Tilapia has the advantages of wide appetite, low oxygen tolerance, rapid growth, low incidence, and strong reproductive ability. At present, aquaculture is widespread in China, and it is the main breeding species for many local fishermen and farms. Tilapia is a tropical fish. It has special requirements for aquaculture environment and feeding and management, especially in the four critical periods of broodstock breeding, fry breeding, adult fish breeding and wintering conservation.
Tilapia adult breeding methods mainly include pond breeding, water aquaculture, cage culture, rice paddy farming and marine aquaculture. The following mainly introduces freshwater aquaculture.
I. Pond culture
1. Pond conditions Farming sites should be selected in a place sheltered from wind, sunny water, abundant water, fresh water, no pollution, quiet and convenient transportation. Pond area is 3 mu to 5 mu, water depth is 1.5 to 2 meters, pond sediment thickness is 20 Centimeter - 30 cm. Each pond is equipped with a 1.5 kW impeller aerator.
2. Clear pond fertilization Before stocking, clear ponds should be disinfected. Generally in mid-April, fresh lime 75 kg to 100 kg per acre clear pond, 7 days later, add water to 1 meter deep, then apply 300 kg to 400 kg per acre of manure, can put a small amount of annatto or Hongping .
3. Stocking of fish species When the water temperature rises every spring and stabilizes above 15Â°C, the winter seedlings are released. The main pond raises generally 1,500 to 3,000 tails per acre of stocking species, and 40 to 70 tails of polycultured cockroaches and squid species to control water quality. When mixed with other fish, they can stock 200 to 500 tails per acre.
4. Feed the tilapia into the aquaculture water for 2 days to 3 days before feeding. Tilapia has a wide range of feeding habits. Under the condition of artificial feeding, it can feed various feeds, such as wheat, corn, and rice cakes. The protein content in the feed should be 32% to 35%, and the daily feed volume should be 3% to 5% of the total fish body weight. When the individual specifications grow to about 200 grams, the amount of feed can be adjusted to 2% of the total fish body weight and ensure that the protein content in the feed is between 27% and 29%. When individuals reached about 300 grams, tilapia entered the fastest growing period, with daily feeds maintained at 1% to 2% of fish's body weight and protein content of feeds above 35%. Feed 2 times a day at 8 am to 9 am and 3 pm to 4 pm.
5. Day-to-day management should pay attention to day and night patrol ponds.
(1) Measure water temperature and temperature every morning, evening and evening, measure pH value once a week, and measure transparency twice. In the morning and at night, each patrol pond is once.
(2) After the fish species is under the pond, keep the pool water dark brown with a transparency of 25 cm to 30 cm. Fertilizers are generally applied once a week, with 150 kg to 200 kg of livestock manure applied per acre. When the weather is clear and the transparency of the water body is greater than 30 cm, the amount of fertilizer can be appropriately increased. When the water quality is too fat, the fertilizer should be reduced or stopped, and new water should be injected. In the hot season, generally change the water 1 to 2 times a week, each time to replace the pool of water 20% to 30%.
(3) Adhere to healthy culture, operate according to procedures to prevent fish diseases. Seeds were soaked with 5% saline or 0.1 mg potassium permanganate solution per tank for 10 minutes to 15 minutes. Every 10 days to 15 days, 15kg to 20kg of calcined water per acre is sprayed on the whole pond, and the pH of the treated pond water is slightly alkaline. Biological agents are used to improve the microbial structure of the pond and improve the water quality. An aerator is opened when the dissolved oxygen is low and the fish has a slight floating head.
Second, paddy field fish, rice symbiosis, can obtain double harvest. When paddy fields raise tilapia, scientific feeding should be taken care of.
1. After the rice field field project is completed, two weeks before stocking, use 75 kg to 100 kg of calcareous water per acre to disperse in the fish ditch and field plots, and then dip the ditch and the bottom of the field one time to make the lime slurry. Mix well with the sludge. Fertilizer was applied to the fermented livestock manure for 1 week prior to planting. The amount of 200 kg per mu was used to cultivate natural food in water.
2. The stocking time is generally about 5 days after the rice is transplanted, and it is stocked when the seedlings return to green. In order to increase the growth period of fish, some places will put fish into the fish ditch in mid-May, and it is also a good idea to put the fish into the fish ditch after the seedlings return to green and then open the fish ditch and fish into the fields.
3. Stocking methods Fish species should be selected for their robust physique, strong mobility, no injuries, and tidy fish species. The stocking density should be reasonable. In general, tilapia fingerlings ranging in size from 5 cm to 6 cm can be placed in 200 to 300 tails per mu, and 150 to 200 tails such as grass carp and squid can be used. The specific amount of stocking can be flexibly controlled according to conditions of rice fields, water quality environment, drainage and irrigation conditions and management levels.
4. The fish species for stocking operations should be disinfected before entering the pool. Generally, the fish body is bathed with 3% to 5% salt water for 5 minutes to 10 minutes. The time for fish release should be in the morning or evening on a sunny day. Do not put fish on a rainy day or in a sunny day.
5. Feeding and Fertilizing Rice Paddy Farming Rodeo generally does not feed bait and grows by ingesting natural food. However, natural food in paddy fields is limited, and it is appropriate to feed a portion of the bait to accelerate its growth and increase production. Feeding twice a day, the amount of feed can be controlled in the bait 2 hours after eating is appropriate. The paddy fields of fish farming have no special requirements on the base fertilizer and farmyard manure. With urea, ammonium sulfate and other topdressing, it should be a small number of times, apply a half a block of land, should not be directly in the fish ditch fertilization.
Third, cage culture Tilapia in the cage can be single, main or collocation. Fish species should be large in size, and the box size is generally 10g to 50g. When the amount of dissolved oxygen is more than 3 mg per liter, the stocking density is 3 kg to 20 kg per cubic meter.
Fourth, flow-through culture of tilapia is one of the main targets of current high-density culture or â€œfactoryâ€ culture. The aquaculture pond should not be too large, and raising fish is generally suitable for 30 m2 to 50 m2. The amount of dissolved oxygen in the pool is maintained at more than 3 mg per liter. Intensive farming requires feeding a nutritious compound feed, and the protein content of the feed should be about 30%. It is fed 5 to 6 times a day, and the amount fed is 2.5% to 3% of the fish's body weight.
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