根据2009年8月-12月在长江常熟江段采集的362尾似鳊Pseudobrama simoni样本,对其年龄、生长特征和形态特征进行了研究。结果表明:似鳊种群由1-3龄共3个年龄组组成,1龄鱼为优势群体,占总数的51.3%;体长分布范围为62.33-133.65 mm,优势体长范围为75-110 mm (占总数的75.41%),体质量分布范围为3.70-46.10 g,优势体质量范围为3.70-18.70 g (占总数的80.11%);雌、雄个体的体长、体质量差异极显著(P〈0.01),丰满度、体高、头长等31个形态指标无显著性差异(P〉0.05);体长与鳞径的关系式为L♀=391.67R4-2211.8R3+4609.7R2-4171.4R+1463.2(n=156,P〈0.001,r2=0.6973), L♂=171.22R4-895.44R3+1719.8R2-1406.4R+486.47(n=178,P〈0.001,r2=0.7821);体长和体质量的关系式为W♀=4.52×10-6L3.2901(n=156,r2=0.94), W♂=1.09×10-5L3.0915(n=178,r2=0.98); Von Bertalanffy生长方程为Lt♀=142.31×[1-e-0.1125(t+8.3442)], Lt♂=153.73×[1-e-0.1024(t+6.8309)]。研究表明,雌性似鳊体质量生长拐点年龄为2.24龄,雄性为3.96龄,常熟江段似鳊呈低龄化态势。
The age, growth and morphological features were investigated in 362 samples of Pseudobrama simoni col-lected in Changshu section of Yangtze River from August to December of 2009 in order to reveal the population and growth status. It was found that the population of Pseudobrama simoni was comprised of 3 age classes ranging from dominantl 1 year old individuals (accounting for 51. 3%) to 3 year old individuals. The population of Pseudobrama simoni was changed from 62. 33 mm to 133. 65 mm in body length, primarily between 75 mm to 110 mm, represen-ting 75. 41% of the samples. The Pseudobrama simoni had body weight from 3. 70 g to 46. 10 g, mostly between 3 . 70 g to 18 . 70 g accounting for 80 . 11%, with significant differences in body length and body weight and without significant differences in condition factor, body depth, head length and other 28 morphological features between fe-male and male. The regression equation between scale radius ( R) and body length ( L) was expressed as L♀=391. 67R4-2211. 8R3+4609. 7R2-4171. 4R+1463. 2(n=156,P〈0. 001,r2=0. 6973),and L♂=171. 22R4-895. 44R3+1719. 8R2-1406. 4R+486. 47(n=178,P〈0. 001,r2=0. 7821),while the regression equation between body length and body weight(W) was described as W♀=4. 52×10-6L3.2901(n=156,r2=0. 94),W♂=1. 09×10-5 L3.0915(n=178,r2=0. 98). The growth characteristics of the fish were described by the Von Bertalanffy growth equa-tion Lt♀=142. 31 ×[1-e-0.1125(t+8.3442) ],and Lt♂=153. 73 ×[1-e-0.1024(t+6.8309) ]. The growth inflexion point was found to be t=2. 24 year old in the female, and t=3. 96 year old in the male, young tendency in the lower reaches of Yangtze River.