CATDOLL : CATDOLL: What is an oyster??? A mouse???

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The shells of the oysters Ostrea gigas thunberg, Ostrea talienwhanensis crosse or Ostrea rivularis gould can be harvested all year round, the flesh removed, cleaned and sun-dried.

【Properties】Long oysters are in the shape of long flakes, with almost parallel dorsal and ventral edges, 10 to 50 cm long and 4 to 15 cm high. The right shell is smaller, with hard and thick fresh flakes, arranged in layers or stratified patterns, the outer shell is flat or has several depressions, and is lavender, grayish white or yellowish brown, with a porcelain white interior, and no small teeth on both sides of the shell top. The left shell is deeply concave, with coarser scales than the right shell, and a smaller attachment surface on the shell top. It is hard, with a layered cross section and is white. It is odorless and tastes slightly salty.

The Dalian Bay oyster is triangular in shape, with an eight-shaped dorsal and ventral margin. The outer surface of the right shell is light yellow, with loose concentric scales that are undulating in a wave-like shape, and the inner surface is white. The concentric scales of the left shell are thick and radiate from the top of the shell. They are obvious, and the inner surface is concave and box-shaped, with a small hinge surface.

Omi oysters are round, oval or triangular, etc. The outside of the right shell is slightly uneven, with gray, purple, brown, yellow and other colors, with concentric scales. The scales of the juveniles are thin and brittle, and after many years of growth, the scales overlap, the inside is white, and the edges are sometimes lavender.

[Nature and flavor and meridians] Salty, slightly cold. Enters the liver, gallbladder, and kidney meridians.

【Functions and Indications】It calms the mind, subdues yang and replenishes yin, softens and disperses lumps, and astringes and consolidates. It is used for palpitations, insomnia, dizziness, tinnitus, scrofula, phlegm nodules, masses and lumps, spontaneous sweating, night sweats, spermatorrhea, metrorrhagia, stomachache and acid regurgitation. Calcined oyster astringes and consolidates. It is used for spontaneous sweating, night sweats, spermatorrhea, metrorrhagia, stomachache and acid regurgitation.

【Storage】Place in a dry place.

