Vol. 51 No. 7, 2012

Reproductive Biology of Schizothorax o’connori (Cyprinidae: Schizothoracinae) in the Yarlung Zangbo River, Tibet

Bao-Shan Ma^1,2, Cong-Xin Xie^1,*, Bin Huo¹, Xue-Feng Yang¹, and Shui-Song Chen³

¹College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei 430070, China
²Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan, Hubei 430223, China
³Yangtze Valley Water Environmental Monitoring Center, Wuhan, Hubei 430010, China

Bao-Shan Ma, Cong-Xin Xie, Bin Huo, Xue-Feng Yang, and Shui-Song Chen (2012) The reproductive biology of Schizothorax o’connori (Cyprinidae: Schizothoracinae) was studied by examining 1126 individuals collected between Aug. 2008 and Aug. 2009 in the Yarlung Zangbo River, Tibet.  The population had a significantly higher proportion of females than males (X² test, p < 0.05).  Using a logistic regression, it was determined that the standard lengths at 50% maturity were 304 mm for males and 389 mm for females; the ages at 50% maturity were 8 yr for males and 10 yr for females.  Based on the monthly proportions of macroscopic gonadal maturity stages and monthly variations in the gonadosomatic index, S. o’connori spawned over a short period, from Feb. to Apr. with a peak in Mar.  Females had heavier livers than males for a given eviscerated weight (ANCOVA, p < 0.05).  According to the size distribution of oocytes, S. o’connori appeared to show a high degree of spawning synchronicity.  The estimated values of fecundity ranged 8228-39,343 (21,190 ± 6990) eggs/fish.  The relative fecundity ranged 6.2-22.2 (14.3 ± 3.3) eggs/g of fish.  The fecundity of S. o’connori increased linearly with the standard length and total weight, but had no significant correlation with age.

Key words: Reproductive biology, Spawning season, Fecundity, Schizothorax o’connori, Tibet.

*Correspondence: Tel: 86-027-87286862.  Fax: 86-027-87282114.    E-mail:xiecongxin@mail.hzau.edu.cn