The Ecological and Economic Importance of Undervalued Fish Species: A Case Study of Bangladesh

Abstract

Bangladesh's freshwater ecosystems contain over 150 small indigenous fish species, many of which remain undervalued in national fishery policies because of their critical ecological and nutritional contributions. While current management frameworks prioritize commercially valuable species such as hilsa and cultivated carps, undervalued fish species face declining populations due to habitat loss, overfishing, pollution, and climate change. This study examined the knowledge gap by examining the ecological importance, nutritional value, and conservation requirements of undervalued fish in Bangladesh. A mixed-methods approach was used, linking a systematic literature review of 33 peer-reviewed articles (2000–2025) following the PRISMA guidelines with expert interviews to authenticate the findings. The results showed that undervalued species function as essential mid-trophic bridges, shifting energy from primary producers to higher trophic levels while performing vital ecosystem functions, including nutrient cycling, sediment bioturbation, and water quality regulation. Nutritionally, Amblypharyngodon mola contains up to 50 times more vitamin A and three times more calcium than cultivated carps, offering cost-effective solutions to micronutrient deficiencies among vulnerable populations. This study proposes integrating undervalued species into national fishery policies, restoring floodplain connectivity, expanding fish sanctuaries, and adopting ecosystem-based management methods. These findings highlight the urgent need to reposition endangered fish species as ecological keystones for biodiversity conservation and food security in Bangladesh.