Age,Body Growth and Reproductive Characteristics of Triplophysa yarkandensis

We studied the age structure,body growth and fecundity of Triplophysa yarkandensis based on 264 samples collected from Kezi River in southern Xinjiang Uygur Autonomous Region in May 2008.The age of samples ranged from 2 to 11 years old,most individuals(94.49%) were aged 2 to 4 years old.Average body length and body weight of female were 9.39 ± 2.10 cm and 16.55 ± 15.85 g,and male were 9.17 ± 2.27 cm in length and 15.38 ± 15.20 g in weight,no significant differences between female and males(P 0.05).Relationships of body length and body weight were W♀ +♂ = 0.014 0L2.988 9(r = 0.975 4),W♀ = 0.016 7L2.889 5(r = 0.980 9),W♂ = 0.011 7L3.083 1(r = 0.975 7).Growth index and annual weight increment appeared peak at four years old,1.86 and 18.79 g per year,respectively.Sex ratio was 0.7∶ 1.0(♀∶♂),and individual matured in two years old.The minimum mature body length and weight of female were 6.2 cm and 4.46 g,meanwhile the male were 4.6 cm and 1.67 g.Absolute fecundity ranged from 6 136 to 405 555 and the mean value was 28 716 ± 42 698,the relative fecundity were from 672 to 6 134(eggs per gram) and the mean value was 2 310 ± 1 427.The distribution of egg diameters showed a single peak,which might indicate one-time spawning of this population.The breeding season was from late May to late June based on the daily growth of 19 juvenile fish captured in August 2008.