| Gymnocypris eckloni Herzensten is a species endemic to China, which is mainly distributed in the Yellow River and its tributaries and lakes in Qinghai Tibet Plateau.At present the research to Gymnocypris eckloni Herzensten is little, its biological characteristics of reproduction and embryonic development haven’t been reported. This article makes a preliminary study on the biological characteristics of Gymnocypris eckloni Herzensten, and studied the reproductive biology and the embryonic development and artificial cultivation. The results are as follows:1. The study on biological characteristicsThe body length and weight of the Gymnocypris eckloni Herzensten is: L =7.4 ~ 50.0 cm, m =7.04 ~ 1960 g. For 7 years and above the individual selection, the age is determined by aural calculus, but under the 7 years is determined by dorsal fin. The function between body length and weight is W=0.008425L3.189, b=3.189, it is close to isometric growth.2. The study on reproductive characteristicsThe female minimum age of sexual maturity is 4 years old; male minimum age of sexual maturity is at the age of 3. The reproductive season is from April to May, and may sometimes be delayed until July to June, in late May for the spawning season.The mean value of the mature egg diameter was(0.21 + 0.01) cm, which was slightly viscous. In distilled water, the average life expectancy of sperm is about 1 ’12 ". In NaCl solution, with the increase of the concentration of NaCl solution, the sperm average life expectancy increases first, decrease and NaCl solution at a concentration of 0.25%, the longest life expectancy, 10 ’24 ".3. The studies on the development of embryos at different temperaturesThe fertilized eggs have hatching in the water temperature of 16℃, lasted 150h45 min from the fertilized egg to hatch out of the membrane. Embryonic development is divided into 6 stages: The fertilization stage, cleavage and blastocyst stage, gastrula stage, neurula stage, organogenesis stage and hatching stageAt different temperatures, the embryonic development at 16 to 31 degrees Celsius, when the temperature at 16 degrees Celsius to 25 degrees Celsius, with the experimental temperature of the incubation time of the embryo is shortened. When the temperature is 16 degrees larvae incubation time for 150 hours and 45 minutes, when the water temperature is 19 degrees, larvae hatched in time only 113 hours 50 minutes. When the temperature reached 28 degrees isn’t normal embryo hatching.4. The artificial cultivationG. eckloni broodstock domestication survival rate was 80.56%, the average rate of growth for 7.3 cm, the growth rate is 15.84%, with an average weight gain of 350 g, increasing weight rate is 36.46%.G. eckloni larvae in sixth days feeding, the initial feeding rate was 42.86%, irreversible starvation point in the 12.5d~13d. The average survival rate of the openings was 73.1%.After hatching, the first 5 days basically rely on the nutrition of the yolk to survive, don’t need to feed. From the 5th day fry basically begin feeding opening, use egg yolk suspension for opening bait, 8 days after the film began feeding water earthworm, 12 days after the film began to cast feed the food conversion feed. |
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