Morphometric Differentiation of Two Nigerian Fish Species (Oreochromis niloticus and Lates niloticus) Using Principal Components and Discriminant Analysis Diferenciaci車n Morfom谷trica de Dos Especies de Peces Nigerianos (Oreochromis niloticus y Lates niloticus) Utilizando An芍lisis de Componentes Principales y An芍lsis Discriminante

作者：A Yakubu; S A Okunsebor

来源：International Journal of Morphology, 2011.

• Pescado
• Genotipos
• Conservacion
• Caracteristicas morfologicas
• Analisis multivariado
• Nigeria
• Fish
• Genotypes
• Conservation
• Morphological traits
• Multivariate analysis
• Nigeria

Morphological differences between two close fish populations were investigated in Doma Dam, north central Nigeria using principal component and discriminant analyses. The purpose was to identify the two species correctly and assign them into distinct genetic groups. To achieve this, seven morphometric measurements (body weight, standard length, total length, head length, body depth, dorsal fin length and caudal fin length) were made on each of the studied 252 fish specimens (153 Oreochromis niloticus and 99 Lates niloticus). The analysis of variance showed that significantly (P%26lt;0.05) higher values were recorded for Lates niloticus in all the body traits examined, except dorsal fin length. From the principal component analysis, the differences between the species resulted mainly from dorsal fin length, body weight, caudal fin length and head length. The stepwise discriminant analysis revealed that standard length, dorsal fin length and caudal fin length were the three most discriminating variables useful to distinguish clearly the two species at mature age. These three variables with strong discriminating power correctly classified 98.0% of individuals from the sample of known-fish populations. The classification accuracy was cross-validated using split-sample method, and indicated a 97.6% success rate (98.0% of Oreochromis niloticus and 97.0% of Lates niloticus were correctly assigned). The results can provide a sound scientific basis for the effective management and sustainable exploitation of the genetic resources of the two species under subtropical conditions. Las diferencias morfol車gicas entre dos poblaciones de peces similares se han investigado en Doma Dam, centro-norte de Nigeria utilizando an芍lisis de componentes principales y an芍lisis discriminante. El prop車sito fue identificar correctamente las dos especies y asignarlas a los distintos grupos gen谷ticos. Para lograr esto, siete medidas morfom谷tricas (peso corporal, longitud est芍ndar, longitud total, longitud de la cabeza, profundidad del cuerpo, longitud de la aleta dorsal y la longitud de la aleta caudal) se realizaron en cada una de las muestras de los 252 peces estudiados (153 Oreochromis niloticus y 99 Lates niloticus) . El an芍lisis de varianza mostr車 que de forma significativa (p%26lt;0,05) los valores m芍s altos se registraron en Lates niloticus, en todos los rasgos del cuerpo examinado con excepci車n de la longitud de la aleta dorsal. A partir del an芍lisis de componentes principales, las diferencias entre las especies se observ車 principalmente en la longitud de la aleta dorsal, el peso corpora