1 Biology of New Prawns (1) Morphological Characteristics New shrimps are yellowish to brown in color, brown or red in swimming feet, and lavender and light yellow ring spots in between. Tail dark brown. The shell is thick, with many short hairs on the body except for the ridges and edges. The abdomen is smooth and glabrous on both sides of the abdomen. Many black spots are scattered on the body surface. The forehead male is straight, sharp-knife-shaped, and the female is slightly curved upwards, reaching to the end of the third antennae of the first antennae shank, and the upper edge has 6-9 teeth. The posterior ridge of the forehead is prominent and extends to the back of the cephalothorax. The back of the abdomen has 1 to 6 knots with a smooth longitudinal ridge at the center of the abdomen, and the back ridges are tall and sharp at the back. There is a small thorn at the end of the 6th abdomen, and 1 sting at the posterior horn. Tail saving is 13 times the length of the 6th section, with no side edge thorns. Step 5 is full of thorns.
(2) Ecological habits New shrimps are shallow sea shrimps, which are widely distributed in the coastal waters south of the Shandong Peninsula in China. The water layer is also widely distributed. It is distributed in shallow sea areas of 140m and water depth is 20 to 50m. The sea area is denser. Often inhabit sand, mud, sand bottom of the sea area. The adaptability to environmental changes is strong, and the water temperature to be adapted is 10 to 37°C. When the weather is cold or transparent, it hides in the bottom and reaches a depth of 8 to 10m. The temperature period is often lurking in the bottom, exposing only two eyes and tentacles. Predation at dusk and more night activities. Adapting to a wide range of salinity, not only can grow in seawater, but also can grow well in freshwater. The tolerance to low dissolved oxygen was stronger than that of shrimp. The asphyxiation point of the shrimp was 021 mg/L, the larva was 163 mg/L, and the adult shrimp was 061–03 mg/L. It can normally live in pH 7-9 water bodies.
(3) Fresh-edged shrimp is a food-eating shrimp with predation of benthic organisms, basal zooplankton and swimming creatures. Its food composition mainly includes polychaete, perforated, amphipoda and bivalves. , gastropods, Ostracoda, copepods, swimming shrimp, etc. There was a significant monthly change in food intensity, which was the lowest in March and the highest in May-August, with the highest in June-July and beginning to decline in August. The intensity of day and night changes in the intensity of ingestion is the lowest in the day, and it begins to rise at dusk and continues to increase at night and is highest in the morning.
(4) Breeding habits The amount of new prawn sexual maturity ranges from 10 to 16 cm, and the smallest mature individual is 8 cm long and weighs 7 g. The proportion of sexual maturity increases with body length. Every year from the third to the tenth of October, mature shrimps can be seen. In sexually mature females, the ovary extends from the front of the breastplate to the end of the abdomen. The ovary can be seen through the carapace. The color change is similar to that of the prawns. It is transparent---yellow---light orange - dark green--- Red-green, the ovary is divided into anterior, middle and posterior leaves. The amount of new shrimp eggs for the wholesale breeding mature, 10 ~ 14cm broodstock, the amount of eggs for 80,000 to 450,000 / tail, fertilized egg diameter 02 ~ 031mm. The fertilized eggs hatched at the water temperature of 27 to 30°C and suitable salinity for 10 to 18 hours after embryonic development. The nauplii developed into juvenile larvae after 1 to 2 days, and the larvae developed to the larval rearing larva about 6 days later. After 12 days, they developed into prawns, and they were reared for 8 to 10 days and the body length was about 07 cm.
