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Vol. 51 No. 2, 2012
Age and Growth of Oxygymnocypris
stewartii (Cyprinidae:
Schizothoracinae) in the Yarlung Tsangpo River, Tibet, China
Bin
Huo, Cong-Xin Xie*, Bao-Shan Ma, Xue-Feng Yang, and Hai-Ping Huang
College
of Fisheries, Huazhong Agricultural Univ., Wuhan, Hubei 430070, China
Bin Huo, Cong-Xin Xie, Bao-Shan Ma, Xue-Feng Yang, and
Hai-Ping Huang (2012) To better understand the biology of Oxygymnocypris stewartii and its relationship with
management considerations, the age and growth of O. stewartii were examined using
sectioned otoliths of 712 specimens collected from Aug. 2008 to Aug.
2009. The standard length (SL) ranged 45-587 mm. The location of the
1st annulus was validated by a daily growth increment (DGI) analysis of
otoliths. Monthly changes in the marginal increment ratio of the
otoliths with 1-8 annuli indicated that an annulus forms once a year,
from Mar. to June. The index of the average percentage error (IAPE) of
the sectioned otoliths was 0.5%, and the coefficient of variation (CV)
for the age estimation was 0.7%. Estimated ages ranged 3-17 yr for
males, 2-25 yr for females, and 1-6 yr for those of undetermined sex.
The SL-BW relationship was described as BW = 6.108 × 10-6 SL3.126
for females, BW = 9.872 × 10-6 SL3.052 for males,
and BW = 3.203 × 10-5 SL2.821 for undetermined. The von Bertalanffy
function was used to model the observed length-at-age data as Lt = 526.8 {1 -
exp[-0.141 (t - 0.491)]} for
males, and Lt =
618.2 {1 - exp[-0.106(t -
0.315)]} for females. Females grew at a slower rate but attained a
larger size than males. Knowledge of this species’
Key words: Age, Growth, Otolith, Oxygymnocypris stewartii, Tibet.
*Correspondence: Tel: 86-27-87286862. Fax: 86-27-87282114.
E-mail:xiecongxin@mail.hzau.edu.cn
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