乌江思南泉水鱼的年龄与生长研究

Age and Growth of Pseudogyrinocheilus procheilus in Sinan Section of Wujiang River

2011-2012年在乌江思南江段采集454尾（雌性298尾,雄性109尾,性别不辨47尾）泉水鱼（Pseudogyrincheilus procheilus）,以鳞片作为材料对年龄进行鉴定,利用软件FISAT-II处理体长与年龄数据,对其生长方程、生长拐点等生物学特征进行了研究。结果表明,泉水鱼鳞片为圆鳞,年轮主要表现为普通切割型与普通疏密型;年龄组成为1～4龄,其中以2～3龄为主;1～4龄,体长增长率为47.4%,雌性体长增长率达50.4%,雄性体长增长率为35.0%,体重增长率为438.5%,雌性体重增长率为485.1%,雄性体重增长率为275.9%;体重（W）与体长（L）呈幂指数关系：W=2×10^（-6）L3.4784（R2=0.8824）,雌鱼为：W=3×10^（-6）L3.4002（R2=0.8505）,雄鱼为：W=2×10^（-5）L3.019（R2=0.8112）;体长（L）和鳞径（S）呈幂函数相关：L=92.597S0.5458;Von Bertalanfy生长方程的各参数为：渐进体长L∞=278.10 mm,生长系数k=0.22,t0=-1.80;雌鱼各参数为：L∞=355.01 mm,k=0.14,t0=-2.38;雄鱼各参数为：L∞=224.04 mm,k=0.32,t0=-1.72,雄鱼达到渐进体长的速度比雌鱼要快得多;体长生长速度和加速度不具拐点,生长速度随年龄增加而递减,生长加速度始终为负值,随年龄增加而增大;体重生长速度和加速度都具有拐点,拐点年龄ti=3.87,拐点体长Li=198.22 mm,拐点体重Wi=195.59 g。结合泉水鱼生长拐点年龄和性成熟年龄,为保护乌江思南泉水鱼资源,建议以180 mm为最小捕捞个体的体长。

Pseudogyrinocheilus procheilus is a Cyprinidae native to China,inhabiting the Yangtze River above Yichang,tributaries of the Yangtze River in Sichuan and the Wujiang River. In this study,the age structure and growth characteristics of P. procheilus were analyzed,based on a field investigation in the Sinan section of Wujiang River. The objective was to provide basic biological data and a theoretical basis for resource conservation and artificial propagation. A total of 454 P. procheilus specimens（ 298 females,109 males,gender of 47 samples undefined） were collected in 2011 and 2012. Total length,body length and body weight were measured and scales were sampled for age determination. Growth features were analyzed using FISAT-II software including growth functions,growth index and inflexion point. The scale annuli were mainly of the cutting type and sparse-dense type. The P.procheilus sample population was composed of 1 to 4 year-old and dominated by 2 to 3 years old. The growth rate of body length was 47. 4% for all samples,50. 4% for females,and 35. 0% for males. The growth rate of body weight was 438. 5% for all samples,485. 1% for females,and 275. 9% for males. The body length-weight relationships were expressed as： W = 2 × 10^（-6）L3. 4784（ R2= 0. 8824） for all samples,W = 3 × 10^（-6）L3. 4002（ R2= 0. 8505）for females and W = 2 × 10^（- 5）L3. 019（ R2= 0. 8112） for males. The relationship between body length and scale radius was described by a power function： L = 92. 597S0. 5458. The growth parameter values,derived using Von Bertalanffy growth equation,were： L∞= 278. 10 mm,k = 0. 22,t0=- 1. 80 for all samples; L∞= 355. 01 mm,k = 0. 14,t0=- 2. 38 for females; L∞= 244. 04 mm,k = 0. 32,t0=- 1. 72 for males. Males reached asymptotic length sooner than females. P. procheilus displayed an inflexion point in growth rate and growth acceleration of body weight,with parameters,ti= 3. 87,Li= 198. 22 mm,Wi= 195. 59 g. Scales are a reliable age determination material for P. procheilus for ages 2- 3 years. To protect P. procheilus in Wujiang River,the minimum catchable size should not be less than 180 mm in body length considering both the age of growth inflexion and the age of sexual maturity.