Spatiotemporal variations in finfish assemblage and diversity indices in relation to ecological indicators of the Atrai River, Dinajpur, Bangladesh

Abstract

Fish assemblage and their association with major ecological factors were spatiotemporally conducted from January to December 2016 in the Atrai River, Dinajpur, Bangladesh. A total of 14,137 specimens belonging to 61 species, 45 genera, 18 families and 6 orders was recorded. The proportion of threatened and omnivore fish was 22.85% and 66.66%, respectively. The dominated (> 4.60%) species were Pethia ticto followed by Aspidoparia jaya, Puntius sophore, Salmophasia bacaila and Barilius barna. Temperature, depth and rainfall were the main environmental gradients to alter species biomass, biodiversity and taxonomic indices and fish assembly. The low level of river flow and water availability during autumn and winter seasons forced the fish to aggregate at higher water depth for their existence expressing unequal aquatic state and taxa. However, the study on spatiotemporal diversity of fish assemblage in this river will be an effective tool to conserve both the native and threatened species. Keywords: Biodiversity and taxonomic indices, Ecological factors, Finfishes, Atrai River