(1) area and depth of aquaculture pond
Earth ponds are the main ones, and the area can be large or small, and the water depth is required to be above1.5m. When the area of a single pond exceeds 10 mu, plastic nets should be inserted at the bottom to separate the ponds, so as to prevent Portunus from killing each other due to the change of water temperature and water quality.
(2) the bottom of the pool
Incline slightly from one end of the water inlet door to one end of the drainage door to facilitate water inlet and drainage. The bottom material should be sandy and muddy, and wavy furrows and ridges should be opened at the bottom of the pond. Concealed objects (such as waste pottery, stones, tiles, nets, bamboo, branches or shells in waste woven bags, etc.). ) should be set up in the pond as a hiding place for swimming crabs (especially during the shelling period). Pay attention to the use of woven bags must be cleaned.
In a pond with too much silt, medium-coarse sand with a thickness of about 10 cm can be partially spread on the bottom of the pond to provide a better living and growing environment for Portunus.
(3) There is no pollution source around the culture pond, and the environment is safe.
(4) Each flood season can naturally absorb moisture for about 10 days, and it is equipped with a water pump to ensure the supply of aquaculture water at low tide.
(5) Appropriate oxygenation equipment shall be provided.
Second, the preparation before stocking
1, dredging and pest control
One month before the seedlings are released, the silt in the pond should be completely removed. Then use the disinfection drugs in the table below to destroy enemy, predator and pathogenic organisms.
Disinfectants commonly used in cleaning ponds
Drug name
Dosage used
Withdrawal period
quicklime
350 mg/L ~ 400 mg/L
7 days
Bleaching powder (available chlorine ≥28%)
Seawater 40mg/L ~ 50mg/L.
5 days
Fresh water15mg/l ~ 20mg/l
5 days
Dichloroisocyanurate
5 mg/l ~ 10 mg/l
10 days
Trichloroisocyanuric acid
4 mg/L ~ 8 mg/L
10 days
Tea seed cake
Seawater15mg/l ~ 20mg/l
7 days
Fresh water 60 mg/L ~ 90 mg/L
7 days
2, fat water
7 ~ 10 days before seedling release, after the toxicity of disinfection drugs disappears, filter the water for 40 ~ 60 cm with a 60-mesh sieve, then apply 20 mg/L nitrogen fertilizer, or apply fermented organic fertilizer such as chicken manure to cultivate the basic bait, so that the pool water is yellow-brown or yellow-green, and the transparency is 30 ~ 35 cm. Or put some shellfish, such as Meretrix meretrix, Meretrix meretrix, etc. as polyculture varieties, so as to facilitate the adjustment of water quality and sediment in the middle and late stage of culture or as live bait.
Third, stock trading.
Specification and quality of crab seedlings.
The artificial crab seedlings are selected from stage II to stage III at 65438 0 days to 2 days after molting (the length of the shell is about 65438 0.0 cm). It requires neat specifications, strong individuals, strong vitality, no disease and complete body appendages.
2. Crab seedling transportation
Water transportation should be adopted: 0.8m× 0.4m plastic bags should be used to pack 10kg water, and sterilized straw or fluffy seaweed should be soaked in seawater as a cover to prevent young crabs from being injured by holding a group. Each bag contains 50g ~ 100g young crabs, and the mouth of the bag is tightly tied. It is required to be transported to the culture pond within 10h as far as possible.
3. Intermediate cultivation and seedling density
The young crabs of stage ⅱ ~ ⅲ should be cultured in the middle, and when they grow to 3 cm ~ 4 cm (100 ~ 200/kg), they should be cultured in the culture pond.
Intermediate culture adopts an intermediate culture pond with the size of 1 mu ~ 3 mu, or a small area of water is enclosed by net cloth in the middle of the pond for intermediate culture, which requires that the bottom of the pond can be drained to facilitate harvesting. It is also necessary to build shelter or properly spread sand to cultivate water color.
