At present, according to the different breeding processes, squid breeding methods can be divided into artificial whole-course breeding, fattening temporary breeding and storage temporary breeding. The whole process of artificial breeding is to raise artificial fry of about 2 cm or natural fry of 3 ~ 7 cm, and cultivate them until they are sold as adults. Fattening and temporary rearing is the process of cultivating thinner adults or relatively small adults into fatter ones, or cultivating females into fertile ones and selling them after wintering. Temporary storage culture refers to the process of purchasing shrimp, storing it to a certain amount, transporting it to foreign markets or exporting it in fresh form to earn regional price difference.
According to the different forms of culture sites, crayfish culture methods can be divided into two types: low dam and high net culture and soil pond culture. Generally speaking, aquaculture ponds with low tidal flat dams and high nets are built in harbors with less wind and waves and on wider flat tidal flats. Its area is 5 ~ 50 mu, depending on the number of seedlings. The dam is 0.6m high and 1.0m wide, with a flat bottom and a slight inclination to the harbor center. On the center line of the dam, the polyethylene net phase diagram with a mesh of about 4 mm (the larvae of shrimp or the third-stage pseudofleas cannot escape) is fixed with bamboo strips and ropes; Cover the dam surface in the purse seine with a fine net (about 1 m away from the purse seine) to prevent shrimps from escaping; Before harvesting shrimp, install a conical net at the lowest part of the culture pond for harvesting. It is required that the area of the culture soil pond is several acres to several tens of acres, the height of the pond embankment is 2.0 ~ 2.5 meters, and the water depth is 1.5 ~ 2.0 meters. It is equipped with a sluice to drain the water from the pond and installed an escape net. The soil at the bottom of the pond should be soft and there should be no black sapropelic mud. At present, most shrimp ponds can be used to raise shrimp, but the black sludge at the bottom of the pond must be removed.
There are many kinds of shrimp, but not all of them are worth breeding. Generally, varieties with large size, fast growth, easy seedling, strong adaptability to salinity and temperature and high market price are selected for breeding. At present, the species that have been cultivated in Zhejiang Province are the black-spotted shrimp, the thorn-billed shrimp and the oral shrimp. In addition, octopus ocellatus and octopus ocellatus along the coast of Guangdong are all over 30 cm in length, and the market price is equivalent to that of lobster, so they are also promising breeding varieties.
Seedling preparation
There are two sources of breeding seeds: artificial seeds and natural seeds. Since the artificial breeding of squid has not reached the productive mode so far, the fry mainly come from natural sea areas. Natural seedlings are mostly caught by fixed nets and bottom trawls, and some are directly caught by hand in caves on the beach. The net catching time should not be too long to avoid crushing or damaging the seedlings for a long time. Seedlings can be transported by oxygenated water or dry and wet transportation, and the transportation time should be controlled within 10 hour to ensure the survival rate of transportation. Pay attention to avoid high temperature, sun, rain and wind during transportation; In high temperature season, it is advisable to transport at night or use ice cubes to cool down. If the natural seedlings are in different sea areas, we should pay attention to whether there are differences in water temperature and salinity, and the transition method must be used if there are big differences.
Squid culture can be carried out all year round, and the stocking season is mainly determined according to the cultivation of artificial fry in the local sea area and the flourishing time of squid fry. In the coastal areas of Zhejiang, shrimps usually appear from April to 10. In April-June, there are the most young shrimps, and in June-August, the young shrimps and young shrimps are flourishing. Although squid can overwinter naturally, its growing season is in spring, summer and autumn when the water temperature is higher than 15℃.
Site preparation
The pond must be cleaned before the shrimps are released. Although mantis shrimp preys fiercely, it also has natural enemies, such as eel and goby. Therefore, the enemy bacteria and pathogen must be removed before stocking. If natural enemies are found in farming, they should be eliminated as far as possible. Generally, the pool cleaning should be carried out in advance according to the validity period of the pool cleaning drugs. Choose sunny weather, drain the pond water as much as possible when the tide ebbs, and sprinkle high-concentration quicklime (300× 10-6). It can also be disinfected with 200× 10-6 bleaching powder.
Stocking technology
Reasonable stocking density of fry is one of the factors of successful breeding. The stocking density of crayfish should depend on pond conditions, fry quality and specifications, bait supply and aquaculture management level. Generally, the natural larvae caught at sea are large, with a body length of more than 3 ~ 6 cm, and 5,000 ~ 7,000 fish can be released per mu; If the artificial seedlings of about 2 cm are stocked, the stocking density can be appropriately higher, about 8000/mu; If the larvae of the third stage of Penaeus monodon are released, the release amount is 654.38+500,000 ~ 30,000 tailwalls.
