Ichthyofauna assemblage and their spatiotemporal distribution: a case study in Asura beel of Dinajpur, Bangladesh

Abstract

Ichthyofauna diversity acts as a bio-indicator and is playing a significant role in the sustainability of an aquatic environment. The present study explores the ichthyofauna assemblage in one of the largest wetlands of Bangladesh known as Asura beel located in Dinajpur district. Fortnightly fish samplings were done from November 2017 to October 2018 considering three seasons as winter,summer, and rainy. Fish biodiversity was assessed with their threatened status and analyzed seasonal abundance with the diversity indices. Findings revealed a total of 35 identified species of fish belonging to 7 orders, 17 families, and 26 genera. According to IUCN- Bangladesh 2015, the current research recorded 6 fish species as vulnerable (17%). While only 1 species is data deficient (3%), 6 species are endangered (17%), and the other 22 species are not threatened (63%). Among the fish species, Amblypharyngodon mola of Cypriniformes order contributed the highest abundance (12%). On the contrary, Ostreobrama cotio and Macrognathus armatus both represented the lowest abundance by contributing 0.35%. The survey also reported that the seasonal diversity indices and richness values did not vary significantly according to seasons although the number of catches was found higher in the winter season followedby summer and rainy seasons.