(I) Cultivation methods 1. Raft culture: Choose sea areas with smooth tides, abundant bait, calm winds and waves, and a water depth of more than 4 meters as oyster raft culture sites. Oysters from the Yangtze River should be cultivated near estuaries with low salinity; oysters from Dalian Bay should be cultivated in sea areas far away from estuaries with high salinity; Pacific oysters and pleated oysters are in between. There are two main cultivation methods: (1) Rope culture: Suitable for oysters that use shells as a base for anchoring. There are two cultivation methods: one is to string the shells with oyster seedlings together with ropes, separate them with bamboo tubes about 10 cm in the middle, and hang them on the raft frame; the other is to clamp the shells with oyster seedlings in the twisted seam of a polyethylene rope with a diameter of 3 to 3.5 cm, clamp one shell every 10 cm, and hang them on the floating raft. Generally, each rope is 2 to 3 meters long. Rubber tires can also be used to clamp seedlings for hanging culture. (2) Net cage culture: Use scallop net cages for culture. Oyster seedlings without anchorage or attached to shells are placed in scallop net cages together with shells and suspended on floating ropes. Raft culture generally releases 100,000 oyster seedlings per 667 square meters. Shells are used as seed collectors, and about 10,000 shells can be suspended per 667 square meters. Oyster seedlings are released from May and June and harvested at the end of the year. The yield per 667 square meters can reach more than 5,000 kilograms. 2. Tidal flat seeding (1) Site selection: Tidal flat seeding should be carried out in inner bays with small waves, smooth tides and no pollution. Sandy muddy or muddy sandy beaches are preferred. Tidal areas should be selected at the lower part of the mid-tidal area and near the low-tidal area. (2) Seeding season: Generally, mid-March to mid-April is the most suitable time for seeding. In production, seedlings can be planted as late as mid-May. (3) Seeding method 1 Dry tide seeding: that is, seeding when the beach surface is dry and exposed after low tide. Before sowing, the beach surface should be leveled or built into a ridge-shaped base before sowing. For low-tide sowing, try to make sure that the tide starts to rise right after sowing to shorten the time that the oyster seedlings are exposed to the sun and avoid sowing when the seedlings are exposed to the sun at noon. 2. Sowing with water: Sowing by boat after high tide. Before sowing, divide the beach surface into strips and insert bamboo poles, wooden poles, etc. as signs. After high tide, scatter the oyster seedlings on the boat with a shovel. Since the distribution of oyster seedlings cannot be directly observed during sowing with water, uneven sowing often occurs. The density of sowing should be determined according to the quality of the beach and the fatness of the water. For excellent tidal flats, about 120,000 seedlings should be sown per 667 square meters, for medium ones, about 100,000 seedlings, and for generally poor ones, 60,000 to 80,000 seedlings can be sown. 3. Oyster and shrimp co-culture (1) Shrimp pond selection: For oyster co-culture, the bottom of the shrimp pond should be muddy or muddy sandy, with a water depth of more than 1.3 meters and an average daily water exchange rate of about 50%. The transparency should be controlled at 40-50 cm in the early stage and 50-60 cm in the middle and late stages. (2) Site preparation: Before stocking oysters, the silt should be thoroughly cleared and the bottom of the pond where the oyster fry are to be sown should be leveled and compacted with a bulldozer or other tools to form a slightly convex shape, slightly higher than the surrounding bottom surface, to prevent the oyster fry from sinking and being buried in the silt and dying. (3) Seedling sowing: Under the premise of ensuring the normal stocking density of shrimp, the sowing amount of oyster fry should be about 30,000 per 667 square meters. The sowing time should be selected in early April, and the seed size should be more than 2 cm in shell length. The sowing stress should be uniform, and the low-lying areas of the ring ditch and the feeding area should be avoided. The sowing area should account for 1/4 to 1/3 of the pond bottom area. 4. Stone-throwing aquaculture: The stones used as oyster seed collectors become the oyster cultivation equipment. The short-lived Crassostrea gigas can be cultivated in the seed collection field; the long-lived Crassostrea gigas must be moved to the cultivation field for cultivation. There are three main cultivation methods: star-shaped, plum-blossom, and row-shaped: (1) Star-shaped: Oyster stones are placed randomly. (2) Plum-blossom: Generally, 5 to 6 oyster stones form a group. (3) Row-shaped: The row width is 0.5 to 1 meter, and the row spacing is 0.6 to 1.5 meters. Deep-water aquaculture can be left unattended after stone-throwing until harvest. 5. Bamboo-throwing aquaculture: Using the bamboo-throwing method, the collected oyster seedlings are cultivated sparsely on the spot. There are two ways to arrange oyster bamboos during cultivation: (1) Straight insertion: 150 to 179 oyster bamboos are inserted in a row, with a length of 3 to 5 meters; or 100 to 120 oyster bamboos are inserted in a row, with 2 to 3 gaps in the middle of the row to facilitate water flow. (2) Oblique insertion: 23 to 26 oyster bamboos are inserted into a pile, with a bottom width of 45 to 60 cm and a top width of 33 to 36 cm. The distance between piles is 20 to 25 cm. A row is composed of 5 to 6 piles, with a distance of about 2.5 meters between rows. 8,000 to 10,000 oyster bamboos can be inserted per 667 square meters. 