditional water can be regularly sprinkled with a certain amount of biological agents such as photosynthetic bacteria and nitrifying bacteria.
Adjust the pH value: Splash lime water once every 15 days to maintain the pH between 7.5 and .5, at the same time increase the concentration of calcium ions in the water, and promote crayfish growth.
Poor water quality treatment: Once the water quality is found to be corrupted and crayfish come ashore, climb or even die, measures must be taken to improve the aquaculture water environment as soon as possible. Specifically, the following emergency methods can be used: (1) firstly replace part of the old water, and use chlorine dioxide to disinfect the water body and then add new water; (b) the next day, you can use zeolite powder to add water to sprinkling or sprinkling with beneficial bacteria. Use beneficial bacteria preparations to form dominant bacteria to inhibit the population, growth, reproduction and damage of pathogenic microorganisms, and decompose harmful substances in water, increase dissolved oxygen, and improve water quality. The application of photosynthetic bacteria, nitrifying bacteria, Bdellovibrio, Bacillus, Bifidobacteria, yeasts, etc. can play the role described above.
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