In order to make full use of the water body and improve the breeding efficiency, other aquatic products can be mixed in the shrimp pond. Raft culture should mix fish, shrimp and shellfish in the upper and middle waters to avoid competing with shrimp for the bottom area of the soil pond.
Pay attention to the following problems when releasing seedlings: the difference of temperature and salinity, and the quality of shrimp seedlings. The difference between temperature and salinity can be eliminated by floating seedling bags in pond water and gradually adding pond water. The quality of shrimp can be distinguished according to its shape, vitality, body color and activity state. Good quality seedlings have strong vitality, bright body color, hard shell and complete appendages, and can swim quickly after entering the water without turning around locally or turning white at the bottom.
In order to estimate the survival rate of crayfish fry, a certain number of fry can be temporarily raised in small cages for inspection.
Bait technology
Because the third-stage pseudoflea larvae and larvae of shrimp widely eat benthic crustaceans, polychaetes, small fish, bivalves, cephalopods and hydrangeas, if artificial larvae are raised, it is best to cultivate basic bait to prevent poor growth or death caused by artificial feeding and improve the survival rate; If natural fry with large individuals are stocked, it is not necessary to cultivate basic bait because of their strong feeding ability and adaptability to artificial feeding.
Because shrimps are omnivorous, ordinary aquatic species can also eat them. Commonly used bait varieties are small miscellaneous fish, shrimp, shellfish and so on. However, fresh platypus is the best, which can reduce the pollution of the bottom material. Feeding should be even, and it is more appropriate to feed every evening. If you feed large fish, shrimp or shellfish with thick shells, you need to cut the food into small pieces or break the shells in advance.
The feeding amount shall be subject to the feeding rate, and shall be appropriately adjusted according to individual size, physiological condition, water temperature, weather conditions, feed types, freshness and water quality. Before the body length is 7 cm, the feeding amount is 0% ~ 40% of the total weight of shrimp; The body length is 8 ~ 1 1 cm, and the food intake is11%~ 20% of its total weight; The body length is more than 12 cm, and the food intake is about 10% of its total weight.
The influence of water temperature change on the growth of crayfish is mainly realized by the influence of water temperature on its food intake. When the water temperature is lower than 15℃ or higher than 32℃, the food intake is obviously reduced and the growth is obviously slowed down, so it is necessary to reduce the feeding amount. If it is in the spring and summer breeding season, the shrimp's food intake will also be greatly reduced due to the breeding activities, and the food intake will also be reduced. In addition, shrimp don't like to eat stale bait, and it is easy to pollute water quality and sediment, so throw it as little as possible.
Proper feeding amount is the guarantee for the normal growth of prawns. Hunger has obvious influence on the growth of prawns, and small individuals are more sensitive to hunger than large individuals. However, the excessive feeding of bait leads to the decay and odor of residual bait, which leads to the deterioration of water quality and sediment, which seriously threatens the shrimps who rely on sediments to build their nests. Therefore, the feeding amount should be strictly controlled and the feeding situation should be observed frequently. It is a common bait inspection method to set up a bait table and observe the silt in the pond.
Water quality control
The purpose of aquaculture water quality management is to keep the water temperature, salinity, dissolved oxygen, transparency, water color and biological density in the pond within the optimal growth requirements for aquaculture varieties, so as to facilitate the normal growth of aquaculture varieties and achieve the purpose of high and stable yield.
Squid is a typical intertidal organism and has strong tolerance to changes in temperature and salinity. However, the high density of squid often causes the change of water quality, so it is necessary to carry out water quality management. The daily work of water quality management is to measure and record water temperature, salinity and dissolved oxygen 1 ~ 2 times a day. Depending on the water quality of the pond, decide whether to change the water properly. The dissolved oxygen is kept above 4 mg/L, and the transparency is controlled at 30 ~ 50 cm. In summer, the water level in the pond should be raised, and the fresh water and cold water in the open sea should be replaced as much as possible to keep the water temperature within 33℃, so as to avoid the influence of high water temperature on the feeding growth or death of shrimps. When the water temperature was higher than 33℃, the squid died obviously. In winter, the water level should also be deepened to prevent freezing to death if the water temperature is too low (< 5℃). Although Squid has a wide adaptability to salinity, we should pay attention to the sudden change of salinity where the salinity changes greatly. During culture, 2× 10-6 quicklime can be added every 10 ~ 15 days to improve water quality and sediment, and also increase calcium in water, which is beneficial to shrimp and disease prevention.
