| dc.description.abstract | The present study was conducted to assess the fish biodiversity and threatened status of fishes
in the Dhepa River from September 2015 to April 2016. The fishes were collected from 3
sampling sites: Kantonagor area, Karnai area and Bangibacha bridge area of the Dhepa river
in each month. Then the collected fish samples were identified by morphometrically and
meristically and preserved with 10% formalin in laboratory. The Shannon-Weiner diversity
index, Margalef’s index, Sampson’s dominance index and evenness were determined by
using PAST software (version 3.11) to describe the abundance and distribution pattern of
fishes. A total of 61 fish species belonging to 8 orders, 18 families and 11 major groups
including prawns were identified. Cypriniformes was recorded as the most diversified fish
group in terms of both number of species and number of individuals observed. The ShannonWeiner diversity index was found highest (3.56) at the Bangibacha bridge area and the lowest
(2.84) at the Karnai area. Higher Shannon-Weiner diversity index value was found in
September and November (3.41) where low during March (2.30). Margalef’s index was
found highest (7.62) at the Bangibacha Bridge area during September (8.38) and the lowest
(5.79) at the Karnai area during April (6.54). On the other hand, evenness index was lowest
(0.37) at the Karnai area during March (0.19) and the highest (0.62) at the Bangibacha Bridge
were in two successive months i.e., in January, February (0.61). The fish species of the
Dhepa river found to be evenly distributed. Simpson's dominance index were found to be
highest (0.11) at the Karnai area during March (0.23) and the lowest (0.04) at the Bangibacha
Bridge area in five successive months i.e., in September, October, November, January and
February (0.05) Species richness and evenness were increased in winter months and
decreased in summer months on the basis of biodiversity index. Among 61 species 6 were
vulnerable, 11 endangered, 2 critically endangered, 23 were least concern, 8 were near
threatened 11 not threatened according to IUCN Bangladesh (2016). Among 25 threatened
fish species, 10 species were abundantly available and 15 species were rarely available in the
Dhepa River. Finally, it is recommended that establishment of fish sanctuaries could be the
effective means to conserve both threatened and non-threatened fish species of the river. | en_US |
