DNA BARCODING OF SILURIFORM FISHES OF THE MEGHNA RIVER ESTRUARY

Abstract

The Meghna river estuary is the largest estuarine ecosystem in Bangladesh and the fish assemblage in this estuary is highly diverse. Estuaries are also very important as breeding and nursery grounds for a wide variety of fishes. Fish samples were collected from the different zone of the Meghna estuary around the year July 2020 to May 2021. In the present study, a total of 9 species were identified from the 7 seven genera and two families (Bagridae and Schilbeidae) under the order Siluriformes based on DNA barcoding approach along with morphology. The species were M. bleekeri, M. gulio, M. vittatus, R. rita, S. aor from the Bagridae family and A. coila, C. garua, E. vacha, S. silondia from the Schilbeidae family. The barcode sequences obtained from the present study showed high identity (> 99%) with the reference sequences deposited in the GenBank database. The assessment of species identities with previously known sequences and closely related species in NCBI BLAST generated 99% of identities indicating the effectiveness of COI sequences to provide species-level resolution. Sequences of the present study were clustered in a single clade with the sequences of conspecific species from GenBank which validate the genetic identification of the studied species. Genetic distances among the sequences of the present study and its compared sequences from GenBank ranged from 0.00 (0.2%) to 0.003 (0.3%) which also validates the genetic identification of this species. Fish diversity in the Meghna has long been declining due to the number of anthropogenic and natural factors. This study provides information on the species diversity of Siluriformes that will help in the management and conservation of the fish fauna of the Meghna river system.