Monitoring management
Squid grows faster. Under normal circumstances, its body length can increase by 0.9 ~ 1.0 cm every ten days. Generally speaking, the growth of crayfish body length is faster in the early stage of culture than in the later stage. In the breeding season, the female individual's body length does not increase, because the energy it absorbs is used for gonad development, and it can continue to grow after the breeding period. The experiment showed that the growth rate of the black-billed shrimp was faster than that of the black-billed shrimp under the same conditions.
Growth measurement is generally carried out every 10 day 1 time, and the samples are trapped with cages. In order to ensure the accuracy of measurement, more than 50 samples are needed for each measurement. Because of the burrowing life of shrimp, it is difficult to estimate the number of shrimp in the pond by a simple method, but it can be estimated according to their ten-day growth, food intake and water quality conditions such as water temperature at that time.
In shrimp culture, the following daily management work should be done well:
(1) Always check whether the building blocks are damaged and remove the sundries or dirt hanging on the Internet.
(2) Check the dam for leakage or gap, and repair it in time if found.
(3) Regularly check the feeding situation of shrimps, take samples for dissection, and observe the stomach contents.
(4) Check the residual bait, enemy damage and sediment at low tide or when releasing water.
(5) Sampling every 10 day to determine its growth. If the body length increases more than 0.9 ~ 1.0 cm every ten days, it is normal. If you don't meet this requirement, you must find out the reason.
(6) Observe the living habits such as digging holes and shelling. If it is found that shrimp refuse to dig holes during the day, it means that the sediments may be seriously polluted or lack of oxygen.
(7) Pay attention to weather changes and water quality in the harbor. If the weather is abnormal, take preventive measures in time; If the water quality such as red tide is found to be unclean, it is not suitable to enter the water, and oxygen should be strengthened.
harvest
Shrimp can be caught and sold according to market demand after reaching the commodity specifications. According to the survey, the market price mainly depends on individual size, fatness and female gonad development. Shrimp with general size 1 1 cm and good fatness has a stable market sales; In the breeding season, as long as the female gonads are well developed, even if the individual is slightly smaller (the female can mature sexually at about 8 cm), it is also popular. Because of its cave dwelling, its fishing method is very special. According to their living habits, shrimp culture mainly adopts the following fishing methods:
(1) net catching: In the season when the water temperature is above 15℃, this method is simple and labor-saving, and can generally catch more than 90% of the total. However, this method is only suitable for fishing at low tide at night, and you can't feed on the night of fishing, because shrimp have the habit of hunting during the day and going out at night, and they make holes after eating. The specific method is as follows: first, put the net in the groove of the sluice. When the tide ebbs at night, open the sluice to release the pool water, and the shrimp will flow downstream into the net. After the water in the pool is drained, recharge it at high tide and fish again the next night. So repeatedly.
(2) Pull-net fishing: In the middle and late stage of shrimp culture, due to the market situation, this method should be used for intermittent fishing or catching big fish and keeping small ones. It is better to throw bait in the ground dragon net than to throw bait in the breeding pond that night. Tommy Tam net is a trapezoidal fixed net with a T-shape. It has many entrances and a bag net, and each entrance has inverted whiskers, so it is difficult for shrimp to get out of the net and the bag net is caught. When working, the net is placed in the pond, and the shrimp gets into the net when they come out of the hole for food at night. The next morning, pour it out of the bag net. According to the demand and area, a certain number of ground dragon nets are placed for fishing.
(3) Dry land fishing: The shrimps left after the above two methods of fishing, or those that have wintered in caves due to low water temperature, should be fished in dry ponds. The specific method is: first drain or pat the pool water dry, and you can see the shrimp hole at the bottom of the pool. The U-shaped squid hole has two nearly circular exits, one large and one small. Run in through the big hole with your feet, push a few times, and the shrimp will climb out of the small hole. Because of the high density during cultivation, caves are often connected; Or in winter, the cave becomes a "Y" shape, and it is difficult for the foot to have an effect, so we have to dig with other tools. In this way, the shrimps raised in the pond can basically be caught hole by hole.
If other swimming fish and shrimp are mixed and need to be caught at the same time, they can be caught with nets; If you don't harvest at the same time, it is not advisable to drain the pool water. You should harvest it several times, or choose several fishing methods for mixed use.