Scallop Shrimp Pool Keeping Techniques

The sea-scallop seedling maintenance rate of the bay scallops is generally less than 10%, but in the shrimp ponds, the seedling conservation rate is generally above 1.0%, and even the higher ones can reach 40% or more. Due to different management and methods, the seedling maintenance rate is very poor. Great disparity. According to the production and test conditions in recent years, several technical points that should be noted for the preservation of seedlings in the bay scallops are described below. 1. Pond Condition The pond is better with sandy bottom, followed by rock reefs, with poor sand quality, and poor mud bottom quality. It should be able to maintain a water level of about 1.0m below the bottom of the pool. The shrimp ponds in the north all have annular gutters, and the water level in the gutters can be maintained above 1.3m. After harvesting shrimps a year ago, it is best to turn the bottom of the pool to the bottom of the pond. Sprinkle lime 50 to 100 kg per acre evenly to improve the bottom quality; install 50 to 60 mesh nylon screens at the inlet. 2. Fertilizer Before the juveniles are out of the pond, the shrimps have been stocked for a long time. The residual bait of the shrimps and the excretion of the shrimps, together with the consumption of the shrimps by the zooplankton, can achieve the goal of water and fertilizer. It is still relatively large. Apply 1ppm of nitrogen fertilizer every 2 days or even 2 to 3 times. Where fertilizer and water are more difficult, it is recommended to fertilize it once a day for 5 consecutive days. Basic requirements for fertilizer and water can be achieved. Good fat water can increase the growth rate of scallops, and the survival rate and seedling maintenance rate also increase. Generally, the transparency of the pool water is about 40cm, the water color is yellow-brown, yellow-green, and the food predominant species are Chaetoceros, Diamond-shaped algae, Skeletonema, Cylindrotheca, Chlorella. If there is too much dinoflagellate, it should be large in time. Change water or change the pond. 3. Juveniles out of the pool At present, the bay scallop out of the pool size is generally controlled at 250μm or so, to do the seedling bag screen should be used 80 goals, the net bag size to 25cm40cm ~ 30cm50cm is appropriate, the net bag is too small, the effect is poor, bagging With a density of 2 to 30,000 capsules/bag, a mesh or brown string must be added to the mesh bag to increase the adhesion matrix and to meet the growing demand of juveniles. A hard nylon net is also added to support the seedlings. In order to increase the environment inside the bag, the surface area of ​​the seedling bag is also increased, and the exchange capacity of the water body inside and outside the bag is enhanced. The floating raft should be set in the ring ditch. The raft should be about 20m long. The two ends should be fixed with wooden stakes. The buoyancy should be denser and evenly set. The seedling bag should be hung in the low light water layer of 30-40 centimeters. Each string of 4 to 6 bags, hanging spacing 50cm, each string under a 0.7 ~ 1kg of falling stone, the Department of buoyancy should be floating surface 1/3 or more. 4. Brush bag and bag hanging bag. Do not wash mesh bags within 5 days to prevent larvae from leaking from the mesh. During the holding period, the daily growth of the shell is generally about 1.0 μm, so the general shell height can reach 300 μm after 5 days, while the 80 mesh nylon mesh has an aperture of 198 μm, and the hypotenuse of the aperture is 280 μm, so the bag can be brushed without worry. Leaving baby boy. Brush bag is best to use a large tube brush or long hair hard brush, one to wash the mud on the bag completely clean; the second is to plug the debris mesh hole to improve the exchange of water inside and outside the seedling bag, the traditional The soft brush used light brush, light wash, it is difficult to brush through the mesh, this is the shrimp pond seedling operation is too careful, resulting in poor water exchange within the seedling bag, bait and dissolved oxygen difficult to reach the scallop larvae The main reason for the corresponding reduction in the seedling maintenance rate is the demand. Brushing the seedling bags must be done once a day. Many units are used once a day for 3 days. This is absolutely negligible. Since the mesh holes are too small, the pool is free from wind and waves and it is easy to plug the mesh. After about 13 days of storage in the 80-mesh bag, it should be poured into a 60-mesh bag. The mesh size of the 60-mesh sieve is 258 μm, and the length of the mesh is 365 μm. The scallop larval shell height is more than 360 μm. Each bag can hold about 10,000 capsules; after being raised for 10 days, the larvae of scallops are already over 500 μm, and they should be poured into a 40-mesh bag in time, about 5,000 bags per bag. All kinds of bags must be made of hard nylon mesh bags. And add a certain amount of attachment groups. When using a 60-mesh bag, you can brush the bag once every two days, but you have to hit the bag once a day. When using a 40-mesh bag, you can smash the bag once a day. You can not brush the bag. 5. Pool water management Shrimp pool water change, from the third day of juveniles into the pool, once a day early, changing the amount of water to 10% is appropriate, in the middle and late period, about 20% is appropriate. Changing water can not only prevent water quality from aging, maintain relatively stable water temperature, but also form water flow and promote the exchange of water in seedling bags. According to the weather conditions, in the rainy days, the water level of the pond should be increased as much as possible, and the seedling bags should be reduced to prevent the mutation of surface water pool salinity from causing the juveniles to adapt or even die. In the first 3 days of seedling separation, pool water exchange should be strengthened, and the amount of water exchanged can be more than 30%, so that the environmental conditions of the pool water and the water environment of the natural sea area are close to each other, so as to increase the adaptability of juveniles when they go to sea. Improve the rate of farming into the sea. 6. When the juvenile shell is up to 1mm, the juvenile shell should be brushed into the seedling device in a timely manner in the water with a soft brush from the attachment base. The water in the container is changed with the brush. Sub-seedlings generally use a 30-mesh bag, each bag containing about 2000-3000 grains. The sub-seedlings are usually in June, and the temperature is relatively high. Sun-seeds should be erected or separated as soon as possible.

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