闽江中游鲢的年龄与生长

为了研究闽江中游鲢的年龄组成和生长情况,根据2015年6月—2017年3月在闽江中游段采集的126尾鲢(Hypophthalmichthys molitrix)样本,通过对其鳞片年轮的观察和基础生物学测定,研究鲢的年龄判定与生长特性。结果显示:闽江中游鲢的体重范围为310.6~9420.8 g,体长范围为23.4~86.9 cm;鳞片的年轮主要表现为闭合切割型和疏密特征,由1 ⁺~7 ⁺共7个年龄段组成,其中优势年龄组为3 ⁺~4 ⁺龄。体长与体重呈显著的幂函数关系:W=0.027×L ^2.953,幂指数接近3,表明闽江中游鲢属于匀速生长类型。拟合Von Bertalanfly的生长方程为:L_t=106.696×1-e ^{-0.147( t +1.1443)}],W_t=26332.083×1-e ^{-0.147( t +1.1443)}] ^2.953。生长拐点年龄为t_i=5.923,与其他水域鲢种群相比,其生长性能略低。因此,建议闽江中游鲢的开捕规格体长大于70 cm,体重大于7.7 kg,同时规范渔具渔法,以降低捕捞强度,加大资源养护力度,促进闽江鲢资源的恢复和保护。

Age and Growth of Hypophthalmichthys molitrix in the Middle of the Minjiang River

To reveal the age and growth of silver carp (Hypophthalmichthys molitrix) in the middle of the Minjiang River, 126 specimens were collected from June 2015 to March 2017 in the middle of the Minjiang River, the scale rings’ observation and basic biology measurement were conducted to determine the age and growth characteristics. The results showed that the body weight of the silver carp ranged from 310.6 to 9420.8 g, and the body length ranged from 23.4 to 86.9 cm. The scale rings were closed cutting type and had sparse and dense characteristics. The age of the individuals ranged from 1 ⁺ to 7 ⁺, and most of the individuals aged 3 ⁺ to 4 ⁺. The obvious power function relationship between body length (L) and body weight (W) could be expressed as W=0.027×L ^2.953, power exponent approached 3. The silver carp in the middle of the Minjiang River was of the uniform growth type, and its growth could be described by the Von Bertalanfly growth equations: L_t=106.696×1-e ^{-0.147( t +1.1443)}], W_t=26332.083×1-e ^{-0.147( t +1.1443)}] ^2.953. The growth inflection t_i=5.923. Compared with silver carps in other water, its growth performance was slightly lower. Therefore, the fist capture of silver carp in the middle of the Minjiang River should be greater than 70 cm length and 7.7 kg weight. At the same time, we should regulate fishing gear and fishing methods to reduce fishing intensity and increase resource conservation efforts, so as to promote the recovery and protection of the silver carp resources in the Mingjiang River.