沅水银鮈年龄与生长的研究

Age and growth of Squalidus argentatus in Yuanjiang River

基于2016年3月至2017年3月采自沅水支流無水的137尾样本,使用耳石和鳞片为年龄鉴定材料,对银鮈(Squalidus argentatus)的年龄结构和生长特征进行了研究。结果显示:研究样本体长范围为40~115 mm,优势体长组为60~100 mm(占86.1%);体重范围为1.1~23.6 g,优势体重组为3~12 g(占77.4%);共4个年龄组,1龄和2龄为优势年龄组(占93.2%)。体长和耳石半径为直线正相关,L=-9.062+258.896×R(n=132,r2=0.773);体长-体重关系方程为:W=8.557×10^(-6)×L3.134(r2=0.974,n=137),银鮈为异速生长鱼类;以退算体长拟合的von Bertalanffy方程为:Lt=177.7(1-e-0.235(t+0.193))(r2=0.909),Wt=96.1(1-e-0.235(t+0.193))3.13。估算的拐点年龄为4.7龄,对应的体长体重分别为120.9 mm和28.7 g。研究表明耳石是银鮈较好的年龄鉴定材料。沅江银鮈的年龄结构趋于简单,面临较大的捕捞压力,渔业主管部门应为保护其种质资源制定相应的措施。

% Squalidus argentatus is a kind o f small - sized fisli which widely distrilD uted in Chinese waters. In order to e x -plore the age structure and growtli characteristics of S. ar〈;entatus’ a tota l of 137 samples were collecteRiver from March 2016 to March 2017. The ages were determined usin g scales and otoliths respectively. T h e stock o fS. argentatus has a relatively simple age structure which contains 4 age classes ranging from 1 to 4. The dominan t age classes were 1-2 years old accounting for 93. 2% o f the total samples and standard length range was 4 0 - 115 m m,mainly b e -tween 60 mm and 100 mm（86. 1% ）. The weight range was 1. 1 ？ 23. 6 g,mainly between （ g and 12 g （77. 4% ）. There was a positive linear correlation between standard length （B） and otolithsradiu s （ E ） ,wh ich c9. 062 4258. 896 xE （ n = 1 3 2, r2 =0. 7 7 3）. The relations hip bet^ ween standard L and W was po wer exponent and cou ld be expressed as W = 8. 557 x 10 6 x L3.134 （ r2 = 0. 9 7 4,n = 1 （7 ）,which meant growth type was allometry. Von Bertalanffy growth functions were Lt = 177. 7 （1 - e _〇 .2（5（I ＋ a19（）） and Wt = 96. 1（ 1 - e _a2（5（I＋（019（））（.1（ . The growth4. 7 years and the corresponding standard length and weight were 120. 9 mm and 28. 7 g respectively. The results s ho wedthat sectioned lapillus was a better ageing material o f the fish. No w the age structure o f S. stock was simple,some measures should be taken to p rotect this fish and reduce the fishing efforts.