DNA barcoding and biometric investigation on the invasive Oreochromis niloticus (Linnaeus, 1758) from the River Yamuna of Uttar Pradesh

Oreochromis niloticus (Linnaeus, 1758), an invasive fish species is rapidly spreading in the Gangetic river system. The aim of the study was to identify and confirm its identity at species level by establishing a barcoding reference datasets in the river Yamuna and then to investigate its morphometric, meristic traits and length-weight relationship of O. niloticus from the Allahabad water of the river Yamuna by the examination of 341 fish specimens collected during October 2011 to September 2012. The taxonomic status of O. niloticus (Linnaeus, 1758), in the river Yamuna was assessed using DNA barcode marker COI gene sequences, have clearly identified the O. niloticus species with 100% similarity value with public database. The length-weight relationships were established as W = 0.029486L^2.881638 and W = 0.058499L^2.661735 for male and female. Differential growth in length-weight between male and female of O. niloticus were significant (p < 0.05), with a greater slope (b) value for male (2.88) than female (2.66). The t statistics estimated for the regression coefficients (b) were significant at 5% level of significance (p < 0.05), indicating an allometric growth pattern. The correlation was highest for the standard length and the total length (0.9878) and minimum for caudal peduncle length and total length (0.8022). Fin formula based on the meristic studies can be written as B₃, D 15–19/_11–15, P₁₄, V 1_/5, A 3/_8–11 and C_16–22.