Shellfish oyster farming

(I) Culture methods

1. In order to cultivate oysters, choose oyster-type breeding grounds where the trend is smooth, food is abundant, wind and waves are calm, and water depth is more than 4 meters. Oysters near the river should choose the estuary near the lower salinity; Dalian Bay should choose oysters away from the estuary, the sea area with higher salinity; Pacific oysters and pleated oysters in between. There are two main ways to develop:

(1) Sling culture: It is suitable for oysters with shells as the anchoring base. There are two ways to cultivate them: First, the shells holding the seedlings are connected in series with ropes, and the middle is separated by bamboo tubes of about 10 cm. Hanging on the truss; Second, the fixed shell with a seedling caught in a 3 to 3.5 cm diameter polyethylene rope twisting joints, every 10 cm clip 1 shell, hanging on the floating raft. Generally 2 to 3 meters long per rope. You can also use the rubber tires to raise the seedlings.

(2) Net cage culture: using scallop cage culture. The seedlings with no anchorage or the seedlings anchored on the shells are placed in a scallop cage together with shells, and they are raised on floating rafts. The oyster-type raises general stocking seedlings to be 100,000 grains per 667 square meters, and shells are used as seedling harvesters, and can raise about 10,000 shells per 667 square meters. The seedlings are stocked from May and June and harvested at the end of the year. The output can reach more than 5,000 kg per 667 square meters.

2. Beach farming

(1) Site selection: The inner bay should be small, smooth and non-polluting. The sandy bottom should be sand or mud sand beach. The tidal area should be selected in the lower part of the middle tide area and near the low tide area.

(2) Seeding season: It is generally appropriate to broadcast seedlings from mid-March to mid-April. Production can be seeded at the latest by the middle of May.

(3) Seeding method

Dry tide sowing seedlings: It is the seedlings that bloom on the beach after dry tide. Before sowing seedlings, the beach surface should be leveled, or it should be built into a loquat-shaped base and then propagated. Dry tidal seedlings should try to grasp the high tide immediately after sowing seedlings, in order to shorten the seedlings' open time and avoid seedlings when exposed to sunlight at noon.

With water broadcast seedlings: After the high tide, soaring by boat. Before the seedlings are planted, the beach surface is to be striped, bamboo sticks, wooden poles, etc. are used as signs. After the high tide, the seedlings shall be sprinkled on the boat with pickaxe. With water sowing seedlings can not directly observe the distribution of seedlings, often resulting in uneven seeding. The density of seedlings should be determined according to the quality of the beach and the fatness of the water. Outstanding beach has about 120,000 seedlings per 667 square meters, about 100,000 medium-sized seedlings, and generally 600,000 to 80,000 seeds.

3. Clam and shrimp polyculture

(1) Shrimp tank selection: shrimp ponds of mixed oysters, the sediment is suitable for mud or mud sand, and the average water exchange rate should be about 50% on a water depth of 1.3 meters or more. The transparency in the early stage should be controlled within 40 to 50 centimeters. Later control in 50 ~ 60 cm.

(2) Site preparation: Before stocking, the seedlings should be thoroughly dredged and the bottom of the playing oyster seedlings should be leveled and compacted with bulldozers and other tools. The shape is slightly convex, slightly higher than the surrounding floor, which can prevent seedlings from sprouting. Shen was buried by silt to death.

(3) Seeding: Under the premise of ensuring the normal stocking density of prawn, the amount of oyster cultivars should be about 30,000 grains per 667 square meters. Seeding time should be selected in early April. Seed seedlings should have a shell length of 2 cm or more. The seedlings were stressed evenly and avoided the low ditch and feeding area of ​​the ditch and ditch. The sown area accounted for 1/4 to 1/3 of the bottom area of ​​the pool.

4. Cast stone breeding: used as a stone for oyster harvesters, this time becomes a oyster breeding equipment. The pleated oysters with shorter growing period can be cultivated on the spot in the nursery, and the Olong oysters with longer growth period should be cultivated in the breeding field. Cultivation methods include three types: sky star, plum blossom, and determinant.

