Diversity and Community Structure of Marine Fishes in the Lower Meghna River Estuary, Bangladesh: A Case Study in Hatiya and Nijhum Dwip

Hatiya and Nijhum Dwip are the most two important islands in the Meghna River Estuary in Bangladesh, especially in terms of marine fisheries resources. The purpose of the study was to investigate the diversity and community structure of marine fishes in these areas during pre-monsoon. A total of 27 fish species were found under 9 orders, among which 40.7% were frequent, 25.92% were moderately frequent, and 33.33% of species were less frequent. Perciformes and Siluriformes orders were found to be dominant ones. The flathead sillago Sillaginopsis panijus, Paradise threadfin Polynemus paradiseus and Engraved catfish Nemopteyrx nenga were the most dominant and frequently available in all stations. Moreover, the Bombay duck Harpadon nehereus was dominant at the Tamaraddi Ghat (20.68%), Kazir Bazar (11.84%) and Oskhali Bazar (11.59%), whereas the Panna croaker Panna microdon was dominant at Namar Bazar (11.86%), Nijhum Dwip. HilsaTenualosa ilisha and Asian sea bass Lates calcarifer showed lower abundance (<5%). Higher values of marine fish species diversity, evenness and richness were found at Hatiya. Although 80% of marine fish species were least concern and near threatened, a sustainable marine fisheries management plan would be highly recommended to conserve these fishery resources.