Breeding of tilapia

Tilapia is a kind of tropical fish, which has the advantages of wide adaptability, strong reproduction, miscellaneous eating habits, strong disease resistance, high feed utilization rate, fast growth and delicious meat, and has become a widely cultivated freshwater fish. Especially the Nile tilapia (Oreochromis aurea× Oreochromis niloticus) is welcomed by farmers because of its high male rate, rapid population growth and high yield. Maoming City, Guangdong Province, made full use of local geographical advantages and natural conditions to vigorously develop onion tilapia breeding industry and achieved remarkable results. Tilapia farming in Maoming City has reached a certain scale. In 2003, the polyculture area of tilapia in Dan Yanghe reached 380,000 mu, and the output was 130029 tons, which was 44.73% higher than that of 89,845 tons in 2006, accounting for 1/3 of the same variety output in the whole province. Tilapia farming output ranks first in the province. According to the current pond culture technology and experience, and referring to the relevant technical data of Nile tilapia, the operating rules of high-yield culture technology of Nile tilapia were formulated.

1 pond conditions

The suitable area is 1. 1, and the pond area with water depth of 5 ~ 25mu is the best. The water depth of fingerling pond is 1.0 ~ 1.8m, the water depth of commercial fishpond is 2.5 ~ 3.0m, and the height of pond ridge is 35 ~ 35~55cm higher than the water surface.

1.2 The fish pond is rectangular with the best east-west direction, which is beneficial to ventilation and sunshine. The length-width ratio of the fish pond is 1.5 ~ 3.0: 1.

1.3 The bottom of the pond should be flat, easy to pull the net, loam or sandy loam, and the sludge at the bottom of the pond should be controlled within 14 ~ 20 cm, with good water retention and no water leakage.

1.4 the water source is mainly surface water, and the following factors should be considered for the water source conditions of pond culture:

1) The water quality shall meet the requirements of the Fishery Water Quality Standard GB 1 1607 ~ 89;

2) The water quantity should meet the needs of fishery production, especially in May ~165438+10, which is the main season of fishery production. There is enough water to enter the pond for water injection and water exchange, and the water exchange quantity in the production season is generally required to be once10 ~ 20%;

3) Each pond has its own relatively independent water intake and drainage system;

4) The transparency of the pool water is about 30 cm.

Ensure the power supply of 1.5 and the supporting power supply of fishing machines, and require the power supply of commercial fish ponds to reach 1kW/ mu. If conditions permit, a diesel generator with sufficient power is required as its own power supply. Each pond is equipped with 1 ~ 3 sets of 3kW impellers or waterwheel aerators according to the area and stocking quantity, and fish ponds with smaller area and shallow water depth can be equipped with 1 ~ 3 kW water jet aerators. In ponds using hard pellet feed, each pond can be equipped with 1 ~ 2 automatic bait feeder. Can't self-flow irrigation and drainage, and equipped with adequate water injection and drainage equipment.

2 Preparation before stocking

2. 1 The pond should be cleaned and trimmed to avoid water leakage.

2.2 Remove silt once a year to ensure that the thickness of silt is controlled at 14 ~ 20cm.

2.3 pond cleaning and disinfection

2.3. 1 dry pond cleaning Dry pond cleaning means that after finishing the fish pond, only 8 ~ 12 cm of water is left at the bottom of the pond, and the pond is cleaned with 4 ~ 5 kg of tea bran or 50 ~ 80 kg of quicklime. Return to water after 3 days of exposure. The injected water is filtered with a 40-60 mesh net to remove impurities.

2.3.2 The bleaching powder for pool cleaning with water contains about 30% of available chlorine, and the bleaching powder 13.5kg is used for each mu of water depth 1m, that is, 20g is used for each cubic meter of water to make the water concentration 20ppm, or quicklime 100 ~ 150kg is used.

2.4 After applying base fertilizer to the backwater of the pond, apply 250kg of organic livestock manure per mu to cultivate water quality. Organic livestock manure should be fermented and decomposed, disinfected with 1% ~ 2% lime, and planted after 7 days of fertilization.