6. Bridge-type cultivation: After the seedlings are collected using the bridge-type seedling collection method, the stone bars are rearranged to disperse the density and then cultivated. Generally, 6 to 7 stone bars form a group, and the groups are connected to form a row with stone bars. The distance between groups is 50 to 60 cm, and the distance between rows is 1 to 2 meters. During the growing period, the shady side and sunny side of the stone strip should be interchanged to make the oysters grow evenly on both sides. 7. Standing stone culture: After collecting seedlings in the mid-tidal area using the standing stone seedling collection method, as long as the seedling quantity is appropriate, it can be left to grow naturally without any management until harvest. This method is mainly used for the cultivation of pleated oysters. 8. Grid culture: This culture method is to set up a fixed grid frame in the inner bay when the water depth is 2 to 4 meters, the wind and waves are calm, and the bait is sufficient. The setting of the frame is the same as the grid seedling collection. Oyster seedlings are mostly raised in strings on the grid frame with shells, cement tiles and other fixed bases in series. Each string is 1 to 1.5 meters long, and the distance between strings is 0.5 to 1 meter. The culture density should not be too high to prevent touching the bottom to avoid the invasion of certain benthic pests. (II) Management during the growing period 1. Turning the stone (moving the stone): It is to move the position of the oyster stone. Turning the stone can prevent oysters from being suffocated by silt and can also stir up the floating mud, increase the nutrient salt of the bait, and promote the growth of oysters. Generally, the stones are turned over 2 to 3 times during the culture period. 2. Flood prevention: In the rainy season, attention should be paid to preventing floods from flowing in, or digging ditches to prevent floods, or moving oysters to high-salinity deep-water areas for temporary culture. 3. Overwintering: Dalian Bay oysters and Omi oysters cultured in the north generally have to go through 2 to 3 winter ice periods. Before freezing, an inspection should be conducted, and oysters that may be threatened should be transplanted to deep water to ensure safe wintering. 4. Fattening: 1 to 2 months before harvest, oysters should be moved to excellent fattening farms for fattening to increase production. 5. Prevent human trampling: Beach-sown oysters can only filter water and feed on the beach. Once they fall into the mud, they cannot live normally and suffocate to death. It is strictly forbidden to trample on the beach at will, and management personnel should walk along the ditch when going to the beach. 6. Clearing ditches: Check drainage ditches regularly to see if they are unobstructed. After low tide, try to avoid water accumulation on the beach to prevent oysters from dying due to high water temperature, lurking enemies, and deep floating mud. 7. Pest control: There are many enemies of oysters, which should be removed when turning over rocks. During the peak breeding period of red snails and litchi snails from July to September, diving should be done to catch their broodstock and egg bags. In the season when crabs are active, strengthen management and catch enemies. 8. Wind protection: Typhoons are very destructive to aquaculture facilities, and they also roll up mud and sand to bury the anchors and oysters. Therefore, after a typhoon, timely rescue is required, raft frames should be repaired, and fallen or buried anchors should be supported. (III) Prevention and control of common diseases 1. Larval bacterial ulcer disease: The pathogens are Vibrio anguillarum and Vibrio alginolyticus. This disease may occur during the breeding process of various oysters. After being infected, the floating larvae sink and become fixed, or their activity is reduced, and they suddenly die in large numbers. Prevention and control methods: 1) Keep the water clean; 2) Discard the diseased larvae immediately; 3) Feed the algae without Vibrio contamination; 4) Use filtration, ozone and ultraviolet light to disinfect the water for seedlings alone or in combination; 5) Spray the whole pond with 50-100 grams of compound streptomycin or 10 grams of chloramphenicol per cubic meter of water for 3-5 consecutive days. 2. Perkins disease of oysters: The pathogen is Perkinsus marinus. Perkins disease is one of the most serious diseases of oysters. This disease has a wide geographical distribution. It mainly attacks oysters over one year old. Oyster deaths occur in summer and early autumn (August to September), and then as the weather gets colder and the water temperature drops, the deaths also decrease. The occurrence of epidemics is related to higher water temperatures (30℃) and higher salinity (30×10?3). When the salinity is below 15×10?3 or the water temperature is below 20℃ or above 33℃, oysters will not die even if they are parasitic by Perkins. Chronically infected oysters gradually lose weight, stop growing, and the development of gonads is also hindered. Severely infected oysters die with their shells open, especially when the environmental conditions are unfavorable. Prevention and control methods: 1) Avoid using infected oysters as seed; 2) Before the oyster larvae settle and metamorphose, thoroughly clean the settling, completely remove the old oysters, remove any objects with live oysters attached between the oyster beds, and do not make the oyster beds too dense; 3) When the oysters grow to an appropriate size, harvest them as early as possible to avoid the occurrence of diseases; 4) Oysters raised in low salinity (?15×10?3) sea areas can inhibit the development of diseases.

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Simply put, it is a kind of seafood with high nutritional value, similar to shellfish.