Production Trends, and Challenges for Biodiversity Conservation and Sustainable Fisheries Management of Kaptai Lake, the Largest Reservoir in Bangladesh

Abstract

Kaptai Lake (KL), the largest artificial lake in Bangladesh, supports an important inland open water fishery. Nevertheless, detailed studies on its fish diversity and environmental threats are still limited. Hence, a study was conducted to evaluate the current fish management scenarios, fish production, relative abundance to improve the production and biodiversity of KL. Data were collected from stakeholders through personal observation, focus group discussions, and cross-check interviews from September 2018 to July 2019. The fish production of KL increased from 1,200 metric tons (MT) in 1965–1966 to 10,577 MT in 2018–2019. The output of the lake was dominated by small fish remarkably, Gudusia chapra (Hamilton, 1822), Gonialosa manmina (Hamilton, 1822), and Corica soborna Hamilton, 1822, accounting for 64 % of the total production in 2018–2019. A total of seventy-six fish species were observed under ten orders, including seven exotic fish species. According to the IUCN Bangladesh, 14 % of total species were identified as vulnerable, 11 % as endangered, 3 % as critically endangered, 11 % as near threatened and 51 % as least concern. The study also identified that climate change and various human-driven causes threaten the fish production and biodiversity of this lake. These findings suggest that community-based fisheries management, protection of natural breeding grounds of carps, control of pollution, amendment of existing fishing laws, and collaborative research would be a necessary approach for mitigating the negative environmental impact of this lake. The overall practical knowledge of this investigation could assist in policymaking and further research.