3. Source, quality and specification requirements of cultured fish species

3. 1 Selection of fish source The stocking species must come from the production site approved by the commercial department and have the aquatic seedling production license.

3.2 Stocking fish species requires that the stocked fish species are pure in variety, neat in specifications (the individual difference in weight is within 10%), strong in physique and free from injuries. All-male tilapia species mainly choose the hybrid F 1 of pure Nile tilapia ♂ and pure Nile tilapia ♀ (onion fish), F 1 from Wu Guoyu, Taiwan Province and other hybrid F 1 tilapia. The male fish rate is over 92%, the fishing rate is over 85%, and the growth is fast.

4 fry cultivation

4. 1 culture pond The culture pond covers an area of 2 ~ 3 mu, with a water depth of more than 1.5m, and is abundant in water and convenient to enter and exit. Thoroughly clean and disinfect the seedlings before releasing them, and expose them to the sun for 3 ~ 5 days.

4.2 Fresh water should be injected 7 ~ 8 days before the seedlings are released. Irrigation needs to be filtered through a 40 ~ 60 mesh net to remove impurities. After the water depth is 80cm, apply chemical fertilizer (organic fertilizer, chemical fertilizer or green manure, etc.). ), and release the fish species after the plankton proliferates. After stocking 10, the water depth increased to1.5m.

4.3 When the fry are released by temperature, the temperature difference between the water temperature for transporting the fry and the water in the culture pond.

No more than plus or minus 2℃. The aquaculture water temperature is kept above 22℃.

4.4 fry density: put 80 ~ 65438+10,000 fry in the same batch per mu, and put enough fry at one time.

4.5 During the first 3 days after the fish fry are managed in the pond, they are mainly fed with blood paddles of livestock and poultry or cooked bean flour; After 17 days, feed cooked soybean flour, rice bran, yellow flour and low-grade flour.

4.6 fry out of the pond and cultured separately

1) After 20 days of cultivation, fry can generally grow to 3 ~ 5 cm, and then fish can be cultivated in ponds and ponds.

2) Out of the pool for separate culture. Stop feeding the day before leaving the pool. The net should be smooth and delicate, and the net should be opened at 9: 00 a.m. on sunny days to avoid opening the net under the scorching sun. The operation is brisk, "no water", that is, crossing the pond at once.

5 fingerling cultivation

5. 1 The culture pond and fry pond shall be cleaned and disinfected before sowing. The injected water is filtered with a 40 ~ 60 mesh net to remove impurities. Apply 250 kilograms of pig manure or other livestock manure per mu to cultivate fertilizer and water. Organic livestock manure should be fermented and decomposed, and disinfected with 1% ~ 2% lime. The water quality is beautiful and the transparency is about 25cm. The seedlings should be released after 7 days. The aquaculture water depth is above1.5m.

5.2 stocking density: 0.8 ~ 65438+ 3cm or 5cm per mu with 0.5 million fry of the same specification.

5.3 After feeding and releasing the seedlings, feed the compound pellet feed containing 32% crude protein, and the pellet size is 1.5 ~ 2mm. Feed twice a day, 8-9 am and 5-6 pm, and the daily feeding amount is 7-8% of the fish weight.

5.4 After 20 days of cultivation, the fish will grow into fingerlings, with a total length of10 ~1cm and a weight of about 25 ~ 50g, which can be cultured in ponds.

5.5 Disinfection of fry and fingerling Drugs and methods for fish disinfection mainly include the following:

1) salt: 2%~4% concentration, soaking for 5 ~ 10 min.

2) Bleaching powder: the concentration is 10 ppm ~ 20 ppm, and the soaking time is about 10 minute.

3) Penicillin: 80000 units /50L, soaked in water for 5 ~ 10 min.

5.6 Stop feeding the day before tidying the pond. Select 12 fine purse seine and cage with smooth eyes for round-up and sorting, and open the net at 9: 00 am on sunny days to avoid working in the scorching sun. Sorting with bamboo screen and stocking in different specifications.

