羊卓雍错高原裸鲤(Gymnocypris waddellii Regan)繁殖生物学研究

Reproductive biology of Gymnocypris waddellii Regan in Yanmdrok region

2006年3-7月在的卡鲁雄曲、绒波藏布等主要支流收集了225尾高原裸鲤开展繁殖生物学研究.结果表明,高原裸鲤有溯河产卵习性,繁殖期为5-8月份,水温变化在9.5-18.5℃,流速以0.3-0.8m/s为多,水深15-50 cm为主.初次性成熟雌雄均为5龄,繁殖季节第二性征雌雄差别明显.雄性最小性成熟个体体长19.5 cm,体重80g,成熟系数4.6%;雌性最小性成熟个体体长21 cm,体重95g,成熟系数6.3%;成熟卵呈桔黄色,圆球形.卵粒平均卵径2.22mm,变动幅度在1.92-3.32mm,卵粒质量为63-214粒/g,平均115粒/g.繁殖群体绝对怀卵量1086-11400粒,平均4446粒;相对怀卵量6.2-36.1粒/g,平均18.0粒/g;成熟系数5.7%-25.8%,平均16.2%.繁殖群体主要由8、9、10龄个体组成,雌雄性比为1∶1.16,繁殖力与体长和体重都呈正相关.

In order to study the reproductive biology of Gymnocypris waddellii Regan,we collected 225 fishes in Karuxung River and Rongbuk Zangbo River which are located in Yanmdrok region from March to July in 2006.The results show that G.waddellii Regan has anadromous habit and reproduces from May to August with water temperature of 9.5-18.5℃,flow rate of 0.3-0.8m/s and depth of 15-50cm.All female and male firstly start to reproduce at 5 ages and their secondary sexual features are significantly different between male and female.The smallest sex mature male with 80 g weight has mature coefficient of 4.6% with body length of 19.5cm.The smallest sex mature female with 95 g weight has mature coefficient of 6.3% with body length of 21cm.The mature eggs are orange and round balls with diameter ranging from 1.92 to 3.32mm,and the mean diameter of mature eggs is 2.22mm.The number of eggs within one gram varies from 63 to 214 eggs with mean of 115 eggs.The absolute fecundity of brood stocks varies from 1086 to 11400 eggs and the mean is 4446 eggs.The relative fecundity varies from 6.2 to 36.1 eggs/g with mean of 18.0 eggs/g.The mature coefficient varies from 5.7% to 25.8% with mean of 16.2%.The brood stocks are composed mainly of individuals aged 8,9 and 10 with sex ratio of females to males of 1∶1.16.Fecundity was positively correlated with body length and weight,respectively.