I. Pond and fish stocking (I) Pond conditions 1. The area of ​​the pond and the depth of the fish pond should be a little wider, so that the range of activities of the fish is wide, and the pool water can often be blown by the wind, which will increase the oxygen content of the pool water and enable continuous convection of the surface and lower water. Promote the full decomposition of organic matter. Generally 3-6 acres of area is more suitable for feeding management and capture. The annual water level of the pond water for farmed clams and barracudas must be maintained at 1.5-2 m, so that the water temperature is not easy to change and the water quality is easily maintained. The bottom of the pond should have a certain slope, so that the water temperature of the pond will be different, so that it is easy for the fish to choose to swim in moderately warm water. 2. Pond ponds and barracuda ponds are usually made of muddy sand. This type of soil is loose and moderately strong, and has strong water retention capacity. The organic matter in the pool is easily decomposed, and the upper layer is easy to grow “oil sludgeâ€, which contains a large amount of bentonite. Algae, the main bait for cockroaches and barracudas. The bottom of the pool should have a certain thickness of fertilizer layer (10-20cm) to maintain the fertility of the pond. However, when a large amount of sludge is accumulated in the pool, it should be excavated. 3. Water sources and water quality in ponds, barracudas can adapt to living in seawater and pure fresh water, but brackish water is the most suitable. It has the effect of promoting the growth of barnyard grass and barracuda. The water source should be sufficient, and seawater and freshwater injection should be convenient. Especially in the case of high-density intensive culture, frequent water injection can increase the amount of dissolved oxygen in the water, avoid floating heads, and avoid deterioration of water quality and “pan-poolingâ€. The water for fish farming should not contain substances that are toxic to fish. The pH should be appropriate, and more nutrients should be dissolved. (2) The ponds can be trimmed into ponds before they can enter the winter. After exposure and lyophilization, the harmful organisms hidden in the sludge are more likely to freeze. The method of clearing the pond is the same as the cultivation pond. The second year of water intake, fertilizer and water before the drug clearing pool. (3) Base fertilizer and water-based base fertilizer should strive for early application and adequate use. Early application can breed natural food as soon as possible for fish to eat. At the same time, after the pond water becomes fat, due to the increase of suspended matter (plankton and organic debris) in the water, it can absorb more solar thermal energy and increase the water temperature, which relatively increases the growth period of the fish. Basal fertilizer should be given at one time. The dosage depends on the pond's fatness and the type of fertilizer, generally 250-350kg of manure per acre. Shiji Fei is usually carried out after the winter fish ponds are cleaned and before watering. Fertilizer can be spread over the bottom of the pool and exposed to sunlight for several days. After initial decomposition, the bottom mud can be turned and the sun can be sprayed for a few days to inject new water. This method is used to increase the weight of sediment. Basal fertilizer can also be applied after water injection to make it water. When water is injected, it should be filtered with a dense net. (d) Fish stocking 1. The fish species specifications of the squid are laid earlier and have a long growth period. The southern coastal provinces generally directly develop summer fish species into food fish. Barracuda generally choose 10-12cm spring fish species to develop food fish. 2. Restocking time should be sooner rather than later. In the cold climate in the north, after the winter, the barracuda fish species can be stocked when the water temperature stabilizes above 5-6°C after melting ice. In Fujian and Guangdong provinces, carp fingerlings can be stocked in ponds in March and March, while Zhejiang is required to enter ponds in April-May. This is related to the sooner or later of the eel fry phase. 3. Stocking Density (1) Single-cultivation: The single-cultivation of barracuda is still in the experimental stage. The barracuda aquaculture has little benefit, but it can raise 2-3 fish. The density control in Jiangsu is: the requirement for the production of 150-200kg per mu can be used to put 500 seedlings in the year (summer flower), 350 fishes in the second year, and 300 fishes in the third year. According to Zhejiang's experience, a single rearing pond can store 3.3cm seedlings per acre with 4000 tails and 6.7cm seedlings with 1,500 tails. Israel’s saltwater freshwater left-handed fish ponds, with 0.1ha (equal to 15 acres per hectare), put 700-1000 fingerlings on the water surface. In Hong Kong, 1,500 fish species are laid on every 0.1ha of water. (2) Polyculture: Currently, the mix proportion and stocking density of barracuda species in polyculture ponds are extremely inconsistent. All kinds of fish polyculture can form beneficial relationships that promote each other, but if they are improperly matched, they will inhibit fishes. Grow. According to the experience of freshwater fish ponds in Tianjin, the proportion of barracuda spring fish species mixed with grass, alfalfa, alfalfa, cockroach and cockroach is generally 10%, then it can grow to 0.5-0.75kg, and even grow to 1kg when diluted. . In the Shantou area of ​​Guangdong, China, the polyculture of the catfish is the main body, and several hundred to 1,000 fish species have been stocked per acre of fish ponds, some as many as 4,000. Jiangsu Provincial Institute of Fisheries and Ganyu County Fish Farm. In 1979, polyculture of shrimp and barracuda was carried out in a 3.3-acre pond. The average number of shrimp seedlings per acre was 6060, and 179 fish species were used for spring flowers. Some summer flowers and three years of fish, 91kg per mu per year, and 63.65kg per day. In Guangdong, polyculture with shrimp as the main body, with Chinese prawns, Penaeus sinensis, Newly-supplied prawns, and new prawns in close proximity were mixed with common carp. Generally, 20-30 prills of carp were about 3cm long per acre. When the shrimp production is not affected, the production of carp is increased. Israel has polycultured carp, alfalfa and tilapia in brackish water, with a density of 500-900 per hectare carp, 1,200 common carp, and 1050 tilapia. Second, aquaculture management (a) Fertilizer, barracuda bait can be used to cultivate natural food-based feed, and add some artificial feed. In China, more organic fertilizers are used. In addition to applying base fertilizers before fish stocks are stocked, during the