Rainbow trout is named for its brownish-red markings on both sides of its body. Rainbow trout has the characteristics of delicious meat, rich nutrition, less thorn meat, artificial reproduction and easy operation, and is one of the four high-quality freshwater aquaculture species promoted by the United Nations Food and Agriculture Organization to the world. Cultured rainbow trout in a flowing water environment can produce 30,000 to 35,000 kilograms of fresh fish per acre of water. The economic benefits are extremely significant.
Rainbow trout is a cold-water fish, its normal growth water temperature is 1 °C ~ 24 °C, the optimum growth temperature is 14 °C ~ 16 °C; water oxygen requirements in more than 5 mg / l; pH value of 7 ~ 8.
Rainbow trout broodstock is generally mature between 2 and 3 years of age, and females spawn once a year, spawning 1000 to 3000 capsules each time. Rainbow trout broodstock begin breeding in December each year.
1. Breeding fish. The broodstock requires gravel bottoms with a water depth of 1.5 meters and a flow rate of 0.05 flows (5 litres per 100 square meters per second). Stocking densities range from 1 to 3 tails per square meter, with a ratio of 1:1 for males to females. Rainbow trout is afraid of light, and the daily light time is controlled under 12 hours. During the whole year's cultivation, the feed formulation changes with the gonadal development stage, and usually animal feed accounts for 20% to 30% of the total amount, and it should be increased to 50% to 60% before egg collection, before harvesting, and after harvesting. The feed amount is 0.5% to 2% of body weight.
2. Oviposition insemination. Females use caudal fins to dig pits in slow-flowing shallow water to build nests, and their body color is gradually dark. The vents are red and prominent, and the abdomen is large and soft. At this time, if there is a sense of free egg, the eggs are lightly pressed. , indicating that the female fish is mature. Males have darker body color, rougher surfaces, and softer around excretory holes. White semen can be seen on the lightly pressed fish belly, indicating that the male fish is mature. The general water temperature begins to pick up eggs at 1°C~11°C, 5°C~9°C is the time of spawning, and the method of extruding eggs is used. The specific approach is as follows: One person grabs the female fish with its head up and its abdomen is aligned with the ovary. One person gently presses the cleaned basin along the direction of the genital hole to lightly press the ovary at the trailing edge, and the eggs flow into the basin. Then, using the same method, male sperm were squeezed into a pot, stirred with feathers for 30 seconds, and then the two were brought into full contact with a small amount of fresh water. After a little stirring, the mixture was allowed to stand for 2 minutes before adding a large amount of fresh water and standing for 4 hours. The fertilized eggs can be poured into trays for hatching, and the entire process must be shaded.
3. Incubation method. A 200 cm 40 cm 37 cm sink is made of wood or plastic. The size of the hatchery is 33 cm, 33 cm and 1.6 cm. The egg hatching tray is placed in a sink. The upper hatching tray covers an empty plate and presses a weight to prevent drifting. Shade in the hatchery. The suitable water temperature for hatching is 7°C~13°C, the optimum water temperature is 8°C~10°C, and the water flow rate is 10 liters to 20 liters per minute. Note that in the entire incubation process, the dead eggs are removed in time. The eggs are disinfected once a week for 30 minutes with 1% formalin or 2% saline solution.
Rainbow trout is a cold-water fish, its normal growth water temperature is 1 °C ~ 24 °C, the optimum growth temperature is 14 °C ~ 16 °C; water oxygen requirements in more than 5 mg / l; pH value of 7 ~ 8.
Rainbow trout broodstock is generally mature between 2 and 3 years of age, and females spawn once a year, spawning 1000 to 3000 capsules each time. Rainbow trout broodstock begin breeding in December each year.
1. Breeding fish. The broodstock requires gravel bottoms with a water depth of 1.5 meters and a flow rate of 0.05 flows (5 litres per 100 square meters per second). Stocking densities range from 1 to 3 tails per square meter, with a ratio of 1:1 for males to females. Rainbow trout is afraid of light, and the daily light time is controlled under 12 hours. During the whole year's cultivation, the feed formulation changes with the gonadal development stage, and usually animal feed accounts for 20% to 30% of the total amount, and it should be increased to 50% to 60% before egg collection, before harvesting, and after harvesting. The feed amount is 0.5% to 2% of body weight.
2. Oviposition insemination. Females use caudal fins to dig pits in slow-flowing shallow water to build nests, and their body color is gradually dark. The vents are red and prominent, and the abdomen is large and soft. At this time, if there is a sense of free egg, the eggs are lightly pressed. , indicating that the female fish is mature. Males have darker body color, rougher surfaces, and softer around excretory holes. White semen can be seen on the lightly pressed fish belly, indicating that the male fish is mature. The general water temperature begins to pick up eggs at 1°C~11°C, 5°C~9°C is the time of spawning, and the method of extruding eggs is used. The specific approach is as follows: One person grabs the female fish with its head up and its abdomen is aligned with the ovary. One person gently presses the cleaned basin along the direction of the genital hole to lightly press the ovary at the trailing edge, and the eggs flow into the basin. Then, using the same method, male sperm were squeezed into a pot, stirred with feathers for 30 seconds, and then the two were brought into full contact with a small amount of fresh water. After a little stirring, the mixture was allowed to stand for 2 minutes before adding a large amount of fresh water and standing for 4 hours. The fertilized eggs can be poured into trays for hatching, and the entire process must be shaded.
3. Incubation method. A 200 cm 40 cm 37 cm sink is made of wood or plastic. The size of the hatchery is 33 cm, 33 cm and 1.6 cm. The egg hatching tray is placed in a sink. The upper hatching tray covers an empty plate and presses a weight to prevent drifting. Shade in the hatchery. The suitable water temperature for hatching is 7°C~13°C, the optimum water temperature is 8°C~10°C, and the water flow rate is 10 liters to 20 liters per minute. Note that in the entire incubation process, the dead eggs are removed in time. The eggs are disinfected once a week for 30 minutes with 1% formalin or 2% saline solution.