CATDOLL : CATDOLL: How to carry out hanging culture of pleated oysters with seedlings in the season with lower temperature?

1. How to carry out hanging culture of pleated oysters with seedlings in seasons with lower temperatures?

A method of oyster farming that involves hanging seedlings of Crassostrea gigas in autumn. It can fully utilize the semi-reclaimed shallow sea mudflats in the lower part of the low-tide zone and the rich plankton bait in the lower seawater, increase the oyster feeding time, and tap the production potential of marine aquaculture, thereby increasing oyster production and economic benefits. Hanging seedlings are raised around August and can be put on the market in June of the following year, and harvested until the end of September.

(1) Materials and methods

Three methods of oyster culture are adopted: scaffolding type and floating platform type. Oyster shells are strung together with polyethylene ropes as the attachment matrix, and the best tide area for seed attachment is selected for centralized seed attachment. After the seed is seen, it is moved to the lower edge of the low tide area or the shallow sea breeding platform, or the gap between oyster stones for cultivation. For the scaffolding type, the shell string is generally 2 meters long, the shell distance is 0.1 meters, the main rope is 50 meters long, the horizontal cable is 40 meters long, the foot rope is 5 meters long, the seedling hanging rope is 0.5 meters long, and the pile is 1.2 meters long, or the stone foot is 1.8 meters long, the row spacing is 2.2 meters, and the string spacing is 0.2 meters. It is designed according to 2 mu per hill and 5 sets per mu; for the floating platform type, the shell string is generally 2 meters long, the floating rope is 50 meters long, the horizontal cable is 40 meters long, the anchor cable is 15 meters long, the seedling hanging rope is 0.5 meters long, the floating length is 1 meter, the pile is 2 meters long, the shell string is 0.15 meters wide, the string spacing is 0.25 meters long, the row spacing is 2 meters long, the float spacing is 4 centimeters, and the pile spacing is 50 centimeters. It is designed according to 4 mu per hill, 5 sets per mu, and 2 mu. Oyster stone breeding, that is, the original oyster stone breeding stone bridge is used for cage breeding, and the two ends of the seed rope with attached seedlings are tied to the stone bridge feet or tied firmly in the oyster stone interval.

(2) Seedling attachment operation procedures

The seedling attachment area should be selected in a flat area, and refer to the areas where oyster stone seedlings are better all year round. Generally, the seedling collection site can be in the middle tide area and the middle and lower area of ​​the intertidal zone, close to the sea route for easy operation and transportation. Before attaching the seedlings, complete the piling and tying process to avoid loose placement. The rack is about 40 cm above the ground, and the seedling attachment base is arranged. Generally, 10 strings are tied into a bundle, and tied tightly to be orderly. When attaching seedlings, centralized seedling attachment should be adopted. At the beginning of the seedling collection season, each bundle of attachment base is arranged in sequence on the seedling collection rack or stone bridge, and the safety rope is sealed. Generally, the shell string is not higher than 60 cm from the ground. If it is too high, it is easy to attach barnacles. If it is too thick, the seedling attachment is uneven, and the accumulation of sludge affects the seedling collection effect. The seedling collection should be controlled in the rainy weather in autumn when the water temperature is high and the specific gravity of seawater is low. If the visceral mass of the parent shell suddenly becomes thin and the gonads change from milky white to transparent, it indicates that hot ovulation has occurred. The seedlings can be collected 7 to 10 days after ovulation. From the time of collecting seedlings to the time of hanging them for culture, you should go to the sea frequently to check the attachment of seedlings, and wash away the shells and sludge in time to ensure that there are enough seedlings.

(3) Cultivation management

Frequently go to sea for patrol to prevent enemies, timely check and repair shell strings and buoyancy of the platform, and the safety and firmness of the main rope, cross cable, and tripod piles. As the oysters grow, the load of the platform increases, and the buoyancy should be increased in time to prevent the shell strings from being suffocated by mud. In the late growth period, most oysters are crowded together, and the impact of wind and waves can easily cause the oysters to fall off, so they should be collected or harvested at the right time.

You can plant some aquatic plants in the canteen, and also strengthen the temperature control of the pond, so that better breeding can be carried out.

How to carry out hanging culture of Crassostrea gigas in the season with low temperature? Find a way to implement heat preservation policy, raise the temperature of the pond to ensure its survival rate.

