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.
Description:
A Thesis
Submitted to the Faculty of Agriculture,
Sher-e-Bangla Agricultural University, Dhaka,
in partial fulfillment of the requirements
for the degree of
MASTER OF SCIENCE
IN
BIOTECHNOLOGY
SEMESTER: JULY-DECEMBER, 2021