2 Freshwater pond rearing for new shrimp (1) Pond conditions and preparation pond area should not be too large, 013 ~ 02hm2 is appropriate, pool depth is about 15 ~ 2m, slope is slightly larger, slope ratio is 1:25 or so, is conducive to feeding And shrimp foraging. The bottom of the pool is flat, and the new shrimp has a habit of dipping sand according to the amount of the knife. The bottom of the pond retains about 10 cm of mud. Around the bottom of the pond, a ring ditch is excavated, with a width of 1m and a depth of 05m. The ring ditch is 2m away from the edge of the pond and a central ditch is opened in the middle, with a width of 4m and a depth of 05m. The pond is well-watered, the water is fresh and pollution-free, and there is an independent and effective drainage system. Before the stocking of shrimps, the clearing pond must be disinfected to remove wild fish and other predators. About 20 days before the stocking of shrimps, the whole pool was used for disinfecting with the calcined pulp. When disinfected, the pool slope and the pool bottom should be spilled evenly. The amount of quicklime was 100-150kg/0067hm2. 7 days before the stocking of shrimps, 150 kg/0067 hm2 of organic fertilizers that had been fermented by decomposed fermentation were placed, mainly livestock and poultry, followed by water injection of 50 cm. When the water was injected, the water injection port was filtered with a 40-mesh sieve to prevent enemy pests from entering the shrimp ponds. After about 7 days, a large number of zooplankton, such as Cladocera, Copepoda, and Rotifera, appeared in the pond. This is the best time for shrimp ponds.
(2) For shrimp stocking, the new shrimp is originally living in seawater. The artificial seedlings are also carried out in high salinity environments. Generally, the proportion of seawater at the time of emergence is about 1020. It must be domesticated after being transferred to freshwater. (referred to as desalination) process. It can be said that whether or not the new amount of shrimp is fresh or aquaculture is successful depends on the desalination of shrimp seedlings. Therefore, only the desalination of good shrimp can be used for stocking. The desalination of shrimp seedlings is a gradual process that cannot be overemphasized. The proportion of shrimp from the 1020 seawater descends in order: 1020-→1015-→1010-→1007-→1005-→1003-→1001-→10005-→1000. The salinity gradient is small and the salinity gradient is small. The survival rate of seedlings is high, whereas the survival rate of prawn seedlings with salinity gradient is low. Desalination is a process that gradually reduces salinity. In general, the longer the survival rate is, the better the survival rate is. It may take 10 to 15 days. The length of the seedlings during desalination may increase from 04cm to about 07cm. According to Zhu Wenxiang (1999), the specific method of desalination is to start the 7-day storage period, and gradually increase the number of unfinished fish seedlings that have been cultivated or introduced since the beginning of the transition from seawater to sea in different places. The proportion of seawater accounts for 1018 to 1020. The metamorphosed larvae complete the metamorphosis process. During storage, the light and density should be controlled, and the water temperature should be adjusted to about 26 to 30°C, and continuous aeration should be maintained. Freshwater is added daily after stocking. Each time the amount of water is about 10% of the total amount of water, the salinity of the pool water is gradually reduced until the water is full, then it is put into the side to keep the water quality good and prevent floating heads. 1d before the stocking of shrimp, with 2 ~ 3cm green shrimp seedlings test the water 5 ~ 6h, and then stocking the amount of new shrimp seedlings. Stocking 04-04-inch shrimp seedlings without intermediate breeding, stocking capacity 80,000 to 100,000 tails/0067 hm 2; if intensively reared, specifications are 1 to 15 cm, stocking amount is 50,000 to 60,000/0067 hm2; Specifications are 15cm or more and stocking capacity is 40,000 to 50,000 tails/0067 hm2. The specific amount of stocking should also be based on shrimp pond conditions and technical conditions. The stocked shrimps require smooth, crystal-clear appearance, well-proportioned specifications, robust physique, and strong bouncing power.
3 Feeding and management (1) Feeding and management Pre-breeding (3cm in length), that is, 1 month of shrimp seedlings mainly depends on planktonic plankton as feed or supplemented with a small amount of fine-grained food, and they are fed with artificial diet one month later ( Macrobrachium (feedstock) is the main feed, and the daily feed amount is 4% to 6% of the shrimp weight in the pond. During the growing season, there are some conditions where the broken snails and other miscellaneous fish are added. The amount of bait should be flexibly adjusted according to the season, water temperature, climate, and water quality, and adjusted in time. If the water temperature is 25 ~ 30 °C, the knife amount of new shrimp feed strongly, in order to ensure its rapid growth, should seize the opportunity to feed more feed, and in the feed properly added 03% ~ 05% multivitamin and bone meal and the like Additives to ensure their growth and nutritional needs. Feeding methods are fed along four weeks, feeding 1/3 of the daily feeding amount during the day and feeding 2/3 in the evening, and increasing the investment in the middle of the growing season.