During the breeding season of Crassostrea gigas, broodstock dissections are carried out, gonad fatness is tested, water samples are taken to check the number and developmental stage of larvae in different water layers of the sea area, seed attaching devices are set up to observe the amount of attached seeds and barnacle attachment in different tidal zones, at different heights and on different dates, as well as tests on the physical and chemical factors of the sea area, such as water temperature, specific gravity, pH value and other related factors. Combined with other conditions of the sea area that year, analysis and judgment are made to make accurate forecasts for seed collection time.

2. What is the most reasonable feed for oyster farming?

Oysters are usually suspended in the sea and usually do not require any feed. They filter algae and cladocerans from the seawater for food. The management is extensive and no feed is given artificially.

3. Is it necessary to plant seeds when raising oysters?

. Oyster spawning is mostly carried out during high tides. When the water temperature is 23℃, the fertilized eggs develop into D-shaped larvae after 20-22 hours. Under the condition of water temperature of 23-26℃, after about 20 days of cultivation, the average shell length of the D-shaped larvae can reach more than 280μm, and 40%-50% of the larvae have eyespots. At this time, the attachment base should be released to allow the larvae to metamorphose and attach. 3. Seedling production At present, there are two ways of oyster farming: fully artificial seedling cultivation and semi-artificial seed collection. The operation process of fully artificial seedling cultivation includes: temporary cultivation and ripening of broodstock, egg collection, hatching and selection, bait and larval cultivation, preparation, processing and release of attachment base, and juvenile spat out of the pond; the operation process of semi-artificial seed collection includes: selection of seed collection site, examination of broodstock gonad development, collection and investigation of planktonic larvae, preparation, processing and release of attachment base, etc. 4. Cultivation: There are many methods for oyster farming. With the continuous development of farming, new farming methods and technologies are constantly emerging. The more common ones are bamboo planting, bottom seeding, strip and standing stone, and hanging farming. Hanging farming is divided into grid, longline and raft. Regardless of the farming method, the key is to choose the breeding site, which should be determined according to the living habits of oysters and their requirements for environmental factors and within their adaptability range.

4. Can oysters be farmed in freshwater? Experts, please give me some advice

No, that's for sure.

5. How do oysters grow?

Oyster

There are two types of oyster reproduction: larval and oviparous.

Oyster: A general term for the family Ostreae, order Ostreae, class Bivalvia, phylum Mollusca. Also known as sea oyster.

During the breeding season, the parent of the oviparous oyster discharges mature sperm and eggs from the body. The sperm and eggs are fertilized in the seawater. After a period of floating life, they attach to other objects and metamorphose into juvenile shellfish after fixation. Most of the cultured species belong to this type. During the reproduction of the juvenile oyster, the parent discharges mature reproductive cells into the water outlet cavity. Relying on the action of the mantle and gill muscles near the drainage hole, the reproductive cells are pressed into the gill cavity and fertilized here. The embryo develops into a veliger larva and leaves the mother body. After a free floating stage in the seawater, it attaches and metamorphoses into juvenile shellfish. The dense-scaled oyster belongs to this type.

When oysters reach one year old, their gonads mature and they begin to reproduce. There are two types of reproduction: larval and oviparous. The dense-scaled oyster is a larval type. After the eggs mature, they are placed in the mother's mantle cavity between the gills for fertilization and hatching. After developing to the veliger stage, they are released into the seawater for a planktonic life, and then metamorphose into adults for a fixed life. The long oyster is oviparous and fertilized externally. The vast majority of long oysters are hermaphrodites, and a small number are hermaphrodites. When the gonads mature, the males are milky white and the females are light yellow. When the water temperature in the natural sea area rises to 16°C, the gonads of the long oyster begin to mature, and the peak spawning period is when the water temperature reaches 24-25°C. The peak breeding period in the Yueqing Bay area of ​​Zhejiang Province is from June to July. Oyster spawning mostly takes place during the high tide. When the water temperature is 23℃, the fertilized eggs develop into D-shaped larvae after 20-22 hours. When the water temperature is 23-26℃, the D-shaped larvae are cultivated for about 20 days. The average shell length of the larvae can reach more than 280μm, and 40%-50% of the larvae have eyespots. At this time, the attachment base should be put in so that the larvae can metamorphose and attach.

The finished oyster cake is round, golden in color, crispy and fragrant, with delicious stuffing and meaty taste. It can be eaten alone. Most people in Fuzhou make oyster cake as a side dish for porridge. If eaten with Dingbianhu, one is dry and the other is thin, the flavor is delicious.

As mentioned before, eating oysters raw is a popular method.

