Biodiversity assemblages and conservation necessities of ecologically sensitive natural wetlands of north-eastern Bangladesh

North-Eastern region of Bangladesh is very promising for freshwater capture fisheries, nevertheless, comprehensive assessment on faunal composition and diversity assemblages of natural wetlands are scant.This study identifies the occurrence, different biodiversity indices and composition of fish with various gear types by means of qualitative and quantitative approaches in Tanguarhaor and Dekarhaor. A total of 75 fish species were identified, of which 53 % were Cypriniformes, followed by Siluriformes (15 %), Perciformes (14 %), Channiformes (7 %) and Clupeiformes (4 %). Among the identified taxa 42 species were not threatened, 12 vulnerable, 11 endangered and 8 critically endangered. The values of diversity indices explicitly Shannon-Weiner (H'), Pielou evenness (J'), Margalef richness (d) and Simpson dominance (c) indices indicated that Tanguarhaorwasmore diversified and evenly distributed than Dekharhaor. For effective management of the haorscomprehensive stock assessment, establishment of fish sanctuaries, and combination of input and output control is suggested.