The suitable water temperature for tilapia reproduction is 22-23°C, and natural spawning usually occurs after mid-May. In order to grab the season and make full use of light, heat, and bait resources to increase aquaculture production, it is necessary to artificially increase the temperature, intensify cultivation, and early spring propagation so that tilapia can be hatched and hatched in mid-April. The specific measures are as follows.
1. Broodstock selection and cultivation
The broodstock with good maturity was selected to be placed in the spawning pool in mid-March to strengthen the cultivation. The wintering pool can be used for the spawning pool. Normally, 6 broodstock are stocked per square meter of spawning pool, with a ratio of 2:1 or 3:1, while changing water regularly.
2. Warming and feeding management
The water temperature in the pool should be controlled at 23°C or higher. The water quality should be fat, live and cool. The amount of feed can depend on the water temperature, water quality, and the growth of the fish. In the general cistern, the daily feeding amount is 2% of the fish body weight, and the flow pool is 3%. At the same time, we must constantly observe the activity of fish and the degree of gonadal development, and make every record.
3. Spawning
The body color of tilapia females and males is obviously different. The estrus male swims around the pool and seeks locations to make nests. The shape of the nest is pot-shaped, with a diameter of 30-40 cm and a depth of about 10 cm. After the nest is completed, the males will seduce from the female group and intercept the females into the nest. When the water temperature reaches 22-23°C, females can lay eggs. At the time of spawning, the abdomen of the female fish is close to the bottom of the burrow, and the male fish is guarded by the nest. After the females lay eggs, the female eggs are sucked into the mouth immediately, and the mandibular protrusion is saccular. The male fish immediately enters the nest and the females suck the semen into the mouth with water. The egg is fertilized in the mouth.
4. Incubation
The tilapia fertilized eggs hatch in the female's mouth and turn with the female's breath, which protects the mother and has a good incubation environment. When the water temperature is around 30°C, the fry hatches about 4-5 days; at 25°C, it takes about 7 days.
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