I. Biological Characteristics
Golden trout is a genus of salmonids in the Salmonidae family. Homozygous combination of pure golden trout hair eye egg size of 4.0 to 6.0 millimeters, because there is a diameter of about 1.5 to 2.5 millimeters of rose-red oil ball inside the egg and was bright red. Golden trout is similar in size to rainbow trout, with a golden, orange or yellowish body, a red colored band on the side of the body and a rose-red eye. When fed diets containing carotenoids, the body color is more brilliant and the flesh is orange-red. Golden color is a purely dominant trait. Golden trout like to live in cool and high dissolved oxygen waters with pH 6.5-7.5, and weakly alkaline water is more suitable for its growth. The upper limit of normal growth temperature is 20℃, the optimal growth temperature is 12～18℃, the farther away from 18℃, the slower the growth, more than 22℃, the mortality rate increases, and all of them die in 25℃ in less than a few days. There is no obvious lower temperature limit for growth, as long as there is no ice, it can feed and grow. Pure golden trout feeds slowly, while hybrid golden trout feeds rapidly. They like to eat aquatic insects, terrestrial insects and small fish. The pool culture condition snatch food artificial bait. The dissolved oxygen of the fish pond water should be more than 3mg/liter to ensure the normal growth of fish in the pond. It takes 24 months at an average annual water temperature of 8℃ and 16 months at 12℃ for the fish to develop from eggs to 500g size adult fish. In general, 1 whole age fish 60 ~ 90 grams, full length of 20 centimeters; 2 whole age fish 450 ~ 500 grams, full length of 35 centimeters; 3 whole age fish 1,000 grams, full length of 45 centimeters, the maximum can reach more than 1,900 grams.
Two, breeding habits and reproductive technology
The average annual water temperature of 8 ℃ golden trout three years sexually mature, 12 ℃ two years sexually mature. The breeding season is from November to January of the following year. after August, as the natural light time becomes shorter and the water temperature decreases, the gonads enter a period of rapid development. The water temperature drops to below 13℃ in November, the oocyte develops to the middle of the second maturation division, the egg is discharged by the follicular tissue, because the ovary is semi-naked, the discharged egg is scattered in the body cavity, the oocyte develops into a mature egg, and the fish enters into the state of oviposition. Above 13℃ water temperature gonads are underdeveloped and cannot reproduce normally. Into the ovulation period after every 7 ~ 10 days on the parent fish for a maturity check, light pressure on the abdomen that is the flow of egg particles can be artificial egg collection. Eggs will be collected into the plastic or stainless steel net basin, and then isotonic liquid shower to pick out the eggs, wash away the festering eggs, feces and other dirt that affect fertilization. After washing the eggs, pour the eggs into the basin, squeeze the semen into the eggs, mix well with your hands and add water, and leave it for 2 to 3 minutes, this fertilization method is called isotonic egg washing artificial insemination. This method of fertilization is called dry conduction artificial insemination. In the absence of ulcerated eggs, direct insemination can also be achieved without washing the eggs, which is called dry conduction artificial insemination. After standing with water to wash away excess semen, it is left in water for 30 to 60 minutes. At this time, the fertilized egg is not resistant to vibration, vibration will lead to yolk membrane breakage, water invasion into the yolk to make it become white and cloudy, resulting in the death of fertilized eggs. During the resting process, the fertilized egg absorbs water and expands, about 17% of the water is absorbed into the egg, and the fertilized egg becomes elastic from soft. After the eggs have absorbed water and swollen, they are transferred to the incubation bucket to be hatched under running water. After the eyes are developed, the eggs are moved into the incubation tank for hatching out of the membrane. The newly hatched juvenile fish is about 2.0 centimeters in length, with a large yolk sac on its abdomen, and will not swim when lying on its side under the water. However, their dorsal and caudal fins already have taxonomically countable traits, so the newly hatched fish are called hatchery fish rather than juveniles. When the hatchling develops to the point where it can swim, it is called a floating juvenile.
After fertilization, it takes 310℃-day to hatch, and the cumulative temperature required after fertilization is about 160℃-day. Fertilized eggs before the development of eyes do not tolerate vibration, and the slightest vibration will lead to death. The eggs after the eye are called hair eye eggs, hair eye eggs are resistant to vibration, hair eye and then after 40 ℃ - days can be removed from the dead eggs and long-distance egg transport operations.
The number of eggs per mature female is 1200 for age 2 fish weighing 500 grams and 2500 for age 3 fish weighing 1300 grams. Fertilized eggs to hair eye eggs during incubation water temperature should be maintained below 13 ℃, hair eye water temperature up to 18 ℃. The dissolved oxygen level of the hatchery discharge water should be kept above 3.5 mg/liter. Preparation of isotonic solution for washing eggs: 90.4 grams of salt NaCl, 2.4 grams of potassium chloride KCl, 5.1 grams of calcium chloride CaCl2-6H2O or CaCl2-2H2O 3.4 grams dissolved in 10 liters of incubation water and stirred until all dissolved can be used to wash eggs.