Maupassant's "My Uncle Jules" has a description: "Two beautifully dressed ladies eat oysters. They eat them very elegantly. They hold the oysters with a small handkerchief, lean their heads forward slightly to avoid staining their robes, then move their mouths slightly to suck in the juice and throw the shells into the sea."

Buffets in Western restaurants usually have raw oysters. A fellow countryman in Vancouver said that in Canada, a plate of oysters has six types, two of each, for a total of twelve. The most particular thing is how to eat them, with different wines for different oysters. But it is not easy for a gourmet to reach this level. However, in the current environment, there is a lot of pollution along the coast, so eating raw oysters may not be suitable.

There are two other ways of eating recommended by gourmets: one is fresh oyster hot pot, and the other is fried dried oysters. Let's talk about fresh oyster hot pot first. The gourmets require that mineral water be used as a clear soup, add a little ginger slices and coriander, boil the oysters in the water for about 1 minute, and then it can be eaten. When eating, dip it in the seasoning ginger and garlic sauce, it will be sweet and delicious. However, remember not to add soy sauce to the sauce, as gourmets say soy sauce will destroy the freshness of the oysters. The other is fried dried oysters, using raw sun-dried oysters (dried raw oysters, not the so-called dried oysters mentioned above) as the raw material, and then fry the raw sun-dried oysters until they are slightly charred and put them on the plate. When eating, add some sugar, which is sweet and chewy, highlighting the characteristics of the taste of dried oysters (raw sun-dried oysters, called oyster drums in Guangdong), which is endless aftertaste.

Oysters are not only tender and delicious, but also rich in nutrition. They are known as "milk in the sea". They contain a variety of nutrients such as vitamins, taurine, glycogen and other minerals. The iodine content is 200 times higher than that of milk and egg yolks. The zinc content is the highest among other foods. The Compendium of Materia Medica says that eating more oyster meat can "clean the skin, nourish the kidney and strengthen the yang, and can also treat deficiency and relieve erysipelas." The Tangye Materia Medica says that oysters "are a softening agent. Using Bupleurum as a guide can remove the hardness under the ribs; using Rong as a guide can eliminate tuberculosis on the neck; using Rhubarb as a guide can eliminate swelling between the thighs; using Rehmannia as a guide can replenish essence, astringe and stop urination. This is a medicine for the blood of the kidney meridian." The Supplement to Materia Medica says: "Cooking it is mainly for deficiency, women's blood and qi, regulating the middle... Eating it raw in ginger and vinegar can treat erysipelas, fever after drinking, and quench thirst." The Medical Collection says: "Sweet and salty, cold. Clears the lungs and nourishes the heart, nourishes Yin nourishes blood. "Food Secretary" says: "clears heat, regulates the middle, makes people delicate skin and beautiful complexion." "Pharmacopoeia of the People's Republic of China" records that oysters "calm the mind, nourish yin and tonify yang, soften and disperse nodules, astringe and consolidate, used for palpitations and insomnia, dizziness and tinnitus, scrofula and phlegm cough, abdominal masses and lumps, spontaneous sweating and night sweats, spermatorrhea, metrorrhagia, and acid reflux." Oyster diet therapy is suitable for insomnia, restlessness, spontaneous sweating and night sweats, spermatorrhea, and stomach acid reflux caused by long-term illness and blood deficiency or Yin and fluid depletion after fever.

According to unofficial historical records, Napoleon loved to eat oysters during his campaigns to maintain his fighting spirit. Some also said that Caesar's expedition to Britain was to obtain the plump oysters from the Thames River. Balzac was proud of eating 144 oysters a day. Soong Mei-ling also often ate oysters to maintain her beautiful face.

Note: This article uses sea oysters instead of oysters, which is actually not accurate. Some estuaries and bays also have artificial cultivation.

There are many types of oysters. According to statistics, more than 100 species have been discovered in the world, distributed in tropical and temperate zones. Oysters are widely distributed along the coast of my country, from the Bohai Sea, the Yellow Sea to the Nansha Islands, with about 20 species. There is also artificial breeding in the inner bays of estuaries, and oysters are divided into artificial breeding and natural reproduction. According to the records of Mei Yaochen in the Song Dynasty, people in the Song Dynasty not only knew how to eat oyster meat, but also coastal fishermen had already engaged in "raising oysters with bamboo" and cultivating oysters on the beach. The history of artificial breeding can be said to be long. The oysters that have been cultivated along the coast of my country include: long oysters, pleated oysters, offshore oysters, Dalian Bay oysters, Yangtze River oysters and dense-scaled oysters, etc.