The density of intermediate culture is 15 ~ 20 cells /m2, the water level in the pond is 70 ~ 80 cm, the transparency is about 30 cm, the dissolved oxygen is above 5 mg/L, and the water is changed by 20% ~ 30% every day. The bait is mainly shellfish or small fish and shrimp, which are mashed and fed 2 ~ 4 times a day, and the feeding amount is 100% ~ 200% of the crab weight, preferably within 2 hours. At the same time, make appropriate adjustments according to the molting, climate, food intake and other factors of crabs. After 10 days to15 days of cultivation, when the width of the carapace reaches 3 cm to 4 cm, it can be put into a cultivation pool for cultivation.
The stocking density should be reasonably arranged according to the seed size, seedling release time, pond size, quantity of artifacts, bait situation and pond water quality. Generally, the stocking density should be 2000-2500 animals/mu during intermediate feeding. If young crabs of stage Ⅱ ~ Ⅲ are directly cultured, the stocking density should be 4000 ~ 6000/mu.
Fourth, training management.
1, feed feeding
(1) feed type
Low-value shellfish is the best, followed by low-value fresh mixed fish and shrimp. Advocate the use of compound feed to make up for the shortage of natural bait. It is required that the content of crude protein in compound feed should be above 35%, and the quality should meet the requirements of GB 13078 and NY5072.
Before feeding fresh bait, the shellfish with thick shells should be mashed and the big fish and prawns chopped. Pay attention to clean the fresh bait. When feeding non-shellfish bait, shell powder should be added to the bait if possible to prevent Portunus trituberculatus from growing slowly or having difficulty in shelling.
After mating, Portunus trituberculatus should be fed with high-quality bait rich in protein and unsaturated fatty acids (such as Nereis) to promote the gonad development of female crabs.
(2) Feeding quantity
The reference values of feed rate are as follows:
Weight of crab (g) Food intake is calculated by weight (%)
Below 0.8 100
10-30 50~30
50 12~8
Above 100 8 ~ 5
According to the water temperature, water quality, weather, food intake, physiological conditions, diseases and other factors, the daily feeding amount is appropriately adjusted.
(3) Daily feeding frequency
Generally, it is fed twice a day, 70% of the total amount in the evening and 30% of the total amount in the morning.
(4) Feeding method
It is advisable to feed them evenly in the whole pond to reduce the chance of Portunus gathering and killing each other. In addition, Portunus trituberculatus in the shelling stage can be fed on site, and each pond is equipped with 3 ~ 5 bait tables to check the feeding situation and residual bait quantity.
2. Water quality management
(1) water quality requirements
—— Water temperature growth The water temperature range is 12℃ ~ 32℃
The optimum water temperature range is 20℃ ~ 27℃
The water temperature for stopping eating is 8℃
Dormant water temperature 6℃
Chilled water temperature 2℃
-Salinity growth Salinity ranges from 20 ‰ to 30 ‰
The optimum salinity range is 10 ‰ ~ 34 ‰.
——PH 7.8~8.5
-The color of water, brown or yellow-green.
-The transparency is 30cm ~ 40cm.
-dissolved oxygen ≥ 4.0mg/L.
-Ammonia nitrogen ≤0.5 mg/L
—— Hydrogen sulfide ≤0. 1 mg/L.
(2) Water quality control
When the crab seedlings are just stocked, the depth of the pond water is 40 cm ~ 60 cm, and water is added every 2 ~ 3 days after the seedlings are released, and the water is added about 10 cm every day. After the pool water is increased to 1.5m, the water should be changed according to the water quality color, and the application of fertilizers, microecological agents and water quality improvers should be combined to maintain the water quality requirements of Portunus trituberculatus.
Under the conditions of high temperature and strong cold air, the water level in the pond should be raised, especially in the mating season of Portunus trituberculatus from August to 65438+1October, and the highest water level should be maintained to ensure the stability of the water environment, so as to facilitate the smooth mating of Portunus trituberculatus. In case of continuous rainstorm, the seawater should be drained in time and injected with fresh seawater to keep the seawater salinity above 1.5‰ to prevent the seawater salinity from dropping suddenly. In case of red tide, stop changing water.
