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The development of shrimp mantis (2)
Water quality control The purpose of water quality management in aquaculture is to maintain the water temperature, salinity, dissolved oxygen, transparency, water color, and pond biological density in the aquaculture water within the optimal growth requirements for the cultured species to facilitate breeding of the species. The normal growth, to achieve the purpose of high and stable production. Shrimp larvae are typical intertidal organisms and have a strong tolerance to changes in temperature and salinity. However, when prawn puffers are cultured, their water quality changes due to their high density often require water quality management. The daily water quality management work is: record the water temperature, salinity and dissolved oxygen 1 to 2 times a day. Depending on the water quality in the pond, decide whether to change the water properly. Keep dissolved oxygen above 4 mg/l, and transparency is controlled between 30 and 50 cm. In summer, the pool water level should be increased, and as much water as possible should be changed in the open sea to keep the water temperature within 33°C to prevent the water temperature from being too high and affect the growth or death of the shrimp. When the water temperature is higher than 33°C, there is a clear death phenomenon in shrimp. In the winter, the water level should be deepened, and the water temperature should be too low (<5°C) to freeze to death. Although shrimp mane is widely adaptable to salinity, salinity changes should be paid attention to places where salinity changes greatly. During the breeding period, every 10 to 15 days, 210-6 quicklime can be used to improve water quality and sediment quality. It can also increase the calcium in the water and facilitate the shelling and disease prevention of shrimp. Monitoring and management of shrimp growth rate is faster, under normal conditions, its body length can be increased by 0.9 to 1.0 centimeters every ten days. In general, the growth of the body length of mantis shrimp is faster than that of the later period. During the breeding season, the body length of the female individual no longer grows because the energy it uses is used for gonadal development. After the reproductive period, it can continue to grow. According to experiments, under the same conditions, black-spotted shrimp grow faster than shrimp. The growth measurement is usually performed once every 10 days. The sample site is trapped with cage nets. In order to ensure the accuracy of measurement, each measurement sample requires more than 50 samples. For the estimation of the number of shrimp ponds, it is difficult to use simple methods to calculate the number of ponds because they live in burrows. However, it can be calculated based on the amount of ten days of growth and the amount of feeding, combined with the water quality conditions at that time. In the culture of shrimp mantis, daily management work should be done as follows: (1) Check the blockages regularly for damage and remove any debris or dirt hanging on the net. (2) Check the dam for any loopholes or bursts, and repair it if found. (3) Regularly inspect the feeding situation of shrimp shrimp, sample anatomy, and observe the content of stomach contents. (4) Check the situation of bait, predator, and sediment when ebbing or releasing water. (5) Take a sample every 10 days to measure its growth. If the growth of body length reaches 0.9-1.0 cm or more per ten days, the explanation is normal. If this does not meet this requirement, the cause should be ascertained. (6) Observe the drill habits, shelling habits and Other living habits. If it is found that the shrimp do not drill holes during the day, they may be seriously polluted or lack oxygen. (7) Pay attention to weather changes, harbor water quality, etc. If abnormal weather is found, precautions should be taken in time. If red tides and other unclean water are found, it is not advisable to enter the water and enhance oxygenation. After harvesting the shrimp meal to the commercial specifications, it can be sold according to market demand. According to the survey, the market price depends mainly on the individual size of the mantis shrimp, the goodness of the plumpness, and the degree of development of the female gonad (paste). Individuals more than 11 cm in size, good plump shrimp, market sales are smooth; in the breeding season, as long as the female gonad development is good, individuals even smaller (females about 8 cm can be sexually mature), are also popular. Due to the burrowing nature of shrimp oysters, the fishing methods are specific. According to their habits, the following fishing methods are used for culturing prawn oysters: (1) Set net fishing: in the season where the water temperature is 15°C or higher. Fishing with this method is simple and labor-saving, and generally can capture more than 90% of the total. However, this method is only suitable for fishing at low tide in the night, and it is not possible to feed the fish on the night of fishing. Because shrimps have a nocturnal activity and prey on habits, they will inhabit after drilling. The specific method is as follows: first, the cover net is placed in the groove of the water gate, and the gate is opened at the time of ebbing at night, and the pool water is released, and the shrimp gills will flow downstream into the net. After the pool water is drained, the water is re-introduced at high tide, and it is recaptured the next evening. This is repeated. (2) Earthworm net fishing: In the middle and late stages of shrimp rearing, this method should be used for inter-docking or for catching large market hours. If the breeding ponds do not feed bait at the end of the day, it is better to put bait fishing in the ground nets. Dilong Network is a trap-type fixed network, T-shaped. It has many entrances and a sac net, and there are inverted meshes at each entrance. Shrimp pods are difficult to get out of the mouth and the sac nets are arrested. During the operation, the nets were placed in the pond and the shrimps rushed into the net at night when they were out of the hole due to feeding. The next morning, just pour out from the bladder net. A certain number of ground dragon nets are placed for harvesting depending on the amount of demand and area. (3) Dry-land catch: After catching the shrimp larvae that have been caught by the above two methods or the shrimps that have been trapped in winter due to the low water temperature, they have to catch it with a dry pool. The specific method is: first put the pool water dry or pat dry, you can see the bottom of the pool shrimp cave. The U-shaped shrimp mantle cave has two near-circular outlets, one large and one small. Use your feet to get in from the big hole and forcefully squat a few times. The shrimp worms climb out of the small hole. Due to the high density of the cultured animals, the caves often communicated with each other; or when they were overwinter, the caves became "Y" shaped, and the method of using the pedals was not effective. It had to be picked up by other tools. This hole-by-hole capture basically catches the shrimp in the net pool. Mixed other types of fish and shrimp swimming, but at the same time capture, can be used Zhangtao net fishing; if not harvested, should not put dry pool water, should be collected several times, or choose several fishing methods mixed.