aquaculture process, fertilizers should be topdressed in appropriate amounts according to the water color and transparency of the ponds in order to stabilize the fat and increase the natural food of the fish. Inorganic fertilizers are widely used in fish ponds in foreign countries. It has been reported that the application of phosphate in saltwater fish ponds can increase the yield of carp by 96.0-166.7%. (II) The feeding habit of the feeding bait and barracuda under the conditions of artificial breeding shows a strong plasticity, which can be widely used according to the principle of “local materialsâ€. Such as various kinds of oil cakes, rice bran, sweets, distiller's grains, bean dregs and other food baits, wild vegetables, Moss, leaves, melons and other green, roughage (to be processed), clams, clams, leeches, small miscellaneous fish, Silkworm cockles, fish meal and other animal foods are desirable. In order to improve the palatability and nutritional value of foods, appropriate processing can be done, mixed feeding, or artificial feeding can be made. In terms of feeding technology, we can learn the “three look†(see the weather, look at the water color, watch the fish activity and feeding) and the “four determinations†(quality, quantity, timing, positioning) summarized by the fishermen in the long-term production practice. ) Feeding principle, flexible use. The “definition†in “four orders†is a material condition, and the other three are all technical problems in feeding. The specific contents are: 1. The qualitative requirements for the quality of bait are refined and fresh. In addition to being able to meet the dietary requirements of fish at different stages of development as far as possible, “precision†should be fed with diets rich in nutrients, and should also work hard from the fine processing of the bait. The "fresh" is the requirement that the bait be kept fresh and clean, rotten, and susceptible to fish diseases. 2. Positioning Regardless of the size of the fish's stocking density in the pool, the bait is best placed in a feeding device set at a fixed location for fish to feed. Submerged bait (such as bean cake) should be placed on the food table. The food table is generally made of four corners supporting the lu seat and fixed in the water layer. The dining area is about 1-2 square meters, and it is best to be located on the north bank of the pond, where there is no wind in the sunny area, the water is open, and there are few people and livestock. The setting depth of the food table depends on the type of fish, the size and season of the fish, and the water temperature. It is also possible to set up a food court in a place where the bottom of the pool is hard and sludge-free, without a food table. Positioning feeding is not only convenient for checking feeding conditions, but also conducive to the removal of food residue, food disinfection, etc., to ensure that the pool fish to eat and drink. 3. Quantitative quantification is based on the size of the fish, and puts the bait in a controlled manner in different seasons and times. According to the fish plan, the fish body weight gain plan and various feed bait factors, plan the amount of feed throughout the year. According to the water temperature and the growth period of the fish, the monthly feeding amount is planned. It is also necessary to plan for the daily amount of bait, and be flexible in accordance with the specific conditions, so as to effectively achieve "three look." 4. The regular feeding season should start early and end at the end of the day to extend the growth period of the fish. In the growing period, the number of feedings per day should be considered in conjunction with the amount of bait. The principle is “a small number of timesâ€. The bait should be eaten quickly after it is dropped, the new food is not connected, and the bait is wasted, affecting food hygiene. General rare pool (hundreds to hundreds of thousands per mu) can be fed once a day and in the afternoon, and the amount of feed should be 3-4 hours. Concentrated pools (thousands to tens of thousands per acre), depending on the density, increase the number of feedings appropriately. (III) Daily management In addition to fertilization and feeding, routine management tasks include: The ponds that feed food fish in the patrol ponds are more prone to the phenomenon of lack of oxygen floating heads and pans because of their higher stocking densities, especially in the high-temperature season from July to September. When the weather is normal, the floating head usually occurs before and after the dawn, or occurs in the middle of the night. Generally after the sunrise (7-8 o'clock), the fish go on. The rainy days sometimes occur in the first half of the night. The weather is hot in summer and autumn, and water pollution can be added. Caused serious fish head floating, even "pan-pool" phenomenon, causing a lot of death, so it should be frequent patrol pond. In the summer and autumn, at least two times a day, inspect the ponds and see if there are any diseased fish and floating heads. In the afternoon, check the fish feeding situation and observe whether there are signs of floating heads and be aware of them. When the weather suddenly changes, it should stay up all night. Combined with the determination of dissolved oxygen, it was found that hypoxia should be immediately replaced by water, oxygenation and other measures. 2. Although heatstroke and barracudas are warm-water fish, it is difficult to adapt when the water temperature rises above 35-38°C during the summer season. Especially shallow ponds should pay attention. Therefore, in addition to maintaining proper water depth and timely changing of water, it is possible to put shamisen shade in the corner of the pond, which can occupy 1/4 to 1/5 of the area of ​​the pond. Some of the common predators in enemy fish and barracuda ponds are crabs, fish and birds. For example, thick crabs, squid, mudskippers, spear-tailed gobies, terns, and herons are very harmful to farmed fish and must be guarded against. In addition to carefully clearing the pool, strict control of the water inlet and outlet, fishing can also be used to fish harm. Crabs can be trapped in the evening light. The bird can be used as a bird killer. (4) The time for harvesting food fish harvesting should be considered comprehensively depending on the water temperature, requirements and market conditions. The ability of pupae and pike to withstand low temperature is stronger than that of prawns. Barracuda in northern China is still a good time for growth in October. Therefore, the time for harvesting in a single pool can be extended until the end of October, when the temperature of the water drops, and the fish are not very active. Can put water into the net. Mixed ponds can be harvested with collocations.
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