Culture techniques of tilapia

Abstract: tilapia is a kind of small and medium-sized fish, its shape and individual size are similar to crucian carp, and its fins are like mandarin fish. The main species cultivated in China are Nile tilapia, Aulia tilapia, Mozambican tilapia and hybrid offspring of various combinations, which have high culture value. Let's take a look at the culture technology of tilapia.

Tilapia is a kind of small and medium-sized fish, its shape and individual size are similar to crucian carp, and its fins are like mandarin fish. The main breeds of tilapia in China are Nile tilapia, Aulia tilapia, Mozambican tilapia and hybrid offspring of various combinations. It has high culture value, so let's take a look at the culture technology of tilapia.

The living habits of tilapia

1. Miscellaneous eating habits: tilapia is a plant-based omnivorous fish. For tilapia in the pond, most of the contents in the digestive tract are organic detritus and other plant feed (such as aquatic plants, commercial feed, etc.), followed by phytoplankton, zooplankton and a small number of benthos.

2. Hypoxia tolerance: tilapia has a strong tolerance to hypoxia, the asphyxiation point is 0.07-0.23 mg / L, and tilapia can still live and reproduce when the dissolved oxygen in water is 1.6 mg / L. When the dissolved oxygen in water is more than 3 mg / L, the growth is not affected.

3. Intolerant to low and high temperature: the survival temperature range of tilapia is 15-35 ℃. Tilapia is dormant when the water temperature is below 15 ℃. The highest critical temperature of tilapia is about 40-41 ℃, the optimum growth temperature is 28-32 ℃, and the reproduction temperature of tilapia is above 20 ℃.

4. Strong fecundity: tilapia has the advantages of early sexual maturity, short spawning cycle, oral hatching, low reproductive conditions and natural reproduction in static water with large water area.

Reproduction techniques of Tilapia

The suitable water temperature for the reproduction of tilapia is 22-23 ℃, which usually lays eggs naturally after the middle of May. In order to grab the season and make full use of light, heat and bait resources, in order to increase the culture yield, artificial warming, strengthening cultivation and early spring propagation must be adopted to make tilapia lay eggs and hatch seedlings in the middle of April. The specific measures are as follows.

1. Selection and cultivation of parent fish: choose parent fish with good maturity to be put into the spawning pond in the middle of March to strengthen cultivation, and the spawning pond can choose the overwintering pond. Generally, 6 parent fish are released in every square meter spawning pond, with a male-to-female ratio of 2 ∶ 1 or 3 ∶ 1, and the water should be changed regularly at the same time.

2. Warming and feeding management: the water temperature in the pond should be controlled above 23 ℃, and the water quality should be fertilized, live and cool. The feeding amount can be determined according to the water temperature, water quality and the growth of fish. In general, the daily feeding amount of the static pool is 2% of the body weight of the fish, and the running pool is 3%. At the same time, we should often observe the activity of fish and the degree of gonadal development, and make good records.

3. Spawning: there is an obvious difference in body color between male and female tilapia. Estrous males swim by the pool, looking for a place to make a nest. The shape of the nest is pot-shaped, with a diameter of 30cm and a depth of about 10cm. After the nest is completed, the male fish tease the female fish from time to time and intercept the female fish into the nest for pairing. When the water temperature reaches 22-23 ℃, the female can lay eggs. When spawning, the abdomen of the female fish is close to the bottom of the nest, and the male fish guards the nest. After spawning, the female fish immediately sucks the eggs into the entrance, and the mandibular tympanic process is cystic. The male fish immediately enter the nest to ejaculate, and the female fish sucks the semen into the mouth with water. The egg is fertilized in the mouth.

4. Hatching: the fertilized eggs of tilapia hatch in the mouth of the female and turn with the breathing of the female, which not only gets the protection of the mother, but also has a good hatching environment. When the water temperature is about 30 ℃, it takes about 4-5 days to hatch the fry, and it takes about 7 days when the water temperature is 25 ℃.

Culture techniques of tilapia

1. Pond preparation: the area should be 3mura and 5 mu, and the bottom is flat. Ten days before stocking, the pond was disinfected by sprinkling the whole pond with 70 kilograms of quicklime per mu. 2After 3 days, 100kg farm manure such as chicken manure and pig manure are applied per mu, water is injected to one meter, and the water color changes to tea brown or oil green, and then fish fry can be released.

2. Fish stocking and collocation: in the south, when the air temperature rises steadily (the water temperature is above 18C), the fry will be released in the middle and late April. Each mu is put into the specification of 3.0-3.5cm Onixia fish 2000ml 2500, large size silver carp 40, silver carp 30, can also be matched with a small amount of carp, crucian carp and so on.

3. Pre-feeding: after releasing the mermaid fry, stir the soaked peanut cake or rapeseed cake evenly, sprinkle it to the center along the edge of the pond, and feed it at the rate of 1.5 Mu per day. After a month of breeding, the fry can grow to about 10 centimeters and weigh 10 Murray 12 grams.

4. Management in the middle and later stages

① feed feed: the growth temperature of tilapia is 222232 C, and the appetite is exuberant. The feeding range should be wide, and all fish species should be fed evenly as much as possible. Its feed has rapeseed cake, bran cake, wheat bran, peanut cake, bean cake and so on, it is best to mix. Tilapia was fed with full-price formula feed twice a day, 9: 00 in the morning and 4: 00 in the afternoon. Daily bait intake: weight 10 Mel 20 g, 5 Mel 7% mai 20 Mel 50 g, 4 mi 6% Rue 50 Lue 100 g, 3 mi 5% Jue 100 Lue 200 g, 2 Mel 4% 200 g or more, which is about 2% of the body weight of the fish.

② water quality control: water can be gradually added to 1.5m from mid-May to June, July and August is the high temperature season, adding water to about 1.8m, it is best to change the water once a week if possible, to keep the water fresh and prevent flooding.

Prevention and treatment of ③ fish disease: adhere to the principle of giving priority to prevention and paying equal attention to prevention and control. Fish can be soaked in 4% salt water for 10 minutes for 15 minutes before release. Fish disease occurs frequently from May to September. Bleaching powder 1ppm or quicklime 20kg / mu can be sprinkled in the whole pond every half a month. When there are signs of fish disease, antibiotics and vitamin baits can be used for 3-5 days.