(2) When the water quality management is in the lower pool, the water depth is controlled at about 60cm and maintained for about 10 days. After that, water is added 1 to 2 times every 7 days, each time water is added 10-20cm, and the maximum water depth is 15-16m. After the water is full of ponds, let go of the bottom water regularly, choose the best water release in the sunny morning, let go of 50~60cm bottom water, let the sun shine into the water body as deep as possible, make the whole water body become oxygen-enriched area, accelerate the shrimp shell, facilitate Its growth. Pay attention to the quality of fertilized fertilizer and mechanical oxygenation. Fertilization should be regulated according to the degree of water thinning. The control of water color is yellow-green or dark brown, and the transparency is controlled at 30-35cm. The amount of fresh shrimp in the shrimp pond is higher than that of other shrimps, so the improvement of the bottom quality is very important. The use of quick lime (10~15kg/0067hm2) in small amounts from time to time has certain effect on the improvement of water quality and sediment quality.
(3) Routine management Check the eating situation on a daily basis and adjust the amount of feeding in time according to the inspection. Carefully observe the phenomenon of lack of oxygen floating head, especially in the event of sudden changes in the weather, such as sultry or under the shower, the shrimp easily floating head, should adjust the amount of feeding in time, rushed into the new water or start aerator. Frequently inspect the inlet and outlet net bags and prevent the escape of nets from being damaged, and prevent wild fish from entering and shrimp from fleeing. At the same time, do a good job in disease prevention and treatment to prevent disease and timely treatment. Prevention and control of shrimp disease, mainly using strong chlorine fine Quanchiposa disinfectant water and food additives to prevent.
(4) The harvest time of the new shrimp for harvesting is mainly determined by the growth status and market demand of adult shrimp. Generally, it is cultured in a freshwater pond for 80 to 100 days, and it can reach a commercial size of 7 to 10 cm long. Method of catching.
(5) In the cage, the cage is usually dropped in the evening and the cage is collected in the morning on the second day. This type of harvesting method will allow the shrimp to be listed one after another.
(6) Pulling nets and shrimps to catch shrimp with a net in a shrimp pond with a flat bottom, the catch rate is usually 50% to 70%. According to the habit of strong ability of shrimps at dusk or before dawn, and considering that they can catch up with the morning market in time, selling a good price, generally shrimps are caught at 20-22 in the evening, and the effect is better.
(7) Dry ponds for catching shrimp When the water temperature drops below 15°C, shrimps basically stop feeding and growing. After catching by the above two methods, they should actively catch and market them according to market demand. The fishing method should be pumping or discharging water. Pond fishing.
3 NEW OBJECTIVES OF NEW-GRADE Fresh-sheltered prawn Freshwater prawn has a high technical level and therefore has a high risk of breeding. However, it has created a gratifying situation. In the future, with the continuous improvement and development of breeding technology, it should be said that In a certain period of time, the new shrimp will have a better development and good prospects. However, we must keep in mind the experience and lessons of some varieties of breeding, and do not blindly develop it in order to avoid creating a vicious cycle of developing one variety and one species. We must actively and steadily guide and promote freshwater aquaculture of shrimp. , And continue to explore, summarize and improve during the development, especially in the aspects of shrimp seedling desalination, water quality management, ecological environment and other aspects to strengthen technical research, obtain mature experience, and achieve further development in the increasingly mature.
The new penaeus Metapenaeusensis deMan is a species of Decapoda, Natantia, Pcnaeidae, and Metapenaeus. It is commonly known as the base prawn and is highly regarded by consumers for its thin shell body and tender meat. Favor. The amount of fresh shrimp has been maricultured for many years, but freshwater aquaculture was successfully tested in the middle and late 1980s. Many domestic production units have conducted experimental aquaculture and have achieved good results. Bao Weikong et al. (1999) A good result of 12075kg/0067hm2.