Threats to Fish Biodiversity in Bangladesh Waters and Measures for Revival of Declining Population

Abstract

Bangladesh is rich in fish biodiversity covering interconnected riverine, coastal and marine habitats. Many researchers reported different potentials and threats of biodiversity and suggested measures to minimize the threats. Revival story of hilsa and relevant fish population revealed hopes and ways of sustainable biodiversity management. We attempted to compile the fragmentary fish biodiversity information, described the revival story of hilsa and other important fish along with the threats and challenges of the fish biodiversity and suggested measures for the sustainable management of the fish biodiversity. Freshwater habitats are rich in biodiversity with 265 fresh water fish species. The Meghna River supports the highest 200 fish species as a single river. The marine habitat covers an area of 118,813 km2 that produces 0.66 million tons of fish annually and owned 475 species in 1971, but recent exploration suggests the existence of 394 species. However, the species diversities are increasingly facing threats from direct and indirect anthropogenic activities including juvenile catch, overexploitation, creating obstructions in the migratory routes, pollutions and climate change. Hilsa, the most important species also severely faced these threats and as a result, the production declined to below 0.20 million tons in 2002-2003. Joint efforts of all stakeholders through incentive based co-management led to the hilsa fishery revival, and its production reached 0.533 million tons in 2019. Along with the hilsa, other interdependent species, especially four important catfish species ( Pangasius pangasius, Sperata aor, Bagarius bagarius and Rita rita ) have also revived remarkably. Following the lessons learned from the revival of fishery, several management measures focusing on juvenile conservation, protection of broodstock, harmful gear elimination, optimum exploitation, pollution control, incentive-based co-management, habitat protection, restoration and rehabilitation are suggested to ensure maximum sustainable productions and biodiversity conservation focusing on vulnerable and threatened species and improved livelihoods resilience of fishers through good governance.