(1) The Sky Star: The stone is miscellaneously placed.

(2) Plum: Generally 5 to 6 pieces of vermiculite are in one group.

(3) Determinant: Line width 0.5 to 1 meters, row spacing is 0.6 to 1.5 meters. Deep-water cultures can be managed without seedlings until they are harvested.

5. Bamboo culture: The bamboo seedlings are sparsely cultured in situ using bamboo seedlings. When growing, there are two ways to arrange bamboo:

(1) Straight line: Take 150~179 pieces of bamboo into rows, 3~5 meters in length, or insert 100~120 pieces of bamboo into rows, leaving 2~3 neutral positions in the middle of the row for smooth flow Water flow.

(2) Inclined insertion: Take 23~26 branch bamboo into 1 pile. The bottom is 45-60 centimeters wide, the top is 33-36 centimeters wide, and the distance between pile and stack is 20-25 centimeters. A row consists of 5 to 6 piles, with a distance of 2.5 meters between the row and row. Each 667 square meters can be inserted 8000 ~ 10000 branches bamboo.

6. Bridge farming: After harvesting seedlings using a bridge seedling method, the stone is rearranged to evacuate the density and cultivate. Generally 6 to 7 pieces of stone are 1 group, and the group is connected to 1 group by stone bars. The distance between the groups is 50-60 cm, and the distance between the columns is 1-2 meters. During cultivating, the dark side and the dark side of the stone should be interchanged so that both oysters grow evenly.

7. Standing stone culture: After using the vertical stone picking method to collect seedlings in the mid-tide area, as long as the seedling volume is appropriate, it can be allowed to grow naturally without any management until it is harvested. This method is mainly used for the breeding of pleated oysters.

8. Grid farming: This breeding method is based on the water depth of 2 to 4 meters, the waves calm, after the bait is set in the inner bay fixed shelf, the shelf is set with the same type of mining seedlings. The seedlings are mostly fixed in series with shells, cement tiles, etc. Each string is 1 to 1.5 meters long and 0.5 to 1 meters apart. The density of the culture should not be too high to prevent bottoming out so as to prevent certain benthic predators from invading.

(B) Management during development

1. Turnstone (moving stone): It is to move the position of meteorites. Turning stones can prevent oysters from being suffocated by sludge, and they can stir floating sludge to increase the nutritive salt of the feed and promote the growth of oysters. Turning stone is usually 2 or 3 times during general growth.

2. Flood control: During the rainy season, precautions must be taken to prevent the influx of floodwaters, or dikes and floods along dikes, or to move oysters to deep-sea areas with high salinity for conservation.

3. Wintering: Dalian Bay oysters and Omi oysters farmed in the north generally have to undergo 2 to 3 winter icing periods. Check the oysters that may be threatened before they are frozen and transplant them into deep water to make them safe for the winter.

4. Finishing: 1 to 2 months before harvest, the oysters are transferred to a finishing farm for fattening to increase yield.

5. Prevention of human trampling: beach oysters can only filter and feed on the beach. Once trapped in the mud, they cannot normally live and suffocate. It is forbidden to trample on the beach, and managers should follow the channel when they go to the beach.

6. To clear the channel: always check the drainage channel is open, after the ebb tide beach surface should be as far as possible without water, to the temperature of the water is too high, enemy predicament, muddy mud, etc. cause oysters to die.

7. Injury: Oysters have many predators and should be removed when combined with turningstones. During the period from July to September when Rhodospirillifolia and Periwinkles bloom, they should dive to capture their pro-shellfish and egg bags. During the season when crabs are active, strengthen management and capture predators.

8. Wind protection: The typhoon is very destructive to aquaculture facilities. It is also reported that there are mud sand buried fixtures and oysters. Therefore, after the typhoon, it is necessary to rescue the typhoon in time, repair the trusses, and support the fallen or buried anchors.

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