Freshwater pelicans live in the middle and upper layers of water, and they are able to endure low oxygen, grow in groups, and do not eat each other. They can be cultured at high density. For omnivorous fish, can eat a variety of aquatic plants and pool bottom organic debris, aquatic plants, floating flora and fauna. Artificial compound feeds should have high protein content and a reasonable formula.
The growth temperature of freshwater pelicans is 12 to 32 degrees, and the best growth occurs at about 27 degrees. In addition, it can tolerate extremely low dissolved oxygen environments. Through its unique set of emergency respiratory systems, it can survive for hours in water with dissolved oxygen below 0 5 mg/l. Each year from October to December is the incubating period, but the need for electrical conductivity, water level, rainfall and other environmental factors can achieve sexual maturity. A combination of gonadotropins and luteinizing hormones can also be used to promote sex maturation.
For oxytocin, broilers weighing 3-4 kg should be used. Females should be given two injections at intervals of 18 hours and the male dose should be halved. After injecting the oxytocide, the broodstock is placed in a flow-type hatching pond to keep the pool water flowing. It was found that there were estrus chasing and other estrus phenomena, that is, the effect time was reached. The method of insemination with males and females is 1:1. After the sperm eggs are fully mixed, they are continuously tumbling in the incubator. After the fourth day, the digestive tract of the fry is passed through, and the fish is placed in the fry pool to cultivate the “summer†species. . The method of cultivation is according to the requirements of the general hair ponds, feeding with soybeans, and cultivating plankton with fertilizer and water. After 15-20 days, the fry are all up to 3 cm long out of the pond.
Second, aquaculture technology requirements
1. Water quality requirements for aquaculture water The freshwater whitefish grows normally at water temperature of 26.5+4 degrees, PH value of 6-7, dissolved oxygen of 4.1+2 mg/L, and turbidity of 9.7+5 PPM. The water temperature is 28 to 30 degrees, the swimming activity is active, the feeding intensity increases, and the reaction is sensitive. Freshwater whitefish can also grow normally in weakly acidic water (around pH 6.3).
2. Freshwater whitefish can be cultured in ponds either in monoculture or polyculture, or in high density cages or running water.
(1) Single-cultivation pond area of ​​3 to 10 mu, water depth of 25 to 3 meters, and 50 to 70 kg of quicklime dry clearing pond per acre for 10 days before stocking. After the residual poison disappears, the water is released at a depth of 1 meter and base fertilizer 1000 per mu. Kilograms culture water, when the transparency is 20-25 centimeters when stocking. The amount of stocking depends on production design requirements, technical management levels, and feed preparation. The survival rate of stocking is generally calculated at 90%, and the specification for each tail is about 1 kilogram, and the total design output value (kg) is the stocking mantissa.
Feeding management procedures and practices are the same as those for squid and squid farming. The protein content of the artificial-combined pellet feed to be fed should be about 30%, and it should be fed twice a day. The total amount is 8% to 10% of the total weight of the fish, and it will increase or decrease depending on the weather and the feeding conditions of the fish. The feeding of feed is based on the "four definite" principle, that is, qualitative, quantitative, timing and positioning. When the fish body grows to more than 0.5 kg, the feeding amount can be reduced to 2% - 3% of the fish body weight. In addition, it should also pay attention to changes in water quality, water quality should not be too fat, when the transparency of the water body is less than 30 cm, part of the water should be changed. When the water temperature is lower than 20 degrees, the feeding amount should be adjusted.
(2) The polyculture and polyculture not only does not occupy the pool, but also can significantly increase the yield and increase efficiency. The method is to add 30 to 50 white bream fishes in the ponds for puffer fish and puffer fish, and increase the yield by 30-50 kg per mu at the end of the year. Technical management is based on the method of raising squid and carp.
3. Feed Requirements Freshwater fleas have higher requirements on the quality of feed. Freshwater pelicans are omnivorous fish and can eat artificial pellet feeds. They require higher protein content in the feed and the formula should be reasonable. If improperly formulated, their food intake decreased significantly, and they even refused to eat. The freshwater pelicans eat fast, and when they see the feed, they suddenly rush in to eat. After eating, he stays in the dark in the water and rarely moves, so it consumes less energy. Freshwater white pelicans have a relatively large amount of food. Under the condition of a feeding rate of about 7%, the growth rate is fast, and the daily growth rate is 5.7%. When the feeding rate is about 2%, the daily growth rate is 1.64%. When the feeding rate was about 3%, the daily growth rate was 2.09%. During the breeding stage of freshwater fish, the growth rate and feeding rate were positively correlated within a certain range, and the growth rate increased with the increase of feeding.
Third, breeding potential
1. Individuals grow fast, and the population yield is high. Overwintering fish species can produce up to 1,000 pounds per mu in the case of about 1000 mu per mu. The average individuals can reach more than 0.5 kg. In the year of stocking, the animals were up to 200 grams in the same stocking density, and the yield was more than 300 kilograms. Individual growth and colony yields indicate that freshwater ferrets are high-yielding species.
2. Miscellaneous eating habits and high catch rate The freshwater whitefish are dominated by omnivorous feedstuffs. Feeds such as wheat bran, vegetable cakes, bean cakes and rice bran can be used for feeding. Freshwater pelicans are easy to catch. The first online catch rate accounts for more than 90% of the total, and the second network can basically catch it.
3, adaptability, high survival rate of freshwater whitefish suitable for a variety of water culture, the survival rate is generally more than 90%.
First, the biological characteristics of freshwater white turtle body oval, lateral flat; the head is small, mouth in the mouth, the kiss is blunt; positive tail type, bifurcation deep; body height is 2 times the body length, body thickness of 6.5 times . There is a fat fin at the base point of the dorsal fin caudal handle.