If the PH value is too high, the PH value can be reduced by applying drugs such as copper chelate and norepinephrine. If the PH value is too low, it is advisable to apply 5 mg/L ~ 15 mg/L quicklime every half month, which can not only stabilize the PH value of water body, but also provide calcium source.
In hot season, especially in sultry weather, swimming crab will be deprived of oxygen due to the decomposition of residual bait, feces and biological corpses, so it is necessary to start the ground oxygen machine to increase oxygen.
3. Male and female are raised separately
When the crab body reaches about 100g, the male and female can be distinguished. At this time, the male crab with the number of female crabs of 1/3 ~ 1/5 should be raised together with the female crab, and another male crab should be raised separately. Male crabs should be caught and sold in time after mating to avoid affecting the gonad development of female crabs or losing male crabs because of their death after mating.
4. Prevention and treatment of diseases
Due to bacterial infection or other biological parasitism, various diseases (such as abnormal black spots, perforation on the shell, etc.) appear in the bottom-deteriorated aquaculture pond. ) will appear in the shell, abdomen and gills of Portunus, affecting the survival rate.
Disease control should mainly do the following:
-filtering the aquaculture water to prevent the enemy from entering;
-regularly disinfect water bodies with quicklime, bleaching powder and chlorine dioxide to improve water quality and sediments;
-keep the aquaculture water environment stable and prevent the stress reaction of Portunus trituberculatus;
-Feed high-quality fresh bait, and add appropriate disease prevention drugs to the bait at high temperature. Drug use should comply with Zhoushan Local Standard Regulations on the Use of Drugs for Healthy Aquaculture (DB330900/T006—2002), and it is recommended to use antibacterial and antiviral Chinese herbal medicines, such as allicin and other bait (according to the instruction manual). Put an end to the use of highly toxic and residual fishery drugs.
5. Daily management
(1) patrol the pond
Patrol the pond every morning, noon and evening to observe the changes of water quality, the activities of swimming crabs, the occurrence of diseases and the safety of dams and other facilities. 2 hours after each feeding, check the feeding situation of crabs and the remaining bait quantity, so as to adjust the bait quantity in time.
(2) Water quality testing
Daily measurement of water temperature, dissolved oxygen, pH value and transparency, and regular measurement of salinity, chemical oxygen consumption, ammonia nitrogen and other water quality factors.
(3) determination
Measure the growth of crabs every ten days, and measure the breeding effect by measuring the length, width and weight of nails.
(4) Breeding records
A breeding log should be established for each aquaculture pond, which includes pond cleaning, provenance, species specification, stocking quantity, stocking date, water quality control, feed source, feed type, feeding quantity, morbidity, drug type, fishery drug name, fishery drug manufacturer, drug dosage, drug quantity, administration mode, administration frequency, output and sales destination, etc.
Step 6 harvest
(1) capture time
Male crabs can be harvested and put on the market in June 5438+065438+ 10 after fattening separately, and female crabs can be put on the market one after another when their gonads mature in June 5438+mid-February. If you want to continue selling before and after the Spring Festival, you should raise the water level or keep the water temperature above 2℃ in a plastic greenhouse.
(2) Fishing methods
-drift net capture: release the drift net in the evening, close the net every 2 hours, and capture it 4 ~ 5 times a night.
-Crab cage capture: the crab cage is released at night, collected every 3 hours and captured 3 times every night.
—— Net bag catching: fix the net bag at the gate of the drainage gate, and release water when the tide ebbs, so that the swimming crab can enter the net bag with the current, and some swimming crabs can be caught.
-Dry pond fishing: drain the pond water to the lowest place, slowly rake it along the bottom of the pond with an iron rake, stir up the crabs, and fish them up with a net by hand.
The captured big pincers of Portunus trituberculatus were tied tightly with rubber bands, washed with seawater, put into a laundry list, dried and transported to the market (at the temperature of 2℃ ~ 4℃, the survival rate of Portunus trituberculatus in dew for 24 hours was 90%).
I copied someone else's. I hope I can help you.