青海湖裸鲤生长特征的研究

STUDIES ON GROWTH CHARACTERISTICS OF GYMNOCYPRIS PRZE WALSKII PRZEWALSKII

对2002年5月—2003年7月采自青海湖的1174尾青海湖裸鲤样本年龄进行了耳石鉴定,并依据年龄推算了生长率。青海湖裸鲤体长与体重的关系为:W=0.000174×L2.4990(♀)、W=0.0000402×L2.7538(♂),雌、雄个体生长差异显著。其体长Von Bertalanffy生长方程为:Lt=551.9301(1-e-0.0711(t+0.3044))(♀),Lt=682.8688(1-e-0.0530(t+0.4240))(♂);体重Von Bertalanffy生长方程为:Wt=1237.3431(1-e-0.0711(t+0.3044))2.4990(♀),Wt=2567.3242×(1-e-0.0530(t+0.4240))2.7538(♂)。其雌、雄生长拐点分别为12.57龄和18.67龄。

In this study, 1175 samples of Gymnocypris przewalskii przewalskii, which were collected from the Qinghai lake from May, 2002 to July, 2003, were aged by determining the annuli of otoliths. Regressive body length was used to fix the Von Bertalanffy function. Otoliths are good materials in age determination, which have relatively clear annuli and are unlikely to lose annuli because of absorption or erosion. Besides, the growth rates were calculated from the ages of these fish samples. The survey during the period from May to August showed that the sex ratio of males to females in the brood stock was 1.66 to 1 .This is consistent with the results of the statistics in the 60s and 90s of the 20^th century. In all the brood stocks, the body length and body weight of the smallest male individual at the age of 4 was 130.0mm and 28.0g, respectively,while the body length and body weight of the smallest female individual at the age of 5was 170.0mm and 51.0g, respectively. The age composition was from 4 to 11. The mean body length and body weight of female were bigger than those of male. The body length and body weight was in the relation of power function. The relationship of body length to body weight for the female was W = 0.000174 × L^2.49899, and that for the male W = 0. 0000402×L^2.75382. There was a significant difference in growth between the female and male. Their growth could be described by Von Bertalanffy equations Lt = 551.9301 [ 1 - e^-0.07112（t＋0.3044） ] （female）, Lt = 682.8688[ 1 - e^-0.05304（t＋0.4240） ]（male）, Wt = 1237.3431（1 - e^-0.0711（t＋0.3044）2.4990（female）, Wt = 2567.3242 （1 - e^-0.0530（＋0.4240））^2.7538（male）. The inflection points for the growth of female and male were 12.57 and 18.67, respectively. Otolith described the growth of Gymnocypr/s przewalskii prz.ewalskii well, scale and dorsal fin spine could not do better.