Morphological identification and taxonomic relationship of farmed fish of the genus chrysichthys

Variation of Chrysichthys nigrodigitatus, C. maurus and C. auratus from the fish farm of Jacqueville were studied using morphometric and meristic analyses. The morphological analysis included thirty nine morphometric measurements and eight meristic counts. The Principal Component Analysis and the Discriminant function Analysis were used in order to determine morphological difference and relationship between the species of Chrysichthys. Average of coefficient of variation of morphometric was lower (CV< 30 %) for all variables within groups, except NBL and MBlL2, showing that most of the morphometric characters were not variable among three species of Chrysichthys. The specimens of C. nigrodigitatus were significantly differentiated from those of C. maurus and C. auratus. These last two species were morphologically similar. C. nigrodigitatus were distinguished from the other species by a large occipital process, a long nasal barbell. In this species, the mandible barbells and the nostrils were well separated. In addition, this species is defined by the higher number of branched anal fin rays, the number of gill raker on the epibranchial of the first gill arch and the number of gill raker on the cerato and hypo-branchial of the first gill arch. The utility of morphometric measurements for discriminating Chrysichthys species has been demonstrated but the result must be corroborated by genetic analysis.