Suitable pond ponds are suitable for east-west rectangular structure, sandy bottom or hard bottom, water depth is above 1.5 meters, salinity is below 35 ,, and there is no pollution in the external seawater; before the pond enters water, it is necessary to completely clear the bottom of the pool Contamination, and adequate exposure; prohibit the stocking of large-sized benthic fish or other species that require large amounts of feed in ponds for conservation of seedlings to prevent contamination of pool water.
Pay attention to do a good job of water quality regulation Scallops into the pool 10 days -15 days into the water 60 cm -80 cm, apply fertilizer and water, nitrogen fertilizer amount per cubic meter of water 3.5 grams, depending on the application of phosphate fertilizer, depending on the circumstances, generally 1 / 1 nitrogen fertilizer Around 10, the bait density is controlled at 50,000-200,000/ml. Gradually increase the pool water to the highest water level from 4 days to 5 days before entering the seedlings. Transparency of 70 cm to 80 cm is appropriate. If the transparency is too high and the temperature is high before and after noon, inorganic fertilizers shall be topdressed in a timely manner. If the transparency is too small and the bait density is too large, the number of water changes should be increased a few days before the scallop seedlings enter the pond, so that the water can be cleared without being thin, and the fertilizer is not old. Before releasing the seedlings, it is necessary to strictly monitor the physical and chemical indicators of the water quality of the seedling nursery pool to ensure that all indicators are within the prescribed range; after the seedlings are transplanted, the daily water exchange volume should reach more than 20%. If the water color changes, the water quality is aging, which is the occurrence of the seashell seedlings. The omens of death, at this time should completely change the water or change the pool in time.
When selecting high-quality juvenile vaccines, it is necessary to carefully select juvenile seedlings with uniform specifications, firm attachment, appropriate density, and less than 15 days of attachment time. The water quality of the nursery is basically the same as that of the seedling pool. Generally, the water temperature of the pond is stable at 13°C and can be kept in the pool to protect the seedlings; the larval rearing temperature must not be higher than the prescribed water temperature. The cultivation of monocytic algae in nursery should be reasonable, and the supply should be sufficient to ensure uniform specifications and healthy growth.
Appropriately increase the juveniles' delivery specifications. Normal juveniles' delivery specifications are 500 micron, and the specifications are increased to 700 micron to 800 micron, which can greatly increase the seedling preservation rate.
Strictly loaded and transported seedlings, bagging personnel must perform pre-post technical training, be skilled in operation, shorten the bagging time as much as possible, and use a polyethylene thread to attach the attachment base to the bag opening to avoid multi-layer folding and backlog friction. Cause injury. Suitable for transporting seedlings in the early morning or evening. Pay attention to sealing, moisturizing, and cooling during transportation. Try to shorten the transportation time.
A reasonable determination of the seedling density can generally use no more than 100 million juveniles of 500 micron water per mu and no more than 30,000 seedlings per bag. With the increase of the size of juvenile shipments, the number of seedlings will be appropriately reduced.
Use double mesh bags and circular mesh bags to keep seedlings
When the double-layer net bags are kept out of the warehouse, the juveniles are loaded into a 20 mesh-30 mesh polyethylene mesh bag, and the cover is 40 mesh-60 mesh mesh bags. About 10 days after entering the pool, the bag seedlings in the bag have grown up, the outer bag is removed, and the juveniles on the outside of the inner bag are put into a 40-mesh net bag for raising, which not only removes the attachment but also releases the shellfish. seedling. Double-layer net bag seedling maintenance rate can reach more than 30%.
Round mesh bag seedling round net bag is made of 20 mesh and 40 mesh polyethylene mesh sewn into a cylindrical shape, bottom diameter 200mm, height 280mm-300mm, built-in a cylindrical plastic frame, diameter 185mm, height 60 Mm. The advantages of the circular mesh bag are many. Under the support of the plastic frame, it has a large space for seedling preservation and smooth water flow, which allows the bellies to move freely, increase the probability of ingestion, and avoid the death of juveniles caused by accumulation, friction, and mutual bite, etc. The net bag conservation rate can be as high as 40%.
Strengthen the daily supervision measures to fully tighten the floating raft, properly increase the seedling bag falling stone, reduce net bag swing, adhere to the tour pool, prevent mesh bag twisting and broken frame, broken rope, stone off phenomenon, as long as the mesh plug is not serious, Do not brush the net. When you need to wash, you can put it in the water to reduce the damage of the shellfish seedlings.
Timely sub-seedling into the sea to raise the seedlings pond nursery time should not be too long, the general conservation seedlings 20 days -25 days, juveniles specifications reach about 3 mm, you can split the seedlings into the sea, into the intermediate breeding stage, the sea time should be selected in the calm weather to avoid Dry and direct sunlight, it is better to do it in the morning and evening.
Ffp2 Kn95 Face Mask,Ppf2 Protective Cup Mask,Kn95 Protective Cup Mask,Ppf2 Protective Fold Flat Mask
Jiangmen anjian biotechnology co. LTD , https://www.jmanjianmask.com