三个地理种群鲂的形态差异与判别分析

采集了北江、钱塘江、金沙河水库3个地理种群的鲂（Megalobrama skolkovii）414尾样本，用传统形态学和框架分析法，运用单因素方差分析、聚类分析、主成分分析和判别分析法比较研究了37个形态比例性状。结果表明：3个种群的口裂长／头长、吻长／头长、口宽／头长、上颌厚／头长、全长／体长、体厚／体长、头长／体长、尾柄长／体长、尾柄高／体长、尾柄长／尾柄高、1—2／体长、1—3／体长、2—4／体长、2—5／体长、3—5／体长、4—5／体长、4—6／体长、4—7／体长、5—6／体长、6—8／体长、6—9／体长、7—8／体长，及7—9／体长23个性状差异显著（P〈0．05）（1：吻端；2：头部后缘；3：胸鳍起点；4：背鳍起点；5：腹鳍起点；6：背鳍基部末端；7：臀鳍起点；8：尾鳍背部起点；9：尾鳍腹部起点）；聚类结果显示，北江与金沙河水库首先聚为一类，认为北江群体与金沙河水库群体形态最为相似；主成分分析构建了9个主成分，累计贡献率为60．26％；以Bayes逐步判别分析方法选用18个判别效果较好的比例性状建立了3个鲂地理种群的判别函数，判别率为99．03％。结果显示，可以通过形态比例性状来判断鲂的3个地理群体的归属。

Morphological Variation and Discriminant Analysis of Three Geographical Populations of Freshwater Bream Megalobrama skolkovii

In the present paper, 37 morphological proportional characters were measured by traditional morphological and truss network analysis and analyzed in 414 samples of freshwater bream Megalobrama skolkovii collected from Beijiang River, Qiantang River, and Jinsha River Reservoir by one-way analysis of variance, cluster analysis, principle component analysis, and discriminant analysis to investigate the morphological variation and population biology. The result of one-way analysis of variance revealed that 23 morphological proportional characters （MGL/HL, PD/HL, MW/HL, UJW/HL, TL/SL, BW/SL, HL/SL, CPL/SL, CPH/SL, CPL/CPH, 1-2/SL, 1-3/SL, 2-4/SL, 2-5/SL, 3-5/SL, 4-5/SL, 4-6/SL, 4-7/SL, 5-6/SL, 6-8/SL, 6-9/SL, 7-8/SL, 7-9/SL） l：Tip of maxillary;2： forehead （end of frontal bone） ; 3 ： origin of pectoral fm; 4 ： origin of dorsal fin; 5 ： origin of pelvic fin; 6 ： termination of dorsal fin; 7 ： origin of anal fin; 8：dorsal side of caudal peduncle, at the nadir;9：ventral side of caudal peduncle, at the nadir） were significant different （P〈0.05） among the three populations of freshwater bream. The cluster analysis indicated that the freshwater bream in Beijiang River were most similar to that in Jinsha River Reservoir with morphological characters. In the principal component analysis, nine principal components were constructed by factor loading, with the cumulative contribution ratio of 60.26%. These populations were separated by discriminating analysis. The discriminating functions were established in the three populations based on 18 significant different morphological proportional charasters,with total diserimination accurac,y of 99.03%. The findings indicate that the orgin of three populations can be determined by differences in morphological proportional characters.