Variation in morphometric and meristic traits of Aspidoparia morar from Brahmaputra and Barak Rivers of Assam, India

The minor carp, Aspidoparia morar is a benthopelagic fish belonging to the sub-family Danioninae under the family Cyprinidae. It has emerged as the single most dominant species in the river Brahmaputra in Assam. In the present study, 240 specimens were collected from Guwahati and Tezpur in the Brahmaputra River and Silchar in the Barak River to investigate the morphometric and meristic variation among the populations. For this a total of 20 morphometric traits and 11 meristic traits were studied. The mean lengths for most of the morphometric traits were higher for the Barak River except eye diameter, inter orbital length and anal fin length which were significantly higher on the Brahmaputra River, while the post orbital length and pelvic fin length were found to be almost equal. The regressions of standard length with all the morphometric traits except pelvic fin length, pelvic fin base, pectoral fin length, dorsal fin length, anal fin length, pre orbital length, post orbital length, inter orbital length and eye diameter showed significant variation between the rivers. Two meristic traits viz. branched rays in anal fin and gill rakers on the first gill arch also showed significant variation in the samples of the rivers