新疆额尔齐斯河银鲫年龄鉴定比较与生长特征研究

Comparitive Study of Age Determination and Growth Characteristics for Carassius auratus gibelio in the Irtysh River,Xinjiang

为了探究不同材料对鱼类年龄鉴定的准确性,以2013年4-10月从新疆额尔齐斯河采集的546尾银鲫（Carassius auratus gibelio）样本为材料,比较4种钙化组织（微耳石、鳞片、鳃盖骨和脊椎骨）年龄鉴定结果,选择最佳的年龄鉴定材料,研究其生长特征。结果表明,4种钙化组织中,微耳石磨片年龄读数的平均百分比误差（IAPE）最低（1.89%）,同一观察者2次读龄的吻合率最高（91.9%）,为4种材料中最为准确的年龄鉴定材料。采用微耳石进行年龄鉴定,银鲫样本由1~9龄组成,以3~4龄为主,占77.28%;银鲫体长与体重呈幂函数关系,雌雄群体间无显著性差异,体长（L,mm）与体重（W,g）的关系为：W=2.661×10-5L3.085（R2=0.96,n=546）;生长规律用von Bertalanffy生长方程表示为Lt=359.7[1-e-0.172（t＋1.066）],Wt=2 042.3[1-e-0.172（t＋1.066）]3.085;银鲫个体的生长拐点年龄为5.49龄,对应的体长及体重分别为243.2 mm和610.81 g。

Carassius auratus gibelio（ Bloch,1782） is a commercially important fishery resource in the main stem and affiliated waters of Irtysh River. Human activities and over fishing have led to an abrupt decline in C. gibelio populations in Irtysh River. This study compared four ageing materials from C. gibelio and characterized the age structure and growth characteristics of the Irtysh River population. The data collected is essential for understanding population dynamics,changes in resource quantity and provides a scientific basis for conserving C. gibelio and determining the annual catch that can be sustained in Irtysh River. A total of 546 C. gibelio specimens were collected from the Irtysh River from April to October,2013,and the body length and mass of each specimen was measured.Four calcified structures（ scale,operculum,vertebra and otolith） were used for age determination; Percent agreement and average percent error of C. gibelio ageing for duplicate readings by a single observer were compared to determine which structure produced the most precise and accurate age estimation. Results indicate that the otolith is the best material for C. gibelio ageing with the lowest average percent error（ 1. 89%） and highest agreement（ 91. 9%）. The body mass and body length of the fish catch ranged from 1. 12 g to 1 171. 63 g and from 33 mm to328 mm,with average values of（ 404. 21 ± 178. 11） g and（ 206. 8 ± 36. 55） mm. C. gibelio in the range of 250-600 g and 170- 240 mm dominated the fish catch,accounting for 79. 85% and 78. 94% of the total specimens.The fish collected ranged in age from one to nine years,dominated by individuals of 3 to 4 years（ 77. 28 %）,but fish aged 5 years and older decreased sharply（ 12. 86%）. Data was fitted to a power function to describe the weight-length relationship,W = 2. 661 × 10- 5L3. 085（ R2= 0. 96,n = 546）,and the relationship was not significantly different between male and female. The growth pattern of C. gibelio was described by the von Bertalanffy equation as Lt= 359. 7[1- e- 0. 172（ t ＋ 1. 066）],Wt= 2 042. 3[1- e- 0. 172（ t ＋ 1. 066）]3. 085. The inflection point for C. gibelio growth was 5. 49 with a body length of 243. 2 mm and body weight of 610. 81 g.