6 pond adult fish culture

6. 1 After the pond is filled with base fertilizer, apply 250kg organic livestock manure per mu to cultivate water quality. Organic livestock manure should be fermented and decomposed, disinfected with 1% ~ 2% lime, and planted after 7 days.

6.2 Stocking density adopts high-density feeding. 800 ~ 1500 tilapia fingerlings are stocked at one time, while 35 silver carp, 40 bighead carp and 0/5 bighead carp are stocked per mu.

6.3 Feeding management

6.3. 1 Feed with complete compound hard pellet feed, and the protein content of the feed shall not be lower than 28%. Processing quality standard of hard granule compound feed;

1) The powder content of hard pellet feed is less than 3%.

2) The particle diameter of hard pellet feed is 20% of the effective diameter of fish, and the diameter-length ratio is 1: 1.5 ~ 2.0.

3) Feed should not go bad, with good physical properties and stable nutrients.

4) Feed processing uniformity and feed raw material granularity meet the quality requirements of aquatic feed processing.

5) Hard pellet feed has good stability and palatability. Tilapia likes to eat soft feed.

6.3.2 The feeding amount should be regularly and quantitatively fed according to the weather, water temperature, dissolved oxygen and water quality. Feed twice a day, 8-9 am and 5-6 pm. When feeding artificially, it should be fed at a fixed point in the pond. The daily feeding amount shall be based on daily storage × daily growth rate (reference value 1.2%)× feed coefficient (experience value 1.7), and the feeding amount of the next day shall be based on the previous day.

6.3.3 Feeding mode The feeding machine can save 6-8% feed compared with manual feeding, and the fish can eat evenly and have the same individual size. Therefore, feed machine is popularized to feed hard pellet feed. Each pond shall be equipped with at least 1 bait feeder.

6.4 Water quality management Water quality management is one of the key technologies for pond culture to achieve high yield and implement healthy culture. The main adjustment measures are as follows:

1) Keep the water quality alive, cool and tender. Through fertilization, controlling drainage and water injection, using quicklime and other measures to adjust the water quality, the transparency of the pool water is 25 ~ 35 cm.

2) Keep 2) the 2)pH value at 7 ~ 8.0. Quicklime, organic fertilizer and chlorine preparation can be used for water quality regulation. Controlling the pH value of pond water with quicklime is very effective for most acidic ponds in Maoming City. Spraying aqueous solution of quicklime once a month per mu, each time is generally 7.5 ~ 15 kg per mu per meter.

3) Dissolved oxygen shall be above 3 mg/L for 24 hours and not less than 5 mg/L for 16 hours. The main technical measures are as follows: by improving water quality, controlling the suitable fertility of pool water and adopting biological oxygenation; Inject fresh water frequently to replenish water-soluble oxygen in the pool; Prevent water quality from being too fat, remove silt, etc. So as to reduce the consumption of dissolved oxygen by oxygen consumption factors.

4) aerator equipment: equipped with impeller aerator according to the standard of 0.3 kW per mu. In general, it is opened twice a day, from 2 noon to 2 noon and from 2 am to 4 am.

5) Prevent the phenomenon of "old water" and "turning water". The main measures are as follows: first, replenish fresh water in time or start the aerator to prevent the water quality from deteriorating; The second is to sprinkle quicklime with a dosage of 25 kg per mu, pour wine into the slurry and add new water to the original water level; Old water can be treated with copper sulfate for 2 ~ 3 days, and then adjusted with quicklime.

6.5 culture out of the pool

1) Individual fish can be sold from pond to pond as commercial fish.

2) Stop feeding the day before sale.

3) When fishing and selling, how much to sell and how much to make, so as to avoid making too much damage to the fish.

Prevention and treatment of fish diseases Tilapia is prone to parasitic or bacterial gill rot, ulcer and frostbite in the low temperature environment of pool water. To prevent drastic changes in water temperature, oral sulfanilamide prevention; Ascites (abdominal distension) and red fin desquamation will occur in high temperature pond aquaculture. You can spray quicklime 15ppm and take antibiotics orally.