雅鲁藏布江下游弧唇裂腹鱼的年龄结构与生长特性

研究以采自雅鲁藏布江下游墨脱段的928尾弧唇裂腹鱼(Schizothorax curvilabiatus)为研究对象, 对耳石、脊椎骨和鳃盖骨三种年龄材料的准确性进行比较, 并对其种群年龄结构和生长特性进行研究。结果表明, 耳石是鉴定弧唇裂腹鱼最适合的年龄材料。弧唇裂腹鱼体长为48—508 mm, 体重为1.8—1898.9 g。体长体重关系式为W =2.279×10–5 SL 2.931。雌鱼最大年龄43龄, 雄鱼最大年龄23龄。von Bertalanffy生长方程为雌性: L_t= 590.21–e–0.096(t–0.282)], W_t=3016.81–e–0.096(t–0.282)]2.931; 雄性: L_t=575.31–e–0.090(t+0.011)], W_t=2798.91–e–0.090(t+0.011)]2.931。弧唇裂腹鱼雌性和雄性的拐点年龄分别为11.5龄和11.9龄。研究结果表明弧唇裂腹鱼生长缓慢、寿命较长, 为典型的K-对策选择者。随着雅鲁藏布江下游河流环境受到的人为干扰逐渐加大, 应从控制捕捞、栖息地保护和加强人工繁育等方面保护弧唇裂腹鱼的种群资源。

CHARACTERISTICS OF AGE AND GROWTH OF SCHIZOTHORAX CURVILABIATUS IN THE LOWER REACHES OF THE YARLUNG ZANGBO RIVER

Estimating age structure of fish populations and growth of individuals are fundamental to assessing fish population dynamics and formulation of effective fisheries management. Obtaining accurate age information is the first step for precise understanding of these metrics. As one of the dominant species in the lower reaches of the Yarlung Zangbo River, little is known about the age estimations of Schizothorax curvilabiatus. 928 specimens of S. curvilabiatus were collected from December 2015 to November 2016 in the Motuo reach. Otoliths, vertebrae and opercular bones were examined to assess the suitability of the three calcified structures for age estimation. The results showed that otoliths were more suitable than vertebrae and opercular bones for age estimation of S. curvilabiatus. The standard length (SL) of S. curvilabiatus ranged from 48 to 508 mm, weight (W) ranged from 1.8 to 1898.9 g. The range of estimated age was 2—23?years for males, 2—43?years for females, and 1—4?years for those of undetermined sex. S. curvilabiatus populations in the Motuo reach were dominated by the specimens of 3—5 years. The intercept of length-weight relationship showed no difference between sexes and the function was described as W=2.279×10–5 SL2.931. The von Bertalanffy function was used to model the observed length-at-age data as L_t=590.2 1–e–0.096(t–0.282)], W_t=3016.8 1–e–0.096(t–0.282)]2.931 for females, and L_t=575.3 1–e–0.090(t+0.011)], W_t=2798.9 1–e–0.090(t+0.011)]2.931 for males. The inflexion point for the growth of females and males were 11.5 and 11.9 years, respectively. Accordingly, reasonable conservation measures, such as controlling fishing, habitat protection and strengthening artificial breeding, are needed to maintain the fish stock for future generations due to the increasing anthropogenic activities in the lower Yarlung Zangbo River.